National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/6829

TDMS Study 97006-01 Pathology Tables

NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52

                                                          FINAL#1/RATS




       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: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 6| 7| 7| 5| 7| 7| 7| 7| 7| 5| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 7|             
                             DAY ON TEST   | 5| 1| 2| 2| 2| 2| 2| 1| 2| 2| 8| 2| 9| 2| 0| 2| 2| 2| 2| 2| 2| 2| 5| 2| 2|             
                                           | 0| 6| 9| 8| 3| 8| 8| 6| 8| 8| 3| 9| 6| 8| 7| 9| 7| 7| 9| 9| 7| 8| 4| 9| 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|             
   FISCHER 344 RATS 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                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |             4                                                            |             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |             X                                                            |             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Necrosis                             |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     | X        X     X     X  X  X     X  X  X     X  X  X  X  X  X  X        X|             
      Clear Cell Focus                     |          X              X        X           X     X                     |             
      Eosinophilic Focus                   |                   X                       X                    X         |             
      Hepatodiaphragmatic Nodule           | 4     4     4           4                             4           4      |             
      Mixed Cell Focus                     |                                                                          |             
      Vacuolization Cytoplasmic            |                      3                                                   |             
      Hepatocyte, Regeneration             |                                           4                              |             
                                           |__________________________________________________________________________|             
   Mesentery                               |    +     +           +     +     +        +                    +         |             
      Fibrosis                             |                                                                          |             
      Necrosis                             |    3     3           3     3     3        3                    3         |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Acinus, Atrophy                      |                                                                   3      |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperkeratosis                       |             2                                                            |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page   2                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 6| 7| 7| 5| 7| 7| 7| 7| 7| 5| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 7|             
                             DAY ON TEST   | 5| 1| 2| 2| 2| 2| 2| 1| 2| 2| 8| 2| 9| 2| 0| 2| 2| 2| 2| 2| 2| 2| 5| 2| 2|             
                                           | 0| 6| 9| 8| 3| 8| 8| 6| 8| 8| 3| 9| 6| 8| 7| 9| 7| 7| 9| 9| 7| 8| 4| 9| 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|             
   FISCHER 344 RATS 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                  |                                                                          |             
      Ulcer                                |                                                                      4   |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Tongue                                  |                                                                          |             
      Epithelium, Hyperplasia              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Vacuolization Cytoplasmic            |          2              2                                               3|             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  M  +  +  M  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                       1           4      |             
      Hyperplasia                          | 4        4        4              3                    2           3      |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      C-Cell, Hyperplasia                  |                   4                                                      |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |__________________________________________________________________________|             
   Peritoneum                              | +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page   3                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 6| 7| 7| 5| 7| 7| 7| 7| 7| 5| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 7|             
                             DAY ON TEST   | 5| 1| 2| 2| 2| 2| 2| 1| 2| 2| 8| 2| 9| 2| 0| 2| 2| 2| 2| 2| 2| 2| 5| 2| 2|             
                                           | 0| 6| 9| 8| 3| 8| 8| 6| 8| 8| 3| 9| 6| 8| 7| 9| 7| 7| 9| 9| 7| 8| 4| 9| 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 | 2                       3                                                |             
      Hyperplasia                          |                         3                                                |             
      Inflammation, Chronic                |                                                                          |             
                                           |__________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                4        4                          3                     |             
      Cyst, Multiple                       |                                                                          |             
                                           |__________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                                          |             
      Decidual Reaction                    |                                  3                                       |             
      Hemorrhage                           |                                                                          |             
      Necrosis                             |                         4                                      4         |             
      Endometrium, Hyperplasia             |                                                                          |             
      Endometrium, Inflammation,           |                                                                          |             
          Suppurative                      |                                                                   3      |             
                                           |__________________________________________________________________________|             
   Vagina                                  |                                                                +  +      |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node                              |                                                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | M  M  M  M  M  +  M  +  M  M  +  M  M  M  +  M  M  M  M  M  M  M  M  M  M|             
      Ectasia                              |                      2                                                   |             
      Pigmentation                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | 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|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page   4                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 6| 7| 7| 5| 7| 7| 7| 7| 7| 5| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 7|             
                             DAY ON TEST   | 5| 1| 2| 2| 2| 2| 2| 1| 2| 2| 8| 2| 9| 2| 0| 2| 2| 2| 2| 2| 2| 2| 5| 2| 2|             
                                           | 0| 6| 9| 8| 3| 8| 8| 6| 8| 8| 3| 9| 6| 8| 7| 9| 7| 7| 9| 9| 7| 8| 4| 9| 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|             
   FISCHER 344 RATS 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               |                                                                          |             
      Hemorrhage                           |                               4                                          |             
      Necrosis                             |                                           4                              |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Galactocele                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst Epithelial Inclusion            |                                                                          |             
      Hyperkeratosis                       |       3                                                                  |             
      Ulcer                                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         |                +     +     +                                   +         |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Compression                          |                      3              3     4  2                       4   |             
      Hemorrhage                           |                                           1                          4   |             
      Thrombosis                           |                                                                          |             
      Cerebrum, Pigmentation               |                                                                          |             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        |                +     +     +                                   +         |             
                                           |__________________________________________________________________________|             
   Spinal Cord                             |                +     +     +                                   +         |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |                4                                                         |             
      Inflammation, Chronic                |                                        1                                 |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page   5                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 6| 7| 7| 5| 7| 7| 7| 7| 7| 5| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 7|             
                             DAY ON TEST   | 5| 1| 2| 2| 2| 2| 2| 1| 2| 2| 8| 2| 9| 2| 0| 2| 2| 2| 2| 2| 2| 2| 5| 2| 2|             
                                           | 0| 6| 9| 8| 3| 8| 8| 6| 8| 8| 3| 9| 6| 8| 7| 9| 7| 7| 9| 9| 7| 8| 4| 9| 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|             
   FISCHER 344 RATS 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                 |                                                                          |             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                                                          |             
      Alveolar Epithelium, Hyperplasia     |             1                                1                       2   |             
      Alveolus, Emphysema                  |                                                                          |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Histiocyte                      | 1        1           2  1                    1        1     2           2|             
      Bronchiole, Hyperplasia              |                   3                                                      |             
      Interstitium, Fibrosis               |                      1                                                   |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Nasolacrimal Duct, Inflammation,     |                                                                          |             
           Suppurative                     |                                                                         2|             
      Olfactory Epithelium, Degeneration,  |                                                                          |             
           Hyaline                         |                                                                          |             
      Respiratory Epithelium, Degeneration,|                                                                          |             
           Hyaline                         |    1                                   2        1  2                     |             
                                           |__________________________________________________________________________|             
   Pleura                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrosis                             |    1                 1  1                             1     1           2|             
      Inflammation, Chronic                |    1                 2  1                             1     2           2|             
      Mesothelium, Hyperplasia             |                                                                          |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Ear                                     |                                                    +                     |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lens, Cataract                       |                                                                          |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Nephropathy                          |       1        1     1     1        1  2  4  1  1     1     1            |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page   6                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 6| 7| 7| 5| 7| 7| 7| 7| 7| 5| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 7|             
                             DAY ON TEST   | 5| 1| 2| 2| 2| 2| 2| 1| 2| 2| 8| 2| 9| 2| 0| 2| 2| 2| 2| 2| 2| 2| 5| 2| 2|             
                                           | 0| 6| 9| 8| 3| 8| 8| 6| 8| 8| 3| 9| 6| 8| 7| 9| 7| 7| 9| 9| 7| 8| 4| 9| 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
      Papilla, Mineralization              |                      1                 1                                 |             
      Pelvis, Transitional Epithelium,     |                                                                          |             
           Hyperplasia                     |                                                                          |             
      Pelvis, Transitional Epithelium,     |                                                                          |             
           Mineralization                  |                                     1                                    |             
      Renal Tubule, Hyperplasia            |                                           2                              |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                                                          |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   7                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 5| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 3| 7| 7| 7| 7|            |
                             DAY ON TEST   | 8| 7| 2| 2| 2| 2| 2| 2| 2| 0| 2| 2| 2| 0| 2| 2| 2| 2| 2| 4| 7| 1| 2| 2| 2|            |
                                           | 5| 6| 7| 9| 9| 8| 7| 8| 8| 6| 8| 8| 7| 9| 8| 9| 9| 8| 8| 3| 0| 4| 7| 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     |
   FISCHER 344 RATS 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        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Foreign Body                         |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Foreign Body                         |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Necrosis                             |    4                                                                     |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Basophilic Focus                     | X     X  X  X  X  X  X  X  X     X     X     X  X  X        X  X  X  X  X|     36     |
      Clear Cell Focus                     |       X  X              X        X                                   X  X|     11     |
      Eosinophilic Focus                   |                                                                          |      3     |
      Hepatodiaphragmatic Nodule           |                                  4                          4            |      8  4.0|
      Mixed Cell Focus                     |                                  X                                       |      1     |
      Vacuolization Cytoplasmic            | 2                                                              3         |      3  2.7|
      Hepatocyte, Regeneration             |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |       +     +     +  +              +  +        +  +           +     +  +|  18        |
      Fibrosis                             |                                                                      3   |      1  3.0|
      Necrosis                             |       3     3     3  3              3  3        3  3           3     3  3|     18  3.0|
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Acinus, Atrophy                      |                                                                          |      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   8                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 5| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 3| 7| 7| 7| 7|            |
                             DAY ON TEST   | 8| 7| 2| 2| 2| 2| 2| 2| 2| 0| 2| 2| 2| 0| 2| 2| 2| 2| 2| 4| 7| 1| 2| 2| 2|            |
                                           | 5| 6| 7| 9| 9| 8| 7| 8| 8| 6| 8| 8| 7| 9| 8| 9| 9| 8| 8| 3| 0| 4| 7| 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     |
   FISCHER 344 RATS 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                  |                                                                          |            |
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperkeratosis                       |                                                                          |      1  2.0|
      Ulcer                                |                                                                4         |      2  4.0|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Tongue                                  |                +                                                         |   1        |
      Epithelium, Hyperplasia              |                4                                                         |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       |                                  2                                       |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Vacuolization Cytoplasmic            |       3                                1  3  2  1        4               |      9  2.3|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          | 3                                                                        |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +|  46        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +|  49        |
      Cyst                                 |                                                       3                  |      3  2.7|
      Hyperplasia                          |       2        3              3           3                 4            |     11  3.2|
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 5| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 3| 7| 7| 7| 7|            |
                             DAY ON TEST   | 8| 7| 2| 2| 2| 2| 2| 2| 2| 0| 2| 2| 2| 0| 2| 2| 2| 2| 2| 4| 7| 1| 2| 2| 2|            |
                                           | 5| 6| 7| 9| 9| 8| 7| 8| 8| 6| 8| 8| 7| 9| 8| 9| 9| 8| 8| 3| 0| 4| 7| 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     |
   FISCHER 344 RATS 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                   |                                                                          |            |
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      C-Cell, Hyperplasia                  |          3              2                          2                     |      4  2.8|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Peritoneum                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |                                                                          |      2  2.5|
      Hyperplasia                          |                                                                          |      1  3.0|
      Inflammation, Chronic                |                                                                3         |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |       3                 3  3                                             |      6  3.3|
      Cyst, Multiple                       |                                     3                                    |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |                                     4                                    |      1  4.0|
      Decidual Reaction                    |                                                                          |      1  3.0|
      Hemorrhage                           |                                                             4            |      1  4.0|
      Necrosis                             |                                                                          |      2  4.0|
      Endometrium, Hyperplasia             |                                     1                                    |      1  1.0|
      Endometrium, Inflammation,           |                                                                          |            |
          Suppurative                      |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Vagina                                  |                                                                          |   2        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |                                                          +               |   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: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 5| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 3| 7| 7| 7| 7|            |
                             DAY ON TEST   | 8| 7| 2| 2| 2| 2| 2| 2| 2| 0| 2| 2| 2| 0| 2| 2| 2| 2| 2| 4| 7| 1| 2| 2| 2|            |
                                           | 5| 6| 7| 9| 9| 8| 7| 8| 8| 6| 8| 8| 7| 9| 8| 9| 9| 8| 8| 3| 0| 4| 7| 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     |
   FISCHER 344 RATS 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               |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | M  M  M  M  M  M  M  M  M  M  +  M  M  M  M  M  +  +  M  +  M  +  M  M  M|   9        |
      Ectasia                              |                                                    3                     |      2  2.5|
      Pigmentation                         |                                                    3                     |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  +  M  M|   1        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  M  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  46        |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemorrhage                           |                                                                          |      1  4.0|
      Necrosis                             |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Galactocele                          |                                           4                              |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst Epithelial Inclusion            |                                                                4         |      1  4.0|
      Hyperkeratosis                       |                                                                          |      1  3.0|
      Ulcer                                |                                        3                                 |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         |             +  +     +                          +     +  +               |  10        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS 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  11                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 5| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 3| 7| 7| 7| 7|            |
                             DAY ON TEST   | 8| 7| 2| 2| 2| 2| 2| 2| 2| 0| 2| 2| 2| 0| 2| 2| 2| 2| 2| 4| 7| 1| 2| 2| 2|            |
                                           | 5| 6| 7| 9| 9| 8| 7| 8| 8| 6| 8| 8| 7| 9| 8| 9| 9| 8| 8| 3| 0| 4| 7| 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     |
   FISCHER 344 RATS 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 - cont                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Compression                          | 3                          4                                   4         |      8  3.4|
      Hemorrhage                           | 4                          4                                   3         |      5  3.2|
      Thrombosis                           |                                                          4               |      1  4.0|
      Cerebrum, Pigmentation               |                                                 2                        |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        |             +  +     +                          +     +  +               |  10        |
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             |             +  +     +                          +     +  +               |  10        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Foreign Body                         |                                                                          |      1  4.0|
      Inflammation, Chronic                |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic                |                            1           1                                 |      2  1.0|
      Alveolar Epithelium, Hyperplasia     |                                                                          |      3  1.3|
      Alveolus, Emphysema                  |                            3                                             |      1  3.0|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Histiocyte                      |             1                          1        1                 1  1   |     13  1.2|
      Bronchiole, Hyperplasia              |                                                                          |      1  3.0|
      Interstitium, Fibrosis               |                                                          1               |      2  1.0|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Nasolacrimal Duct, Inflammation,     |                                                                          |            |
           Suppurative                     |                   1              3        2           1                  |      5  1.8|
      Olfactory Epithelium, Degeneration,  |                                                                          |            |
           Hyaline                         |                                                          2               |      1  2.0|
      Respiratory Epithelium, Degeneration,|                                                                          |            |
           Hyaline                         |          1           1  1                                            2  2|      9  1.4|
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 5| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 3| 7| 7| 7| 7|            |
                             DAY ON TEST   | 8| 7| 2| 2| 2| 2| 2| 2| 2| 0| 2| 2| 2| 0| 2| 2| 2| 2| 2| 4| 7| 1| 2| 2| 2|            |
                                           | 5| 6| 7| 9| 9| 8| 7| 8| 8| 6| 8| 8| 7| 9| 8| 9| 9| 8| 8| 3| 0| 4| 7| 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     |
   FISCHER 344 RATS 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|            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
   Pleura                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrosis                             |             1              1           1        1                 2  1   |     12  1.2|
      Inflammation, Chronic                |                            2                                             |      7  1.6|
      Mesothelium, Hyperplasia             |                                        1                                 |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Ear                                     |                                                                          |   1        |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lens, Cataract                       |                            3                                            4|      2  3.5|
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Nephropathy                          | 1     1                          3  1           1     1        2        1|     19  1.4|
      Papilla, Mineralization              |                                                 1                        |      3  1.0|
      Pelvis, Transitional Epithelium,     |                                                                          |            |
           Hyperplasia                     |                                                    1                     |      1  1.0|
      Pelvis, Transitional Epithelium,     |                                                                          |            |
           Mineralization                  |                         1  1  1     2  1     1  1  1                     |      9  1.1|
      Renal Tubule, Hyperplasia            |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemorrhage                           |                                                          4               |      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  13                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 5| 7| 7| 6| 5| 3| 7| 7| 7| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 2| 2| 6| 2| 2| 3| 2| 0| 6| 9| 5| 2| 2| 2| 2| 2| 2| 9| 2|             
                                           | 9| 8| 9| 9| 8| 9| 9| 9| 2| 9| 8| 9| 8| 7| 5| 5| 6| 2| 8| 9| 8| 8| 8| 4| 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|             
   FISCHER 344 RATS 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                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Basophilic Focus                     | X  X        X  X  X  X     X  X                       X  X  X  X  X      |             
      Clear Cell Focus                     |       X                                                        X        X|             
      Hepatodiaphragmatic Nodule           |    4  4           4     4                          4              4      |             
      Inflammation, Granulomatous          |                                                                          |             
      Mixed Cell Focus                     |                                                                   X      |             
      Vacuolization Cytoplasmic            |                                           3                          2   |             
      Hepatocyte, Regeneration             |                                                                          |             
      Serosa, Fibrosis                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Mesentery                               |       +  +     +                                +                 +  +  +|             
      Hemorrhage                           |                                                                   3      |             
      Necrosis                             |       3  3     3                                                     3  3|             
                                           |__________________________________________________________________________|             
   Oral Mucosa                             |                                           +                              |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Acinus, Atrophy                      |                                                          2               |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  14                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 5| 7| 7| 6| 5| 3| 7| 7| 7| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 2| 2| 6| 2| 2| 3| 2| 0| 6| 9| 5| 2| 2| 2| 2| 2| 2| 9| 2|             
                                           | 9| 8| 9| 9| 8| 9| 9| 9| 2| 9| 8| 9| 8| 7| 5| 5| 6| 2| 8| 9| 8| 8| 8| 4| 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|             
   FISCHER 344 RATS 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                  |                                                                          |             
      Hyperplasia, Squamous                |                                                                          |             
      Necrosis                             |                                                                      3   |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Tongue                                  |    +                                                                     |             
      Epithelium, Hyperplasia              |    1                                                                     |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       |                                                                          |             
      Atrium, Thrombosis                   |                                                    4                     |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
      Vacuolization Cytoplasmic            |                                  2        3              2               |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
      Hyperplasia                          |             4                                                     4      |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                     4                                    |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  M  +  +  M|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |       1                                   3        4           4         |             
      Hemorrhage                           |                                                    3                     |             
      Hyperplasia                          |    2           3     4        4                 3        4               |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      C-Cell, Hyperplasia                  |                                                       3                  |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  15                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 5| 7| 7| 6| 5| 3| 7| 7| 7| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 2| 2| 6| 2| 2| 3| 2| 0| 6| 9| 5| 2| 2| 2| 2| 2| 2| 9| 2|             
                                           | 9| 8| 9| 9| 8| 9| 9| 9| 2| 9| 8| 9| 8| 7| 5| 5| 6| 2| 8| 9| 8| 8| 8| 4| 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |__________________________________________________________________________|             
   Peritoneum                              |    +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                               4                                          |             
      Hyperplasia                          |                                                                      4   |             
      Inflammation, Chronic                |                                                                          |             
                                           |__________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                         4  2                                2     4      |             
                                           |__________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Endometrium, Hyperplasia             |                2                                                         |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node                              |                                                                          |             
      Pancreatic, Hemorrhage               |                                                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | M  +  M  M  +  M  M  M  M  M  M  M  +  M  M  M  +  +  M  M  +  M  M  +  +|             
      Hemorrhage                           |                                                 2                        |             
      Hyperplasia, Lymphoid                |                                                                      3  3|             
      Pigmentation                         |                                                                      3  2|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | 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|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  +  +  +  +  +  +  M  M  +  +  M  +  +  +  +  +  +  +  M  +  +  +  +|             
      Angiectasis                          |                                           4                              |             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrosis                             |                                                                          |             
      Inflammation, Granulomatous          |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  16                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 5| 7| 7| 6| 5| 3| 7| 7| 7| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 2| 2| 6| 2| 2| 3| 2| 0| 6| 9| 5| 2| 2| 2| 2| 2| 2| 9| 2|             
                                           | 9| 8| 9| 9| 8| 9| 9| 9| 2| 9| 8| 9| 8| 7| 5| 5| 6| 2| 8| 9| 8| 8| 8| 4| 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|             
   FISCHER 344 RATS 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                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Galactocele                          |                                                                          |             
      Epithelium, Hyperplasia              |                                                                          |             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst Epithelial Inclusion            |                               4                                          |             
      Hyperplasia, Focal, Squamous         | 2                                                                        |             
      Inflammation, Acute                  |                                                                          |             
      Ulcer                                |                                                                      4   |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         |             +        +                          +     +                  |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Compression                          |             4                    4     4     3                       4   |             
      Hemorrhage                           |                         3                                                |             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        |             +        +                                +                  |             
                                           |__________________________________________________________________________|             
   Spinal Cord                             |             +        +                                +                  |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |                                                                      4   |             
      Inflammation, Chronic                |                                                                          |             
      Epiglottis, Metaplasia, Squamous     |                                                                          |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  17                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 5| 7| 7| 6| 5| 3| 7| 7| 7| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 2| 2| 6| 2| 2| 3| 2| 0| 6| 9| 5| 2| 2| 2| 2| 2| 2| 9| 2|             
                                           | 9| 8| 9| 9| 8| 9| 9| 9| 2| 9| 8| 9| 8| 7| 5| 5| 6| 2| 8| 9| 8| 8| 8| 4| 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|             
   FISCHER 344 RATS 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                 |                                                                          |             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |       2     2     2                 2                    3               |             
      Alveolar Epithelium, Hyperplasia     |                   1                                                      |             
      Alveolar Epithelium, Metaplasia,     |                                                                          |             
           Squamous                        |                   1                                                      |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Histiocyte                      |       1                                                                  |             
      Bronchiole, Hyperplasia              |                                                                          |             
      Interstitium, Fibrosis               |                                                                          |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |                                                                      3   |             
      Inflammation, Suppurative            |                                                                          |             
      Nasolacrimal Duct, Inflammation,     |                                                                          |             
           Suppurative                     |                                                                   2      |             
      Respiratory Epithelium, Degeneration,|                                                                          |             
           Hyaline                         |                                        2                                 |             
      Respiratory Epithelium, Hyperplasia  |                                                                      2   |             
                                           |__________________________________________________________________________|             
   Pleura                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrosis                             |       2           2        1        2              1     2               |             
      Inflammation, Chronic                |                   2     1  1        1                    3               |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Ear                                     | +                                                                        |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            |                                           4                              |             
      Lens, Cataract                       |                                     4                                    |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  18                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 5| 7| 7| 6| 5| 3| 7| 7| 7| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 2| 2| 6| 2| 2| 3| 2| 0| 6| 9| 5| 2| 2| 2| 2| 2| 2| 9| 2|             
                                           | 9| 8| 9| 9| 8| 9| 9| 9| 2| 9| 8| 9| 8| 7| 5| 5| 6| 2| 8| 9| 8| 8| 8| 4| 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
      Nephropathy                          | 1        1  1        1  1  1  1  2  1  1  2  2     1           1  1  1  2|             
      Papilla, Mineralization              | 1                             1        1                                 |             
      Pelvis, Transitional Epithelium,     |                                                                          |             
           Hyperplasia                     |                                                                          |             
      Pelvis, Transitional Epithelium,     |                                                                          |             
           Mineralization                  |             2                    1                       1              1|             
      Renal Tubule, Cyst                   |                                                                          |             
      Renal Tubule, Hyperplasia            |                                                                          |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  19                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5|            |
                             DAY ON TEST   | 2| 5| 2| 0| 2| 2| 2| 2| 2| 1| 2| 6| 2| 2| 9| 2| 2| 1| 2| 2| 2| 2| 2| 2| 3|            |
                                           | 8| 5| 9| 7| 8| 9| 9| 9| 9| 8| 9| 9| 9| 8| 3| 1| 8| 2| 9| 8| 9| 8| 9| 8| 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     |
   FISCHER 344 RATS 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        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  A|  48        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Angiectasis                          |                                           3                              |      1  3.0|
      Basophilic Focus                     |       X     X  X  X  X        X        X  X     X  X           X         |     24     |
      Clear Cell Focus                     | X     X                                         X  X        X     X  X   |     10     |
      Hepatodiaphragmatic Nodule           | 4     4           4        4        4           4                        |     12  4.0|
      Inflammation, Granulomatous          |                                                                      2   |      1  2.0|
      Mixed Cell Focus                     |                            X                                      X      |      3     |
      Vacuolization Cytoplasmic            |                                           2                              |      3  2.3|
      Hepatocyte, Regeneration             |                4                                                         |      1  4.0|
      Serosa, Fibrosis                     |                   2                                                      |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |       +        +  +  +              +     +     +  +        +  +         |  17        |
      Hemorrhage                           |                                                                          |      1  3.0|
      Necrosis                             |       3        3  3  3              3     3     3  3        3  3         |     15  3.0|
                                           |__________________________________________________________________________|____________|
   Oral Mucosa                             |                                                                          |   1        |
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Acinus, Atrophy                      |                                                                          |      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  20                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5|            |
                             DAY ON TEST   | 2| 5| 2| 0| 2| 2| 2| 2| 2| 1| 2| 6| 2| 2| 9| 2| 2| 1| 2| 2| 2| 2| 2| 2| 3|            |
                                           | 8| 5| 9| 7| 8| 9| 9| 9| 9| 8| 9| 9| 9| 8| 3| 1| 8| 2| 9| 8| 9| 8| 9| 8| 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     |
   FISCHER 344 RATS 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                  |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Squamous                |          2                 2                                             |      2  2.0|
      Necrosis                             |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Tongue                                  |                                                                          |   1        |
      Epithelium, Hyperplasia              |                                                                          |      1  1.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       |             3                                                            |      1  3.0|
      Atrium, Thrombosis                   |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                                    2                     |      1  2.0|
      Vacuolization Cytoplasmic            |                      3                                                   |      4  2.5|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |             4                                                            |      1  4.0|
      Hyperplasia                          |                                                                          |      2  4.0|
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  M  +  +  M  +  +  +  +  +  +  M  M  +  +  +  M  M  M  +  +  +|  40        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5|            |
                             DAY ON TEST   | 2| 5| 2| 0| 2| 2| 2| 2| 2| 1| 2| 6| 2| 2| 9| 2| 2| 1| 2| 2| 2| 2| 2| 2| 3|            |
                                           | 8| 5| 9| 7| 8| 9| 9| 9| 9| 8| 9| 9| 9| 8| 3| 1| 8| 2| 9| 8| 9| 8| 9| 8| 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     |
   FISCHER 344 RATS 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                   |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |       4                       4                                          |      6  3.3|
      Hemorrhage                           |                                  4                                       |      2  3.5|
      Hyperplasia                          | 4                             4        3     3                       4   |     11  3.5|
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      C-Cell, Hyperplasia                  |                                     3                                    |      2  3.0|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Peritoneum                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |          2     2                                                         |      3  2.7|
      Hyperplasia                          | 4                                                              4         |      3  4.0|
      Inflammation, Chronic                |                                                                3         |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |             4  3  2        3                                1  3         |     10  2.8|
                                           |__________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Endometrium, Hyperplasia             |                                        2                                 |      2  2.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |          +                                                           +   |   2        |
      Pancreatic, Hemorrhage               |                                                                      3   |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | M  M  +  M  M  M  M  M  M  M  M  M  M  M  M  +  M  M  +  +  M  M  M  M  M|  12        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5|            |
                             DAY ON TEST   | 2| 5| 2| 0| 2| 2| 2| 2| 2| 1| 2| 6| 2| 2| 9| 2| 2| 1| 2| 2| 2| 2| 2| 2| 3|            |
                                           | 8| 5| 9| 7| 8| 9| 9| 9| 9| 8| 9| 9| 9| 8| 3| 1| 8| 2| 9| 8| 9| 8| 9| 8| 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     |
   FISCHER 344 RATS 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               |                                                                          |            |
      Hemorrhage                           |                                                                          |      1  2.0|
      Hyperplasia, Lymphoid                |                                                                          |      2  3.0|
      Pigmentation                         |                                                                          |      2  2.5|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | 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|            |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|  44        |
      Angiectasis                          |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrosis                             |             2                                                            |      1  2.0|
      Inflammation, Granulomatous          |                                                                      3   |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Galactocele                          |                                                    4                     |      1  4.0|
      Epithelium, Hyperplasia              |    3                                                                     |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst Epithelial Inclusion            |                                                                          |      1  4.0|
      Hyperplasia, Focal, Squamous         |                                                                          |      1  2.0|
      Inflammation, Acute                  |                                                          2        2      |      2  2.0|
      Ulcer                                |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         |                +                                                         |   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  23                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5|            |
                             DAY ON TEST   | 2| 5| 2| 0| 2| 2| 2| 2| 2| 1| 2| 6| 2| 2| 9| 2| 2| 1| 2| 2| 2| 2| 2| 2| 3|            |
                                           | 8| 5| 9| 7| 8| 9| 9| 9| 9| 8| 9| 9| 9| 8| 3| 1| 8| 2| 9| 8| 9| 8| 9| 8| 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     |
   FISCHER 344 RATS 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        |
      Compression                          |    4           4     3     4              3                    4         |     11  3.7|
      Hemorrhage                           |                                  4                 4           2         |      4  3.3|
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        |                +                                                         |   4        |
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             |                +                                                         |   4        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Foreign Body                         |                4                                                         |      2  4.0|
      Inflammation, Chronic                |                3                                                         |      1  3.0|
      Epiglottis, Metaplasia, Squamous     |                         2                                                |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic                | 2              2                          1     1  1                     |     10  1.8|
      Alveolar Epithelium, Hyperplasia     | 2                 3                             2           2            |      5  2.0|
      Alveolar Epithelium, Metaplasia,     |                                                                          |            |
           Squamous                        |                                                                          |      1  1.0|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Histiocyte                      |                                                                   1      |      2  1.0|
      Bronchiole, Hyperplasia              |                                     2     2                              |      2  2.0|
      Interstitium, Fibrosis               | 2                                                           2            |      2  2.0|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Foreign Body                         |                                     3                                    |      2  3.0|
      Inflammation, Suppurative            |                                        2                                 |      1  2.0|
      Nasolacrimal Duct, Inflammation,     |                                                                          |            |
           Suppurative                     |                      2                                                   |      2  2.0|
      Respiratory Epithelium, Degeneration,|                                                                          |            |
           Hyaline                         |                            1                       2                     |      3  1.7|
      Respiratory Epithelium, Hyperplasia  |                                        2                                 |      2  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  24                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5|            |
                             DAY ON TEST   | 2| 5| 2| 0| 2| 2| 2| 2| 2| 1| 2| 6| 2| 2| 9| 2| 2| 1| 2| 2| 2| 2| 2| 2| 3|            |
                                           | 8| 5| 9| 7| 8| 9| 9| 9| 9| 8| 9| 9| 9| 8| 3| 1| 8| 2| 9| 8| 9| 8| 9| 8| 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     |
   FISCHER 344 RATS 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|            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Pleura                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrosis                             |                2                                                         |      7  1.7|
      Inflammation, Chronic                |                3                                   1                     |      7  1.7|
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Ear                                     |                                                                          |   1        |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Suppurative            |                                                                          |      1  4.0|
      Lens, Cataract                       |                                                          2              3|      3  3.0|
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Nephropathy                          | 2  2  2        2     3  2  2  2        1  3     1  1  2  1  2  1  2  1   |     35  1.5|
      Papilla, Mineralization              |                                           1                    1         |      5  1.0|
      Pelvis, Transitional Epithelium,     |                                                                          |            |
           Hyperplasia                     |                                           1                              |      1  1.0|
      Pelvis, Transitional Epithelium,     |                                                                          |            |
           Mineralization                  |    1  1                                                                  |      6  1.2|
      Renal Tubule, Cyst                   |                                                       X                  |      1     |
      Renal Tubule, Hyperplasia            |                      2                                                   |      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  25                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 7| 7| 7| 7| 6| 7| 7| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 8| 2| 2| 2| 2| 2| 4| 2| 2| 7| 7| 5| 5| 2| 2| 2| 2| 2| 2| 1| 2| 2| 0| 0| 1|             
                                           | 1| 8| 7| 8| 8| 8| 2| 8| 6| 4| 7| 3| 3| 1| 8| 8| 9| 6| 9| 6| 9| 8| 2| 9| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     |    X  X  X  X  X     X     X  X  X  X  X        X  X     X  X  X         |             
      Clear Cell Focus                     | X  X                 X                          X           X            |             
      Eosinophilic Focus                   |                                                       X                  |             
      Hepatodiaphragmatic Nodule           | 4                    4           4     4           4  4                  |             
      Necrosis                             |                                                                      2   |             
      Vacuolization Cytoplasmic            |                                        3              2        2         |             
      Hepatocyte, Regeneration             |                                                                   4      |             
                                           |__________________________________________________________________________|             
   Mesentery                               | +           +  +                       +  +  +           +  +  +         |             
      Inflammation, Granulomatous          |             2                                                            |             
      Necrosis                             | 3           3  3                       3  3  3           3  3  3         |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Acinus, Atrophy                      |                                  2                                       |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Squamous                |                                                          2        3      |             
      Ulcer                                |                                                                          |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  26                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 7| 7| 7| 7| 6| 7| 7| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 8| 2| 2| 2| 2| 2| 4| 2| 2| 7| 7| 5| 5| 2| 2| 2| 2| 2| 2| 1| 2| 2| 0| 0| 1|             
                                           | 1| 8| 7| 8| 8| 8| 2| 8| 6| 4| 7| 3| 3| 1| 8| 8| 9| 6| 9| 6| 9| 8| 2| 9| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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                  |                                                                          |             
                                           |__________________________________________________________________________|             
   Tongue                                  |                                        +                    +            |             
      Epithelium, Hyperplasia              |                                        1                    3            |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       | 1                                                                        |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
      Vacuolization Cytoplasmic            | 1                       3              4  2           3                  |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                      3                                                   |             
      Hemorrhage                           |                            4              3                              |             
      Hyperplasia                          |          4  2     4                                            3         |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      C-Cell, Hyperplasia                  |          2                                                               |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |__________________________________________________________________________|             
   Peritoneum                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  27                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 7| 7| 7| 7| 6| 7| 7| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 8| 2| 2| 2| 2| 2| 4| 2| 2| 7| 7| 5| 5| 2| 2| 2| 2| 2| 2| 1| 2| 2| 0| 0| 1|             
                                           | 1| 8| 7| 8| 8| 8| 2| 8| 6| 4| 7| 3| 3| 1| 8| 8| 9| 6| 9| 6| 9| 8| 2| 9| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
      Cyst                                 |                                                             3            |             
      Hyperplasia                          |          2                                                               |             
                                           |__________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 | 4                                                        4               |             
                                           |__________________________________________________________________________|             
   Oviduct                                 |                                                                          |             
                                           |__________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                               4                                          |             
      Endometrium, Hyperplasia             |                                                                   2      |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node                              |                   +                                                      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | M  M  M  +  M  M  M  M  M  M  M  +  M  M  M  M  M  +  M  M  M  M  M  +  M|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  +  M  M  M  M  M  M  M|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | M  +  +  +  +  M  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Accessory Spleen                     |                                                                          |             
      Hemorrhage                           |                                                                   4      |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  28                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 7| 7| 7| 7| 6| 7| 7| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 8| 2| 2| 2| 2| 2| 4| 2| 2| 7| 7| 5| 5| 2| 2| 2| 2| 2| 2| 1| 2| 2| 0| 0| 1|             
                                           | 1| 8| 7| 8| 8| 8| 2| 8| 6| 4| 7| 3| 3| 1| 8| 8| 9| 6| 9| 6| 9| 8| 2| 9| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         |             +           +  +                    +                    +   |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Compression                          |       3                                4           4                    4|             
      Gliosis                              |                                                                          |             
      Hemorrhage                           |                         3  4     4                 3              4     4|             
      Necrosis                             |                            4                                             |             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        |             +           +  +                    +                        |             
                                           |__________________________________________________________________________|             
   Spinal Cord                             |             +           +  +                    +                        |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |       4                          4                                       |             
      Inflammation, Suppurative            |                                                                          |             
      Epiglottis, Hyperplasia              |                                                                          |             
      Epiglottis, Metaplasia, Squamous     |                            2                                             |             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |             3                                                            |             
      Inflammation, Chronic                |       1                                      2     1                 3   |             
      Inflammation, Granulomatous          |             3                                                            |             
      Alveolar Epithelium, Hyperplasia     |                   3                          1                           |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Histiocyte                      |          1                                      1                        |             
      Alveolus, Pigmentation               |                                                                          |             
      Bronchiole, Hyperplasia              |                                                                          |             
      Interstitium, Fibrosis               |                   3                                2                     |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |                                  3                                       |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  29                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 7| 7| 7| 7| 6| 7| 7| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 8| 2| 2| 2| 2| 2| 4| 2| 2| 7| 7| 5| 5| 2| 2| 2| 2| 2| 2| 1| 2| 2| 0| 0| 1|             
                                           | 1| 8| 7| 8| 8| 8| 2| 8| 6| 4| 7| 3| 3| 1| 8| 8| 9| 6| 9| 6| 9| 8| 2| 9| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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                 |                                                                          |             
      Inflammation, Suppurative            |                                  1              1              1         |             
      Goblet Cell, Hyperplasia             |                                                 2                        |             
      Nasolacrimal Duct, Inflammation,     |                                                                          |             
           Suppurative                     |                   1     1                                                |             
      Olfactory Epithelium, Degeneration,  |                                                                          |             
           Hyaline                         |                            2                                             |             
      Respiratory Epithelium, Degeneration,|                                                                          |             
           Hyaline                         |                   1           1           2        3                     |             
      Respiratory Epithelium, Hyperplasia  |                                                                          |             
                                           |__________________________________________________________________________|             
   Pleura                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrosis                             |       1                                            1                    1|             
      Inflammation, Chronic                |                                                                          |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Ear                                     |                                              +           +               |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
      Inflammation, Suppurative            |                      1                                                   |             
      Cornea, Inflammation, Suppurative    |                   3                                                      |             
      Lens, Cataract                       | 2                    3                                                  3|             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Zymbal's Gland                          |                   +                             +                        |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Nephropathy                          |       2     2  2  2  1  1  2  1  1     1  1  1  2     1  1  1  1  1     1|             
      Papilla, Mineralization              |                                                                         1|             
      Pelvis, Transitional Epithelium,     |                                                                          |             
           Mineralization                  |                1        1                                1               |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                             Page  30                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 5| 7| 6| 7| 7| 5| 7| 7| 7| 6| 7| 7| 5| 7| 6| 6| 7| 7| 7| 5| 4| 6| 7|            |
                             DAY ON TEST   | 2| 3| 4| 2| 8| 2| 2| 8| 2| 2| 2| 4| 2| 2| 9| 2| 3| 1| 2| 2| 2| 1| 8| 4| 2|            |
                                           | 8| 7| 6| 9| 4| 8| 9| 2| 9| 9| 9| 2| 8| 8| 0| 7| 6| 4| 8| 9| 8| 3| 9| 3| 8|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Basophilic Focus                     |          X     X  X                 X     X  X     X  X  X  X            |     26     |
      Clear Cell Focus                     |                X              X           X  X     X                    X|     11     |
      Eosinophilic Focus                   |                                                                          |      1     |
      Hepatodiaphragmatic Nodule           |             4  4                          4                              |      9  4.0|
      Necrosis                             |                                                 4                        |      2  3.0|
      Vacuolization Cytoplasmic            |    3                             4                                       |      5  2.8|
      Hepatocyte, Regeneration             |                                              2                           |      2  3.0|
                                           |__________________________________________________________________________|____________|
   Mesentery                               | +                 +     +              +  +                    +         |  15        |
      Inflammation, Granulomatous          |                                                                          |      1  2.0|
      Necrosis                             | 3                 3     3              3  3                    3         |     15  3.0|
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Acinus, Atrophy                      |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  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  31                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 5| 7| 6| 7| 7| 5| 7| 7| 7| 6| 7| 7| 5| 7| 6| 6| 7| 7| 7| 5| 4| 6| 7|            |
                             DAY ON TEST   | 2| 3| 4| 2| 8| 2| 2| 8| 2| 2| 2| 4| 2| 2| 9| 2| 3| 1| 2| 2| 2| 1| 8| 4| 2|            |
                                           | 8| 7| 6| 9| 4| 8| 9| 2| 9| 9| 9| 2| 8| 8| 0| 7| 6| 4| 8| 9| 8| 3| 9| 3| 8|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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                  |                                                                          |            |
      Hyperplasia, Squamous                |                                                                          |      2  2.5|
      Ulcer                                |                                  4                                       |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Tongue                                  |             +                                                            |   3        |
      Epithelium, Hyperplasia              |             2                                                            |      3  2.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       |                2                                3                        |      3  2.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                   2                                                      |      1  2.0|
      Vacuolization Cytoplasmic            |    2     1              4        2     3        4     3        2         |     13  2.6|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |    4                                         4                          2|      4  3.3|
      Hemorrhage                           |                                                                          |      2  3.5|
      Hyperplasia                          |                3        4  4                                2            |      8  3.3|
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      C-Cell, Hyperplasia                  |                      4                                                   |      2  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: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 5| 7| 6| 7| 7| 5| 7| 7| 7| 6| 7| 7| 5| 7| 6| 6| 7| 7| 7| 5| 4| 6| 7|            |
                             DAY ON TEST   | 2| 3| 4| 2| 8| 2| 2| 8| 2| 2| 2| 4| 2| 2| 9| 2| 3| 1| 2| 2| 2| 1| 8| 4| 2|            |
                                           | 8| 7| 6| 9| 4| 8| 9| 2| 9| 9| 9| 2| 8| 8| 0| 7| 6| 4| 8| 9| 8| 3| 9| 3| 8|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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|            |
 _____________________________________________________________________________________________________________________|____________|
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Peritoneum                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |                                                                          |      1  3.0|
      Hyperplasia                          |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |    4  3           1              4                 4                     |      7  3.4|
                                           |__________________________________________________________________________|____________|
   Oviduct                                 | +                                                                        |   1        |
                                           |__________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemorrhage                           |                                                                          |      1  4.0|
      Endometrium, Hyperplasia             |                                        4                                2|      3  2.7|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |                                                                      +   |   2        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | M  M  M  M  +  +  M  M  M  M  M  M  +  M  M  +  M  M  M  M  M  M  M  M  M|   8        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  +  M|   2        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  46        |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Accessory Spleen                     |                X                                                         |      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  33                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 5| 7| 6| 7| 7| 5| 7| 7| 7| 6| 7| 7| 5| 7| 6| 6| 7| 7| 7| 5| 4| 6| 7|            |
                             DAY ON TEST   | 2| 3| 4| 2| 8| 2| 2| 8| 2| 2| 2| 4| 2| 2| 9| 2| 3| 1| 2| 2| 2| 1| 8| 4| 2|            |
                                           | 8| 7| 6| 9| 4| 8| 9| 2| 9| 9| 9| 2| 8| 8| 0| 7| 6| 4| 8| 9| 8| 3| 9| 3| 8|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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               |                                                                          |            |
      Hemorrhage                           |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         |             +                                            +        +      |   8        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Compression                          |       4              4           4        4        4           4         |     10  3.9|
      Gliosis                              |                                  3                                       |      1  3.0|
      Hemorrhage                           |       3     1        4                    3                              |     10  3.3|
      Necrosis                             |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        |             +                                            +               |   6        |
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             |             +                                            +               |   6        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Foreign Body                         |                                              4                           |      3  4.0|
      Inflammation, Suppurative            |                                     2                                    |      1  2.0|
      Epiglottis, Hyperplasia              |                                     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  34                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 5| 7| 6| 7| 7| 5| 7| 7| 7| 6| 7| 7| 5| 7| 6| 6| 7| 7| 7| 5| 4| 6| 7|            |
                             DAY ON TEST   | 2| 3| 4| 2| 8| 2| 2| 8| 2| 2| 2| 4| 2| 2| 9| 2| 3| 1| 2| 2| 2| 1| 8| 4| 2|            |
                                           | 8| 7| 6| 9| 4| 8| 9| 2| 9| 9| 9| 2| 8| 8| 0| 7| 6| 4| 8| 9| 8| 3| 9| 3| 8|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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                 |                                                                          |            |
      Epiglottis, Metaplasia, Squamous     |                                     1                                    |      2  1.5|
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Foreign Body                         |                                                                          |      1  3.0|
      Inflammation, Chronic                |                            2                 2  2                        |      7  1.9|
      Inflammation, Granulomatous          |                                                                          |      1  3.0|
      Alveolar Epithelium, Hyperplasia     |                                                                          |      2  2.0|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Histiocyte                      |          1                 2                    2                        |      5  1.4|
      Alveolus, Pigmentation               |                                                 2                        |      1  2.0|
      Bronchiole, Hyperplasia              |                                              3              2            |      2  2.5|
      Interstitium, Fibrosis               |                                                                          |      2  2.5|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Foreign Body                         | 3                                                                        |      2  3.0|
      Inflammation, Suppurative            | 1                                               1        2               |      6  1.2|
      Goblet Cell, Hyperplasia             |                                                          2               |      2  2.0|
      Nasolacrimal Duct, Inflammation,     |                                                                          |            |
           Suppurative                     |                                                                          |      2  1.0|
      Olfactory Epithelium, Degeneration,  |                                                                          |            |
           Hyaline                         |                                                                          |      1  2.0|
      Respiratory Epithelium, Degeneration,|                                                                          |            |
           Hyaline                         |       2           3                                   2  2               |      8  2.0|
      Respiratory Epithelium, Hyperplasia  |                                        3                 2               |      2  2.5|
                                           |__________________________________________________________________________|____________|
   Pleura                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrosis                             |                            2                                             |      4  1.3|
      Inflammation, Chronic                |                                              1                           |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Ear                                     |                                                                          |   2        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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  35                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 5| 7| 6| 7| 7| 5| 7| 7| 7| 6| 7| 7| 5| 7| 6| 6| 7| 7| 7| 5| 4| 6| 7|            |
                             DAY ON TEST   | 2| 3| 4| 2| 8| 2| 2| 8| 2| 2| 2| 4| 2| 2| 9| 2| 3| 1| 2| 2| 2| 1| 8| 4| 2|            |
                                           | 8| 7| 6| 9| 4| 8| 9| 2| 9| 9| 9| 2| 8| 8| 0| 7| 6| 4| 8| 9| 8| 3| 9| 3| 8|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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              |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Inflammation, Suppurative            |                                                                   4      |      2  2.5|
      Cornea, Inflammation, Suppurative    |                                                                          |      1  3.0|
      Lens, Cataract                       |                                              4                           |      4  3.0|
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Zymbal's Gland                          |                +                                                         |   3        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Nephropathy                          | 2  1     1  1  2     3  3  1  1  2  2  2  2  1  4  1           1     1  2|     38  1.5|
      Papilla, Mineralization              |                1                                1                        |      3  1.0|
      Pelvis, Transitional Epithelium,     |                                                                          |            |
           Mineralization                  |                1                 1  2           1                        |      7  1.1|
                                           |__________________________________________________________________________|____________|
   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  36                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 4| 7| 7| 4| 6| 7| 7| 7| 7| 7| 7| 6| 7| 7| 3| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 8| 2| 2| 9| 9| 2| 2| 2| 2| 2| 2| 8| 2| 2| 9| 2| 2| 2| 2|             
                                           | 6| 9| 8| 8| 3| 8| 9| 9| 9| 9| 5| 9| 8| 8| 9| 9| 9| 1| 8| 9| 8| 9| 9| 7| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     |       X  X     X     X  X        X        X  X  X     X  X     X  X  X  X|             
      Clear Cell Focus                     |    X                 X              X        X  X                        |             
      Eosinophilic Focus                   |                                                                          |             
      Hepatodiaphragmatic Nodule           |                                           4                          4   |             
      Necrosis                             |                               2                                          |             
      Vacuolization Cytoplasmic            |                               2           2              2               |             
      Hepatocyte, Regeneration             |                                                                          |             
                                           |__________________________________________________________________________|             
   Mesentery                               |       +  +              +                 +  +  +                       +|             
      Necrosis                             |       3  3              3                 3  3  3                       3|             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |       3                                                                  |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ulcer                                | 4                                                                        |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Tongue                                  |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  37                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 4| 7| 7| 4| 6| 7| 7| 7| 7| 7| 7| 6| 7| 7| 3| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 8| 2| 2| 9| 9| 2| 2| 2| 2| 2| 2| 8| 2| 2| 9| 2| 2| 2| 2|             
                                           | 6| 9| 8| 8| 3| 8| 9| 9| 9| 9| 5| 9| 8| 8| 9| 9| 9| 1| 8| 9| 8| 9| 9| 7| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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                  |                                                                          |             
      Epithelium, Hyperplasia              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       |                                                       2                  |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Vacuolization Cytoplasmic            |                                        1  2     3  1              1      |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Necrosis                             |                                                                          |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          | 4                                                                        |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                               4        1                                 |             
      Hemorrhage                           |                      3                                                   |             
      Hyperplasia                          |    4                                      3  4              2  4         |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                     2                                    |             
      C-Cell, Hyperplasia                  |       1                       4              4  3                        |             
      Follicular Cell, Hyperplasia         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |__________________________________________________________________________|             
   Peritoneum                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Tissue NOS                              |                                              +                           |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  38                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 4| 7| 7| 4| 6| 7| 7| 7| 7| 7| 7| 6| 7| 7| 3| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 8| 2| 2| 9| 9| 2| 2| 2| 2| 2| 2| 8| 2| 2| 9| 2| 2| 2| 2|             
                                           | 6| 9| 8| 8| 3| 8| 9| 9| 9| 9| 5| 9| 8| 8| 9| 9| 9| 1| 8| 9| 8| 9| 9| 7| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |          2                                                               |             
      Hyperplasia                          |                                  4                                       |             
                                           |__________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 | 4                                      3              4                  |             
                                           |__________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                               4                             4            |             
      Necrosis                             |                                                                          |             
      Thrombosis                           |                                                                          |             
      Endometrium, Hyperplasia             |                                           1              2               |             
      Myometrium, Hyperplasia              |                                                                          |             
                                           |__________________________________________________________________________|             
   Vagina                                  |                                                                          |             
      Muscularis, Hyperplasia              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Myelofibrosis                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node                              |             +              +                                             |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | M  +  M  M  +  M  M  M  M  +  M  M  +  M  +  M  M  M  M  M  M  M  M  +  M|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | 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|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Accessory Spleen                     |                                                                          |             
      Necrosis                             |             4                                                            |             
                                           |__________________________________________________________________________|             
   Thymus                                  | M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  39                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 4| 7| 7| 4| 6| 7| 7| 7| 7| 7| 7| 6| 7| 7| 3| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 8| 2| 2| 9| 9| 2| 2| 2| 2| 2| 2| 8| 2| 2| 9| 2| 2| 2| 2|             
                                           | 6| 9| 8| 8| 3| 8| 9| 9| 9| 9| 5| 9| 8| 8| 9| 9| 9| 1| 8| 9| 8| 9| 9| 7| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Galactocele                          |                                                                X         |             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst Epithelial Inclusion            |                                                                          |             
      Ulcer                                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         |             +  +     +                             +  +  +               |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Compression                          | 4              3  4                                   4  3               |             
      Hemorrhage                           | 3                                                        2               |             
      Necrosis                             |                                                                          |             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        |             +  +     +                             +  +  +               |             
                                           |__________________________________________________________________________|             
   Spinal Cord                             |             +  +     +                             +  +  +               |             
      Cyst Epithelial Inclusion            |                                                    3                     |             
      Hemorrhage                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |             4                                                            |             
      Inflammation, Suppurative            |             2                                                            |             
      Epiglottis, Metaplasia, Squamous     |                                                                         1|             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                                                          |             
      Inflammation, Chronic                |    1                                                  1                  |             
      Alveolar Epithelium, Hyperplasia     |                      1                                               1   |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  40                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 4| 7| 7| 4| 6| 7| 7| 7| 7| 7| 7| 6| 7| 7| 3| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 8| 2| 2| 9| 9| 2| 2| 2| 2| 2| 2| 8| 2| 2| 9| 2| 2| 2| 2|             
                                           | 6| 9| 8| 8| 3| 8| 9| 9| 9| 9| 5| 9| 8| 8| 9| 9| 9| 1| 8| 9| 8| 9| 9| 7| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
      Alveolar Epithelium, Metaplasia,     |                                                                          |             
           Squamous                        |                      2                                                   |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Histiocyte                      |       1  1           1  1                             1        1         |             
      Bronchiole, Hyperplasia              |       3                          2                                       |             
      Interstitium, Fibrosis               |                                                                          |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |                                                                          |             
      Goblet Cell, Hyperplasia             |                                                                          |             
      Olfactory Epithelium, Degeneration,  |                                                                          |             
           Hyaline                         |                                                                          |             
      Respiratory Epithelium, Degeneration,|                                                                          |             
           Hyaline                         |                3  2              2  1              2                    2|             
                                           |__________________________________________________________________________|             
   Pleura                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrosis                             |       1              1                                                   |             
      Inflammation, Chronic                |                               1                                          |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lens, Cataract                       |    2                                                                    4|             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Zymbal's Gland                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infarct                              |                                                    X                     |             
      Nephropathy                          | 2  2  3  1  2  1     1  2  1  1  3  3  2  1  2  1  1  3  4     2     2  3|             
      Papilla, Mineralization              |                            1                    1                        |             
      Pelvis, Transitional Epithelium,     |                                                                          |             
           Hyperplasia                     |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  41                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 4| 7| 7| 4| 6| 7| 7| 7| 7| 7| 7| 6| 7| 7| 3| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 8| 2| 2| 9| 9| 2| 2| 2| 2| 2| 2| 8| 2| 2| 9| 2| 2| 2| 2|             
                                           | 6| 9| 8| 8| 3| 8| 9| 9| 9| 9| 5| 9| 8| 8| 9| 9| 9| 1| 8| 9| 8| 9| 9| 7| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
      Pelvis, Transitional Epithelium,     |                                                                          |             
           Mineralization                  |                                                                   1      |             
      Renal Tubule, Cyst                   |                                                                          |             
      Renal Tubule, Hyperplasia            |                                                                3         |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  42                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 5| 7| 7| 7| 6| 6| 3| 7| 7| 6| 4| 7| 7| 7| 5| 7| 6| 6| 7| 7| 6| 6| 7|            |
                             DAY ON TEST   | 2| 2| 0| 2| 2| 2| 5| 8| 6| 2| 2| 9| 5| 2| 2| 2| 4| 2| 6| 3| 2| 2| 9| 9| 2|            |
                                           | 8| 9| 6| 9| 8| 9| 1| 1| 4| 7| 8| 1| 4| 8| 9| 8| 8| 9| 7| 7| 9| 9| 2| 5| 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     |
   FISCHER 344 RATS 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        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Basophilic Focus                     |          X  X     X  X                    X                              |     20     |
      Clear Cell Focus                     |                      X                 X                                 |      7     |
      Eosinophilic Focus                   |                                  X                    X                  |      2     |
      Hepatodiaphragmatic Nodule           |                         4                          4              4      |      5  4.0|
      Necrosis                             |                                     2           2                        |      3  2.0|
      Vacuolization Cytoplasmic            |                                     2                                    |      4  2.0|
      Hepatocyte, Regeneration             |                                                             4        4   |      2  4.0|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |          +              +  +        +  +     +        +     +            |  15        |
      Necrosis                             |          3              3  3           3     3        2     3            |     14  2.9|
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Ulcer                                |                                                                          |      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  43                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 5| 7| 7| 7| 6| 6| 3| 7| 7| 6| 4| 7| 7| 7| 5| 7| 6| 6| 7| 7| 6| 6| 7|            |
                             DAY ON TEST   | 2| 2| 0| 2| 2| 2| 5| 8| 6| 2| 2| 9| 5| 2| 2| 2| 4| 2| 6| 3| 2| 2| 9| 9| 2|            |
                                           | 8| 9| 6| 9| 8| 9| 1| 1| 4| 7| 8| 1| 4| 8| 9| 8| 8| 9| 7| 7| 9| 9| 2| 5| 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     |
   FISCHER 344 RATS 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, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Tongue                                  |                   +                                            +         |   2        |
      Epithelium, Hyperplasia              |                   3                                            2         |      2  2.5|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       |                                                    2                     |      2  2.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Vacuolization Cytoplasmic            |    4        4                    1        1                              |      9  2.0|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Necrosis                             |                                                 4                        |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |             4                                                            |      3  3.0|
      Hemorrhage                           |                                                       3  4               |      3  3.3|
      Hyperplasia                          |                            2     1                                4  4  4|     10  3.2|
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |                                                                          |      1  2.0|
      C-Cell, Hyperplasia                  |                                     1                                    |      5  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  44                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 5| 7| 7| 7| 6| 6| 3| 7| 7| 6| 4| 7| 7| 7| 5| 7| 6| 6| 7| 7| 6| 6| 7|            |
                             DAY ON TEST   | 2| 2| 0| 2| 2| 2| 5| 8| 6| 2| 2| 9| 5| 2| 2| 2| 4| 2| 6| 3| 2| 2| 9| 9| 2|            |
                                           | 8| 9| 6| 9| 8| 9| 1| 1| 4| 7| 8| 1| 4| 8| 9| 8| 8| 9| 7| 7| 9| 9| 2| 5| 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     |
   FISCHER 344 RATS 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                   |                                                                          |            |
      Follicular Cell, Hyperplasia         |                   3                                                      |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Peritoneum                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Tissue NOS                              |                                              +                           |   2        |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |                                                                          |      1  2.0|
      Hyperplasia                          |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |                                           4                              |      4  3.8|
                                           |__________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemorrhage                           |                                                                          |      2  4.0|
      Necrosis                             |                4                                                         |      1  4.0|
      Thrombosis                           |                4                                                         |      1  4.0|
      Endometrium, Hyperplasia             | 4                                                                        |      3  2.3|
      Myometrium, Hyperplasia              |                                                       3                  |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Vagina                                  |                                                       +                  |   1        |
      Muscularis, Hyperplasia              |                                                       4                  |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Myelofibrosis                        |                                  3                                       |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |                                  +                                       |   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  45                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 5| 7| 7| 7| 6| 6| 3| 7| 7| 6| 4| 7| 7| 7| 5| 7| 6| 6| 7| 7| 6| 6| 7|            |
                             DAY ON TEST   | 2| 2| 0| 2| 2| 2| 5| 8| 6| 2| 2| 9| 5| 2| 2| 2| 4| 2| 6| 3| 2| 2| 9| 9| 2|            |
                                           | 8| 9| 6| 9| 8| 9| 1| 1| 4| 7| 8| 1| 4| 8| 9| 8| 8| 9| 7| 7| 9| 9| 2| 5| 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     |
   FISCHER 344 RATS 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, Bronchial                   | M  M  +  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|   7        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  +  M|   1        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Accessory Spleen                     |                                                             X            |      1     |
      Necrosis                             |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Galactocele                          |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst Epithelial Inclusion            |                                        4                                 |      1  4.0|
      Ulcer                                |                1                       3                                 |      2  2.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         |          +  +  +  +                    +        +     +  +               |  14        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Compression                          |                   4                                   4                  |      7  3.7|
      Hemorrhage                           |                   2                                   3  4               |      5  2.8|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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  46                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 5| 7| 7| 7| 6| 6| 3| 7| 7| 6| 4| 7| 7| 7| 5| 7| 6| 6| 7| 7| 6| 6| 7|            |
                             DAY ON TEST   | 2| 2| 0| 2| 2| 2| 5| 8| 6| 2| 2| 9| 5| 2| 2| 2| 4| 2| 6| 3| 2| 2| 9| 9| 2|            |
                                           | 8| 9| 6| 9| 8| 9| 1| 1| 4| 7| 8| 1| 4| 8| 9| 8| 8| 9| 7| 7| 9| 9| 2| 5| 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     |
   FISCHER 344 RATS 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|            |
 _____________________________________________________________________________________________________________________|____________|
 NERVOUS SYSTEM - cont                     |                                                                          |            |
      Necrosis                             |                                                       4  4               |      2  4.0|
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        |          +  +  +  +                    +        +     +  +               |  14        |
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             |          +  +  +  +                    +        +     +  +               |  14        |
      Cyst Epithelial Inclusion            |                                                                          |      1  3.0|
      Hemorrhage                           |                                                 2                        |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Foreign Body                         |                                                 4                        |      2  4.0|
      Inflammation, Suppurative            |                                                 2                        |      2  2.0|
      Epiglottis, Metaplasia, Squamous     |                                                 2                        |      2  1.5|
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemorrhage                           |                                                          2               |      1  2.0|
      Inflammation, Chronic                |                                  2                             1         |      4  1.3|
      Alveolar Epithelium, Hyperplasia     |          2           2           1                                1      |      6  1.3|
      Alveolar Epithelium, Metaplasia,     |                                                                          |            |
           Squamous                        |                                                                          |      1  2.0|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Histiocyte                      |    1     1           1                                   1        2      |     11  1.1|
      Bronchiole, Hyperplasia              |                                                                   2      |      3  2.3|
      Interstitium, Fibrosis               |                                                                   1      |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Foreign Body                         |                                                             3            |      1  3.0|
      Goblet Cell, Hyperplasia             |                                                             2            |      1  2.0|
      Olfactory Epithelium, Degeneration,  |                                                                          |            |
           Hyaline                         |                   1                                      2               |      2  1.5|
      Respiratory Epithelium, Degeneration,|                                                                          |            |
           Hyaline                         |             3                                               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  47                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 5| 7| 7| 7| 6| 6| 3| 7| 7| 6| 4| 7| 7| 7| 5| 7| 6| 6| 7| 7| 6| 6| 7|            |
                             DAY ON TEST   | 2| 2| 0| 2| 2| 2| 5| 8| 6| 2| 2| 9| 5| 2| 2| 2| 4| 2| 6| 3| 2| 2| 9| 9| 2|            |
                                           | 8| 9| 6| 9| 8| 9| 1| 1| 4| 7| 8| 1| 4| 8| 9| 8| 8| 9| 7| 7| 9| 9| 2| 5| 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     |
   FISCHER 344 RATS 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                 |                                                                          |            |
   Pleura                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrosis                             |    1                                1                          1         |      5  1.0|
      Inflammation, Chronic                |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +|  49        |
      Lens, Cataract                       |                4                                               2         |      4  3.0|
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Zymbal's Gland                          |                +                                                         |   1        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Infarct                              |                                                                          |      1     |
      Nephropathy                          | 1  3     2  1  2  3  1     2  3  1     2  2  2  1  1  2  2  3  2  1  1  2|     44  1.9|
      Papilla, Mineralization              |             1                                                            |      3  1.0|
      Pelvis, Transitional Epithelium,     |                                                                          |            |
           Hyperplasia                     |                1                                                         |      1  1.0|
      Pelvis, Transitional Epithelium,     |                                                                          |            |
           Mineralization                  |    1                                                                     |      2  1.0|
      Renal Tubule, Cyst                   |                   X                                                      |      1     |
      Renal Tubule, Hyperplasia            |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   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  48                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 1| 2| 7| 2| 2| 2| 2| 2| 2| 8| 2| 0| 2| 0| 2| 2| 2| 2| 2| 2|             
                                           | 6| 6| 7| 6| 6| 3| 7| 9| 6| 7| 6| 6| 6| 9| 7| 7| 1| 7| 2| 6| 7| 6| 3| 6| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          | 2                                                                        |             
      Basophilic Focus                     |          X  X                       X                    X     X         |             
      Clear Cell Focus                     |    X  X           X                 X        X           X  X            |             
      Degeneration, Cystic                 |          2                                                               |             
      Eosinophilic Focus                   |                                              X                           |             
      Hepatodiaphragmatic Nodule           |                                           4                             4|             
      Mixed Cell Focus                     |                                                                X         |             
      Necrosis                             |                                                                          |             
      Vacuolization Cytoplasmic            |          3     3        1                                                |             
      Bile Duct, Cyst                      |                                                                          |             
      Centrilobular, Necrosis              |                                                                          |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                         +              +  +  +           +               |             
      Necrosis                             |                         3              2  3  3           2               |             
                                           |__________________________________________________________________________|             
   Oral Mucosa                             |                                                                          |             
      Pharyngeal, Hyperplasia, Squamous    |                                                                          |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Acinus, Atrophy                      |       3                                      1                           |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  49                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 1| 2| 7| 2| 2| 2| 2| 2| 2| 8| 2| 0| 2| 0| 2| 2| 2| 2| 2| 2|             
                                           | 6| 6| 7| 6| 6| 3| 7| 9| 6| 7| 6| 6| 6| 9| 7| 7| 1| 7| 2| 6| 7| 6| 3| 6| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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                  |                                                                          |             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ulcer                                |                4                                                         |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Erosion                              |                                        2                                 |             
                                           |__________________________________________________________________________|             
   Tongue                                  |                                     +                                    |             
      Epithelium, Hyperplasia              |                                     2                                    |             
                                           |__________________________________________________________________________|             
   Tooth                                   |                                                                          |             
      Peridontal Tissue, Inflammation      |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       | 1     2           3              2                 2           2  2      |             
      Atrium, Thrombosis                   |                                                                          |             
      Myocardium, Mineralization           |                   2                                                      |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
      Vacuolization Cytoplasmic            |       1                          2                 4                     |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
      Hemorrhage                           |                                                                          |             
      Hyperplasia                          | 2     2  2        2              2  1     3        3                     |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  50                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 1| 2| 7| 2| 2| 2| 2| 2| 2| 8| 2| 0| 2| 0| 2| 2| 2| 2| 2| 2|             
                                           | 6| 6| 7| 6| 6| 3| 7| 9| 6| 7| 6| 6| 6| 9| 7| 7| 1| 7| 2| 6| 7| 6| 3| 6| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
      Atrophy                              |                                                                          |             
      Cyst                                 |                                                                          |             
      Hemorrhage                           |                4                                                         |             
      Hyperplasia                          |                   4                 4                       4            |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      C-Cell, Hyperplasia                  | 3                                         1           1                  |             
      Follicle, Cyst                       |                                              2                           |             
      Follicular Cell, Hyperplasia         |    1                                                                     |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |__________________________________________________________________________|             
   Peritoneum                              | +  +     +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Tissue NOS                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                                          |             
      Hyperplasia                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            |                   3                                               3      |             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Germinal Epithelium, Atrophy         |                      4                                         4  4      |             
      Interstitial Cell, Hyperplasia       |    3                                                                     |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node                              |       +                                +                                +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  51                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 1| 2| 7| 2| 2| 2| 2| 2| 2| 8| 2| 0| 2| 0| 2| 2| 2| 2| 2| 2|             
                                           | 6| 6| 7| 6| 6| 3| 7| 9| 6| 7| 6| 6| 6| 9| 7| 7| 1| 7| 2| 6| 7| 6| 3| 6| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
      Deep Cervical, Infiltration Cellular,|                                                                          |             
           Histiocyte                      |       2                                                                  |             
      Pancreatic, Ectasia                  |                                                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | M  M  +  M  M  M  M  M  M  M  +  M  M  +  M  +  +  M  M  M  M  +  +  M  M|             
      Angiectasis                          |                                                                   4      |             
      Ectasia                              |                                                                          |             
      Infiltration Cellular, Histiocyte    |       2                                                                  |             
      Pigmentation                         |                                                                3         |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | M  M  M  M  +  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  M  +  +  +  M  +  +  +  +  +  M  +  +  +  +  +  +  +  +  M  M  +  M|             
      Hemorrhage                           |                                                                          |             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Accessory Spleen                     |                                                                      X   |             
      Fibrosis                             |                                        4                                 |             
      Hemorrhage                           |                                        4        4                        |             
      Necrosis                             |                                        4        4                        |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|             
      Galactocele                          | 4                                2                                       |             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst Epithelial Inclusion            |                               4                                4         |             
      Hyperkeratosis                       |                                                                          |             
      Sebaceous Gland, Hyperplasia         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  52                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 1| 2| 7| 2| 2| 2| 2| 2| 2| 8| 2| 0| 2| 0| 2| 2| 2| 2| 2| 2|             
                                           | 6| 6| 7| 6| 6| 3| 7| 9| 6| 7| 6| 6| 6| 9| 7| 7| 1| 7| 2| 6| 7| 6| 3| 6| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM - cont             |                                                                          |             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperostosis                         |                                                 2                        |             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Compression                          |    2     4           4                                4        2         |             
      Hemorrhage                           |                                           3           4           4     4|             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Spinal Cord                             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |                               4                                         4|             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                                                          |             
      Inflammation, Chronic                | 1           2                                                            |             
      Alveolar Epithelium, Hyperplasia     |    4                       1                             1               |             
      Alveolar Epithelium, Metaplasia,     |                                                                          |             
           Squamous                        |                                                                          |             
      Alveolus, Emphysema                  |                                                                      3   |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Histiocyte                      | 2           2        2     2                             2     2         |             
      Interstitium, Fibrosis               |                                                                          |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |                                                                          |             
      Inflammation, Suppurative            |       2                                                           2      |             
      Goblet Cell, Hyperplasia             |       2                                                                  |             
      Respiratory Epithelium, Hyperplasia  |       2                             2                                    |             
                                           |__________________________________________________________________________|             
   Pleura                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  53                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6|             
                             DAY ON TEST   | 2| 2| 2| 2| 2| 1| 2| 7| 2| 2| 2| 2| 2| 2| 8| 2| 0| 2| 0| 2| 2| 2| 2| 2| 2|             
                                           | 6| 6| 7| 6| 6| 3| 7| 9| 6| 7| 6| 6| 6| 9| 7| 7| 1| 7| 2| 6| 7| 6| 3| 6| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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                 |                                                                          |             
      Fibrosis                             | 1                                                              1         |             
      Inflammation, Chronic                |             2                                                  1         |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lens, Cataract                       |                                  3           3              3            |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lacrimal Gland                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Zymbal's Gland                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Nephropathy                          | 1  1        2  4  2  2  2  3  1  2  2     1  2  2  2  2  1  2  2  2  1  2|             
      Papilla, Mineralization              |                                                                          |             
      Pelvis, Transitional Epithelium,     |                                                                          |             
           Hyperplasia                     |                            1                                             |             
      Renal Tubule, Cyst                   |                                                 X                        |             
      Renal Tubule, Hyperplasia            |                                                    2                     |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Calculus Micro Observation Only      | 2                                                                        |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  54                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 5| 7| 7| 7| 7| 7| 7| 5| 7| 7| 6| 5| 7| 6| 4| 7| 7| 4| 7| 5| 7| 7| 7|            |
                             DAY ON TEST   | 2| 8| 9| 2| 2| 2| 2| 2| 2| 8| 2| 0| 7| 0| 2| 7| 9| 2| 2| 6| 2| 5| 2| 2| 2|            |
                                           | 7| 7| 2| 6| 6| 7| 7| 6| 7| 8| 7| 2| 1| 5| 7| 9| 2| 7| 6| 8| 6| 4| 7| 7| 6|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Angiectasis                          |                                                                          |      1  2.0|
      Basophilic Focus                     | X           X        X                       X        X     X            |     11     |
      Clear Cell Focus                     | X        X                                         X  X           X  X  X|     14     |
      Degeneration, Cystic                 |                                                                          |      1  2.0|
      Eosinophilic Focus                   |                               X                                          |      2     |
      Hepatodiaphragmatic Nodule           |                                                                         4|      3  4.0|
      Mixed Cell Focus                     |                                                                          |      1     |
      Necrosis                             |                                     4                                    |      1  4.0|
      Vacuolization Cytoplasmic            |                            3                                             |      4  2.5|
      Bile Duct, Cyst                      |                      3                                                   |      1  3.0|
      Centrilobular, Necrosis              |                            2                                             |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Mesentery                               | +           +                             +     +                       +|  10        |
      Necrosis                             | 3           3                             3     3                       3|     10  2.8|
                                           |__________________________________________________________________________|____________|
   Oral Mucosa                             |                                  +  +                                    |   2        |
      Pharyngeal, Hyperplasia, Squamous    |                                     4                                    |      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  55                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 5| 7| 7| 7| 7| 7| 7| 5| 7| 7| 6| 5| 7| 6| 4| 7| 7| 4| 7| 5| 7| 7| 7|            |
                             DAY ON TEST   | 2| 8| 9| 2| 2| 2| 2| 2| 2| 8| 2| 0| 7| 0| 2| 7| 9| 2| 2| 6| 2| 5| 2| 2| 2|            |
                                           | 7| 7| 2| 6| 6| 7| 7| 6| 7| 8| 7| 2| 1| 5| 7| 9| 2| 7| 6| 8| 6| 4| 7| 7| 6|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Acinus, Atrophy                      | 3                 1                                                      |      4  2.0|
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Ulcer                                |    3                       4                                             |      3  3.7|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Erosion                              |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Tongue                                  |                                                                          |   1        |
      Epithelium, Hyperplasia              |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Tooth                                   |                                     +                                    |   1        |
      Peridontal Tissue, Inflammation      |                                     4                                    |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       |                2     2                       1     2  1           3     3|     14  2.0|
      Atrium, Thrombosis                   |       4                    4                                             |      2  4.0|
      Myocardium, Mineralization           |                                                                          |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |                   4                                                      |      1  4.0|
      Vacuolization Cytoplasmic            |    1           1           2        2                                    |      7  1.9|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |          4                                                               |      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  56                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 5| 7| 7| 7| 7| 7| 7| 5| 7| 7| 6| 5| 7| 6| 4| 7| 7| 4| 7| 5| 7| 7| 7|            |
                             DAY ON TEST   | 2| 8| 9| 2| 2| 2| 2| 2| 2| 8| 2| 0| 7| 0| 2| 7| 9| 2| 2| 6| 2| 5| 2| 2| 2|            |
                                           | 7| 7| 2| 6| 6| 7| 7| 6| 7| 8| 7| 2| 1| 5| 7| 9| 2| 7| 6| 8| 6| 4| 7| 7| 6|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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                   |                                                                          |            |
      Hemorrhage                           |                               4                                          |      1  4.0|
      Hyperplasia                          | 1                    4     1        3                             3      |     13  2.2|
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |                   4                                                      |      1  4.0|
      Cyst                                 |                4                                                         |      1  4.0|
      Hemorrhage                           |                                  3                    3        4         |      4  3.5|
      Hyperplasia                          | 4                                                     3  3        4  4   |      8  3.8|
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      C-Cell, Hyperplasia                  |                                                                   2      |      4  1.8|
      Follicle, Cyst                       |                                                                          |      1  2.0|
      Follicular Cell, Hyperplasia         |                                                                          |      1  1.0|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Peritoneum                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Tissue NOS                              |                               +                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |                               2                                          |      1  2.0|
      Hyperplasia                          | 4                                                                        |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Suppurative            |                            3                                             |      3  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  57                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 5| 7| 7| 7| 7| 7| 7| 5| 7| 7| 6| 5| 7| 6| 4| 7| 7| 4| 7| 5| 7| 7| 7|            |
                             DAY ON TEST   | 2| 8| 9| 2| 2| 2| 2| 2| 2| 8| 2| 0| 7| 0| 2| 7| 9| 2| 2| 6| 2| 5| 2| 2| 2|            |
                                           | 7| 7| 2| 6| 6| 7| 7| 6| 7| 8| 7| 2| 1| 5| 7| 9| 2| 7| 6| 8| 6| 4| 7| 7| 6|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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|            |
 _____________________________________________________________________________________________________________________|____________|
 GENITAL SYSTEM - cont                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Germinal Epithelium, Atrophy         |    3        3  4  4           4     3        4                           |     10  3.7|
      Interstitial Cell, Hyperplasia       |                            3     3                       3               |      4  3.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |    +                          +     +              +                     |   7        |
      Deep Cervical, Infiltration Cellular,|                                                                          |            |
           Histiocyte                      |                                                                          |      1  2.0|
      Pancreatic, Ectasia                  |                                     4              3                     |      2  3.5|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | M  M  M  M  M  M  M  +  M  +  M  M  M  M  +  M  M  M  M  M  +  M  M  M  M|  11        |
      Angiectasis                          |                                                                          |      1  4.0|
      Ectasia                              |                      4     4                                3            |      3  3.7|
      Infiltration Cellular, Histiocyte    |                                                                          |      1  2.0|
      Pigmentation                         |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | 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|   1        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Lymphoid                |                                                    4                     |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  M  +  +  +  +  +  M|  41        |
      Hemorrhage                           |                                              4                           |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Accessory Spleen                     |                                                 X                        |      2     |
      Fibrosis                             |                            2                                             |      2  3.0|
      Hemorrhage                           |                                                                          |      2  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  58                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 5| 7| 7| 7| 7| 7| 7| 5| 7| 7| 6| 5| 7| 6| 4| 7| 7| 4| 7| 5| 7| 7| 7|            |
                             DAY ON TEST   | 2| 8| 9| 2| 2| 2| 2| 2| 2| 8| 2| 0| 7| 0| 2| 7| 9| 2| 2| 6| 2| 5| 2| 2| 2|            |
                                           | 7| 7| 2| 6| 6| 7| 7| 6| 7| 8| 7| 2| 1| 5| 7| 9| 2| 7| 6| 8| 6| 4| 7| 7| 6|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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               |                                                                          |            |
      Necrosis                             |    4                                                     4               |      4  4.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Galactocele                          |          4  4                          1                                 |      5  3.0|
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst Epithelial Inclusion            |                                           X                              |      3  4.0|
      Hyperkeratosis                       |                                        4                                 |      1  4.0|
      Sebaceous Gland, Hyperplasia         |                                        3                                 |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperostosis                         |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         |       +                          +                                      +|   3        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Compression                          |                                        4     4                 3         |      8  3.4|
      Hemorrhage                           |                                                                4         |      5  3.8|
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        |                                  +                                      +|   2        |
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             |                                  +                                      +|   2        |
 _____________________________________________________________________________________________________________________|            |
 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  59                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 5| 7| 7| 7| 7| 7| 7| 5| 7| 7| 6| 5| 7| 6| 4| 7| 7| 4| 7| 5| 7| 7| 7|            |
                             DAY ON TEST   | 2| 8| 9| 2| 2| 2| 2| 2| 2| 8| 2| 0| 7| 0| 2| 7| 9| 2| 2| 6| 2| 5| 2| 2| 2|            |
                                           | 7| 7| 2| 6| 6| 7| 7| 6| 7| 8| 7| 2| 1| 5| 7| 9| 2| 7| 6| 8| 6| 4| 7| 7| 6|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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 - cont                 |                                                                          |            |
      Foreign Body                         |                                                                          |      2  4.0|
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemorrhage                           |    3                       2                                             |      2  2.5|
      Inflammation, Chronic                | 2                                         3                              |      4  2.0|
      Alveolar Epithelium, Hyperplasia     |                                                                      1   |      4  1.8|
      Alveolar Epithelium, Metaplasia,     |                                                                          |            |
           Squamous                        |                                                                      1   |      1  1.0|
      Alveolus, Emphysema                  |                            2                                             |      2  2.5|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Histiocyte                      | 2  2              1                       2                              |     10  1.9|
      Interstitium, Fibrosis               | 2                                         3                              |      2  2.5|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Foreign Body                         |                                        3                                 |      1  3.0|
      Inflammation, Suppurative            |                               2        2                                 |      4  2.0|
      Goblet Cell, Hyperplasia             |                                                                          |      1  2.0|
      Respiratory Epithelium, Hyperplasia  |                               2        3                                 |      4  2.3|
                                           |__________________________________________________________________________|____________|
   Pleura                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrosis                             |                            3                                             |      3  1.7|
      Inflammation, Chronic                | 2                          2              2                 2            |      6  1.8|
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +|  49        |
      Lens, Cataract                       |       1     3  3              3                                          |      7  2.7|
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lacrimal Gland                          |       +                                                                  |   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  60                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 5| 7| 7| 7| 7| 7| 7| 5| 7| 7| 6| 5| 7| 6| 4| 7| 7| 4| 7| 5| 7| 7| 7|            |
                             DAY ON TEST   | 2| 8| 9| 2| 2| 2| 2| 2| 2| 8| 2| 0| 7| 0| 2| 7| 9| 2| 2| 6| 2| 5| 2| 2| 2|            |
                                           | 7| 7| 2| 6| 6| 7| 7| 6| 7| 8| 7| 2| 1| 5| 7| 9| 2| 7| 6| 8| 6| 4| 7| 7| 6|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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|            |
 _____________________________________________________________________________________________________________________|____________|
 SPECIAL SENSES SYSTEM - cont              |                                                                          |            |
   Zymbal's Gland                          |                            +                                             |   1        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Nephropathy                          | 4  2     2  2  1     2  4     1  2  2  2  2  1     3  2     3  2  2  3  2|     42  2.0|
      Papilla, Mineralization              |          1                                                               |      1  1.0|
      Pelvis, Transitional Epithelium,     |                                                                          |            |
           Hyperplasia                     |                                                                          |      1  1.0|
      Renal Tubule, Cyst                   |                                                                          |      1     |
      Renal Tubule, Hyperplasia            |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Calculus Micro Observation Only      |                                                                          |      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  61                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 5| 7| 7| 6| 7| 7| 7| 6| 7| 7| 3| 7| 6| 7| 7| 7| 4| 7| 6| 6| 7| 7| 4|             
                             DAY ON TEST   | 2| 2| 9| 2| 2| 7| 0| 2| 2| 6| 2| 2| 3| 2| 5| 2| 2| 2| 0| 2| 0| 3| 2| 2| 2|             
                                           | 1| 6| 5| 6| 1| 7| 5| 0| 6| 4| 6| 6| 8| 7| 4| 7| 6| 7| 5| 6| 9| 7| 6| 6| 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|             
   FISCHER 344 RATS 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                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ulcer                                |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     |          X                       X           X                       X   |             
      Clear Cell Focus                     |          X     X                 X     X     X  X  X     X               |             
      Eosinophilic Focus                   |                         X                                X           X   |             
      Hepatodiaphragmatic Nodule           |                                                          4        4      |             
      Inflammation, Granulomatous          |                                                                3         |             
      Necrosis                             |                                           4           4  2              4|             
      Vacuolization Cytoplasmic            | 2     3                                                                  |             
      Bile Duct, Hyperplasia               |             3     3                    3                                 |             
      Bile Duct, Inflammation, Suppurative |                                                       4                  |             
      Centrilobular, Necrosis              |                                                                          |             
      Hepatocyte, Regeneration             |                         4                                                |             
      Periportal, Inflammation, Chronic    |                                                                3         |             
                                           |__________________________________________________________________________|             
   Mesentery                               | +  +  +     +              +  +           +        +                     |             
      Necrosis                             | 3  3  3     3              3  3           3        3                     |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Necrosis                             |                                                       4                  |             
      Acinus, Atrophy                      |                   3                    2                                 |             
      Artery, Thrombosis                   |                                                       4                  |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  62                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 5| 7| 7| 6| 7| 7| 7| 6| 7| 7| 3| 7| 6| 7| 7| 7| 4| 7| 6| 6| 7| 7| 4|             
                             DAY ON TEST   | 2| 2| 9| 2| 2| 7| 0| 2| 2| 6| 2| 2| 3| 2| 5| 2| 2| 2| 0| 2| 0| 3| 2| 2| 2|             
                                           | 1| 6| 5| 6| 1| 7| 5| 0| 6| 4| 6| 6| 8| 7| 4| 7| 6| 7| 5| 6| 9| 7| 6| 6| 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|             
   FISCHER 344 RATS 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                  |                                                                          |             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                      4   |             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ulcer                                |                                                                          |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Erosion                              |                                                                         3|             
                                           |__________________________________________________________________________|             
   Tongue                                  |                                        +                                 |             
      Epithelium, Hyperplasia              |                                        3                                 |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       |    2                 3        2                                   2      |             
      Atrium, Thrombosis                   |             4                             4                             4|             
      Valve, Inflammation, Suppurative     |                                                                         4|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Vacuolization Cytoplasmic            |                                                 2                        |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |          3  3        2  2  2           3     1  3                    4  2|             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                              4                           |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |             3                                                            |             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                                          |             
      Hemorrhage                           |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  63                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 5| 7| 7| 6| 7| 7| 7| 6| 7| 7| 3| 7| 6| 7| 7| 7| 4| 7| 6| 6| 7| 7| 4|             
                             DAY ON TEST   | 2| 2| 9| 2| 2| 7| 0| 2| 2| 6| 2| 2| 3| 2| 5| 2| 2| 2| 0| 2| 0| 3| 2| 2| 2|             
                                           | 1| 6| 5| 6| 1| 7| 5| 0| 6| 4| 6| 6| 8| 7| 4| 7| 6| 7| 5| 6| 9| 7| 6| 6| 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
      Hyperplasia                          |                                     3  3                 2  4           2|             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      C-Cell, Hyperplasia                  |                         2                                         2      |             
      Follicle, Cyst                       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |__________________________________________________________________________|             
   Peritoneum                              | +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |       4                                                              4   |             
      Hyperplasia                          | 3                                                                        |             
                                           |__________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            |       2                                                                  |             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Germinal Epithelium, Atrophy         |                   3           4                                4  4      |             
      Interstitial Cell, Hyperplasia       |                                                       3                  |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Reticulum Cell          |                                                    4                     |             
      Myelofibrosis                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node                              |             +     +     +                                                |             
      Deep Cervical, Hemorrhage            |                         3                                                |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  M  M  M  +  M  +  +  M  +  M  M  M  M  M  M  M  M  M  M  M  M  M  M  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  64                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 5| 7| 7| 6| 7| 7| 7| 6| 7| 7| 3| 7| 6| 7| 7| 7| 4| 7| 6| 6| 7| 7| 4|             
                             DAY ON TEST   | 2| 2| 9| 2| 2| 7| 0| 2| 2| 6| 2| 2| 3| 2| 5| 2| 2| 2| 0| 2| 0| 3| 2| 2| 2|             
                                           | 1| 6| 5| 6| 1| 7| 5| 0| 6| 4| 6| 6| 8| 7| 4| 7| 6| 7| 5| 6| 9| 7| 6| 6| 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
      Ectasia                              | 4                                                                        |             
      Hemorrhage                           |                                                                         3|             
      Infiltration Cellular, Histiocyte    |                                                                          |             
      Pigmentation                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | 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|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  M  +  M  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Pigmentation                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Accessory Spleen                     |                                                                          |             
      Fibrosis                             |          3                                                              2|             
      Hemorrhage                           |                      4                                                   |             
      Necrosis                             |                   4  4                                                   |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst Epithelial Inclusion            |                               4                                          |             
      Hyperkeratosis                       |                                  4                                       |             
      Inflammation, Acute                  |                                                                          |             
      Subcutaneous Tissue, Fibrosis        |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cranium, Maxilla, Fracture           |                                                                          |             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         |       +                                +                                 |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  65                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 5| 7| 7| 6| 7| 7| 7| 6| 7| 7| 3| 7| 6| 7| 7| 7| 4| 7| 6| 6| 7| 7| 4|             
                             DAY ON TEST   | 2| 2| 9| 2| 2| 7| 0| 2| 2| 6| 2| 2| 3| 2| 5| 2| 2| 2| 0| 2| 0| 3| 2| 2| 2|             
                                           | 1| 6| 5| 6| 1| 7| 5| 0| 6| 4| 6| 6| 8| 7| 4| 7| 6| 7| 5| 6| 9| 7| 6| 6| 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Compression                          | 2        3                    3                 3              3         |             
      Hemorrhage                           |                   4                                                      |             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        |       +                                +                                 |             
                                           |__________________________________________________________________________|             
   Spinal Cord                             |       +                                +                                 |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |                            4  4              4                           |             
      Inflammation, Suppurative            |                2                    3                                    |             
      Epiglottis, Metaplasia, Squamous     |                2                                                         |             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |       2     2                                         4                 4|             
      Inflammation, Suppurative            |                2                                                        3|             
      Thrombosis                           |                                                       3                  |             
      Alveolar Epithelium, Hyperplasia     |                      1     2                    4           2            |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Histiocyte                      |       2                                   3                              |             
      Alveolus, Pigmentation               |                                           3                              |             
      Bronchiole, Alveolus, Foreign Body   |                                                                          |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |                                                 3                        |             
      Inflammation, Suppurative            | 1                                               3                        |             
      Goblet Cell, Hyperplasia             |                                                                          |             
      Nasolacrimal Duct, Inflammation,     |                                                                          |             
           Suppurative                     |                                                                          |             
      Respiratory Epithelium, Hyperplasia  |                                                                          |             
                                           |__________________________________________________________________________|             
   Pleura                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            |                                     3                                    |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  66                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 5| 7| 7| 6| 7| 7| 7| 6| 7| 7| 3| 7| 6| 7| 7| 7| 4| 7| 6| 6| 7| 7| 4|             
                             DAY ON TEST   | 2| 2| 9| 2| 2| 7| 0| 2| 2| 6| 2| 2| 3| 2| 5| 2| 2| 2| 0| 2| 0| 3| 2| 2| 2|             
                                           | 1| 6| 5| 6| 1| 7| 5| 0| 6| 4| 6| 6| 8| 7| 4| 7| 6| 7| 5| 6| 9| 7| 6| 6| 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
      Epithelium, Hyperplasia              |                                     4                                    |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  I  I|             
      Anterior Chamber, Hemorrhage         |                                                                          |             
      Anterior Chamber, Inflammation,      |                                                                          |             
          Suppurative                      |                                                                          |             
      Lens, Cataract                       |    3                 4        2                 2  1                     |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Nephropathy                          | 2  4     3  1  1  2  2  2  3  4  2     2  2  3  4  2  1  2  1  2  4  4  2|             
      Papilla, Mineralization              | 1                    1  2     1                                   1      |             
      Pelvis, Dilatation                   |                                                                      1   |             
      Pelvis, Transitional Epithelium,     |                                                                          |             
           Hyperplasia                     |                         1                                         1  2   |             
      Renal Tubule, Cyst                   |       X                                                                  |             
      Renal Tubule, Hyperplasia            |                               1                 3                    3   |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Calculus Micro Observation Only      |                         3              3                                 |             
      Transitional Epithelium, Hyperplasia |       3                                                                  |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  67                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 6| 7| 6| 7| 7| 4| 7| 7| 7| 6| 6| 7| 6| 5|            |
                             DAY ON TEST   | 2| 2| 2| 5| 2| 2| 2| 2| 2| 2| 2| 8| 2| 7| 2| 2| 7| 2| 2| 2| 0| 5| 2| 1| 5|            |
                                           | 1| 6| 7| 9| 6| 7| 7| 7| 7| 7| 6| 5| 6| 4| 7| 7| 1| 6| 7| 6| 2| 8| 6| 8| 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     |
   FISCHER 344 RATS 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                               | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Ulcer                                |                                                                         4|      1  4.0|
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  A  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Basophilic Focus                     |                X                                                         |      5     |
      Clear Cell Focus                     |                X        X  X  X                                   X      |     13     |
      Eosinophilic Focus                   |                            X  X                          X               |      6     |
      Hepatodiaphragmatic Nodule           |          4                       4        4                       4      |      6  4.0|
      Inflammation, Granulomatous          |                                                                          |      1  3.0|
      Necrosis                             |          4                                   2                           |      6  3.3|
      Vacuolization Cytoplasmic            |                                                                          |      2  2.5|
      Bile Duct, Hyperplasia               |                                                                          |      3  3.0|
      Bile Duct, Inflammation, Suppurative |                                                                          |      1  4.0|
      Centrilobular, Necrosis              |                                                                         3|      1  3.0|
      Hepatocyte, Regeneration             |             4                                                            |      2  4.0|
      Periportal, Inflammation, Chronic    |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |       +  +        +           +                                          |  12        |
      Necrosis                             |       3  3        3           3                                          |     12  3.0|
                                           |__________________________________________________________________________|____________|
   Pancreas                                | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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  68                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 6| 7| 6| 7| 7| 4| 7| 7| 7| 6| 6| 7| 6| 5|            |
                             DAY ON TEST   | 2| 2| 2| 5| 2| 2| 2| 2| 2| 2| 2| 8| 2| 7| 2| 2| 7| 2| 2| 2| 0| 5| 2| 1| 5|            |
                                           | 1| 6| 7| 9| 6| 7| 7| 7| 7| 7| 6| 5| 6| 4| 7| 7| 1| 6| 7| 6| 2| 8| 6| 8| 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     |
   FISCHER 344 RATS 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                  |                                                                          |            |
      Necrosis                             |                                                                          |      1  4.0|
      Acinus, Atrophy                      |                               2              2     2  3              3   |      7  2.4|
      Artery, Thrombosis                   |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Hyperplasia                          |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Ulcer                                |       3                                                                  |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Erosion                              |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Tongue                                  |                                                                          |   1        |
      Epithelium, Hyperplasia              |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Heart                                   | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Cardiomyopathy                       |    3        3  2                             2                    2      |      9  2.3|
      Atrium, Thrombosis                   |          4                                                               |      4  4.0|
      Valve, Inflammation, Suppurative     |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Vacuolization Cytoplasmic            |          3                                                           3   |      3  2.7|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Hyperplasia                          |       4  4                 1  4        4  4        3                 2   |     18  2.8|
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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  69                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 6| 7| 6| 7| 7| 4| 7| 7| 7| 6| 6| 7| 6| 5|            |
                             DAY ON TEST   | 2| 2| 2| 5| 2| 2| 2| 2| 2| 2| 2| 8| 2| 7| 2| 2| 7| 2| 2| 2| 0| 5| 2| 1| 5|            |
                                           | 1| 6| 7| 9| 6| 7| 7| 7| 7| 7| 6| 5| 6| 4| 7| 7| 1| 6| 7| 6| 2| 8| 6| 8| 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     |
   FISCHER 344 RATS 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|            |
 _____________________________________________________________________________________________________________________|____________|
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
      Hyperplasia                          |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Hyperplasia                          |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Cyst                                 |                               4                                          |      1  4.0|
      Hemorrhage                           |                                  4                                       |      1  4.0|
      Hyperplasia                          |                               3                             4           4|      8  3.1|
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      C-Cell, Hyperplasia                  |    1                                                                     |      3  1.7|
      Follicle, Cyst                       |                                                    2                     |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Peritoneum                              | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +        +  +  +  +  +  +  +  +|  46        |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Cyst                                 |                                                                          |      2  4.0|
      Hyperplasia                          |                   4                                                      |      2  3.5|
                                           |__________________________________________________________________________|____________|
   Prostate                                | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Inflammation, Suppurative            |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hyperplasia                          |                            3                                             |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Germinal Epithelium, Atrophy         |       4              3           4                             4         |      8  3.8|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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  70                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 6| 7| 6| 7| 7| 4| 7| 7| 7| 6| 6| 7| 6| 5|            |
                             DAY ON TEST   | 2| 2| 2| 5| 2| 2| 2| 2| 2| 2| 2| 8| 2| 7| 2| 2| 7| 2| 2| 2| 0| 5| 2| 1| 5|            |
                                           | 1| 6| 7| 9| 6| 7| 7| 7| 7| 7| 6| 5| 6| 4| 7| 7| 1| 6| 7| 6| 2| 8| 6| 8| 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     |
   FISCHER 344 RATS 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 - cont                     |                                                                          |            |
      Interstitial Cell, Hyperplasia       |                   3                                                  3   |      3  3.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hyperplasia, Reticulum Cell          |                                                                          |      1  4.0|
      Myelofibrosis                        |                               3                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |       +  +  +                          +                                 |   7        |
      Deep Cervical, Hemorrhage            |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | A  M  +  M  +  M  M  M  +  M  M  M  +  M  +  +  M  M  M  M  M  M  M  M  +|  13        |
      Ectasia                              |                                           4                              |      2  4.0|
      Hemorrhage                           |                                                                          |      1  3.0|
      Infiltration Cellular, Histiocyte    |                                     2                                    |      1  2.0|
      Pigmentation                         |                                     1                                    |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | A  M  M  M  M  M  M  M  M  M  M  M  M  +  M  M  M  M  M  M  M  M  M  M  M|   1        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  44        |
      Angiectasis                          |                3                                                         |      1  3.0|
      Pigmentation                         |                1                                                         |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Accessory Spleen                     |                                                    X                     |      1     |
      Fibrosis                             |                3                       3              3                  |      5  2.8|
      Hemorrhage                           |                                                             4            |      2  4.0|
      Necrosis                             |          4                             4                                 |      4  4.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY 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  71                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 6| 7| 6| 7| 7| 4| 7| 7| 7| 6| 6| 7| 6| 5|            |
                             DAY ON TEST   | 2| 2| 2| 5| 2| 2| 2| 2| 2| 2| 2| 8| 2| 7| 2| 2| 7| 2| 2| 2| 0| 5| 2| 1| 5|            |
                                           | 1| 6| 7| 9| 6| 7| 7| 7| 7| 7| 6| 5| 6| 4| 7| 7| 1| 6| 7| 6| 2| 8| 6| 8| 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     |
   FISCHER 344 RATS 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|            |
 _____________________________________________________________________________________________________________________|____________|
 INTEGUMENTARY SYSTEM - cont               |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Skin                                    | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Cyst Epithelial Inclusion            |                            4                                   4         |      3  4.0|
      Hyperkeratosis                       |                                                                          |      1  4.0|
      Inflammation, Acute                  |       2                                                                  |      1  2.0|
      Subcutaneous Tissue, Fibrosis        |                                                       3                  |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cranium, Maxilla, Fracture           | 4                                                                        |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         |                                                                         +|   3        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Compression                          |                                        3                       3     4   |      8  3.0|
      Hemorrhage                           | 4  3                                                                     |      3  3.7|
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        |                                                                         +|   3        |
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             |                                                                         +|   3        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Foreign Body                         |                                                                          |      3  4.0|
      Inflammation, Suppurative            |                                                                          |      2  2.5|
      Epiglottis, Metaplasia, Squamous     |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Lung                                    | 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  72                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 6| 7| 6| 7| 7| 4| 7| 7| 7| 6| 6| 7| 6| 5|            |
                             DAY ON TEST   | 2| 2| 2| 5| 2| 2| 2| 2| 2| 2| 2| 8| 2| 7| 2| 2| 7| 2| 2| 2| 0| 5| 2| 1| 5|            |
                                           | 1| 6| 7| 9| 6| 7| 7| 7| 7| 7| 6| 5| 6| 4| 7| 7| 1| 6| 7| 6| 2| 8| 6| 8| 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     |
   FISCHER 344 RATS 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                 |                                                                          |            |
      Hemorrhage                           |                                  4                                       |      5  3.2|
      Inflammation, Suppurative            |                                                                          |      2  2.5|
      Thrombosis                           |                                                                          |      1  3.0|
      Alveolar Epithelium, Hyperplasia     |                         1     1                       3                  |      7  2.0|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Histiocyte                      |                                              2           2        1      |      5  2.0|
      Alveolus, Pigmentation               |                                                                          |      1  3.0|
      Bronchiole, Alveolus, Foreign Body   |       3                                                                  |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Nose                                    | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Foreign Body                         |                            3                 3                           |      3  3.0|
      Inflammation, Suppurative            |       2              2     2                          1  2     2         |      8  1.9|
      Goblet Cell, Hyperplasia             |                                                       1                  |      1  1.0|
      Nasolacrimal Duct, Inflammation,     |                                                                          |            |
           Suppurative                     |                                           2                              |      1  2.0|
      Respiratory Epithelium, Hyperplasia  |       1                                                                  |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Pleura                                  | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Trachea                                 | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Inflammation, Suppurative            |                                                                2         |      2  2.5|
      Epithelium, Hyperplasia              |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  45        |
      Anterior Chamber, Hemorrhage         |                                     3                                    |      1  3.0|
      Anterior Chamber, Inflammation,      |                                                                          |            |
          Suppurative                      |                                                                         2|      1  2.0|
      Lens, Cataract                       |                                     4                                    |      6  2.7|
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 URINARY 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  73                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 6| 7| 6| 7| 7| 4| 7| 7| 7| 6| 6| 7| 6| 5|            |
                             DAY ON TEST   | 2| 2| 2| 5| 2| 2| 2| 2| 2| 2| 2| 8| 2| 7| 2| 2| 7| 2| 2| 2| 0| 5| 2| 1| 5|            |
                                           | 1| 6| 7| 9| 6| 7| 7| 7| 7| 7| 6| 5| 6| 4| 7| 7| 1| 6| 7| 6| 2| 8| 6| 8| 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     |
   FISCHER 344 RATS 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|            |
 _____________________________________________________________________________________________________________________|____________|
 URINARY SYSTEM - cont                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Nephropathy                          |    3  2  1  4  3  3  3  2  4  2     3  3  4  4  2  4  3  1  2  4  1  2   |     45  2.6|
      Papilla, Mineralization              |                                                                1         |      6  1.2|
      Pelvis, Dilatation                   |                                                                          |      1  1.0|
      Pelvis, Transitional Epithelium,     |                                                                          |            |
           Hyperplasia                     |             3                             2                              |      5  1.8|
      Renal Tubule, Cyst                   |                                                                          |      1     |
      Renal Tubule, Hyperplasia            |    4     2  4     3        4        3        4                 4         |     11  3.2|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Calculus Micro Observation Only      |                                                                          |      2  3.0|
      Transitional Epithelium, Hyperplasia |                                                                          |      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  74                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 5| 7| 7| 7| 7| 6| 6| 7| 7| 6| 7| 2| 7| 6| 6| 7| 6| 7| 0| 7| 7| 6|             
                             DAY ON TEST   | 2| 2| 2| 8| 2| 2| 2| 2| 9| 3| 0| 2| 1| 0| 0| 0| 7| 9| 2| 3| 2| 5| 2| 2| 3|             
                                           | 7| 7| 6| 0| 7| 7| 7| 6| 5| 7| 2| 6| 9| 2| 5| 7| 0| 5| 6| 7| 6| 7| 7| 6| 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|             
   FISCHER 344 RATS 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                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  A  +  A  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  A  +  A  +  +  +  +  +  +  +  +  +  +|             
      Diverticulum                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     |             X     X     X     X                             X     X      |             
      Clear Cell Focus                     |    X  X        X  X  X  X        X                    X     X     X      |             
      Degeneration, Cystic                 |                                                 4                        |             
      Eosinophilic Focus                   | X           X     X           X  X                 X                     |             
      Hemorrhage                           |                                                                      4   |             
      Hepatodiaphragmatic Nodule           |                      4  4     4  4                                       |             
      Mixed Cell Focus                     |                                                                          |             
      Necrosis                             |                                                                      3   |             
      Vacuolization Cytoplasmic            |                            4                                             |             
      Bile Duct, Hyperplasia               |                                                 2                        |             
      Centrilobular, Necrosis              |                                                                          |             
      Hepatocyte, Regeneration             |                                                                          |             
                                           |__________________________________________________________________________|             
   Mesentery                               |             +        +  +                             +              +   |             
      Necrosis                             |             3        3  3                             3              3   |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |          4                                                               |             
      Acinus, Atrophy                      |                      2                                                   |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  75                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 5| 7| 7| 7| 7| 6| 6| 7| 7| 6| 7| 2| 7| 6| 6| 7| 6| 7| 0| 7| 7| 6|             
                             DAY ON TEST   | 2| 2| 2| 8| 2| 2| 2| 2| 9| 3| 0| 2| 1| 0| 0| 0| 7| 9| 2| 3| 2| 5| 2| 2| 3|             
                                           | 7| 7| 6| 0| 7| 7| 7| 6| 5| 7| 2| 6| 9| 2| 5| 7| 0| 5| 6| 7| 6| 7| 7| 6| 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|             
   FISCHER 344 RATS 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                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Squamous                |                               2                                          |             
      Ulcer                                |                         2  3  4              3           3               |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Erosion                              |                                                          3               |             
      Serosa, Fibrosis                     |       2                                                                  |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       |             2  2                    3                          2         |             
      Atrium, Thrombosis                   |                                              3  2  3                     |             
      Pericardium, Fibrosis                |                                                                3         |             
      Pericardium, Inflammation, Chronic   |                                                                4         |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                         3|             
      Hyperplasia                          |                                                                          |             
      Vacuolization Cytoplasmic            |                   2                                      2               |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          | 3           1  2        2  2  1              2  1                 2      |             
      Thrombosis                           |                                                                      4   |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Hyperplasia                          |       3           3                                      3               |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  76                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 5| 7| 7| 7| 7| 6| 6| 7| 7| 6| 7| 2| 7| 6| 6| 7| 6| 7| 0| 7| 7| 6|             
                             DAY ON TEST   | 2| 2| 2| 8| 2| 2| 2| 2| 9| 3| 0| 2| 1| 0| 0| 0| 7| 9| 2| 3| 2| 5| 2| 2| 3|             
                                           | 7| 7| 6| 0| 7| 7| 7| 6| 5| 7| 2| 6| 9| 2| 5| 7| 0| 5| 6| 7| 6| 7| 7| 6| 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      C-Cell, Hyperplasia                  |                                                          1               |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |__________________________________________________________________________|             
   Peritoneum                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Penis                                   |                                                 +                        |             
                                           |__________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            |                                                                          |             
                                           |__________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Germinal Epithelium, Atrophy         | 3                       4  2                       4                 3  4|             
      Interstitial Cell, Hyperplasia       |          3                                                               |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node                              |                            +           +     +     +                 +   |             
      Infiltration Cellular, Histiocyte    |                                                                          |             
      Pancreatic, Pigmentation             |                                                                          |             
      Renal, Ectasia                       |                                        3                                 |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  M  M  M  +  M  +  M  M  +  M  M  M  +  M  M  M  M  M  +  M  M  M  +  M|             
      Ectasia                              |                                        3                                 |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | M  M  M  M  M  M  +  M  M  M  M  M  M  M  M  M  M  M  M  M  +  M  M  +  M|             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  77                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 5| 7| 7| 7| 7| 6| 6| 7| 7| 6| 7| 2| 7| 6| 6| 7| 6| 7| 0| 7| 7| 6|             
                             DAY ON TEST   | 2| 2| 2| 8| 2| 2| 2| 2| 9| 3| 0| 2| 1| 0| 0| 0| 7| 9| 2| 3| 2| 5| 2| 2| 3|             
                                           | 7| 7| 6| 0| 7| 7| 7| 6| 5| 7| 2| 6| 9| 2| 5| 7| 0| 5| 6| 7| 6| 7| 7| 6| 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                3         |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                3         |             
      Infiltration Cellular, Histiocyte    |                                                                          |             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrosis                             |                                                                          |             
      Hemorrhage                           |                                     4                                4   |             
      Necrosis                             |                            4                 4  4                        |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Galactocele                          |             3                                                            |             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperkeratosis                       |                4                                                         |             
      Hyperplasia, Focal, Squamous         |                2                                                         |             
      Inflammation, Granulomatous          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         |          +  +                          +                                 |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Compression                          |                                                             1            |             
      Hemorrhage                           |                            4              4                              |             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        |          +  +                          +                                 |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  78                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 5| 7| 7| 7| 7| 6| 6| 7| 7| 6| 7| 2| 7| 6| 6| 7| 6| 7| 0| 7| 7| 6|             
                             DAY ON TEST   | 2| 2| 2| 8| 2| 2| 2| 2| 9| 3| 0| 2| 1| 0| 0| 0| 7| 9| 2| 3| 2| 5| 2| 2| 3|             
                                           | 7| 7| 6| 0| 7| 7| 7| 6| 5| 7| 2| 6| 9| 2| 5| 7| 0| 5| 6| 7| 6| 7| 7| 6| 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 NERVOUS SYSTEM - cont                     |                                                                          |             
   Spinal Cord                             |          +  +                          +                                 |             
      Gliosis                              |                                                                          |             
      Inflammation                         |                                                                          |             
      Neuron, Degeneration                 |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         | 4                                      4                 2              4|             
      Inflammation, Suppurative            |                                                          2              1|             
      Epiglottis, Hyperplasia              |                                        2                                 |             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                           4  3                       3   |             
      Inflammation, Chronic                |                                                             1            |             
      Inflammation, Suppurative            |                                        2                                 |             
      Alveolar Epithelium, Hyperplasia     | 3                                                                        |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Histiocyte                      |                2        1                                   2     2      |             
      Interstitium, Fibrosis               |                1                                                         |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |                                                                   3  3   |             
      Inflammation, Suppurative            |                                                                   2  2   |             
      Nasolacrimal Duct, Inflammation,     |                                                                          |             
           Suppurative                     |                                                                         2|             
      Respiratory Epithelium, Hyperplasia  |                                                                   2  1   |             
                                           |__________________________________________________________________________|             
   Pleura                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                1                                            2  2  1      |             
      Mesothelium, Hyperplasia             |                                                                          |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lens, Cataract                       |                                                    3  3                  |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  79                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 5| 7| 7| 7| 7| 6| 6| 7| 7| 6| 7| 2| 7| 6| 6| 7| 6| 7| 0| 7| 7| 6|             
                             DAY ON TEST   | 2| 2| 2| 8| 2| 2| 2| 2| 9| 3| 0| 2| 1| 0| 0| 0| 7| 9| 2| 3| 2| 5| 2| 2| 3|             
                                           | 7| 7| 6| 0| 7| 7| 7| 6| 5| 7| 2| 6| 9| 2| 5| 7| 0| 5| 6| 7| 6| 7| 7| 6| 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 SPECIAL SENSES SYSTEM - cont              |                                                                          |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infarct                              |                                              X     X                     |             
      Nephropathy                          | 2  3  2  2  4  4  3  1  4     4  2  1  4  1  2  3  2  3  2  2     3  3  2|             
      Papilla, Mineralization              | 1  2  2     2  1  1        1                    1  1  2           1     1|             
      Pelvis, Transitional Epithelium,     |                                                                          |             
           Hyperplasia                     |                1              1                                          |             
      Renal Tubule, Accumulation, Hyaline  |                                                                          |             
          Droplet                          |                                                                1         |             
      Renal Tubule, Cyst                   |                                        X                                 |             
      Renal Tubule, Hyperplasia            |                2                       3                                 |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Calculus Micro Observation Only      |                                                                          |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  80                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 6| 7| 7| 5| 7| 7| 7| 7| 7| 7| 6| 7| 5| 7| 5| 7| 7| 5| 7| 7| 7| 6|            |
                             DAY ON TEST   | 6| 2| 8| 6| 2| 2| 4| 2| 2| 2| 2| 2| 2| 7| 2| 4| 2| 6| 1| 2| 3| 0| 2| 2| 9|            |
                                           | 7| 7| 8| 0| 6| 7| 4| 1| 7| 7| 6| 7| 7| 7| 6| 0| 7| 7| 3| 7| 9| 7| 6| 7| 5|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Diverticulum                         |                                           4                              |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Basophilic Focus                     |    X                    X        X  X                    X        X  X   |     13     |
      Clear Cell Focus                     |                X              X     X     X              X        X  X   |     17     |
      Degeneration, Cystic                 |                                                                          |      1  4.0|
      Eosinophilic Focus                   |          X                    X           X                    X         |     10     |
      Hemorrhage                           |                                                                          |      1  4.0|
      Hepatodiaphragmatic Nodule           |                         4     4     4                                    |      7  4.0|
      Mixed Cell Focus                     |             X                                                        X   |      2     |
      Necrosis                             |                                                                          |      1  3.0|
      Vacuolization Cytoplasmic            |                                        3                                 |      2  3.5|
      Bile Duct, Hyperplasia               |             2                                                  4        4|      4  3.0|
      Centrilobular, Necrosis              |    2                                                                     |      1  2.0|
      Hepatocyte, Regeneration             |                                                                      3   |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Mesentery                               | +           +                       +                                   +|   9        |
      Necrosis                             | 3           3                       3                                   3|      9  3.0|
                                           |__________________________________________________________________________|____________|
   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  81                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 6| 7| 7| 5| 7| 7| 7| 7| 7| 7| 6| 7| 5| 7| 5| 7| 7| 5| 7| 7| 7| 6|            |
                             DAY ON TEST   | 6| 2| 8| 6| 2| 2| 4| 2| 2| 2| 2| 2| 2| 7| 2| 4| 2| 6| 1| 2| 3| 0| 2| 2| 9|            |
                                           | 7| 7| 8| 0| 6| 7| 4| 1| 7| 7| 6| 7| 7| 7| 6| 0| 7| 7| 3| 7| 9| 7| 6| 7| 5|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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                  |                                                                          |            |
      Hemorrhage                           |                                                                          |      1  4.0|
      Acinus, Atrophy                      |                               2           2     3        2               |      5  2.2|
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Squamous                |                                                                          |      1  2.0|
      Ulcer                                |                                        4                                 |      6  3.2|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Erosion                              |                   1                                                      |      2  2.0|
      Serosa, Fibrosis                     |                                                                          |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       |             2  2     2  2        2  2     3                 2            |     12  2.2|
      Atrium, Thrombosis                   |                                                                          |      3  2.7|
      Pericardium, Fibrosis                |                                                                          |      1  3.0|
      Pericardium, Inflammation, Chronic   |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Atrophy                              |                                                                          |      1  3.0|
      Hyperplasia                          |                                                       3                  |      1  3.0|
      Vacuolization Cytoplasmic            |    2                 2                          1                    1   |      6  1.7|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          | 2        3                 2              3           3        3  4  2  3|     18  2.3|
      Thrombosis                           |                                                                          |      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  82                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 6| 7| 7| 5| 7| 7| 7| 7| 7| 7| 6| 7| 5| 7| 5| 7| 7| 5| 7| 7| 7| 6|            |
                             DAY ON TEST   | 6| 2| 8| 6| 2| 2| 4| 2| 2| 2| 2| 2| 2| 7| 2| 4| 2| 6| 1| 2| 3| 0| 2| 2| 9|            |
                                           | 7| 7| 8| 0| 6| 7| 4| 1| 7| 7| 6| 7| 7| 7| 6| 0| 7| 7| 3| 7| 9| 7| 6| 7| 5|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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                   |                                                                          |            |
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Angiectasis                          |                                        4                                 |      1  4.0|
      Hyperplasia                          |                                     4              4  4  3  3        3   |      9  3.3|
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      C-Cell, Hyperplasia                  |          2           1              3                          2         |      5  1.8|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Peritoneum                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Penis                                   |                                                                          |   1        |
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Suppurative            |          3                                                               |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Germinal Epithelium, Atrophy         |                                        4  4                              |      8  3.5|
      Interstitial Cell, Hyperplasia       |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 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  83                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 6| 7| 7| 5| 7| 7| 7| 7| 7| 7| 6| 7| 5| 7| 5| 7| 7| 5| 7| 7| 7| 6|            |
                             DAY ON TEST   | 6| 2| 8| 6| 2| 2| 4| 2| 2| 2| 2| 2| 2| 7| 2| 4| 2| 6| 1| 2| 3| 0| 2| 2| 9|            |
                                           | 7| 7| 8| 0| 6| 7| 4| 1| 7| 7| 6| 7| 7| 7| 6| 0| 7| 7| 3| 7| 9| 7| 6| 7| 5|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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               |                                                                          |            |
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              | +  +                                               +  +     +  +        +|  12        |
      Infiltration Cellular, Histiocyte    |    3                                                                     |      1  3.0|
      Pancreatic, Pigmentation             |    3                                                                     |      1  3.0|
      Renal, Ectasia                       |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | M  M  M  M  +  M  M  +  M  M  M  M  M  M  M  M  M  M  +  M  M  +  M  M  +|  12        |
      Ectasia                              |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | 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|   3        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Lymphoid                |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|  46        |
      Hyperplasia, Lymphoid                |                                                                          |      1  3.0|
      Infiltration Cellular, Histiocyte    |             4                                                            |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrosis                             |                                     2                 4              3   |      3  3.0|
      Hemorrhage                           |                                                                          |      2  4.0|
      Necrosis                             |       4                                                     4           4|      6  4.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Galactocele                          |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperkeratosis                       |                                                                          |      1  4.0|
      Hyperplasia, Focal, Squamous         |                                                                          |      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  84                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 6| 7| 7| 5| 7| 7| 7| 7| 7| 7| 6| 7| 5| 7| 5| 7| 7| 5| 7| 7| 7| 6|            |
                             DAY ON TEST   | 6| 2| 8| 6| 2| 2| 4| 2| 2| 2| 2| 2| 2| 7| 2| 4| 2| 6| 1| 2| 3| 0| 2| 2| 9|            |
                                           | 7| 7| 8| 0| 6| 7| 4| 1| 7| 7| 6| 7| 7| 7| 6| 0| 7| 7| 3| 7| 9| 7| 6| 7| 5|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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|            |
 _____________________________________________________________________________________________________________________|____________|
 INTEGUMENTARY SYSTEM - cont               |                                                                          |            |
      Inflammation, Granulomatous          |       3                                                                  |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         |          +                                                               |   4        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Compression                          |          3  3                                                            |      3  2.3|
      Hemorrhage                           |                   4        1                 2                          4|      6  3.2|
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        |          +                                                               |   4        |
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             |          +                                   +                           |   5        |
      Gliosis                              |                                              2                           |      1  2.0|
      Inflammation                         |                                              3                           |      1  3.0|
      Neuron, Degeneration                 |                                              2                           |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Foreign Body                         |                         4                                   4            |      6  3.7|
      Inflammation, Suppurative            |                                                                          |      2  1.5|
      Epiglottis, Hyperplasia              |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemorrhage                           |                   1     2                                                |      5  2.6|
      Inflammation, Chronic                |                                                                      2   |      2  1.5|
      Inflammation, Suppurative            |                                                                          |      1  2.0|
      Alveolar Epithelium, Hyperplasia     |    1                 1                                   2               |      4  1.8|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 6| 7| 7| 5| 7| 7| 7| 7| 7| 7| 6| 7| 5| 7| 5| 7| 7| 5| 7| 7| 7| 6|            |
                             DAY ON TEST   | 6| 2| 8| 6| 2| 2| 4| 2| 2| 2| 2| 2| 2| 7| 2| 4| 2| 6| 1| 2| 3| 0| 2| 2| 9|            |
                                           | 7| 7| 8| 0| 6| 7| 4| 1| 7| 7| 6| 7| 7| 7| 6| 0| 7| 7| 3| 7| 9| 7| 6| 7| 5|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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                 |                                                                          |            |
           Histiocyte                      |    2                                                                 2   |      6  1.8|
      Interstitium, Fibrosis               |                                           1                 3            |      3  1.7|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Foreign Body                         |             3                                3                           |      4  3.0|
      Inflammation, Suppurative            |             1                                                  2         |      4  1.8|
      Nasolacrimal Duct, Inflammation,     |                                                                          |            |
           Suppurative                     |                                                                          |      1  2.0|
      Respiratory Epithelium, Hyperplasia  |                                              3                           |      3  2.0|
                                           |__________________________________________________________________________|____________|
   Pleura                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic                |                                                 1                    2   |      6  1.5|
      Mesothelium, Hyperplasia             |                                                                2         |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  I  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +|  46        |
      Lens, Cataract                       |                2                                                         |      3  2.7|
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Infarct                              | X                 X                                                      |      4     |
      Nephropathy                          | 2  1  1  3  4  2  1  2  2  2  2  2  3  4  2  2  4  2  2  3     2  2  4  2|     47  2.4|
      Papilla, Mineralization              | 1     1  1        3  3              2  1        2     3  2               |     22  1.6|
      Pelvis, Transitional Epithelium,     |                                                                          |            |
           Hyperplasia                     |                      1              1           1                    2   |      6  1.2|
      Renal Tubule, Accumulation, Hyaline  |                                                                          |            |
          Droplet                          |                                                             2            |      2  1.5|
      Renal Tubule, Cyst                   |                                                                          |      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  86                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 6| 7| 7| 5| 7| 7| 7| 7| 7| 7| 6| 7| 5| 7| 5| 7| 7| 5| 7| 7| 7| 6|            |
                             DAY ON TEST   | 6| 2| 8| 6| 2| 2| 4| 2| 2| 2| 2| 2| 2| 7| 2| 4| 2| 6| 1| 2| 3| 0| 2| 2| 9|            |
                                           | 7| 7| 8| 0| 6| 7| 4| 1| 7| 7| 6| 7| 7| 7| 6| 0| 7| 7| 3| 7| 9| 7| 6| 7| 5|            |
 __________________________________________|__________________________________________________________________________|      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     |
   FISCHER 344 RATS 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                     |                                                                          |            |
      Renal Tubule, Hyperplasia            |                1                                                         |      3  2.0|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Calculus Micro Observation Only      |          2                                                  2            |      2  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  87                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 4| 7| 6| 7| 6| 6| 6| 7| 7| 6| 6| 7| 7| 6| 7| 5| 7| 7| 6| 6| 6| 6| 7|             
                             DAY ON TEST   | 4| 2| 9| 2| 7| 2| 5| 3| 3| 2| 0| 0| 6| 2| 2| 8| 0| 9| 2| 1| 3| 2| 7| 3| 2|             
                                           | 5| 7| 8| 7| 4| 6| 9| 8| 8| 6| 2| 9| 5| 6| 6| 1| 5| 5| 6| 2| 9| 2| 7| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Ulcer                                |             4        4                                                   |             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                               3                                          |             
      Basophilic Focus                     |                   X                    X                                 |             
      Clear Cell Focus                     |          X                 X           X              X                  |             
      Degeneration, Cystic                 |                                                          3               |             
      Eosinophilic Focus                   |    X                                   X        X     X                  |             
      Hepatodiaphragmatic Nodule           |          4        4                    4  4     4                        |             
      Mixed Cell Focus                     |                                           X                              |             
      Bile Duct, Hyperplasia               |                                  2  3                    3               |             
      Centrilobular, Necrosis              | 1     3              2                          1                        |             
      Hepatocyte, Regeneration             |             4                             4                              |             
                                           |__________________________________________________________________________|             
   Mesentery                               |       +                             +                                +   |             
      Necrosis                             |       3                             3                                4   |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Acinus, Atrophy                      |                                                          2               |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Squamous                |       4                                                                  |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  88                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 4| 7| 6| 7| 6| 6| 6| 7| 7| 6| 6| 7| 7| 6| 7| 5| 7| 7| 6| 6| 6| 6| 7|             
                             DAY ON TEST   | 4| 2| 9| 2| 7| 2| 5| 3| 3| 2| 0| 0| 6| 2| 2| 8| 0| 9| 2| 1| 3| 2| 7| 3| 2|             
                                           | 5| 7| 8| 7| 4| 6| 9| 8| 8| 6| 2| 9| 5| 6| 6| 1| 5| 5| 6| 2| 9| 2| 7| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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                  |                                                                          |             
      Ulcer                                |       4                       3                             4            |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Erosion                              |                      2                                                   |             
      Ulcer                                |                                  4                                       |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       |                            2                          2                  |             
      Atrium, Thrombosis                   |                      4                                                   |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Necrosis                             |                                                                          |             
      Vacuolization Cytoplasmic            |             2                                            2               |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          | 4  3  3  2  3     2  3     4        4                 2  2        4     3|             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                      4                                                   |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                                          |             
      Hemorrhage                           |                                                                          |             
      Hyperplasia                          |                      3                       4                          4|             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      C-Cell, Hyperplasia                  |                                                                         2|             
      Follicle, Cyst                       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  89                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 4| 7| 6| 7| 6| 6| 6| 7| 7| 6| 6| 7| 7| 6| 7| 5| 7| 7| 6| 6| 6| 6| 7|             
                             DAY ON TEST   | 4| 2| 9| 2| 7| 2| 5| 3| 3| 2| 0| 0| 6| 2| 2| 8| 0| 9| 2| 1| 3| 2| 7| 3| 2|             
                                           | 5| 7| 8| 7| 4| 6| 9| 8| 8| 6| 2| 9| 5| 6| 6| 1| 5| 5| 6| 2| 9| 2| 7| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 GENERAL BODY SYSTEM - cont                |                                                                          |             
                                           |__________________________________________________________________________|             
   Peritoneum                              | +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                   4                                                      |             
      Inflammation, Granulomatous          |                                                                          |             
                                           |__________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            |                                                 2                        |             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Germinal Epithelium, Atrophy         | 3                 4                    4        4        4  4     4  3   |             
      Interstitial Cell, Hyperplasia       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node                              |          +  +  +        +                                   +  +     +   |             
      Deep Cervical, Pigmentation          |          2                                                               |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | M  M  M  M  M  +  M  M  M  M  M  M  M  M  +  M  M  +  M  M  +  M  M  M  M|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | 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|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  M  +  +  +  +  M|             
      Hyperplasia, Lymphoid                |                                                       4                  |             
      Pigmentation                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  90                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 4| 7| 6| 7| 6| 6| 6| 7| 7| 6| 6| 7| 7| 6| 7| 5| 7| 7| 6| 6| 6| 6| 7|             
                             DAY ON TEST   | 4| 2| 9| 2| 7| 2| 5| 3| 3| 2| 0| 0| 6| 2| 2| 8| 0| 9| 2| 1| 3| 2| 7| 3| 2|             
                                           | 5| 7| 8| 7| 4| 6| 9| 8| 8| 6| 2| 9| 5| 6| 6| 1| 5| 5| 6| 2| 9| 2| 7| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
      Accessory Spleen                     |                                                    X                     |             
      Fibrosis                             |                               4  4                                4      |             
      Hemorrhage                           |                                                                          |             
      Necrosis                             |             4                       4                                    |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Galactocele                          |                                  4                                       |             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst Epithelial Inclusion            |                                                 4                        |             
      Hyperkeratosis                       |                                                       3                  |             
      Inflammation, Granulomatous          |                                                       3                  |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Tibia, Fracture                      | X                                                                        |             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         |                      +                                                   |             
      Hemorrhage                           |                      2                                                   |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Compression                          |       4           4              2                                       |             
      Hemorrhage                           |             4           4           2                                    |             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Spinal Cord                             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  91                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 4| 7| 6| 7| 6| 6| 6| 7| 7| 6| 6| 7| 7| 6| 7| 5| 7| 7| 6| 6| 6| 6| 7|             
                             DAY ON TEST   | 4| 2| 9| 2| 7| 2| 5| 3| 3| 2| 0| 0| 6| 2| 2| 8| 0| 9| 2| 1| 3| 2| 7| 3| 2|             
                                           | 5| 7| 8| 7| 4| 6| 9| 8| 8| 6| 2| 9| 5| 6| 6| 1| 5| 5| 6| 2| 9| 2| 7| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
      Foreign Body                         |                                        4                             4   |             
      Inflammation, Suppurative            |                                  2                                   1   |             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar Epithelium, Hyperplasia     |                                        2                       1         |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Histiocyte                      |                   1                    2                    3  3         |             
      Bronchiole, Hyperplasia              |                                                                          |             
      Interstitium, Fibrosis               |                                                                1         |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Foreign Body                         |                            3                                   3         |             
      Inflammation, Suppurative            |             1              1                                   1     2   |             
      Goblet Cell, Hyperplasia             |             2              2                                             |             
      Nasolacrimal Duct, Inflammation,     |                                                                          |             
           Suppurative                     |       2                                                                  |             
      Respiratory Epithelium, Hyperplasia  |                                                                          |             
                                           |__________________________________________________________________________|             
   Pleura                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                   2                                                      |             
      Mesothelium, Hyperplasia             |                                                                          |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  I|             
      Cornea, Hyperplasia                  |                                                                          |             
      Lens, Cataract                       |          3                                                               |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Zymbal's Gland                          |                                                    +                     |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infarct                              |             X                 X                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  92                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 4| 7| 6| 7| 6| 6| 6| 7| 7| 6| 6| 7| 7| 6| 7| 5| 7| 7| 6| 6| 6| 6| 7|             
                             DAY ON TEST   | 4| 2| 9| 2| 7| 2| 5| 3| 3| 2| 0| 0| 6| 2| 2| 8| 0| 9| 2| 1| 3| 2| 7| 3| 2|             
                                           | 5| 7| 8| 7| 4| 6| 9| 8| 8| 6| 2| 9| 5| 6| 6| 1| 5| 5| 6| 2| 9| 2| 7| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 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|             
   FISCHER 344 RATS 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 - cont                     |                                                                          |             
      Nephropathy                          | 4  3  4  3  2  2  4  4  3  4  3  4  2  3  3  2  3  2  4  4  4  3  4  3  3|             
      Papilla, Mineralization              | 1  1     1     2     2           1        2  2  1  1  2  1     1     1  2|             
      Pelvis, Transitional Epithelium,     |                                                                          |             
           Hyperplasia                     | 1  1     1     1           1     1        3     2     1  2               |             
      Renal Tubule, Accumulation, Hyaline  |                                                                          |             
          Droplet                          |                                                                          |             
      Renal Tubule, Hyperplasia            |    4                 2           1        4  4        2  1              3|             
      Renal Tubule, Pigmentation           |                                                                          |             
      Transitional Epithelium, Hyperplasia |                                                                         3|             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  93                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 5| 5| 7| 7| 6| 6| 6| 7| 7| 7| 7| 6| 7| 7| 7| 6| 6| 7| 7| 6| 6| 7| 6| 7| 6|            |
                             DAY ON TEST   | 4| 6| 2| 2| 2| 2| 4| 2| 2| 2| 2| 0| 2| 2| 0| 5| 4| 1| 2| 9| 9| 2| 9| 2| 5|            |
                                           | 4| 7| 6| 6| 1| 3| 5| 7| 6| 6| 7| 4| 6| 6| 6| 3| 9| 9| 6| 4| 3| 6| 4| 6| 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     |
   FISCHER 344 RATS 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        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Ulcer                                |                                                                          |      2  4.0|
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Angiectasis                          |                                                                          |      1  3.0|
      Basophilic Focus                     |       X                 X                                                |      4     |
      Clear Cell Focus                     |       X                    X           X              X              X   |      9     |
      Degeneration, Cystic                 |                                     3        3                           |      3  3.0|
      Eosinophilic Focus                   |                         X  X        X                 X              X   |      9     |
      Hepatodiaphragmatic Nodule           |                         4                                4               |      7  4.0|
      Mixed Cell Focus                     |                                                                          |      1     |
      Bile Duct, Hyperplasia               |          4                                                               |      4  3.0|
      Centrilobular, Necrosis              |                                                                          |      4  1.8|
      Hepatocyte, Regeneration             |             4                                                           3|      4  3.8|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |             +              +           +     +                           |   7        |
      Necrosis                             |             3              3           3     2                           |      7  3.0|
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Acinus, Atrophy                      |                      3                                                   |      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  94                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 5| 5| 7| 7| 6| 6| 6| 7| 7| 7| 7| 6| 7| 7| 7| 6| 6| 7| 7| 6| 6| 7| 6| 7| 6|            |
                             DAY ON TEST   | 4| 6| 2| 2| 2| 2| 4| 2| 2| 2| 2| 0| 2| 2| 0| 5| 4| 1| 2| 9| 9| 2| 9| 2| 5|            |
                                           | 4| 7| 6| 6| 1| 3| 5| 7| 6| 6| 7| 4| 6| 6| 6| 3| 9| 9| 6| 4| 3| 6| 4| 6| 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     |
   FISCHER 344 RATS 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                  |                                                                          |            |
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia, Squamous                |                                                                          |      1  4.0|
      Ulcer                                | 4                                            4           4               |      6  3.8|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Erosion                              |                                                 1                       3|      3  2.0|
      Ulcer                                |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cardiomyopathy                       |       2                    2           2  2           2        2         |      8  2.0|
      Atrium, Thrombosis                   |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Necrosis                             |                                           2                              |      1  2.0|
      Vacuolization Cytoplasmic            |                2                                                         |      3  2.0|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          | 1     2  2     1                       4  2  3     4     3  4  2         |     24  2.8|
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst                                 |             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  95                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 5| 5| 7| 7| 6| 6| 6| 7| 7| 7| 7| 6| 7| 7| 7| 6| 6| 7| 7| 6| 6| 7| 6| 7| 6|            |
                             DAY ON TEST   | 4| 6| 2| 2| 2| 2| 4| 2| 2| 2| 2| 0| 2| 2| 0| 5| 4| 1| 2| 9| 9| 2| 9| 2| 5|            |
                                           | 4| 7| 6| 6| 1| 3| 5| 7| 6| 6| 7| 4| 6| 6| 6| 3| 9| 9| 6| 4| 3| 6| 4| 6| 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     |
   FISCHER 344 RATS 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|            |
 _____________________________________________________________________________________________________________________|____________|
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
      Hemorrhage                           |                                     3                                    |      1  3.0|
      Hyperplasia                          |                4  3        4  4                    4           4         |      9  3.8|
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      C-Cell, Hyperplasia                  |                                                                          |      1  2.0|
      Follicle, Cyst                       |                                                                   4      |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Peritoneum                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hyperplasia                          |       4     3                                                            |      3  3.7|
      Inflammation, Granulomatous          |                                        2                                 |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Suppurative            |                                                          3               |      2  2.5|
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Germinal Epithelium, Atrophy         |    4           4  4     3  4        4                       3            |     15  3.7|
      Interstitial Cell, Hyperplasia       | 3                                            3                          3|      3  3.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |    +     +  +                 +           +     +  +                    +|  15        |
      Deep Cervical, Pigmentation          |                                                                          |      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  96                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 5| 5| 7| 7| 6| 6| 6| 7| 7| 7| 7| 6| 7| 7| 7| 6| 6| 7| 7| 6| 6| 7| 6| 7| 6|            |
                             DAY ON TEST   | 4| 6| 2| 2| 2| 2| 4| 2| 2| 2| 2| 0| 2| 2| 0| 5| 4| 1| 2| 9| 9| 2| 9| 2| 5|            |
                                           | 4| 7| 6| 6| 1| 3| 5| 7| 6| 6| 7| 4| 6| 6| 6| 3| 9| 9| 6| 4| 3| 6| 4| 6| 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     |
   FISCHER 344 RATS 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               |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | M  +  M  M  M  M  M  M  M  M  M  M  M  M  M  M  +  M  M  M  +  M  M  M  M|   7        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  +  M  M|   2        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  +  +  +  +  M  +  M  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|  44        |
      Hyperplasia, Lymphoid                |                                                                          |      1  4.0|
      Pigmentation                         |                4                                                         |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Accessory Spleen                     |                                                                          |      1     |
      Fibrosis                             |                            3           4           3  4           3      |      8  3.6|
      Hemorrhage                           |                                                                         4|      1  4.0|
      Necrosis                             |                                           4     4                        |      4  4.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Galactocele                          |                         4                    4                           |      3  4.0|
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cyst Epithelial Inclusion            |       4  4                          4                                    |      4  4.0|
      Hyperkeratosis                       |                                                    1     3               |      3  2.3|
      Inflammation, Granulomatous          |                                        2                                 |      2  2.5|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Tibia, Fracture                      |                                                                          |      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  97                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 5| 5| 7| 7| 6| 6| 6| 7| 7| 7| 7| 6| 7| 7| 7| 6| 6| 7| 7| 6| 6| 7| 6| 7| 6|            |
                             DAY ON TEST   | 4| 6| 2| 2| 2| 2| 4| 2| 2| 2| 2| 0| 2| 2| 0| 5| 4| 1| 2| 9| 9| 2| 9| 2| 5|            |
                                           | 4| 7| 6| 6| 1| 3| 5| 7| 6| 6| 7| 4| 6| 6| 6| 3| 9| 9| 6| 4| 3| 6| 4| 6| 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     |
   FISCHER 344 RATS 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|            |
 _____________________________________________________________________________________________________________________|____________|
 MUSCULOSKELETAL SYSTEM - cont             |                                                                          |            |
   Skeletal Muscle                         |          +                    +     +                 +     +            |   6        |
      Hemorrhage                           |                                                                          |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Compression                          |                         3                    1                    3      |      6  2.8|
      Hemorrhage                           |                                                          4               |      4  3.5|
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        |          +                    +     +                 +     +            |   5        |
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             |          +                    +     +                 +     +            |   5        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Foreign Body                         |                         4                                4               |      4  4.0|
      Inflammation, Suppurative            |                                                                          |      2  1.5|
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar Epithelium, Hyperplasia     |                                     3                             2      |      4  2.0|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Histiocyte                      |                                                          2     1         |      6  2.0|
      Bronchiole, Hyperplasia              |                                     3                                    |      1  3.0|
      Interstitium, Fibrosis               |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Foreign Body                         |                   3  3        3                                3     3   |      7  3.0|
      Inflammation, Suppurative            |       1           2  1           2                             1     1   |     10  1.3|
      Goblet Cell, Hyperplasia             |                   3           3                                      2   |      5  2.4|
      Nasolacrimal Duct, Inflammation,     |                                                                          |            |
           Suppurative                     |                                                                          |      1  2.0|
      Respiratory Epithelium, Hyperplasia  |                   3              2                             1         |      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  98                                                               
                                                                                                                                   
NTP Experiment-Test: 97006-01                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: CHRONIC                                       METHYL ISOBUTYL KETONE                                  Date: 05/11/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 09:01:52    
 __________________________________________________________________________________________________________________________________ 
                                           | 5| 5| 7| 7| 6| 6| 6| 7| 7| 7| 7| 6| 7| 7| 7| 6| 6| 7| 7| 6| 6| 7| 6| 7| 6|            |
                             DAY ON TEST   | 4| 6| 2| 2| 2| 2| 4| 2| 2| 2| 2| 0| 2| 2| 0| 5| 4| 1| 2| 9| 9| 2| 9| 2| 5|            |
                                           | 4| 7| 6| 6| 1| 3| 5| 7| 6| 6| 7| 4| 6| 6| 6| 3| 9| 9| 6| 4| 3| 6| 4| 6| 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     |
   FISCHER 344 RATS 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                 |                                                                          |            |
   Pleura                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Inflammation, Chronic                |                                                          2     1        1|      4  1.5|
      Mesothelium, Hyperplasia             |                            4                                             |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Cornea, Hyperplasia                  | 2                                                                        |      1  2.0|
      Lens, Cataract                       |                                                    3                     |      2  3.0|
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Zymbal's Gland                          |                                                                      +   |   2        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Infarct                              |                   X                                                      |      3     |
      Nephropathy                          | 1  1  4  3  2  2  2  2  4  3  2  3  3  3  4  4  2  4  4  4  3  4  4  4  3|     50  3.1|
      Papilla, Mineralization              | 1  1     1     3     2     2  1     3        1  2  2              1  2  1|     29  1.5|
      Pelvis, Transitional Epithelium,     |                                                                          |            |
           Hyperplasia                     |       3                 2  1  1     1  1  1  2     1                     |     19  1.4|
      Renal Tubule, Accumulation, Hyaline  |                                                                          |            |
          Droplet                          | 1  1                                                                     |      2  1.0|
      Renal Tubule, Hyperplasia            |       2  3              3              3  4        2  2  2  2           4|     18  2.7|
      Renal Tubule, Pigmentation           |                3                                                         |      1  3.0|
      Transitional Epithelium, Hyperplasia |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   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  99                                                               
                                                                                                                                   
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                             ----------              END OF REPORT             ----------                                           
                             ------------------------------------------------------------                                           
NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.