Skip to Main Navigation
Skip to Page Content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it's official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Share This:
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                                                               
                                                                                                                                   
                             ------------------------------------------------------------                                           
                             ----------              END OF REPORT             ----------                                           
                             ------------------------------------------------------------