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TDMS Study 05135-06 Pathology Tables

NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26




       Facility:  Battelle Northwest

       Chemical CAS #:  78-79-5

       Lock Date:  None

       Cage Range:  All

       Reasons For Removal:    All

       Removal Date Range:     All

       Treatment Groups:       Include All






































                                                              Page   1


NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 0| 3| 3| 3| 3| 3| 3| 1| 1| 1| 3| 1| 1|             
                             DAY ON TEST   | 7| 8| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 9| 7| 7| 7| 7| 7| 7| 8| 8| 8| 7| 8| 8|             
                                           | 3| 9| 3| 3| 3| 3| 3| 3| 1| 1| 3| 1| 0| 3| 3| 3| 3| 3| 3| 5| 3| 3| 3| 3| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     |       4                                X           X                     |             
      Deformity                            |                                                                          |             
      Eosinophilic Focus                   |                                                    X                     |             
      Vacuolization Cytoplasmic            | 1        2     2  1  2  1  2  2  2     2  2  3  2  1  1                  |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                                                             +            |             
      Necrosis                             |                                                             2            |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Focal Cellular Change                |                                              1                           |             
                                           |__________________________________________________________________________|             
   Pharynx                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            |                            2     2                                       |             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Epithelium, Hyperplasia              |          2                                                               |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page   2                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 0| 3| 3| 3| 3| 3| 3| 1| 1| 1| 3| 1| 1|             
                             DAY ON TEST   | 7| 8| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 9| 7| 7| 7| 7| 7| 7| 8| 8| 8| 7| 8| 8|             
                                           | 3| 9| 3| 3| 3| 3| 3| 3| 1| 1| 3| 1| 0| 3| 3| 3| 3| 3| 3| 5| 3| 3| 3| 3| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE 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                  |                                                                          |             
      Ulcer                                |          1                                                               |             
                                           |__________________________________________________________________________|             
   Tongue                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Tooth                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pericardium, Hemorrhage              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                                                          |             
      Hyperplasia                          |          1           1  1  1                                      1      |             
      Hypertrophy, Focal                   |                                           1        1              1      |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |          1              1     1        1     2  1  2                     |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  M  +  +  M  +  +  M  +  +  +  M  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Cyst                  |    X  X                                                                  |             
      Pars Intermedia, Hyperplasia         |    4                                                                     |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                                   X      |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page   3                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 0| 3| 3| 3| 3| 3| 3| 1| 1| 1| 3| 1| 1|             
                             DAY ON TEST   | 7| 8| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 9| 7| 7| 7| 7| 7| 7| 8| 8| 8| 7| 8| 8|             
                                           | 3| 9| 3| 3| 3| 3| 3| 3| 1| 1| 3| 1| 0| 3| 3| 3| 3| 3| 3| 5| 3| 3| 3| 3| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Penis                                   |    +                                                                     |             
                                           |__________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            |                                                                          |             
                                           |__________________________________________________________________________|             
   Prostate                                | +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |    3                                                                     |             
                                           |__________________________________________________________________________|             
   Lymph Node                              |    +                                                                     |             
      Iliac, Hyperplasia                   |    2                                                                     |             
      Inguinal, Hyperplasia                |    2                                                                     |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  +  +  +  M  M  +  +  +  +  +  +  +  +  M  M  M  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | M  M  +  +  +  M  M  +  M  M  +  +  +  +  M  +  +  M  +  +  M  +  +  M  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | M  +  +  M  M  M  M  +  +  +  M  M  +  M  M  +  +  +  M  +  +  M  M  M  +|             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     |    2        2                                                            |             
      Pigmentation, Melanin                |                                              2                           |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page   4                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 0| 3| 3| 3| 3| 3| 3| 1| 1| 1| 3| 1| 1|             
                             DAY ON TEST   | 7| 8| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 9| 7| 7| 7| 7| 7| 7| 8| 8| 8| 7| 8| 8|             
                                           | 3| 9| 3| 3| 3| 3| 3| 3| 1| 1| 3| 1| 0| 3| 3| 3| 3| 3| 3| 5| 3| 3| 3| 3| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Prepuce, Inflammation, Chronic       |    4        4                                                            |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Mineralization                       |                                              1                           |             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Spinal Cord                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration                         |          1                       1                                       |             
      Meninges, Hemorrhage                 |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                            2     2                                       |             
      Hemorrhage                           |                                                                          |             
      Metaplasia, Osseous                  |                                                                      1   |             
      Alveolar Epithelium, Hyperplasia     |                                                                          |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Turbinate, Olfactory Epithelium,     |                                                                          |             
           Degeneration                    |                                     1                                    |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page   5                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 0| 3| 3| 3| 3| 3| 3| 1| 1| 1| 3| 1| 1|             
                             DAY ON TEST   | 7| 8| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 9| 7| 7| 7| 7| 7| 7| 8| 8| 8| 7| 8| 8|             
                                           | 3| 9| 3| 3| 3| 3| 3| 3| 1| 1| 3| 1| 0| 3| 3| 3| 3| 3| 3| 5| 3| 3| 3| 3| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE 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|             
 __________________________________________|__________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                        2                                 |             
                                           |__________________________________________________________________________|             
   Zymbal's Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Bilateral, Fibrosis                  |                                                                      1   |             
      Bilateral, Hydronephrosis            |                                                                          |             
      Bilateral, Metaplasia, Osseous       |                                                                          |             
      Bilateral, Pelvis, Inflammation,     |                                                                          |             
           Suppurative                     |                                                                          |             
      Bilateral, Renal Tubule, Hyperplasia | 1                                                                        |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Calculus Micro Observation Only      |                                                                          |             
      Dilatation                           |    2                                                                     |             
      Inflammation, Suppurative            |             1                                                            |             
      Transitional Epithelium, Hyperplasia |                                                                          |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   6                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 7| 8| 7| 7| 7| 8| 8| 8| 8|                             |            |
                                           | 3| 3| 3| 1| 3| 3| 1| 2| 3| 3| 3| 5| 5| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 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|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Basophilic Focus                     |                                                                          |      3  4.0|
      Deformity                            |                               X                                          |      1     |
      Eosinophilic Focus                   |                                                                          |      1     |
      Vacuolization Cytoplasmic            | 1     2     2  2  2           2  1                                       |     22  1.7|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   1        |
      Necrosis                             |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Focal Cellular Change                |                1                                                         |      2  1.0|
                                           |__________________________________________________________________________|____________|
   Pharynx                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Inflammation, Suppurative            |                                                                          |      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   7                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 7| 8| 7| 7| 7| 8| 8| 8| 8|                             |            |
                                           | 3| 3| 3| 1| 3| 3| 1| 2| 3| 3| 3| 5| 5| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 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|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Epithelium, Hyperplasia              |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Ulcer                                |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Tongue                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Tooth                                   |          +                                                               |   1        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Pericardium, Hemorrhage              |                      4                                                   |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hemorrhage                           |                      4                                                   |      1  4.0|
      Hyperplasia                          |                   1                                                      |      6  1.0|
      Hypertrophy, Focal                   |    1     1                                                               |      5  1.0|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hyperplasia                          |       1                       2                                          |      9  1.3|
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  M  +  +  M  +  +  +  +  +  +  +  +  +  +                              |  34        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  M  M  +  +  +  +                              |  38        |
      Pars Distalis, Cyst                  |                                                                          |      2     |
      Pars Intermedia, Hyperplasia         |                                                                          |      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   8                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 7| 8| 7| 7| 7| 8| 8| 8| 8|                             |            |
                                           | 3| 3| 3| 1| 3| 3| 1| 2| 3| 3| 3| 5| 5| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 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|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Cyst                                 |                                                                          |      1     |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Penis                                   |                                                                          |   1        |
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Inflammation, Suppurative            |                1                                                         |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +                              |  38        |
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hyperplasia                          |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |                                                                          |   1        |
      Iliac, Hyperplasia                   |                                                                          |      1  2.0|
      Inguinal, Hyperplasia                |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | M  +  +  M  +  +  M  +  +  +  +  +  +  +  +                              |  32        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  M  +  +  +  M  M  +  M  M  M  +  +                              |  24        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 7| 8| 7| 7| 7| 8| 8| 8| 8|                             |            |
                                           | 3| 3| 3| 1| 3| 3| 1| 2| 3| 3| 3| 5| 5| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 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|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  M  M  M  +  M  M  +  +  M  +  +  M  +  M                              |  19        |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hematopoietic Cell Proliferation     |                                                                          |      2  2.0|
      Pigmentation, Melanin                |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M                              |            |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Prepuce, Inflammation, Chronic       |                                                                          |      2  4.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Mineralization                       |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Degeneration                         |       1                       1                                          |      4  1.0|
      Meninges, Hemorrhage                 |                      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  10                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 7| 8| 7| 7| 7| 8| 8| 8| 8|                             |            |
                                           | 3| 3| 3| 1| 3| 3| 1| 2| 3| 3| 3| 5| 5| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 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|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Congestion                           |                   1                                                      |      3  1.7|
      Hemorrhage                           | 2        1           2                                                   |      3  1.7|
      Metaplasia, Osseous                  |                                                                          |      1  1.0|
      Alveolar Epithelium, Hyperplasia     | 4                                                                        |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Turbinate, Olfactory Epithelium,     |                                                                          |            |
           Degeneration                    |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hyperplasia                          |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Zymbal's Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Bilateral, Fibrosis                  |             2                                                            |      2  1.5|
      Bilateral, Hydronephrosis            |                         2           2                                    |      2  2.0|
      Bilateral, Metaplasia, Osseous       |       1                                                                  |      1  1.0|
      Bilateral, Pelvis, Inflammation,     |                                                                          |            |
           Suppurative                     |                         2                                                |      1  2.0|
      Bilateral, Renal Tubule, Hyperplasia |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  11                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 7| 8| 7| 7| 7| 8| 8| 8| 8|                             |            |
                                           | 3| 3| 3| 1| 3| 3| 1| 2| 3| 3| 3| 5| 5| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 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|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 URINARY SYSTEM - cont                     |                                                                          |            |
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Calculus Micro Observation Only      |                         X                                                |      1     |
      Dilatation                           |                                                                          |      1  2.0|
      Inflammation, Suppurative            |                         2                                                |      2  1.5|
      Transitional Epithelium, Hyperplasia |                         3                                                |      1  3.0|
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  12                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 0| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
                             DAY ON TEST   | 7| 1| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                                           | 3| 6| 9| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE 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|             
    70 PPM                                 | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Gallbladder                             |    +  A                                                                  |             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                |    +  A                                                                  |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  |    +  A                                                                  |             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     |                                                                X         |             
      Infarct                              |                                              4                           |             
      Vacuolization Cytoplasmic            | 1           1     1  1  1  1  1  2     2  1  1  1  1     1     1  1  1  1|             
                                           |__________________________________________________________________________|             
   Mesentery                               |                +                                            +            |             
      Necrosis                             |                2                                            2            |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Focal Cellular Change                |                                                                          |             
      Inflammation, Chronic                |                   1                                               1      |             
      Duct, Cyst                           |                                                                      X   |             
                                           |__________________________________________________________________________|             
   Pharynx                                 |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Epithelium, Hyperplasia              |                   2                                                      |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  13                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 0| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
                             DAY ON TEST   | 7| 1| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                                           | 3| 6| 9| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE 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|             
    70 PPM                                 | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|             
                                           | 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                          |                                                                2         |             
      Inflammation, Suppurative            |                                                                          |             
      Pigmentation, Hemosiderin            |       1                                                                  |             
                                           |__________________________________________________________________________|             
   Tongue                                  |    +  +                                                                  |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Heart                                   |    +  +                                                                  |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |             3     1  1     1     1     1  1     1                        |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           |    +  +                                                                  |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              |    +  +                                                                  |             
      Inflammation                         |       2                                                                  |             
                                           |__________________________________________________________________________|             
   Preputial Gland                         |    +  +                                                                  |             
      Hemorrhage                           |    3                                                                     |             
      Inflammation, Suppurative            |    2  1                                                                  |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  14                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 0| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
                             DAY ON TEST   | 7| 1| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                                           | 3| 6| 9| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE 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|             
    70 PPM                                 | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|             
                                           | 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                     |                                                                          |             
      Necrosis                             |    2                                                                     |             
                                           |__________________________________________________________________________|             
   Prostate                                |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Lymph Node                              |                +                                                         |             
      Iliac, Hyperplasia                   |                2                                                         |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   |    +  M                                                                  |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  |    M  +                                                                  |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  |    +  +                                   +                              |             
      Hyperplasia                          |                                           2                              |             
      Necrosis                             |    2                                                                     |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +        +                             +                           |             
      Accessory Spleen                     | X                                                                        |             
      Hematopoietic Cell Proliferation     |                2                                                         |             
      Necrosis                             |    2                                                                     |             
      Pigmentation, Melanin                | 2                                            2                           |             
                                           |__________________________________________________________________________|             
   Thymus                                  |    +  +                                                                  |             
      Necrosis                             |    3  3                                                                  |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           |    M  M                                                                  |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  15                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 0| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
                             DAY ON TEST   | 7| 1| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                                           | 3| 6| 9| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE 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|             
    70 PPM                                 | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
   Skin                                    |    +  +        +                                                  +      |             
      Hemorrhage                           |    2                                                                     |             
      Inflammation, Suppurative            |       2                                                           1      |             
      Prepuce, Inflammation, Chronic       |                4                                                         |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Spinal Cord                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration                         |                1  1  1  1  1  1     1  1  1  1     1  1  1        1  1  1|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |    1                                                                     |             
      Alveolar Epithelium, Hyperplasia     |          4                                                               |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Turbinate, Olfactory Epithelium,     |                                                                          |             
           Degeneration                    |             2                       1                                    |             
                                           |__________________________________________________________________________|             
   Trachea                                 |    +  +                                                                  |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     |    +  +                                                                  |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  16                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 0| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
                             DAY ON TEST   | 7| 1| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                                           | 3| 6| 9| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE 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|             
    70 PPM                                 | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|             
                                           | 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                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Zymbal's Gland                          |    +  +                                                                  |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  |    +  +        +                                                         |             
      Bilateral, Hydronephrosis            |                1                                                         |             
      Bilateral, Pelvis, Inflammation,     |                                                                          |             
           Suppurative                     |       1                                                                  |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         |    +  +        +                          +                              |             
      Calculus Micro Observation Only      |                X                                                         |             
      Dilatation                           |                3                          2                              |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  17                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 3| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8|                             |            |
                                           | 3| 3| 3| 3| 3| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      A     |
    70 PPM                                 | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               |                +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             |                +  M  +  +  +  +  +  +  +  +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  |                +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 |                +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  |                +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               |                +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                |                +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  |                +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Basophilic Focus                     |                                                                          |      1     |
      Infarct                              |                                                                          |      1  4.0|
      Vacuolization Cytoplasmic            | 2  1  1  1  1     2           1                                          |     25  1.2|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   2        |
      Necrosis                             |                                                                          |      2  2.0|
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Focal Cellular Change                |          2                                                               |      1  2.0|
      Inflammation, Chronic                |                                                                          |      2  1.0|
      Duct, Cyst                           |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Pharynx                                 |                +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         |                +  +  +  +  +  +  +  +  +  +                              |  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  18                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 3| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8|                             |            |
                                           | 3| 3| 3| 3| 3| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      A     |
    70 PPM                                 | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Epithelium, Hyperplasia              |    2                                                                     |      2  2.0|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hyperplasia                          |                                                                          |      1  2.0|
      Inflammation, Suppurative            |                               2                                          |      1  2.0|
      Pigmentation, Hemosiderin            |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Tongue                                  |                +  +  +  +  +  +  +  +  +  +                              |  12        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            |                +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Heart                                   |                +  +  +  +  +  +  +  +  +  +                              |  12        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          |                +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         |                +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hyperplasia                          |    1                                                                     |      9  1.2|
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       |                +  M  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         |                +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           |                +  +  +  +  +  +  +  +  +  +                              |  12        |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                             Page  19                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 3| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8|                             |            |
                                           | 3| 3| 3| 3| 3| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      A     |
    70 PPM                                 | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              |                +  +  +  +  +  +  +  +  +  +                              |  12        |
      Inflammation                         |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         |    +           +  +  +  +  +  +  +  +  +  +                              |  13        |
      Hemorrhage                           |                                                                          |      1  3.0|
      Inflammation, Suppurative            |                               4                                          |      3  2.3|
      Necrosis                             |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Prostate                                |                +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         |                +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             |                +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |                                                                          |   1        |
      Iliac, Hyperplasia                   |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   |                +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  |                +  +  +  M  M  +  +  +  M  M                              |   7        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  |                +  +  +  +  +  +  +  +  +  +                              |  13        |
      Hyperplasia                          |                                                                          |      1  2.0|
      Necrosis                             |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 |                +  M  +  +  +  +  +  +  M  +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Spleen                                  |                +  +  +  +  +  +  +  +  +  +                              |  15        |
      Accessory Spleen                     |                                                                          |      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  20                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 3| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8|                             |            |
                                           | 3| 3| 3| 3| 3| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      A     |
    70 PPM                                 | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
      Hematopoietic Cell Proliferation     |                                                                          |      1  2.0|
      Necrosis                             |                                                                          |      1  2.0|
      Pigmentation, Melanin                |                1                                                         |      3  1.7|
                                           |__________________________________________________________________________|____________|
   Thymus                                  |                +  +  +  +  +  +  +  +  +  +                              |  12        |
      Necrosis                             |                                                                          |      2  3.0|
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           |                M  M  M  M  M  M  M  M  M  M                              |            |
                                           |__________________________________________________________________________|____________|
   Skin                                    |                +  +  +  +  +  +  +  +  +  +                              |  14        |
      Hemorrhage                           |                                                                          |      1  2.0|
      Inflammation, Suppurative            |                                                                          |      2  1.5|
      Prepuce, Inflammation, Chronic       |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    |                +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   |                +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Degeneration                         | 1     1  1  1                                                            |     20  1.0|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  |                +  +  +  +  +  +  +  +  +  +                              |  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  21                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 3| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8|                             |            |
                                           | 3| 3| 3| 3| 3| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      A     |
    70 PPM                                 | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hemorrhage                           |             1                                                            |      2  1.0|
      Alveolar Epithelium, Hyperplasia     |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Turbinate, Olfactory Epithelium,     |                                                                          |            |
           Degeneration                    |                                                                          |      2  1.5|
                                           |__________________________________________________________________________|____________|
   Trachea                                 |                +  +  +  +  +  +  +  +  +  +                              |  12        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     |                +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Zymbal's Gland                          |                +  +  +  +  +  +  +  +  +  +                              |  12        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  |                +  +  +  +  +  +  +  +  +  +                              |  13        |
      Bilateral, Hydronephrosis            |                                                                          |      1  1.0|
      Bilateral, Pelvis, Inflammation,     |                                                                          |            |
           Suppurative                     |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         |             +  +  +  +  +  +  +  +  +  +  +                              |  15        |
      Calculus Micro Observation Only      |                                                                          |      1     |
      Dilatation                           |                                                                          |      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  22                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
                             DAY ON TEST   | 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                                           | 2| 2| 2| 2| 0| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|             
    220 PPM                                | 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0|             
                                           | 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                               |             A                                                            |             
                                           |__________________________________________________________________________|             
   Gallbladder                             |             A                                                            |             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  |             A                                                            |             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 |             A                                                            |             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  |             A                                                            |             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               |             A                                                            |             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                |             A                                                            |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  |             A                                                            |             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basophilic Focus                     |                         X                                                |             
      Mixed Cell Focus                     |                                                                X         |             
      Necrosis                             |                                                                         1|             
      Vacuolization Cytoplasmic            | 1  1  2  1     1  1  1  1  1  1  1  1  1  2  1  2  2  1     1  1        1|             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pharynx                                 |             +                                                            |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         |             A                                                            |             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infiltration Cellular, Mast Cell     |                                     2                                    |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Tongue                                  |             +                                                            |             
                                           |__________________________________________________________________________|             
   Tooth                                   |                                                       +                  |             
      Deformity                            |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  23                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
                             DAY ON TEST   | 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                                           | 2| 2| 2| 2| 0| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|             
    220 PPM                                | 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0|             
                                           | 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|             
 __________________________________________|__________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            |             A                                                            |             
                                           |__________________________________________________________________________|             
   Heart                                   |             A                                                            |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          |             A                                                            |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         |             A                                                            |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          | 3     1           1  1     2        2     2  2  1                        |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       |             A                                                            |             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         |             A                                                            |             
      Pars Distalis, Cyst                  |                                                                          |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           |             A                                                            |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              |             A                                                            |             
                                           |__________________________________________________________________________|             
   Preputial Gland                         |             A                                                            |             
                                           |__________________________________________________________________________|             
   Prostate                                |             A                                                            |             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         |             A                                                            |             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  24                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
                             DAY ON TEST   | 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                                           | 2| 2| 2| 2| 0| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|             
    220 PPM                                | 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0|             
                                           | 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               |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             |             A                                                            |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   |             A                                                            |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  |             A                                                            |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  |             A                                                            |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 |             A                                                            |             
                                           |__________________________________________________________________________|             
   Spleen                                  |             A                                                            |             
                                           |__________________________________________________________________________|             
   Thymus                                  |             A                                                            |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           |             A                                                            |             
                                           |__________________________________________________________________________|             
   Skin                                    |             A                                                            |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    |             A                             +                              |             
      Osteopetrosis                        |                                           1                              |             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   |             A                                                            |             
      Cyst Epithelial Inclusion            |                                                                          |             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Spinal Cord                             | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration                         | 1        1     1     1  1     1  1  1     1     1  1  1     1  1  1  1   |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  25                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
                             DAY ON TEST   | 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                                           | 2| 2| 2| 2| 0| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|             
    220 PPM                                | 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0|             
                                           | 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                     |                                                                          |             
      Meninges, Cyst Epithelial Inclusion  |                                                          X               |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  |             A                                                            |             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                                          2           2   |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Turbinate, Inflammation              |                                                       1                  |             
      Turbinate, Olfactory Epithelium,     |                                                                          |             
           Degeneration                    |       1                 1                    1  1                        |             
                                           |__________________________________________________________________________|             
   Trachea                                 |             A                                                            |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     |             +                                                            |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Zymbal's Gland                          |             +                                                            |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  |             A                                                            |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         |             A                                                            |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  26                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 3| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 0| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8|                             |            |
                                           | 9| 2| 2| 2| 2| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |      A     |
    220 PPM                                | 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +              +  +  +  +  +  +  +  M  +  +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +              +  +  M  +  +  +  +  +  +  +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
      Basophilic Focus                     |                                           3                              |      2  3.0|
      Mixed Cell Focus                     |                                                                          |      1     |
      Necrosis                             |                                                                          |      1  1.0|
      Vacuolization Cytoplasmic            |    1     1  1  1              1     1                                    |     27  1.1|
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
                                           |__________________________________________________________________________|____________|
   Pharynx                                 | +              +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
      Infiltration Cellular, Mast Cell     |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  27                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 3| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 0| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8|                             |            |
                                           | 9| 2| 2| 2| 2| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |      A     |
    220 PPM                                | 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
   Tongue                                  | +              +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Tooth                                   | +                                                                        |   2        |
      Deformity                            | X                                                                        |      1     |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            | M              +  +  +  +  +  +  +  +  +  +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
      Hyperplasia                          |    2     1  1                                                            |     12  1.6|
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | M              +  +  +  +  +  +  M  +  M  +                              |   8        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +              M  +  +  +  +  +  +  +  +  +                              |  10        |
      Pars Distalis, Cyst                  | X                                                                        |      1     |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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  28                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 3| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 0| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8|                             |            |
                                           | 9| 2| 2| 2| 2| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |      A     |
    220 PPM                                | 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 GENITAL SYSTEM - cont                     |                                                                          |            |
   Preputial Gland                         | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Prostate                                | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
      Atrophy                              |                   1                                                      |      1  1.0|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +              +  +  +  +  +  +  +  M  +  +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | M              +  +  +  +  +  +  +  +  +  +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +              +  +  +  +  +  +  +  M  M  +                              |   9        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +              M  +  M  +  +  +  M  M  +  +                              |   7        |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | M              M  M  M  M  M  M  M  M  M  M                              |            |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +              +  +  +  +  +  +  +  +  +  +                              |  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  29                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 3| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 0| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8|                             |            |
                                           | 9| 2| 2| 2| 2| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |      A     |
    220 PPM                                | 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 MUSCULOSKELETAL SYSTEM - cont             |                                                                          |            |
      Osteopetrosis                        |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
      Inflammation                         |                            2                                             |      1  2.0|
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
      Cyst Epithelial Inclusion            |                         X                                                |      1     |
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
      Degeneration                         |       1  1  1                                                            |     19  1.0|
      Meninges, Cyst Epithelial Inclusion  |                                                                          |      1     |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
      Hemorrhage                           |                                                                          |      2  2.0|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
      Turbinate, Inflammation              |                                                                          |      1  1.0|
      Turbinate, Olfactory Epithelium,     |                                                                          |            |
           Degeneration                    |    1                                                                     |      5  1.0|
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +              +  +  +  +  +  +  +  +  +  +                              |  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  30                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 3| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 0| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8|                             |            |
                                           | 9| 2| 2| 2| 2| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |      A     |
    220 PPM                                | 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 SPECIAL SENSES SYSTEM - cont              |                                                                          |            |
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
      Hyperplasia                          | 3     1                          1                                       |      3  1.7|
                                           |__________________________________________________________________________|____________|
   Zymbal's Gland                          | +              +  +  +  +  +  +  +  +  +  +                              |  12        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +              +  +  +  +  +  +  +  +  +  +                              |  11        |
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
  * : 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: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
                             DAY ON TEST   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 2| 7|             
                                           | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 7| 2| 2| 2| 2| 2| 2| 2| 2| 2| 4| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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|             
    700 PPM                                | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               |                                        +                             +   |             
                                           |__________________________________________________________________________|             
   Gallbladder                             |                                        +                             A   |             
      Inflammation, Suppurative            |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  |                                        +                             +   |             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 |                                        +                             +   |             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  |                                        +        +                    +   |             
      Parasite                             |                                                 X                        |             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               |                                        A                             +   |             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                |                                        +                             +   |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  |                                        +                             +   |             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                      1                                         3         |             
      Basophilic Focus                     |                                                    X                     |             
      Clear Cell Focus                     |                                              1              2            |             
      Eosinophilic Focus                   |             3           2  2  2           1                              |             
      Mixed Cell Focus                     |                                                          1               |             
      Necrosis                             |                                        2                                 |             
      Vacuolization Cytoplasmic            | 1        1  1  1  1        2  1                 1  1  1  1  1  1         |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                                        +     +                           |             
      Angiectasis                          |                                        1                                 |             
      Necrosis                             |                                        2     3                           |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Focal Cellular Change                |       1        1                    1                 1                  |             
                                           |__________________________________________________________________________|             
   Pharynx                                 |                                        +                             +   |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         |                                        +                             +   |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  32                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
                             DAY ON TEST   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 2| 7|             
                                           | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 7| 2| 2| 2| 2| 2| 2| 2| 2| 2| 4| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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|             
    700 PPM                                | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4|             
                                           | 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                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Epithelium, Hyperplasia              |                         1        1                    2  2           1   |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |          1                    1                 X                        |             
      Inflammation, Suppurative            |                                                                      1   |             
      Pigmentation, Hemosiderin            |                                        2                                 |             
      Ulcer                                |                                        2                                 |             
                                           |__________________________________________________________________________|             
   Tongue                                  |                                        +                             +   |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            |                                        +                             +   |             
                                           |__________________________________________________________________________|             
   Heart                                   |                                        +                             +   |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          |                                        +                             +   |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         |                                        +                             +   |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |          1  1     1  1     2              1  3  2  1  1  1               |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       |                                        +                             +   |             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         |                                        +                             +   |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           |                                        +                             +   |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  33                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
                             DAY ON TEST   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 2| 7|             
                                           | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 7| 2| 2| 2| 2| 2| 2| 2| 2| 2| 4| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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|             
    700 PPM                                | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4|             
                                           | 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                     |                                                                          |             
   Epididymis                              |                                        +                             +   |             
                                           |__________________________________________________________________________|             
   Preputial Gland                         |                                        +  +           +           +  +   |             
      Angiectasis                          |                                                                   3      |             
      Inflammation, Chronic                |                                           3                              |             
                                           |__________________________________________________________________________|             
   Prostate                                |                                        +                             +   |             
      Inflammation, Suppurative            |                                        2                             3   |             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         |                                        +                             +   |             
      Inflammation, Suppurative            |                                                                      3   |             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             |                                        +                             +   |             
      Hyperplasia                          |                                                                      2   |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   |                                        +                             M   |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  |                                        +                             +   |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  |                                     +  M                             +   |             
      Hyperplasia                          |                                     3                                    |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 |                                        +                             +   |             
                                           |__________________________________________________________________________|             
   Spleen                                  |                                        +                             +   |             
      Infiltration Cellular, Histiocyte    |                                                                      2   |             
      Pigmentation, Melanin                |                                                                          |             
                                           |__________________________________________________________________________|             
   Thymus                                  |                                        +                             +   |             
      Atrophy                              |                                                                      3   |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           |                                        M                             M   |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  34                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
                             DAY ON TEST   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 2| 7|             
                                           | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 7| 2| 2| 2| 2| 2| 2| 2| 2| 2| 4| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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|             
    700 PPM                                | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |__________________________________________________________________________|             
   Skin                                    |                                        +                             +   |             
      Prepuce, Inflammation, Chronic       |                                                                      3   |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    |                                        +                             +   |             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   |                                        +                             +   |             
      Hemorrhage                           |                                        2                                 |             
      Necrosis                             |                                                                          |             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Sciatic, Degeneration                |                                                       1                  |             
                                           |__________________________________________________________________________|             
   Spinal Cord                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration                         | 1     1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  |                                        +                             +   |             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                                        3                                 |             
      Thrombosis                           |                                                                          |             
      Alveolar Epithelium, Hyperplasia     |    2                                2                       4            |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Turbinate, Inflammation              |          1                                                               |             
      Turbinate, Olfactory Epithelium,     |                                                                          |             
           Degeneration                    |       1  1     1  1  1     1  1              1  1  1                     |             
                                           |__________________________________________________________________________|             
   Trachea                                 |                                        +                             +   |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  35                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 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|             
                             DAY ON TEST   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 2| 7|             
                                           | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 7| 2| 2| 2| 2| 2| 2| 2| 2| 2| 4| 2|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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|             
    700 PPM                                | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4|             
                                           | 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                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     |                                        +                             +   |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                        2                             1   |             
                                           |__________________________________________________________________________|             
   Zymbal's Gland                          |                                        +                             +   |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  |                   +                    +                             +   |             
      Bilateral, Hydronephrosis            |                                        4                                 |             
      Bilateral, Cortex, Pelvis,           |                                                                          |             
          Inflammation, Suppurative        |                                                                      3   |             
      Bilateral, Pelvis, Inflammation,     |                                                                          |             
           Suppurative                     |                                        2                                 |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         |                                        +                             +   |             
      Dilatation                           |                                                                      2   |             
      Transitional Epithelium, Hyperplasia |                                                                      1   |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  36                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 7| 8| 8|                             |            |
                                           | 2| 2| 2| 2| 5| 5| 5| 5| 5| 5| 5| 5| 6| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |      A     |
    700 PPM                                | 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             |             +  +  +  +  +  +  +  +  +  +  +                              |  12        |
      Inflammation, Suppurative            |                               1                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  |             +  +  +  +  +  +  +  +  +  +  +                              |  14        |
      Parasite                             |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               |             +  +  +  +  +  +  +  +  +  +  +                              |  12        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Angiectasis                          |                                                                          |      2  2.0|
      Basophilic Focus                     |    2              4                       X                              |      4  3.0|
      Clear Cell Focus                     |                                                                          |      2  1.5|
      Eosinophilic Focus                   | 3                                                                        |      6  2.2|
      Mixed Cell Focus                     |                                                                          |      1  1.0|
      Necrosis                             |                                                                          |      1  2.0|
      Vacuolization Cytoplasmic            |    1  1  1     2     1     1     2                                       |     20  1.2|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   2        |
      Angiectasis                          |                                                                          |      1  1.0|
      Necrosis                             |                                                                          |      2  2.5|
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Focal Cellular Change                |       1                                                                  |      5  1.0|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  37                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 7| 8| 8|                             |            |
                                           | 2| 2| 2| 2| 5| 5| 5| 5| 5| 5| 5| 5| 6| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |      A     |
    700 PPM                                | 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Pharynx                                 |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Epithelium, Hyperplasia              | 2        1  3  3  2  4  4  2     2  4  1                                 |     16  2.2|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hyperplasia                          |                                                                          |      3  1.0|
      Inflammation, Suppurative            |                                                                          |      1  1.0|
      Pigmentation, Hemosiderin            |                                                                          |      1  2.0|
      Ulcer                                |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Tongue                                  |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
                                           |__________________________________________________________________________|____________|
   Heart                                   |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hyperplasia                          | 1                                                                        |     12  1.3|
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       |             M  M  +  +  +  +  +  +  +  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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  38                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 7| 8| 8|                             |            |
                                           | 2| 2| 2| 2| 5| 5| 5| 5| 5| 5| 5| 5| 6| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |      A     |
    700 PPM                                | 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         |             +  +  +  +  +  +  +  +  +  +  +                              |  16        |
      Angiectasis                          |                                                                          |      1  3.0|
      Inflammation, Chronic                |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Prostate                                |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
      Inflammation, Suppurative            |                                                                          |      2  2.5|
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
      Inflammation, Suppurative            |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
      Hyperplasia                          |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   |             +  +  +  +  +  +  +  +  +  M  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  |             +  +  +  +  +  +  M  +  M  +  +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
      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  39                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 7| 8| 8|                             |            |
                                           | 2| 2| 2| 2| 5| 5| 5| 5| 5| 5| 5| 5| 6| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |      A     |
    700 PPM                                | 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
   Lymph Node, Mediastinal                 |             M  +  M  +  +  M  +  +  +  M  +                              |   9        |
                                           |__________________________________________________________________________|____________|
   Spleen                                  |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
      Infiltration Cellular, Histiocyte    |                                                                          |      1  2.0|
      Pigmentation, Melanin                |                               2                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
      Atrophy                              |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           |             M  M  M  M  M  M  M  M  M  M  M                              |            |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +           +  +  +  +  +  +  +  +  +  +  +                              |  14        |
      Prepuce, Inflammation, Chronic       |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
      Hemorrhage                           |                                     1                                    |      2  1.5|
      Necrosis                             |                                     2                                    |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
      Sciatic, Degeneration                |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Degeneration                         | 1  1  1  1                                                               |     28  1.0|
 _____________________________________________________________________________________________________________________|            |
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                             Page  40                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 7| 8| 8|                             |            |
                                           | 2| 2| 2| 2| 5| 5| 5| 5| 5| 5| 5| 5| 6| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |      A     |
    700 PPM                                | 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hemorrhage                           |                                                                          |      1  3.0|
      Thrombosis                           |                                     2                                    |      1  2.0|
      Alveolar Epithelium, Hyperplasia     |                                                                          |      3  2.7|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Turbinate, Inflammation              |                                                                          |      1  1.0|
      Turbinate, Olfactory Epithelium,     |                                                                          |            |
           Degeneration                    |          1  1                                                            |     12  1.0|
                                           |__________________________________________________________________________|____________|
   Trachea                                 |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hyperplasia                          |                                                                          |      2  1.5|
                                           |__________________________________________________________________________|____________|
   Zymbal's Gland                          |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  |             +  +  +  +  +  +  +  +  +  +  +                              |  14        |
      Bilateral, Hydronephrosis            |                                                                          |      1  4.0|
      Bilateral, Cortex, Pelvis,           |                                                                          |            |
          Inflammation, Suppurative        |                                                                          |      1  3.0|
      Bilateral, Pelvis, Inflammation,     |                                                                          |            |
           Suppurative                     |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         |             +  +  +  +  +  +  +  +  +  +  +                              |  13        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  41                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |            |
                             DAY ON TEST   | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 7| 8| 8|                             |            |
                                           | 2| 2| 2| 2| 5| 5| 5| 5| 5| 5| 5| 5| 6| 5| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|                             |      A     |
    700 PPM                                | 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 URINARY SYSTEM - cont                     |                                                                          |            |
      Dilatation                           |                                                                          |      1  2.0|
      Transitional Epithelium, Hyperplasia |                                                                          |      1  1.0|
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  42                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 1| 1| 1| 1| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 1| 3| 3| 1| 2| 1| 1| 3|             
                             DAY ON TEST   | 7| 7| 6| 8| 3| 8| 7| 7| 7| 7| 8| 7| 7| 7| 7| 7| 7| 8| 2| 7| 8| 8| 8| 8| 7|             
                                           | 1| 1| 0| 5| 6| 5| 1| 1| 1| 1| 5| 1| 1| 1| 1| 1| 1| 5| 6| 1| 5| 9| 5| 5| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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|             
    2200 PPM                               | 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8|             
                                           | 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                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  A  +  +  +|             
      Inflammation, Suppurative            |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  A  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  A  +  +  +|             
      Serosa, Inflammation, Chronic        |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  A  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  A  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Basophilic Focus                     |                         2        2           2           X               |             
      Eosinophilic Focus                   |                                  3           4  2                        |             
      Hematopoietic Cell Proliferation     |                                                       2                  |             
      Hyperplasia, Focal                   |                                              4                           |             
      Inflammation, Chronic                |                                        2                                 |             
      Mixed Cell Focus                     |                            2                                             |             
      Vacuolization Cytoplasmic            | 1  1              1  1  1  2     1     1  1  1  1  1     1  1            |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                      +                                +        +         |             
      Necrosis                             |                      2                                                   |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Focal Cellular Change                |                            1                                             |             
      Inflammation, Chronic                |                      1                                                   |             
                                           |__________________________________________________________________________|             
   Pharynx                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  43                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 1| 1| 1| 1| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 1| 3| 3| 1| 2| 1| 1| 3|             
                             DAY ON TEST   | 7| 7| 6| 8| 3| 8| 7| 7| 7| 7| 8| 7| 7| 7| 7| 7| 7| 8| 2| 7| 8| 8| 8| 8| 7|             
                                           | 1| 1| 0| 5| 6| 5| 1| 1| 1| 1| 5| 1| 1| 1| 1| 1| 1| 5| 6| 1| 5| 9| 5| 5| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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|             
    2200 PPM                               | 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                   2                                                      |             
      Epithelium, Hyperplasia              |    3  4  4     4              3  1  2  2        1  2        4     3  4  3|             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
      Hyperplasia                          |                                              1           2               |             
                                           |__________________________________________________________________________|             
   Tongue                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +|             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     |                                                       2                  |             
      Hyperplasia                          | 1  1                    1                 1                              |             
      Hypertrophy, Focal                   |    1                                         2                           |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          | 1                 2  1  1  1           1     1  1        1               |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  M  M  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  M  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +|             
      Cyst                                 |                                                                          |             
      Follicular Cell, Hyperplasia         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                             Page  44                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 1| 1| 1| 1| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 1| 3| 3| 1| 2| 1| 1| 3|             
                             DAY ON TEST   | 7| 7| 6| 8| 3| 8| 7| 7| 7| 7| 8| 7| 7| 7| 7| 7| 7| 8| 2| 7| 8| 8| 8| 8| 7|             
                                           | 1| 1| 0| 5| 6| 5| 1| 1| 1| 1| 5| 1| 1| 1| 1| 1| 1| 5| 6| 1| 5| 9| 5| 5| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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|             
    2200 PPM                               | 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
      Atrophy                              |                                                       4                  |             
      Inflammation, Suppurative            |                         1                                                |             
                                           |__________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |    1                                                                     |             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                         4|             
      Hyperplasia                          |                                                       3                  |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  M  +  +  +  +  +  M  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  M  +  M  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | M  M  +  M  M  +  +  M  M  M  +  M  +  +  +  M  +  +  +  M  M  +  +  M  M|             
      Hyperplasia                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     |                                                       3                  |             
      Pigmentation, Melanin                |                                                             1            |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                                                       3                  |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  45                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 1| 1| 1| 1| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 1| 3| 3| 1| 2| 1| 1| 3|             
                             DAY ON TEST   | 7| 7| 6| 8| 3| 8| 7| 7| 7| 7| 8| 7| 7| 7| 7| 7| 7| 8| 2| 7| 8| 8| 8| 8| 7|             
                                           | 1| 1| 0| 5| 6| 5| 1| 1| 1| 1| 5| 1| 1| 1| 1| 1| 1| 5| 6| 1| 5| 9| 5| 5| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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|             
    2200 PPM                               | 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst Epithelial Inclusion            | X                                                                        |             
      Hemorrhage                           |                                                                3         |             
      Prepuce, Inflammation, Chronic       |                                                                4         |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Mineralization                       |                         1                                                |             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  A  +  +  +|             
      Sciatic, Degeneration                |                                     2                                    |             
                                           |__________________________________________________________________________|             
   Spinal Cord                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
      Degeneration                         |                   1                 1  1     1     1                    1|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |       2                                                                  |             
      Alveolar Epithelium, Hyperplasia     |                      2              1           2           2            |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Turbinate, Olfactory Epithelium,     |                                                                          |             
           Degeneration                    | 1  1  1           2  1  1  2  1  1  1  1     2  1     1  2              1|             
      Turbinate, Olfactory Epithelium,     |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  46                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 1| 1| 1| 1| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 1| 3| 3| 1| 2| 1| 1| 3|             
                             DAY ON TEST   | 7| 7| 6| 8| 3| 8| 7| 7| 7| 7| 8| 7| 7| 7| 7| 7| 7| 8| 2| 7| 8| 8| 8| 8| 7|             
                                           | 1| 1| 0| 5| 6| 5| 1| 1| 1| 1| 5| 1| 1| 1| 1| 1| 1| 5| 6| 1| 5| 9| 5| 5| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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|             
    2200 PPM                               | 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8|             
                                           | 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, Chronic           |                   1                                                      |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                               1                       1                  |             
                                           |__________________________________________________________________________|             
   Zymbal's Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Bilateral, Hydronephrosis            |                                                                      2   |             
      Bilateral, Metaplasia, Osseous       |                                                                          |             
      Bilateral, Renal Tubule, Hyperplasia |                                        1  1                              |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  47                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 3| 1|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 7| 7| 7| 8| 7| 7| 7| 7| 8|                             |            |
                                           | 5| 1| 1| 1| 1| 1| 1| 1| 1| 5| 1| 1| 1| 1| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|                             |      A     |
    2200 PPM                               | 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  37        |
      Inflammation, Suppurative            |                         1                                                |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  38        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  37        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  37        |
      Serosa, Inflammation, Chronic        |                                        2                                 |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  38        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  37        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Angiectasis                          |          1                                                               |      1  1.0|
      Basophilic Focus                     |          4                                                               |      5  2.5|
      Eosinophilic Focus                   |    4                                   4                                 |      5  3.4|
      Hematopoietic Cell Proliferation     |                                        2                                 |      2  2.0|
      Hyperplasia, Focal                   |                                                                          |      1  4.0|
      Inflammation, Chronic                |                                                                          |      1  2.0|
      Mixed Cell Focus                     |                         1                                                |      2  1.5|
      Vacuolization Cytoplasmic            | 1     1  2  1  1  2  1  1        1  1                                    |     24  1.1|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                   +                                                      |   4        |
      Necrosis                             |                   2                                                      |      2  2.0|
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Focal Cellular Change                |    1                                   1                                 |      3  1.0|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  48                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 3| 1|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 7| 7| 7| 8| 7| 7| 7| 7| 8|                             |            |
                                           | 5| 1| 1| 1| 1| 1| 1| 1| 1| 5| 1| 1| 1| 1| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|                             |      A     |
    2200 PPM                               | 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
      Inflammation, Chronic                |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Pharynx                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Angiectasis                          |                         1                                                |      2  1.5|
      Epithelium, Hyperplasia              | 3              1           2  2           4                              |     19  2.7|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  38        |
      Hyperplasia                          |                                                                          |      2  1.5|
                                           |__________________________________________________________________________|____________|
   Tongue                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  38        |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
      Hematopoietic Cell Proliferation     |                                                                          |      1  2.0|
      Hyperplasia                          |       1  1  1                 1                                          |      8  1.0|
      Hypertrophy, Focal                   |          1  1        1        1                                          |      6  1.2|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hyperplasia                          |    1     1  1  2  1  3  1                                                |     16  1.3|
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | M  +  +  +  M  +  M  +  +  +  M  +  +  +  +                              |  32        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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  49                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 3| 1|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 7| 7| 7| 8| 7| 7| 7| 7| 8|                             |            |
                                           | 5| 1| 1| 1| 1| 1| 1| 1| 1| 5| 1| 1| 1| 1| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|                             |      A     |
    2200 PPM                               | 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | M  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  37        |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
      Cyst                                 |                                     X                                    |      1     |
      Follicular Cell, Hyperplasia         |                   1                                                      |      1  1.0|
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
      Atrophy                              |                                                                          |      1  4.0|
      Inflammation, Suppurative            |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  M  +  +  +  +  +  +  +  +  +  +                              |  39        |
      Hyperplasia                          |                         2                                                |      2  1.5|
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Angiectasis                          |                                                                          |      1  4.0|
      Hyperplasia                          |                                        3                                 |      2  3.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  +  +  +  +  +  M  M  +  +  +  +  +  +  +                              |  35        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  M  +  +  +  M                              |  33        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  50                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 3| 1|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 7| 7| 7| 8| 7| 7| 7| 7| 8|                             |            |
                                           | 5| 1| 1| 1| 1| 1| 1| 1| 1| 5| 1| 1| 1| 1| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|                             |      A     |
    2200 PPM                               | 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
      Hyperplasia                          |                                        4                                 |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  M  M  M  M  M  M  +  +  +  +  +  +  +  M                              |  20        |
      Hyperplasia                          |                                        3                                 |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hematopoietic Cell Proliferation     |                                        4                                 |      2  3.5|
      Pigmentation, Melanin                |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
      Atrophy                              |                                                                          |      1  3.0|
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M                              |            |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Cyst Epithelial Inclusion            |                                                                          |      1     |
      Hemorrhage                           |                                                                          |      1  3.0|
      Prepuce, Inflammation, Chronic       |                      3                                                   |      2  3.5|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Inflammation                         |                            1                                             |      1  1.0|
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Mineralization                       |          1                                                               |      2  1.0|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  51                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 3| 1|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 7| 7| 7| 8| 7| 7| 7| 7| 8|                             |            |
                                           | 5| 1| 1| 1| 1| 1| 1| 1| 1| 5| 1| 1| 1| 1| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|                             |      A     |
    2200 PPM                               | 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 NERVOUS SYSTEM - cont                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  38        |
      Sciatic, Degeneration                |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
      Degeneration                         |    1  1  1  1  1  1  1  1     1  1  1  1                                 |     18  1.0|
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  38        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hemorrhage                           |                                  1                                       |      2  1.5|
      Alveolar Epithelium, Hyperplasia     |                2                                                         |      5  1.8|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Turbinate, Olfactory Epithelium,     |                                                                          |            |
           Degeneration                    |    1  1        2  2  1  2     1  1  1  2                                 |     26  1.3|
      Turbinate, Olfactory Epithelium,     |                                                                          |            |
           Inflammation, Chronic           |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hyperplasia                          |                3                                                         |      3  1.7|
                                           |__________________________________________________________________________|____________|
   Zymbal's Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 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  52                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 3| 1|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 7| 7| 7| 8| 7| 7| 7| 7| 8|                             |            |
                                           | 5| 1| 1| 1| 1| 1| 1| 1| 1| 5| 1| 1| 1| 1| 5|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|                             |      A     |
    2200 PPM                               | 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 URINARY SYSTEM - cont                     |                                                                          |            |
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Bilateral, Hydronephrosis            |                                                                          |      1  2.0|
      Bilateral, Metaplasia, Osseous       |                      1                                                   |      1  1.0|
      Bilateral, Renal Tubule, Hyperplasia |                                                                          |      2  1.0|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  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  53                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 1| 3| 1| 1| 1| 1| 1| 3| 1| 1| 1| 3| 3| 1| 3| 2| 3| 3| 3| 3| 3| 1| 1| 3|             
                             DAY ON TEST   | 7| 2| 7| 8| 8| 2| 2| 8| 1| 4| 8| 8| 7| 7| 8| 7| 0| 7| 7| 7| 7| 7| 8| 8| 7|             
                                           | 1| 3| 1| 5| 5| 8| 3| 3| 7| 6| 5| 3| 1| 1| 5| 1| 9| 1| 1| 1| 1| 1| 3| 5| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    7000 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                               | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | +  A  +  +  +  +  A  +  +  +  +  +  M  +  M  M  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  A  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  A  +  +  +  +  A  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  A  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Parasite                             |                                                    X                     |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  A  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Parasite                             |                                                    X                     |             
                                           |__________________________________________________________________________|             
   Liver                                   | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |       2                 1                                                |             
      Basophilic Focus                     |       4                       4        4              2                  |             
      Clear Cell Focus                     |                                                                          |             
      Eosinophilic Focus                   |       2                                      X              2            |             
      Hematopoietic Cell Proliferation     |                                                          1               |             
      Mixed Cell Focus                     |                                        2     2                           |             
      Necrosis                             |                1                                         1               |             
      Vacuolization Cytoplasmic            |       2  2     1              1     1  1  2        2  2     2           2|             
      Bile Duct, Hyperplasia               |                         2                                                |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                                        +                                 |             
      Necrosis                             |                                        4                                 |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Focal Cellular Change                | 1     2                                1           1  1                  |             
      Inflammation, Chronic                |                                                                          |             
      Duct, Cyst                           |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  54                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 1| 3| 1| 1| 1| 1| 1| 3| 1| 1| 1| 3| 3| 1| 3| 2| 3| 3| 3| 3| 3| 1| 1| 3|             
                             DAY ON TEST   | 7| 2| 7| 8| 8| 2| 2| 8| 1| 4| 8| 8| 7| 7| 8| 7| 0| 7| 7| 7| 7| 7| 8| 8| 7|             
                                           | 1| 3| 1| 5| 5| 8| 3| 3| 7| 6| 5| 3| 1| 1| 5| 1| 9| 1| 1| 1| 1| 1| 3| 5| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    7000 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                  |                                                                          |             
                                           |__________________________________________________________________________|             
   Pharynx                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Epithelium, Hyperplasia              |          3  2     2        4  4  3        2                       2  4  4|             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  A  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                     2                    2              1|             
      Inflammation, Suppurative            |                                     1              2                     |             
      Necrosis                             |                1           2                                             |             
                                           |__________________________________________________________________________|             
   Tongue                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Heart                                   | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Focal                   |                                                                          |             
      Hyperplasia                          |       1                                            2     1  1  1         |             
      Hypertrophy, Focal                   | 1                                   1                                   1|             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Angiectasis                          |                                                                          |             
      Hyperplasia                          | 1     1                                2     1     1  1  1  1            |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  M  +  M  +  +  +  +  +  +  +  +  +  M  +  +  M  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  55                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 1| 3| 1| 1| 1| 1| 1| 3| 1| 1| 1| 3| 3| 1| 3| 2| 3| 3| 3| 3| 3| 1| 1| 3|             
                             DAY ON TEST   | 7| 2| 7| 8| 8| 2| 2| 8| 1| 4| 8| 8| 7| 7| 8| 7| 0| 7| 7| 7| 7| 7| 8| 8| 7|             
                                           | 1| 3| 1| 5| 5| 8| 3| 3| 7| 6| 5| 3| 1| 1| 5| 1| 9| 1| 1| 1| 1| 1| 3| 5| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    7000 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                           | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                        4                                 |             
      Inflammation                         |                                        1                                 |             
                                           |__________________________________________________________________________|             
   Penis                                   |    +              +                                                      |             
                                           |__________________________________________________________________________|             
   Preputial Gland                         | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M|             
      Angiectasis                          |                                                                          |             
      Atrophy                              |                                                 4                        |             
      Inflammation, Chronic                |                                                       2                  |             
                                           |__________________________________________________________________________|             
   Prostate                                | +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M|             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                      1     1                    3                 2  2   |             
      Mineralization                       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          | 2                                               2        3               |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  M  M  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  M  +  +  +  M  +  +  +  M  +  +  +  M  +  +  +  M  M  +  +  M  M  +  M|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  56                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 1| 3| 1| 1| 1| 1| 1| 3| 1| 1| 1| 3| 3| 1| 3| 2| 3| 3| 3| 3| 3| 1| 1| 3|             
                             DAY ON TEST   | 7| 2| 7| 8| 8| 2| 2| 8| 1| 4| 8| 8| 7| 7| 8| 7| 0| 7| 7| 7| 7| 7| 8| 8| 7|             
                                           | 1| 3| 1| 5| 5| 8| 3| 3| 7| 6| 5| 3| 1| 1| 5| 1| 9| 1| 1| 1| 1| 1| 3| 5| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    7000 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, Mediastinal                 | M  M  M  M  M  M  +  M  +  M  +  +  M  +  M  +  +  +  +  +  +  M  +  M  +|             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hematopoietic Cell Proliferation     | 1                                                        3  2            |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  M  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Necrosis                             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            |                                                 1                        |             
      Prepuce, Inflammation, Chronic       | 4                                                                        |             
      Sebaceous Gland, Hyperplasia         |                                                       4                  |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy                              |                               1                                   1  1   |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Sciatic, Degeneration                |                         1  1     1              2                 1      |             
                                           |__________________________________________________________________________|             
   Spinal Cord                             | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration                         |          1  1        1  1  1  1  1  1     1     2  1  1           1  1  1|             
      Meninges, Cyst Epithelial Inclusion  |                                                                   X      |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  57                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 _____________________________________________________________________________________________________________________              
                                           | 3| 1| 3| 1| 1| 1| 1| 1| 3| 1| 1| 1| 3| 3| 1| 3| 2| 3| 3| 3| 3| 3| 1| 1| 3|             
                             DAY ON TEST   | 7| 2| 7| 8| 8| 2| 2| 8| 1| 4| 8| 8| 7| 7| 8| 7| 0| 7| 7| 7| 7| 7| 8| 8| 7|             
                                           | 1| 3| 1| 5| 5| 8| 3| 3| 7| 6| 5| 3| 1| 1| 5| 1| 9| 1| 1| 1| 1| 1| 3| 5| 1|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    7000 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                         |                                                 1                        |             
                                           |__________________________________________________________________________|             
   Lung                                    | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                   3                                                      |             
      Hemorrhage                           |                                     1        2                           |             
      Thrombosis                           |                         1                                                |             
      Alveolar Epithelium, Hyperplasia     |                                                          1  1            |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation                         |                                              2  2                        |             
      Turbinate, Inflammation, Suppurative |                2                                                         |             
      Turbinate, Olfactory Epithelium,     |                                                                          |             
           Degeneration                    | 2     2  2  1  2  1  1  2  2  2  2  2  3  1  2  2  2  2  3  2  1  2  1  2|             
      Turbinate, Olfactory Epithelium,     |                                                                          |             
           Inflammation, Chronic           | 1     2  1              1     1  1  1  2     1  1  2  2  1  1  1     1  2|             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                              3                           |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |       2                 2                                                |             
                                           |__________________________________________________________________________|             
   Zymbal's Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Bilateral, Fibrosis, Focal           |                                     2                                    |             
      Bilateral, Fibrosis                  |                                                    2                     |             
      Bilateral, Hydronephrosis            |                                                                2         |             
      Bilateral, Nephropathy               |                2                                                         |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Suppurative            |                1                                                         |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                             Page  58                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 1| 1| 3| 1| 3| 3| 3| 3| 3|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 8| 2| 7| 2| 7| 7| 7| 7| 1|                             |            |
                                           | 3| 1| 1| 1| 1| 1| 3| 8| 1| 3| 1| 1| 1| 1| 7|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|                             |      A     |
    7000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  +  A  +  +  +  +  A                              |  33        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  37        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  36        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  A  +  +  +  +  A                              |  36        |
      Parasite                             |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  A  +  +  +  +  A                              |  36        |
      Parasite                             |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
      Angiectasis                          |                                                                          |      2  1.5|
      Basophilic Focus                     |                                                                          |      4  3.5|
      Clear Cell Focus                     |                                  1                                       |      1  1.0|
      Eosinophilic Focus                   |                                                                          |      3  2.0|
      Hematopoietic Cell Proliferation     |                                                                          |      1  1.0|
      Mixed Cell Focus                     |                                     2                                    |      3  2.0|
      Necrosis                             |                                                                          |      2  1.0|
      Vacuolization Cytoplasmic            |    1  3                          3                                       |     14  1.8|
      Bile Duct, Hyperplasia               |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                                  +                                       |   2        |
      Necrosis                             |                                  2                                       |      2  3.0|
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  59                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 1| 1| 3| 1| 3| 3| 3| 3| 3|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 8| 2| 7| 2| 7| 7| 7| 7| 1|                             |            |
                                           | 3| 1| 1| 1| 1| 1| 3| 8| 1| 3| 1| 1| 1| 1| 7|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|                             |      A     |
    7000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
      Angiectasis                          |       1                                                                  |      1  1.0|
      Focal Cellular Change                |                                     1                                    |      6  1.2|
      Inflammation, Chronic                |                                           2                              |      1  2.0|
      Duct, Cyst                           |                X                                                         |      1     |
                                           |__________________________________________________________________________|____________|
   Pharynx                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
      Epithelium, Hyperplasia              | 2        1     3  1     4                                                |     15  2.7|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  37        |
      Hyperplasia                          |          1                                                               |      4  1.5|
      Inflammation, Suppurative            |                                                                          |      2  1.5|
      Necrosis                             |                                                                          |      2  1.5|
                                           |__________________________________________________________________________|____________|
   Tongue                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
      Hyperplasia, Focal                   |                1                                                         |      1  1.0|
      Hyperplasia                          |       1                                                                  |      6  1.2|
      Hypertrophy, Focal                   |                                           1                              |      4  1.0|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  60                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 1| 1| 3| 1| 3| 3| 3| 3| 3|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 8| 2| 7| 2| 7| 7| 7| 7| 1|                             |            |
                                           | 3| 1| 1| 1| 1| 1| 3| 8| 1| 3| 1| 1| 1| 1| 7|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|                             |      A     |
    7000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
      Angiectasis                          |                                  1                                       |      1  1.0|
      Hyperplasia                          |    1  2  1                    1  2                                       |     13  1.2|
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  M  +  +  +  +  M                              |  34        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  M  +  +  +  A  +  +  M  +  M                              |  35        |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
      Cyst                                 |                               X                                          |      1     |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  39        |
      Hyperplasia                          |                                                                          |      1  4.0|
      Inflammation                         |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Penis                                   |                            A                                             |   2        |
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  37        |
      Angiectasis                          |                                     1                                    |      1  1.0|
      Atrophy                              |                                                                          |      1  4.0|
      Inflammation, Chronic                |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +                              |  37        |
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  39        |
      Atrophy                              | 3                 3  1                                                   |      8  2.0|
      Mineralization                       |                                  1                                       |      1  1.0|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  61                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 1| 1| 3| 1| 3| 3| 3| 3| 3|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 8| 2| 7| 2| 7| 7| 7| 7| 1|                             |            |
                                           | 3| 1| 1| 1| 1| 1| 3| 8| 1| 3| 1| 1| 1| 1| 7|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|                             |      A     |
    7000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
      Hyperplasia                          |                               2                                          |      4  2.3|
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  M  +  +  +  +  +  +  +  M  M  +  +  +  +                              |  32        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | M  M  M  +  M  +  +  +  +  A  M  +  M  +  M                              |  23        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  A  +  +  +  M  +                              |  37        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  +  M  +  M  +  +  M  A  +  M  M  +  +                              |  22        |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
      Hematopoietic Cell Proliferation     |          2                                                               |      4  2.0|
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  36        |
      Necrosis                             |                      1                                                   |      1  1.0|
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M                              |            |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  39        |
      Inflammation, Suppurative            |                                                                          |      1  1.0|
      Prepuce, Inflammation, Chronic       |                               4                                          |      2  4.0|
      Sebaceous Gland, Hyperplasia         |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
      Atrophy                              | 1                                                                        |      4  1.0|
 _____________________________________________________________________________________________________________________|            |
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                             Page  62                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 1| 1| 3| 1| 3| 3| 3| 3| 3|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 8| 2| 7| 2| 7| 7| 7| 7| 1|                             |            |
                                           | 3| 1| 1| 1| 1| 1| 3| 8| 1| 3| 1| 1| 1| 1| 7|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|                             |      A     |
    7000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
      Sciatic, Degeneration                |                                                                          |      5  1.2|
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
      Degeneration                         | 1  1  1        1  1     1     1  1                                       |     23  1.0|
      Meninges, Cyst Epithelial Inclusion  |                                                                          |      1     |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
      Inflammation                         |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
      Congestion                           |                                        2                                 |      2  2.5|
      Hemorrhage                           |                                                                          |      2  1.5|
      Thrombosis                           |                                                                          |      1  1.0|
      Alveolar Epithelium, Hyperplasia     |       4  4  4                    1  2                                    |      7  2.4|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
      Inflammation                         |                                                                          |      2  2.0|
      Turbinate, Inflammation, Suppurative |                                                                          |      1  2.0|
      Turbinate, Olfactory Epithelium,     |                                                                          |            |
           Degeneration                    | 2  2  3  2  2  2  2  2  2     2  2  2  2  2                              |     38  1.9|
      Turbinate, Olfactory Epithelium,     |                                                                          |            |
           Inflammation, Chronic           |    1  1  1  1  1  1  1  1     1  1  1  1  1                              |     30  1.2|
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  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  63                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-06                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:31:26    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 1| 1| 3| 1| 3| 3| 3| 3| 3|                             |            |
                             DAY ON TEST   | 8| 7| 7| 7| 7| 7| 8| 2| 7| 2| 7| 7| 7| 7| 1|                             |            |
                                           | 3| 1| 1| 1| 1| 1| 3| 8| 1| 3| 1| 1| 1| 1| 7|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      T     |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|                             |      A     |
    7000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|                             |      L     |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 SPECIAL SENSES SYSTEM - cont              |                                                                          |            |
      Inflammation, Chronic                |                                                                          |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
      Hyperplasia                          |                                                                          |      2  2.0|
                                           |__________________________________________________________________________|____________|
   Zymbal's Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
      Bilateral, Fibrosis, Focal           |                                                                          |      1  2.0|
      Bilateral, Fibrosis                  |                                                                          |      1  2.0|
      Bilateral, Hydronephrosis            |                                                                          |      1  2.0|
      Bilateral, Nephropathy               |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +                              |  38        |
      Inflammation, Suppurative            |                                                                          |      1  1.0|
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  64                                                               
                                                                                                                                   
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