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TDMS Study 05135-05 Pathology Tables

NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09




       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: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 1| 3| 1| 3| 3| 3| 1| 3| 3| 3| 3| 1| 1| 3| 3| 1| 1| 3| 1| 3| 3| 3|             
                             DAY ON TEST   | 6| 6| 6| 8| 6| 8| 6| 6| 6| 8| 6| 6| 6| 6| 8| 8| 6| 6| 8| 8| 6| 8| 6| 6| 6|             
                                           | 8| 8| 8| 6| 8| 6| 8| 8| 8| 6| 8| 8| 8| 8| 6| 6| 8| 8| 6| 6| 8| 6| 8| 8| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fatty Change                         | 1                                                                        |             
      Fibrosis                             |                                                                          |             
      Fibrosis, Multifocal                 | 1                                                                        |             
      Hepatodiaphragmatic Nodule           |                            X                          X                  |             
      Inflammation                         |                                                                          |             
      Inflammation, Multifocal             | 2                                1                                       |             
      Necrosis, Multifocal                 |                                                                          |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                                  +                                       |             
      Necrosis                             |                                  X                                       |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Atrophy, Focal                       |                                                                1         |             
      Atrophy                              |                         1        1  1  1        1                 1     1|             
      Atrophy, Multifocal                  |       1                                                                  |             
      Infiltration Cellular, Focal, Mixed  |                                                                          |             
          Cell                             |                                        1                                 |             
      Infiltration Cellular, Mixed Cell    |                                     1              1                     |             
                                           |__________________________________________________________________________|             
   Pharynx                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page   2                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 1| 3| 1| 3| 3| 3| 1| 3| 3| 3| 3| 1| 1| 3| 3| 1| 1| 3| 1| 3| 3| 3|             
                             DAY ON TEST   | 6| 6| 6| 8| 6| 8| 6| 6| 6| 8| 6| 6| 6| 6| 8| 8| 6| 6| 8| 8| 6| 8| 6| 6| 6|             
                                           | 8| 8| 8| 6| 8| 6| 8| 8| 8| 6| 8| 8| 8| 8| 6| 6| 8| 8| 6| 6| 8| 6| 8| 8| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy, Focal                |    1                                   1                                 |             
      Cardiomyopathy                       |                                                                          |             
      Cardiomyopathy, Multifocal           |          2     2  1  1     1              2  1  1           1  1         |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Vacuolization Cytoplasmic, Focal     |                   1                                                      |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          | 1        1              1                       4           1        1   |             
      Pars Distalis, Cyst                  |                                                       X                  |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                            X                 X                           |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page   3                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 1| 3| 1| 3| 3| 3| 1| 3| 3| 3| 3| 1| 1| 3| 3| 1| 1| 3| 1| 3| 3| 3|             
                             DAY ON TEST   | 6| 6| 6| 8| 6| 8| 6| 6| 6| 8| 6| 6| 6| 6| 8| 8| 6| 6| 8| 8| 6| 8| 6| 6| 6|             
                                           | 8| 8| 8| 6| 8| 6| 8| 8| 8| 6| 8| 8| 8| 8| 6| 6| 8| 8| 6| 6| 8| 6| 8| 8| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS 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                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |    1                                                                     |             
      Hypospermia                          |                                                                          |             
      Inflammation, Chronic                |    1                                                                     |             
                                           |__________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                                                                          |             
      Infiltration Cellular, Mixed Cell    |                                                                          |             
      Inflammation, Suppurative            |                2                                                         |             
                                           |__________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Corpora Amylacea                     |                                                                X         |             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration                         |    1                                                                     |             
      Interstitial Cell, Hyperplasia       | 4  4  3     1     4  4  3        2  2  3        2  2        3        1   |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node                              |                      +                                                   |             
      Pancreatic, Congestion               |                      X                                                   |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | M  +  +  +  M  +  +  M  M  +  +  +  +  +  +  M  +  M  +  +  +  +  +  +  +|             
      Congestion                           |    X     X     X  X        X  X  X        X           X  X     X        X|             
      Hyperplasia                          |                                                          X               |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  M  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +|             
      Congestion                           |             X                                                            |             
      Hyperplasia                          |                         X  X        X           X  X        X     X      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  +  +  M  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|             
      Congestion                           | X  X     X     X     X  X  X        X     X  X     X  X  X              X|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page   4                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 1| 3| 1| 3| 3| 3| 1| 3| 3| 3| 3| 1| 1| 3| 3| 1| 1| 3| 1| 3| 3| 3|             
                             DAY ON TEST   | 6| 6| 6| 8| 6| 8| 6| 6| 6| 8| 6| 6| 6| 6| 8| 8| 6| 6| 8| 8| 6| 8| 6| 6| 6|             
                                           | 8| 8| 8| 6| 8| 6| 8| 8| 8| 6| 8| 8| 8| 8| 6| 6| 8| 8| 6| 6| 8| 6| 8| 8| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
      Hyperplasia                          |          X     X                                      X  X           X   |             
      Pigmentation, Hemosiderin            | X  X                       X                 X                          X|             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Accessory Spleen                     |                                                             X        X   |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  M  +  +  +  M  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  +  +  M  +  M|             
      Hyperplasia                          |                                                                1         |             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Spinal Cord                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infiltration Cellular, Mixed Cell    |                                                                          |             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                            X                                             |             
      Hemorrhage                           |       2                                                                  |             
      Hemorrhage, Multifocal               | 3  3     2  2  3  4  4  3  2  3  3  1  1  2  2  1  1  4  3  1  1  2  2  1|             
      Alveolar Epithelium, Hyperplasia     |                                                                          |             
      Alveolar Epithelium, Hyperplasia,    |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page   5                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 1| 3| 1| 3| 3| 3| 1| 3| 3| 3| 3| 1| 1| 3| 3| 1| 1| 3| 1| 3| 3| 3|             
                             DAY ON TEST   | 6| 6| 6| 8| 6| 8| 6| 6| 6| 8| 6| 6| 6| 6| 8| 8| 6| 6| 8| 8| 6| 8| 6| 6| 6|             
                                           | 8| 8| 8| 6| 8| 6| 8| 8| 8| 6| 8| 8| 8| 8| 6| 6| 8| 8| 6| 6| 8| 6| 8| 8| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
           Multifocal                      |       1                       2                                          |             
      Alveolus, Hemorrhage                 |       1                                                                  |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Focal, Histiocyte               |                            1                                             |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Multifocal, Histiocyte          |                                                    1     1               |             
      Peribronchial, Hyperplasia, Lymphoid,|                                                                          |             
           Multifocal                      |          1                 1                          1                  |             
      Perivascular, Hyperplasia, Focal,    |                                                                          |             
           Lymphoid                        |                2                                                         |             
      Perivascular, Hyperplasia, Lymphoid, |                                                                          |             
           Multifocal                      |          1                 1     1              1  1     1     1     1  1|             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Turbinate, Infiltration Cellular,    |                                                                          |             
           Mixed Cell                      |                                                                          |             
      Turbinate, Inflammation, Suppurative |                      1                                                   |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Harderian Gland                         |                   +     +                                      +         |             
      Hemorrhage                           |                         X                                                |             
      Hyperplasia, Lymphoid                |                   1                                            1         |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Bilateral, Nephropathy, Chronic      | 2  1        1     1  1  1     1  1     1        1  1        1        1  1|             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Calculus Micro Observation Only      | X                                   X                                    |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   6                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 3| 1| 3| 3| 3| 1| 3| 3| 3| 3| 3|                             |            |
                             DAY ON TEST   | 6| 6| 6| 6| 6| 8| 6| 6| 6| 8| 6| 6| 6| 6| 6|                             |            |
                                           | 8| 8| 8| 8| 8| 6| 8| 8| 8| 6| 8| 8| 8| 8| 8|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +                              |  39        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Fatty Change                         |                                                                          |      1  1.0|
      Fibrosis                             |                         1                                                |      1  1.0|
      Fibrosis, Multifocal                 |                                                                          |      1  1.0|
      Hepatodiaphragmatic Nodule           |       X        X     X                                                   |      5     |
      Inflammation                         |          1                                                               |      1  1.0|
      Inflammation, Multifocal             |                                                                          |      2  1.5|
      Necrosis, Multifocal                 |                         1                                                |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   1        |
      Necrosis                             |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Atrophy, Focal                       |                                                                          |      1  1.0|
      Atrophy                              |                                           1                              |      8  1.0|
      Atrophy, Multifocal                  |                                                                          |      1  1.0|
      Infiltration Cellular, Focal, Mixed  |                                                                          |            |
          Cell                             |                                                                          |      1  1.0|
      Infiltration Cellular, Mixed Cell    |                                                                          |      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   7                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 3| 1| 3| 3| 3| 1| 3| 3| 3| 3| 3|                             |            |
                             DAY ON TEST   | 6| 6| 6| 6| 6| 8| 6| 6| 6| 8| 6| 6| 6| 6| 6|                             |            |
                                           | 8| 8| 8| 8| 8| 6| 8| 8| 8| 6| 8| 8| 8| 8| 8|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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                  |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Pharynx                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Cardiomyopathy, Focal                |                                                                          |      2  1.0|
      Cardiomyopathy                       |                                        1                                 |      1  1.0|
      Cardiomyopathy, Multifocal           |       1     1           1  1                                             |     14  1.2|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Vacuolization Cytoplasmic, Focal     |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +                              |  38        |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hyperplasia                          |    1        1                       1     1                              |      4  1.0|
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hyperplasia                          |    2  1  4  3        1                                                   |     11  1.8|
      Pars Distalis, Cyst                  |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page   8                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 3| 1| 3| 3| 3| 1| 3| 3| 3| 3| 3|                             |            |
                             DAY ON TEST   | 6| 6| 6| 6| 6| 8| 6| 6| 6| 8| 6| 6| 6| 6| 6|                             |            |
                                           | 8| 8| 8| 8| 8| 6| 8| 8| 8| 6| 8| 8| 8| 8| 8|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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                                 |                                                                          |      2     |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hemorrhage                           |                                                                          |      1  1.0|
      Hypospermia                          |                                           4                              |      1  4.0|
      Inflammation, Chronic                |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +                              |  39        |
      Hyperplasia                          |                         4                                                |      1  4.0|
      Infiltration Cellular, Mixed Cell    |                   1                       1                              |      2  1.0|
      Inflammation, Suppurative            |                                  1        1                              |      3  1.3|
                                           |__________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Corpora Amylacea                     |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Degeneration                         |                                                                          |      1  1.0|
      Interstitial Cell, Hyperplasia       | 1     4  1  2        2  1  1  2  2  4  1  3                              |     26  2.4|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |                                                                          |   1        |
      Pancreatic, Congestion               |                                                                          |      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   9                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 3| 1| 3| 3| 3| 1| 3| 3| 3| 3| 3|                             |            |
                             DAY ON TEST   | 6| 6| 6| 6| 6| 8| 6| 6| 6| 8| 6| 6| 6| 6| 6|                             |            |
                                           | 8| 8| 8| 8| 8| 6| 8| 8| 8| 6| 8| 8| 8| 8| 8|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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, Bronchial                   | +  M  +  +  M  +  +  +  +  +  +  +  +  +  +                              |  32        |
      Congestion                           |                X     X  X  X  X                                          |     17     |
      Hyperplasia                          |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  M  +  +  +  +  +  M  +                              |  35        |
      Congestion                           |                                                                          |      1     |
      Hyperplasia                          | X                                                                        |      8     |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  +  M  +  +  +  +  +  M  +  +  +  +  +                              |  35        |
      Congestion                           |             X  X              X  X     X  X                              |     20     |
      Hyperplasia                          |                                                                          |      5     |
      Pigmentation, Hemosiderin            |                               X                                          |      6     |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Accessory Spleen                     |                                                                          |      2     |
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  M  +  M  +  +  +  +  +  +  +  +  +                              |  35        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M                              |   3        |
      Hyperplasia                          |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  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  10                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 3| 1| 3| 3| 3| 1| 3| 3| 3| 3| 3|                             |            |
                             DAY ON TEST   | 6| 6| 6| 6| 6| 8| 6| 6| 6| 8| 6| 6| 6| 6| 6|                             |            |
                                           | 8| 8| 8| 8| 8| 6| 8| 8| 8| 6| 8| 8| 8| 8| 8|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 NERVOUS SYSTEM - cont                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  39        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Infiltration Cellular, Mixed Cell    |                   1                                                      |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Congestion                           |                                                                          |      1     |
      Hemorrhage                           | 1  1                                   1  2                              |      5  1.4|
      Hemorrhage, Multifocal               |       1  2  1  1  1  2  1  3  2  1  2                                    |     35  2.0|
      Alveolar Epithelium, Hyperplasia     |                         1     1  1                                       |      3  1.0|
      Alveolar Epithelium, Hyperplasia,    |                                                                          |            |
           Multifocal                      |                                                                          |      2  1.5|
      Alveolus, Hemorrhage                 |                               1                                          |      2  1.0|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Focal, Histiocyte               |                                     1                                    |      2  1.0|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Multifocal, Histiocyte          |                                                                          |      2  1.0|
      Peribronchial, Hyperplasia, Lymphoid,|                                                                          |            |
           Multifocal                      |                1           1                                             |      5  1.0|
      Perivascular, Hyperplasia, Focal,    |                                                                          |            |
           Lymphoid                        |                                                                          |      1  2.0|
      Perivascular, Hyperplasia, Lymphoid, |                                                                          |            |
           Multifocal                      | 1  1        1  1                    1  1                                 |     15  1.0|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Turbinate, Infiltration Cellular,    |                                                                          |            |
           Mixed Cell                      |          2                                                               |      1  2.0|
      Turbinate, 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  11                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 3| 1| 3| 3| 3| 1| 3| 3| 3| 3| 3|                             |            |
                             DAY ON TEST   | 6| 6| 6| 6| 6| 8| 6| 6| 6| 8| 6| 6| 6| 6| 6|                             |            |
                                           | 8| 8| 8| 8| 8| 6| 8| 8| 8| 6| 8| 8| 8| 8| 8|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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 - cont                 |                                                                          |            |
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         |                +              +                                          |   5        |
      Hemorrhage                           |                                                                          |      1     |
      Hyperplasia, Lymphoid                |                1              1                                          |      4  1.0|
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Bilateral, Nephropathy, Chronic      |    1  1  1           1  1        1  2  2  2                              |     23  1.2|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Calculus Micro Observation Only      |                                                                          |      2     |
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  12                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 1| 3| 1| 3| 3| 3| 3| 3| 3| 3| 1| 3| 1| 3| 3| 1| 3| 1| 3| 1| 1| 3| 3|             
                             DAY ON TEST   | 6| 6| 8| 6| 8| 6| 6| 6| 6| 6| 6| 6| 8| 6| 8| 6| 6| 8| 6| 8| 6| 8| 8| 6| 6|             
                                           | 8| 8| 6| 8| 6| 8| 8| 8| 8| 8| 8| 8| 6| 8| 6| 8| 8| 6| 8| 6| 8| 6| 6| 8| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS 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                               |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Liver                                   |       +     +  +                    +  +  +        +  +  +     +  +  +   |             
      Hepatodiaphragmatic Nodule           |       X        X                       X              X           X  X   |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                                                             +        +   |             
      Necrosis                             |                                                             X        X   |             
                                           |__________________________________________________________________________|             
   Pancreas                                |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Pharynx                                 |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      |       +     +                       +     +        +     +     +  +      |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Heart                                   |       +     +                       +     +        +     +     +  +      |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  13                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 1| 3| 1| 3| 3| 3| 3| 3| 3| 3| 1| 3| 1| 3| 3| 1| 3| 1| 3| 1| 1| 3| 3|             
                             DAY ON TEST   | 6| 6| 8| 6| 8| 6| 6| 6| 6| 6| 6| 6| 8| 6| 8| 6| 6| 8| 6| 8| 6| 8| 8| 6| 6|             
                                           | 8| 8| 6| 8| 6| 8| 8| 8| 8| 8| 8| 8| 6| 8| 6| 8| 8| 6| 8| 6| 8| 6| 6| 8| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         |       +     +           +  +     +  +     +        +     +  +  +  +  +  +|             
      Hyperplasia                          |                                                             2            |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           |       +     +                       +     +        +     +     +  +      |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Preputial Gland                         |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Prostate                                |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Interstitial Cell, Hyperplasia       | 1  4     1     1  4  2  4  1  1  2     2     2  2     4     1  1     1  1|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Lymph Node                              |                                                                +         |             
      Pancreatic, Congestion               |                                                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   |       +     +                       +     +        +     +     +  +      |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  14                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 1| 3| 1| 3| 3| 3| 3| 3| 3| 3| 1| 3| 1| 3| 3| 1| 3| 1| 3| 1| 1| 3| 3|             
                             DAY ON TEST   | 6| 6| 8| 6| 8| 6| 6| 6| 6| 6| 6| 6| 8| 6| 8| 6| 6| 8| 6| 8| 6| 8| 8| 6| 6|             
                                           | 8| 8| 6| 8| 6| 8| 8| 8| 8| 8| 8| 8| 6| 8| 6| 8| 8| 6| 8| 6| 8| 6| 6| 8| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 |       +     +        +  +           +     +        +     +  +  +  +      |             
      Congestion                           |                      X                                      X  X         |             
      Hyperplasia                          |                      X  X                                   X            |             
                                           |__________________________________________________________________________|             
   Spleen                                  |       +     +           +     +     +     +     +  +     +     +  +      |             
      Accessory Spleen                     |                         X                                                |             
                                           |__________________________________________________________________________|             
   Thymus                                  |       +     +                       +     +        +     +     +  +      |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Skin                                    |       +     +                       +     +        +     +     +  +      |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    |       +     +                       +     +        +     +     +  +      |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   |       +     +           +           +     +        +     +     +  +      |             
      Hemorrhage                           |                         2                                                |             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Spinal Cord                             |       +     +                       +     +        +     +     +  +      |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  15                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 1| 3| 1| 3| 3| 3| 3| 3| 3| 3| 1| 3| 1| 3| 3| 1| 3| 1| 3| 1| 1| 3| 3|             
                             DAY ON TEST   | 6| 6| 8| 6| 8| 6| 6| 6| 6| 6| 6| 6| 8| 6| 8| 6| 6| 8| 6| 8| 6| 8| 8| 6| 6|             
                                           | 8| 8| 6| 8| 6| 8| 8| 8| 8| 8| 8| 8| 6| 8| 6| 8| 8| 6| 8| 6| 8| 6| 6| 8| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS 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|             
 __________________________________________|__________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
      Hemorrhage                           |       2     1                       2     1        1     1     2  1      |             
      Hemorrhage, Multifocal               | 1  1     1     1  1  1  1  1  2  1     1     1  1     1     1        1  1|             
      Alveolar Epithelium, Hyperplasia,    |                                                                          |             
           Multifocal                      |                      1  2                    2  2     1     3            |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Multifocal, Histiocyte          |          1           1  1                    2  2     2     3            |             
      Peribronchial, Hyperplasia, Focal,   |                                                                          |             
           Lymphoid                        |                                        1     1                           |             
      Peribronchial, Hyperplasia, Lymphoid,|                                                                          |             
           Multifocal                      |          1                                      1           1            |             
      Perivascular, Hyperplasia, Focal,    |                                                                          |             
           Lymphoid                        |       1                                                                  |             
      Perivascular, Hyperplasia, Lymphoid, |                                                                          |             
           Multifocal                      |          1           1  2              1     3  3     2     3           1|             
                                           |__________________________________________________________________________|             
   Nose                                    |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Trachea                                 |       +     +                       +     +        +     +     +  +      |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     |       +     +                       +     +        +     +     +  +      |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  |       +     +                       +     +        +     +     +  +      |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         |       +     +                       +     +        +     +     +  +      |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  16                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3|                             |            |
                             DAY ON TEST   | 8| 6| 6| 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 6|                             |            |
                                           | 6| 8| 8| 8| 8| 8| 6| 8| 8| 8| 8| 8| 8| 8| 8|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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                               | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +                 +                       +                              |  15        |
      Hepatodiaphragmatic Nodule           | X                 X                       X                              |      9     |
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   2        |
      Necrosis                             |                                                                          |      2     |
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Pharynx                                 | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +                 +                                                      |  10        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            | +                 +                                                      |  10        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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  17                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3|                             |            |
                             DAY ON TEST   | 8| 6| 6| 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 6|                             |            |
                                           | 6| 8| 8| 8| 8| 8| 6| 8| 8| 8| 8| 8| 8| 8| 8|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 CARDIOVASCULAR SYSTEM - cont              |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +                 +                                                      |  10        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +              +           +                                          |  18        |
      Hyperplasia                          |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +                 +                                                      |  10        |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Prostate                                | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Interstitial Cell, Hyperplasia       |    1  3  2  1  4     1  2  2  1  1  4  3  1                              |     31  2.0|
 _____________________________________________________________________________________________________________________|            |
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                             Page  18                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3|                             |            |
                             DAY ON TEST   | 8| 6| 6| 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 6|                             |            |
                                           | 6| 8| 8| 8| 8| 8| 6| 8| 8| 8| 8| 8| 8| 8| 8|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |                   +                                                      |   2        |
      Pancreatic, Congestion               |                   X                                                      |      1     |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +                 +           +           +                              |  15        |
      Congestion                           |                                                                          |      3     |
      Hyperplasia                          |                                           X                              |      4     |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +                 +                                                      |  13        |
      Accessory Spleen                     |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +                 +                                                      |  10        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +                 +                                                      |  10        |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +                 +                                                      |  10        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +                 +                                                      |  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  19                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3|                             |            |
                             DAY ON TEST   | 8| 6| 6| 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 6|                             |            |
                                           | 6| 8| 8| 8| 8| 8| 6| 8| 8| 8| 8| 8| 8| 8| 8|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 NERVOUS SYSTEM - cont                     |                                                                          |            |
      Hemorrhage                           |                                                                          |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             | +                 +                                                      |  10        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hemorrhage                           | 1                 2                                                      |     10  1.4|
      Hemorrhage, Multifocal               |    1  1  1  1  1     1  1  2  1  1  1  1  2                              |     30  1.1|
      Alveolar Epithelium, Hyperplasia,    |                                                                          |            |
           Multifocal                      |    3  3  2  3           1     3  3     1  1                              |     15  2.1|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Multifocal, Histiocyte          |    3  3  3  3           1  1  3  3     1  1                              |     17  2.0|
      Peribronchial, Hyperplasia, Focal,   |                                                                          |            |
           Lymphoid                        |                                                                          |      2  1.0|
      Peribronchial, Hyperplasia, Lymphoid,|                                                                          |            |
           Multifocal                      |    1  1                       1  1        1                              |      8  1.0|
      Perivascular, Hyperplasia, Focal,    |                                                                          |            |
           Lymphoid                        |                                                                          |      1  1.0|
      Perivascular, Hyperplasia, Lymphoid, |                                                                          |            |
           Multifocal                      | 1  3  3  3  3  1     1  1  1  3  3  1  1  3                              |     23  2.0|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +                 +                                                      |  10        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +                 +                                                      |  10        |
 _____________________________________________________________________________________________________________________|            |
                                                                                                                                    
  * : 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: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3|                             |            |
                             DAY ON TEST   | 8| 6| 6| 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 6|                             |            |
                                           | 6| 8| 8| 8| 8| 8| 6| 8| 8| 8| 8| 8| 8| 8| 8|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +                 +                                                      |  10        |
                                           |__________________________________________________________________________|____________|
   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  21                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 1| 3| 3| 3| 1| 1| 3| 3| 1| 1| 3| 1| 3| 3| 1| 3| 1| 3| 3| 1| 3| 3|             
                             DAY ON TEST   | 6| 6| 6| 8| 6| 6| 6| 8| 8| 6| 6| 8| 8| 6| 6| 6| 6| 8| 6| 8| 6| 6| 8| 6| 6|             
                                           | 7| 7| 7| 6| 7| 7| 7| 6| 6| 7| 7| 6| 6| 7| 3| 7| 7| 6| 7| 6| 7| 7| 6| 7| 7|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 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                               |          +           +  +        +  +     +        +     +        +      |             
                                           |__________________________________________________________________________|             
   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                                   |          +        +  +  +        +  +  +  +  +  +  +     +  +  +  +      |             
      Clear Cell Focus                     |                                                                          |             
      Fatty Change                         |                   1                          1                           |             
      Fatty Change, Multifocal             |                                                                2         |             
      Fibrosis, Multifocal                 |                                                                          |             
      Hepatodiaphragmatic Nodule           |                                        X        X           X            |             
      Necrosis, Focal                      |                                                                          |             
      Necrosis, Multifocal                 |                                                                          |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                                     +     +                              |             
      Congestion                           |                                           X                              |             
                                           |__________________________________________________________________________|             
   Pancreas                                |          +           +  +        +  +     +        +     +        +      |             
                                           |__________________________________________________________________________|             
   Pharynx                                 |          +           +  +        +  +     +        +     +        +      |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         |          +           +  +        +  +     +        +     +        +      |             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    |          +           +  +        +  +     A        +     +        +      |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      |          +           +  +        +  +     A        +     +        +      |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  22                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 1| 3| 3| 3| 1| 1| 3| 3| 1| 1| 3| 1| 3| 3| 1| 3| 1| 3| 3| 1| 3| 3|             
                             DAY ON TEST   | 6| 6| 6| 8| 6| 6| 6| 8| 8| 6| 6| 8| 8| 6| 6| 6| 6| 8| 6| 8| 6| 6| 8| 6| 6|             
                                           | 7| 7| 7| 6| 7| 7| 7| 6| 6| 7| 7| 6| 6| 7| 3| 7| 7| 6| 7| 6| 7| 7| 6| 7| 7|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 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 - cont              |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            |          +           +  +        +  +     +        +     +        +      |             
                                           |__________________________________________________________________________|             
   Heart                                   |          +           +  +        +  +     +        +     +        +      |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          |          +           +  +        +  +     +        +     +        +      |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         |       +  +           +  +        +  +     +        +     +        +      |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      |          +           +  +        +  +     +        +     +        +      |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       |          +           +  +        +  +     M        +     +        +      |             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         |          +           +  +        +  +  +  +  +     +     +        +      |             
      Pars Distalis, Cyst                  |                                                                          |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           |          +           +  +        +  +     A        +     +        +      |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              |          +           +  +        +  +     +        +     +        +      |             
                                           |__________________________________________________________________________|             
   Preputial Gland                         |          +           +  +        +  +     M        +     +        +      |             
                                           |__________________________________________________________________________|             
   Prostate                                |          +           +  +        +  +     +        +     +        +      |             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         |          +           +  +        +  +     +        +     +        +      |             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Degeneration                         |                                                                         4|             
      Granuloma                            |                                                                         X|             
      Inflammation                         |                                                                         4|             
      Interstitial Cell, Hyperplasia       | 1  1  2     2  3  2        4  2  1     1     1  3     1     3  2  1  4   |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  23                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 1| 3| 3| 3| 1| 1| 3| 3| 1| 1| 3| 1| 3| 3| 1| 3| 1| 3| 3| 1| 3| 3|             
                             DAY ON TEST   | 6| 6| 6| 8| 6| 6| 6| 8| 8| 6| 6| 8| 8| 6| 6| 6| 6| 8| 6| 8| 6| 6| 8| 6| 6|             
                                           | 7| 7| 7| 6| 7| 7| 7| 6| 6| 7| 7| 6| 6| 7| 3| 7| 7| 6| 7| 6| 7| 7| 6| 7| 7|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 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                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             |          +           +  +        +  +     M        +     +        +      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   |          +           +  +        +  +     +        +     +        +      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  |          +           +  +     +  +  +     +        +     +        +      |             
      Hyperplasia                          |                               X                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  |          +           +  +        +  +     +        +     +        +      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 |          +           +  +        +  +     +        +     +        +      |             
      Congestion                           |                                                                          |             
      Hyperplasia                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Spleen                                  |          +           +  +        +  +     +  +     +     +        +      |             
      Accessory Spleen                     |                                              X                           |             
                                           |__________________________________________________________________________|             
   Thymus                                  |          +           +  +        +  +     +        +     +        +      |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           |          +           +  +        +  +     M        +     +        +      |             
                                           |__________________________________________________________________________|             
   Skin                                    |          +           +  +        +  +     M        +     +        +     +|             
      Subcutaneous Tissue, Hemorrhage      |                                     X                                    |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    |          +  +        +  +        +  +     M        +     +        +      |             
                                           |__________________________________________________________________________|             
   Skeletal Muscle                         |                                           +                              |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   |          +           +  +        +  +     +        +     +        +      |             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        |          +           +  +        +  +     M        +     +        +      |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  24                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 1| 3| 3| 3| 1| 1| 3| 3| 1| 1| 3| 1| 3| 3| 1| 3| 1| 3| 3| 1| 3| 3|             
                             DAY ON TEST   | 6| 6| 6| 8| 6| 6| 6| 8| 8| 6| 6| 8| 8| 6| 6| 6| 6| 8| 6| 8| 6| 6| 8| 6| 6|             
                                           | 7| 7| 7| 6| 7| 7| 7| 6| 6| 7| 7| 6| 6| 7| 3| 7| 7| 6| 7| 6| 7| 7| 6| 7| 7|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 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                     |                                                                          |             
   Spinal Cord                             |          +           +  +        +  +     M        +     +        +      |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  |          +           +  +        +  +     A        +     +        +      |             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |                                           2                              |             
      Fibrosis, Multifocal                 |    1                                                                     |             
      Hemorrhage                           |          2           2  2        2  2              3     2        2      |             
      Hemorrhage, Multifocal               | 1  1  1     1  1  1        1  1        1     1        1     1  1     1  1|             
      Alveolar Epithelium, Hyperplasia,    |                                                                          |             
           Multifocal                      |    2        1  2           2  2                 1     1        2     2   |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Focal, Histiocyte               |                   1                                                      |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Multifocal, Histiocyte          |    2  1     1  2           2  2              1  2     1     1  2     2   |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Histiocyte                      |                                  1                                       |             
      Peribronchial, Hyperplasia, Focal,   |                                                                          |             
           Lymphoid                        |                                                             1            |             
      Peribronchial, Hyperplasia, Lymphoid,|                                                                          |             
           Multifocal                      |    1           2           2  2                 1              2     1   |             
      Perivascular, Hyperplasia, Lymphoid, |                                                                          |             
           Multifocal                      |    2  1     1  3     1     2  2     1        1  2     1     1  3     3  1|             
                                           |__________________________________________________________________________|             
   Nose                                    |          +           +  +        +  +     +        +     +        +      |             
      Turbinate, Hemorrhage                |                                           X                              |             
                                           |__________________________________________________________________________|             
   Trachea                                 |          +           +  +        +  +     A        +     +        +      |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     |          +           +  +        +  +     +        +     +        +      |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  |       +  +           +  +        +  +     +        +     +        +      |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  25                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 1| 3| 3| 3| 1| 1| 3| 3| 1| 1| 3| 1| 3| 3| 1| 3| 1| 3| 3| 1| 3| 3|             
                             DAY ON TEST   | 6| 6| 6| 8| 6| 6| 6| 8| 8| 6| 6| 8| 8| 6| 6| 6| 6| 8| 6| 8| 6| 6| 8| 6| 6|             
                                           | 7| 7| 7| 6| 7| 7| 7| 6| 6| 7| 7| 6| 6| 7| 3| 7| 7| 6| 7| 6| 7| 7| 6| 7| 7|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 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|             
 __________________________________________|__________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
      Bilateral, Nephropathy, Chronic      |       1                                                                  |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         |          +  +        +  +        +  +  +  A        +     +        +      |             
      Calculus Micro Observation Only      |             X                          X                                 |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  26                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3|                             |            |
                             DAY ON TEST   | 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 8| 6| 6| 6|                             |            |
                                           | 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  |          +                       +                                       |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 |          +                       +                                       |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  |          +                       +                                       |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               |          +                       +                                       |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                |          +                       +                                       |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  |          +                       +                                       |  10        |
                                           |__________________________________________________________________________|____________|
   Liver                                   |          +           +  +  +     +  +  +                                 |  22        |
      Clear Cell Focus                     |                                        1                                 |      1  1.0|
      Fatty Change                         |                         1                                                |      3  1.0|
      Fatty Change, Multifocal             |                            1                                             |      2  1.5|
      Fibrosis, Multifocal                 |                            1                                             |      1  1.0|
      Hepatodiaphragmatic Nodule           |          X              X  X        X  X                                 |      8     |
      Necrosis, Focal                      |                      1                                                   |      1  1.0|
      Necrosis, Multifocal                 |                         1  1                                             |      2  1.0|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   2        |
      Congestion                           |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Pancreas                                |          +                       +                                       |  11        |
                                           |__________________________________________________________________________|____________|
   Pharynx                                 |          +                       +                                       |  11        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         |          +                       +                                       |  11        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    |          +                       +                                       |  10        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3|                             |            |
                             DAY ON TEST   | 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 8| 6| 6| 6|                             |            |
                                           | 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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                  |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      |          +                       +                                       |  10        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            |          +                       +                                       |  11        |
                                           |__________________________________________________________________________|____________|
   Heart                                   |          +                       +                                       |  11        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          |          +                       +                                       |  11        |
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         |          +                       +                                       |  12        |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      |          +                       +                                       |  11        |
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       |          +                       +                                       |  10        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         |          +                       +        +                              |  14        |
      Pars Distalis, Cyst                  |                                           X                              |      1     |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           |          +                       +                                       |  10        |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              |          +                       +     +                                 |  12        |
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         |          +                       +                                       |  10        |
                                           |__________________________________________________________________________|____________|
   Prostate                                |          +                       +                                       |  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: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3|                             |            |
                             DAY ON TEST   | 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 8| 6| 6| 6|                             |            |
                                           | 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         |          +                       +                                       |  11        |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Degeneration                         |                                                                          |      1  4.0|
      Granuloma                            |                                                                          |      1     |
      Inflammation                         |                                                                          |      1  4.0|
      Interstitial Cell, Hyperplasia       | 1  2  2     1  3  3  4  4  4  1  1  1  2  2                              |     31  2.1|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             |          +                       +                                       |  10        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   |          +                       +                                       |  11        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  |          +                       +                                       |  12        |
      Hyperplasia                          |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  |          +                       +                                       |  11        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 |          +              +        +                                       |  12        |
      Congestion                           |                                  X                                       |      1     |
      Hyperplasia                          |                         X                                                |      1     |
                                           |__________________________________________________________________________|____________|
   Spleen                                  |          +                       +                                       |  12        |
      Accessory Spleen                     |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Thymus                                  |          +                       +                                       |  11        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           |          +                       +                                       |  10        |
                                           |__________________________________________________________________________|____________|
   Skin                                    |          +                       +                                       |  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  29                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3|                             |            |
                             DAY ON TEST   | 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 8| 6| 6| 6|                             |            |
                                           | 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 INTEGUMENTARY SYSTEM - cont               |                                                                          |            |
      Subcutaneous Tissue, Hemorrhage      |                                                                          |      1     |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    |          +                       +                                       |  11        |
                                           |__________________________________________________________________________|____________|
   Skeletal Muscle                         |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   |          +                       +                                       |  11        |
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        |          +                       +                                       |  10        |
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             |          +                       +                                       |  10        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  |          +                       +                                       |  10        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Congestion                           |                                                                          |      1  2.0|
      Fibrosis, Multifocal                 |                                                                          |      1  1.0|
      Hemorrhage                           |          2     1                 3                                       |     11  2.1|
      Hemorrhage, Multifocal               | 1  1  1     1     1     2  3  1     1  1  1                              |     26  1.1|
      Alveolar Epithelium, Hyperplasia,    |                                                                          |            |
           Multifocal                      |    1        1                 3     3                                    |     13  1.8|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Focal, Histiocyte               |                                                                          |      1  1.0|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Multifocal, Histiocyte          |    1        1  2        1     3     3                                    |     18  1.7|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Histiocyte                      |                                                                          |      1  1.0|
      Peribronchial, Hyperplasia, Focal,   |                                                                          |            |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3|                             |            |
                             DAY ON TEST   | 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 8| 6| 6| 6|                             |            |
                                           | 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
           Lymphoid                        |                         2     1                                          |      3  1.3|
      Peribronchial, Hyperplasia, Lymphoid,|                                                                          |            |
           Multifocal                      |                                                                          |      7  1.6|
      Perivascular, Hyperplasia, Lymphoid, |                                                                          |            |
           Multifocal                      | 1  1  1     1  2  1     2  1  3     3                                    |     25  1.6|
                                           |__________________________________________________________________________|____________|
   Nose                                    |          +                       +                                       |  11        |
      Turbinate, Hemorrhage                |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Trachea                                 |          +                       +                                       |  10        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     |          +                       +                                       |  11        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  |          +                       +                                       |  12        |
      Bilateral, Nephropathy, Chronic      |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         |          +     +                 +                                       |  13        |
      Calculus Micro Observation Only      |                X                                                         |      3     |
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  31                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 1| 3| 3| 1| 3| 3| 3| 3| 1| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3|             
                             DAY ON TEST   | 6| 8| 6| 6| 8| 6| 6| 6| 6| 8| 6| 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 8| 6| 6|             
                                           | 7| 6| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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                               |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Liver                                   |    +     +  +  +        +  +              +                       +     +|             
      Fatty Change                         |          1     1        1                                               1|             
      Fatty Change, Multifocal             |                                                                          |             
      Hepatodiaphragmatic Nodule           |    X        X  X           X                                             |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                                                                          |             
      Necrosis                             |                                                                          |             
                                           |__________________________________________________________________________|             
   Pancreas                                |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Pharynx                                 |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      |    +        +              +              +                       +      |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Heart                                   |    +        +              +              +                       +      |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  32                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 1| 3| 3| 1| 3| 3| 3| 3| 1| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3|             
                             DAY ON TEST   | 6| 8| 6| 6| 8| 6| 6| 6| 6| 8| 6| 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 8| 6| 6|             
                                           | 7| 6| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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|             
 __________________________________________|__________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         |    +        +              +              +     +     +           +      |             
      Hemorrhage, Focal                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           |    +        +              +              +                       +      |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Preputial Gland                         |    +        +              +              +                       +      |             
      Infiltration Cellular, Mixed Cell    |                                                                          |             
      Inflammation, Suppurative            |                                                                          |             
                                           |__________________________________________________________________________|             
   Prostate                                |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Interstitial Cell, Hyperplasia       | 4     2  3     4  4  2  3     1  2  2  4     4  2  1  3  2  4  1     4  3|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  33                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 1| 3| 3| 1| 3| 3| 3| 3| 1| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3|             
                             DAY ON TEST   | 6| 8| 6| 6| 8| 6| 6| 6| 6| 8| 6| 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 8| 6| 6|             
                                           | 7| 6| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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|             
 __________________________________________|__________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
   Lymph Node, Mandibular                  |    +        +              +              +                       +      |             
      Congestion                           |                                           X                              |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 |    +        +              +           +  +                       +      |             
      Hyperplasia                          |                                        X                                 |             
                                           |__________________________________________________________________________|             
   Spleen                                  |    +        +              +              +        +              +      |             
      Accessory Spleen                     |                                                    X                     |             
      Capsule, Hyperplasia, Lymphoid       |                                                                          |             
                                           |__________________________________________________________________________|             
   Thymus                                  |    +        +              +              +                       +      |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           |    +        +              +        +     +                       +      |             
                                           |__________________________________________________________________________|             
   Skin                                    |    +        +              +        +     +                       +      |             
      Inflammation, Chronic                |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    |    +        +              +              +                       +      |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Spinal Cord                             |    +        +              +              +                       +      |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  34                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 1| 3| 3| 1| 3| 3| 3| 3| 1| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3|             
                             DAY ON TEST   | 6| 8| 6| 6| 8| 6| 6| 6| 6| 8| 6| 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 8| 6| 6|             
                                           | 7| 6| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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|             
 __________________________________________|__________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
      Hemorrhage                           |    2        2              2              3                       1      |             
      Hemorrhage, Multifocal               | 1     2  1     1  1     1        1  1           1  1     1  1  1     1  1|             
      Alveolar Epithelium, Hyperplasia     |                                                                          |             
      Alveolar Epithelium, Hyperplasia,    |                                                                          |             
           Multifocal                      | 2        2     1                 1                          2        1  2|             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Focal, Histiocyte               |                                              1                           |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Multifocal, Histiocyte          | 2        2     1  1              1     1        1           2        1  2|             
      Peribronchial, Hyperplasia, Lymphoid,|                                                                          |             
           Multifocal                      | 1        1                                                           1   |             
      Perivascular, Hyperplasia, Focal,    |                                                                          |             
           Lymphoid                        |       1                 2                                                |             
      Perivascular, Hyperplasia, Lymphoid, |                                                                          |             
           Multifocal                      | 3        2     1                 2     1     1  1     1     2        2  2|             
                                           |__________________________________________________________________________|             
   Nose                                    |    +        +              +              +                       +      |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +        +              +              +                       +      |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     |    +        +              +              +                       +      |             
      Cataract                             |                                                                          |             
      Retina, Degeneration                 |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  |    +        +     +        +              +                       +      |             
      Nephropathy, Chronic                 |                   1                                                      |             
      Bilateral, Cyst                      |                   X                                                      |             
      Bilateral, Nephropathy, Chronic      |                                                                          |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         |    +        +              +              +                       +      |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  35                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 1| 1| 3| 3| 3| 3| 3| 3| 1| 3| 1| 3| 1|                             |            |
                             DAY ON TEST   | 6| 6| 8| 8| 6| 6| 6| 6| 6| 6| 8| 6| 8| 6| 8|                             |            |
                                           | 7| 7| 6| 6| 7| 7| 7| 7| 7| 7| 6| 7| 6| 7| 6|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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                               |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Liver                                   |       +  +                 +  +     +     +                              |  15        |
      Fatty Change                         |                                                                          |      4  1.0|
      Fatty Change, Multifocal             |                            2                                             |      1  2.0|
      Hepatodiaphragmatic Nodule           |                                                                          |      4     |
                                           |__________________________________________________________________________|____________|
   Mesentery                               | +                             +                                          |   2        |
      Necrosis                             | X                             X                                          |      2     |
                                           |__________________________________________________________________________|____________|
   Pancreas                                |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Pharynx                                 |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      |       +  +                    +     +     +                              |  10        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR 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  36                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 1| 1| 3| 3| 3| 3| 3| 3| 1| 3| 1| 3| 1|                             |            |
                             DAY ON TEST   | 6| 6| 8| 8| 6| 6| 6| 6| 6| 6| 8| 6| 8| 6| 8|                             |            |
                                           | 7| 7| 6| 6| 7| 7| 7| 7| 7| 7| 6| 7| 6| 7| 6|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 CARDIOVASCULAR SYSTEM - cont              |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Heart                                   |       +  +                    +     +     +                              |  10        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         |       +  +                 +  +  +  +     +                              |  14        |
      Hemorrhage, Focal                    |                            2                                             |      1  2.0|
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           |       +  +                    +     +     +                              |  10        |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +     +  +           +        +     +     +                              |  12        |
      Infiltration Cellular, Mixed Cell    | 2                    4                                                   |      2  3.0|
      Inflammation, Suppurative            | 4                    4                                                   |      2  4.0|
                                           |__________________________________________________________________________|____________|
   Prostate                                |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         |       +  +                    +     +     +                              |  10        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 1| 1| 3| 3| 3| 3| 3| 3| 1| 3| 1| 3| 1|                             |            |
                             DAY ON TEST   | 6| 6| 8| 8| 6| 6| 6| 6| 6| 6| 8| 6| 8| 6| 8|                             |            |
                                           | 7| 7| 6| 6| 7| 7| 7| 7| 7| 7| 6| 7| 6| 7| 6|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 GENITAL SYSTEM - cont                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Interstitial Cell, Hyperplasia       | 3  1     1  4  4  4  2  3  2     2     3                                 |     31  2.7|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  |       +  +                 +  +     +     +                              |  11        |
      Congestion                           |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 |       +  +                    +     +     +                              |  11        |
      Hyperplasia                          |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Spleen                                  |    +  +  +                 +  +     +     +                              |  13        |
      Accessory Spleen                     |                            X                                             |      2     |
      Capsule, Hyperplasia, Lymphoid       |    X                                                                     |      1     |
                                           |__________________________________________________________________________|____________|
   Thymus                                  |       +  +                    +     +     +                              |  10        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           |       +  +                    +     +     +                              |  11        |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +     +  +                    +     +     +                              |  12        |
      Inflammation, Chronic                | X                                                                        |      1     |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    |       +  +                    +     +     +                              |  10        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : 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: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 1| 1| 3| 3| 3| 3| 3| 3| 1| 3| 1| 3| 1|                             |            |
                             DAY ON TEST   | 6| 6| 8| 8| 6| 6| 6| 6| 6| 6| 8| 6| 8| 6| 8|                             |            |
                                           | 7| 7| 6| 6| 7| 7| 7| 7| 7| 7| 6| 7| 6| 7| 6|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             |       +  +                    +     +     +                              |  10        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hemorrhage                           |       2  2                    3     2     2                              |     10  2.1|
      Hemorrhage, Multifocal               | 1           1  1  1  1  2  1     1     1                                 |     24  1.1|
      Alveolar Epithelium, Hyperplasia     |                      2                                                   |      1  2.0|
      Alveolar Epithelium, Hyperplasia,    |                                                                          |            |
           Multifocal                      |             1  1                 2     2                                 |     11  1.5|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Focal, Histiocyte               |                                                                          |      1  1.0|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Multifocal, Histiocyte          | 1           1  1     2           2     2                                 |     16  1.4|
      Peribronchial, Hyperplasia, Lymphoid,|                                                                          |            |
           Multifocal                      | 1                    1           1     1                                 |      7  1.0|
      Perivascular, Hyperplasia, Focal,    |                                                                          |            |
           Lymphoid                        |                                                                          |      2  1.5|
      Perivascular, Hyperplasia, Lymphoid, |                                                                          |            |
           Multifocal                      | 2     1     1  1     3  1  1     2     2                                 |     20  1.6|
                                           |__________________________________________________________________________|____________|
   Nose                                    |       +  +                    +     +     +                              |  10        |
                                           |__________________________________________________________________________|____________|
   Trachea                                 |       +  +                    +     +     +                              |  11        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES 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  39                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 1| 1| 3| 3| 3| 3| 3| 3| 1| 3| 1| 3| 1|                             |            |
                             DAY ON TEST   | 6| 6| 8| 8| 6| 6| 6| 6| 6| 6| 8| 6| 8| 6| 8|                             |            |
                                           | 7| 7| 6| 6| 7| 7| 7| 7| 7| 7| 6| 7| 6| 7| 6|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 SPECIAL SENSES SYSTEM - cont              |                                                                          |            |
   Eye                                     |    +  +  +                    +     +     +                              |  11        |
      Cataract                             |    X                                                                     |      1     |
      Retina, Degeneration                 |    4                                                                     |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  |       +  +              +     +     +     +                              |  12        |
      Nephropathy, Chronic                 |                                                                          |      1  1.0|
      Bilateral, Cyst                      |                                                                          |      1     |
      Bilateral, Nephropathy, Chronic      |                         1                                                |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         |       +  +                    +     +     +                              |  10        |
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
  * : 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: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3| 1| 1| 3| 3| 1|             
                             DAY ON TEST   | 6| 6| 6| 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 8| 6| 6| 8| 8| 6| 6| 8|             
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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                               |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Liver                                   |       +     +     +     +  +     +        +        +        +  +        +|             
      Fatty Change, Focal                  |                                  1                                       |             
      Fibrosis, Focal                      |       1                                                                  |             
      Fibrosis                             |                         1                                                |             
      Hepatodiaphragmatic Nodule           |             X           X  X              X                 X            |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                                     +                    +               |             
      Necrosis                             |                                     X                    X               |             
                                           |__________________________________________________________________________|             
   Pancreas                                |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Pharynx                                 |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Salivary Glands                         |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      |                   +                                +        +  +        +|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  41                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3| 1| 1| 3| 3| 1|             
                             DAY ON TEST   | 6| 6| 6| 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 8| 6| 6| 8| 8| 6| 6| 8|             
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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|             
 __________________________________________|__________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM - cont              |                                                                          |             
   Heart                                   |                   +                                +        +  +        +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         |             +  +  +                       +        +        +  +        +|             
      Hyperplasia                          |             4                                                            |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           |                   +                                +        +  +        +|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              |                   +                                +        +  +  +     +|             
                                           |__________________________________________________________________________|             
   Preputial Gland                         |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Prostate                                |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Interstitial Cell, Hyperplasia       | 3  1  4  1  3  2     2  2  1  3  2  3  3  2  2  3     4  1        2  1   |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   |                   +                       +        +        +  +        +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  42                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3| 1| 1| 3| 3| 1|             
                             DAY ON TEST   | 6| 6| 6| 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 8| 6| 6| 8| 8| 6| 6| 8|             
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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|             
 __________________________________________|__________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
      Hyperplasia                          |                                           X                              |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 |                   +                                +        +  +        +|             
      Congestion                           |                                                    X                     |             
                                           |__________________________________________________________________________|             
   Spleen                                  |                   +                       +     +  +        +  +        +|             
      Accessory Spleen                     |                                           X     X                        |             
                                           |__________________________________________________________________________|             
   Thymus                                  |                   +                                +        +  +        +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Skin                                    |                   +                                +        +  +        +|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    |                   +                                +        +  +        +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Spinal Cord                             |                   +                                +        +  +        +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |                   2                                1        2  1        2|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  43                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 1| 3| 3| 1| 1| 3| 3| 1|             
                             DAY ON TEST   | 6| 6| 6| 6| 6| 6| 8| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 8| 6| 6| 8| 8| 6| 6| 8|             
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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                 |                                                                          |             
      Hemorrhage, Multifocal               | 1  2     1  2        1  1        1  1  2  1  2  1        1        1  1   |             
      Alveolar Epithelium, Hyperplasia,    |                                                                          |             
           Focal                           |                                                                          |             
      Alveolar Epithelium, Hyperplasia,    |                                                                          |             
           Multifocal                      | 1  2                       2        2     1     2                        |             
      Alveolus, Hemorrhage                 |                                                                          |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Focal, Histiocyte               |                                                                          |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Multifocal, Histiocyte          | 1  2                 1  1  2        2     2     2                 1      |             
      Peribronchial, Hyperplasia, Lymphoid,|                                                                          |             
           Multifocal                      | 1                          2        1     2                              |             
      Perivascular, Hyperplasia, Focal,    |                                                                          |             
           Lymphoid                        |                         1                                         1      |             
      Perivascular, Hyperplasia, Lymphoid, |                                                                          |             
           Multifocal                      | 2  1                 1     3     1  3     2     2        1               |             
                                           |__________________________________________________________________________|             
   Nose                                    |                   +                                +        +  +        +|             
                                           |__________________________________________________________________________|             
   Trachea                                 |                   +                                +        +  +        +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     |                   +                                +        +  +  +     +|             
      Cataract                             |                                                                   X      |             
      Retina, Degeneration                 |                                                                   4      |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  |    +        +     +        +                       +  +     +  +        +|             
      Bilateral, Nephropathy, Chronic      |    1        1              2                          1                  |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         |                   +                    +        +  +     +  +  +  +  +  +|             
      Calculus Micro Observation Only      |                                        X        X                 X  X   |             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  44                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 1| 1| 3| 1| 3| 1| 3| 3| 3| 1| 3|                             |            |
                             DAY ON TEST   | 6| 6| 6| 6| 8| 8| 6| 8| 6| 8| 6| 6| 6| 8| 6|                             |            |
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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                               |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Liver                                   |             +  +     +     +     +     +                                 |  17        |
      Fatty Change, Focal                  |                                                                          |      1  1.0|
      Fibrosis, Focal                      |                                                                          |      1  1.0|
      Fibrosis                             |                                                                          |      1  1.0|
      Hepatodiaphragmatic Nodule           |             X                    X     X                                 |      8     |
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   2        |
      Necrosis                             |                                                                          |      2     |
                                           |__________________________________________________________________________|____________|
   Pancreas                                |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Pharynx                                 |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      |             +  +     +     +           +                                 |  10        |
 _____________________________________________________________________________________________________________________|            |
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                                                                                                    
                                                             Page  45                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 1| 1| 3| 1| 3| 1| 3| 3| 3| 1| 3|                             |            |
                             DAY ON TEST   | 6| 6| 6| 6| 8| 8| 6| 8| 6| 8| 6| 6| 6| 8| 6|                             |            |
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Heart                                   |             +  +     +     +           +                                 |  10        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         |             +  +  +  +     +           +                                 |  14        |
      Hyperplasia                          |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           |             +  +     +     +           +                                 |  10        |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              |             +  +     +     +           +                                 |  11        |
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Prostate                                |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +     +  +  +  +  +  +  +  +                              |  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  46                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 1| 1| 3| 1| 3| 1| 3| 3| 3| 1| 3|                             |            |
                             DAY ON TEST   | 6| 6| 6| 6| 8| 8| 6| 8| 6| 8| 6| 6| 6| 8| 6|                             |            |
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 GENITAL SYSTEM - cont                     |                                                                          |            |
      Interstitial Cell, Hyperplasia       | 1  2  4  2     1     1  3     2  1  1  1  2                              |     32  2.1|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   |             +  +     +     +           +                                 |  11        |
      Hyperplasia                          |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 |             +  +     +     +           +                                 |  10        |
      Congestion                           |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Spleen                                  |             +  +     +     +     +     +                                 |  13        |
      Accessory Spleen                     |                                  X                                       |      3     |
                                           |__________________________________________________________________________|____________|
   Thymus                                  |             +  +     +     +           +                                 |  10        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Skin                                    |             +  +     +     +           +                                 |  10        |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    |             +  +     +     +           +                                 |  10        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   |             +  +     +     +           +                                 |  10        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  47                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 1| 1| 3| 1| 3| 1| 3| 3| 3| 1| 3|                             |            |
                             DAY ON TEST   | 6| 6| 6| 6| 8| 8| 6| 8| 6| 8| 6| 6| 6| 8| 6|                             |            |
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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                        |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             |             +  +     +     +           +                                 |  10        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hemorrhage                           |             2  2     2     2           2                                 |     10  1.8|
      Hemorrhage, Multifocal               | 1     2           1     1     1     1     1                              |     22  1.2|
      Alveolar Epithelium, Hyperplasia,    |                                                                          |            |
           Focal                           |                                           2                              |      1  2.0|
      Alveolar Epithelium, Hyperplasia,    |                                                                          |            |
           Multifocal                      | 1     2                 1        2  2                                    |     11  1.6|
      Alveolus, Hemorrhage                 |                                     1                                    |      1  1.0|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Focal, Histiocyte               |                                           2                              |      1  2.0|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Multifocal, Histiocyte          | 1  1  2                 2        2  1                                    |     15  1.5|
      Peribronchial, Hyperplasia, Lymphoid,|                                                                          |            |
           Multifocal                      |                                                                          |      4  1.5|
      Perivascular, Hyperplasia, Focal,    |                                                                          |            |
           Lymphoid                        |                                                                          |      2  1.0|
      Perivascular, Hyperplasia, Lymphoid, |                                                                          |            |
           Multifocal                      |       3     1        1  2  1     2  3     1                              |     17  1.8|
                                           |__________________________________________________________________________|____________|
   Nose                                    |             +  +     +     +           +                                 |  10        |
                                           |__________________________________________________________________________|____________|
   Trachea                                 |             +  +     +     +           +                                 |  10        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES 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  48                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 3| 3| 3| 3| 1| 1| 3| 1| 3| 1| 3| 3| 3| 1| 3|                             |            |
                             DAY ON TEST   | 6| 6| 6| 6| 8| 8| 6| 8| 6| 8| 6| 6| 6| 8| 6|                             |            |
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 SPECIAL SENSES SYSTEM - cont              |                                                                          |            |
   Eye                                     |             +  +     +     +           +                                 |  11        |
      Cataract                             |                                                                          |      1     |
      Retina, Degeneration                 |                                                                          |      1  4.0|
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  |             +  +  +  +  +  +           +                                 |  16        |
      Bilateral, Nephropathy, Chronic      |                   1     1                                                |      6  1.2|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +        +  +  +     +     +           +                                 |  17        |
      Calculus Micro Observation Only      |          X                                                               |      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  49                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 1| 1| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 1| 3| 3| 3| 3| 3| 1| 3| 3| 1| 3| 3|             
                             DAY ON TEST   | 6| 8| 8| 6| 6| 6| 6| 6| 6| 8| 6| 6| 6| 8| 6| 6| 6| 6| 6| 8| 6| 6| 8| 6| 6|             
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage, Multifocal               |                                                                         1|             
      Inflammation, Multifocal, Suppurative|                                                                         1|             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia, Lymphoid                |                                                                          |             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrosis                             |                                                                          |             
      Fibrosis, Multifocal                 |                   1                                                      |             
      Hepatodiaphragmatic Nodule           |                      X        X                                X         |             
      Inflammation, Focal                  |                                                                          |             
      Necrosis, Focal                      | 1                                                                        |             
      Necrosis, Multifocal                 |                                  2                                       |             
      Sinusoid, Congestion, Focal          |    1                                                                     |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                                                                   +      |             
      Accessory Spleen                     |                                                                   X      |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Accessory Spleen                     |                                                                   X      |             
      Atrophy                              |                         1                 1        1  1        1        1|             
      Atrophy, Multifocal                  |                      1                                                   |             
      Infiltration Cellular, Mixed Cell    |       1                                                  1               |             
                                           |__________________________________________________________________________|             
   Pharynx                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  50                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 1| 1| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 1| 3| 3| 3| 3| 3| 1| 3| 3| 1| 3| 3|             
                             DAY ON TEST   | 6| 8| 8| 6| 6| 6| 6| 6| 6| 8| 6| 6| 6| 8| 6| 6| 6| 6| 6| 8| 6| 6| 8| 6| 6|             
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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                  |                                                                          |             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infiltration Cellular, Mixed Cell    |                                                                          |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cardiomyopathy                       |                1  1     1  1                    1  1     1     1     1   |             
      Cardiomyopathy, Multifocal           |       1  1                                                               |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          |                         1                          1                     |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hyperplasia                          | 1        1           1  2        1           2  1                    1   |             
      Pars Distalis, Cyst                  |                   X                    X                                 |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cyst                                 |                            X     X                                       |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  51                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 1| 1| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 1| 3| 3| 3| 3| 3| 1| 3| 3| 1| 3| 3|             
                             DAY ON TEST   | 6| 8| 8| 6| 6| 6| 6| 6| 6| 8| 6| 6| 6| 8| 6| 6| 6| 6| 6| 8| 6| 6| 8| 6| 6|             
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Inflammation, Chronic                |                                           4                              |             
                                           |__________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infiltration Cellular, Mixed Cell    |                                           1                              |             
                                           |__________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Corpora Amylacea                     |    X  X                                                                  |             
      Inflammation, Suppurative            |                                                             1        1   |             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Interstitial Cell, Hyperplasia       | 4  4  2  4  4  1  4  1  2  1  3  2  2  3  1  1  4  2  2  1  4  3  2  2  2|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |    X  X  X  X  X           X     X     X  X  X           X  X     X      |             
      Hyperplasia                          |                                                 X                       X|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Congestion                           |    X  X        X                                                         |             
      Hyperplasia                          |          X                                                              X|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  M  M  M  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  M  +  +  +  +  +|             
      Congestion                           | X              X           X  X        X  X  X  X  X  X     X     X     X|             
      Hyperplasia                          |                               X     X           X                    X  X|             
      Pigmentation, Hemosiderin            |                                                       X                 X|             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Accessory Spleen                     |                                  X                                       |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  M  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  52                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 1| 1| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 1| 3| 3| 3| 3| 3| 1| 3| 3| 1| 3| 3|             
                             DAY ON TEST   | 6| 8| 8| 6| 6| 6| 6| 6| 6| 8| 6| 6| 6| 8| 6| 6| 6| 6| 6| 8| 6| 6| 8| 6| 6|             
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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|             
 __________________________________________|__________________________________________________________________________|             
 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|             
      Hyperplasia                          | 1                                                                        |             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Spinal Cord                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infiltration Cellular, Mixed Cell    |          1                                1                    1         |             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemorrhage                           |             2  2                                2                 2  1   |             
      Hemorrhage, Multifocal               | 2  3  2  1        1  1  1  2  1  2  1  2  1  2     2  1  2  1  1        1|             
      Alveolar Epithelium, Hyperplasia,    |                                                                          |             
           Focal                           | 1                                                              2         |             
      Alveolar Epithelium, Hyperplasia     |                                                                          |             
      Alveolar Epithelium, Hyperplasia,    |                                                                          |             
           Multifocal                      |                               1                                         1|             
      Alveolus, Hemorrhage                 | 1                                                                    1   |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Focal, Histiocyte               | 1                                                                        |             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Multifocal, Histiocyte          |                1  1  1  1     1     1     1  1  1  1  1                 2|             
      Alveolus, Infiltration Cellular,     |                                                                          |             
           Histiocyte                      |                                                                1         |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                             Page  53                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 _____________________________________________________________________________________________________________________              
                                           | 3| 1| 1| 3| 3| 3| 3| 3| 3| 1| 3| 3| 3| 1| 3| 3| 3| 3| 3| 1| 3| 3| 1| 3| 3|             
                             DAY ON TEST   | 6| 8| 8| 6| 6| 6| 6| 6| 6| 8| 6| 6| 6| 8| 6| 6| 6| 6| 6| 8| 6| 6| 8| 6| 6|             
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 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                 |                                                                          |             
      Alveolus, Inflammation, Granulomatous|                                     1                                    |             
      Peribronchial, Hyperplasia, Focal,   |                                                                          |             
           Lymphoid                        |    1                                         1                    1      |             
      Peribronchial, Hyperplasia, Lymphoid |                                                          1               |             
      Peribronchial, Hyperplasia, Lymphoid,|                                                                          |             
           Multifocal                      |                                                                          |             
      Perivascular, Hyperplasia, Focal,    |                                                                          |             
           Lymphoid                        |                            2                                         1   |             
      Perivascular, Hyperplasia, Lymphoid, |                                                                          |             
           Multifocal                      | 1        1  1     1  1  1     2           1  1  1  2  1     1           1|             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Turbinate, Infiltration Cellular,    |                                                                          |             
           Multifocal, Mixed Cell          |                                                    1                     |             
      Turbinate, Infiltration Cellular,    |                                                                          |             
           Mixed Cell                      |                                                                          |             
      Turbinate, Inflammation, Suppurative |                                                                          |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Infiltration Cellular, Mononuclear   |                                                                          |             
          Cell, Multifocal                 |                                        1                                 |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Harderian Gland                         |             +                                      +           +         |             
      Hyperplasia, Lymphoid                |             1                                      1           1         |             
      Hyperplasia, Lymphoid, Multifocal    |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Bilateral, Nephropathy, Chronic      | 1        2  1  1  1  1  1     1  2  1     2  1  1  1  1     1  1     1   |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Calculus Micro Observation Only      |          X     X  X     X           X     X        X           X        X|             
 __________________________________________|__________________________________________________________________________              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  54                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 1| 1| 3| 3| 3| 3| 3| 3| 3| 1|                             |            |
                             DAY ON TEST   | 8| 6| 6| 6| 6| 8| 8| 6| 6| 6| 6| 6| 6| 6| 8|                             |            |
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hemorrhage, Multifocal               |                                                                          |      1  1.0|
      Inflammation, Multifocal, Suppurative|                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hyperplasia, Lymphoid                |    1                                                                     |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Fibrosis                             |                         1                                                |      1  1.0|
      Fibrosis, Multifocal                 |                                                                          |      1  1.0|
      Hepatodiaphragmatic Nodule           |          X                    X        X                                 |      6     |
      Inflammation, Focal                  |                1                                                         |      1  1.0|
      Necrosis, Focal                      |                                                                          |      1  1.0|
      Necrosis, Multifocal                 |                            1     1                                       |      3  1.3|
      Sinusoid, Congestion, Focal          |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   1        |
      Accessory Spleen                     |                                                                          |      1     |
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Accessory Spleen                     |                                                                          |      1     |
      Atrophy                              |                      1     1              1                              |      9  1.0|
      Atrophy, Multifocal                  |                                                                          |      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  55                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 1| 1| 3| 3| 3| 3| 3| 3| 3| 1|                             |            |
                             DAY ON TEST   | 8| 6| 6| 6| 6| 8| 8| 6| 6| 6| 6| 6| 6| 6| 8|                             |            |
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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                  |                                                                          |            |
      Infiltration Cellular, Mixed Cell    |                                                                          |      2  1.0|
                                           |__________________________________________________________________________|____________|
   Pharynx                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Infiltration Cellular, Mixed Cell    | 1                                                                        |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Blood Vessel                            | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Cardiomyopathy                       | 1                             1  1                                       |     12  1.0|
      Cardiomyopathy, Multifocal           |                                                                          |      2  1.0|
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hyperplasia                          |       1     1              1           1                                 |      6  1.0|
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hyperplasia                          |          2  2           1                                                |     11  1.4|
      Pars Distalis, Cyst                  |                                                                          |      2     |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  56                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 1| 1| 3| 3| 3| 3| 3| 3| 3| 1|                             |            |
                             DAY ON TEST   | 8| 6| 6| 6| 6| 8| 8| 6| 6| 6| 6| 6| 6| 6| 8|                             |            |
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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                   |                                                                          |            |
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Cyst                                 |          X                                                               |      3     |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Inflammation, Chronic                |                                                                          |      1  4.0|
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Infiltration Cellular, Mixed Cell    |                                                                          |      1  1.0|
                                           |__________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Corpora Amylacea                     |                                                                          |      2     |
      Inflammation, Suppurative            |                                                                          |      2  1.0|
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Interstitial Cell, Hyperplasia       | 1  2  3  4  2  1  1  4  2  3  2  4  4  4  2                              |     40  2.5|
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  +  +  M  +  +  +  M  +  +  +  +  +  +  +                              |  37        |
      Congestion                           | X     X        X           X  X     X                                    |     19     |
      Hyperplasia                          |    X        X           X              X                                 |      6     |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Congestion                           |                                                                          |      3     |
      Hyperplasia                          |             X        X           X                                       |      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  57                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 1| 1| 3| 3| 3| 3| 3| 3| 3| 1|                             |            |
                             DAY ON TEST   | 8| 6| 6| 6| 6| 8| 8| 6| 6| 6| 6| 6| 6| 6| 8|                             |            |
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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 - cont               |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  M  +  +  M  +  +  +  M  M  +  +  +  +                              |  30        |
      Congestion                           | X                 X     X                 X                              |     17     |
      Hyperplasia                          |             X           X              X                                 |      8     |
      Pigmentation, Hemosiderin            |                                                                          |      2     |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Accessory Spleen                     |                      X                                                   |      2     |
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  M  +  +  +  +  +  M  +  +  +  +  +  +  +                              |  36        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  +  M  M  M  M  M  M  M  M                              |   3        |
      Hyperplasia                          |                   2                                                      |      2  1.5|
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Spinal Cord                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
  * : Total animals with tissue examined microscopically; total animals with lesion and mean severity grade                         
  + : Tissue examined microscopically                M : Missing tissue                        1-4 : Lesion qualified as:           
  X : Lesion present but not qualified               A : Autolysis precludes examination               1) Minimal  3) Moderate      
  I : Insufficient tissue                        BLANK : Not examined                                  2) Mild     4) Marked        
                                                                                                                                    
                                                             Page  58                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 1| 1| 3| 3| 3| 3| 3| 3| 3| 1|                             |            |
                             DAY ON TEST   | 8| 6| 6| 6| 6| 8| 8| 6| 6| 6| 6| 6| 6| 6| 8|                             |            |
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Infiltration Cellular, Mixed Cell    |                                                                          |      3  1.0|
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Hemorrhage                           |                                                                          |      5  1.8|
      Hemorrhage, Multifocal               | 1  1  3  2  1  3  2  1  2  1  2  1  1  1  3                              |     35  1.6|
      Alveolar Epithelium, Hyperplasia,    |                                                                          |            |
           Focal                           |                                                                          |      2  1.5|
      Alveolar Epithelium, Hyperplasia     |                   2                                                      |      1  2.0|
      Alveolar Epithelium, Hyperplasia,    |                                                                          |            |
           Multifocal                      |                                        2                                 |      3  1.3|
      Alveolus, Hemorrhage                 |                   1                                                      |      3  1.0|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Focal, Histiocyte               |                                                                          |      1  1.0|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Multifocal, Histiocyte          |    1        1              1     1  1  2                                 |     18  1.1|
      Alveolus, Infiltration Cellular,     |                                                                          |            |
           Histiocyte                      |                   2                                                      |      2  1.5|
      Alveolus, Inflammation, Granulomatous|                                                                          |      1  1.0|
      Peribronchial, Hyperplasia, Focal,   |                                                                          |            |
           Lymphoid                        | 1                                                                        |      4  1.0|
      Peribronchial, Hyperplasia, Lymphoid |                                                                          |      1  1.0|
      Peribronchial, Hyperplasia, Lymphoid,|                                                                          |            |
           Multifocal                      |                                        1                                 |      1  1.0|
      Perivascular, Hyperplasia, Focal,    |                                                                          |            |
           Lymphoid                        |                                                                          |      2  1.5|
      Perivascular, Hyperplasia, Lymphoid, |                                                                          |            |
           Multifocal                      |    1  1     1        1  1  1     1  2  2                                 |     23  1.2|
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Turbinate, Infiltration Cellular,    |                                                                          |            |
           Multifocal, Mixed Cell          |                                                                          |      1  1.0|
      Turbinate, Infiltration Cellular,    |                                                                          |            |
           Mixed Cell                      |                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  59                                                               
                                                                                                                                   
NTP Experiment-Test: 05135-05                  NONNEOPLASTIC LESIONS BY INDIVIDUAL ANIMAL                         Report: PEIRPT09  
Study Type: SIX MONTH EXPOS.                                     ISOPRENE                                         Date: 10/15/04    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:16:09    
 __________________________________________________________________________________________________________________________________ 
                                           | 1| 3| 3| 3| 3| 1| 1| 3| 3| 3| 3| 3| 3| 3| 1|                             |            |
                             DAY ON TEST   | 8| 6| 6| 6| 6| 8| 8| 6| 6| 6| 6| 6| 6| 6| 8|                             |            |
                                           | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|                             |            |
 __________________________________________|__________________________________________________________________________|      T (*) |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      O     |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|                             |      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|                             |            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
      Turbinate, Inflammation, Suppurative |             3                                                            |      1  3.0|
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Infiltration Cellular, Mononuclear   |                                                                          |            |
          Cell, Multifocal                 |                                                                          |      1  1.0|
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         |                +                    +     +                              |   6        |
      Hyperplasia, Lymphoid                |                                                                          |      3  1.0|
      Hyperplasia, Lymphoid, Multifocal    |                2                    2     2                              |      3  2.0|
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Bilateral, Nephropathy, Chronic      |    1  1  1  2        2  1  1  2  1  1  1                                 |     29  1.2|
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +                              |  40        |
      Calculus Micro Observation Only      |    X  X                             X                                    |     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        
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
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