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Table 4 Incidence and integrity of the histopathological findings of the lung and mediastinal lymph nodes 13 weeks after 90-day inhalation exposure to CWAAP-A

From: Dose–response relationship of pulmonary disorders by inhalation exposure to cross-linked water-soluble acrylic acid polymers in F344 rats

 

Male

Female

Exposure concentration (mg/m3)

0

0.3

1

3

10

0

0.3

1

3

10

No. of animals examined

8

8

8

8

8

8

8

8

8

8

13w recovery

          

Histopathological findings

          

 Mediastinal lymph node

          

  Lymphoid hyperplasia

0

0

0

0

0

0

0

0

0

0

 Lung

          

  Deposition of test compound (AB-positive material)

0

3

8***

8***

8***

0

3

8***

8***

8***

  

<1>

<1>

<1>

<2>

 

<1>

<1>

<1>

<2>

  Granulomatous change, alveolar

0

0

8***

8***

8***

0

0

8***

8***

8***

   

<1>

<1>

<1>

  

<1>

<1>

<1.3>

  Multifocal lesion, alveolar

          

   Hypertrophy/proliferation of alveolar epithelium

0

0

0

6**

8***

0

0

0

7***

8***

    

<1>

<1.8>

   

<1.1>

<1.8>

   Inflammation, air space

0

0

0

8***

8***

0

0

0

8***

8***

    

<1>

<1>

   

<1.1>

<1>

   Cholesterol creft, air space

0

0

0

1

8***

0

0

0

4*

8***

    

<1>

<1>

   

<1>

<1.1>

   Alveolitis

0

0

0

6**

8***

0

0

0

6**

8***

    

<1>

<2>

   

<1.2>

<1.8>

   Fibrous thickening, interstitial

0

0

0

6**

8***

0

0

0

6**

8***

    

<1>

<1>

   

<1>

<1.5>

  Accumulation of lipoproteinous material, air space

0

0

0

0

8***

0

0

0

0

7***

     

<1>

    

<1.4>

  1. Values indicate number of animals bearing lesions
  2. The value in angle bracket indicate the average of severity grade index of the lesion. The average of severity grade is calculated with a following equation
  3. Σ(grade X number of animals with grade)/number of affected animals
  4. Grade: 1, slight; 2, moderate; 3, marked; 4, severe. Significant difference: *, p < 0.05; **, p < 0.01; ***, p < 0.001 by Chi square test compared with each cont