TABLE 4.
Lesions after Intermittent Exposures to 1200 ppm Diacetyl
| 0 ppm | 1200 ppm | |
|---|---|---|
| Nasal lesions | ||
| Inflammation, chronic active | 0/5a | 5/5 (2.0)b |
| Exudate, suppurative | 0/5 | 2/5 (1.0) |
| Respiratory epithelium, necrosis, and ulceration | 0/5 | 3/5 (1.0) |
| Respiratory epithelium, degeneration, vacuolar | 0/5 | 4/5 (2.0) |
| Respiratory epithelium, metaplasia, squamous | 0/5 | 5/5 (2.6) |
| Olfactory epithelium, metaplasia, respiratory | 0/5 | 1/5 (2.0) |
| Olfactory epithelium, atrophy | 0/5 | 4/5 (2.0) |
| Total group score | 0c | 46 |
| Lung lesions | ||
| Peribronchial lymphocytic inflammation | 0/5 | 5/5 (2.6) |
| Peribronchiolar lymphocytic inflammation | 0/5 | 5/5 (1.6) |
| Total group score | 0 | 21 |
a
Number of animals with lesion/number evaluated.
b
Numbers in parentheses represent the average severity grades for those animals with the lesions. Severity grading scheme: minimal = 1, mild = 2, moderate = 3, marked = 4.
c
Total group scores were calculated by multiplying the number of animals with each lesion times the average severity grade for that lesion, and then adding the products obtained for each of these lesions.