Virus activation by vitamin A and NO2 gas exposures in hamsters.

Hamsters exposed to 10 ppm NO2 for 5 hr once a week for 4 weeks while undergoing acute vitamin A deficiency showed much reduced epithelial cell regeneration in the terminal bronchioles. Quantitative analysis done by autoradiography and scintillation counting from lung tissues indicates much reduced cell kinetics occurring in terminal bronchiolar alveolar region. Alveolar necrosis was often observed and no type II cell reversion occurred. Virus particles were found within the alveolar epithelial plasma membrane.