Electron microscopic observations of influenzal pneumonitis.

Abstract

Summary: Influenzal pneumonia was experimentally induced in mice. The respiratory system during the acute phase was investigated by light and electron microscopy. Bronchial desquamation and necrosis were noted from the 2nd day to the 5th day and were most noticeable during the 3rd day. An electron dense degenerative substance was demonstrated in the degenerated epithelial cells on the 2nd and 3rd days. On the 3rd day, flattend basal cells appeared in the large bronchus. The basal cells were covered with one layer of cuboidal or flattened epithelial cells, both ciliated and non-ciliated.The epithelial cells had large nuclei and narrowly restricted cytoplasm. On the 5th day, stratified regenerating epithelial cells lined both the large and small bronchi. In the large bronchus, non-ciliated epithelial cells had cytoplasmic projections. Alveolar epithelial desquamation and necrosis, interstitial pneumonia and collapse of the lung were noted from the 2nd to the 5th day. On the 4th day, the collapse of the lung was most noticeable. No regenerative alveolar epithelium was demonstrated in these experiments.

Detection of RNA viruses in sudden infant death (SID)

“…The atypical peribronchiolar type of IP in one case could indicate an early stage of inflammation [22].…”

Reovirus infection in rat lungs as a model to study the pathogenesis of viral pneumonia

“…The kinetics of the pneumonia resembled those of other models in which pneumonia follows direct infection of lung epithelial cells. For example, in both the mouse model of influenza virus infection (22) and the cotton rat model for adenovirus infection (23), the pulmonary changes are also rapid, with severe pathology by day 3.…”