Showing papers by "Michael B. Sporn published in 1971"

Acute ultrastructural effects of benzo[a]pyrene and ferric oxide the hamster tracheobronchial epithelium.

Abstract: Summary The pathogenesis of epithelial hyperplasia and squamous metaplasia of the tracheobronchial epithelium, induced by polynuclear hydrocarbons, was studied, with the Syrian golden hamster as a suitable animal model. The acute cellular changes in the tracheobronchial epithelium, produced by intratracheal instillations of benzo[ a ]pyrene carried by ferric oxide particles, included focal replacement of the columnar cells with pleomorphic cells. These had the ultrastructural features of atypical squamous cells, i.e. , cytoplasmic filaments, widened intercellular spaces, abnormal desmosomes, and increased number of lysosomal derivatives. Polylobulated nuclei and pleomorphic nucleoli were prominent findings after multiple instillations of benzo[ a ]pyrene:ferric oxide. Intratracheal instillations of ferric oxide alone or pyrene:ferric oxide produced basal cell hyperplasia, which was reversible. The atypical squamous cells induced by benzo[ a ]pyrene:ferric oxide had ultrastructural features similar to hyperplastic epithelial cells described in the bronchi of smoking dogs and neoplastic squamous cells described in human bronchogenic carcinoma. This investigation is one of a series of studies to clarify the histogenesis of squamous cell carcinoma of the lung.

Isolation of Enzymatically Active Nuclei from Epithelial Cells of the Trachea

Abstract: Summary A simple method for the isolation of nuclei from tracheal epithelial cells is described. The isolated nuclei are morphologically well preserved and can be suspended in reproducible aliquots. RNA polymerase and exoribonuclease activity can be measured in the isolated nuclei.