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Ultrastructural effects of N‐methyl‐N‐nitrosourea on the tracheobronchial epithelium of the Syrian Golden hamster
Author(s) -
Harris Curtis C.,
Kaufman David G.,
Sporn Michael B.,
Smith Joseph M.,
Jackson Frank,
Saffiotti Umberto
Publication year - 1973
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910120127
Subject(s) - squamous metaplasia , pathology , epithelium , squamous carcinoma , stratified squamous epithelium , ultrastructure , hamster , biology , respiratory epithelium , metaplasia , microbiology and biotechnology , carcinoma , medicine
Ten intratracheal instillations of N‐methyl‐N‐nitrosourea (NMU) caused squamous metaplastic and neoplastic changes in the tracheobronchial epithelium. Abnormal squamous metaplastic cells contained enlarged nuclei deeply indented by cytoplasmic invaginations, pleomorphic nucleoli, filamentous granules and many cytoplasmic fibrils. Prior to the appearance of tumors, autoradiograms revealed cells preparing for division, first in basal and then in all layers of the abnormal squamous metaplastic epithelium. Defects in the basement lamina were found in squamous metaplastic lesions. The ultrastructural changes in the tracheobronchial epithelium were similar to those described in hamsters exposed to benzo[a]pyrene‐ferric oxide as well as to those described in smoking dogs and in human bronchogenic carcinoma. The squamous metaplastic changes induced by NMU were clearly distinguishable from squamous metaplasia found in vitamin‐A deficiency.