Ultrastructural characteristics of carcinogen-induced dysplastic changes in tracheal epithelium
Squamous metaplasias with various degrees of atypia, carcinomas in situ, and microinvasive carcinomas produced in rat tracheal transplants by a 4-week exposure to dimethylbenz(a)anthracene were studied 12 to 96 weeks after cessation of carcinogen exposure. In addition to the classical nuclear and cytoplasmic indicators of atypism, the squamous metaplasias with slight and moderate atypia were characterized by the presence of glycogen in the spinous layer, atypical composite keratohyalin granules in the granular layer, and in most cases an orthokeratinized horny layer. The squamous metaplasias with severe atypia showed an increased secretory activity and a decreased number of desmosomes. Carcinomas in situ were characterized by numerous intracellular and extracellular microcysts filled with secretory material identified by histochemical techniques as containing neutral glycoproteins and sialomucins. Microinvasive carcinoma showed similar characteristics, with an increase in polylobulated nuclei and appearance of multilaminar ergastoplasm. An outstanding feature in all these lesions was the presence of dark fusiform epithelial cells. They were observed in the middle layers in the squamous metaplasias with severe atypia and appeared in all layers of the carcinomas in situ.
- Research Organization:
- Oak Ridge National Lab., TN
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 6500425
- Journal Information:
- Am. J. Pathol.; (United States), Journal Name: Am. J. Pathol.; (United States) Vol. 98:1; ISSN AJPAA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL TISSUES
ANIMALS
AROMATICS
BIOCHEMISTRY
BODY
CARBOHYDRATES
CARCINOGENESIS
CARCINOMAS
CHEMISTRY
CONDENSED AROMATICS
DISEASES
EPITHELIUM
GLYCOGEN
MAMMALS
MORPHOLOGICAL CHANGES
NEOPLASMS
ORGANIC COMPOUNDS
PATHOGENESIS
POLYSACCHARIDES
RATS
RESPIRATORY SYSTEM
RODENTS
SACCHARIDES
SECRETION
TISSUES
TOXICITY
TRACHEA
TRANSPLANTS
ULTRASTRUCTURAL CHANGES
VERTEBRATES