Ultrastructural characteristics of carcinogen-induced nondysplastic changes in tracheal epithelium
Nondysplastic hypotrophic and metaplastic epithelial alterations induced by dimethylbenz(a)anthracene in isogenic tracheal transplants were studied by light and electron microscopy 3 to 24 months after cessation of a 4-week carcinogen exposure. Hypotrophic epithelium observed at all time points was characterized by the presence of nonciliated cells that adopted either cuboidal or squamous shapes, forming simple or bistratified epithelia. Most of these cells, as well as some metaplastic cells, exhibited features of mucin-secreting cells. The metaplastic epithelia showed nonkeratinizing squamous metaplasia, closely related to transitional metaplasia, and keratinizing squamous metaplasia, which presented either an atrophic or an acanthotic epithelium. Although many of these epithelia showed morphologic features of normal stratified epithelia, several nonkeratinizing squamous metaplasias and acanthotic keratinizing squamous metaplasias exhibited some irregularities, probably representing very early atypical ultrastructural features (i.e., perinuclear concentration of tonofilament bundles, the presence of dark and clear basal epithelial cells, interruptions and alterations of the basal lamina). These features were not observed in a group of early squamous metaplasias studied for comparative purposes 2 weeks after cessation of dimethylbenz(a)anthracene exposure, which were characterized by a combination of degenerative phenomena and increased cell proliferation.
- Research Organization:
- Oak Ridge National Lab., TN
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 6407901
- Journal Information:
- Am. J. Pathol.; (United States), Vol. 98:1
- Country of Publication:
- United States
- Language:
- English
Similar Records
Distribution and ultrastructural characteristics of dark cells in squamous metaplasias of the respiratory tract epithelium. [Rats]
In vitro development of oncogenicity in cell lines established from tracheal epithelium preexposed in vivo to 7,12-dimethylbenz(a)anthracene
Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ULTRASTRUCTURAL CHANGES
CONDENSED AROMATICS
TOXICITY
EPITHELIUM
ATROPHY
CARCINOGENESIS
CELL PROLIFERATION
MORPHOLOGY
TRACHEA
TRANSPLANTS
ANIMAL TISSUES
AROMATICS
BODY
MORPHOLOGICAL CHANGES
ORGANIC COMPOUNDS
PATHOGENESIS
PATHOLOGICAL CHANGES
RESPIRATORY SYSTEM
TISSUES
560305* - Chemicals Metabolism & Toxicology- Vertebrates- (-1987)
550800 - Morphology
550900 - Pathology