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MICRONUCLEI AND OTHER NUCLEAR ANOMALIES IN BUCCAL SMEARS: FIELD TEST IN SNUFF USERS
Citation:
Tolbert, P., C. Shy, AND J. Allen. MICRONUCLEI AND OTHER NUCLEAR ANOMALIES IN BUCCAL SMEARS: FIELD TEST IN SNUFF USERS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-92/445 (NTIS PB93141448).
Description:
A revised protocol for the exfoliated cell micronucleus assay was ie d-teste in a population exposed to a genotoxic agent at levels associated with a significant increase in cancer risk. The standard assay involves microscope examination of epithelial smears 0 determine the prevalence of micronucleated cells, an indication of chromosome breakage 0 mitotic interference. he assay was revised to increase specificity of the assay and to include separate scoring of other nuclear anomalies associated with cytotoxicity and genotoxicity. he modified assay was applied to buccal smears of 38 female snuff users and 15 non-users recruited from a North Carolina clinic. revalence of micronucleated cells was elevated in the snuff users compared to the non-users (prevalence ratio: 2.4, 95% C.I.: [1.1, 5.2]) and, to a lesser extent, in the habitual contact site compared to the distal buccal site within the snuff users (prevalence ratio: 1.5, C.I.: [0.9, 2.5]). The pattern of relative frequencies of several nuclear anomalies provided strong evidence of a cytotoxic effect of snuff, the prevalence ratios ranging from two to thirteen. Nuclear degenerative phenomena associated with cytotoxicity can be very difficult to distinguish from classical micronuclei; thus, the observed association of indicators of cytotoxicity with exposure introduces the possibility of bias away From the null in micronucleus findings due to differential misclassification. ntil methods to distinguish extra-nuclear bodies of different origins become available, investigators using this ass should focus on agents not thought to be cytotoxic.