title: Dose dependence of radiation-induced micronuclei in cytokinesis-blocked human lymphocytes.
abstract: Following selection of appropriate culture conditions, various experiments were conducted to evaluate the suitability of the micronucleus assay in cytokinesis-blocked lymphocytes for biological dosimetry purposes. A dose-effect relationship was determined, based on the frequency of micronuclei induced by various doses of 60Co gamma-rays. The data were best fitted to a linear-quadratic model. To validate the system, an attempt was made to estimate unknown dose levels from the yield of micronuclei, by inverting the derived dose-response function. It was concluded that the assay provides a valid approach for dose assessment. The size of radiation-induced micronuclei was measured in relation to the dose. A significant difference in the proportion of large micronuclei between high and low doses was observed. The chromosomal composition of micronuclei, detected by immunofluorescent staining of kinetochores, showed that only a small proportion of micronuclei contains kinetochore. The possible contribution of various mechanisms for the formation of large radiation-induced micronuclei is discussed.
authors.affiliation: Department of Human Genetics, National Institute of Health, Lisbon, Portugal.
authors.forename: M J
authors.initials: MJ
authors.lastname: Silva
authors.forename: A
authors.initials: A
authors.lastname: Carothers
authors.forename: A
authors.initials: A
authors.lastname: Dias
authors.forename: J H
authors.initials: JH
authors.lastname: Luis
authors.forename: J
authors.initials: J
authors.lastname: Piper
authors.forename: M G
authors.initials: MG
authors.lastname: Boavida
mesh_terms: D000328:Adult; D002138:Calibration; D002453:Cell Cycle / Q000502:physiology; D002455:Cell Division / Q000528:radiation effects; D002478:Cells, Cultured; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008214:Lymphocytes / Q000166:cytology / Q000502:physiology / Q000528:radiation effects*; D048629:Micronuclei, Chromosome-Defective / Q000528:radiation effects*; D015162:Micronucleus Tests; D015203:Reproducibility of Results