title: Radiation dose-dependent variations of micronuclei production in cytochalasin B-blocked human lymphocytes.
abstract: Using the cytokinesis-block technique, lymphocytes from healthy volunteers (n = 9) were evaluated for 1) the radiation dose-response curve for micronuclei (MN) expression; 2) technique variables on the yield of MN; and 3) the shortest lymphocyte incubation time required for the MN assay. We found that the best fitting of relationships between increasing MN production and increasing irradiation dose (0-4.0 Gy) was the linear-quadratic model as expressed by the yield equation Y = C+alpha D+beta D2 (P = 0.0003). When lymphocytes were irradiated in vitro with 2.0 Gy and harvested at various time intervals, MN increased during the entire 84 hr culture time. The radiation caused a division delay in lymphocyte as indicated by an increased frequency of mononucleated cells and a decreased number of mitotic indices. The data showed that a shortened culture time (60 hr) for the MN assay is possible and that binucleated cells with > or = 3 MN were found only in cells irradiated at > or = 2.0 Gy. These findings suggest that scoring of MN in lymphocytes may be a practical biological dosimeter for the rapid screening of accidental radiation exposure victims, especially when their clinical manifestations are not obvious.
authors.affiliation: Department of Radiation Oncology, Leo W. Jenkins Cancer Center, East Carolina University School of Medicine, Greenville, North Carolina.
authors.forename: T K
authors.initials: TK
authors.lastname: Lee
authors.forename: A L
authors.initials: AL
authors.lastname: Wiley
authors.forename: J D
authors.initials: JD
authors.lastname: Esinhart
authors.forename: L D
authors.initials: LD
authors.lastname: Blackburn
mesh_terms: D000328:Adult; D002453:Cell Cycle / Q000528:radiation effects; D002478:Cells, Cultured; D003571:Cytochalasin B / Q000494:pharmacology*; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008214:Lymphocytes / Q000528:radiation effects* / Q000648:ultrastructure; D048629:Micronuclei, Chromosome-Defective / Q000528:radiation effects*
chemical_list: D003571:Cytochalasin B