title: Mutation induction in cultured human cells after low-dose and low-dose-rate gamma-ray irradiation: detection by LOH analysis.
abstract: To study the genetic effects of low-doses and low-dose-rate ionizing radiation (IR), human lymphoblastoid TK6 cells were exposed to 30 mGy of gamma-rays at a dose-rate of 1.2 mGy/hr. The frequency of early mutations (EMs) in the thymidine kinase (TK) gene locus was determined to be 1.7 x 10(-6), or 1.9-fold higher than the level seen in unirradated controls. These mutations were analyzed with a loss of heterozygosity (LOH) detection system, a methodology which has been shown to be sensitive to the effects of radiation. Among the 15 EMs observed after IR exposure, 8 were small interstitial-deletion events restricted to the TK gene locus. However, this specific type of event was not found in unirradiated controls. Although these results were observed under the limited conditions, they strongly suggest that the LOH detection system can be used for estimating the genetic effects of a low-dose IR exposure delivered at a low-dose-rate.
authors.affiliation: Advanced Development and Support Center, The Institute of Physical and Chemical Research, Saitama, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Umebayashi
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Honma
authors.forename: Masao
authors.initials: M
authors.lastname: Suzuki
authors.forename: Hiromi
authors.initials: H
authors.lastname: Suzuki
authors.forename: Toru
authors.initials: T
authors.lastname: Shimazu
authors.forename: Noriaki
authors.initials: N
authors.lastname: Ishioka
authors.forename: Masaya
authors.initials: M
authors.lastname: Iwaki
authors.forename: Fumio
authors.initials: F
authors.lastname: Yatagai
mesh_terms: D002460:Cell Line; D004252:DNA Mutational Analysis / Q000379:methods*; D004307:Dose-Response Relationship, Radiation; D006580:Genetic Carrier Screening / Q000379:methods*; D006801:Humans; D019656:Loss of Heterozygosity / Q000235:genetics / Q000528:radiation effects; D008214:Lymphocytes / Q000201:enzymology* / Q000528:radiation effects*; D009154:Mutation / Q000528:radiation effects; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013937:Thymidine Kinase / Q000235:genetics* / Q000528:radiation effects*
chemical_list: D013937:Thymidine Kinase