title: Interaction between radiation-induced adaptive response and bystander mutagenesis in mammalian cells.
abstract: Two conflicting phenomena, the bystander effect and the adaptive response, are important in determining biological responses at low doses of radiation and have the potential to have an impact on the shape of the dose-response relationship. Using the Columbia University charged-particle microbeam and the highly sensitive AL cell mutagenic assay, we reported previously that nonirradiated cells acquired mutagenesis through direct contact with cells whose nuclei had previously been traversed with either a single or 20 alpha particles each. Here we show that pretreatment of cells with a low dose of X rays 4 h before alpha-particle irradiation significantly decreased this bystander mutagenic response. Furthermore, bystander cells showed an increase in sensitivity after a subsequent challenging dose of X rays. Results from the present study address some of the pressing issues regarding both the actual target size and the radiation dose response and can improve on our current understanding of radiation risk assessment.
authors.affiliation: Center for Radiological Research, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA. hz63@columbia.edu
authors.forename: Hongning
authors.initials: H
authors.lastname: Zhou
authors.forename: Gerhard
authors.initials: G
authors.lastname: Randers-Pehrson
authors.forename: Charles R
authors.initials: CR
authors.lastname: Geard
authors.forename: David J
authors.initials: DJ
authors.lastname: Brenner
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Hall
authors.forename: Tom K
authors.initials: TK
authors.lastname: Hei
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology* / Q000528:radiation effects*; D000512:Alpha Particles; D000818:Animals; D024201:Bystander Effect / Q000528:radiation effects*; D018957:CD59 Antigens / Q000528:radiation effects; D002880:Chromosomes, Human, Pair 11 / Q000528:radiation effects; D006224:Cricetinae; D004307:Dose-Response Relationship, Radiation; D005786:Gene Expression Regulation / Q000528:radiation effects; D006801:Humans; D006822:Hybrid Cells / Q000502:physiology* / Q000528:radiation effects*; D008322:Mammals; D016296:Mutagenesis / Q000502:physiology / Q000528:radiation effects*; D011836:Radiation Tolerance / Q000528:radiation effects; D018570:Risk Assessment / Q000379:methods*; D014965:X-Rays
chemical_list: D018957:CD59 Antigens