title: Effective target size for the induction of bystander effects in medium transfer experiments.
abstract: Although radiation-induced bystander effects are frequently observed biological phenomena, the mechanism for these effects has not been fully determined. The target-hit theory and related concepts from microdosimetry provide a convenient formalism to help identify the nature of the targets responsible for initiating the emission of diffusible factors in medium transfer experiments. We used the microdosimetric models proposed by Stewart et al. (Radiat. Res. 165, 460-469, 2006) to analyze the results of published medium transfer experiments for gamma-ray doses in the range of 0.04 mGy to 5 Gy. The analysis suggests that the effective size of the target responsible for initiating signal emission in HPV-G human keratinocyte donor cells is approximately 2 microm.
authors.affiliation: Medical Physics and Applied Radiation Sciences Department, McMaster University, Hamilton, Ontario, Canada L8S 4K1. Zhengfeng.Liu@hrcc.on.ca
authors.forename: Zhengfeng
authors.initials: Z
authors.lastname: Liu
authors.forename: William V
authors.initials: WV
authors.lastname: Prestwich
authors.forename: Robert D
authors.initials: RD
authors.lastname: Stewart
authors.forename: Soo Hyun
authors.initials: SH
authors.lastname: Byun
authors.forename: Carmel E
authors.initials: CE
authors.lastname: Mothersill
authors.forename: Fiona E
authors.initials: FE
authors.lastname: McNeill
authors.forename: Colin B
authors.initials: CB
authors.lastname: Seymour
mesh_terms: D024201:Bystander Effect / Q000502:physiology* / Q000528:radiation effects*; D002460:Cell Line; D003198:Computer Simulation; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D015603:Keratinocytes / Q000502:physiology* / Q000528:radiation effects*; D008954:Models, Biological; D011829:Radiation Dosage