title: Protective bystander effects simulated with the state-vector model.
abstract: Apoptosis induced in non-hit bystander cells is an important biological mechanism which operates after exposure to low doses of low-LET radiation. This process was implemented into a deterministic multistage model for in vitro neoplastic transformation: the State-Vector Model (SVM). The new model is tested on two data sets that show a reduction of the transformation frequency below the spontaneous level after exposure of the human hybrid cell line CGL1 to low doses of gamma-radiation. Stronger protective effects are visible in the data for delayed plating while the data for immediate plating show more of an LNT-like dose-response curve. It is shown that the model can describe both data sets. The calculation of the time-dependent numerical solution of the model also allows to obtain information about the time-dependence of the protective apoptosis-mediated process after low dose exposures. These findings are compared with experimental observations after high dose exposures.
authors.affiliation: Department of Materials Engineering and Physics, Division of Physics and Biophysics, University of Salzburg, Hellbrunnerstrasse 34, Salzburg, Austria. helmut.schoellnberger@sbg.ac.at
authors.forename: Helmut
authors.initials: H
authors.lastname: Schöllnberger
authors.forename: Peter M
authors.initials: PM
authors.lastname: Eckl