Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2008.Includes bibliographical references (p. 42-44).The bystander effect describes radiation-induced biological effects in nonirradiated cells that have received signals from irradiated cells. In a co-culture experiment, the bystander signaling is proposed to occur via the medium. Using a co-culture setup, the work in this thesis investigates the effects of temperature as an experimental parameter and linear energy transfer (LET) dependence on the bystander effect. Using the micronucleus assay and primary human AG01522 fibroblast cells co-cultured as both the target and bystander cells, the incidence of micronuclei in both X-ray irradiated and alpha particle irradiated bystander experiments were ~2 fold over control averages. In the temperature experiment, there were no significant differences between bystander cells co-cultured with cold (4°C) target cells and those co-cultured with warm control target cells. These results have shown, for AG01522 fibroblasts, that the bystander effect is independent of temperature and LET.by Carrie C. Buchanan.S.B
