Canova, S., Fiorasi. F., Mognato. M., Grifalconi, M, Reddi, E., Russo, A. and Celotti, L. “Modeled Microgravity” Affects Cell Response to Ionizing Radiation and Increases Genomic Damage. Radiat. Res. 163, 191–199 (2005). The aim of this work was to assess whether “modeled microgravity” affects cell response to ionizing radiation, increasing the risk associated with radiation exposure. Lymphoblastoid TK6 cells were irradiated with various doses of γ rays and incubated for 24 h in a modeled microgravity environment obtained by the Rotating Wall Vessel bioreactor. Cell survival, induction of apoptosis and cell cycle alteration were compared in cells irradiated and then incubated in 1g or modeled microgravity conditions. Modulation of genomic damage induced by ionizing radiation was evaluated on the basis of HPRT mutant frequency and the micronucleus assay. A significant reduction in apoptotic cells was observed in cells incubated in modeled microgravity after γ irradiation compared with cells mainta...