title: Rapid recovery in human diploid fibroblasts.
abstract: Rapid split dose and single dose recovery were examined in exponentially growing and in density inhibited, stationary phase culture of human diploid fibroblasts. The cultures were exposed to cobalt-60 gamma rays at a dose-rate of 50 rad/s:0-90 min were allowed between exposures or following a single exposure prior to subculture at low density. A rapid phase of recovery occurred which was of greater magnitude in the plateau phase cultures. Dose-dependent rapid recovery occurred within 2-10 min of the initial exposure, and was greater following single dose versus split dose irradiations. When the post-irradiation temperature was maintained at 37 degrees C, two phases of recovery were observed, one at early times (2-10 min) and one later (30-90 min). No recovery was observed with incubation at 4 degrees C, whereas incubation at room temperature (25 degrees C) allowed rapid recovery (2-10 min) to take place, but not the slower process (30-90 min). The hypothesis that this rapid recovery phenomenon is related to cell-to-cell contact and to repair of potentially lethal damage is discussed.
mesh_terms: D002460:Cell Line; D002470:Cell Survival / Q000528:radiation effects; D003037:Cobalt Radioisotopes; D004171:Diploidy; D004307:Dose-Response Relationship, Radiation; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology / Q000528:radiation effects*; D005720:Gamma Rays; D006801:Humans; D013696:Temperature
chemical_list: D003037:Cobalt Radioisotopes