fibroblasts from patients with coronary atherosclerosis Increased radiosensitivity and radioresistant DNA synthesis in cultured

Abstract Cultured skin fibroblasts from five patients withatherosclerosis who underwent coronary artery bypass graftsurgery were compared with those from one ataxia telangiec-tasia (AT) homozygote, three AT heterozygotes, and fivehealthy subjects to determine their sensitivity to gamma radi-ation as determined by a colony survival assay. Fibroblastsfrom four of these patients were also compared with thosefrom two AT homozygotes, two AT heterozygotes, and threehealthy subjects to determine postirradiation [ 3 H]thymidineincorporation, indicating the levels of radioresistant DNAsynthesis (RDS). On the basis of colony survival assay, afterlong-term irradiation (at low dose rate, ie, 0.007 Gy/min),fibroblasts from all five patients with atherosclerosis exhibitedradiosensitivity that was intermediate between that of thehealthy subjects and that of patients with the known radiosen-sitive syndrome AT. However, there was a considerable inter-strain difference in the radiosensitivity of fibroblasts frompatients with atherosclerosis, with their mean D