Figure 3. Monitoring basal and IR-induced DNA damage in PBL from different age groups. Irradiated PBL were re-cultivated and fixed at indicated time points. 53BP1 and γH2AX foci were detected by immunofluorescence microscopy and 50-200 nuclei per donor scored. (A) 53BP1 foci. Dots, mean values; bars, SEM; female: n=14 (young), n=11 (old); male: n=5 (young), n=7 (old) (