Double strand break (DSB) repair kinetics in APDCs and PSFCs following irradiation. (a) Immunofluorescent foci of γ-H2AX. At the indicated times after 8 Gy of irradiation, cells were fixed and prepared for immunofluorescence staining. (b) Histograms of the number of γ-H2AX foci per nucleus 24 h after irradiation. Results are expressed as means ± SE of three different samples. *P < 0.05, **P < 0.001. Scale: 20 μm.