Table 1. Effects of KU55933, PFT-μ and ZVAD-fmk on frequencies of X-irradiation-induced chromosomal aberrations at 48 h post irradiation in resting HPBLs.

Treatment	Chromosomal aberrations/100 cells		% Aberrant cells
	Breaks	Dicentrics+rings
Ctrl	0.7±0.3	0.5±0.5	1.2±0.8
KU55933	0.7±0.6	0	0.7±0.6
PFT-μ	0	0	0
ZVAD-fmk	0.3±0.6	0	0.3±0.6
IR	13.8±2.5**	14.1 ±2.2**	21.3±3.3**
KU55933+IR	24.2±2.3**§§	23.7±3.7***§	40.7±5.0**§§
PFT-μ+IR	22.3±2.4***§	20.7±2.8**§	34.7±2.4**§§
ZVAD-fmk+IR	17.9±5.8*	13.5±4.9*	25.6±4.8**

Resting HPBLs were pretreated with 10 μM KU55933 for 2 h, 20 μM PFT-μ for 5 h or 100 μM ZVAD-fmk for 1 h followed by irradiation with 2 Gy X-rays, and incubated with PHA and colcemid for 48 h. The metaphase cells were then harvested, and a total of 100 metaphase cells were analyzed. The values represent the means±S.D. of HPBLs from three individual donors. *P<0.05, **P<0.01 and ***P<0.001, compared with non-irradiated control and inhibitor treatment alone; ^§ P<0.05 and ^§§ P<0.01, compared with IR alone.