Fig. 2.

The surviving fractions of bystander V79 cells are plotted as a function of the nuclear-averaged dose in the irradiated cells. Cells were incubated with (open circles) or without (closed circles) the nitric oxide (NO)-specific scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO), commencing immediately after irradiation. Data were taken from at least three independent experiments. The error bars represent standard errors (SEs). An asterisk indicates P < 0.05, and double asterisks indicate P < 0.01.