Oxygen enhances lethal effect of high‐intensity, ultrashort electrical pulses

The study explored the effect of ambient oxygen on mammalian cell survival after exposure to 10 ns duration, high voltage electrical pulses (nsEP, 80–90 or 120–130 kV/cm; 200–400 pulses per exposure). Cell samples were equilibrated with pure nitrogen, atmospheric air, or pure oxygen prior to the nsEP treatment and were returned to the incubator (air + 5% CO 2 ) shortly after the exposure. The experiments established that survival of hypoxic Jurkat and U937 cells exceeded that of air‐equilibrated controls about twofold ( P  < .01). Conversely, saturation of the medium with oxygen prior to exposure decreased Jurkat cell survival about 1.5 times, P  < .01. Attenuation of the cytotoxic effect under hypoxic conditions resembled a well‐known effect of oxygen on cell killing by sparsely ionizing radiations and may be indicative of the similarity of underlying cell damage mechanisms. Bioelectromagnetics 27:221–225, 2006. Published 2005 Wiley‐Liss, Inc.