ACTION OF A 50 HZ MAGNETIC-FIELD ON PROLIFERATION OF CELLS IN CULTURE

Proliferation of SV40-3T3 mouse fibroblasts and human HL-60 promyelocy tes was studied after treatment with a sinusoidal 2 mT(rms) 50 Hz magn etic field. A single exposure of 60 minutes caused quasicyclic changes in the cell number of SV40-313 cultures as function of time after tre atment, which was interpreted to be due to the induction of chronobiol ogical mechanisms by the field. Moreover, small variations in cell cyc le distribution were measured during postexposure incubation for both cell lines. To discriminate between the effect of the magnetic vector and the induced electric field HL-60 cell exposure was also performed on organ culture dishes. These dishes consist of two coaxially centere d, isolated compartments in which different electric field levels are induced in the medium during treatment. Cell growth was affected in th e outer compartment only where the induced electric field ranged from 8 to 12 mV(peak)/meter at 2 mT, but it was not affected in the inner c ompartment (field range 0-4 mV(peak)/meter). This suggests that the ef fects on cell growth are due to the induced electric field and are exp ressed only above a threshold of between 4 and 8 mV(peak)/meter. (C) 1 997 Wiley-Liss, Inc.