ELECTRIC AND MAGNETIC NOISE BLOCKS THE 60-HZ MAGNETIC-FIELD ENHANCEMENT OF STEADY-STATE C-MYC TRANSCRIPT LEVELS IN HUMAN LEUKEMIA-CELLS

We have previously demonstrated that exposure of human cultured cells to 60 Hz sinusoidal magnetic fields causes an increase in steady state transcript levels for the proto-oncogene c-myc. A study by Litovitz e t al. (T.A. Litovitz D. Krause and J.M. Mullins, Biochem. Biophys. Res . Commun., 178(1991)862) suggests that the induction of bioeffects fro m exposure to 60 Hz fields requires that the exposure field be coheren t for some minimum length of time (approximately 10s). A related study demonstrated that these effects can be blocked by superposition of te mporally incoherent magnetic noise fields. In this paper we investigat e whether or not the superposition of a magnetic noise field can block the bioeffect of a coherent 60 Hz magnetic field on the transcript le vels of the photo-oncogene c-myc in HL60 cells. Experiments were perfo rmed using band-limited magnetic noise fields (30-90 Hz, 6.7 mu T rms) , and coherent 60 Hz magnetic fields (6.7 mu T rms). The results show that exposure to the 60 Hz field alone produces approximately a 40% en hancement in the steady level of the c-myc transcript. Superposition o f the noise field on the 60 Hz field inhibited the enhancement of the c-myc transcript to the extent that no statistically significant was o bserved. This study provides additional proof of the coherence time re quirement, and of the validity of the noise superposition method to bl ock electric and magnetic field induced bioeffects.