Changes in levels of c-myc and histone H2B following exposure of cells to low-frequency sinusoidal electromagnetic fields: evidence for a window effect.

Human HL-60 cells were exposed for 20 min to an electromagnetic field at frequencies ranging from 15 to 150 Hz and at densities from 0.2 to 2.3 mT (2 to 23 gauss). Following each exposure, quantitative levels of c-myc and histone H2B transcripts were determined by dot-blot hybridization analyses and compared with unexposed control samples. The most pronounced increase in each transcript occurred after exposure at 45 Hz, with levels more than four times that found in unexposed controls.