Diverse Effects of Wideband Intense, Non-Ionizing Radiation on Cells and Tissues

Ionizing radiation can be an environmental health risk as well as a cancer therapeutic, but similar roles for non-ionizing radiation are controversial. We have examined effects of wideband, intense non-ionizing radiation applied to cells and tissues as nanosecond pulsed electric fields (nsPEFs). Compared to conventional electroporation pulses, nsPEFs have shorter pulse durations (ges10 ns) and higher electric fields (~300 kV/cm). For these short pulses we have observed a number of nsPEF-induced effects on biological cells and tissues, including apoptosis induction and tumor regression at high electric fields, as well as calcium mobilization, platelet aggregation and enhanced gene transcription at lower, sublethal electric fields. When nsPEFs are below the plasma membrane (PM) charging time constant (~100 ns), effects on intracellular membranes are appreciable. Thus, it is possible to observe effects on intracellular structures (membranes) and functions without observing effects on the PM. For Jurkat or HL-60 cells exposed to 10 ns or 60 ns pulses, mobilization of calcium from intracellular stores is observed at significantly lower electric fields than electric fields needed for PM electroporation or transport. However, as the electric field and/or the pulse duration are increased, it is possible to observe effects on the PM. Thus, as the pulse duration increases there is a cell type-specific increase in effects at the PM, as well as on intracellular structures and functions