In vitro increase of the fluid-phase endocytosis induced by pulsed radiofrequency electromagnetic fields: importance of the electric field component.

Nowadays, due to the wide use of mobile phones, the possible biological effects of electromagnetic fields (EMF) become a public health general concern. Despite intensive research, there are no widely accepted theories about the interactions between EMFs and living cells, and the experimental data are often controversial. We examined the effects of mobile phones EMF (envelope frequency of 217 Hz, carrier frequency of 900 MHz and pulse duration of 580 micros) or its pure, low-frequency pulsed electric field component on fluid-phase endocytosis. In both cases, with exposures exceeding 10 min, an increase of the fluid-phase endocytosis rate was observed ( approximately 1.5-fold), on three different cell types. This increase is an all-or-nothing type of response that is occurring for threshold values comprised between 1.3 and 2.6 W/kg for the delivered EMF powers and between 1.1 and 1.5 V/cm for the electric fields intensities depending upon the cell type. The electric component of these EMFs is shown to be responsible for the observed increase. Variations of frequency or pulse duration of the electric pulses are shown to be without effect. Thus, EMF, via their electrical component, can perturb one of the most fundamental physiological functions of the cells-endocytosis.

Evaluation of viability of retinal photoreceptor cells by using their endogenous electrical field.

The rod photoreceptor cells are electrical dipoles sustained by cell metabolic energy. Polarity of photoreceptor cells is directly connected to the so-called "dark current" which circulate along the living photoreceptors. Since only the living cells in a good functional state display electrical polarity, the orientation of photoreceptors in static electric field reflects their viability as long as it depends on the functionality of molecular mechanisms that maintain the dark current. Studying the rod cells' orientation in static electric field at different times after their isolation is thus an accurate way to evaluate the cell viability/degeneration. Retinal transplant experiments in animals and humans, which are presently in progress, require a quick and reliable viability test of cells/tissue to be transplanted. Checking the orientation pattern of rod photoreceptors in static electric field prior to transplantation is a candidate method for an accurate cell viability test.

The effects of low level microwaves on the fluidity of photoreceptor cell membrane.

Due to the extensive use of electromagnetic fields in everyday life, more information is required for the detection of mechanisms of interaction and the possible side effects of electromagnetic radiation on the structure and function of the organism. In this paper, we study the effects of low-power microwaves (2.45 GHz) on the membrane fluidity of rod photoreceptor cells. The retina is expected to be very sensitive to microwave irradiation due to the polar character of the photoreceptor cells [Biochim. Biophys. Acta 1273 (1995) 217] as well as to its high water content [Stud. Biophys. 81 (1981) 39].