Alice Collin

Study of p53 expression and post-transcriptional modifications after GSM-900 radiofrequency exposure of human amniotic cells†

The potential effects of radiofrequency (RF) exposure on the genetic material of cells are very important to determine since genome instability of somatic cells may be linked to cancer development. In response to genetic damage, the p53 protein is activated and can induce cell cycle arrest allowing more time for DNA repair or elimination of damaged cells through apoptosis. The objective of this study was to investigate whether the exposure to RF electromagnetic fields, similar to those emitted by mobile phones of the second generation standard, Global System for Mobile Communications (GSM), may induce expression of the p53 protein and its activation by post-translational modifications in cultured human cells. The potential induction of p53 expression and activation by GSM-900 was investigated after in vitro exposure of human amniotic cells for 24 h to average specific absorption rates (SARs) of 0.25, 1, 2, and 4 W/kg in the temperature range of 36.3-39.7 °C. The exposures were carried out using a wire-patch cell (WPC) under strictly controlled conditions of temperature. Expression and activation of p53 by phosphorylation at serine 15 and 37 were studied using Western blot assay immediately after three independent exposures of cell cultures provided from three different donors. Bleomycin-exposed cells were used as a positive control. According to our results, no significant changes in the expression and activation of the p53 protein by phosphorylation at serine 15 and 37 were found following exposure to GSM-900 for 24 h at average SARs up to 4 W/kg in human embryonic cells.

In vivo setup characterization for pulsed electromagnetic field exposure at 3 GHz.

An in vivo setup for pulsed electric field exposure at 3 GHz is proposed and characterized in this work. The exposure system allows far field, whole-body exposure of six animals placed in Plexiglas cages with a circular antenna. Chronic exposures under 18 W incident average power (1-4 kW peak power) and acute exposures under 56 W incident average power (4.7 kW peak power) were considered. Numerical and experimental dosimetry of the setup allowed the accurate calculation of specific absorption rate (SAR) distributions under various exposure conditions. From rat model numerical simulations, the whole-body mean SAR values were 1.3 W kg(-1) under chronic exposures and 4.1 W kg(-1) under acute exposure. The brain-averaged SAR value was 1.8 W kg(-1) and 5.7 W kg(-1) under chronic and acute exposure, respectively. Under acute exposure conditions, a 10 g specific absorption of 1.8  ±  1.1 mJ · kg(-1) value was obtained. With temperature rises below 0.8 °C, as measured or simulated on a gel phantom under typical in vivo exposures, this exposure system provides adequate conditions for in vivo experimental investigations under non-thermal conditions.

A Wideband Microwave Exposure Setup for Suspended Cells Cultures: Numerical and Experimental EM Characterization

An in vitro exposure setup developed to expose suspended cells in Petri dishes on a large frequency band up to a few gigahertz was studied. This system was based on far-field exposure with a horn antenna in an anechoic chamber. A specific incubator was designed with a water-cooling system for constant temperature inside the setup. Four exposed Petri dishes presented a similar specific absorption rate (SAR) distribution with a whole-volume SAR of 0.56 ±0.40 W/kg/Winc at 2.45 GHz. The incubator was equipped with a stirring mechanism allowing an homogenous distribution of temperature in the biological solution. The SAR was assessed over the 1.5-3 GHz frequency range. Using the temperature control and stirring, an increase of 0.4°C in temperature was observed after 2 h exposure at 2.45 GHz, 22 W incident power. This dosimetric study demonstrated the ability of this system to expose cells in suspension at different frequencies in a controlled environment.

Chromosomal studies of human amniotic cells exposed to GSM-900: Karyotyping and FISH

The possible effects of radiofrequency (RF) exposure on the genetic material of cells are very important to determine since DNA damage of somatic cells may be linked to cancer development. The first objective of our studies was to study the complete R-banded karyotype of cultured human amniotic cells exposed to RF similar to those emitted by mobile phones of second generation (GSM). Our second objective was to investigate whether the GSM-exposure may induce aneuploidy by FISH (Fluorescent in Situ Hybridization) using the same probes as those used by Mashevich et al. (2003) and Mazor et al. (2008).

Biological effects of radar type 3 GHz microwave exposure on Wistar rats

The aim of this work was to simulate human exposure to high power pulsed microwave (HPM) emitted by radars. The exposure of navy staff can be occasional, prolonged or repeated. A special emitting experimental device was developed in order to reproduce these exposure conditions with an experimental model of adult rat. Results obtained for 29 days after a single 3 GHz exposure (mean SAR 15 W/kg) will be presented. At day 30, the animals were sacrificed. Parameters related to the central nervous system, hematological and endocrine system were studied. The condition of rats was followed up by regular body weighing and clinical check-up. The data obtained did not show significant biological and behavioral effects after an acute exposure to radars HPM at 3 GHz.