To study the effects of exposure to a 1.8 GHz radiofrequency electromagnetic field on epidermal growth factor receptor cluster formation (as initial process for signal transduction) and phosphorylation in human amniotic cells.
|Exposure duration||continuous for 15 min|
|Pulse width||0.576 ms|
|Duty cycle||12.5 %|
|Repetition frequency||217 Hz|
|Setup||waveguides placed inside an incubator with constant temperature of 37°C; six petri dishes with monolayers of cells placed on a dish holder in the H-field maximum of the standing wave inside the waveguide and were simultaneously exposed to E-polarization|
|Sham exposure||A sham exposure was conducted.|
|SAR||4 W/kg||maximum||-||-||0.1, 0.5, 1, 2, 4 W/kg|
The data showed that, compared with sham exposure, radiofrequency exposure at specific absorption rate of 0.5, 1, 2, or 4 W/kg for 15 minutes significantly induced EGF receptor clustering and enhanced phosphorylation on the tyrosine-1173 residue in amniotic cells, whereas exposure to a SAR of 0.1 W/kg did not cause a significant effect. However, the results showed also that there was no additional significant increase in effects at intensities higher than 0.5 W/kg.
Based on these findings, the authors conclude that membrane receptors could be one of the main targets that radiofrequency exposure interacts with cells, and the dose-rate threshold, in the case of EGF receptors, is between SAR of 0.1 and 0.5 W/kg.