Kwee S, Raskmark P, Velizarov S (2001)

These authors exposed human epithelial amnion cells to 960 MHz radiation for 20 minutes at a very low SAR of 0.0021 W/kg. The temperature in the exposure incubator was maintained at 35, 37, or 40 degrees centigrade in different experiments. Immediately after exposure, and after 60minutes, 90 minutes, and 24 hours of incubation, the presence of heat-shock proteins (HSPs) was determined by immunological staining. Sham cells, unexposed to the radiation, were used as controls.

At all three temperatures there were significantly greater amounts of HSP-70 in the exposed cells than in the sham-exposed cells. The amounts were less at 40° C than at the lower temperatures. The amounts of HSP-70 were highest immediately after exposure and decreased over time, and were undetectable at 2.5 hours.

In view of the low field strengths, the authors considered the observed changes to be an athermal effect.