ID Number		971
Study Type		In Vitro
Model		900 MHz (GSM) exposure of skin fibroblasts and analysis of gene expression
Details		Skin cells were exposed to 900 MHz (GSM) for 1 hour by placing a call (“hooking up” to the network) and analyzed for proliferation, changes in morphology, and gene expression. Such an exposure would provide unknown and variable SAR, although the authors report a value of 0.6 W/kg. Gene expression screening was performed using nylon membranes dotted with 82 different cDNA clones and assorted controls. The authors report exposure caused changes in cell morphology and expression of genes involved in mitogenic signal transduction (MAP kinase kinase 3, G2/mitotic-specific cyclin G1), growth inhibition (TGF beta), and apoptosis (bax). There was also a significant increase in DNA synthesis and intracellular mitogenic second messenger formation that corresponded to a high level of MAP kinase gene expression. The authors conclude that electromagnetic fields may have significant biological effects on human skin fibroblasts.
Findings		Effects
Status		Completed With Publication
Principal Investigator		University of Firenze, Italy
Funding Agency		Private/Instit.
Country		ITALY
References		Pacini, S et al. Oncology Research / Anti-Cancer Drug Design, (2002) 13:19-24
Comments		Exposure by hook-up to the network results in an unknown power level and an unknown SAR to the cells. Further, under conditions of speech inactivity, the phone software often directs the phone to compress transmitted data and skip multiple frames, further potentially varying SAR. 900 MHz GSM operation is generally at higher power (2 watt peak, 250 mW average) than 1800 MHz operation (1 watt peak, 125 mW average) using dual band GSM transcievers, and although the authors state the frequency of exposure at 902 MHz GSM, it is not clear if this ever varied over the course of the study due to high traffic hand-off or other factors to distal 900 MHz cell sites or sites using 1800 MHz operation. Finally, signal from the nearest network can change over time and thus repeated studies, even if all other conditions are maintained constant, may be performed under different conditions of exposure. The reported average SAR 0.6 W/kg is not necessarily what that particular phone was operating at throughout the experiment. Even more importantly, there was no good control. Phone "on" may surely have generated heat due to battery and circuitry (unrelated to RF) that the phone "off" control condition may not have replicated. Temperature measurements were performed at "plate level" and reported to show no changes in temperature in exposed samples - ambient temperature for the 1 hour exposure was reported as 26 degrees C.