August 2006

RFR exposure and the immune system

Nasta and colleagues from Italy studied mice that were exposed to GSM-modulated 900 MHz radiofrequency radiation (RFR), and found no effects on the B-cells of the immune system or on antibody production.

Reference: Nasta F, Prisco MG, Pinto R, Lovisolo GA, et al. Effects of GSM-modulated radiofrequency fields on B-cell peripheral differentiation and antibody production. Radiation Research 2006;165:664-670.

No increase in micronuclei after RFR exposure

Scarfi and colleagues performed this study in the framework of the Cooperative Research and Development Agreement (CRADA) between the Cellular Telecommunications and Internet Association (CTIA) and the US FDA.

They exposed lymphocytes to RFR for 24 hours at 900 MHz frequency and found no evidence of genotoxic or cytotoxic effects from the RFR exposure. The study was done in two independent laboratories and the results were the same in the individual laboratories and when the slides were cross-checked by the scorers from the two laboratories.

For more see “Research – Toxicological - Cancer”.

Reference: Scarfi MR, Fresegna AM, Villani P, Pinto R, et al. Exposure to radiofrequency radiation (900 MHz, GSM signal) does not affect micronucleus frequency and cell proliferation in human peripheral blood lymphocytes: an interlaboratory study. Radiation Research 2006;165:655-663.

And another study shows lack of genotoxicity after RFR exposure

Micronuclei production was also looked for in another paper. Stronati and colleagues examined human lymphocytes after blood specimens were exposed to RFR from a 935 MHz signal for 24 hours. Other tests of genotoxicity likewise showed no effect. These included DNA strand breakage, chromosomal aberrations and changes in the speed of cell cycling.

For more see “Research – Toxicological - Cancer”.

Reference: Stronati L, Testa A, Moquet J, Edwards A, et al. 935 MHz cellular phone radiation. An in vitro study of genotoxicity in human lymphocytes. Int J Radiat Biol 2006;82:339-346

Two studies show no effect of RFR on gene expression

Two studies, one from USA and the other from Canada, were reported in a recent edition of “Radiation Research”. Each examined the effect of RFR on gene expression. The USA study, by Whitehead and colleagues, exposed mouse cells to RFR from a FDMA or CDMA field for 24 hours at a SAR of 5 W/kg. The Canadian study exposed human glioblastoma cells to a 1.9 GHz frequency field for 4 hours at SARs of 0.1, 1.0, or 10.0 W/kg. Neither study found any effect of the RFR on gene expression.

Assessment of gene expression using microarrays offers statistical challenges. There is considerable likelihood of false positives, given the large number of genes examined in these tests. Mayo et al., in the same issue of “Radiation Research”, examine these statistical issues. They also reviewed the statistical methods employed in the two papers by Whitehead et al. and Qutob et al., and found them to be appropriate.

For more, see “Research – Toxicological - Cancer”.

References: Whitehead TD, Moros EG, Brownstein BH, Roti Roti JL. Gene expression does not change significantly in C3H 10 T1/2 cells after exposure to 847.74 CDMA or 835.62 FDMA radiofrequency radiation. Radiation Research 2006;165:626-635.

Qutob SS, Chauhan V, Yauk CL, Douglas GR, et al. Microarray gene expression profiling of a human glioblastoma cell line exposed in vitro to a 1.9 GHz pulse-modulated radiofrequency field. Radiation Research 2006;165:636-644.

Mayo MS, Gajewski BJ, Morris JS. Some statistical issues in microarray gene expression data. Radiation Research 2006;165:745-748.

No change in proto-oncogenes or heat-shock proteins after RFR exposure

Chauhan and colleagues from Health Canada also published a recent paper showing no change in the expression of proto-oncogenes or heat-shock proteins when human cells were exposed to 1.9 GHz RFR at a SAR of either 1 or 10 W/kg for 6 hours.

For more, see “Research – Toxicological - Cancer”, and “Research-Toxicological-others-heat-shock response”.

Reference: Chauhan V, Mariampillai A, Gajda GB, Thansandote A, et al. Analysis of proto-oncogene and heat-shock protein gene expression in human derived cell-lines exposed in vitro to an intermittent 1.9 GHz pulse-modulated radiofrequency field. Int J Radiat Biol 2006;82:347-354.

Cerebral blood flow and exposure to cell phones

There have been two previous studies of the effect of RFR on cerebral blood flow (CBF) in humans. One of these studies, by Haarala et al (2003), suggested that there was no effect. The same group has carried out a new study with an improved design. They now report that CBF, measured by PET scanning, was increased in the prefrontal cortex in 12 volunteers who were exposed to RFR from a commercial cell phone. The authors suggest that this increased flow was due to neuronal activity induced by the RFR.

For more, see “Research – Clinical – cognitive function”.

Reference: Aalto S, Haarala C, Bruck A, Sipila H, et al. Mobile phone affects cerebral blood flow in humans. J Cereb Blood Flow Metab 2006;26:885-890.

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