December 2007

RFR exposure in animals and cancer (1)
Another study fails to confirm Repacholi's results

In 1997 Repacholi and colleagues reported a two-fold increase in non-lymphoblastic lymphoma in Pim1 transgenic mice exposed for two 30 minute periods per day for 18 months to 217-pulsed 900 MHz RF fields. An Australian study by Utteridge et al. (2002) failed to replicate these findings. The study of Oberto et al., part of the PERFORM A program of the Fifth Framework European program, is another attempt to replicate the results of Repacholi et al.  Oberto's study did not show any effect on the incidence of tumours at any site, and therefore the results of Repacholi et al. could not be confirmed. The authors suggest that the results of Repacholi et al. were likely due to an unexpectedly low incidence of lymphomas in their control group.

Reference: Oberto G, Rolfo K, Yu P, Carbonatto M, et al. (2007): Carcinogenicity study of 217 Hz pulsed 900 MHz electromagnetic fields in Pim1 transgenic mice. Radiat Res 168:316-326.
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RFR exposure in animals and cancer (2)
Long-term RFR exposure in rats does not increase cancer incidence

This study by Smith and colleagues was done under the auspices of the EU Commission's PERFORM-A program. It attempted to overcome some of the shortcomings that had been present in other carcinogenicity studies in animals. A total of 1170 rats were included. The rats were exposed to either a 902 MHz GSM signal, or to a 1747 MHz DCS signal, at 3 different SAR levels. One additional group was sham-exposed for each modulation, and a further group was used as cage controls. There was no adverse response to the RF-exposure. In particular, there were no significant differences in the incidence of primary neoplasms, and the number of benign and malignant neoplasms between the rats exposed to wireless communication signals and rats that were sham exposed.

Reference: Smith P, Kuster N, Ebert S, Chevalier HJ (2007): GSM and DCS wireless communication signals: Combined chronic toxicity/carcinogenicity study in the Wistar rat. Radiat Res 168:480-492.
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RF-exposed rats show improved learning and memory, but no structural changes in brain

Kumlin et al. exposed Wistar rats for 2 hours a day, 5 days a week, from age 3 to 8 weeks, to RFR at 900 MHz frequency (similar to that from a GSM phone). The whole body average SAR was 0.3 or 3 W/kg. Four different sets of behavioural tests were done. The only test to show a significant difference between RF- and sham-exposed groups was the Morris water maze test. In this the RF-exposed groups had improved learning and memory. There were no degenerative changes, dying neurons, or effects on leakage of the blood-brain barrier.

For more, see "Research - Laboratory studies - Brain function".

Reference: Kumlin T, Iivonen H, Miettinen P, Juvonen A, et al. (2007): Mobile phone radiation and the developing brain: behavioral and morphological effects in juvenile rats. Radiat Res 168: 471-479.
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Exposure to RFR from a cell phone reduces sperm motility in rats

Yan and colleagues evaluated the effect of exposure to RFR from a cell phone could affect sperm fertility. They exposed 8 rats to RFR from a cell phone for 6 hours a day for 18 weeks. Sperm motility was significantly different in the exposed animals compared with a sham group. A molecular study of the epididymes revealed an increase in messenger RNA for two surface adhesion proteins. The authors suggest that the sperm changes could be related to the increase in these proteins, which normally serve to encourage adhesion between sperm and egg.

Reference: Yan JG, Agresti M, Bruce T, Yan YH, et al. (2007): Effects of cellular phone emissions on sperm motility in rats. Fertil Steril 88:957-964.
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For more, see "Research - Laboratory - reproductive studies".

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