EMF Database abstract: MEASUREMENT OF DNA DAMAGE AFTER EXPOSURE TO ELECTROMAGNETIC RADIATION IN THE CELLULAR PHONE COMMUNICATION FREQUENCY BAND (835.62 AND 847.74 MHz).

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Last modified on: Monday, July 31, 2000
Copyright © 1994-2008, Information Ventures, Inc.

MEASUREMENT OF DNA DAMAGE AFTER EXPOSURE TO ELECTROMAGNETIC RADIATION IN THE CELLULAR PHONE COMMUNICATION FREQUENCY BAND (835.62 AND 847.74 MHz).
(Eng.) Malyapa, R. S.; Ahern, E. W.; Straube, W. L.; Moros, E. G.; Pickard, W. F.; Roti Roti, J. L. [Radiation Oncology Center, Mallinckrodt Inst. of Radiology, Washington Univ., 4511 Forest Park Blvd., St. Louis, MO 63108 (R.S.M., E.W.A., W.L.S., E.G.M., J.L.R.R.); Dept. of Electrical Engineering, Washington Univ., St. Louis, MO 63130 (W.F.P.)] Radiat Res 148(6):618-627; 1997

The authors investigated the DNA-damaging potential of radiofrequency (RF) radiation in commercial cellular phone bands (835.62 and 847.74 MHz) in mammalian cells. Mouse C3H 10T1/2 fibroblasts and human glioblastoma U87MG cells in the exponential phase of growth were exposed to frequency modulated continuous wave (FMCW) RF radiation with a carrier frequency of 835.62 MHz and code division multiple access (CDMA) radiation centered on 847.74 MHz for 2, 4, or 24 hr. The FMCW and CDMA sources were supplied by Motorola, Inc. The exposures were performed using the radial transmission line (RTL) system at Washington Univ., St. Louis, MO which was utilized by the authors in a previous study with 2,450-MHz continuous wave microwave radiation (Malyapa et al., Radiat Res 148:608-617, 1997; BENER Abstract No. 17234). The SAR was determined to be 0.6 +/- 0.3 W/kg for both the FMCW and CDMA exposures. The temperatures in the RTLs were monitored continuously and maintained at 37 C. Control cell cultures were sham irradiated. Some cells were irradiated with cesium-137 gamma rays as a positive control using the procedure described by Malyapa et al. After irradiation, the extent of DNA damage in the cells was determined using the alkaline comet assay as described by Olive et al. (Exp Cell Res 198:259-269, 1992). The data were tested statistically using Student's t-test. Irradiation of the positive controls with gamma radiation indicated that the comet assay was sensitive enough to detect DNA damage after doses on the order of 1.0 centigray or higher. With increasing damage, there was an increase in the normalized comet moment and comet length. No significant difference in the level of DNA damage was seen between irradiated C3H or U87MG cells and their sham-irradiated controls. Additionally, exponentially growing and plateau phase cultures of C3H cells were irradiated with FMCW or CDMA radiation for 2 hr and then incubated for 4 hr at 37 C before being analyzed for DNA damage. This experiment was done to simulate, under in vitro conditions, the reported results of Lai and Singh which indicated a period of post-irradiation incubation either maintained or increased the level of DNA damage in rat brain cells irradiated in vivo with 2,450-MHz microwaves (Int J Radiat Biol 69:513-521, 1996, BENER Abstract No. 14736). Exposure to FMCW or CDMA radiation for 2 hr followed by the 4-hr post-irradiation incubation again did not result in any detectable DNA damage. Another experiment was conducted to determine if treating the cells with bromodeoxyuridine (BrdU), which is known to sensitize proliferating cells to X-radiation and ultraviolet radiation damage, would interact with FMCW and CDMA radiation to produce or enhance detectable DNA damage. Exponentially growing C3H cells were labeled with 10 uM BrdU for 24 hr and then exposed to FMCW and CDMA RF radiation for 2, 4, or 24 hr. Again, no evidence of DNA damage could be detected. The authors concluded that exposure of U87MG and C3H cells to 0.6-W/kg, 835.62-MHz FMCW and 847.74-MHz RF radiation for 2, 4, or 24 hr under several culture conditions did not produce any detectable DNA damage as determined by the comet assay. These results suggest that exposure at 37 C to FMCW or CDMA radiation at SARs likely to be encountered during routine cellular phone use will not cause DNA damage. (20 Refs). [Copyright 2000, Information Ventures, Inc.]

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