Chauhan V et al. · 2006
Researchers exposed human lymphoblastoma TK6 cells to 1.9 GHz pulse-modulated RF fields at SARs of 1 and 10 W/kg. They assessed expression of proto-oncogenes FOS, JUN, and MYC using real-time RT-PCR. They also monitored transcript levels of the heat-shock proteins HSP27 and inducible HSP70. Transcript levels in RF-exposed cells showed no significant difference compared to sham-exposed cells. Positive heat-shock controls showed significant elevation of HSP27, HSP70, FOS, and JUN, and a decline in MYC mRNA.
Sakuma N et al. · 2006
Researchers conducted a large-scale in vitro study to test whether modulated RF fields from mobile radio base stations act as a DNA damaging agent. Human glioblastoma A172 cells and normal human IMR-90 fibroblasts were exposed to 2.1425 GHz CW and W-CDMA radiation. A172 cells were exposed to W-CDMA at SARs of 80, 250, and 800 mW/kg and CW at 80 mW/kg for 2 and 24 hours, while IMR-90 cells were exposed to both modulations at 80 mW/kg for the same periods. No significant differences in DNA strand breaks were observed between exposed groups and sham controls using alkaline comet assays. The authors concluded that low-level exposures do not act as a genotoxicant up to a SAR of 800 mW/kg.
Maes A, Van Gorp U, Verschaeve L. · 2006
Researchers investigated cytogenetic effects in peripheral blood lymphocytes from subjects professionally exposed to mobile phone electromagnetic fields. The alkaline comet assay, sister chromatid exchange and chromosome aberration tests revealed no evidence of RFR-induced genetic effects. Blood cells were also exposed to mitomycin C to investigate possible combined effects of RFR and the chemical mutagen. No cooperative action was found between the electromagnetic field exposure and the mutagen using either the comet assay or SCE test.
Simkó M et al. · 2006
The study investigated Hsp70 expression and free radical release in human Mono Mac 6 cells exposed to ultrafine particles and radiofrequency electromagnetic fields. Ultrafine particle exposure increased free radical release by 40-45% above negative control, an effect stronger than heat treatment. Radiofrequency electromagnetic field exposure alone did not change free radical levels. Combined exposure to RF and ultrafine particles did not enhance the particle effect on free radicals. Heat treatment increased Hsp70 expression in a time-dependent manner, while ultrafine particles, RF fields, or their combination had no effect on Hsp70.
Lantow M, Lupke M, Frahm J, Mattsson MO, Kuster N, Simko M. · 2006
The study investigated whether 1,800 MHz RF-EMF can induce ROS release or Hsp70 expression changes in human blood cells using various exposure conditions. PMA treatment significantly increased ROS production in both monocytes and lymphocytes compared to sham or incubator controls. GSM-DTX exposure at 2 W/kg produced a significant difference in monocyte ROS compared to sham, but this was attributed to lower ROS values in the sham condition, while lymphocytes showed no ROS changes. Hsp70 expression in monocytes did not differ after GSM-DTX exposure at 2 W/kg for 1 hour compared to incubator or sham controls at any post-exposure time point.
Lantow M, Schuderer J, Hartwig C, Simko M. · 2006
Heat and PMA treatment significantly increased superoxide radical anions and ROS production in Mono Mac 6 cells. No significant differences in free radical production were detected after RF EMF exposure compared to controls. The GSM-DTX signal at 2 W/kg showed a significant difference versus sham due to a decreasing sham value, but this difference disappeared when compared to incubator controls. No significant effects on HSP70 expression were detected after RF EMF exposures.
Hamann W, Abou-Sherif S, Thompson S, Hall S. · 2006
Researchers applied pulsed radiofrequency (20 ms of 500-kHz RF pulses at 2 Hz, max 42°C) to the sciatic nerve or L4 anterior primary ramus in adult rats. Controls included sham-operated and L4 axotomised rats, and tissues were examined 14 days later. Axotomy upregulated ATF3 in L4 DRG neurons regardless of size. PRF applied near the DRG significantly and selectively increased ATF3 in small and medium neurons, while PRF applied to the sciatic nerve in mid-thigh caused no obvious changes.
Ferreira AR et al. · 2006
Researchers used the micronucleus assay to assess chromosomal damage in erythrocytes from rat offspring exposed to non-thermal UHF-EMF from a cellular phone during embryogenesis. The irradiated group showed a significant increase in micronuclei occurrence. No significant differences were found in any oxidative parameter of offspring blood and liver. The average number of pups in each litter was not significantly altered.
Christ A, Samaras T, Klingenböck A, Kuster N. · 2006
The study investigated electromagnetic near-field absorption in layered biological tissue from 30 MHz to 6000 MHz. Two effects can increase SAR in layered tissue versus homogeneous liquid: standing wave effects at larger distances depending on frequency and fat thickness, and high local skin absorption from reactive E-fields in the very close near-field. A conservative exposure estimate can be obtained by applying a multiplication factor of 1 to 3 to current dosimetric values.
Anghileri LJ, Mayayo E, Domingo JL, Thouvenot P. · 2006
The study aimed to evaluate health risks caused by radio frequency accelerated carcinogenesis and the importance of processes driven by the calcium ion signal. Exposed animals showed organ hypertrophy, lymphoid blood and ascites, solid tumours, and mortality that were very different from control animals. The results emphasized the role of calcium ion signal influx in the activation of oncogenes and the failure of thymus-determined immune defences.
Anghileri LJ, Mayayo E, Domingo JL. · 2006
The study investigated the effects of parenteral iron administration on the acceleration of lymphomagenesis by radiofrequency exposure using an animal model that develops spontaneous lymphomas with ageing. Complementary studies showed differences in absorption and excretion between ferric gluconate and ferric-ATP complex, and molecular structure-dependence in calcium cellular uptake. The results demonstrated a synergism between radiofrequency and ferric gluconate, and increased risk of radiofrequency exposure when simultaneous to parenteral iron administration.
Zhao R, Zhang SZ, Yao GD, Lu DQ, Jiang H, Xu ZP · 2006
Zeng Q, Chen G, Weng Y, Wang L, Chiang H, Lu D, Xu Z. · 2006
Researchers investigated gene and protein responses to GSM 1800 MHz RF EMF in human breast cancer MCF-7 cells using genomic and proteomic approaches. GeneChip analysis identified a handful of changed genes after exposure at SAR up to 3.5 W/kg for 24 hours, but these changes were not confirmed by RT-PCR. Proteome analysis found a few different proteins differentially expressed under continuous or intermittent exposure at SAR 3.5 W/kg for 24 hours or less, but the authors suggest these effects might have occurred by chance.
Zeng QL, Weng Y, Chen GD, Lu DQ, Chiang H, Xu ZP · 2006
Researchers exposed MCF-7 human breast cancer cells to GSM 1800 MHz RF EMF at 3.5 W/kg SAR for various durations and modes. They used 2-dimensional electrophoresis and PDQuest software to analyze protein expression. No differential proteins were found after 6 hours of continuous exposure. Eighteen differential proteins were detected after 3-hour intermittent exposure and seven after 12-hour continuous exposure. The analysis suggested that the differentially expressed proteins should be related to biosynthesization, signal transduction, and DNA damage and repair.
Wang J et al. · 2006
Researchers exposed A172 cells to 2450 MHz high-frequency electromagnetic fields at SARs of 5-200 W/kg and included heat controls at 38-44°C. HSP70 expression increased in a time- and dose-dependent manner at SARs above 50 W/kg for 1-3 hours, similar to heat controls. HSP27 expression did not change significantly with HFEMF exposure or heating, but HSP27 phosphorylation increased transiently at 100 and 200 W/kg, exceeding the effect of heating at 40-44°C, peaking after 1 hour at 100 W/kg.
Vanderwaal RP, Cha B, Moros EG, Roti Roti JL. · 2006
The radiofrequency exposures were 847 MHz TDMA at a SAR of 5 W kg-1 for 1, 2, or 24 h and 900 MHz GSM at a SAR of 3.7 W kg-1 for 1, 2, or 5 h. Acute hyperthermia at 45 degrees C increased the proportion of higher phosphorylated forms of HSP27. Exposure of HeLa S3 cells to 5 W kg-1 TDMA for 1, 2, or 24 h did not induce significant differences in HSP27 phosphorylation compared to incubator control or sham.
Takashima Y et al. · 2006
Researchers exposed cells to radio frequency electromagnetic fields at 2.45 GHz to examine cell growth, survival, and cell cycle distribution across a wide range of specific absorption rates. When cells were exposed to a continuous RF field at SARs from 0.05 to 100 W/kg for 2 h, cellular growth rate, survival, and cell cycle distribution were not affected. At 200 W/kg, the cell growth rate was suppressed and cell survival decreased, and the temperature of the medium rose to 44.1 degrees C. The researchers suggested that the proliferation disorder is caused by the thermal effect.
Hoyto A, Sihvonen AP, Alhonen L, Juutilainen J, Naarala J · 2006
Researchers investigated the effects of low-level radiofrequency radiation and elevated temperature on ornithine decarboxylase (ODC) activity in murine L929 fibroblasts. RF radiation did not affect cellular ODC activity. A slight temperature increase of 0.8-0.9 degrees C in the exposure system led to decreased ODC activity, which was verified by exposing cells to different temperatures in incubators.
Capri M et al. · 2006
Researchers exposed human peripheral blood mononuclear cells from young and elderly donors to radiofrequency radiation at 1,800 MHz and a Specific Absorption Rate of 2 W/kg, with or without mitogenic stimulation. However, RF exposure produced a slight but significant downregulation of CD95 expression in stimulated CD4+ T lymphocytes from elderly donors only.
Zhang DY, Xu ZP, Chiang H, Lu DQ, Zeng QL. · 2006
Researchers studied the effects of GSM 1800 MHz radiofrequency electromagnetic fields on DNA damage in Chinese hamster lung cells. Cells were intermittently exposed to GSM 1800 MHz RF EMF at a SAR of 3.0 W/kg for either 1 hour or 24 hours, using a pattern of 5 minutes on and 10 minutes off. After 24 hours of exposure, the percentage of gammaH2AX foci positive cells was 37.9 +/- 8.6%, significantly higher than the sham-exposed group at 28.0 +/- 8.4%. The 1-hour exposure showed no significant difference from sham exposure.
Lixia S et al. · 2006
Researchers exposed human lens epithelial cells (hLEC) to a 1.8 GHz GSM radiofrequency field at SARs of 1, 2, and 3 W/kg for 2 hours and then measured DNA damage, Hsp70 expression, and cell proliferation. DNA breaks at 1 and 2 W/kg were not significantly different from controls at any time point, while the 3 W/kg dose showed significantly increased DNA damage only at 0 and 30 minutes after exposure. Hsp70 protein expression was significantly increased at 2 and 3 W/kg, but Hsp70 mRNA expression did not change in any group, and cell proliferation was unaffected at all doses.
Whitehead TD et al. · 2005
The study aimed to confirm a previous report that CDMA and FDMA radiation increased Fos levels as cells entered plateau phase. Fos mRNA levels were not significantly different from sham exposure at either SAR level for any signal modulation. Therefore, the earlier results could not be confirmed.
Miyakoshi J et al. · 2005
Researchers exposed human glioma MO54 cells to a continuous wave 1950 MHz RF field at SARs of 1, 2, and 10 W/kg for up to 2 hours. Cell growth was assessed by counting cell numbers up to 4 days after exposure. RF exposure at 2 and 10 W/kg did not affect the growth of MO54 cells. However, exposure at 10 W/kg for 1 and 2 hours significantly decreased the protein level of phosphorylated Hsp27 at serine 78.
Lim HB, Cook GG, Barker AT, Coulton LA. · 2005
Researchers exposed human peripheral blood to 900 MHz fields at specific absorption rates of 0.4, 2.0, and 3.6 W/kg for durations of 20 minutes, 1 hour, and 4 hours. Heat stress at 42 degrees Celsius increased the number of cells expressing HSP70 and HSP27 in a time-dependent manner. No statistically significant difference in stress protein expression was detected after RF-field exposure.
Lee JS, Huang TQ, Lee JJ, Pack JK, Jang JJ, Seo JS. · 2005
Researchers exposed eight-week-old hsp70.1-deficient mice twice daily for 45 minutes with a 15-minute interval, five days a week for ten weeks at a whole-body average specific absorption rate of 0.4 W/Kg for both 849 MHz and 1763 MHz fields. They examined major tissues histopathologically, assessed cell proliferative activity immunocytochemically, measured apoptosis with a TUNEL assay, and evaluated heat shock protein expression and stress-activated kinase phosphorylation by western blot. No histopathological differences were found between sham- and RF-exposed mice, and there was no evidence of increased proliferative or apoptotic activity. Levels of HSP90, HSP70, and HSP25 showed no obvious changes, and RF exposure did not affect phosphorylation of ERK1/2, JNK1/2, or p38 MAPK.
