Lupke M, Rollwitz J, Simkó M. · 2004
Researchers investigated how 50 Hz extremely low frequency magnetic fields activate human cells to release reactive oxygen intermediates. They examined free radical production in human umbilical cord blood-derived monocytes and in human Mono Mac 6 cells. Exposure to 1 mT ELF-MF for 45 minutes produced a significant increase in superoxide radical anion production of up to 1.4 fold and an increase in ROS release of up to 1.2 fold in monocytes. Mono Mac 6 cells showed superoxide radical anion and ROS production of up to 1.4 and 1.5 fold, respectively, leading the researchers to suggest these cells are more sensitive to ELF-MF than monocytes.
Unknown authors · 2004
Researchers conducted a population-based case-control study in Norway to assess residential and occupational exposure to 50-Hz magnetic fields and breast cancer risk. Cases of breast cancer diagnosed from 1980 to 1996 were identified in a cohort of women living near a high-voltage power line, and each case was matched to two controls by year of birth, municipality, and cohort entry year. Residential exposure was calculated from the magnetic fields generated by the power lines before diagnosis, while occupational exposure was based on an exposure matrix. Women with residential exposure had an odds ratio of 1.58 (95% CI: 1.30, 1.92) for breast cancer, whereas the highest occupational exposure yielded an odds ratio of 1.13 (95% CI: 0.91, 1.40).
Tahvanainen K et al. · 2004
Researchers conducted a randomized, double-blind, placebo-controlled crossover trial with 32 healthy subjects exposed to 900 MHz (2 W) and 1800 MHz (1 W) cellular phone signals and sham exposure in separate sessions. Arterial blood pressure and heart rate did not change significantly during or after the 35-minute RF exposures at either frequency compared to sham exposure. Blood pressure was measured with an arm cuff and heart rate was recorded during and after each 35-minute exposure session.
Sommer AM, Streckert J, Bitz AK, Hansen VW, Lerchl A · 2004
Survival rate and lymphoma incidence did not differ between exposed and sham-exposed mice. Exposed mice gained more weight than sham-exposed mice. The data do not support the hypothesis that 900 MHz fields are a significant risk factor for lymphoma in this genetically predisposed strain.
Cobb BL, Jauchem JR, Adair ER. · 2004
Researchers exposed rats to 2450 MHz fields at 0.6 W/kg for 45 minutes daily over 10 days in circularly polarized waveguides and gave them a pre-exposure injection of a psychoactive compound or saline. Error rate analysis showed no significant effect of microwave exposure, no drug effect, and no exposure-drug interaction, while performance improved across test days indicating learning. Time to criterion showed no significant exposure effect but a significant drug effect, a significant test day effect, and a significant drug-by-test-day interaction. The authors concluded there is no evidence that microwave radiation exposure under the tested parameters caused decrements in spatial memory learning.
Unknown authors · 2004
Researchers compared two Sprague-Dawley substrains, SD1 and SD2, for magnetic field effects on cell proliferation, susceptibility to DMBA-induced mammary cancer, and tumor development in the DMBA model. The SD1 substrain was considered MF-sensitive and was compared with SD2 from the same breeder. Magnetic field exposure significantly increased mammary tumor development and growth in SD1 rats but not in SD2 rats. No enhanced cell proliferation was determined after magnetic field exposure in SD2 rats, unlike in SD1 rats. The researchers concluded that genetic background plays a pivotal role in magnetic field exposure effects.
Unknown authors · 2004
German researchers found that 50 Hz power-line magnetic fields significantly increased breast cancer development in one substrain of laboratory rats but had no effect on another genetically similar substrain. This finding helps explain why different research teams studying the same EMF exposure have reached conflicting conclusions about cancer risks.
Ayata A et al. · 2004
Thirty Wistar-Albino rats were assigned to control, irradiated, and irradiated-plus-melatonin groups, and the irradiated group received 900 MHz, 2 W radiation for 30 minutes daily over 10 days. The melatonin group received 10 mg/kg/day melatonin in tap water for 10 days before irradiation. Skin samples were analyzed for malondialdehyde, hydroxyproline, superoxide dismutase, glutathione peroxidase, and catalase. Radiation significantly increased MDA, hydroxyproline, CAT, and GSH-Px and decreased SOD; melatonin reversed the increases in MDA, hydroxyproline, CAT, and GSH-Px but did not prevent the SOD decrease. The results suggest that 900 MHz radiation increases fibrosis and lipid peroxidation in rat skin and that melatonin can reduce these effects.
Ayata A et al. · 2004
Researchers exposed rats to 900 MHz mobile phone radiation for 30 minutes daily over 10 days and found significant skin damage, including increased fibrosis (tissue scarring) and oxidative stress markers. When rats were pre-treated with melatonin, a natural antioxidant hormone, most of the radiation-induced skin damage was prevented. This suggests that mobile phone radiation can harm skin tissue through oxidative stress, but protective measures may help reduce this damage.
Curcio G et al. · 2004
Researchers randomly assigned subjects to two groups exposed to 902.40 MHz EMF either before or during testing sessions. Subjects completed four performance tasks under double-blind conditions while tympanic temperature was measured five times per session. Results showed improved simple and choice reaction times and increased local temperature on the exposed region after at least 25 minutes of exposure.
Lagroye I et al. · 2004
The study aimed to investigate the effect of 2450 MHz pulsed-wave microwaves on DNA damage in rat brain cells and whether proteinase K is needed to detect such damage. Rats exposed to γ-rays showed significant DNA damage using both comet assay versions independent of proteinase K. Neither assay version detected any difference in comet length or normalized comet moment between sham-exposed and microwave-exposed rats regardless of proteinase K inclusion. No DNA damage was detected in brain cells after exposure to 2450 MHz pulsed-wave microwaves at 1.2 W kg−1 regardless of proteinase K inclusion. The results support the conclusion that low-level 2450 MHz pulsed-wave microwave exposures do not induce DNA damage detectable by the alkaline comet assay.
Hook et al. · 2004
Researchers exposed mouse immune cells to cell phone radiation at 835-847 MHz for over 20 hours to test whether radiofrequency signals cause oxidative stress (cellular damage from harmful molecules). They found no evidence that either FMCW or CDMA modulated signals at 0.8 W/kg caused oxidative stress, cellular damage, or changes in the cells' natural antioxidant defenses. The study suggests that cell phone-type radiation at these levels does not trigger the cellular stress responses that can lead to health problems.
Hook, G. · 2004
The study measured intracellular oxidants, glutathione disulfide accumulation, antioxidant enzyme activities, nitric oxide production, and cell viability. FMCW- and CDMA-modulated RF radiation did not alter any measured oxidative stress parameters or cell toxicity.
Markkanen A et al. · 2004
Researchers exposed wild-type and cdc48-mutant yeast cells to 900 or 872 MHz RF fields with or without UV radiation at elevated temperature. Amplitude modulated RF exposure significantly enhanced UV-induced apoptosis in cdc48-mutated cells, but unmodulated fields at the same SAR had no effect. Apoptosis was measured using the annexin V-FITC method with flow cytometry.
Ozguner F, Aydin G, Mollaoglu H, Gokalp O, Koyu A, Cesur G. · 2004
Researchers used thirty male Wistar-Albino rats divided into a nontreated control group, an irradiated group, and an irradiated group that also received melatonin. The irradiated group received 900 MHz radiation for 10 days at 30 minutes per day, and skin grafts were taken from the thoraco-abdominal area at the end of the tenth day. In the irradiated group, researchers observed increased thickness of stratum corneum, atrophy of epidermis, papillamatosis, basal cell proliferation, hypergranulosis, capillary proliferation, and impairment in collagen tissue distribution compared to the control group. Most of these changes, except hypergranulosis, were prevented with melatonin treatment.
Unknown authors · 2004
Researchers exposed whole blood samples from five donors to a 50 Hz, 1 mT magnetic field for 2 hours. They used comet assay, sister chromatid exchange, chromosome aberration, and micronucleus tests to assess DNA damage. No significant differences were found between exposed and unexposed samples in any genotoxicity test. A slight but significant decrease in cell proliferation occurred in exposed samples and in samples also exposed to X-rays.
Koyama S, Isozumi Y, Suzuki Y, Taki M, Miyakoshi J. · 2004
Researchers exposed Chinese hamster ovary CHO-K1 cells to 2.45-GHz electromagnetic fields for 2 hours at SARs of 5, 10, 20, 50, 100, and 200 W/kg to study micronucleus formation. Micronucleus frequency in cells exposed at SARs lower than 50 W/kg did not differ from sham-exposed controls. At SARs of 100 and 200 W/kg, micronucleus frequency was significantly higher than in sham-exposed controls. The researchers also found that micronucleus frequency increased in a temperature-dependent manner when cells were heat-treated at temperatures from 38 to 42 degrees C.
Koyama S, Isozumi Y, Suzuki Y, Taki M, Miyakoshi J · 2004
Japanese researchers exposed Chinese hamster cells to 2.45 GHz radiation (the same frequency as microwave ovens and WiFi) for 2 hours at various power levels. They found that high-intensity exposures (100-200 W/kg) caused significant chromosome damage, while lower levels showed no effect. The damage appeared to be caused by heating rather than the radiation itself.
Chemeris NK et al. · 2004
Researchers investigated genotoxic effects of HPPP EMF (8.8 GHz, 180 ns pulse width, peak power 65 kW, repetition rate 50 Hz) on erythrocytes of the frog Xenopus laevis. They used the alkaline comet assay to assess DNA single-strand breaks and alkali-labile lesions. Blood samples were exposed for 40 minutes in a rectangular waveguide with a specific absorption rate of about 1.6 kW/kg. The temperature rise in blood samples at steady state was 3.5 +/- 0.1 degrees C, and the increase in DNA damage was induced by this temperature rise.
Unknown authors · 2004
Researchers exposed human peripheral blood samples to 50 Hz magnetic fields ranging from 0 to 100 microT rms for 4 hours at 37°C. The magnetic-field exposure had no detectable effect on expression of the genes encoding HSP27, HSP70A, or HSP70B. In contrast, heating at 42°C for 2 hours increased HSP27, HSP70A, and HSP70B expression by 10-, 5-, and 12-fold respectively. At 40°C, magnetic-field exposure did not increase gene expression compared to incubation at 40°C without field exposure. The findings suggest that power-frequency electromagnetic fields are not a universal stressor, unlike physical agents such as heat.
Sandrini L et al. · 2004
Researchers created a female dielectric anatomical model and compared power absorption in male and female models from 0.1 to 4 GHz. Whole-body-averaged SAR was higher in the female model, mainly due to a thicker subcutaneous fat layer. Maximum 1 g and 10 g averaged SAR did not depend on gender because it occurs in regions without subcutaneous fat.
Papageorgiou CC et al. · 2004
Ten women and nine men performed a short memory task during baseline and during exposure to a 900 MHz signal. Baseline EEG energy was higher in men than in women, and EMF exposure decreased EEG energy in men but increased it in women. Memory performance did not change with EMF exposure or gender.
Aran JM et al. · 2004
In the first experiment, guinea pigs were exposed to GSM microwaves at SARs of 1, 2, and 4 W/kg for 1 hour per day, 5 days per week, for 2 months. In the second experiment, guinea pigs were exposed at 4 W/kg and auditory brainstem response thresholds were monitored. Repeated-measures ANOVA showed no difference in DPOAE amplitudes or ABR thresholds between exposed and sham-exposed groups. Acute exposure for 1 hour also produced no statistically significant change in ABR thresholds. In vitro, organs of Corti from newborn rats exposed to 1 W/kg for 24-48 hours appeared normal under light microscopy after 2-3 days of culture.
Pyrpasopoulou A et al. · 2004
Researchers exposed pregnant rats to pulsed GSM-like radiofrequency radiation at 9.4 GHz and 5 microW/cm2 during early gestation. They measured bone morphogenetic protein and receptor expression in newborn kidneys using semi-quantitative duplex RT-PCR. Exposure increased BMP-4 and BMPR-IA expression and decreased BMPR-II expression, with statistical significance depending on exposure timing. Immunohistochemistry and in situ hybridization revealed aberrant expression and localization of these molecules. The authors suggest these molecular changes do not affect renal organogenesis but may reflect a developmental delay, and that exposure timing influences effects.
Anderson, L. · 2004
Researchers conducted a two-year chronic bioassay to determine whether long-term exposure to a 1.6 GHz radiofrequency field would affect cancer incidence in Fischer 344 rats. Timed-pregnant rats were assigned to far-field RF Iridium or sham groups, with whole-body exposures starting at 19 days gestation for 2 hours per day, 7 days per week until weaning. Offspring then received near-field head-first exposures 2 hours per day, 5 days per week from 36 days old until 2 years of age at brain SAR levels of 1.6 W/kg, 0.16 W/kg, or sham. No statistically significant differences were seen among groups for live pups per litter, survival index, weaning weights, clinical signs, or neoplastic lesions, and male survival was similar across groups while female cage controls had reduced survival time.
