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.
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.
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.
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.
Unknown authors · 2004
Case reports of peripheral neurological effects of radiofrequency radiation describe mainly disturbances of noxious sensation called dysaesthesia. Cases have arisen after exposure to much of the frequency range from low MHz to GHz. After very high intensity exposures nerves may be grossly injured; however, after lower intensity exposures which may result in dysaesthesia, ordinary nerve conduction studies demonstrate no abnormality although current perception threshold studies may. Only a small proportion of similarly exposed persons develop symptoms. Some observations are not consistent with the hypothesis that all health effects of radiofrequency radiation arise from thermal mechanisms.
Yao K, Wang KJ, Sun ZH, Tan J, Xu W, Zhu LJ, Lu de Q. · 2004
Researchers exposed cultured rabbit lens epithelial cells to continuous 2,450 MHz microwave radiation at power densities of 0.10, 0.25, 0.50, 1.00, and 2.00 mW/cm2 for 8 hours. P27Kip1 protein expression increased markedly but its mRNA levels did not change, and P21WAF1 protein and mRNA levels showed no detectable differences between exposed and control groups.
Zmyslony M, Rajkowska E, Mamrot P, Politanski P, Jajte J · 2004
Researchers tested whether weak 50 Hz magnetic fields affect the number of free oxygen radicals in rat lymphocytes in vitro. Rat lymphocytes were exposed for one hour to 50 Hz magnetic fields at 20, 40, or 200 μT, with the field axis either along or crosswise to Earth's static magnetic field. Only at 40 μT, when the field was directed along Earth's static magnetic field, was there a decrease in fluorescence compared to non-exposed samples.
Kim MJ, Rhee SJ. · 2004
Researchers exposed rats to 2.45 GHz microwave radiation for 15 minutes and then fed them diets containing 0%, 0.25%, or 0.5% catechin. Microwave exposure increased cytochrome P450 levels by 85% and NADPH-cytochrome P450 reductase activity by 29% compared with normal rats. It also raised superoxide radical concentrations by 35% and decreased superoxide dismutase activity by 34% and glutathione peroxidase activity by 28%. Catechin supplementation at 0.25% and 0.5% lowered superoxide radicals by 11% and 12%, increased superoxide dismutase activity by 19% and 25%, and kept glutathione peroxidase near normal.
Hinrichs H, Heinze HJ. · 2004
Researchers investigated potential effects of GSM 1800 electromagnetic fields on verbal memory encoding by recording event-related magnetic fields from the brain during subsequent memory retrieval. Twelve normal subjects each completed two experimental sessions, one with EMF exposure during the study phase and one without. Exposure to EMF changed an early (350-400 ms) task-specific component of the event-related magnetic field, indicating interference with item encoding. Behavioral measures were not significantly affected.
Kojima M et al. · 2004
Researchers exposed one eye each of 43 male pigmented rabbits to microwaves at 300 mW/cm2, either under systemic anesthesia or without anesthesia. Exposed eyes showed miosis, conjunctival congestion, corneal edema, and increased light scattering in the lens, and all of these anterior ocular changes disappeared within a week. Rabbits under systemic anesthesia showed much stronger symptoms, and their ocular temperatures were 2-9 degrees C higher than those without anesthesia.
Busljeta I, Trosic I, Milkovic-Kraus S. · 2004
Researchers exposed rats to 2.45 GHz radiation (WiFi frequency) for 2 hours daily and found it disrupted blood cell production in bone marrow while increasing genetic damage markers. These effects occurred at non-heating power levels, suggesting biological impacts below thermal thresholds.
Trosic I, Busljeta I, Pavicic I. · 2004
Researchers investigated the effect of 2.45 GHz microwave irradiation on blood-forming cells in rats. Rats were exposed to a field power density of 5-10 mW/cm2 and a whole-body average SAR of 1-2 W/kg for 2 hours a day, 7 days a week, for 2, 8, 15, or 30 days. A significant decrease in lymphoblast count was observed at 15 and 30 days, while other examined parameters did not differ significantly from sham-exposed controls.
Ding GR et al. · 2004
Researchers tested whether exposure to an extremely low frequency magnetic field affects hydrogen peroxide-induced cell death in human leukaemia HL-60 cells. Simultaneous treatment with the magnetic field and hydrogen peroxide for 24 hours significantly increased the number of apoptotic and necrotic cells compared with cells treated with hydrogen peroxide alone. The researchers found that active caspase-7 protein levels were higher in cells exposed to both the magnetic field and hydrogen peroxide than in those treated with hydrogen peroxide alone, and that poly(ADP-ribose) polymerase cleavage occurred earlier under combined exposure.
Munoz S, Sebastian JL, Sancho M, Miranda JM · 2004
Researchers calculated the transmembrane voltage induced on erythrocyte, codocyte, ovalocyte, and spherocyte cell models exposed to a linearly polarized electromagnetic plane wave at 1800 MHz. The induced voltage on the original erythrocyte shape was higher than on the altered cell geometries. Erythrocyte shape and membrane electric permittivity were found to play a fundamental role in the induced transmembrane voltage values. A finite element numerical technique with adaptive meshing was used for the calculations.
Ramundo-Orlando A, Liberti M, Mossa G, D'Inzeo G. · 2004
Enzyme activity decreased only at 5.6 W/kg, with no response at lower SAR values. When using deglycated ascorbate oxidase without oligosaccharide chains, microwave irradiation caused no enzyme activity changes, indicating the chains are necessary for the effect. Catalytic properties of both enzyme forms were unaffected by microwave exposure in solution or in liposomes, ruling out enzyme conformational changes as a mechanism. The authors concluded that oligosaccharide chains of ascorbate oxidase are critical for microwave effects on lipid membranes.
Zmyślony M et al. · 2004
