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.
Rollwitz J, Lupke M, Simkó M · 2004
Researchers studied the effects of 50 Hz magnetic fields on free radical production in mouse bone marrow-derived macrophages and monocytes. Exposure to the magnetic fields at a flux density of 1 mT produced a significant increase in free radical production in both cell types. The radicals produced were mainly superoxide anion radicals, found in macrophages at 33% and in their precursor cells at 24%.
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.
Lee BC et al. · 2004
Researchers investigated whether a 60 Hz magnetic field could affect the antioxidant defense system in mouse brain by measuring chemiluminescence and superoxide dismutase (SOD) activity in brain homogenates. A chemiluminescence measure linked to oxidative stress was significantly increased in mice exposed to 60 Hz, 12 G for 3 hours compared to the sham-exposed control group. Brain SOD activity was also significantly increased in the exposed group. The researchers suggest these results indicate the field could deteriorate the antioxidant defensive system through reactive oxygen species other than superoxide radicals.
Lai H, Singh NP · 2004
Researchers investigated how magnetic field exposure affected brain cell DNA in rats. Exposure to a 60-Hz magnetic field at 0.01 mT for 24 hours caused a significant increase in DNA single- and double-strand breaks, and prolonging the exposure to 48 hours caused a larger increase. Acute magnetic field exposure also increased apoptosis and necrosis of brain cells in the rat.
Koyama S et al. · 2004
Researchers tested whether an extremely low-frequency magnetic field (ELFMF) could affect mutations caused by hydrogen peroxide in pTN89 plasmids. Mutations were detected in the supF gene carried by the plasmids in Escherichia coli. The mutation frequency was 2.28×10−4 for hydrogen peroxide treatment alone, and 5.81×10−4 when the ELFMF was applied at the same time. No mutations were observed with ELFMF exposure alone, and the researchers indicated that the ELFMF may potentiate hydrogen peroxide-induced mutation.
Dasdag S et al. · 2003
Sixteen Sprague-Dawley rats were divided into exposed and sham-exposed groups of eight each. The exposed group received cell phone radiation for 20 minutes per day, seven days a week, for one month. No statistically significant alterations were found in any endpoints, including sperm count, morphology, testicular histology, lipid composition, malondialdehyde concentration, p53 immune reactivity, or rectal temperature.
Aweda MA, Gbenebitse S, Meidinyo RO · 2003
Researchers studied the effects of 2.45 GHz microwave exposure on the lipid peroxidation status of 120 Wistar rats at a power density of 6 mWcm(-2). Lipid peroxidation status in the rats was monitored for 8 weeks after irradiation using the thiobarbituric acid method. Microwave exposure raised the lipid peroxidation status from a mean control value of 4.18 x 10(-6)g 1(-1) to a maximum of 6.50 x 10(-6) g 1(-1) within the first 24 hours, after which it gradually returned toward the control value. The results demonstrated that microwave exposures cause a significant increase in lipid peroxidation status and that ascorbic acid and alpha-tocopherol had protective effects.
Jajte J, Zmyślony M, Rajkowska E. · 2003
Researchers examined whether melatonin and vitamin E could protect rat blood lymphocytes from lipid peroxidation caused by iron ions and a 7 mT static magnetic field in vitro. Simultaneous exposure to the 7 mT static magnetic field and iron ions produced a significant increase in lipid peroxidation end-products compared with control samples and those exposed to the field alone. When cells were pre-treated with melatonin or vitamin E before that same exposure, lipid peroxidation was significantly reduced, and melatonin was less effective than vitamin E under these conditions.
Unknown authors · 2002
EMF exposure increased sulfate incorporation, glycosaminoglycan content, chondrocyte number at day 8, cartilage volumetric density, and immunostaining for antibodies 3B3 and 5D4. DNA content and thymidine incorporation did not differ between groups, indicating no increase in cell proliferation. Proteoglycan and glycosaminoglycan molecular sizes and composition were unchanged, showing accelerated synthesis of normal cartilage molecules. Expression of proteoglycan and type II collagen mRNA increased, along with greater immunoreactivity for 3B3 and 504, suggesting faster chondrocyte differentiation and phenotypic maturation.
Logani MK, Agelan A, Ziskin MC. · 2002
The study examined the effect of millimeter electromagnetic waves on catalase activity in mouse blood to understand mechanisms involved in its reduction. SKH-1 hairless mice were irradiated on their midbacks with 42.2±0.2 GHz millimeter waves at an incident power density of 31±5 mW/cm2 and a peak SAR of 622±100 W/kg. MW irradiation before or after cyclophosphamide administration did not significantly reduce the toxic effect of cyclophosphamide on catalase activity in mouse blood.
Stopczyk D et al. · 2002
Researchers assessed the effect of mobile phone electromagnetic fields on SOD-1 activity and MDA level in human blood platelets exposed to 900 MHz for 1, 3, 5, and 7 minutes. SOD-1 activity was significantly depleted after 1, 5, and 7 minutes of exposure and increased after 3 minutes compared with controls. MDA concentration increased significantly after 1, 5, and 7 minutes and decreased after 3 minutes compared with controls. The authors concluded that oxidative stress from microwave exposure may cause adverse cellular changes and systemic disturbances.
Shallom JM et al. · 2002
Researchers exposed chick embryos to athermal 915 MHz microwave radiation to test for induction of the stress protein Hsp70. Hsp70 levels increased within 2 hours, reaching a maximum about 30% above controls by 3 hours. Embryos pre-exposed to microwave radiation before hypoxic stress had significantly higher survival after re-oxygenation than non-exposed controls (P < 0.05).
Liu X, Shen H, Shi Y, Chen J, Chen Y, Ji A. · 2002
Burch JB et al. · 2002
Researchers evaluated cellular telephone use and melatonin metabolite excretion in two groups of male electric utility workers. Participants collected urine samples and recorded telephone use over three workdays while personal magnetic field and light exposures were measured. In Study 1, no change in 6-OHMS excretion was observed with daily cellular telephone use over 25 minutes.
Irmak MK et al. · 2002
Researchers investigated the influence of electromagnetic radiation from a digital GSM mobile telephone at 900 MHz on oxidant and antioxidant levels in rabbits. They measured adenosine deaminase, xanthine oxidase, catalase, myeloperoxidase, superoxide dismutase, glutathione peroxidase activities, nitric oxide, and malondialdehyde levels in sera and brains of exposed and sham-exposed rabbits. Serum SOD activity increased and serum NO levels decreased in exposed rabbits compared to sham-exposed rabbits, while other parameters did not change.
Akoev IG et al. · 2002
The study explored how the frequency of microwave modulation affected the activity of several enzymes and affective rat behavior at intensities of 0.8 to 10 microW/cm2. The researchers proposed that free radical processes may play a role in the nonlinear effects observed and in the modification of emotional behavior in animals. The study also postulated a protective role for monoaminoxidase, which is located on the outer surface of mitochondria and deaminates monoamines.
Liu Y, Weng E, Zhang Y, Hong R. · 2002
Researchers exposed mice to a 50 Hz sinusoidal electromagnetic field at 0.2 mT or 6.0 mT for 2 weeks, and measured markers of the antioxidant system and cell membrane fluidity in brain and liver tissue. Malondialdehyde content in brain and liver increased with exposure, while total antioxidant capability decreased at both field strengths. When electromagnetic field exposure was combined with lead, the researchers observed synergic effects on lipid peroxidation.
Jajte J, Grzegorczyk J, Zmyślony M, Rajkowska E. · 2002
Researchers exposed rat blood lymphocytes to a 7 mT static magnetic field for 3 hours in Helmholtz coils, with some samples also treated with ferrous chloride at 10 μg/ml. The static magnetic field alone and iron ions alone each produced no significant effect on cell viability. When the field and iron ions were combined, there was a significant increase in apoptotic and necrotic cells and significant alterations in cell viability. The researchers suggested that a 7 mT static magnetic field in the presence of Fe2+ ions can increase the concentration of oxygen free radicals and thus may lead to cell death.
Moustafa YM, Moustafa RM, Belacy A, Abou-El-Ela SH, Ali FM. · 2001
Researchers investigated the effect of acute exposure to radiofrequency fields from commercially available cellular phones on oxidative stress parameters in 12 healthy adult male volunteers. Each volunteer placed the phone in his pocket in standby position with the keypad facing the body. The parameters measured were lipid peroxide and the activities of superoxide dismutase (SOD), total glutathione peroxidase (GSH-Px) and catalase. Plasma lipid peroxide increased significantly after 1, 2, and 4 hours of exposure. SOD and GSH-Px activities in erythrocytes showed significant reduction, while catalase activity did not decrease significantly.
Yang R, Chen J, Deng Z, Liu X, · 2001
Researchers cultured pig retinal ganglion cells in vitro, added vitamin E at different concentrations, and exposed them to 2450 MHz microwave radiation at 30 mW/cm² for 1 hour. Microwave exposure caused cell congregation, axon disappearance, mitochondria and endoplasmic reticulum swelling, and apoptosis. Vitamin E groups showed no obvious changes under optical microscope, though electron microscopy revealed light mitochondria swelling with intact cristae. The researchers concluded that microwave induced morphological damage and vitamin E reduced this damage to some extent.
Pashovkina MS, Akoev IG · 2001
Researchers exposed donor blood to pulse-modulated microwaves at 2375 MHz with intensities of 2 microW/cm2 and 8 microW/cm2, pulse modulation from 50 to 390 Hz, for 5 minutes. Aspartate aminotransferase activity was strongly dependent on both modulation frequency and microwave intensity. Maximum activity was found at 390 Hz and 8 microW/cm2, reaching about six times the control level.
S. Kwee, P. Raskmark & S. Velizarov · 2001
Researchers exposed transformed human epithelial amnion (AMA) cells to a microwave field simulating the GSM signal at 960 MHz for 20 minutes. The field generated a specific absorption rate (SAR) of 2.1 mW.kg−1 in the cells, and exposures were carried out at temperatures of 35, 37, and 40 ± 0.1°C. Higher amounts of Hsp-70 were found in exposed cells at 35 and 37°C compared with sham-exposed cells, while Hsp-27 showed no significant response. The researchers considered these effects athermal because the field strength was much lower than the safety standard for absence of heat generation by microwave fields.
Simkó M, Droste S, Kriehuber R, Weiss DG · 2001
Researchers examined the effects of 50 Hz electromagnetic fields on phagocytosis and free radical production in mouse bone marrow-derived macrophages exposed in vitro to magnetic field densities of 0.5 to 1.5 mT. Short-time exposure of 45 minutes resulted in a significantly increased phagocytic uptake of 36.3% plus or minus 15.1%, as measured by the internalization rate of latex beads. A significant increase in superoxide production was also detected after exposure to electromagnetic fields. Because co-exposure to electromagnetic fields and TPA showed no additive increase in bead uptake, researchers concluded that the electromagnetic fields-induced stimulation does not involve the protein kinase C signal transduction pathway.
Jajte J, Zmyślony M, Palus J, Dziubałtowska E, Rajkowska E. · 2001
Researchers used the alkaline comet assay to assess DNA damage in rat peripheral blood lymphocytes exposed in vitro to iron ions and a 50 Hz magnetic field. Cell samples were incubated for 3 hours in Helmholtz coils at 7 mT 50 Hz, and some were treated with ferrous chloride at 10 μg/ml during that exposure. A significant increase in cells with DNA damage was found only after simultaneous exposure to ferrous chloride and the 7 mT 50 Hz magnetic field, compared to control samples or those incubated with ferrous chloride alone. When cells were treated with melatonin before that combined exposure, the number of damaged cells was significantly reduced, with the reduction reaching about 50% at 0.5 mM and about 100% at 1.0 mM.
