60 Hz (56 od skupno 1242 raziskav)
"Our meta-analysis provided conclusive data that ELF-MFs can increase apoptosis in cancer and normal cells. Furthermore, there is a possibly individual intensity and time range with maximum created effect according to window effect."
"The present study has demonstrated that exposure to ELF-MFs may evoke the changes in the levels of biogenic amines, amino acid and NO in the brain although the extent and property vary with the brain areas. However, the mechanisms remain further to be characterized."
"We demonstrated that the 2 epidermal keratinocytes responded to ELF-EMFs differently. To further validate this finding, we simultaneously exposed the NHEK and HaCaT cells to ELF-EMFs in the same incubator for 168 h and observed the cell growths. The simultaneous exposure of the two cell types results showed that the NHEK and HaCaT cells exhibited distinct responses to ELF-EMFs. Thus, we confirmed that the biological effects of ELF-EMFs in epidermal keratinocytes are cell type specific. Our findings may partially explain the inconsistent results of previous studies when comparing results across various experimental models."
"Clearly, much more work needs to be done to understand the
basic mechanisms responsible for this syndrome. However,
this report adds to the developing evidence that EHS is a real
disease, that a significant number of people suffer from EHS,
and that—beyond taking steps to reduce EMF exposure—we
have very limited knowledge of how to prevent and treat the
"According to the results of this study, ELF-MF exposure could impair oxidant-antioxidant function and might increase oxidative stress and lipid peroxidation. Antioxidant capability was dependent on the duration and continuity of ELF-MF exposure."
"Actions of ELF-EMFs on cytokine gene expression were additionally evaluated and found rapidly modified. Confronted with co-exposure to H2O2-induced oxidative stress, ELF-EMF proved not as well counteracted and resulted in a decline in CAT activity and a rise in O2(-) levels. Together these studies support the further evaluation of ELF-EMF exposure in cellular and in vivo preclinical models to define mechanisms potentially impacted in humans."
"ELF-MF significantly induced concomitant increase in superoxide dismutase without alteration in glutathione peroxidase activity. While glutathione contents were not altered, ascorbic acid levels were significantly decreased by ELF-MF exposure. These results indicate that ELF-MF may induce oxidative stress in mouse cerebellum. However, the mechanism remains further to be characterized."
"The subject demonstrated statistically reliable somatic reactions in response to exposure to subliminal EMFs under conditions that reasonably excluded a causative role for psychological processes. EMF hypersensitivity can occur as a bona fide environmentally inducible neurological syndrome."
"The radical pair mechanism and related cryptochromes (CRY) molecules have recently been identified in birds and other non-mammalian species, as a sensor of the geomagnetic field, involved in navigation. The hypothesis has to be tested in mammalian models. CRY, which is part of the molecular circadian clock machinery, is a ubiquitous protein likely to be involved in cancer cell growth and DNA repair. In summary, we now have some clues to test for a better characterization of the interaction between ALL and ELF MFs exposure."
"Our results suggest that repeated exposure to ELF-MF leads to prolonged locomotor stimulation and long-term expression of FRA in the striatal complex of the mice via stimulation of dopaminergic D1 receptor."
"Though results from this study suggest a reduction of human standing balance with MF exposure, as well as an increase of physiological tremor amplitude within the frequency range associated with central nervous system contribution, no exposure effect appeared on other investigated parameters (e.g., EEG or voluntary motor control). These results suggest that 1 h of 60 Hz, 1,800 uT MF exposure may modulate human involuntary motor control without being detected in the cortical electrical activity."
"Children living within 200m of power lines presented an increased risk of ALL (OR 1.67; 95% CI 0.49-5.75), compared to children living at 600m or more of power lines. For those living within 50m of power lines the OR was 3.57 (95% CI 0.41-31.44)."
"Our study revealed that ELF-MF exposure might influence the activity of endocrine cells, an important element of the intrinsic regulatory system in the digestive tract. The pathophysiological character of these changes and the mechanism responsible for neuroendocrine cell are still unclear and require further studies."
"RESULTS: GSH concentration was significantly lower in the heart of all experimental animals when compared to the control group; furthermore, the decrease was higher in the liver of restrained animals. SOD activity was lower in the plasma of restrained and EMF exposed animals compared to unrestrained rats. There were no significant differences in CAT activity and TBARS levels among all the experimental groups vs. the control group.
CONCLUSION: Two hours of 60 Hz EMF exposure might immediately alter the metabolism of free radicals, decreasing SOD activity in plasma and GSH content in heart and kidney, but does not induce immediate lipid peroxidation. Oxidative stress induced by movement restraint was stronger than that produced by EMF."
"We investigated the effects of extremely low frequency time-varying magnetic fields (MFs) on human normal and cancer cells. Whereas a single exposure to a 60-Hz time-varying MF of 6mT for 30min showed no effect, repetitive exposure decreased cell viability. This decrease was accompanied by phosphorylation of y-H2AX, a common DNA double-strand break (DSB) marker, and checkpoint kinase 2 (Chk2), which is critical to the DNA damage checkpoint pathway. In addition, repetitive exposure to a time-varying MF of 6mT for 30min every 24h for 3days led to p38 activation and induction of apoptosis in cancer and normal cells. Therefore, these results demonstrate that repetitive exposure to MF with extremely low frequency can induce DNA DSBs and apoptosis through p38 activation. These results also suggest the need for further evaluation of the effects of repetitive exposure to environmental time-varying MFs on human health."
"Results showed a decrease in the following parameters: tubular diameter and seminiferous tubules area; seminiferous epithelium height; total volume of seminiferous tubule; tubular lumen; seminiferous epithelium; and Leydig cells. On the other hand, an increase was observed in connective tissue cells and blood vessels volume. Plasma testosterone, Sertoli cells population, tubular length and gonadosomatic index did not change when exposed to EMF. Histomorphometric analysis showed that exposure to EMF can promote a delay in testicular development."
"Exposures to a modulated sinusoidal ELF-EMF were delivered by a Helmholtz configuration at a frequency of 60 Hz and 80 mG twice a day for one hour. This is accompanied by an increase in hsp70 protein levels, activation of specific kinases and upregulation of transcription factors that are generally associated with repair processes."
"Thirty years ago, Nancy Wertheimer and Ed Leeper published the first report on the association between childhood cancer and "electrical current configuration" of houses in Denver, Colorado. In 2001 the International Agency for Research on Cancer defined 50-60 Hz magnetic fields as "possibly carcinogenic to humans" because of the "limited evidence" of carcinogenicity of residential exposure relatively to childhood leukemia. With respect to health effects other than cancer, namely neurodegenerative disorders, miscarriage, subtle differences in the timing of melatonin release, altered autonomic control of the heart, and changes in the number of natural killer cells, some open questions still remain. Several authors recommended further investigation of the possible long-term effects of magnetic fields, focussing on populations experiencing high exposure levels. In this frame a research team of ISS searched for a suitable location to implement an epidemiological study aimed at a wide range of outcomes for which a priori hypotheses could be formulated. The recently published findings of this project showed an increase of primary and secondary malignant neoplasms, ischaemic disease and haematological diseases. Future studies should thus address the most exposed sectors of the population, take into account different outcomes (all neoplasms, neurodegenerative diseases, immunological disorders, specific cardiovascular effects) and follow research protocols that enable subsequent pooled analyses. A precautionary approach may provide the frame for decision making where the available resources for environmental remediation be prioritatively allocated to worst-off situations."
"In TUNEL staining (In situ terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick end labeling), germ cells showed a significantly higher apoptotic rate in exposed mice than in sham controls (P < 0.001). TUNEL-positive cells were mainly spermatogonia. In an electron microscopic study, degenerating spermatogonia showed condensation of nuclear chromatin similar to apoptosis. These results indicate that apoptosis may be induced in spermatogenic cells in mice by continuous exposure to 60 Hz MF of 14 microT."
"When phosphatidylinositol 3-kinase (PI3K) pathway was inhibited by LY294002, the increase in collagen induced by ELF-EMF exposure was accelerated, however, the increase in collagen observed by IGF-I addition was suppressed. Treatment with SB203580, an inhibitor of p38 mitogen-activated protein kinase (p38 MAPK), suppressed the increase in the collagen induced by ELF-EMF exposure, whereas IGF-I addition increased the collagen in the presence of the inhibitor.These results suggested that collagen synthesis stimulated by ELF-EMF exposure was carried out by the participation of p38 MAPK pathway, and that PI3K pathway may have the role to suppress the collagen synthesis induced by ELF-EMF exposure, and that the suppression of the PI3K pathway may allow the acceleration of the collagen synthesis."
"The cancer incidence in the teachers at this school is unusually high and is strongly associated with high frequency voltage transients, which may be a universal carcinogen, similar to ionizing radiation."
"Single exposures to ELF-EMF increases the serum values of HDL-C, the liver content of lipoperoxides and decreases total cholesterol of the liver. The mechanisms for the effects of ELF-EMF on lipid metabolism are not well understand yet, but could be associated to the nitric oxide synthase EMF-stimulation."
"RF and temporally stable 60-Hz exposures were associated with increased E1G excretion among postmenopausal women. Women with reduced nocturnal 6-OHMS excretion may represent a sensitive subgroup."
"The resonance solution also suggests that mitochondrial proton gradients may be critical to the process. The model offers an alternative explanation to the variations of Faraday's Law and the Boltzmann constant that have been employed to explain and to dismiss biological effects from weak magnetic fields."
"Magnetic field exposure was associated with decreased 6-sulfatoxymelatonin levels, but no changes in reproductive hormone levels were observed. Participants using prescription medications and anovulatory participants had more pronounced decreases in 6-sulfatoxymelatonin levels with magnetic field exposure. This study provides further evidence that exposure to magnetic fields is associated with decreased nocturnal melatonin levels, but does not support the hypothesis that such exposure results in increased urinary levels of estrogens, LH, or FSH."
"Taken together, these EMF induced reactions could lead to a higher incidence of DNA damage and therefore, to an increased risk of tumour development. While the effects on melatonin and the extension of the lifetime of radicals can explain the link between EMF exposure and the incidence of for example leukaemia, the two additional mechanisms described here specifically for mouse macrophages, can explain the possible correlation between immune cell system stimulation and EMF exposure."
"Treatment with the iron chelator deferiprone also blocked the effects of magnetic fields on brain cell DNA, suggesting the involvement of iron. Acute magnetic field exposure increased apoptosis and necrosis of brain cells in the rat. We hypothesize that exposure to a 60-Hz magnetic field initiates an iron-mediated process (e.g., the Fenton reaction) that increases free radical formation in brain cells, leading to DNA strand breaks and cell death. This hypothesis could have an important implication for the possible health effects associated with exposure to extremely low-frequency magnetic fields in the public and occupational environments."
"However, lucigenin-amplified t-butyl hydroperoxide (TBHP)-initiated brain homogenates chemiluminescence, was significantly increased in mouse exposed to 60 Hz, MF, 12 G for 3 h compared to sham exposed group. We also measured SOD activity, that plays a critical role of the antioxidant defensive system in brain. In the group exposed to 60 Hz, MF, 12 G for 3 h, brain SOD activity was significantly increased. These results suggest that 60 Hz, MF could deteriorate antioxidant defensive system by reactive oxygen species (ROS), other than superoxide radicals. Further studies are needed to identify the kind of ROS generated by the exposure to 60 Hz, MF and elucidate how MF can affect biological system in connection with oxidative stress."
"The co-exposure of cells to BP and 0.8 mT ELF-EMF for 24 h, followed by BP exposure for 48 h led to significant increases in the frequencies of MN and SCE compared to BP treatment for 72 h alone (P<0.05), but no significant difference was observed between field exposed and sham exposed control cells. The obtained results suggest that low density ELF-EMF could act as an enhancer of the initiation process of BP rather than as an initiator of mutagenic effects in human lymphocytes."
"Exposure-related reductions in 6-OHMS excretion were observed in Study 2, where daily cellular telephone use of >25 min was more prevalent. Prolonged use of cellular telephones may lead to reduced melatonin production, and elevated 60-Hz MF exposures may potentiate the effect."
"The Risk Evaluation analyzes the potential human health risks of magnetic field exposure. Specifically, this document provides an evaluation of the animal, laboratory and human evidence that shows how exposure to 50/60 Hz magnetic fields may or may not increase human health risks. The Risk Evaluation is based on the results of published research studies, with emphasis on new studies, the National Institute of Environmental Health Sciences (NIEHS) Working Group Report, and the results of the California EMF Program Studies."
"In this review, we describe the interaction of MF and biological systems, showing that preceding exposures to MF of 100 µT for 3, 5, and 7 days blocked the melatonin-induced inhibition of cAMP accumulation in a time-dependent manner, while the functions of three components, such as melatonin receptor, G protein, and adenylyl cyclase that consist of the signal transduction pathway were not affected. It still remains to be developed which theoretical chemistry explains our findings."
"These data do not indicate that EHS patients or control are affected by low-level 60 Hz magnetic field exposure. However, persons reporting EHS differed from the control subjects in baseline values of investigated physiological characteristics. Perhaps EHS patients have a rather distinctive physiological predisposition to sensitivity to physical and psychosocial environmental stressors."
"Lower nocturnal urinary 6-sulfatoxymelatonin level was associated with more hours of daylight, older age, higher body mass index, current alcohol consumption, and current use of medications classified as beta blockers, calcium channel blockers, or psychotropics. After adjustment for these factors, higher bedroom magnetic field level was associated with significantly lower urinary concentration of 6-sulfatoxymelatonin during the same night, primarily in women who used these medications and during times of the year with the fewest hours of darkness. These results suggest that exposure to nighttime residential 60-Hz magnetic fields can depress the normal nocturnal rise in melatonin."
"Cells were harvested at selected times, and enumerated without knowledge of treatment. In the melatonin study, the experiment was repeated three times, whereas in the tamoxifen study, each experiment was repeated nine times. In the melatonin study, cell numbers per dish were significantly reduced (by 16.7%) in the melatonin treated cultures after 7 days of incubation compared to control cultures, whereas in the presence of 1.2 microT(rms), 60 Hz magnetic fields, the melatonin treated cultures had the same cell populations as the control cultures. In the tamoxifen study, tamoxifen reduced the cell growth by 18.6 and 25% on days 6 and 7, respectively, in the chamber not energized, while in 1.2 microT(rms), 60 Hz fields, tamoxifen reduced the cell growth only by 8.7 and 13.1%, respectively. These results are consistent with those reported by Harland and Liburdy. A critical element of this successful replication effort was the constructive communication established and maintained with the original investigators."
"EMF itself did not induce NO generation, however, it enhanced LPS induced NO generation in vivo."
"There was a magnetic field-dependent reduction in adjusted mean nocturnal and post-work 6-OHMS levels among men working more than 2 hours per day in substation and 3-phase environments and no effect among those working 2 hours or less. No changes were observed among men working in 1-phase environments. The results suggest that circular or elliptical magnetic field polarization, or another factor linked to substations and 3-phase electricity, is associated with magnetic field induced melatonin suppression in humans."
"These data indicate that MF can increase the proliferation of human astrocytoma cells and strongly potentiate the effects of two agonists. These findings may provide a biological basis for the observed epidemiological associations between MF exposure and brain tumors."
"After a 1 mT exposure and labeling with [(33)P], sp 27 isoforms b and c were phosphorylated whereas isoform 'a' was not observed. Sps 70i, 72c, and 90 were identified by commercial sp antibodies. Likewise, polypeptides a, b, and c were verified as sp 27 isoforms by Western blotting. Statistical evaluation of sp areas and densities, determined from fluorographs by Western-blot analysis, revealed a significant increase in sps 90 and 27a after a 1 mT magnetic field exposure. The 1 mT magnetic field interacts at the cellular level to induce a variety of sp species."
"Geometric mean magnetic field exposures were not associated with 6-OHMS/cr excretion. Men in the highest quartile of temporally stable magnetic field exposure had lower 6-OHMS/cr concentrations on the second and third days compared with those in the lowest quartile. Light exposure modified the magnetic field effect. A progressive decrease in mean 6-OHMS/cr concentrations in response to temporally stable magnetic fields was observed in subjects with low workplace light exposures (predominantly office workers), whereas those with high ambient light exposure showed negligible magnetic field effects. Melatonin suppression may be useful for understanding human biologic responses to magnetic field exposures."
"Subjects exposed intermittently to the field also reported sleeping less well and feeling less rested in the morning than subjects in the other two groups. All observed effects were significant at P < or = .04 or less. The public health relevance of these results cannot be assessed as yet. Poor sleep quality, however, can have a detrimental influence on worker safety and performance, and has been associated with decrements in memory and learning processes. Additional research appears warranted."
"During the probe trial, magnetic field-exposed animals spent significantly less time in the quadrant that contained the platform, and their swim patterns were different from those of the controls. These results indicate that magnetic field exposure causes a deficit in spatial "reference" memory in the rat. Rats subjected to magnetic field exposure probably used a different behavioral strategy in learning the maze."
"Modest reductions in the mean 6-OHMS levels occurred after RCMS exposures during work. The greatest reductions occurred when RCMS exposures both at work and at home were combined; therefore the effects of temporally stable magnetic fields may be integrated over a large portion of the day. Results from this study provide evidence that temporally stable magnetic field exposures are associated with reduced nocturnal 6-OHMS excretion in humans."
"Therefore, we suggest that MFs, rather than producing biological effects by a new pathway or mechanism of interaction, exert their effect(s) by interacting with already functioning reactions or pathways. If correct, the question of an MF's mechanism of interaction refocuses on how weak fields might enhance or depress a molecular reaction in progress, rather than on finding a new transduction pathway."
"B-cells rendered BTK-deficient by targeted disruption of the btk gene did not show enhanced PLC-gamma2 activation in response to EMF exposure. Introduction of the wild-type (but not a kinase domain mutant) human btk gene into BTK-deficient B-cells restored their EMF responsiveness. Thus, BTK exerts a pivotal and mandatory function in initiation of EMF-induced signaling cascades in B-cells."
"Pretreatment with the cholinergic agonist physostigmine before magnetic field exposure reversed the field's effect on spatial learning. Data from this experiment indicate that magnetic field-induced spatial learning deficit is caused by the effect of the field on cholinergic systems."
"The results were based on the separate analysis of 870 cases of leukemia, 577 brain tumors, and 1,980 female breast cancers. We estimated the risk of leukemia among those exposed to magnetic fields of > 0.2 microtesla (microT), relative to the risk among those exposed to fields of < 0.1 microT; the odds ratio was 1.4 [95% confidence interval (CI) = 1.0-1.9]. For distance < 50 meters relative to > or = 100 meters, the relative risk was 2.0 (95% CI = 1.4-2.9). For brain tumors and female breast cancers, the odds ratios were close to unity."
"Thus, stimulation of Lyn is a proximal and mandatory step in EMF-induced activation of PKC in B-lineage lymphoid cells. Our observations prompt the hypothesis that a delicate growth regulatory balance might be altered in B-lineage lymphoid cells by EMF-induced activation of Lyn."
"Dogs that lived in homes with very high current codes had the highest risk (OR = 6.8, 95% CI 1.6-28.5). Moderate, imprecise increases in risk (odds ratios of 1.5-1.9) were found for residence in a home with a sidewalk (plumbing), backyard, or front yard magnetic field of 2.0 mG or greater, but not for indoor measurements at this level. Risk increased among dogs that spent more than 25% of the day outdoors. Laboratory and observational studies of dogs as an animal model for the effects of magnetic fields are recommended."
"In its integrated form. SV-40 DNA offers an opportunity to observe the behavior of what is in effect a viral genome within a cellular genome, with transcriptional and translational products that can be clearly distinguished from those of the host cell. Exposure of SV40-transformed human fibroblasts to a 60 Hz continuous-wave sinusoidal electromagnetic (EM) field resulted in increased levels of virally derived mRNA and protein of large T-antigen. These findings provide evidence that a foreign DNA integrated into cells can be affected by EM fields under conditions known to cause increased transcripts from endogenous cellular genes."
"Electrical workers in the aggregate showed little evidence of increased risk, with the possible exception of an increase in elevated MMPI depression scores among short-term workers. Data on electricians yielded indications of increased risk for several markers of depression. Despite the limited number of electrical workers, uncertainty regarding exposure, and our inability to address other workplace exposures, these results suggest that electrical workers in general are not at increased risk for depression. However, our results encourage further evaluation of depression among electricians."
"These findings support the above ST hypothesis and provide experimental evidence for a general biological framework for understanding magnetic field interactions with the cell through signal transduction. In addition, these findings indicate that magnetic fields can act as a co-stimulus at suboptimal levels of mitogen; pronounced physiological changes in lymphocytes such as calcium influx and c-MYC mRNA induction were not triggered by a weak mitogenic signal unless accompanied by a magnetic field. Magnetic fields, thus, have the ability to potentiate or amplify cell signaling."
"The data demonstrates that long-term exposure of DMBA-treated female rats to an alternating MF of low flux density promotes the growth and increases the incidence of mammary tumors, thus strongly indicating that MF exposure exerts tumor-promoting and/or copromoting effects."
"Exposure conditions vary greatly among different end points measured, making comparisons and conclusions among experiments difficult. Although most of the available evidence does not suggest that electric and/or magnetic fields cause DNA damage, the existence of some positive findings and limitations in the set of studies carried out suggest a need for additional work."
"Time-dependent and cell density-dependent changes in the transcription of c-fos, c-jun, c-myc and protein kinase C (beta-form) have been observed and quantitated. Additionally, changes in transcript levels, assessed by slot-blot analysis, have been found to parallel the changes in gene transcription. These data suggest an important role for magnetic field exposure in altering cellular processes."
"Measured magnetic fields under low power use conditions had a modest association with cancer incidence; a cutoff score of 2.0 milligauss resulted in an odds ratio of 1.4 (95% confidence interval (CI) = 0.6-2.9) for total cancers and somewhat larger odds ratios (ORs) for leukemias (OR = 1.9), lymphomas (OR = 2.2), and soft tissue sarcomas (OR = 3.3). Neither magnetic fields (OR = 1.0) nor electric fields (OR = 0.9) under high power use conditions were related to total cancers. Wire codes associated with higher magnetic fields were more common among case than control homes. The odds ratio to contrast very high and high to very low, low, and buried wire codes was 1.5 (95% CI = 1.0-2.3) for total cases, with consistency across cancer subgroups except for brain cancer (OR = 2.0) and lymphomas (OR = 0.8). Contrasts of very high to buried wire code homes produced larger, less precise odds ratios of 2.3 for total cases, 2.9 for leukemias, and 3.3 for lymphomas."