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At least 253 records · Page 14Linked to original sources
PubMed2005

Urinary 6-sulfatoxymelatonin excretion in humans during domestic exposure to 50 hertz electromagnetic fields.

OBJECTIVES: Exposure to extremely low frequency electromagnetic fields (ELF-EMF) has been suggested to suppress melatonin secretion, which might result in higher cancer risks because of its missing oncostatic action. We investigated the effects of residential exposure to ELF-EMF on the excretion of urinary 6-sulfatoxymelatonin (6-OHMS), the major melatonin metabolite, as an indicator of nocturnal melatonin secretion. METHODS: 6-OHMS was measured in two spot urine samples, collected at 22.00 h and 08.00 h, in 29 men and 22 women. Spot ELF-EMF measurements were conducted at the centre and the four angles of the living room, the bedroom, and the kitchen of study subjects at low current configuration (all lights and appliances turned off), and they were repeated immediately at high current configuration (all lights and appliances turned on). RESULTS: Risk of a reduced 6-OMHS nocturnal secretion was elevated for daily alcohol intake (OR = 6.4; 95%C.I. 1.4,33.1), and body mass index (BMI) above the median (OR = 2.2; 95%C.I. 0.5,9.6). Risk of disrupted rhythm of 6-OHMS excretion was moderately elevated for domestic ELF-EMF exposure above the upper tertile at low current configuration (OR = 2.6; 95%C.I. 0.4,15.7). CONCLUSION: Alcohol consumption, BMI, and gender seem to affect nocturnal melatonin secretion, while an effect of residential exposure to ELF-EMF is uncertain. Future studies should properly account for the effect of such variables, when addressing the hypothesis of disturbances in melatonin secretion as a plausible explanation for the reported excess risk of several tumoral diseases associated with low level ELF-EMF exposure.

Adult↗
PubMedDate not supplied

Subchronic effects on leukocyte-endothelial interactions in mice by whole body exposure to extremely low frequency electromagnetic fields.

Abstract. In the present study, we measured and quantified changes in leukocyte behavior in the subcutaneous microcirculation in vivo and examined serum cytokine levels in vitro while mice were exposed to continuous 50 Hz electromagnetic fields for 17 days. Mice were exposed to 50 Hz sinusoidal electromagnetic fields at magnetic densities of 0.3, 1.0 and 3.0 mT. The intramicrovascular behavior of leukocytes was evaluated by fluorescence microscopy using a dorsal skinfold chamber technique. Significantly increased endothelial-adhering leukocytes were observed only in the 3.0 mT exposure group, but no changes were detected in serum TNF-alpha and IL-1beta levels. Subsequently, long-term continuous whole body exposure to 50 Hz electromagnetic fields elicited leukocyte-endothelium interactions, however, this effect does not appear to be controlled by cytokine levels.

Animals↗
PubMed2003

Effects of electromagnetic fields on the immune systems of occupationally exposed humans and mice.

The authors examined immunological disorders in 6 individuals who had been exposed occupationally to environmental electromagnetic fields. Comparable effects on mice exposed in a similar environment were also investigated. The human subjects had worked 8 hr/day for 5 yr in a laboratory located above electrical transformers and high-tension cables, and in which there were low-frequency electromagnetic fields of 0.2-6.6 microtesla (microT). The 6 control subjects (matched for socioeconomic parameters, sex, and age) had worked away from the immediate vicinity of transformers and high-tension cables. The authors found statistically significantly lower total lymphocyte, CD4, and CD3 counts, and significantly increased natural killer (NK) cells, in exposed subjects vs. controls. Six months after exposure had ceased, total lymphocyte counts had increased, as had CD4, CD3, and CD19 counts (+13%, +28%, +22%, and +17%, respectively), and NK cell counts were decreased by 26% (not significant) in the same human subjects. In the second part of this study, 12 Swiss male mice housed in cages were exposed in the same room in which the human subjects had been exposed (i.e., 5-microT, 50-Hz magnetic field) for 109 days; 12 additional mice were used as unexposed controls. The total lymphocyte, leukocyte, polymorphonuclear neutrophil, CD4, and NK counts of the exposed mice at 109 days were significantly lower than those of controls. In addition, plasma glucose levels (at 30 days) and amylase activity (at 109 days) were significantly lower, whereas plasma sodium and chloride levels were significantly elevated at 109 days. Results from this study suggest that chronic exposure to a 0.2-6.6-microT magnetic field can lead to decreased immunological parameters (total lymphocytes and CD4 counts) in both humans and mice. The increase in some values once exposure was terminated suggests a causal relationship with exposure to electromagnetic fields, as do the changes in mice, particularly the changes in total lymphocyte and CD4 counts.

Adult↗
PubMed1999

Electromagnetic fields in combination with elevated temperatures affect embryogenesis of Drosophila.

The effect of electromagnetic fields (50 Hz, 100 microT magnetic flux density) on Drosophila embryogenesis was tested under conditions of mild thermal stress (temperatures between 34 and 37 degrees C). When exposed to these stressor(s) for 30 min during early embryogenesis those embryos which were subjected to both electromagnetic fields and elevated temperature (costress) showed pattern anomalies more frequently than embryos subjected to thermal stress alone. Furthermore, under costress conditions development was considerably delayed in three different strains tested. The use of transgenic strains with a lacZ reporter being expressed in segmental patterns facilitated the identification and quantification of the pattern anomalies.

Animals↗
PubMed1993

Beneficial effects of electromagnetic fields.

Selective control of cell function by applying specifically configured, weak, time-varying magnetic fields has added a new, exciting dimension to biology and medicine. Field parameters for therapeutic, pulsed electromagnetic field (PEMFs) were designed to induce voltages similar to those produced, normally, during dynamic mechanical deformation of connective tissues. As a result, a wide variety of challenging musculoskeletal disorders have been treated successfully over the past two decades. More than a quarter million patients with chronically ununited fractures have benefitted, worldwide, from this surgically non-invasive method, without risk, discomfort, or the high costs of operative repair. Many of the athermal bioresponses, at the cellular and subcellular levels, have been identified and found appropriate to correct or modify the pathologic processes for which PEMFs have been used. Not only is efficacy supported by these basic studies but by a number of double-blind trials. As understanding of mechanisms expands, specific requirements for field energetics are being defined and the range of treatable ills broadened. These include nerve regeneration, wound healing, graft behavior, diabetes, and myocardial and cerebral ischemia (heart attack and stroke), among other conditions. Preliminary data even suggest possible benefits in controlling malignancy.

Animals↗
PubMed1985

Weak 50-Hz electromagnetic fields activate rat open field behavior.

Rats were tested in an open field after previous exposure to a weak, 50-Hz electromagnetic field of the same order of magnitude as the earth's magnetic field. Animals exposed to the artificial field at the beginning of the light phase showed 40% more rearing activity than controls, together with a slight increase in ambulation and a tendency towards less defecation and a shortened rearing latency. A replication experiment yielded the same results. Animals exposed at the beginning of the dark phase manifested no significant changes in open field activity. The results show that weak electromagnetic stimuli can modify some behavioral responses, and that these responses are sensitive to circadian phase.

Animals↗
PubMed1985

Electromagnetic fields in biological studies.

For biological or cellular experiments using electromagnetic fields, it is essential that the parameters defining the field be carefully specified if the results are to be meaningful and are to be compared with the same experiment conducted in a different laboratory. The interaction of living systems with electric and magnetic fields can come only through forces exerted on the charges on the system. If the charges are stationary, the only origin of the force is the electric field. This electric field may be established by charge distributions, as in "capacitive plate" experiments, or by time-varying magnetic fields. A geometry commonly used to produce time-varying magnetic fields consists of a pair of coaxial coils, each of equal radius and separated by a distance often equal to the radius. The electric field induced by a varying current in such a pair of coils varies both in space and in time. The electric field strength is zero on the axis of symmetry, and increases to a maximum near the radius of the coils. The strength is proportional to the time rate of change of the current in the coil, which depends not only on the amplitude and shape of the voltage pulse applied to the coil but also on the resistance and inductance of the coil. The purpose of this article is to describe how these important physical parameters may be determined for both geometries.

Animals↗
PubMed1985

Comments on the use of electromagnetic fields in biological studies.

For biological or cellular experiments using electromagnetic fields it is essential that the parameters defining the field be accurately specified if the results are to be meaningful and are to be compared with the same experiment conducted in a different laboratory. The interaction of living systems with electric and magnetic fields can come only through forces exerted on the charges on the system. If the charges are stationary the only origin of the force is the electric field. The electric field may be established by charge distributions, as in "capacitative plate" experiments, or by time-varying magnetic fields consists of a pair of coaxial coils each of equal radius and separated by a distance about equal to the radius. The electric field induced by a varying current in such a pair of coils varies both in space and in time. The field is always zero on the axis of symmetry, and increases to a maximum near the radius of the coils. The strength is proportional to the time-rat-of-change of the current in the coil, which depends not only on the amplitude and shape of the voltage pulse applied to the coil but also on the resistance and inductance of the coil. The purpose of this note is to describe how the important physical parameters may be determined.

Biological Transport↗
PubMed1990

[The effect of a pulsed electromagnetic field on ocular hydrodynamics in open-angle glaucoma].

The influence of pulse electromagnetic field on the hydrodynamics of the eye in open-angle glaucoma has been studied using the method and the device suggested at the Filatov Institute. The characteristics of the action were: impulse frequency--50 Hz, duration--0.02 sec., pulse form--rectangular, rate of pulse rise--4/10(-4) sec., rate of magnetic induction rise--2/10(-4) mT/sec., amplitude value of magnetic induction at the pulse level--8.0-8.5 mT, duration of the procedure--7 min. Ten session in a total. Observations over 150 patients (283 eyes) with latent, initial and advanced glaucoma have shown that the usage of pulse electromagnetic field exerts influence on the hydrodynamics of the eye in open-angle glaucoma; stimulates the rise of aqueous outflow and production, the reduction of the Becker's coefficient. At the latent stage of the disease, normalization of outflow was recorded in 25% of cases, at the initial and advanced stages--in 17.8% and 16.0% of cases, respectively. The investigations carried out allow to recommend the mentioned method for a complex treatment of open-angle glaucoma.

Aged↗
PubMed1988

Electromagnetic field focusing system in the treatment of brain tumors.

The electromagnetic field focusing (EFF) probe, which is based on the principle of eddy current convergence, produces intense pinpoint heat at its point of contact with tissue. This allows cutting and vaporization of tissue and coagulation of vessels. The present experiments were conducted to study heat distribution to the surrounding tissue in brain and phantom and the effect on the brain of vaporization of intracerebral tumors in 19 rabbits. The follow-up period was as long as 47 days. The heating pattern showed a rise of temperature up to 250 degrees C at the probe tip, with minimal or no temperature increase at 2 mm and beyond. Minimal or no change was noted in the surrounding brain after tumor vaporization, indicating that this system would be safe in the vaporization of brain tumors in clinical neurosurgery.

Animals↗
PubMed2001

Comparison of electromagnetic field stimulation on the healing of small and large intestinal anastomoses.

PURPOSE: Magnetic fields have been shown to affect biologic processes. Accordingly, an experimental study was designed to investigate the effect of electromagnetic field stimulation on intestinal healing and to compare small and large intestinal anastomoses. METHODS: An ileal or a colonic anastomosis was constructed in rats. Beginning the day after surgery, randomly assigned groups were exposed to sinusoidal electromagnetic field stimulation of 10.76-mT intensity and 50-Hz frequency, with 2-hour-on/10-hour-off cycles. After seven days, intestinal anastomoses were assessed for hydroxyproline content and breaking strength. Statistical comparison between each experimental and control group yielded significance (P < 0.05) in all cases. RESULTS: Hydroxyproline content increased significantly in ileum from 1.650 +/- 0.11 (mean +/- standard error of the mean) to 2.036 +/- 0.11 microg/mg (P = 0.0249) and in colon from 1.526 +/- 0.11 to 1.922 +/- 0.11 microg/mg (P = 0.0135). Breaking strength also increased significantly in ileum from 0.213 +/- 0.01 to 0.255 +/- 0.01 MPa (P = 0.001) and in colon from 0.227 +/- 0.01 to 0.270 +/- 0.01 MPa (P = 0.006). CONCLUSIONS: Electromagnetic field stimulation provided a significant gain in anastomotic healing in both small and large intestine. There were no apparent differences detected between the healing of small and large intestinal anastomoses except for slight differences in the time sequences of events and magnitude. The study demonstrated a significant increase in both biochemical and mechanical parameters. Additional investigations are needed to determine optimal conditions and promote selective biologic responses.

Anastomosis, Surgical↗
PubMed1997

No short-term effects of high-frequency electromagnetic fields on the mammalian pineal gland.

There is ample experimental evidence that changes of earth-strength static magnetic fields, pulsed magnetic fields, or alternating electric fields (60 Hz) depress the nocturnally enhanced melatonin synthesis of the pineal gland of certain mammals. No data on the effects of high-frequency electromagnetic fields on melatonin synthesis is available. In the present study, exposure to 900 MHz electromagnetic fields [0.1 to 0.6 mW/cm2, approximately 0.06 to 0.36 W/kg specific absorption rate (SAR) in rats and 0.04 W/kg in Djungarian hamsters; both continuous and/or pulsed at 217 Hz, for 15 min to 6 h] at day or night had no notable short-term effect on pineal melatonin synthesis in male and female Sprague-Dawley rats and Djungarian hamsters. Pineal synaptic ribbon profile numbers (studied in rats only) were likewise not affected. The 900 MHz electromagnetic fields, unpulsed or pulsed at 217 Hz, as applied in the present study, have no short-term effect on the mammalian pineal gland.

Animals↗
PubMed1998

No effects of pulsed high-frequency electromagnetic fields on heart rate variability during human sleep.

The influence of pulsed high-frequency electromagnetic fields emitted by digital mobile radio telephones on heart rate during sleep in healthy humans was investigated. Beside mean RR interval and total variability of RR intervals based on calculation of the standard deviation, heart rate variability was assessed in the frequency domain by spectral power analysis providing information about the balance between the two branches of the autonomic nervous system. For most parameters, significant differences between different sleep stages were found. In particular, slow-wave sleep was characterized by a low ratio of low- and high-frequency components, indicating a predominance of the parasympathetic over the sympathetic tone. In contrast, during REM sleep the autonomic balance was shifted in favor of the sympathetic activity. For all heart rate parameters, no significant effects were detected under exposure to the field compared to placebo condition. Thus, under the given experimental conditions, autonomic control of heart rate was not affected by weak-pulsed high-frequency electromagnetic fields.

Adult↗
PubMed1997

Extremely high frequency electromagnetic fields at low power density do not affect the division of exponential phase Saccharomyces cerevisiae cells.

Exponentially growing cells of the yeast Saccharomyces cerevisiae were exposed to electromagnetic fields in the frequency range from 41.682 GHz to 41.710 GHz in 2 MHz increments at low power densities (0.5 microW/cm2 and 50 microW/cm2) to observe possible nonthermal effects on the division of this microorganism. The electronic setup was carefully designed and tested to allow precise determination and stability of the electromagnetic field parameters as well as to minimize possible effects of external sources. Two identical test chambers were constructed in one exposure system to perform concurrent control and test experiments at every frequency step under well-controlled exposure conditions. Division of cells was assessed via time-lapse photography. Control experiments showed that the cells were dividing at submaximal rates, ensuring the possibility of observing either an increase or a decrease of the division rate. The data from several independent series of exposure experiments and from control experiments show no consistently significant differences exposed and unexposed cells. This is in contrast to previous studies claiming nonthermal effects of electromagnetic fields in this frequency range on the division of S. cerevisiae cells. Possible reasons for this difference are discussed.

Cell Division↗
PubMed1990

A randomized double-blind prospective study of the efficacy of pulsed electromagnetic fields for interbody lumbar fusions.

A randomized double-blind prospective study of pulsed electromagnetic fields for lumbar interbody fusions was performed on 195 subjects. There were 98 subjects in the active group and 97 subjects in the placebo group. A brace containing equipment to induce an electromagnetic field was applied to patients undergoing interbody fusion in the active group, and a sham brace was used in the control group. In the active group there was a 92% success rate, while the control group had a 65% success rate (P greater than 0.005). The effectiveness of bone graft stimulation with the device is thus established.

Animals↗
PubMed1995

Analgesic properties of electromagnetic field therapy in patients with chronic pelvic pain.

AIM: Demonstration of analgesic effects of electromagnetic field treatment in cases of chronic refractory pelvic pain. STUDY DESIGN: Prospective non-controlled trial, 64 women complaining about pelvic pain of at least 6 months duration, resistant to standard therapies, submitted to electromagnetic field applications on both iliac regions by Thelf Systems apparatus by two applications daily lasting 2 hours each for 20-40 days. Control visit after 3 months. RESULTS: Complete subsidence of pain in 39 cases (61%), in 15 patients (23%) relief during treatment, then mild endopelvic tension after a 3-month control; in 10 cases (16%) symptoms reduced only during application hours, unchanged at follow-up. Outcome of treatment appears to be independent of pre-existent psychosocial variables. CONCLUSION: Magnetic therapy shows a real analgesic effect on pelvic pain, and seems to contribute to resolution of complex interactions between somatic nociceptive stimuli and psychosocial implications affecting pain perception in these patients.

Adult↗
PubMed1996

Teratogen update: electromagnetic fields.

Public concern is increasing about the potential health effects of extremely low frequency (ELF) electromagnetic fields (EMFs) naturally present or generated by electrical appliances and those of very low frequency (VLF) fields, like those generated by video display terminals (VDTs). There are arguments in favour of EMFs being biologically active but no mechanism has been identified that explains the link between EMFs and bioeffects. More than 50 studies on exposures of animals to EMFs have been performed within the last few years. Although there were a few statistically significant effects in the studies reviewed, no replicable results were found among laboratories. The extent of effects observed, if any, was always low, and deserves further investigation before relevance to humans can be considered. Human data reviewed concern the potential reproductive effects (mainly) spontaneous abortions, low birthweight, and congenital malformations) of exposure to various sources of EMFs: maternal residence, heated waterbeds, electric blankets, and ceiling heating coils, occupational exposure (mainly video display terminals), and magnetic resonance imaging. The totality of the evidence that is thus far available provides no convincing evidence to indicate that low frequency EMFs of the sort that might be met in occupational or daily life exposures does any harm to the human reproductive process. It is suggested that those counseling pregnant women follow the guidelines established by WHO in agreement with the International Non-ionizing Radiation Committee. This group does not consider that the results of published studies provide a basis for restricting human exposure to electromagnetic fields and radiation.

Animals↗