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PubMed2002

[Effects of extremely low frequency electromagnetic field and its combination with lead on the antioxidant system in mouse].

OBJECTIVE: To study the effects of extremely low frequency electromagnetic field(ELF EMF) and its combination with lead on the antioxidant system in mouse brain and liver tissues. METHOD: Mice were exposed to a 50 Hz sinusoidal 0.2 mT or 6.0 mT EMF for 2 weeks. At the same time, some groups were exposed to lead(50 mg/kg). After the exposure, the antioxidant system and cell membrane fluidity in brain and liver were measured. RESULTS: Malondiadehyde(MDA) content in brain and liver increased from the control levels of (1.33 +/- 0.12) and (3.95 +/- 0.21) nmol/mg pro to (1.35 +/- 0.09) and (6.15 +/- 0.28) nmol/mg pro respectively following 0.2 mT exposure, and to (3.98 +/- 0.10) and (6.50 +/- 0.79) nmol/mg pro respectively following 6.0 mT exposure. Total antioxidant capability(T-AOC) in brain and liver decreased from the control levels of (4.39 +/- 0.48) and (2.45 +/- 0.21) U/mg pro to (3.99 +/- 0.39) and (1.92 +/- 0.32) U/mg pro respectively following 0.2 mT, and to (3.12 +/- 0.37) and (1.57 +/- 0.14) U/mg pro respectively following 6.0 mT. GSH content decreased only in liver tissue from the control level of (194.60 +/- 20.93) mg/g pro to (189.24 +/- 5.61) mg/g pro(0.2 mT) and (153.04 +/- 1.18) mg/g pro(6.0 mT). Cellular membrane fluidity decreased from the control levels of (1.396 +/- 0.040) and (2.899 +/- 0.552) to (1.224 +/- 0.190) and (1.894 +/- 0.0761) (0.2 mT), (1.159 +/- 0.179) and (1.516 +/- 0.204)(6.0 mT) respectively. Compared with single EMF exposure(6.0 mT), EMF combined with lead exposure induced remarkable increase in MDA, GSH content and T-AOC and decrease in cell membrane fluidity both in the brain and liver, and increase in SOD activity only in liver. CONCLUSION: ELF EMF might alter the metabolism of free radicals, decrease anti-oxidant capability and enhance lipid peroxidation. The combination of EMF with lead showed synergic effects on lipid peroxidation.

Animals↗
PubMed1996

Electromagnetic field induced changes in lipid second messengers.

Initial studies with a human hematopoietic cell line, TF-1, suggest multifarious effects of electromagnetic fields on lipid signal transduction. We have examined the effects of pulsed magnetic fields (2 T, 84 microseconds zero-to-peak haversine, 91 V/m induced electric field) on the cell cycle by flow cytometry. A 31% increase of cells in the G1 phase occurred concurrently with a 35% decrease of cells in S-phase, which suggests that doses of 30 or 40 pulses have an anti-proliferative effect. Changes in the lipid second messengers, diacylglycerol (DAG) and phosphatidic acid (PA) with stimuli of 2 T intensity were also dependent on the number of pulses. DAG production doubled with 30 pulses and tripled with 40 pulses, and PA levels were reduced to one third and one tenth of the original levels. Phospholipase D (PLD) up-regulation was assessed directly by the capacity of PLD to catalyze transphosphatidylation in the presence of alcohol. [3H]Phosphatidylethanol formed rapidly and continued to increase with concomitant decreases in [3H]PA and parallel generation of [3H]DAG. Propranolol, an inhibitor of PA phosphohydrolase, inhibited the formation of DAG in a dose-dependent manner with a marked increase in PA production. Examination of the kinetics of formation of [3H]choline and [3H]phosphocholine at different times after stimulation showed a rapid and consistent increase in [3H]choline, whereas [3H]phosphocholine increase was evident only 60 min after stimulation. Magnetic exposure also caused a shift in some molecular species patterns of DAG and PA which could be correlated with phosphatidylinositol, phosphatidylethanolamine and phosphatidylcholine molecular species decreases. Therefore, we propose that the PC-PLC pathway may be temporarily inactivated for a short period of time by exposure to pulsed stimuli, and the PC-PLD pathway is up-regulated based on: (1) cellular release of [3H]choline; (2) rapid intracellular formation of [3H]PA followed by [3H]DAG; (3)active transphosphatidylation; and (4) blockade of DAG formation by propranolol.

Cell Line↗
PubMed2004

[Hygienic assessment of sources of electromagnetic fields using revised and new standards of maximum admissible intensities].

In 2001, the legal regulation on maximum admissible intensities (MAI) of electromagnetic fields (EMF) in the frequency range of 0-300 GHz was amended. In the existing regulation, the ranges for frequencies between 0 and 50 Hz and between 50 Hz and 1 kHz were not defined, and for the frequency of 50 Hz there were no regulations for the electric component. The amended regulation expands the obligation to measure and assess the magnetic component up to 3 GHz (formerly to 10 MHz only) and moderates the admissible level for extremities at the frequency below 800 kHz (magnetic component). In addition, the MAI values are thoroughly verified in the whole range of standardized frequencies. Formally, all kinds of power supplied equipment are the source of EMF. In practice, the measurement of all equipment and installations is not feasible or justified. According to the Database by the Chief Sanitary Inspector, the number of EMF sources recorded by the sanitary inspection in 2002 exceeded 60 thousand. Therefore, it was found advisable to analyze the results obtained from the studies of occupational exposure to EMF after the introduction of new MAI'2001 to select equipment and to find out whether equipment and installations generating EMF corresponding at most with protective zone needs to be controlled. The analysis covered 9 thousand of equipment and installations of various types (data collected by the Central Database on EMF sources and our own data), in particular EMF sources: strong EMF with endangered protective zone and non-identified levels of generated EMF; weak EMF but responsible for chronic exposure; and EMF sources occurring in large quantities in places where people work or have to stay longer (e.g., hospitals, treatment rooms, production halls). The analysis facilitated the hygienic evaluation of the equipment and installations according to MAI'2001. In all, 49% of equipment were found not to be the source of EMF with values from protective zones, and thus it is obvious that their control is not justified as exposure does not occur or in case of occupational exposure it can be neglected. The authors present a long list of equipment and installations with the maximum levels of generated EMF. The level of generated EMF was assessed according to the criterion of protective zones: intermediate, hazardous and dangerous.

Electromagnetic Fields↗
PubMed1987

Effects of low-intensity pulsed electromagnetic fields on the early development of sea urchins.

The effects of weak electromagnetic signals on the early development of the sea urchin Paracentrotus lividus have been studied. The duration and repetition of the pulses were similar to those used for bone healing in clinical practice. A sequence of pulses, applied for a time ranging from 2 to 4 h, accelerates the cleavages of sea urchin embryo cells. This effect can be quantitatively assessed by determining the time shifts induced by the applied electromagnetic field on the completion of the first and second cleavages in a population of fertilized eggs. The exposed embryos were allowed to develop up to the pluteus stage, showing no abnormalities.

Animals↗
PubMed2002

Spectral properties of fluctuating electromagnetic fields in a plane cavity: implication for nanoscale physics.

Spectral power densities of fluctuating electromagnetic fields and their spatial derivatives of all orders in any point of a transparent plane gap between two media described by different complex permittivities and by different temperatures were derived on a basis of generalized Kirchhoff's law. Electromagnetic losses into the two absorbing media induced by a field of a point dipole or of point multipolelike origins situated in any place of interest at the transparent gap were determined. The corresponding electrodynamical regular Green problem for a point dipole and for point multipoles of any orders constituted by the point dipole was solved. We demonstrate ways to obtain different asymptotic cases following from our general solution including the problem for a half space, Planck's formula for black body radiation, the van der Waals forces for solids kept at different temperatures, and contributions from propagating and evanescent waves. Expressions for electromagnetic loss of a point multipole of any order in selected geometry of the problem were derived and, as an important limiting case related to problems of near field microscopy, when the multipole is situated over a half space.

Journal Article↗
PubMed1996

MRI electromagnetic field penetration in cylindrical objects.

Magnetic Resonance Imaging information depends on the knowledge of the behavior of the transverse, radio frequency (RF) electromagnetic fields inside biological objects. Here we present exact results for the RF vector potential field inside and outside a cylindrical object that mimics the human body. These results are obtained by solving Maxwell Equations with appropriate boundary conditions, and take into consideration the object conductivity and dielectric constant and the presence of a cylindrical RF uniform-current-carrying coil. A computer code that evaluates RF magnetic field phase and magnitude is presented for two cases of interest: for a longitudinal and for a phi-directed current. Each of those cases is studied in free space and in the presence of a metallic shielding. The symbolic code will be of use for order-of-magnitude calculations in the clinical world and, for pedagogical uses in medical imaging courses.

Electric Conductivity↗
PubMed1991

[The biological activity of a decameter-range electromagnetic field with a frequency of 24 MHz].

A study of behavioural reactions indicates that the effect of 24 MHz frequencies of the electromagnetic field results in changes of the ratio of excitatory and inhibitory processes in the nervous system of white rats with prevalence of inhibitory processes. By the 90-th day of effect of the above factor all changes returned to the initial level. This indicates stability of the adaptative reactions of the integrative level of the nervous system to the acting factor.

Animals↗
PubMed1999

Nerves in a human body exposed to low-frequency electromagnetic fields.

Following a summarizing introduction in which the background research is reviewed and referenced, a detailed description is given of the properties of the elongated cell that constitutes a nerve axon. The functioning of the cell membrane is reviewed with reference to the transmission of a frequency-modulated signal. The need for successive regeneration by means of action potentials is described. Propagation within both myelinated and unmyelinated membranes is discussed. Currents and electric fields induced in the organs of the human body by external electric and magnetic fields are introduced and their determination reviewed. The interaction between these currents and electric fields and those involved in the propagation of a signal along a nerve axon is analyzed. It is shown that incident 60-Hz electric fields near high-voltage transmission lines do not induce large enough currents and fields in a nerve axon in the leg to disrupt a propagating signal. Scaling with respect to frequency and size is discussed. Surface sensations due to exposure to electric fields in the 5-15-kV/m range are analyzed. It is concluded that exposure to the electromagnetic field of a 60-Hz high-voltage transmission line or a 10-30-kHz high-power transmitting antenna should have no observable effect on the normal functioning of nerves.

Action Potentials↗
PubMed1990

Acute leukaemia in workers exposed to electromagnetic fields.

Results from a French case-control study of acute leukaemia and occupational exposure for the risk associated with exposure to electromagnetic fields (EMF) are reported. There were 185 cases and 513 controls. A significantly increased risk of acute leukaemia was observed for exposure to EMF other than that from arc welding (odds ratio = 4.04, 95% CI 1.26-12.88) which persisted after adjustment for possible confounding exposures. This study supports the hypothesis that workers exposed to some EMF have an increased risk of leukaemia.

Acute Disease↗
PubMed2005

Nanophotonic crescent moon structures with sharp edge for ultrasensitive biomolecular detection by local electromagnetic field enhancement effect.

We present novel gold nanophotonic crescent moon structures with a sub-10 nm sharp edge, which can enhance local electromagnetic field at the edge area. The formation of unconventional nanophotonic crescent moon structure is accomplished by using a sacrificial nanosphere template and conventional thin film deposition method, which allows an effective batch nanofabrication and precise controls of nanostructure shapes. Unique multiple scattering peaks are observed in a single gold nanocrescent moon with dark-field white light illumination. A 785 nm near-infrared (NIR) diode laser was used as the excitation source to induce the amplified scattering field on the sharp edge of the single gold nanocrescent moon. The Raman scattering spectrum of Rhodamine 6G molecules adsorbed on the single gold nanocrescent moon are characterized, and the Raman enhancement factor of single gold nanocrescent moon is estimated larger than 10(10), which suggests the potential applications of gold nanocrescent moons in ultrasensitive biomolecular detection and cellular imaging using surface enhanced Raman spectroscopy.

Electromagnetic Fields↗
PubMed2006

The "Mainzer EMF-Wachhund": results from a watchdog project on self-reported health complaints attributed to exposure to electromagnetic fields.

The "Mainzer EMF-Wachhund," a watchdog project, offered a system of self-notification of health complaints attributed to exposures to electromagnetic fields (EMFs) to a population of a part of Germany with about 4 million inhabitants. By using a self-administered questionnaire, which was provided online and for download from the Internet, 192 persons reported such health complaints in the period from October 2003 to March 2005. Of these, 56% classified themselves as electromagnetic hypersensitive (EH). Predictors of this self classification were being affected by all kinds of EMF rather than single EMF sources and being female. On average, EH subjects reported a high degree of suffering, 77% of whom had already sought advice from physicians. An Internet-based standardized questionnaire is an economic way of offering affected persons a direct link to scientific institutions to establish contact. However, the study base obtained by such an approach is not representative to estimate a population-based prevalence. As a large number of subjects did not classify themselves as EH and reported very specific links between exposure and symptoms, they may provide a very distinct and interesting group for future research.

Adolescent↗
PubMedDate not supplied

[Electromagnetic fields of millimeter range: effect on the structure and functional properties of erythrocyte membranes].

The effect of coherent and non-coherent electromagnetic fields of millimetre range on biophysical and biochemical indices of blood erythrocytes and plasma of the animals totally exposed to radiation at various periods of observation (day 1, 5, 10) was studied. The following structure-functional shifts were revealed: deviations in the content of separate phospholipid fractions of erythrocyte membranes, the changes of lipid peroxidation products in erythrocyte membranes and blood plasma of the irradiated animals, statistically significant increase of K ions out-flow from the erythrocytes, as well as the alteration of the value of membrane potential of erythrocytes.

Animals↗
PubMed2000

Electromagnetic fields enhance the stress response at elevated temperatures in the nematode Caenorhabditis elegans.

We have studied the effect of extremely low frequency electromagnetic fields (ELF-EMF) in the presence of a second stressor (mild heat shock) on the expression of a lacZ reporter gene under the control of hsp16 or hsp70 promoters in two transgenic strains of C. elegans. The expression of the reporter gene was studied by scoring animals with induced beta-galactosidase activity after staining in toto or by biochemical quantitation of the enzyme activity, respectively. In our experimental setup we were able to expose the animals to 50 Hz magnetic flux density of 0-150 microT and at the same time control temperature with high precision (+/-0.1 degrees C). Experimental conditions were defined for which EMF strongly enhances the expression of the reporter gene.

Animals↗
PubMedDate not supplied

[Impulse low-intensity electromagnetic field in the treatment of adolescents with essential arterial hypertension].

Effectiveness of different regimes of a course exposure to impulse low-intensity electromagnetic field (Infita unit) was studied in 69 adolescents with essential hypertension. A ten-day course of single 9 min procedures with 30 Hz field produced better antihypertensive effects than the regime used in the adults. This treatment provided improvement in bioelectric activity of the brain, mental state, central hemodynamics.

Adolescent↗
PubMed2004

Reversal of delayed union of anterior cervical fusion treated with pulsed electromagnetic field stimulation: case report.

We present a case report of anterior cervical fusion non-union that was successfully treated with pulsed electromagnetic field (PEMF) stimulation. In this case, a C6-C7 nonunion was identified clinically and radiographically 1 year after surgery. Imaging revealed nonunion with partial resorption of the bone graft compared with imaging studies performed 8 months earlier. The patient wore a PEMF stimulation device for 3 h/d for 10 months. After 3 months of treatment, the patient's symptoms were resolved. X-rays obtained after 15 weeks of stimulation showed improvement in bone fusion, and x-rays obtained at 31 weeks after stimulation showed even bone density around the C7 screws. The patient remained symptom-free 13 months after the termination of PEMF stimulation at last assessment. PEMF stimulation demonstrated its clinical potential in healing established nonunion of anterior cervical spine fusion. Its use is noninvasive and can be considered an alternative to surgical intervention in selected patients.

Adult↗
PubMed2002

Effects of the electromagnetic field of mobile telephones on hearing.

The widespread use of mobile telephones has given rise to concern about the potential influences of electromagnetic fields (EMFs) on human health. Anatomically, the ear is in close proximity to the mobile telephone during use. Hearing loss due to mobile telephone use has not been described in the medical literature; however, if there is a subtle cochlear involvement, it might be detected by means of changes in evoked otoacoustic emissions (OAEs). Thirty volunteers with normal hearing were exposed to mobile telephone EMFs for 10 min and evoked OAEs were measured before and after exposure. No measurable change in evoked OAEs was detected and none of the subjects reported a deterioration in hearing level. To the best of our knowledge, this is the first study on the effects of EMFs emitted by mobile telephones on hearing. It was concluded that a 10-min exposure to the EMF emitted from a mobile telephone had no effect on hearing, at least at outer ear, middle ear and cochlear levels.

Adult↗
PubMedDate not supplied

[Exposure to low-frequency electromagnetic fields and pregnancy outcome: a review of the literature with particular attention to exposure to video terminals].

Exposure to extremely low frequency electromagnetic field (EMF) is very common and concern about its harmful effects has been raised. Video display terminals (VDT) in the office are among the most important sources of exposure. Animal studies have shown adverse effects on reproduction, but the role of EMF in human reproduction is not clear. Twelve papers considering the effects of VDT and other EMF exposure on pregnancy outcome are reviewed. Concerning VDT exposure, the pooled OR for spontaneous abortion was 1.0 (95% Confidence Interval, CI, 0.9-1.0). There was no significative trend in risk with exposure intensity. No significative risk emerged for low birth weight nor for congenital malformations. Regarding other sources of EMF (electric blankets, heated waterbeds, ceiling cable electric heat and power lines), some studies have suggested that spontaneous abortion, growth retardation and congenital defects are more frequent during the coldest month of the year (when the exposure to these EMF would have been higher). However, data on the issue are scanty.

Animals↗