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PubMed2003

Spatial correlations and degree of polarization in homogeneous electromagnetic fields.

We consider stationary electromagnetic fields modeled as superpositions of unpolarized and angularly uncorrelated plane waves and show that in anisotropic case the electric cross-spectral tensor is proportional to the imaginary part of the Green tensor. This is as for blackbody radiation, but here the field need not be in thermal equilibrium. We also evaluate the degree of polarization for a homogeneous but nonisotropic field for which the plane waves propagate within a cone of angles. The results are compared with the known polarization properties of blackbody radiation.

Journal Article↗
PubMed2000

The effects of natural and man-made electromagnetic fields on mood and behavior: the role of sleep disturbances.

Natural and man-made electromagnetic fields influence the mood and behavior of healthy and sick people. Considerable evidence suggests that electromagnetic fields affect sleep. The author suggests that electromagnetic field-induced changes in sleep may mediate the effects of electromagnetic fields on mood, behavior, and cognitive abilities. The author further suggests that the development of sleep abnormalities in persons exposed to artificial electromagnetic fields may predict the onset of a psychiatric disorder at a later time and that early intervention may prevent the onset of a psychiatric disease.

Affect↗
PubMed1982

Nonlinear wave mechanisms in interactions between excitable tissue and electromagnetic fields.

It is now well established that intrinsic electromagnetic fields play a key role in a broad range of tissue functions, including embryonic morphogenesis, wound healing, and information transmission in the nervous system. These same processes may be profoundly influenced by eletromagnetic fields induced by an external force. Tissue exposure to extremely low frequency (ELF) and ELF-modulated microwave fields at levels below those inducing significant thermal effects has revealed highly nonlinear mechanisms as a basis for observed effects. Interactions of phonons and excitons along linear molecules may produce nonlinear molecular vibrations in the form of soliton waves. Solitons exist in a minimal energy state and are extremely long-lived in comparison to linear oscillations. Solitons may convey energy released by chemical reactions from one site to another in enzymes of other long-chain proteins. These nonlinear waves may also couple reaction-diffusion processes in the intracellular and extracellular domains. A model is proposed for interaction between excitable tissue and electromagnetic fields, based on nonlinear waves in the cell membrane, with ionic interactions as an essential step. Calcium fluxes in the extracellular space of the central system are modeled by a nonlinear reaction-diffusion system. Membrane molecular solitons may exist in long-chain molecules (Davydov type) and play a significant role in charge transfer; or they may exist as nonlinear waves conveying energy along gel-lipid domains from one protein site to another (Sine-Gordon soliton). Soliton movements occur at subsonic velocities.

Animals↗
PubMed2003

The effect of the pulsatile electromagnetic field in children suffering from bronchial asthma.

From the bibliography it is well known that pulsatile electromagnetic field has an anti-inflammatory and analgesic effect. It causes vasodilatation, myorelaxation, hyper-production of connective tissue and activation of the cell membrane. Therefore our aim was to study the possible therapeutic effect of pulsatile electromagnetic field in asthmatic children. Forty-two children participating in this study were divided in two groups. The 1st group consisting of 21 children (11 females, 10 males, aged 11.8 +/- 0.4 yr) was treated by pulsatile electromagnetic field and pharmacologically. The 2nd group served as control, consisting also of 21 children (11 females, 10 males, aged 11.7 +/- 0.3 yr) and was treated only pharmacologically. Therapeutic effect of the pulsatile electromagnetic field was assessed on the basis of pulmonary tests performed by means of a Spirometer 100 Handi (Germany). The indexes FVC, IVC, ERV, IRV, FEV1, FEV1/FVC%, MEF75,50,25, PEF, PIF and the changes of the flow-volume loop were also registered. The pulsatile electromagnetic field was applied by means of the device MTU 500H, Therapy System (Brno, Czech Republic) for 5 days, two times daily for 30 minutes (magnetic induction: 3 mT, frequency: 4 Hz as recommended by the manufacturer). The results in children of the 1st group showed an improvement of FVC of about 70 ml, IVC of about 110 ml, FEV1 of about 80 ml, MEF75 of about 30 ml, PEF of about 480 ml, PIF of about 550 ml. The increases of ERV, IRV and FEV1/FVC and decreases of MEF25,50 were statistically insignificant. The results in the 2nd group were less clear. The flow-volume loop showed a mild improvement in 14 children. This improvement in the 2nd group was less significant. The clinical status of children and their mood became better. We believe that the pulsatile electro-magnetotherapy in children suffering from asthma is effective. On the basis of our results we can recommend it as a complementary therapy.

Asthma↗
PubMed1994

Electromagnetic field focusing instrument augments resection of meningiomas.

The electromagnetic field focusing (EFF) surgical instrument creates an oscillating electromagnetic field that induces eddy currents in the tissue, which converge at the point of contact. This energy creates a focal spark capable of vaporizing tissue. The EFF instrument was used to resect 17 meningiomas in 14 patients. The effectiveness of the EFF probe in resecting tumor tissue was compared with that of the Cavetron ultrasonic surgical aspirator (Model 100) in 11 patients. The EFF system was superior to the Cavetron ultrasonic surgical aspirator in tumor excision in all but two cases, in which the EFF grounding tip was poorly tuned. Surgical time and blood loss were reduced by subjective analysis in all but these two cases, especially in the rubbery or calcified meningiomas resistant to aspiration. No complications were directly attributable to use of the EFF. Drawbacks encountered with the EFF system include buildup of "char" on the tip, requiring scraping, and intense heat at the tip, which occasionally melted the insulating sheath, requiring replacement.

Adult↗
PubMed1994

[Effects of electromagnetic field emitted by electric blankets on brain catecholamine in fetal mice].

A study of effects of electromagnetic field emitted by electric blankets on brain catecholamine (CA) content in fetal mice under development was carried out, to determine which component of the electromagnetic field, electric field or magnetic field or both, causes the effects, and to improve the design of the electric blankets. Forty-eight NIH pregnant mice were divided into three groups exposed to electric field, magnetic field and electromagnetic field, respectively for five hours daily during mice's whole gestational periods, and one control group. Twelve infant mice in each group were decapitated at the seventh day after delivery, and sagittal sections of the middle part of their brain were prepared for quantitative histofluorescence analysis of CA with a microspectrophotometer. Results showed brain CA content in all the exposed groups was lower than that in controls, with F values of 18.5 and 37.6 in hypothalamus and hippocampus, respectively. Both electric and magnetic fields could decrease brain CA content in mice, but electric fields had greater effects. It suggested the focus in production of electric blankets should be put on reducing electric field, as well as reducing magnetic field by cloth wiring design. Electric field lowered to less than 100 V/m for the electric blankets with such design from 1 kV/m, and magnetic field to less than 0.08 microT from 1 microT.

Animals↗
PubMed1983

Pulsing electromagnetic fields induce cellular transcription.

Weak, pulsing electromagnetic fields can modify biological processes. The hypothesis that responses to such induced currents depend on pulse characteristics was evaluated by using transcription as the target process. Two pulses in clinical use, the repetitive single pulse and the repetitive pulse train, were tested. These pulses produced different results from each other and from controls when transcription in dipteran salivary gland cells was monitored with tritiated uridine in transcription autoradiography, cytological nick translation, and analysis of isolated RNA fractions. The single pulse increased the specific activity of messenger RNA after 15 and 45 minutes of exposure. The pulse train increased specific activity only after 45 minutes of exposure.

Animals↗
PubMed1988

Bone ingrowth into porous calcium phosphate ceramics: influence of pulsing electromagnetic field.

The effect of a pulsing electromagnetic field (PEMF) on bone ingrowth into porous hydroxyapatite (HA) and porous tricalcium phosphate (TCP) implanted in rabbit tibiae was studied. To quantitate the biological response, a recently developed method of surface measurement using a scanning electron microscope was used. The morphometrical findings in the HA pores demonstrated a significantly greater amount of bone and thicker bone trabeculae in the PEMF group as compared with the nonpulsed control group at 3 to 4 weeks postimplantation. No significant differences for these parameters were found in the TCP pores. Histologically, more bone and wider bone trabeculae were observed in the HA implants for the PEMF-treated animals at the early time periods when compared with those of the control animals. Alternatively, the histological findings of the TCP implants were similar between these two groups. These histological results tended to correlate with the morphometrical data. Together, these results suggest that accelerated bone formation and bone maturation occurred in response to PEMF in the HA pores but was without effect in the TCP pores. This stimulatory effect is most significant after 3-4 weeks of PEMF stimulation.

Animals↗
PubMed2001

Pulsed electromagnetic fields increase growth factor release by nonunion cells.

The mechanisms involved in pulsed electromagnetic field stimulation of nonunions are not known. Animal and cell culture models suggest endochondral ossification is stimulated by increasing cartilage mass and production of transforming growth factor-beta 1. For the current study, the effect of pulsed electromagnetic field stimulation on cells from human hypertrophic (n = 3) and atrophic (n = 4) nonunion tissues was examined. Cultures were placed between Helmholtz coils, and an electromagnetic field (4.5-ms bursts of 20 pulses repeating at 15 Hz) was applied to 1/2 of them 8 hours per day for 1, 2, or 4 days. There was a time-dependent increase in transforming growth factor-beta 1 in the conditioned media of treated hypertrophic nonunion cells by Day 2 and of atrophic nonunion cells by Day 4. There was no effect on cell number, [3H]-thymidine incorporation, alkaline phosphatase activity, collagen synthesis, or prostaglandin E2 and osteocalcin production. This indicates that human nonunion cells respond to pulsed electromagnetic fields in culture and that transforming growth factor-beta 1 production is an early event. The delayed response of hypertrophic and atrophic nonunion cells (> 24 hours) suggests that a cascade of regulatory events is stimulated, culminating in growth factor synthesis and release.

Adult↗
PubMedDate not supplied

The effect of pulsed electromagnetic field on patients with endocrine ophthalmopathy.

PURPOSE: To evaluate eye signs, proptosis and ocular movements in patients with endocrine ophthalmopathy under the influence of pulsed electromagnetic field therapy. METHODS: We examined 14 patients (9 women, 5 men) with endocrine ophthalmopathy and evaluated eye signs, proptosis and ocular movements before and after the course of pulsed electromagnetic field therapy, and 12 controls. Their age ranged from 29 to 57 years. Visual sensitivity was investigated with a static automatic perimeter (Allergan Humphrey Field Analyzer). The score was calculated by rating the severity of involvement of soft tissue, proptosis, extraocular movements, corneal state and optic nerve function on a scale from 0 to 3. The pulsed electromagnetic field procedures were carried out with the help of electromagnetic spectacles. RESULTS: Pulsed electromagnetic field therapy reduced the score for soft tissue and proptosis in patients who suffered from endocrine ophthalmopathy. There was fall in the mean score for ocular movements, corneal and optic nerve function but it did not reach significance after treatment. Electromagnetic field therapy has no useful effect on visual signs and eye movements in two patients who had had the illness more than two years. CONCLUSIONS: Localised pulsed electromagnetic field procedures can be recommended, together with other methods of conservative treatment of endocrine ophthalmopathy.

Adult↗
PubMedDate not supplied

The effect of pulsed electromagnetic fields on hindfoot arthrodesis: a prospective study.

The aim of this study was to evaluate the effect of pulsed electromagnetic fields in a consecutive series of 64 patients undergoing hindfoot arthrodesis (144 joints). All patients who underwent elective triple/subtalar arthrodesis were randomized into control and pulsed electromagnetic field study groups. Subjects in the study group had an external pulsed electromagnetic fields device applied over the cast for 12 hours a day. Radiographs were taken pre- and postoperatively until radiographic union occurred. A senior musculoskeletal radiologist, blinded to the treatment scheme, evaluated the radiographic parameters. The average time to radiographic union in the control group was 14.5 weeks in 33 primary subtalar arthrodeses. There were 4 nonunions. The study group consisted of 22 primary subtalar arthrodeses and 5 revisions. The average time to radiographic union was 12.9 weeks (P =.136). The average time to fusion of the talonavicular joint in the control group was 17.6 weeks in 19 primary procedures. In the pulsed electromagnetic fields group of 20 primary and 3 revision talonavicular arthrodeses, the average time to radiographic fusion was 12.2 weeks (P =.003). For the 21 calcaneocuboid arthrodeses in control group, the average time to radiographic fusion was 17.7 weeks; it was 13.1 weeks (P =.010) for the 19 fusions in the study group. This study suggests that, if all parameters are equal, the adjunctive use of a pulsed electromagnetic field in elective hindfoot arthrodesis may increase the rate and speed of radiographic union of these joints.

Arthrodesis↗
PubMedDate not supplied

[Exposure of nursing personnel to electromagnetic fields in neonatal intensive care].

Electromagnetic fields (EMF) are recognised as a source of environmental pollution for workers and people resident in exposed areas. The level of exposure to EMFs of the nurses working in the Siena Neonatal Intensive Care Unit, during two workdays was recorded and peak levels > 10 mG (1 microT) were registered well above an almost permanence exposure at > 2 mg G. The application of existing standard, cautionary criteria and rules would suggest protective or restrictive measures against EMF exposure for these workers.

Electromagnetic Fields↗
PubMed2006

Automated external defibrillators do not recommend false positive shocks under the influence of electromagnetic fields present at public locations.

Electromagnetic fields (EMF) reduce the signal quality of electrocardiograms and may lead to the misinterpretation by automated external defibrillators (AED). We designed this investigation as a prospective study, with a randomized sequence of AED applications on healthy volunteers. We chose busy public places where public access defibrillation was possible as test locations. Strong EMF were sought and found at train stations next to accelerating and decelerating trains. The primary outcome variable was the absolute number of shocks advised in the presence of sinus rhythm by five commonly used AED in Austria. For data analysis, the statistician was blinded in regard to the AED models tested. Data analysis was based on a per protocol evaluation. Of 390 tests run, 0 cases of false positive results occurred (95% CI: 0-0.77). AED can be regarded as safe, even with the interference of EMF present at train stations.

Defibrillators↗
PubMedDate not supplied

Reproductive and teratologic effects of electromagnetic fields.

The reproductive risks of electromagnetic fields (EMF) were evaluated based on an extensive review of the scientific literature pertaining to human epidemiologic studies, secular trend data, in vivo animal studies and in vitro studies, and biologic plausibility. The epidemiologic studies involving the reproductive effects of EMF exposures to human populations have included populations exposed to: (1) video display terminals (VDTs), and (2) power lines and household appliances. The clinical use of diagnostic MRI (magnetic resonance imaging) has been increasing, but there are few reports or studies of pregnant women or individuals of reproductive age who have been exposed to MRI, and whose reproductive performance has been evaluated. The population that has been studied most frequently are women exposed to VDTs, but their EMF exposures are extremely low and frequently are at the level of the ambient EMF in a house or office. The results of epidemiologic studies involving VDTs are generally negative for the reproductive effects that have been studied. Based on the number of studies, the exposure levels, and the fairly consistent results, it can be argued that VDT epidemiologic studies should no longer be given priority. There have been fewer studies concerned with the reproductive risks of power lines, electric substations, and home appliances. In some publications, positive findings for reproductive risks were reported, but the more consistent findings indicate that EMF, even at these higher exposures, do not generate a measurable increase in reproductive failures in the human population. When compared to other fields of human epidemiology, it is obvious that these studies have many difficulties. Exposures are rarely determined. Studies frequently involve small sample sizes and the investigators rarely have a combined expertise in EMF physics, engineering, and reproductive biology. Because of the allegation that there may be particular windows of frequency, wave shape, and intensity that may be deleterious, it is impossible to disregard low frequency EMF exposures as having no deleterious reproductive effects. Yet the epidemiologic data that are available would point in that direction. Secular trend data analysis of birth defect incidence data indicate that increasing generation of electric power during this century is not associated with a concomitant rise in the incidence of birth defects. There are over 70 EMF research projects dealing with animal and in vitro studies that are concerned with some aspect of reproduction and growth. Unfortunately, a large proportion of the embryology studies utilized the chick embryo and evaluated the presence or absence of teratogenesis after 48 to 52 hours of development.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Modulation of bone loss during disuse by pulsed electromagnetic fields.

The effect of pulsed electromagnetic fields (PEMFs) on bone loss associated with disuse was investigated by applying 1.5 Hz repetitions of 30 ms bursts of asymmetric pulses, varying from +2.5 to -135 mV, to bones deprived of their normal functional loading. The proximal portion of one fibula in each of a group of ovariectomised adult female beagle dogs was isolated from functional loading in vivo by proximal and distal osteotomies. Comparison of these prepared bones with their intact contralateral controls after 12 weeks, showed a 23% reduction in cross-sectional area. In similarly prepared bones exposed to PEMFs for 1 h per day, 5 days per week, this bone loss was substantially and significantly reduced to 9% (p = 0.029). There was no evidence of any new bone formation on the periosteal surface of prepared fibulae in treated or untreated situations. PEMF treatment was not associated with any significant change in number of osteons per mm2 formed within the cortex of the bones, their radial closure rate, or their degree of closure. The modulation in loss of bone area associated with exposure to PEMFs can, therefore, be inferred to be due to a reduction in resorption on the bone surface.

Animals↗
PubMed2004

[Exposure of nurses to electromagnetic fields].

BACKGROUND: Devices that produce electromagnetic fields (EMF) within the range of 0-300 GHz are widely used in surgical and diagnostic procedures. As a result a large number of physicians and other groups of medical personnel may be exposed to EMF. Even if patients' exposure, sometimes quite high, is inevitable or even recommended, medical personnel should be substantially protected against EMF exposure. MATERIALS AND METHODS: Evaluation of nurses' exposure to EMF was based on an analysis of EMF magnitudes in the surrounding of magnetic resonance imaging (MRI) and electrosurgical units. These two kinds of apparatus are the strongest EMF sources in health service facilities. The measurements were performed according to the norms and hygiene regulations binding in Poland. Measurements performed by the Nofer Institute of Medicine in Lódź, and data collected by the Central Database on EMF Sources were used in the analysis. The Central Database is run by the Nofer Institute of Medicine at the behest of the Chief Sanitary Inspector. RESULTS: The study showed that nurses' exposure to EMF emitted by MRI and electrosurgical units complies with Polish norms and hygiene regulations and can be classified as negligible or allowable. CONCLUSIONS: It was found that work of nurses in exposure to EMF emitted by MRI and electrosurgical units can be regarded as safe, which means that their health should not be endangered by performing their job.

Dose-Response Relationship, Radiation↗
PubMed1985

The effect of pulsating electromagnetic fields on condylar growth in guinea pigs.

The purpose of this study was to determine if a simple, noninvasive method could be developed for the application of pulsed electromagnetic fields that would lend itself to future clinical applications. Specifically, the modulation and control of condylar cellular metabolism and the stimulation of cellular proliferation were attempted in order to increase the amount of mandibular condylar growth. A pulsed electromagnetic field with a frequency of 100 hertz was applied for 8 hours per day to the mandibular condylar area of rapidly growing, male, Hartley guinea pigs. Ten guinea pigs were exposed for 10 days and a second group of 10 guinea pigs was exposed for 30 days. In addition, 5 guinea pigs were used as controls for each experimental period. During the experimental period the guinea pigs were placed in specially constructed, plastic animal holders with their heads positioned in an area of uniform magnetic field. After 10 days of pulsed electromagnetic field exposure, there were increases in vascularity, secretion of cartilagenous intercellular matrix, and woven-bone formation in the guinea pig condyle. After 30 days, there were continued but attenuated vascular and calcification responses with an increase noted in marrow hemopoietic elements. An increase in the number of osteoclasts was also noted after 10 days. This effect was transient and was not present at the end of the 30-day experimental period. The application of the pulsed electromagnetic field did not result in a significant increase in the overall anteroposterior or vertical size of the guinea pig mandible compared to controls. The results of this study suggest that it is possible to affect condylar cartilagenous and bony metabolism through the application of a noninvasive, pulsed electromagnetic field.

Animals↗
PubMed1993

Effects of electromagnetic field exposure on gene transcription.

Exposure of whole animals, isolated tissues, and cells to electromagnetic fields of various characteristics has resulted in a substantial literature detailing a wide range of effects at the morphological, physiological, biochemical, and molecular levels. In recent years, considerable effort has been devoted to defining a mechanism by which electromagnetic fields can couple to biological systems and generate this plethora of effects. As a consequence, there has been a growing interest in electromagnetic field-induced alterations in gene expression. Key studies are discussed which indicate that exposure of several cell types to electromagnetic fields that differ in waveform, amplitude, and frequency induced general changes in gene transcription. Moreover, exposure of T-lymphoblastoid cells to a 60 Hz sinusoidal magnetic field altered the transcription of genes encoding c-fos, c-jun, c-myc, and protein kinase C. Future studies in this area should focus on independent replication of key studies and identification of which events in the signal transduction pathways leading to gene transcription are altered by electromagnetic field exposure.

Animals↗