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At least 1,351 records · Page 75Linked to original sources
PubMed1979

The direct influence of electromagnetic fields on nerve- and muscle cells of man within the frequency range of 1 Hz to 30 MHz.

By using several biophysical approximations and considering man as free space model limiting order-of-magnitude values for external electric and magnetic field strengths which may be hazardous for human beings were calculated. Danger may occur by excitation processes below 30 kHz for field strengths exceeding these limiting values; for frequencies larger than 60 kHz, thermal effects are predominant before excitation occurs. The external electric field strength necessary for causing action potentials in the central nervous system exceeds by far the corona forming level. But excitation is possible by strong alternating magnetic fields. Furthermore, by comparing the electrically and magnetically induced currents with the naturally flowing currents in man caused by the brain's and heart's electrical activity, a "lower boundary-line" was estimated. Regarding electric or magnetic field strengths undercutting this boundary-line, direct effects on the central nervous system may be excluded. Other mechanisms should be responsible for demonstrated biological effects.

Action Potentials↗
PubMed2001

First measurements of the unique influence of spin on the energy loss of ultrarelativistic electrons in strong electromagnetic fields.

Although some authors have claimed that the effect is not detectable, we show experimentally for the first time that as the quantum parameter chi grows beyond 1, an increasingly large part of the hard radiation emitted arises from the spin of the electron. Results for the energy loss of electrons in the energy range 35-243 GeV incident on a W single crystal are presented. Close to the axial direction the strong electromagnetic fields induce a radiative energy loss which is significantly enhanced compared to incidence on an amorphous target. In such continuously strong fields, the radiation process is highly nonperturbative for ultrarelativistic particles and a full quantum description is needed. The remarkable effect of spin flips and the energy loss is connected to the presence of a field comparable in magnitude to the Schwinger critical field, E0 = m(2)c(3)/ePlanck's over 2pi, in the rest frame of the emitting electron.

Journal Article↗
PubMed1993

Human adverse reproductive outcomes and electromagnetic field exposures: review of epidemiologic studies.

Concerns have been raised regarding a relation between residential and occupational electromagnetic (EM) field exposures and adverse reproductive effects. This paper reviews the epidemiologic evidence for this possible relation, including some pertinent methodologic issues, notes relevant findings from the experimental literature, and discusses areas for future research. Evidence is lacking for a strong association between a woman's use of a video display terminal (VDT) during pregnancy and spontaneous abortion. The evidence for a strong association between a women's use of a VDT and other adverse reproductive endpoints is also lacking, with some suggestive findings for congenital malformations and too few data to reach a conclusion about other endpoints. With respect to low-level EM field exposures other than VDTs, the paucity of data prevents one from determining whether there are reproductive health risks associated with such exposures. Therefore, this is an area that needs further investigation. Given that altered growth may be an underlying biologic effect of EM field exposures, endpoints that might be pursued in future studies include congenital malformations not associated with chromosomal anomalies, intrauterine growth retardation, and chromosomally normal spontaneous abortions.

Adult↗
PubMed1995

Changes in the state of water, induced by radiofrequency electromagnetic fields.

Microwave irradiation (f = 36 GHz) changes the properties of distilled water within the first 1-10 min. The new state is retained for at least tens of minutes and manifests itself as changes in power density spectrum of periodic fading voltage fluctuations that are generated during discharge of a capacitor in which water is used as a dielectric. It is assumed that long-term changes in water properties mediate the effect of electromagnetic fields on biological systems.

Microwaves↗
PubMedDate not supplied

[Effect of a low frequency electromagnetic field on biological cells].

Possibility of energy of low frequency electromagnetic waves transformation into the energy of multimodules mechanical vibrations of the biological membrane is proved for spherical and cylindrical models of the cell. Formula for calculating the membrane displacement from equilibrium position is derived.

Cell Membrane↗
PubMed1983

Osteonecrosis of the femoral head treated by pulsed electromagnetic fields (PEMFs): a preliminary report.

This has been a preliminary report with a short-term follow-up of a small number of observations (28 hips of 24 patients). The follow-ups ranged from 6 to 36 months, with an average of 17.8 months. Only eleven hips (in eleven patients) were followed an average of 8 months after cessation of the treatment. It should be emphasized that this was a "pilot" study, in which no control series was used to determine the natural course of the disease in a comparable clinical setting. Of note was the pain relief, in 19 of 23 patients with moderate to severe pretreatment pain. Also there was an improved function, which suggests that at least in approximately two thirds of the patients there was some clinical benefit from this mode of treatment. In eight hips, clinical conditions did not change; and in two they worsened, requiring further treatment. Eighteen remaining hips were thought to have been benefited by the treatment. Six femoral heads that had already developed varying degrees of collapse (Ficat Type III) collapsed further (1 to 2 mm), and two round heads (Ficat II) progressed to off-round (Ficat III). This preliminary study suggests that further exploration of pulsed electromagnetic fields (PEMFs) is warranted in the treatment of osteonecrosis of the femoral head.

Adolescent↗
PubMed2005

Do electromagnetic fields interact with electrons in the Na,K-ATPase?

The effects of low frequency electric and magnetic fields on several biochemical systems, including the Na,K-ATPase, indicate that electromagnetic (EM) fields interact with electrons. The frequency optima for two enzymes in response to EM fields are very close to their turnover numbers, suggesting that these interactions directly affect reaction rates. Nevertheless, generally accepted ideas about Na,K-ATPase function and ion transport mechanisms do not consider interactions with electrons. To resolve the clash of paradigms, we hypothesize interaction with transient electrons and protons that arise from flickering of H-bonds in the hydrated protein. These transient charges in the enzyme could provide a trigger for the sequence of conformation changes that are part of the ion transport mechanism. If the distributions of transient electrons and protons in the membrane are affected by their concentration and the membrane potential, as expected from electric double layer theory, this can account for the different effects of low frequency electric and magnetic fields, as well as for the observation that membrane hyperpolarization reverses the ATPase reaction to generate ATP.

Electromagnetic Fields↗
PubMed1995

Improvement in short-term visual memory by weak electromagnetic fields in Parkinson's disease.

Neuropsychological studies have demonstrated that Parkinson's disease (PD) is associated with various cognitive deficits ultimately leading in about 30% of patients to the development of dementia. These studies have demonstrated also a greater decrement of right hemispheric functions with visuospatial deficits occurring in up to 90% of PD patients. The Rey-Osterrieth Complex Figure (ROCF) Test has been employed in the assessment of right hemispheric functions and particularly for the evaluation of visuoconstructive abilities and short-term visual memory. I have demonstrated recently that external application of electromagnetic fields (EMFs) in the picotesla (pT) range intensity is an effective nonpharmacological modality in the management of the motor and cognitive deficits of Parkinsonism. In the present communication I present 3 fully medicated nondemented PD patients (mean age: 68 +/- 8.1 yrs; mean duration of illness: 9.0 +/- 4.0 yrs; mean disability on the Hoehn and Yahr scale: 3) who were tested on the ROCF Test before and after a series of treatments with EMFs. In response to the administration of EMFs the group demonstrated a mean of 23.1 +/- 13.6% improved performance on copy of the ROCF and a 39.3 +/- 13.4% improvement of short-term recall of the ROCF. These findings demonstrate that treatment with pT EMFs improves deficits in visuospatial functions and visual memory in Parkinsonism which usually remain unaffected during standard treatment with dopaminergic pharmacotherapy.

Aged↗
PubMed1995

Resolution of Lhermitte's sign in multiple sclerosis by treatment with weak electromagnetic fields.

Lhermitte's sign, the occurrence of an electrical sensation passing down the back to the legs on flexion of the neck is a common and characteristic feature of multiple sclerosis (MS) which is related to spinal cord lesions affecting the posterior columns and cervical nerve roots. The Lhermitte's sign, which has been reported to occur at some time in up to 25% of MS patients, is seldom painful but is often a cause of distress to the patient and usually a marker of increased disease activity. Treatment with extracranial picotesla range pulsed electromagnetic fields (EMFs) has been found efficacious in the management of various MS symptoms including pain syndromes. The present communication concerns three MS patients in whom two brief applications of EMFs resulted in resolution of the Lhermitte's sign which emerged during a period of exacerbation of symptoms in one patient and during a prolonged phase of symptom deterioration in the other two patients. As the cause of the Lhermitte's sign is thought to result from the spread of ectopic excitation in demyelinated plaques in the cervical and thoracic regions of the spinal cord, it is hypothesized that the effects of EMFs are related to the reduction of axonal excitability via a mechanism involving changes in ionic membrane permeability. A systemic effect on pain control systems is also postulated to occur secondary to the effects of EMFs on neurotransmitter activity and pineal melatonin functions. This report underscores the efficacy of picotesla EMFs in the management of paroxysmal pain symptoms in MS.

Adult↗
PubMed1995

Improvement of right hemispheric functions in a child with Gilles de la Tourette's syndrome by weak electromagnetic fields.

Gilles de la Tourette's syndrome (GTS) is a chronic, familial neuropsychiatric disorder of unknown etiology characterized clinically by the occurrence of motor and vocal tics and by the presence of a variety of neurobehavioral and neurocognitive abnormalities including hyperactivity, self-multilatory behavior, obsessive-compulsive behavior, learning disabilities, and conduct disorder. On the basis of neuropsychological assessments it has been suggested that GTS is associated with greater right than left hemispheric dysfunction which accounts for decrements in visuospatial, visuoconstructional and visuomotor skills in these patients. Recent case studies have demonstrated that extracranial application of electromagnetic fields (EMFs) in the picotesla (pT) range intensity improves visuospatial and visuoperceptive functions in patients with neurodegenerative disorders including Parkinson's disease, multiple sclerosis and Alzheimer's disease. I now present a 6 1/2 year old boy with GTS in whom this treatment modality produced, in addition to symptomatic behavioral improvement, also improvement in visuoconstructional and visuomotor skills as evidenced on various drawing tasks particularly copy of the Rey-Osterrieth Complex Figure, a task which is especially vulnerable to right hemispheric functions. These findings suggest that pT range EMFs may be useful for the treatment of GTS and related disorders and also reverse some of the cognitive impairments associated with the disease which are related to right hemispheric dysfunction and which contribute to learning disabilities in these patients.

Brain↗
PubMed1995

Weak electromagnetic fields reverse visuospatial hemi-inattention in Parkinson's disease.

Drawing tasks, both free and copied, have achieved a central position in neuropsychological testing of patients with unilateral cerebral dysfunction by virtue of their sensitivity to different kinds of organic brain disorders and their ability to provide information on lateralized brain damage. In the drawings of patients with right hemispheric damage, visuospatial neglect is revealed by the omission of details on the side of the drawing contralateral to the hemispheric lesion. Patients with unilateral cerebral damage, particularly those with left hemispheric damage, also demonstrate a tendency to place their drawings on the side of the page ipsilateral to the cerebral lesion, a phenomenon which has been termed visuospatial hemi-inattention. It has been reported previously that brief external application of alternating pulsed electromagnetic fields (EMFs) in the picotesla (pT) range intensity improved visuoperceptive and visuospatial functions and reversed neglect in Parkinsonian patients. The present communication concerns four fully medicated elderly nondemented Parkinsonian patients (mean age: 74.7 +/- 4.6 yrs; mean duration of illness: 7.7 +/- 5.2 yrs) in whom application of these EMFs produced reversal of visuospatial hemi-inattention related to left hemispheric dysfunction. These findings support prior observations demonstrating that pT EMFs may bring about reversal of certain cognitive deficits in Parkinsonian patients.

Aged↗
PubMed1979

[Nerve regeneration by means of the effect of an intermittent electromagnetic field. Experimental study on a rabbit].

An experiment on healing of transected nerves of rabbits was carried out. Under microsurgical techniques continuity of the nerve was reestablished by end-to-end coaptation without creating a defect, so only the elasticity of the nerve tissue had to be overcome, and by nerve grafting. In both cases treatment with intermittent high frequency magnetic field was applied continuously. Histologic studies revealed that the scar at the suture site matured more quickly than usually and that distal to the site of transection the normal calibre of regenerated axons was reached within a shorter time than previously.

Animals↗