Effects Of Weak Electromagnetic Fields Research Articles

Weak electromagnetic fields alter Ca(2+) handling and protect against hypoxia-mediated damage in primary newborn rat myotube cultures.

Weak electromagnetic fields (WEF) enhance Ca(2+) entry into cells via voltage-gated Ca(2+) channels and affect various aspects of metabolism, structure, and function. However, little information is available on the effect of WEF on skeletal muscle, which depends primarily on intracellular Ca(2+) stores for function and metabolism. Here, we examine the effects of 30min exposure of rat primary myotube cultures to WEF (1.75μT, 16Hz) on Ca(2+) handling and creatine kinase (CK) release. Free myoplasmic Ca(2+) concentration ([Ca(2+) i]) was measured with the ratiometric dye indo-1. WEF did not affect basal [Ca(2+)]i but decreased the twitch [Ca(2+)]i transient in a time-dependent manner, and the twitch amplitude was decreased to ∼30% after 30min. WEF completely abolished the increase in [Ca(2+)]i induced by potassium chloride (∼60mM) but had no effect on the increase induced by caffeine (∼6mM). Hypoxia (2h exposure to 100% argon) resulted in a marked loss of CK into the medium (400% of normoxic value), as well as a rapid (within 20min) and sustained increase in basal [Ca(2+)]i (∼20% above baseline). However, during exposure to WEF, basal [Ca(2+)]i remained constant during the initial 60min of hypoxia and, thereafter, increased to levels similar to those observed in the absence of WEF. Finally, WEF blocked about 80% of hypoxia-mediated CK release (P < 0.05). These data demonstrate that WEF inhibits increases in [Ca(2+)]i by interfering with muscle excitation and protects against muscle damage induced by hypoxia. Thus, WEF may have therapeutic/protective effects on skeletal muscle.

Effect of weak electromagnetic fields on self-organization of highly diluted solutions of alkylated p-sulfonatocalix[6]arene

Effect of weak electromagnetic fields on self-organization of highly diluted solutions of alkylated p-sulfonatocalix[6]arene

Influence of magnetic fields on the hydration process of amino acids: Vibrational spectroscopy study of L‐phenylalanine and L‐glutamine

Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy has been used to investigate the effect of weak electromagnetic fields on the structure of L-glutamine (L-Gln) and L-phenylalnine (L-Phe) in aqueous solution. It has been found that the exposure to a DC field or a 50 Hz AC field, for a short time induces modifications in the spectra of exposed samples in agreement with our preceding observations on glutamic acid. Furthermore, the acid-base equilibrium has been investigated by using the ratio of the intensity of the deprotonated on protonated species. In the case of L-Phe, the exposure induces a measurable shift of acid dissociation constant pKa1 out of the experimental errors, while in case of L-Gln, the effect is under the limit detectable with this method. The phenomenon of the shift of the acid-base equilibrium has been connected elsewhere to modification of the water-water hydrogen bonds in the water around both the backbone and the residue (R). Here we suggest that the magnetic field modifies the water structure around the molecules and changes the hydrophobic interactions allowing the molecules of amino acids to aggregate. The differences observed in the behavior of L-Phe and L-Gln may be related to the differences in the polarity of their residues.

Comparison Between Two Models for Interactions Between Electric and Magnetic Fields and Proteins in Cell Membranes

Investigations on exposure to electromagnetic have generated conflicting results both in epidemiological and laboratory studies, leaving their possible health consequences largely inconclusive. One of the well-reported reasons for the discrepancies is that there is no generally accepted theory to describe the interactions between the very weak electromagnetic fields and the living cells. This work presents a critical evaluation of three theories that describes the effects of weak electromagnetic fields on channel proteins in the cell membrane. The forced ion vibration model appears to explain the opening of ion channel proteins for exposures to low-frequency magnetic fields in the mili-Tesla range. No resonance frequencies or amplitude window effects are predicted in this method. We identify inconsistencies in the forced vibration model and show that the environmental magnetic fields that would be required to elicit opening of channel proteins are much stronger than predicted by the proposers of this model. The Ion Parametric Resonance model predicts a biological response at well-defined resonance frequencies for magnetic fields exceeding about 10 micro-Tesla. The oscillating magnetic field is assumed to act on proteins together with the earth's static magnetic field. This model predicts amplitude windows. We explain how a purely magnetic interaction, where in a two-stage ion magnetic resonance model, the conformation of a protein is changed under the influence of ions attached to its surface, which in turn, changes the function of the protein, can overcome the inherent signal-to-noise problem caused by electric thermal noise. The hydrogen nuclear polarization model predicts a biological response for oscillating magnetic field strengths above 0.1 micro-Tesla. The presence of a static magnetic field is required, and biological effects can be expected for frequencies below a few hundred hertz. All models except the forced vibration model can be applied for amplitude modulated microwaves.

Effects of weak electromagnetic fields on global electrocortical activity

Effects of weak electromagnetic fields are considered on recently proposed covariant and generalized coupling models of global electrocortical activity. A method to calculate the ratio of components of signal velocities is given. First-order shift in frequencies is obtained in the presence of a weak, time-varying magnetic field.

Tissue interactions with nonionizing electromagnetic fields.

Tissue interactions with nonionizing electromagnetic fields.

203 - Possible Mechanisms of Weak Electromagnetic Field Coupling in Brain Tissue

The effects of weak electromagnetic fields have been tested on the efflux of calcium from cerebral tissue of chick and cat. The data strongly suggest that the binding and release of calcium occurs cooperatively as the result of long—range interactions between anionic charge sites on the binding substrate. Extremely low frequency (ELF) fields at frequencies of 6 and 12 Hz and gradients in air of 0.1 to 0.5 V/cm decreased calcium efflux by 12 to 15 per cent. Higher and lower frequencies were without significant effect. For chick tissue, the field threshold in air was 0.1 V/cm and for the cat around 0.6 V/cm. At intensities above and below these levels, effects became statistically insignificant. With 147 MHz amplitude modulated fields, calcium efflux from chick cerebral tissue increased for modulation frequencies from 6 to 20 Hz, with a maximum of more than 15 per cent. No significant changes occurred at higher or lower modulation frequencies, nor with an unmodulated carrier wave. With 450 MHz fields amplitude modulated at 16 Hz, increased calcium efflux from chick cerebral tissue occurred at field intensities between 0.1 and 1.0 mW/cm 2. No increase was noted above or below these levels. This series of amplitude and frequency windows is discussed in relation to possible modes of cooperative organization of cell membrane surface glycoproteins in the binding and release of calcium.