Resonant ac-dc magnetic fields: calculated response

An elementary model consisting of one charged particle in a viscous medium exposed to weak ac-dc low-frequency magnetic fields is analyzed to identify and explain the fundamental characteristics of the physical mechanisms that result in a resonance response, which is similar to the familiar cyclotron resonance. The model predicts both frequency and amplitude windows, which are explained in terms of synchronization of the particle with electric fields. Although extrapolation of model results to biological systems is limited by the elementary nature of the model, the model results indicate that observed resonant responses by others of biological systems to ac-dc magnetic fields are probably not due to resonant response of ions in solution, since the model predicts that no resonant response is possible unless the viscous damping is very low, many orders of magnitude lower than the viscous damping of ions in solution.     

Modulation of Ca2+ dependent protease activity in fish and invertebrates by weak low-frequency magnetic fields

Results of experiments addressing the effects of weak low-frequency magnetic fields on intracellular Ca²⁺ dependent proteinases (calpains) from invertebrates and fish are discussed. Exposure of live animals to weak low-frequency magnetic fields with parameters chosen to induce the resonance of Ca²⁺ ions led to a significant decrease of calpain activity in the animals investigated. The physical factor studied also caused partial loss of activity in preparations of Ca²⁺ dependent proteinases obtained from invertebrates and fish. The phenomenon discovered is in accordance with the interference model of the effect of weak low-frequency magnetic fields on biological objects.     

A few remarks on 'combined action of DC and AC magnetic fields on ion motion in a macromolecule'

Zhadin and Barnes [2005:26:323-330] concluded that they solved the differential equation describing combined action of DC and AC magnetic fields on thermal motion of ions in a biological macromolecule and, as a result, a diversity of biological phenomena could be explained. It is shown here that biological phenomena cannot be explained based on this model. Adair [2006:27:332-334] gave several arguments for the statement that the interaction of weak magnetic fields with ions trapped in protein cavities cannot produce detectable biological effects through changing the character of the ion orbits. The arguments are analyzed here and some are shown to be questionable or unjustified. We stress the difference between the conclusion made by Adair and that stated in this article.     

Clarification and application of an ion parametric resonance model for magnetic field interactions with biological systems

Theoretical models proposed to date have been unable to clearly predict biological results from exposure to low-intensity electric and magnetic fields (EMF). Recently a predictive ionic resonance model was proposed by Lednev, based on an earlier atomic spectroscopy theory described by Podgoretskii and Podgoretskii and Khrustalev. The ion parametric resonance (IPR) model developed in this paper corrects mathematical errors in the earlier Lednev model and extends that model to give explicit predictions of biological responses to parallel AC and DC magnetic fields caused by field-induced changes in combinations of ions within the biological system. Distinct response forms predicted by the IPR model depend explicitly on the experimentally controlled variables: magnetic flux densities of the AC and DC magnetic fields (B_ac and B_dc, respectively); AC frequency (f_ac); and, implicitly, charge to mass ratio of target ions. After clarifying the IPR model and extending it to combinations of different resonant ions, this paper proposes a basic set of experiments to test the IPR model directly which do not rely on the choice of a particular specimen or endpoint. While the fundamental bases of the model are supported by a variety of other studies, the IPR model is necessarily heuristic when applied to biological systems, because it is based on the premise that the magnitude and form of magnetic field interactions with unhydrated resonant ions in critical biological structures alter ion-associated biological activities that may in turn be correlated with observable effects in living systems. © 1994 Wiley-Liss, Inc.     

Comment: analyses of models of ion actions under the combined action of AC and DC magnetic fields

I show that the interaction of weak DC and ELF magnetic fields with contained ions cannot generate significant biological effects through changing the character of the ion orbits.     

Amplitude and frequency dissociation spectra of ion-protein complexes rotating in magnetic fields

A mechanism is presented that predicts new biological effects of static and sinusoidal weak magnetic fields. The model is based on an earlier proposed interference mechanism of quantum states of ions within protein cavities. The quantum dynamics of an ion is studied for the case of ion-protein complexes that rotate in magnetic fields. Both the individual molecular rotation and rotation together with a biological sample are taken into account. A formula is derived for the magnetic field-dependent part of the dissociation probability of an ion-protein in these conditions. The formula explains the unusual amplitude dependence of the known biological effect in PC-12 cells exposed to AC-DC magnetic field. The dependence had the functional motif J(2)(1)(2H(AC)/H(DC)), where J(1) is the first order Bessel function of the first kind. A good fit was obtained assuming individual rotation of the Li-protein complex in MF. The macroscopic rotation of a biological system, even at low speed 1.5-2 Hz, is predicted to reduce the biological effects of a "magnetic vacuum" and to shift the spectral peaks in the field and frequency dependencies of some magnetobiological effects.     

Possible mechanism for radial ion acceleration in a beam-plasma discharge

A mechanism is proposed that can lead to radial ion acceleration in a plasma discharge excited by an electron beam in a relatively weak longitudinal magnetic field. The mechanism operates as follows. The beam generates an azimuthally asymmetric slow potential wave, which traps electrons. Trapped magnetized electrons drift radially with a fairly high velocity under the combined action of the azimuthal wave field (which is constant for them) and a relatively weak external longitudinal magnetic field. The radial electron flux generates a radial charge-separation electric field, which accelerates unmagnetized plasma ions in the radial direction. The ion flux densities and energies achievable in experiments with kiloelectronvolt electron beams in magnetic fields of up to 100 G are estimated.     

NEW BIOLOGICAL DETECTION SYSTEM FOR WEAK ELF MAGNETIC FIELDS AND TESTING OF THE PARAMETRIC RESONANCE MODEL (Lednev 1991)

A new detection system for weak, extremely low frequency (ELF) magnetic fields based on bioluminescence of the autotrophic dinoflagellate Gonyaulax sp. is presented. Due to its sensitivity to external factors, this biological system has already been thoroughly investigated and used for various biological research. In our study, the system was first tested for its capacity to respond to weak ELF magnetic fields (50 Hz, 11.5 mT; 50 Hz, 1.2 mT). After its sensitivity was established, the system was used to test the parametric resonance model proposed by Lednev in 1991. Our results seem to be consistent with the model predictions, especially when monitoring real-time effects of the exposure.     

Interaction between weak low frequency magnetic fields and cell membranes

The question of whether very weak low frequency magnetic fields can affect biological systems, has attracted attention by many research groups for quite some time. Still, today, the theoretical possibility of such an interaction is often questioned and the site of interaction in the cell is unknown. In the present study, the influence of extremely low frequency (ELF) magnetic fields on the transport of Ca(2+) was studied in a biological system consisting of highly purified plasma membrane vesicles. We tested two quantum mechanical theoretical models that assume that biologically active ions can be bound to a channel protein and influence the opening state of the channel. Vesicles were exposed for 30 min at 32 degrees C and the calcium efflux was studied using radioactive (45)Ca as a tracer. Static magnetic fields ranging from 27 to 37 micro T and time varying magnetic fields with frequencies between 7 and 72 Hz and amplitudes between 13 and 114 micro T (peak) were used. We show that suitable combinations of static and time varying magnetic fields directly interact with the Ca(2+) channel protein in the cell membrane, and we could quantitatively confirm the model proposed by Blanchard.     

Criticism of Lednev's mechanism for the influence of weak magnetic fields on biological systems.

V. V. Lednev has proposed a mechanism that he suggests would allow very weak magnetic fields, at the cyclotron resonance frequency for Ca2+ ions in the earth's field, to induce biological effects. I show that for four independent reasons no such mechanism can operate.     

Mechanism of action of combined extremely weak magnetic field on aqueous solution of amino acid

The fundamental physical mechanisms of resonance action of an extremely weak (40 nT) alternating magnetic field at the cyclotron frequency combined with a weak (40 μT) static magnetic field, on living systems are analyzed in the present work. The experimental effects of such sort of magnetic fields were described in different papers: the very narrow resonant peaks in electrical conductivity of the aqueous solutions in the in vitro experiments and the biomedical in vivo effects on living animals of magnetic fields with frequencies tuned to some amino acids. The existing experimental in vitro data had a good repeatability in different laboratories and countries. Unfortunately, for free ions such sort of effects are absolutely impossible because the dimensions of an ion rotation radius should be measured by meters at room temperature and at very low static magnetic fields used in all the above experiments. Even for bound ions these effects should be also absolutely impossible from the positions of classic physics because of rather high viscosity of biological liquid media (blood plasma, cerebrospinal liquid, cytoplasm). Only modern quantum electrodynamics of condensed media opens the new ways for solving these problems. The proposed article is devoted to analysis of quantum mechanisms of these effects.     

Calcium efflux of plasma membrane vesicles exposed to ELF magnetic fields-test of a nuclear magnetic resonance interaction model

The question whether very weak, low frequency magnetic fields can affect biological matter is still under debate. The theoretical possibility of such an interaction is often questioned and the site of interaction in the cell is unknown. In the present study, the influence of extremely weak 60 Hz magnetic fields on the transport of Ca²⁺ was studied in a biological system consisting of highly purified plasma membrane vesicles. We tested a newly proposed quantum mechanical model postulates that polarization of hydrogen nuclei can elicit a biological effect. Vesicles were exposed for half an hour at 32 °C and the calcium efflux was studied using radioactive ⁴⁵Ca²⁺ as a tracer. A static magnetic field of 26 µT and time‐varying magnetic fields with a frequency of 60 Hz and amplitudes between 0.6 and 6.3 µT were used. The predictions of the model, proposed by Lednev, that at a frequency of 60 Hz the biological effect under investigation would significantly be altered at the amplitudes of 1.3 and 3.9 µT could not be confirmed. Bioelectromagnetics 33:535–542, 2012. © 2012 Wiley Periodicals, Inc.     

Magnetobiology: the kT paradox and possible solutions

The article discusses the so-called 'kT problem' with its formulation, content, and consequences. The usual formulation of the problem points out the paradox of biological effects of weak low-frequency magnetic fields. At the same time, the formulation is based on several implicit assumptions. Analysis of these assumptions shows that they are not always justified. In particular, molecular targets of magnetic fields in biological tissues may operate under physical conditions that do not correspond to the aforementioned assumptions. Consequently, as it is, the kT problem may not be an argument against the existence of non thermal magnetobiological effects. Specific examples are discussed: magnetic nanoparticles found in many organisms, long-lived rotational states of some molecules within protein structures, spin magnetic moments in radical pairs, and magnetic moments of protons in liquid water.     

An elementary bioelectrical generator of the anisotropic homogeneous myocardium and its extracellular field

On the basis of the bidomain model that takes into account the electric anisotropy of body tissues, analytical relationships were developed for calculating the characteristics of electric and magnetic fields produced by an elementary (dipole) bioelectric generator that arises in the electrogenic excitable tissue of the myocardium. The errors in the identification of intensity and location of the bioelectric generator in the myocardium were estimated from the measurements of its external fields (noninvasive identification of the excited region) using approximate methods based on isotropic models of the physical medium.     

The effect of static magnetic fields on the rate of calcium/calmodulin-dependent phosphorylation of myosin light chain

This study reports an attempt to confirm a published and well-defined biological effect of magnetic fields. The biological model investigated was the phosphorylation of myosin light chain in a cell free system. The rate of phosphorylation has been reported to be affected in an approximately linear manner by static magnetic field strengths in the range 0-200 microT. We performed three series of experiments, two to test the general hypothesis and a third that was a direct replication of published work. We found no effect of static magnetic field strength on the rate of phosphorylation. Hence, we were unable to confirm that weak static magnetic fields affect the binding of calcium to calmodulin. In view of the difficulty we and other authors have had making independent verifications of claimed biological effects of magnetic fields, we would urge caution in the interpretation of published data until they have been independently confirmed. There are still few well defined biological effects of low level magnetic fields that have been successfully transferred to an independent laboratory.     

Dynamic characteristics of membrane ions in multifield configurations of low-frequency electromagnetic radiation

We seek to extend the recent suggestion that classical cyclotron resonance of biologically important ions is implicated in weak electromagnetic field-cell interactions. The motion of charged particles in a constant magnetic field and periodic electric field is examined under the simplifying assumption of no damping. Each of the nine terms of the relative dielectric tensor is found to have a dependence on functions that include the factor (omega 2 - omega 2B)-1, where omega B is the gyrofrequency. We also find a plasmalike decomposition of the electric field into oppositely rotating components that could conceivably act to drive oppositely charged ions in the same direction through helical membrane channels. For weak low-frequency magnetic fields, an additional feature arises, namely, periodic reinforcement of the resonance condition with intervals of the order of tens of msec for biological ions such as Li+, Na+, and K+.     

Effect of weak and superweak magnetic fields on intensity and asexual reproduction of the planarian Dugesia tigrina

It was shown that the exposure to combined weak and extraweak magnetic fields (permanent component 42 microT; variable component of an amplitude of 100 nT, frequency 1-60 Hz) increases the intensity of asexual propagation of planarians Dugesia tigrina. The effect of combined magnetic fields is most pronounced at frequencies of 1, 3.7, and 32 Hz. The presence of concomitant technogeneous fields (50 Hz, 30 nT) does not markedly influence the effects of weak magnetic fields with a small variable component. Upon realization of effects of weak magnetic fields, their both components are of great importance; the absence of one (permanent) component changes the sing of the effect to the opposite. The transfer of the effect to planarians through water pretreated with magnetic fields probably indicates that aqueous medium is involved in the realization of biological effects of weak magnetic fields.     

细胞离子在振荡电磁场作用下的受力模型分析

本文通过生物细胞模型,研究振荡电场、振荡磁场以及振荡磁场产生的感应电场对细胞离子的作用机理。模型分析结果表明,电场力和罗仑兹力对细胞膜两侧的自由离子将产生加速度,振荡离子将产生周期性电位移。该模型同时也解释了脉冲电磁场比同参教的连续场产生更多的生物效应,以及连续场在开始施加和切除时的效应最大。     

Effects of weak static magnetic fields on endothelial cells

Pulsed electromagnetic fields (PEMFs) have been used extensively in bone fracture repairs and wound healing. It is accepted that the induced electric field is the dose metric. The mechanisms of interaction between weak magnetic fields and biological systems present more ambiguity than that of PEMFs since weak electric currents induced by PEMFs are believed to mediate the healing process, which are absent in magnetic fields. The present study examines the response of human umbilical vein endothelial cells to weak static magnetic fields. We investigated proliferation, viability, and the expression of functional parameters such as eNOS, NO, and also gene expression of VEGF under the influence of different doses of weak magnetic fields. Applications of weak magnetic fields in tissue engineering are also discussed. Static magnetic fields may open new venues of research in the field of vascular therapies by promoting endothelial cell growth and by enhancing the healing response of the endothelium. Bioelectromagnetics 31:296–301, 2010. © 2010 Wiley‐Liss, Inc.     

Notes on magnetic actions upon the nervous system

Several physical effects (magnetomotive force on ions, magnetic induction of electrical field, magnetic changes of inductance) are quantitatively analyzed in an attempt to attain an insight on how externally applied static magnetic fields influence the activity of the neuron and the Nervous System as a whole or in part. The possible magnetic action on shifting excited zones of the axon appears as most promising for prediction and interpretation of measurable effects. Magnetic fields may modify nervous functions by multiplication and addition of very small biophysical effects.