Quantum mechanical aspects of the effects of weak magnetic fields on biological objects

Possible mechanisms of action of weak combined magnetic fields on biological systems have been discussed in terms of quantum mechanics. The approaches proposed make it possible to solve the problem of the failure to compare the energy of active factors with the energy of thermal motion (kT problem). A mechanism of action of combined magnetic fields on biosystems has been proposed.     

Primary physical mechanism of the biological effects of weak magnetic fields

The primary physical mechanism of the magnetoreception of weak magnetic fields is considered. It imposes limits on the magnetic biological effect at the stage prior to the involvement of specific biophysical and biochemical mechanisms, i.e., regardless of the nature of the target of the magnetic field. It has been shown that the biological effects of weak magnetic fields have, in general, non-linear and spectral properties. Observation of these characteristics gives information not only on the gyromagnetic ratio, but also on the parameters of the interaction between the target and its immediate surroundings. This makes it possible for one to develop schemes for the identification of the biophysical mechanisms of magnetoreception.     

Effects and molecular mechanisms of the biological action of weak and extremely weak magnetic fields

A number of effects of weak combined (static and alternating) magnetic fields with an alternating component of tens and hundreds nT at a collinear static field of 42 μT, which is equivalent to the geomagnetic field, have been found: activation of fission and regeneration of planarians Dugesia tigrina, inhibition of the growth of the Ehrlich ascites carcinoma in mice, stimulation of the production of the tumor necrosis factor by macrophages, decrease in the protection of chromatin against the action of DNase 1, and enhancement of protein hydrolysis in systems in vivo and in vitro. The frequency and amplitude ranges for the alternating component of weak combined magnetic fields have been determined at which it affects various biological systems. Thus, the optimal amplitude at a frequency of 4.4 Hz is 100 nT (effective value); at a frequency of 16.5 Hz, the range of effective amplitudes is broader, 150–300 nT; and at a frequency of 1 (0.5) Hz, it is 300 nT. The sum of close frequencies (e.g., 16 and 17 Hz) produces a similar biological effect as the product of the modulating (0.5 Hz) and carrying frequencies (16.5 Hz), which is explained by the ratio A = A ₀sinω₁ t + A ₀sinω₂ t = 2A ₀sin(ω₁ + ω₂)t/2cos(ω₁–ω₂)t/2. The efficiency of magnetic signals with pulsations (the sum of close frequencies) is more pronounced than that of sinusoidal frequencies. These data may indicate the presence of several receptors of weak magnetic fields in biological systems and, as a consequence, a higher efficiency of the effect at the simultaneous adjustment to these frequencies by the field. Even with consideration of these facts, the mechanism of the biological action of weak combined magnetic fields remains still poorly understood.     

Possible mechanism for the influence of weak magnetic fields on biological systems

A physical mechanism is suggested for a resonant interaction of weak magnetic fields with biological systems. An ion inside a Ca(2+)-binding protein is approximated by a charged oscillator. A shift in the probability of ion transition between different vibrational energy levels occurs when a combination of static and alternating magnetic fields is applied. This in turn affects the interaction of the ion with the surrounding ligands. The effect reaches its maximum when the frequency of the alternating field is equal to the cyclotron frequency of this ion or to some of its harmonics or sub-harmonics. A resonant response of the biosystem to the magnetic field results. The proposed theory permits a quantitative explanation for the main characteristics of experimentally observed effects.     

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.     

Extremely low-frequency magnetic fields of transformers and possible biological and health effects

Physiological processes in organisms can be influenced by extremely low-frequency (ELF) electromagnetic energy. Biological effect studies have great importance; as well as measurement studies since they provide information on the real exposure situations. In this study, the leakage magnetic fields around a transformer were measured in an apartment building in Küçükçekmece, Istanbul, and the measurement results were evaluated with respect to the international exposure standards. The transformer station was on the bottom floor of a three-floor building. It was found that people living and working in the building were exposed to ELF magnetic fields higher than the threshold magnetic field value of the International Agency for Research on Cancer (IARC). Many people living in this building reported health complaints such as immunological problems of their children. There were child-workers working in the textile factories located in the building. Safe distances or areas for these people should be recommended. Protective measures could be implemented to minimize these exposures. Further residential exposure studies are needed to demonstrate the exposure levels of ELF magnetic fields. Precautions should, therefore, be taken either to reduce leakage or minimize the exposed fields. Shielding techniques should be used to minimize the leakage magnetic fields in such cases.     

Cell response to extremely weak static magnetic fields

The effect of an extremely weak static magnetic field (EWSMF) was studied in diploid fibroblast strains that originated from a healthy donor and an ataxia–telangiectasia patient. Indirect immunofluorescence was used to detect p53, p53BP1, and p21. The pattern that occurred in donor cells exposed to EWSMF similar to that observed in DNA damage, viz., the p53 and p21 levels increased and p3BP1 foci formed. No visible change was observed in primary fibroblasts from the ataxia–telangiectasia patient. The results implicate ATM signaling in the fibroblast response to EWSMF.     

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.     

Influence of weak magnetic fields on fish retina photoreceptors

It has been shown for the first time that retina photoreceptors of the salmon Oncorhynchus masou (masu salmon) fry exposed to a constant magnetic field (80 Gs) in conditions of twilight illumination demonstrated not a twilight reaction, as in the control, but a darkness (scotopic) reaction. The pigment epithelium in this case reacted as to bright light. Under the influence of long wavelength red light, the retinomotor reaction corresponded to partial light adaptation. After the indemnification of the horizontal component (0.1 Gs) of the geomagnetic field, fish retina adapted to complete darkness demonstrated changes that could not be attributed to one of standard conditions of light exposure. Thus, the rods and cones demonstrated a reaction similar to that to twilight, double cones reacted as to complete darkness ("correct" reaction), and PE borrowed a position as at twilight. Apparently, the basic stimuli of the retina reactions were not light but changes of the magnetic field. Based on these results and the results available in literature, the authors offer a new variant of the hypothesis of light-dependent magnetoreception, which is based on the assumption that the liquid crystals of retina pigments are very sensitive receptors of magnetic field and do not require the presence of magnetite crystals. We assume that the layer of retina pigment epithelium participates in the complex process of transformation of a light signal, which takes into account the influence of magnetic field but not simply absorbs light superfluous for photoreceptors. The changes in magnetic field cause a distortion of the liquid crystal line structure of the pigment, which results in the transformation of the light signal acting on the photoreceptors. Monochromatic red light in the same way deforms the response to the native magnetic signal.     

A precision controlled environmental chamber for studies of the effects of electric fields on biological objects

An environmental chamber with associated control equipment for the study of possible effects of electric fields on biological objects (small mammals) is described in detail. Temperature is controlled within 0.4 C, relative humidity within ± 1.5 % and pressure below or above ambient is regulated to ± 1.0 mm Hg.Sound and electrical noise absorption by the chamber insulation is better than 90%.

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Zusammenfassung Eine Kammer mit dem zugehörigen KontrollgerÄt zum Studium der biologischen Wirkung von elektrischen Feldern an kleinen Versuchstieren wird ausführlich beschrieben.Die Temperatur ist innerhalb ±0,3C, die relative Feuchtigkeit innerhalb ± 1,5 % konstant und der Druck unterhalb oder oberhalb des Umgebungsdruckes auf ±1,0 mm Hg geregelt. Die LÄrmabsorption durch das Isolationsmaterial der Kammer ist über 90%.

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Resume On décrit ici en détails une chambre permettant l'étude des effets biologiques des champs électriques sur de petits mammifères. Cette chambre est assortie d'appareils de contrÔle. On peut y maintenir une température et une humidité constante (±0,3C, respectivement ±,1,5%) et la pression peut y Être réglée à volonté au-dessus et audessous de la pression ambiante avec une précision de ± 1,0 mm/Hg. L'absorption du bruit par le matériau d'isolation est supérieur à 90%.

     

The effects of weak extremely low frequency magnetic fields on calcium/calmodulin interactions.

Mechanisms by which weak electromagnetic fields may affect biological systems are of current interest because of their potential health effects. Lednev has proposed an ion parametric resonance hypothesis (Lednev, 1991, Bioelectromagnetics, 12:71-75), which predicts that when the ac, frequency of a combined dc-ac magnetic field equals the cyclotron frequency of calcium, the affinity of calcium for calcium-binding proteins such as calmodulin will be markedly affected. The present study evaluated Lednev's theory using two independent systems, each sensitive to changes in the affinity of calcium for calmodulin. One of the systems used was the calcium/calmodulin-dependent activation of myosin light chain kinase, a system similar to that previously used by Lednev. The other system monitored optical changes in the binding of a fluorescent peptide to the calcium/calmodulin complex. Each system was exposed to a 20.9 microT static field superimposed on a 20.9 microT sinusoidal field over a narrow frequency range centered at 16 Hz, the cyclotron frequency of the unhydrated calcium ion. In contrast to Lednev's predictions, no significant effect of combined dc-ac magnetic fields on calcium/calmodulin interactions was indicated in either experimental system.     

Biological effects of magnetic fields

The literature about the biological effects of magnetic fields is reviewed. We begin by discussing the weak and/or time variable fields, responsible for subtle changes in the circadian rhythms of superior animals, which are believed to be induced by same sort of "resonant mechanism". The safety issues related with the strong magnetic fields and gradients generated by clinical NMR magnets are then considered. The last portion summarizes the debate about the biological effects of strong and uniform magnetic fields.     

Biological effects due to weak electric and magnetic fields: the temperature variation threshold.

A large number of epidemiological and experimental studies suggest that prolonged (>100 s) weak 50-60-Hz electric and magnetic field (EMF) exposures may cause biological effects(NIEHS Working Group, NIH, 1998; Bersani, 1999). We show, however, that for typical temperature sensitivities of biochemical processes, realistic temperature variations during long exposures raise the threshold exposure by two to three orders of magnitude over a fundamental value, independent of the biophysical coupling mechanism. Temperature variations have been omitted in previous theoretical analyses of possible weak field effects, particularly stochastic resonance (Bezrukov and Vodyanoy 1997a. Nature. 385:319-321; Astumian et al., 1997 Nature. 338:632-633; Bezrukov and Vodyanoy, 1997b. Nature. 338:663; Dykman and McClintock, 1998. Nature. 391:344; McClintock, 1998;. Gammaitoni et al., 1998. Rev. Mod. Phys. 70:223-287). Although sensory systems usually respond to much shorter (approximately 1 s) exposures and can approach fundamental limits (Bialek, 1987 Annu. Rev. Biophys. Biophys. Chem. 16:455-468; Adair et al, 1998. Chaos. 8:576-587), our results significantly decrease the plausibility of effects for nonsensory biological systems due to prolonged, weak-field exposures.     

Sensitivity of the diamagnetic condensed matter to weak magnetic fields

It is shown that, under the influence of magnetic field, rotational moments of the same direction appear for all charged particles having the same sign of their charge and freely moving in a thermal fluctuational electromagnetic field in a diamagnetic condensed matter. The magnitude of this rotational moment is proportional to the thermal energy kT and can be substantially increased when the conditions for cyclotron resonance are satisfied. The moments of positively charged particles are directed oppositely to the vector of the magnetic field induction. The so-called "kT problem" has been solved. The evidence for magnetosensitivity is the appearance of rotational moments acting on the particles from the thermal field in the presence of an external magnetic field as a small factor.     

Effects of very weak magnetic fields on radical pair reformation

We can expect that biological responses to very weak ELF electromagnetic fields will be masked by thermal noise. However, the spin of electrons bound to biologically important molecules is not strongly coupled to the thermal bath, and the effects of the precession of those spins by external magnetic fields is not bounded by thermal noise. Hence, the known role of spin orientation in the recombination of radical pairs (RP) may constitute a mechanism for the biological effects of very weak fields. That recombination will generally take place only if the valence electrons in the two radicals are in a singlet state and the effect of the magnetic field is manifest through differential spin precessions that affect the occupation of that state. Because the spin relaxation times are of the order of microseconds, any effects must be largely independent of frequency up to values of a few megahertz. Using exact calculations on an appropriately general model system, we show that one can expect small, but significant, modifications of the recombination rate by a 50 microT field only under a narrow range of circumstances: the cage time during which the two elements are together must be exceptionally long--of the order of 50 ns or longer; the hyperfine field of either radical must not be so great as to generate a precession period greater than the cage containment time; and the characteristic recombination time of the radical pair in the singlet state must be about equal to the containment time. Thus, even under such singularly favorable conditions, fields as small as 5 microT (50 milligauss) cannot change the recombination rate by as much as 1%. Hence, we conclude that environmental magnetic fields much weaker than the earth's field cannot be expected to affect biology significantly by modifying radical pair recombination probabilities.