The role of lipid peroxidation and myeloperoxidase in priming a respiratory burst in neutrophils under the action of combined constant and alternating magnetic fields

The enhancement of lipid peroxidation in neutrophils (the content of malonic dialdehyde increased by 10.2%) has been shown after a 1-h exposure to a combined constant (42 μT) magnetic field and a weak low-frequency magnetic field (1.0, 4.4, and 16.5 Hz; 860 nT) collinear to it. No correlation was found between this effect and the process of functional pre-activation (priming) of neutrophils as a result of the combined action of magnetic fields detected by chemiluminescence enhancement in response to the introduction of the bacterial peptide N-formyl–Met–Leu–Phe in the presence of luminol, since ionol (10 μM), an inhibitor of lipid peroxidation, did not reduce the neutrophil priming index in this case. Preliminary addition of histidine (0.1 and 1.0 mM), a singlet oxygen scavenger, also did not decrease the priming index. A myeloperoxidase inhibitor, sodium azide (0.1 mM), exerted a significant inhibitory effect on the chemiluminescence intensity of the neutrophil suspension; priming did not develop in the presence of this inhibitor after the action of combined magnetic fields.     

Molecular mechanism of effect of rotating constant magnetic field on organisms

The effect of RCMF-magnetic therapy apparatus on signal substances was studied. The radioimmunoassay (RIA) suggested that the magnetic field increased p-endorphin markedly in plasma. ELISA indicated that the magnetic field inhibited vomiting reaction induced by chemotherapy drug, with reversible decrease of serotonin (5-HT) level in brains, small intestine tissue and serum. Furthermore, the bioeffect of magnetic fields on 5-HT level presented a typical window effect and post-effect, and the inhibitory effect of magnetic field on the emesis was parallel to the decrease level of 5-HT. This result implied that the decrease of 5-HT might be the basis of rotating constant magnetic field (RCMF) inhibiting drug-induced emesis. The nitric acid reductase-spec-trophotometry and nicotinamide adenine dinucleotide-diaphorase/arginine-vasopressin (AVP) cytochemistry technique showed that the magnetic field induced nitric oxide (NO) increase in hypo-thalamus and the high NO(A) level lasted for 3 hours. The results sugg     

A human source for ELF magnetic perturbations

ABSTRACT

Current models that frame consciousness in terms of electromagnetic field theory carry implications that have yet to be fully explored. Endogenous weak extremely low frequency (ELF) magnetic fields are generated by ionic charge flow in axons, dendrites and synaptic transmitters. Because neural tissues are transparent to such fields, these provide the basis for the globally unifying qualities required to properly describe consciousness as a field. At the same time, however, an electromagnetic approach predicts partial transmission of this 1–100 nT field, suggesting external interactions similar to the various ELF magnetic perturbations that are linked to homeostatic and endocrine-related physiological effects. It follows that humans may represent an additional, previously unrecognized source of weak (1–10 nT) ambient ELF magnetic fields.     

Molecular mechanism of effect of rotating constant magnetic field on organisms

The effect of RCMF-magnetic therapy apparatus on signal substances was studied. The radioimmunoassay (RIA) suggested that the magnetic field increased β-endorphin markedly in plasma. ELISA indicated that the magnetic field inhibited vomiting reaction induced by chemotherapy drug, with reversible decrease of serotonin (5-HT) level in brains, small intestine tissue and serum. Furthermore, the bioeffect of magnetic fields on 5-HT level presented a typical window effect and post-effect, and the inhibitory effect of magnetic field on the emesis was parallel to the decrease level of 5-HT. This result implied that the decrease of 5-HT might be the basis of rotating constant magnetic field (RCMF) inhibiting drug-induced emesis. The nitric acid reductase-spectrophotometry and nicotinamide adenine dinucleotide-diaphorase/arginine-vasopressin (AVP) cytochemistry technique showed that the magnetic field induced nitric oxide (NO) increase in hypothalamus and the high NO(A) level lasted for 3 hours. The results suggested that NO(A) increases after the treatment of the magnetic field in hypothalamus, which may result from strong expression of NO-ergic neuron in paraventricular hypothalamic nucleus (PVN), periventricular hypothalamic nucleus (PEN) and supraoptic nucleus (SON). The coexistence of NO and AVP may play an important role in the regulation of endocrine and neuroendocrine by the magnetic field. And our data also confirmed that the magnetic field increased the content of NO so strongly that high NO level lasted for 3 hours, also made neuropeptide Y (NPY) cell in medulla stained heavily.     

Effects of a homogeneous magnetic field on erythrocyte sedimentation and aggregation

Effects of a homogeneous static magnetic field on erythrocyte sedimentation rate (ESR) have been assessed by using the standard Westergren method. A magnetic field of 6.3 T in the vertical direction only slightly enhanced ESR in saline solution, which was consistent with an effect on cell orientation. On the other hand, the magnetic field greatly enhanced ESR in plasma. It took a long time (about 20 min) for an ESR change to occur in plasma in response to the magnetic field. The effects in plasma were too large to originate only from cell orientation and were clearly distinct from a magnetic field-induced Boycott effect under an inhomogeneous magnetic field. A morphological examination and the nonlinear time course of the sedimentation in plasma indicated that the magnetic field increased cell aggregation and thereby enhanced ESR in plasma. Bioelectromagnetics 18:215–222, 1997. © 1997 Wiley-Liss, Inc.     

Exposure to inhomogeneous static magnetic field ceases mechanical allodynia in neuropathic pain in mice

Magnetic therapy as a self‐care intervention has led to the conduct of numerous human trials and animal experiments. Results concerning the analgesic efficacy of magnetic exposure, however, are inconsistent. By using a magnetic device generating an inhomogeneous static magnetic field (iSMF), here we studied how the whole‐body exposure to iSMF may influence the mechanical withdrawal threshold (MWT) of the hind paw in different stages of neuropathic pain evoked by partial ligation of the sciatic nerve in mice. It was found that iSMF exposure did not prevent the decrease of MWT in the first postoperative week. A 2‐week long iSMF treatment that was started just after the nerve ligation elevated MWT values to a modest extent. However, the effectiveness of a daily exposure to iSMF was much more prominent when it was applied between postoperative days 15 and 28. In this case, MWT was already noticeably increased after the first treatment and it practically reached the control values by the end of the 2‐week long exposure period. The results suggest that exposure to iSMF cannot prevent the development of mechanical allodynia, but can inhibit processes that maintain the increased sensitivity to mechanical stimuli in neuropathic pain. Bioelectromagnetics 30:438–445, 2009. © 2009 Wiley‐Liss, Inc.     

The Effect of ELF Magnetic Field on Tumor Growth after Electrochemotherapy

From a fundamental point of view, chemotherapy is the most widely used treatment for cancers despite its side effects on normal cells and tissues. Electrochemotherapy (ECT) is a method for increasing the permeability of cancer cells to drugs and, hence, decreasing their dosage. It apparently creates electropores on the cell membrane using electric pulses. ECT can decrease tumor volume; but this effect is not permanent, and partial regrowth has been reported. The aim of this study was to investigate the potential of magnetic fields in preventing the regrowth of tumors after ECT. Tumoral Balb/c mice were exposed to a magnetic field (15 mT, 50 Hz) for 12 days after treating additionally with 70 V/cm electric pulses and bleomycin at the first day. The magnetic field caused a significant reduction in tumor volumes, while there was no significant difference between the ECT and the electroporation with ECT and magnetic field groups. The exploited magnetic field (15 mT, 50 Hz) could decrease the tumor growth rate significantly, without any effect on ECT efficiency.     

Influence of the magnetic fields on frog sciatic nerve

The constant magnetic field (1000–7120 gauss) was applied to previously stimulated frog sciatic nerve. The following was observed : a) There is no instantaneous effect of either parallel or perpendicular magnetic field on compound action potential amplitude. b) Parallel magnetic field of 1000–7120 gauss does not change the amplitude of compound action potential significantly with time. c) When perpendicular magnetic field was applied to the nerve, an increase in the amplitude of compound action potential was observed, which can mean that the nerve exhibits some sort of magnetic anisotropy.     

A Decrease of the Respiratory Burst in Neutrophils after Exposure to Weak Combined Magnetic Fields of a Certain Duration

Biophysics - Abstract—A significant decrease in the respiratory burst activity of a neutrophil suspension has been recorded in response to N-formyl–Met–Leu–Phe peptide...     

Distribution of erythrocyte in a model vessel exposed to inhomogeneous magnetic fields

In order to investigate magnetic field effects on blood flow, changes in the flow of erythrocytes in a model branched vessel were observed in an inhomogeneous magnetic field. The magnetic field was applied perpendicular to the straight vessel before branching. When the suspension containing paramagnetic erythrocytes with high spin methemoglobin or deoxygenated hemoglobin flowed in the model vessel, the erythrocytes were attracted towards the stronger magnetic field (i.e. to the side branch) and an excess flow of erythrocytes to the side branch was detected. This excess flow of erythrocytes to the side branch was the highest at a hematocrit of about 5% for the suspension containing erythrocytes with high spin methemoglobin. In the case of mixed suspensions containing erythrocytes with high spin methemoglobin and oxygenated erythrocytes, the excess flow of erythrocytes to the side branch reached its maximum at the "partial hematocrit" for the paramagnetic erythrocyte of around 5% and remained nearly constant with a further increase of the "partial hematocrit." The effect of magnetic field decreased as the flow velocity increased. These results are explained with the paramagnetism of erythrocytes and with the assumption of a hydrodynamic interaction among erythrocytes which are pulled in the direction of the magnetic field. It is suggested that a strong inhomogeneous magnetic field is not totally negligible to the blood circulation.     

Tolerance to morphine-induced analgesia in mice: Magnetic fields function as environmental specific cues and reduce tolerance development

Mice receiving daily injection of morphine (10 mg/kg) developed tolerance to morphine-induced analgesia, such that after 5–7 days of treatment their thermal response (paw licking) latencies in the hot plate test were indistinguishable from those of control animals. Exposure to a rotating magnetic field for thirty minutes before the daily morphine administrations significantly reduced the development of tolerance. These magnetic exposure also significantly increased over 7–10 days the basal nociceptive thresholds and paw licking response latencies of saline treated mice. Control and sham exposed mice that were fully tolerant to the analgesic effects of morphine failed to show any tolerance to morphine-induced analgesia when exposed to the magnetic stimuli prior to injection. Likewise, the partial tolerance to morphine shown by mice exposed to the rotating magnetic field pre-injection environmental cues was eliminated when control or sham pre-injection cues lacking the magnetic stimuli were provided. In all cases tolerance to morphine-induced analgesia was evident in the subsequent re-test with the original cues. These results indicate that magnetic field exposure can reduce the development of tolerance to the analgesic effects of morphine. They also show that magnetic stimuli function as significant environmental cues for the development of tolerance to morphine-induced analgesia. This suggests that magnetic stimuli affect both the associative (classical conditioning) and non-associative (physiological, pharmacological) mechanisms involved in the development of opiate tolerance.     

The role of hydroxyl radicals and calcium ions in the priming of a respiratory burst in neutrophils and the increase in luminol-dependent blood chemiluminescence on exposure to combined magnetic fields with a very weak low-frequency alternating component

The intracellular calcium chelator 1,2-bis(2-aminophenoxy)ethane N,N,N′,N′-tetraacetic acid acetoxymethyl ester (BAPTA AM) used at low concentrations (1.0 and 2.5 μM) was shown to block the priming effect of weak combined static (42 μT) and low-frequency collinear alternating (1.0, 4.4, and 16.5 Hz; 0.86 μT) magnetic fields. This blockage was inferred from a greater increase in chemiluminescence observed for a mouse neutrophil suspension exposed to combined magnetic fields in response to the bacterial peptide N-formyl–Met–Leu–Phe added in the presence of luminol. Similar results were obtained for the effect of BAPTA AM on luminol-dependent chemiluminescence of whole blood. The priming effect of weak combined magnetic fields on the respiratory burst in neutrophils did not depend on the presence of extracellular Ca²⁺ and was not affected by the hydroxyl radical scavenger dimethyl sulfoxide used at 0.025–1.0 mM.     

Teratological assessment of exposure to time-varying magnetic field

A teratological assessment was performed using rats that were exposed to an alternating magnetic field. The magnetic field had a sawtooth waveform similar to that produced by video display terminals (VDTs). Female rats were exposed 2 weeks prior to and throughout pregnancy at a rate of 7 h/day. Three intensities of magnetic field (5.7, 23 or 66 microT) were used. All of these field intensities were much greater than those to which VDT users are exposed. A slight but statistically significant decrease in maternal lymphocyte count for the highest intensity field was found as compared with the control group. However, the lymphocyte count was within the normal range, and the observed changes in hematological parameters were considered mild. No other maternal or fetal parameters that were examined showed a significant difference for any of the three field intensities. Where minor variations in skeleton development were observed they were known to be the common "noise" that appears in every teratological evaluation.     

Effects of exposure to a circularly polarized 50-Hz magnetic field on plasma and pineal melatonin levels in rats

We sought to determine whether a 6-week exposure to a 50-Hz rotating magnetic field influences melatonin synthesis by 11–18 week-old Wistar-King male rats. Rats were exposed continuously to a rotating magnetic field at 1, 5, 50, or 250 μT (spatial vector rms) for 6 weeks, except for twice-weekly breaks of about 2 h for cleaning of cages and feeding. The rats were housed in exposure and sham-exposure facilities, which were located in the same room, under a 12:12 light-dark photoperiod (lights on at 06:00 h). The room was constantly illuminated by 4 small, dim red lights (< 0.07 lux in dark period). Levels of plasma and pineal gland melatonin were determined by radioimmunoassay. A significant decrease of melatonin was observed between the control group and groups exposed to a magnetic field at a flux density in excess of l μT during the night time, but no statistical differences were found among the exposed groups. These results indicate that subchronic exposure of albino rats to a 50-Hz rotating magnetic field influences melatonin production and secretion by the pineal gland. © 1993 Wiley-Liss, Inc.     

Effect of alternating magnetic field on ontogenesis and morphophysiological characteristics of radish plants of different magnetic orientation

Effect of weak horizontal alternating magnetic field (AMF) with a frequency of 50 Hz and intensity of 400 A/m on seed formation and morphophysiological characteristics was investigated in radish (Raphanus sativus L.) plants of major types of magnetic orientation (TMO): North–South (NS) and West–East (WE). AMF retarded the passage through all the stages of ontogenesis; as compared with control material, the next leaves emerged slower, and the transition to formation of flower-bearing stems, budding, flowering, and production of pods and mature seeds was delayed. In plants of NS TMO exposed to AMP, the number of pods and seeds and the weight of seeds decreased, while these characteristics rose in WE TMO. AMF acted as an environmental factor differentiating plants’ response depending on their type of magnetic orientation. Dissimilar response to the magnetic field is associated with their physiological status.     

Magnetic field-induced increase of the yield of (bacterio)chlorophyll emission of some photosynthetic bacteria and of Chlorella vulgaris

In photosynthetic bacteria, in which the iron-ubiquinone complex X is prereduced, a magnetic field induces an increase of the emission yield, which is correlated with the decrease in reaction center triplet yield reported previously (Hoff, A.J., Rademaker, H., van Grondelle, R. and Duysens, L.N.M. (1977) Biochim. Biophys. Acta 460, 547–554). Our results support the hypothesis that under these conditions charge recombination of the oxidized primary donor and the reduced primary acceptor predominantly generates the excited singlet state of the reaction center bacteriochlorophyll.In Chlorella vulgaris and spinach chloroplasts, at 120 K, the magnetic field has an effect similar to that found in bacteria, which suggests that an intermediary electron acceptor between P-680 and Q is present in Photosystem II also.     

Effects of 45-Hz magnetic fields on the functional state of the human brain

The influence of sinusoidal 45-Hz magnetic fields on the brain functions of 20 volunteers was investigated in a double-blind study using spectral analysis of EEG and measurements of Omega potentials and reaction time (RT). The field strength was 1,000 A/m (1.26 mT) and the duration of exposure was 1 h. Ten volunteers were exposed to a continuous field and ten received an intermittent exposure (1 s on/1 s off). Each person received one real and one sham exposure. One half of the volunteers got the real exposure first and the sham treatment after at least 24 h. For the rest, the sequence was inverse. The measurements of EEG, omega potentials and RT were performed before and after each exposure. Several statistically significant changes were observed, most of them after intermittent exposure. In the EEG, an increase of alpha (7.6–13.9 Hz) activity and a decrease of delta (1.5–3.9 Hz) activity were observed. β waves (14.2–20 Hz) increased in the frontal derivations as did the total power in occipital derivations. The mean and peak frequencies of EEG increased mainly in the frontal derivations. No direct effects on RT were seen. Learning to perform the RT test (decrease of RT in repeated trials), however, seemed to be affected by the exposure. The persons who received real exposure first learned more slowly than those who got sham exposure first. Further experiments are necessary to confirm the findings and for understanding the mechanisms of the effects. © 1993 Wiley-Liss. Inc.     

Measurement of magnetic field in dentistry

The principal objective was to measure the magnetic fields occurring in dental surgeries at simultaneous subtraction of direct ground component of the magnetic field. A specifically designed instrument with the Hall probe was used for the measurement. It consisted of two amplifiers and a low frequency filter. Its task was to measure mean square values of the field (RMS) dependent on the position in space. Qualitative and quantitative analyses of the investigated variables enabled making conclusions about the magnetic fields in dental surgeries. A number of studies have shown that many dental instruments produce radiation with magnetic field higher than 40 G, at a significant decrease in power of the magnetic field with increasing distance from the source. It has also been reported that instruments of older generations produce stronger magnetic fields than do the new ones.     

Influence of a Permanent Magnetic Field on the Composition and Content of Sugars in Leaves and Storage Roots of Radish Plants of Major Types of Magnetic Orientation

The influence of a weak permanent magnetic field (PMF) with a strength of 400 A/m on the composition and content of sugars was investigated in radish (Raphanus sativus L.) leaves and storage roots of the two major types of magnetic orientation (TMO): North–South (NS TMO) and West–East (WE TMO). Plants were grown in spring and autumn in a greenhouse of the Institute of Plant Physiology, Russian Academy of Sciences. The weak PMF changed the total sugar content in the leaves and storage roots of radish depending on the belonging of the radish plants to the NS or WE type of magnetic orientation, the growing season, and age of plants and the plant organ. The PMF was an environmentally significant factor, since radish plants of different types of magnetic orientation (NS and WE) had a different reaction to the effect of the field related to the peculiarities of their physiological status.     

Decreased Production of the Superoxide Anion Radical in Neutrophils Exposed to a Near-Null Magnetic Field

Biophysics - This paper reports that pre-incubation of a neutrophil suspension in the presence of a near-null magnetic field produced using a system of magnetic shields (a residual constant...