Effects Of Low-frequency Magnetic Fields Research Articles

Effect of low-frequency magnetic field (magnetic stimulation) and kinesitherapy on the level of selected blood parameters in haemodialysis patients

Effect of low-frequency magnetic field (magnetic stimulation) and kinesitherapy on the level of selected blood parameters in haemodialysis patients

Effects of low-frequency magnetic field on solubility, structural and functional properties of soy 11S globulin.

Soy 11S globulin has high thermal stability, limiting its application in the production of low-temperature gel foods. In this study, the low-frequency magnetic field (LF-MF, 5 mT) treatment (time, 30, 60, 90, and 120 min) was used to improve the solubility, conformation, physicochemical properties, surface characteristics, and gel properties of soy 11S globulin. Compared with the native soy 11S globulin, the sulfhydryl content, emulsifying capacity, gel strength, water-holding capacity, and absolute zeta potential values significantly increased (P < 0.05) after LF-MF treatment. The LF-MF treatment induced the unfolding of the protein structure and the fracture of disulfide bonds. The variations in solubility, foaming properties, viscosity, surface hydrophobicity, and rheological properties were closely related to the conformational changes of soy 11S globulin, with the optimum LF-MF modification time being 90 min. LF-MF treatment is an effective method to improve various functional properties of native soy 11S globulin, and this study provides a reference for the development of plant-based proteins in the food industry. © 2024 Society of Chemical Industry.

Formation and structural characteristics of pea globulin amyloid-like fibrils pretreated with low-frequency magnetic field

In this study, the effect of low-frequency magnetic field (LF-MF) on the formation and structural characteristics of pea globulin (PG) amyloid-like fibrils were investigated. The results showed that the structure of PG unfolded after LF-MF pretreatment. And PG pretreated with LF-MF (MPG) exhibited higher thioflavin T fluorescence intensity during the fibrillation compared with native PG (NPG), indicating that LF-MF could enhance the ability of PG to form amyloid-like fibrils. During the fibrillation process, the PG was hydrolyzed into small peptides in the initial stage of heating, leading to decreased particle size, as evidenced by the degraded subunits. The average particle size then increased with the small peptides aggregating, and the ordered amyloid-like fibrils with high content of β-sheets were formed. But the fibrils generated by MPG were larger in size and had a higher content of β-sheets. The formation of PG amyloid-like fibrils was confirmed by AFM images, and LF-MF pretreatment resulted in the generation of longer and thicker PG fibrils. The results of surface hydrophobicity showed that the hydrophobic interactions played an important role in the fibrillation process of PG. This work may provide a deep understanding about the effect of LF-MF on the assembly behavior and structural characteristics of PG amyloid-like fibrils.

Chronic-Exposure Low-Frequency Magnetic Fields (Magnetotherapy and Magnetic Stimulation) Influence Serum Serotonin Concentrations in Patients with Low Back Pain-Clinical Observation Study.

(1) Background: The influence of serotonin on many regulatory mechanisms has not been sufficiently studied. The use of a physical method, assuming the possibility of its action on increasing the concentration of serotonin, may be the direction of therapy limiting the number of antidepressants used. The aim of the research was to study the effects of low-frequency magnetic fields of different characteristics on the circadian profile of serotonin in men with low back pain. (2) Methods: 16 men with back pain syndrome participated in the study. The patients were divided into two groups. In group 1, magnetotherapy (2.9 mT, 40 Hz, square wave, bipolar) was applied at 10.00 a.m. In group 2, the M2P2 magnetic stimulation program of the Viofor JPS device was used. Treatments in each group lasted 3 weeks, 5 days each, with breaks for Saturday and Sunday. The daily serotonin profile was determined the day before the exposure and the day after the last treatment. Blood samples (at night with red light) were collected at 8:00, 12:00, 16:00, 24:00, and 4:00. The patients did not suffer from any chronic or acute disease and were not taking any medications. (3) Results: In group 1, a significant increase in serotonin concentration was observed after 15 treatments at 4:00. In group 2, a significant increase in serotonin concentration was observed at 8:00 after the end of the treatments. In comparison between magnetotherapy and magnetic stimulation, the time points at which differences appeared after the application of serotonin occurred due to the increase in its concentrations after the application of magnetic stimulation. (4) Conclusions: Magnetotherapy and magnetic stimulation, acting in a similar way, increase the concentration of serotonin. Weak magnetic fields work similarly to the stronger ones used in TMS. It is possible to use them in the treatment of mental disorders or other diseases with low serotonin concentrations.

Exploring the Inhibitory Effect of Low-frequency Magnetic Fields on Epileptiform Discharges in Juvenile Rat Hippocampus

Stimulation with a low frequency electromagnetic field (LF-EMF) has proven to represent a powerful method for the suppression of seizures, as demonstrated in select clinical and laboratory studies. However, the mechanism by which LF-EMF suppresses seizures remains unclear. The purpose of the present study was to explore the modulatory effect of LF-EMF on epileptiform discharges (EDs) using rat hippocampal slices and investigate the underlying mechanisms that mediate these effects. EDs in hippocampal slices was induced by magnesium-free (zero-Mg2+) artificial cerebrospinal fluid (ACSF) and recorded using an in vitro micro-electrode array (MEA). A small sub-decimeter coil was designed and incorporated in a flexible magnetic stimulation device that allowed electromagnetic fields with different parameters to be delivered to slices. After a stable ED event was recorded, magnetic fields of 0.5 Hz (30 min) with a magnetic intensity of 0.13 mT (5 Vpp voltage input) and 0.25 mT (20 Vpp voltage input) were applied. The results indicated that a high-amplitude 0.5 Hz magnetic field could lead to persistent suppression of ictal discharges (IDs), while low-amplitude magnetic fields did not influence IDs. The persistent suppression of complex ED was prevented if the magnetic fields were applied in the presence of 10 μmol/L bicuculline (BIC), a γ-aminobutyric acid type A (GABAA) receptor antagonist, while the application of BIC subsequent to a magnetic field application led to the reappearance of ID. The addition of BIC resulted in EDs that had previously been inhibited by magnetic fields, reappearing. Low-frequency magnetic stimulation was able to inhibit the conversion from interictal discharges (IIDs) or preictal discharges (PIDs) to IDs. This suppression was attributed to the modulation of GABAA receptor activity.

Biological autoluminescence as a noninvasive monitoring tool for chemical and physical modulation of oxidation in yeast cell culture

Normal or excessive oxidative metabolism in organisms is essential in physiological and pathophysiological processes, respectively. Therefore, monitoring of biological oxidative processes induced by the chemical or physical stimuli is nowadays of extreme importance due to the environment overloaded with various physicochemical factors. Current techniques typically require the addition of chemical labels or light illumination, which perturb the samples to be analyzed. Moreover, the current techniques are very demanding in terms of sample preparation and equipment. To alleviate these limitations, we propose a label-free monitoring tool of oxidation based on biological autoluminescence (BAL). We demonstrate this tool on Saccharomyces cerevisiae cell culture. We showed that BAL can be used to monitor chemical perturbation of yeast due to Fenton reagents initiated oxidation—the BAL intensity changes with hydrogen peroxide concentration in a dose-dependent manner. Furthermore, we also showed that BAL reflects the effects of low-frequency magnetic field on the yeast cell culture, where we observed a disturbance of the BAL kinetics in the exposed vs. control case. Our results contribute to the development of novel techniques for label-free, real-time, noninvasive monitoring of oxidative processes and approaches for their modulation.

Gel properties of grass carp myofibrillar protein modified by low-frequency magnetic field during two-stage water bath heating

The effects of low-frequency magnetic field (LF-MF) on the gel properties of grass carp myofibrillar proteins (GCMPs) and the underlying mechanisms were investigated to explore a better processing method for surimi gel products. GCMPs were untreated or treated with LF-MF of 9.5 mT in the first stage (40 °C heating for 50 min) or the second stage (85 °C heating for 40 min) of two-stage water bath heating. Results indicated that in the first stage, LF-MF induction may be detrimental to GCMPs unfolding and possibly resulted in a poor and unstable the GCMPs gels network structure, which had a negative effect on gel strength. Hence, water easily leaked from the GCMPs gel, leading to a decrease in WHC. Inversely, the unfolding of α-helix and the formation of random coil of LF-MF treatment in the second stage resulted in more exposure of internal groups, leading to the reduction of ionic bonds and increase of hydrogen bonds. These changed bonds further affected the T21 relaxation time, increased in PT2b and decreased in PT22, and mainly impacted the bind between water and protein, thus resulting in the improved gel strength and WHC.

Gel properties of myofibrillar proteins heated at different heating rates under a low-frequency magnetic field

The effects of low-frequency magnetic field combined with different heating rates on pork myofibrillar protein (MP) gels were investigated. Samples were treated under different heating rates (1 °C/min and 2 °C/min) in the presence or absence of 9.5 mT low-frequency magnetic field. The highest levels of intermolecular and intramolecular ionic and hydrogen bonds in MP were observed at the heating rate of 2 °C/min under the 9.5 mT magnetic field. These bonds resulted in decreasing the α-helix and increasing the β-sheet and β-turn, which promoted the formation of a more uniform microstructure. It also increased the proportion of bound water, increasing the ability of MP to bind with water. This effect, combined with the weaker hydrophobic interactions, as confirmed by the reduced content of tryptophan and aliphatic residues, explained well the high water-holding capacity of MP induced by heating at 2 °C/min under the 9.5 mT magnetic field.

Effect of low-frequency magnetic field on the gel properties of pork myofibrillar proteins

This study aimed to investigate the effect of a low-frequency magnetic field (LF-MF; 0, 0.25, 0.5, and 1.4 mT) on the gel properties of pork myofibrillar protein (MP) and to explore potential mechanisms. The water-holding capacity (WHC) and rheological properties of MP gels treated at 0.5 mT were better than those from other treatments. The water mobility did not change significantly as intensity increased, while the ratios of immobilized water (PT21) and free water (PT22) significantly decreased and increased, respectively. This suggested that the effect of LF-MF on MP hydration might be related to the formation of water clusters. Raman spectra suggested that α-helices unfolded and β-sheets, β-turns, and random coils were formed in MP gels (from 0.25 to 1.4 mT). Furthermore, the intensities of characteristic peaks in the tryptophan and aliphatic residues band were highest at 0.5 mT, indicating that 0.5 mT was the optimum intensity for hydrophobic interactions.

LF-MF inhibits iron metabolism and suppresses lung cancer through activation of P53-miR-34a-E2F1/E2F3 pathway

Our previous studies showed that low frequency magnetic fields (LF-MF) suppressed tumor growth and influenced the function of immune system. Nevertheless the mechanisms behind the effect of LF-MF still remain to be elucidated. In this study, Tumor- bearing mice subcutaneously inoculated with Lewis lung cancer cells were exposed to a LF-MF (0.4T, 7.5 Hz) for 35 days and Survival rate, tumor growth and the tumor markers were measured. Results showed that tumor growth was obviously inhibited with a prolonged survival of tumor- bearing mice by LF-MF exposure. In vitro experiments, LF-MF was found to induce cell growth arrest, cell senescence and inhibit iron metabolism of lung cancer cells. Moreover, LF-MF stabilized p53 protein via inhibiting cell iron metabolism and the stabilized p53 protein enhanced miR-34a transcription. Furthermore, increased expression of miR-34a induced cell proliferation inhibition, cell cycle arrest and cell senescence of lung cancer cells by targeting E2F1/E2F3. We also detected the relevant indicator in tumor tissue such as the iron content, the level of miR-34a and related protein, corresponding results were obtained. Taken together, these observations imply that LF-MF suppressed lung cancer via inhibiting cell iron metabolism, stabilizing p53 protein and activation P53- miR-34a-E2F1/E2F3 pathway.

The effects of low-frequency magnetic field exposure on the growth and biochemical parameters in lupin (Lupinus angustifolius L.)

The influence of frequent magnetic field stimulation (MFS) on plants is the subject of intense research. The effects of MFS on plants vary depending on its intensity, time of exposure or application form. The effects of low-frequency magnetic field in two doses, 0.2 mT, 16 Hz (MFS-1) and 0.2 mT, 50 Hz (MFS-2) on the mitotic activity and selected physiological and biochemical parameters in narrow-leafed lupin (Lupinus angustifolius L.) were evaluated. Non-exposed plants were used as control (C). It was noted that after the exposure of plants to MFS-1, the biometric parameters, mitotic activity, BSA and GPOX activity remained at the control level. However, a significant decrease in the assimilation pigment content was observed. On the other hand, the exposure of plants to MFS-2 was manifested by a decrease in the biometric parameters, mitotic activity and the assimilation pigment content, but an increase in GPOX activity in roots was noted.

Non-thermal extremely low frequency magnetic field effects on opioid related behaviors: Snails to humans, mechanisms to therapy.

In 1984, it was initially discovered in mice that an extremely low frequency magnetic field (ELF-MF) could attenuate opiate induced analgesia. In the past 30 years, we defined some of ELF-MF exposure and subject state conditions that can both increase and decrease nociception in snails and mice and can induce analgesia in humans. In our search for mechanisms and our desire to translate our findings to the treatment of chronic pain in humans, we pioneered the use of electroencephalography and magnetic resonance imaging to monitor effects during exposure. We have contributed to an understanding of the phenomena but a considerable amount remains to be done by us and those who have undertaken corroboratory and complimentary work. As the recipient of the 2013 d'Arsonval Award, I was invited to prepare an article for Bioelectromagnetics that highlights research findings that led to the award. Here, I have focused on our main findings associated with the effects of nociception of exposure to ELF-MF. To enrich the value of this contribution, I have put our research into the context of work of others. Further, I have suggested future directions of research and the potential for linkages and synergies associated with the extensive literature on animal orientation. Hence, it needs to be acknowledged that this is a report of our contributions and not intended as a balanced review.

Effect of low-frequency magnetic field on formation of pigments of Monascus purpureus

Monascus purpureus is a key fungus used to produce food pigments from secondary metabolites. Low-frequency magnetic field (LF-MF) affects production of M. purpureus secondary metabolites as one of the cultivation environments. The objective of this study was to measure optimum strength of induced magnetic field and duration of exposure for yellow and red pigment production of M. purpureus in solid-state fermentation. There was a 65.4 and 59.2 % increase in peak yield of yellow and red pigments compared to the control when the treatments were exposed to a magnetic field induction at 0.4 mT on the 8–9th day of incubation time. From kinetics of yellow and red pigment production, yield of yellow and red pigments was significantly increased in the samples exposed to magnetic field from the 8th to 11th day compared with that of the control group. LF-MF could increase the production rates of yellow pigments from 221.25 to 381.75 and red pigments from 165.00 to 292.50 U/g day. It could also significantly prolong the quickly generate time of yellow pigment. The appropriate magnetic field treatment could increase the efficiency of yellow and red pigment production.

Nanomechanical control of the activity of enzymes immobilized on single-domain magnetic nanoparticles

Analytical and numerical methods are used to analyze the main regularities of deformation of biologically active molecules caused by the nonthermal effect of low-frequency magnetic field on single-domain magnetic nanoparticles to the surfaces of which the macromolecules are chemically bound.

Spin biochemistry modulates reactive oxygen species (ROS) production by radio frequency magnetic fields.

The effects of weak magnetic fields on the biological production of reactive oxygen species (ROS) from intracellular superoxide (O2 •−) and extracellular hydrogen peroxide (H2O2) were investigated in vitro with rat pulmonary arterial smooth muscle cells (rPASMC). A decrease in O2 •− and an increase in H2O2 concentrations were observed in the presence of a 7 MHz radio frequency (RF) at 10 μTRMS and static 45 μT magnetic fields. We propose that O2 •− and H2O2 production in some metabolic processes occur through singlet-triplet modulation of semiquinone flavin (FADH•) enzymes and O2 •− spin-correlated radical pairs. Spin-radical pair products are modulated by the 7 MHz RF magnetic fields that presumably decouple flavin hyperfine interactions during spin coherence. RF flavin hyperfine decoupling results in an increase of H2O2 singlet state products, which creates cellular oxidative stress and acts as a secondary messenger that affects cellular proliferation. This study demonstrates the interplay between O2 •− and H2O2 production when influenced by RF magnetic fields and underscores the subtle effects of low-frequency magnetic fields on oxidative metabolism, ROS signaling, and cellular growth.

The influence of application of a low-frequency magnetic field on the serum corticosterone level (an experimental study)

The results of analysis of the literature publications suggest the necessity of experimental studies aimed at investigation of modulating effect of low-frequency magnetic fields on endocrine organs. The present study was carried out using 200 outbred white male rats (body weight 200-220 g). Corticosterone was measured in blood sera following the application of a low-frequency magnetic field (20 and 53 Hz with induction from 0.4 to 6 mT) generated by a Mini-Expert-T apparatus for induction magnetic therapy during 30 minutes. It was shown that the application of the alternating magnetic field to the adrenal region of the rats in the selected frequency and induction ranges caused a significant increase in the serum corticosterone levels. The results of the present study on the hormonal activity of rat adrenals give reason to consider the influence of the alternating magnetic fields as being modulatory. Analysis of the data thus obtained has demonstrated the non-linear dependence of glucocorticoid activity of the rat adrenal glands on the induction strength of the alternating magnetic field.

Study of the effect of low-frequency magnetic fields on biological objects

One of the possible approaches on modeling of the magnetotherapeutic effects on biological objects is considered, using water as an example. Experimental data of the water pH changes depending on the effect of the magnetic field and the environment parameters are

Involvement of midkine expression in the inhibitory effects of low-frequency magnetic fields on cancer cells.

Effects of magnetic fields (MFs) on cancer cells may depend on cell type and exposure conditions. Gene expression levels are different among cancer cells. However, the effect of MFs on cancer cells with different gene expressions is still unclear. In this study, the cancer cell lines BGC-823, MKN-45, MKN-28, A549, SPC-A1, and LOVO were exposed to a low-frequency MF. Specific parameters of MFs were determined. Furthermore, the potential of the MF to influence cancer cell growth with midkine (MK) expression was evaluated. Cell proliferation and cell cycle were detected using the CCK-8 assay and flow cytometry. Cell ultrastructure was observed by transmission electron microscopy. BGC-823 cells with over-expression of MK (BGC-MK cells) and stanniocalcin-1 were generated by plasmid construction and transfection. Results showed that exposure to a 0.4-T, 7.5 Hz MF inhibited the proliferation of BGC-823, MKN-28, A549, and LOVO cells, but not MKN-45 and SPC-A1 cells. Moreover, the inhibitory effect of the MF on BGC-MK cells was lower (12.3%) than that of BGC-823 cells (20.3%). Analysis of the cell cycle showed that exposure to the MF led to a significant increase in the S phase in BGC-823 cells, but not in BGC-MK cells. In addition, organelle morphology was modified in BGC-823 cells exposed to the MF. These results suggest that exposure to a 0.4-T, 7.5 Hz MF could inhibit tumor cell proliferation and disturb the cell cycle. The alteration of MK expression in cancer cells may be related to the inhibitory effect of the MF on these cells.

Extremely low frequency magnetic field effects on metabolite of Aspergillus niger

The effect of the extremely low frequency (ELF) magnetic field on citric acid and cellulase production by Aspergillus niger using liquid Charles culture medium was studied during shake flask culture. The cellular suspension was exposed to a magnetic field (t = 4 h, B = 1 mT, and f = 50 Hz). The dependence of yield of citric acid and activity of cellulase on time of exposure and on the value of the magnetic field induction B was measured. Both yield of citric acid and activity of cellulase increased with increasing exposure time and/or induction B, but the quantity of the effect was dependent on the chemical structure of metabolites. The metabolism of citric acid was more sensitive to the magnetic field than that of cellulase. From the measurement of the metabolism dynamics we concluded that the increase in the citric acid and activity of cellulase started immediately after the magnetic field was switched on.

Effect of low-frequency magnetic field on microstructures and macrosegregation of horizontal direct chill casting 7075 aluminum alloy

The horizontal direct chill (HDC) casting process is a well-established production route for an aluminum alloy ingot; however, the ingot may suffer from inhomogeneous microstructures and serious macrosegregation due to the unbalanced cooling condition and gravitational effect. In order to control the defect, a low frequency electromagnetic field has been applied in the HDC casting process and its influences on cast surface, microstructures and macrosegregation have been studied. The results show that the low frequency electromagnetic field can effectively improve surface quality, reduce inhomogeneous microstructures and macrosegregation in HDC product; and two main parameters of the electromagnetic field—density and frequency, significantly influence the microstructures and solution distribution along the diameter of the ingot. In the range of ampere-turns and frequency employed in the experiments, the optimum ampere-turns and frequency are found to be 10,000 At, 30 Hz.