Reactive oxygen species (ROS) production in human peripheral blood neutrophils exposed in vitro to static magnetic field

The aim of this study was to determine the effect of gradient static magnetic field (SMF) on reactive oxygen species (ROS) production in human neutrophils in peripheral blood in vitro. Blood samples collected from healthy individuals were incubated in an inhomogeneous SMF (in a south or north pole of the field) for 15, 30 or 45 minutes. The maximum value of induction (B _max) amounted to ≈ 60 mT. To determine the strength of the ROS production, dihydrorhodamine (123DHR) as fluorophore and phorbol 12-myristate 13-acetate (PMA) as respiratory burst stimulator were used. 123DHR oxidation by ROS was measured by flow cytometry. The exposure of blood samples to SMF induced statistically significant changes in ROS production in unstimulated and PMA-stimulated neutrophils. The observed effects were highly correlated with the exposure time and depended on the orientation of the field. Although intracellular mechanisms underlying such interactions are not thoroughly understood, it could be presumed that SMF affects ROS metabolic oscillations and their formation and inactivation. This study emphasizes the importance of proper adjustment of exposure time to SMF for any potential therapeutic applications.     

Effect of static magnetic field on morphology and growth metabolism of Flavobacterium sp. m1-14

Increasing evidence shows that static magnetic fields (SMFs) can affect microbial growth metabolism, but the specific mechanism is still unclear. In this study, we have investigated the effect of moderate-strength SMFs on growth and vitamin K₂ biosynthesis of Flavobacterium sp. m1-14. First, we designed a series of different moderate-strength magnetic field intensities (0, 50, 100, 150, 190 mT) and exposure times (0, 24, 48, 72, 120 h). With the optimization of static magnetic field intensity and exposure time, biomass and vitamin K₂ production significantly increased compared to control. The maximum vitamin K₂ concentration and biomass were achieved when exposed to 100 mT SMF for 48 h; compared with the control group, they increased by 71.3% and 86.8%, respectively. Interestingly, it was found that both the cell viability and morphology changed significantly after SMF treatment. Second, the adenosine triphosphate (ATP) and glucose-6-phosphate dehydrogenase (G6PDH) metabolism is more vigorous after exposed to 100 mT SMF. This change affects the cell energy metabolism and fermentation behavior, and may partially explain the changes in bacterial biomass and vitamin K₂ production. The results show that moderate-strength SMFs may be a promising method to promote bacterial growth and secondary metabolite synthesis.

     

The effect of 100 mT SMF on activation of the hsp70 promoter in a heat shock/luciferase reporter system

Human exposure to magnetic fields, increased through use of new technologies like magnetic resonance imaging (MRI), has prompted investigations into possible effects of static magnetic fields (SMFs) on cellular processes. However, controversy still remains between many studies, which likely results from a lack of uniformity across experimental parameters, including the length of magnetic field exposure, the strength of the magnetic field, and the cell type or organism under investigation. The purpose of this research was to monitor effects of SMF exposure using real‐time luminescence photometry. The study investigated the potential interaction of a 100 mT SMF on a heat shock protein (hsp70)/luciferase reporter construct in stably transfected NIH3T3 cells. Changes in heat shock promoter activation following 100 mT SMF exposure were analyzed and detected as bioluminescence in real‐time. Two heat parameters were considered in combination with sham‐ and 100 mT‐exposed experiments: no heat or 1,800 s heat. As expected, there was a significant increase in bioluminescence in response to 1,800 s of heat alone. However, no significant difference in average hsp70 promoter activation between sham and 100 mT experiments was observed for no heat or 1,800 s heat experiments. Therefore, a 100 mT SMF was shown to have no effect on the activation of the heat shock protein promoter during SMF exposure or when SMF exposure was combined with a heat insult. J. Cell. Biochem. 108: 956–962, 2009. © 2009 Wiley‐Liss, Inc.     

Cognitive effects of head-movements in stray fields generated by a 7 Tesla whole-body MRI magnet

The study investigates the impact of exposure to the stray magnetic field of a whole-body 7 T MRI scanner on neurobehavioral performance and cognition. Twenty seven volunteers completed four sessions, which exposed them to approximately 1600 mT (twice), 800 mT and negligible static field exposure. The order of exposure was assigned at random and was masked by placing volunteers in a tent to hide their position relative to the magnet bore. Volunteers completed a test battery assessing auditory working memory, eye-hand co-ordination, and visual perception. During three sessions the volunteers were instructed to complete a series of standardized head movements to generate additional time-varying fields ( approximately 300 and approximately 150 mT.s(-1) r.m.s.). In one session, volunteers were instructed to keep their heads as stable as possible. Performance on a visual tracking task was negatively influenced (P<.01) by 1.3% per 100 mT exposure. Furthermore, there was a trend for performance on two cognitive-motor tests to be decreased (P<.10). No effects were observed on working memory. Taken together with results of earlier studies, these results suggest that there are effects on visual perception and hand-eye co-ordination, but these are weak and variable between studies. The magnitude of these effects may depend on the magnitude of time-varying fields and not so much on the static field. While this study did not include exposure above 1.6 T, it suggests that use of strong magnetic fields is not a significant confounder in fMRI studies of cognitive function. Future work should further assess whether ultra-high field may impair performance of employees working in the vicinity of these magnets.     

Static magnetic field effect on the arterial baroreflex-mediated control of microcirculation: implications for cardiovascular effects due to environmental magnetic fields

Increasing evidence suggests that time-varying and static magnetic fields in the environment might affect the cardiovascular system. To explore the underlying physiology, the effect of static magnetic fields (SMFs) on the carotid baroreflex control of microcirculation was studied. Twenty-four hemodynamic monitorings were performed in rabbits sedated by pentobarbital infusion (5 mg/kg/h) during experiments that lasted 120 min. Mean femoral artery blood pressure, heart rate, and ear lobe skin microcirculatory blood flow, measured by microphotoelectric plethysmogram (MPPG), were simultaneously recorded before and after a 40 min exposure of the sinocarotid baroreceptors to Nd₂–Fe₁₄–B alloy magnets (n = 14) or sham magnets (n = 10, control series). The local SMF field was 350 mT, at the baroreceptors’ site. Arterial baroreflex sensitivity (BRS) was estimated from heart rate/blood pressure response to intravenous bolus injections of nitroprusside and phenylephrine. A significant positive correlation was found between the SMF-induced increase in BRS (ΔBRS = BRS_afterSMF − BRS_priorSMF) and the increment in microvascular blood flow (ΔMPPG = MPPG_afterSMF − MPPG_priorSMF) (r = 0.66, p < 0.009). The SMF probably modulated the arterial baroreflex-mediated microcirculatory control. This could represent one possible mechanism how environmental magnetic fields act on the cardiovascular system, and a method how to complexly adjust macro- and microcirculation with potential clinical implementation.     

Lateral gradients significantly enhance static magnetic field‐induced inhibition of pain responses in mice—a double blind experimental study

Recent research demonstrated that exposure of mice to both inhomogeneous (3–477 mT) and homogeneous (145 mT) static magnetic fields (SMF) generated an analgesic effect toward visceral pain elicited by the intraperitoneal injection of 0.6% acetic acid. In the present work, we investigated behavioral responses such as writhing, entry avoidance, and site preference with the help of a specially designed cage that partially protruded into either the homogeneous (ho) or inhomogeneous (inh) SMF. Aversive effects, cognitive recognition of analgesia, and social behavior governed mice in their free locomotion between SMF and sham sides. The inhibition of pain response (I) for the 0–5, 6–20, and 21–30 min periods following the challenge was calculated by the formula I = 100 (1 ? x/y) in %, where x and y represent the number of writhings in the SMF and sham sides, respectively. In accordance with previous measurements, an analgesic effect was induced in exposed mice (I_ho = 64%, P < 0.0002 and I_inh = 62%, P < 0.002). No significant difference was found in the site preference (SMF_{ho, inh} vs. sham) indicating that SMF is neither aversive nor favorable. Comparison of writhings observed in the sham versus SMF side of the cage revealed that SMF exposure resulted in significantly fewer writhings than sham (I_ho = 64%, P < 0.004 and I_inh = 81%, P < 0.03). Deeper statistical analysis clarified that the lateral SMF gradient between SMF and sham sides could be responsible for most of the analgesic effect (I_ho = 91%, P < 0.02 and I_inh = 54%, P < 0.02). Bioelectromagnetics 34:385–396, 2013. © 2012 Wiley Periodicals, Inc.     

Chronic exposure to a 2 mT static magnetic field affects the morphology,the metabolism and the function of in vitro cultured swine granulosa cells

In recent years, the exposure of organisms to static magnetic fields (SMFs) is continuously increasing. Thus, we investigated the effect of chronic exposure to a 2 mT SMF on in vitro cultured swine granulosa cells (GCs). In particular, the culture expansion (cell viability and doubling time), the cell phenotype (cell morphology and orientation, actin and α-tubulin cytoskeleton), the cell metabolism (intracellular Ca²⁺ concentration [Ca²⁺]_i and mitochondrial activity) and the cell function (endocrine activity) were assessed. It has been found that the exposure to the field did not affect the cell viability, but the doubling time was significantly reduced (p < 0.05) in exposed samples after 72 h of culture. At the same time, the cell length and thickness significantly changed (p < 0.05), while the cell orientation was unaffected. Evident modifications were induced on actin and α-tubulin cytoskeleton after 3 days of exposure and, simultaneously, a change in [Ca²⁺]_i and mitochondrial activity started to become evident. Finally, the SMF exposure of GCs longer than 72 h determined a significant alteration of progesterone and estrogen production (p < 0.05). In conclusion, our results demonstrate that the chronic exposure of swine GCs to a 2 mT SMF exerts a negative effect on cell proliferation, morphology, biochemistry and endocrine function in an in vitro model.     

Geomagnetic field modulates artificial static magnetic field effect on arterial baroreflex and on microcirculation

Spreading evidence suggests that geomagnetic field (GMF) modulates artificial magnetic fields biological effect and associated with increased cardiovascular morbidity. To explore the underlying physiological mechanism we studied 350 mT static magnetic field (SMF) effect on arterial baroreflex-mediated skin microcirculatory response in conjunction with actual geomagnetic activity, reflected by K and K _p indices. Fourteen experiments were performed in rabbits sedated by pentobarbital infusion (5 mg/kg/h). Mean femoral artery blood pressure, heart rate, and the ear lobe skin microcirculatory blood flow, measured by microphotoelectric plethysmogram (MPPG), were simultaneously recorded before and after 40 min of NdFeB magnets local exposure to sinocarotid baroreceptors. Arterial baroreflex sensitivity (BRS) was estimated from heart rate/blood pressure response to intravenous bolus injections of nitroprusside and phenylephrine. We found a significant positive correlation between SMF-induced increase in BRS and increment in microvascular blood flow (ΔBRS with ΔMPPG, r=0.7, p<0.009) indicated the participation of the arterial baroreflex in the regulation of the microcirculation and its enhancement after SMF exposure. Geomagnetic disturbance, as opposed to SMF, decreased both microcirculation and BRS, and counteracted SMF-induced increment in microcirculatory blood flow (K-index with ΔMPPG; r _s=−0.55, p<0.041). GMF probably affected central baroreflex pathways, diminishing SMF direct stimulatory effect on sinocarotid baroreceptors and on baroreflex-mediated vasodilatatory response. The results herein may thus point to arterial baroreflex as a possible physiological mechanism for magnetic-field cardiovascular effect. It seems that geomagnetic disturbance modifies artificial magnetic fields biological effect and should be taken into consideration in the assessment of the final effect. An erratum to this article can be found at     

Effect of 6 mT static magnetic field on the bcl-2, bax, p53 and hsp70 expression in freshly isolated and in vitro aged human lymphocytes

An increasing number of evidence indicates that static magnetic fields (SMFs) are capable of altering apoptosis, mainly through modulation of Ca²⁺ influx. Here we present data that suggest apoptotic-related gene expression as an alternative pathway, through which exposure to 6 milliTesla (mT) SMF can interfere with apoptosis. Exposure to 6 mT SMF affects the apoptotic rate (spontaneous and drug-induced) and [Ca²⁺]_i in isolated human lymphocytes; the aged cells are more susceptible to exposure than fresh ones. The exposure to 6 mT exerted a protective effect on chemical or physical-induced apoptosis, irrespective of the age of the cells.The investigation of the gene expression of bcl-2, bax, p53 and hsp70 in freshly isolated and in culture-aged human lymphocytes indicates that these genes are modulated by SMF exposure in the experimental conditions used, in a gene-, age- and time-dependent manner. The exposure of isolated lymphocytes to SMF for up to 24 h modulated increased bax and p53 and decreased hsp70, and bcl-2. The amount of increment and/or decrement of the proteins varied for each gene examined and was independent of the apoptotic inducers. Finally, the same stress applied to freshly isolated or aged lymphocytes resulted in different modulation of bcl-2, bax and hsp70.     

Changes in Saccharomyces cerevisiae development induced by magnetic fields

Saccharomyces cerevisiae cultures exposed to 110 mT and 220 mT steady magnetic fields (SMF) were studied to observe eventual induced growth alterations and changes in metabolic activity. Cell mass (biomass) growth was evaluated by light spectrometry, and metabolic alterations were estimated on the basis of the CO2 pressure produced and by the culture media pH changes, measured at the beginning and the end of the observation. The yeast strain DAUFPE-1012, cultivated in a nonaerated liquid agar Sabouraud glucose medium, was exposed to SMF generated by NdFeBr magnets. Results showed alterations induced by 220 mT SMF as an increment in cell proliferation (1.84%) and an increased CO2 production (36.1%) as compared to control groups. Furthermore, the initial-to-final pH difference in 220 mT SMF exposed cultures was higher than the 110 mT SMF and the control values. The whole acidification and the rise in CO2 production observed after 220 mT SMF exposure did not correspond to the biomass growth values, as compared to the other cultures, and was apparently provoked by a enhancement in the cellular metabolic rate. This technique becomes very promising for future biotechnological applications in fermentative processes.     

Static magnetic field effect on microcirculation,direct versus baroreflex-mediated approach

We compared in conscious rabbits, sedated using pentobarbital intravenous (i.v.) infusion (5 mg kg^{? 1} h^{? 1}), the effect of a static magnetic field (SMF), generated by Nd₂–Fe₁₄–B magnets, on microcirculation during its 40 min local exposure to the microvascular network in cutaneous tissue [20 sham exposure and 20 SMF (0.25 T) exposure runs] or to sinocarotid baroreceptors [14 sham exposure and 14 SMF (0.35 T) exposure runs]. Mean femoral artery blood pressure (BP), heart rate (HR), arterial baroreflex sensitivity (BRS), assessed from HR and BP responses to i.v. bolus of nitroprusside and phenylephrine, and microcirculatory blood flow, using microphotoelectric plethysmography (MPPG), were simultaneously monitored. SMF significantly increased microcirculation on a 17.8% in microvascular and on a 23.3% in baroreceptor exposure series. In baroreceptor exposure series, SMF significantly decreased BP, increased heart rate variability, BRS and sodium nitroprusside (NO-donor) i.v. bolus microcirculatory vasodilatory effect. These suggest augmentation of the arterial baroreflex capacity support NO-dependent vasodilation, by increased sensitivity of vessels to NO, to be a new physiological mechanism of BP buffering and microcirculatory control. A significant positive correlation was also found between increase in BRS and in MPPG (r = 0.66, p < 0.009), indicating baroreflex participation in the regulation of the microcirculation and its enhancement after SMF exposure. Both direct and baroreflex-mediated approaches demonstrate SMF significant vasodilatory effect with potential clinical implication in macro- and microcirculatory disorders.     

Combined effect of X‐ray radiation and static magnetic fields on reactive oxygen species in rat lymphocytes in vitro

The aim of this study was to investigate the effect of static magnetic fields (SMF) on reactive oxygen species induced by X‐ray radiation. The experiments were performed on lymphocytes from male albino Wistar rats. After exposure to 3 Gy X‐ray radiation (with a dose rate of 560 mGy/min) the measurement of intracellular reactive oxygen species in lymphocytes, using a fluorescent probe, was done before exposure to the SMF, and after 15 min, 1 and 2 h of exposure to the SMF or a corresponding incubation time. For SMF exposure, 0 mT (50 µT magnetic field induction opposite to the geomagnetic field) and 5 mT fields were chosen. The trend of SMF effects for 0 mT was always opposite that of 5 mT. The first one decreased the rate of fluorescence change, while the latter one increased it. Bioelectromagnetics 34:333–336, 2013. © 2012 Wiley Periodicals, Inc.     

EVIDENCE OF SYNCHRONIZATION OF NEURONAL ACTIVITY OF MOLLUSCAN BRAIN GANGLIA INDUCED BY ALTERNATING 50 Hz APPLIED MAGNETIC FIELD

Experimental evidence for the appearance of synchronized bioelectric activity in neurons under applied extremely low frequency (ELF) magnetic fields is shown. We have studied the synchronizing process by recording the intracellular bioelectric activity from pairs of neurons randomly chosen from the brain ganglia of the snail Helix aspersa. The recordings were made in real time under exposure to sinusoidal low frequency (50 Hz) weak (B₀=1–15 mT) magnetic fields. Synchronization was observed in 27% of the pairs tested. A linear dependence of the firing frequency f with the energy density of the applied magnetic field (i.e., f∝B₀²) was presented. The ability of low frequency sinusoidal weak magnetic fields to promote “magnetic synchronization” is exciting and opens new avenues for induced electromagnetic field bioeffects.     

Morphofunctional study of 12‐O‐tetradecanoyl‐13‐phorbol acetate (TPA)‐induced differentiation of U937 cells under exposure to a 6 mT static magnetic field

This study deals with the morphofunctional influence of 72 h exposure to a 6 mT static magnetic field (SMF) during differentiation induced by 50 ng/ml 12‐O‐tetradecanoyl‐13‐phorbol acetate (TPA) in human leukaemia U937 cells. The cell morphology of U937 cells was investigated by optic and electron microscopy. Specific antibodies and/or molecules were used to label CD11c, CD14, phosphatidylserine, F‐actin and to investigate the distribution and activity of lysosomes, mitochondria and SER. [Ca²⁺]_i was evaluated with a spectrophotometer. The degree of differentiation in SMF‐exposed cells was lower than that of non‐exposed cells, the difference being exposure time‐dependent. SMF‐exposed cells showed cell shape and F‐actin modification, inhibition of cell attachment, appearance of membrane roughness and large blebs and impaired expression of specific macrophagic markers on the cell surface. The intracellular localization of SER and lysosomes was only partially affected by exposure. A significant localization of mitochondria with an intact membrane potential at the cell periphery in non‐exposed, TPA‐stimulated cells was observed; conversely, in the presence of SMF, mitochondria were mainly localised near the nucleus. In no case did SMF exposure affect cell viability. The sharp intracellular increase of [Ca²⁺]_i could be one of the causes of the above‐described changes. Bioelectromagnetics 30:352–364, 2009. © 2009 Wiley‐Liss, Inc.     

Exposure to a moderate intensity static magnetic field enhances the hypotensive effect of a calcium channel blocker in spontaneously hypertensive rats

We investigated the combined effects of a moderate intensity static magnetic field (SMF) and an L-type voltage-gated Ca(2+) channel blocker, nicardipine in stroke-resistant spontaneously hypertensive rats during the development of hypertension. Five-week-old male rats were exposed to SMF intensity up to 180 mT (B(max)) with a peak spatial gradient of 133 mT/mm for 14 weeks. Four experimental groups of 14 animals each were examined: (1) sham exposure with intraperitoneal (ip) saline injection (control); (2) SMF exposure with ip saline injection (SMF); (3) sham exposure with ip nicardipine injection (NIC); (4) SMF exposure with ip nicardipine injection (SMF + NIC). A disc-shaped permanent magnet or a dummy magnet was implanted in the vicinity adjacent to the left carotid sinus baroreceptor region in the neck of each rat. Nicardipine (2 mg/kg ip) was administered three times a week for 14 weeks, and then 15 min after each injection, arterial blood pressure (BP), heart rate (HR), baroreflex sensitivity (BRS), skin blood flow (SBF), skin blood velocity (SBV), plasma nitric oxide (NO) metabolites (NO(x) = NO(2) (-) + NO(3) (-)), plasma catecholamine levels and behavioral parameters of a functional observational battery were monitored. The action of nicardipine significantly decreased BP, and increased HR, SBF, SBV, plasma epinephrine and norepinephrine in the NIC group compared with the control respective age-matched group without changing plasma NO(x) levels. Neck exposure to SMF alone for 5-8 weeks significantly suppressed or retarded the development of hypertension together with increased BRS in SMF group. Furthermore, the exposure to SMF for 1-8 weeks significantly promoted the nicardipine-induced BP decrease in the SMF + NIC group compared with the respective NIC group. Moreover, the SMF induced a significant increase in plasma NO(x) in the nicardipine-induced hypotension. There were no significant differences in any of the physiological or behavioral parameters measured between the SMF + NIC and the NIC groups, nor between the SMF and the control groups. These results suggest that the SMF may enhance nicardipine-induced hypotension by more effectively antagonizing the Ca(2+) influx through the Ca(2+) channels compared with the NIC treatment alone. Furthermore, the enhanced antihypertensive effects of the SMF on the nicardipine-treated group appear to be partially related to the increased NO(x). Theoretical considerations suggest that the applied SMF (B(max) 40 mT, 0 Hz) can be converted into a changing magnetic field (B(max) 30-40 mT, 5.7-6.5 Hz or 7.5-8.3 Hz) in the baroreceptor region by means of the carotid artery pulsation. Therefore, we propose that the moderate intensity changing magnetic field, i.e., the magnetic field modulated by the pulse rate, may influence the activity of baroreceptor and baroreflex function.     

Seed orientation and magnetic field strength have more influence on tomato seed performance than relative humidity and duration of exposure to non-uniform static magnetic fields

Different factors (e.g., light, humidity, and temperature) including exposure to static magnetic fields (SMFs), referred here as critical factors, can significantly affect horticultural seed performance. However, the link between magnetic field parameters and other interdependent factors affecting seed viability is unclear. The importance of these critical factors affecting tomato (Solanum lycopersicum L.) var. MST/32 seed performance was assessed after performing several treatments based on a L₉ (3⁴) (four factors at three levels) orthogonal array (OA) design. The variable factors in the design were magnetic flux density (R₁ = 332.1 ± 37.8 mT; R₂ = 108.7 ± 26.9 mT; and R₃ = 50.6 ± 10.5 mT), exposure time (1, 2, and 24 h), seed orientation (North polarity, South polarity, and control – no magnetic field), and relative humidity (RH) (7.0, 25.5, and 75.5%). After seed moisture content stabilisation at the different chosen RH, seeds were exposed in dark under laboratory conditions to several treatments based on the OA design before performance evaluation. Treatments not employing magnetic field exposure were used as controls. Results indicate that electrolyte leakage rate was reduced by a factor of 1.62 times during seed imbibition when non-uniform SMFs were employed. Higher germination (∼11.0%) was observed in magnetically-exposed seeds than in non-exposed ones, although seedlings emerging from SMF treatments did not show a consistent increase in biomass accumulation. The respective influence of the four critical factors tested on seed performance was ranked (in decreasing order) as seed orientation to external magnetic fields, magnetic field strength, RH, and exposure time. This study suggests a significant effect of non-uniform SMFs on seed performance with respect to RH, and more pronounced effects are observed during seed imbibition rather than during later developmental stages.     

The Influence of a gradient static magnetic field on an unstirred Belousov-Zhabotinsky reaction

It is believed that static magnetic fields (SMF) cannot affect the pattern formation of the Belousov-Zhabotinsky (BZ) reaction, which has been frequently studied as a simplified experimental model of a nonequilibrium open system, because SMF produces no induced current and the magnetic force of SMF far below 1 T is too low to expect the effects on electrons in the BZ reaction. In the present study, we examined whether the velocity of chemical waves in the unstirred BZ reaction can be affected by a moderate-intensity SMF exposure depending on the spatial magnetic gradient. The SMF was generated by a parallel pair of attracting rectangular NdFeB magnets positioned opposite each other. The respective maximum values of magnetic flux density (B(max)), magnetic flux gradient (G(max)), and the magnetic force product of the magnetic flux density its gradient (a magnetic force parameter) were 206 mT, 37 mT/mm, and 3,000 mT(2)/mm. The ferroin-catalyzed BZ medium was exposed to the SMF for up to 16 min at 25 degrees C. The experiments demonstrated that the wave velocity was significantly accelerated primarily by the magnetic gradient. The propagation of the fastest wave front indicated a sigmoid increase along the peak magnetic gradient line, but not along the peak magnetic force product line. The underlying mechanisms of the SMF effects on the anomalous wave propagation could be attributed primarily to the increased concentration gradient of the paramagnetic iron ion complexes at the chemical wave fronts induced by the magnetic gradient.     

Spatial gradient effects of 120 mT static magnetic field on endothelial tubular formation in vitro

This study investigated the spatial magnetic gradient effects of static magnetic fields (SMF) on endothelial tubular formation by applying the maximum spatial gradient to a target site of culture wells for cell growth. The respective maximum values of magnetic flux density (B(max)), magnetic flux gradient (G(max)) and the magnetic force product of the magnetic flux density and its gradient (a parameter of magnetic force) were 120 mT, 28 mT/mm and 1428 mT(2)/mm. The effects of gradient SMF on tubular formation were compared with those of uniform SMF that has no spatial gradients on the entire bottom area of culture wells. Five experimental groups of 25 samples each were examined: (1) sham exposure (control); (2) peak gradient exposure in the peripheral part; (3) peak gradient exposure in the central part; (4) uniform exposure to 20 mT; (5) uniform exposure to 120 mT. The SMF or sham exposure was carried out for 10 days. Photomicrographs of tubular cells, immunostained with an anti-platelet-endothelial cell adhesion molecule-1 (PECAM-1 [CD31]) antibody as a pan-endothelial marker, were analyzed after the 10-day culture. Gradient SMF in the peripheral or central part was found to significantly promote tubular formation in terms of the area density and length of tubules in each peak gradient/force part of the wells, compared with the sham exposure. In contrast, uniform SMF did not induce any significant change in the tubular formation. These findings suggest that tubule formation can be promoted by applying the peak gradient/force to a target site of culture wells.     

SNAIL NEURON BIOELECTRIC ACTIVITY INDUCED UNDER STATIC OR SINUSOIDAL MAGNETIC FIELDS REPRODUCES MAMMAL NEURON RESPONSES UNDER TRANSCRANIAL MAGNETIC STIMULATION

We have applied static (SMF) or alternating magnetic fields (AMF) to snail (Helix aspersa) single-unit neurons, in the range of those applied in magnetic stimulation (MS)/transcranial magnetic stimulation (TMS). From the experiments we have performed during the past 10 years, we have collected a blind selection of neurons and their responses to either SMF or AMF. Blind selection means that we do not know the nature of neurons. We do not know whether they are sensitive, motor, secretory, pacemaker, or inter-neurons. We have seen that the behavior of single-unit neurons under SMF/AMF exposure (SMF range: 3 mT–0.7 T; AMF range: 1–15 mT) fits well with the electrophysiologic activity described for mammals and human whole brain under MS/TMS (pulsed magnetic field range: 0.3 mT–2.4 T). The neuron experiments shown here have been aleatorily selected from a collection of about 200 neurons studied. Our results could explain some of the effects described induced in mammal neurons under MS/TMS for clinical purposes.     

Impact of Inhomogeneous Static Magnetic Field (31.7–232.0 mT) Exposure on Human Neuroblastoma SH-SY5Y Cells during Cisplatin Administration

Beneficial or adverse effects of Static Magnetic Fields (SMFs) are a large concern for the scientific community. In particular, the effect of SMF exposure during anticancer therapies still needs to be fully elucidated. Here, we evaluate the effects of SMF at induction levels that cisPt-treated cancer patients experience during the imaging process conducted in Low field (200–500 mT), Open field (300–700 mT) and/or inhomogeneous High field (1.5–3 T) Magnetic Resonance Imaging (MRI) machines. Human adrenergic neuroblastoma SH-SY5Y cells treated with 0.1 µM cisPt (i.e. the lowest concentration capable of inducing apoptosis) were exposed to SMF and their response was studied in vitro. Exposure of 0.1 µM cisPt-treated cells to SMF for 2 h decreased cell viability (30%) and caused overexpression of the apoptosis-related cleaved caspase-3 protein (46%). Furthermore, increase in ROS (Reactive Oxygen Species) production (23%) and reduction in the number of mitochondria vs controls were seen. The sole exposure of SMF for up to 24 h had no effect on cell viability but increased ROS production and modified cellular shape. On the other hand, the toxicity of cisPt was significantly prevented during 24 h exposure to SMF as shown by the levels of cell viability, cleaved caspase-3 and ROS production. In conclusion, due to the cytoprotective effect of 31.7–232.0 mT SMF on low-cisPt-concentration-treated SH-SY5Y cells, our data suggest that exposure to various sources of SMF in cancer patients under a cisPt regimen should be strictly controlled.