The effect of oscillating low intensity magnetic field on the Na+, K+, Ca++, and Mg++ concentrations in the maternal and fetal circulation of the dually perfused human placental cotyledon

Endogenous Ca2+ release was involved in 50-Hz MF-induced proliferation via Akt-SK1 signal cascade in human amniotic epithelial cells

The mechanism underlying the biological effects caused by an extremely low-frequency electromagnetic field (ELF-EMF) is still unclear. Previously, we found that L-type calcium channel and sphingosine kinase 1 (SK1) were involved in 50-Hz MF exposure-induced cell proliferation. In the present study, the role of intracellular Ca²⁺ and signal molecules related to SK1 in cell proliferation induced by 50-Hz MF was investigated in human amniotic epithelial (FL) cells. Results showed that the intracellular Ca²⁺ chelator, BAPTA, could completely inhibit 50-Hz MF-induced cell proliferation, whereas NIF, the inhibitor of L-type calcium channel, only partly blocked it. When cells were cultured in calcium-free medium, MF exposure also increased intracellular Ca²⁺, activated SK1 and promoted cell proliferation although all of those increasing levels were lower than those in complete medium. Moreover, MF-activated SK1 could be completely inhibited by BAPTA, and MF-induced cell proliferation was abolished by SKI II, the specific inhibitor of SK1. Additionally, a 50-Hz MF exposure did not affect the activation of ERK and PKCα under the condition of calcium-free medium, but activated the Akt, which could be precluded entirely by BAPTA, but not be inhibited by NIF. Treatment of FL cells with LY294002, the inhibitor of Akt, could delete the MF-induced SK1 activation under the condition of calcium-free medium. Based on the data from the present experiment, it is concluded that endogenous Ca²⁺ release was involved in 50-Hz MF-induced cell proliferation via Akt-SK1 signal cascade.

The efficacy and safety of low-frequency rotating static magnetic field therapy combined with chemotherapy on advanced lung cancer patients: a randomized, double-blinded, controlled clinical trial

Purpose: To evaluate the efficacy and safety of magnetic field (MF) therapy by a randomized, double-blinded, controlled clinical trial.Materials and methods: From February 2016 to August 2019, patients with advanced lung cancer who conformed to inclusion criteria were enrolled in this study. Patients were assigned into MF therapy group (MF group, receiving both MF therapy and chemotherapy) and control group (CON group, receiving sham MF therapy and chemotherapy) randomly. The treatment course was 21 days and 2 hours per day. Changes of life quality assessment scales, objective response rate (ORR) and disease control rate (DCR) were analyzed as primary end points. The secondary end points were progression-free survival (PFS), change of blood cytokine concentrations and safety. This study has been registered on Clinicaltrials.gov (ID: NCT02701231).Results: 77 patients were enrolled and 60 finished the study. Comparing to CON group, more patients in MF group (66.7% vs 25.9%) were experiencing life quality improvement on day 21. Besides, MF group patients had higher concentrations of IP-10 and GM-CSF, and lower concentration of sTREM-1 in plasma. However, the two groups were having similar ORR, DCR and PFS after treatment. Moreover, MF treatment did not increase adverse events in MF group.Conclusions: MF therapy could improve life quality and modulate blood cytokine concentration in advanced lung cancer patients. Hence, it might be applied as an adjuvant therapy along with chemotherapy.

Reactive oxygen species mediates 50-Hz magnetic field-induced EGF receptor clustering via acid sphingomyelinase activation

PURPOSE

Exposure to extremely low frequency electromagnetic fields (ELF-EMFs) could elicit biological effects including carcinogenesis. However, the detailed mechanisms by which these ELF-EMFs interact with biological system are currently unclear. Previously, we found that a 50-Hz magnetic field (MF) exposure could induce epidermal growth factor receptor (EGFR) clustering and phosphorylation on cell membranes. In the present experiment, the possible roles of reactive oxygen species (ROS) in MF-induced EGFR clustering were investigated.

MATERIALS AND METHODS

Human amnion epithelial (FL) cells were exposed to a 50-Hz MF with or without N-acetyl-l-cysteine (NAC) or pyrrolidine dithiocarbamate (PDTC). EGFR clustering on cellular membrane surface was analyzed using confocal microscopy after indirect immunofluorescence staining. The intracellular ROS level and acid sphingomyelinase (ASMase) activity were detected using an ROS assay kit and an Amplex^® Red Sphingomyelinase Assay Kit, respectively.

RESULTS

Results showed that exposure of FL cells to a 50-Hz MF at 0.4 mT for 15 min significantly enhanced the ROS level, induced EGFR clustering and increased ASMase activity. However, pretreatment with NAC or PDTC, the scavenger of ROS, not only counteracted the effects of a 50-Hz MF on ROS level and AMS activity, but also inhibited the EGFR clustering induced by MF exposure.

CONCLUSIONS

The present and previous data suggest that ROS mediates the MF-induced EGFR clustering via ASMase activation.

Effect of electromagnetic fields and antioxidants on the trace element content of rat teeth

The purpose of this study was to examine the possible effect of extremely low-frequency electromagnetic fields (ELF-EMFs), from a high-voltage source, on rat teeth in terms of changes in trace elements (TEs) and the effect of antioxidants (melatonin [MLT] and Ganoderma lucidum [GL]) in counteracting these effects. We used adult male Wistar albino rats with a mean weight of 250–300 g and divided the rats into eight groups. The groups were subjected to an ELF-EMF that was applied with a high-voltage line for 8 hours/day for 26 days (Groups I, II, and III) or 52 days (Groups V, VI, and VII). Groups IV and VIII were the 26- and 52-day control/sham groups, respectively. Groups II and VI were treated with GL, and Groups III and VII were treated with MLT. MLT and GL were administered daily based on the weight of the animals and appropriate standards. At the end of the study, the rats were euthanized, and their anterior teeth were extracted. The teeth were preserved in pure water before evaluating the major TEs. At the end of the study, TE concentrations (in mg/kg) were assessed in the control and test groups. Compared with Group V, statistically significant differences in the concentrations of zinc (Zn) and strontium (Sr) were found for Group VII (ELF-EMF + MLT) (P<0.05). Therefore, ELF-EMF exposure can change the content of certain TEs in teeth and, after administering MLT and GL, the values of some of the TEs return to normal.

Extremely low-frequency magnetic field decreased calcium, zinc and magnesium levels in costa of rat

Electromagnetic field (EMF) can affect cells due to biochemical change followed by a change in level of ions trafficking through membrane. We aimed to investigate possible changes in some elements in costa of rats exposed to long-term extremely low-frequency magnetic field (ELF-MF). Rats were exposed to 100 and 500 μT ELF-MF, which are the safety standards of public and occupational exposure for 2 h/day during 10 months. At the end of the exposure period, the samples of costa were taken from the rats exposed to ELF-MF and sham. The levels of elements were measured by using atomic absorption spectrophotometry (AAS) and ultraviolet (UV) spectrophotometry. Ca levels decreased in the ELF-500 exposure group in comparison to sham group (p < 0.05). Statistically significant decrease was found in Mg levels in the ELF-500 exposure group in comparison to sham and ELF-100 exposure groups (p < 0.05). Zn levels were found to be lower in the ELF-500 exposure group than those in the sham and ELF-100 exposure groups (p < 0.05). No significant differences were determined between groups in terms of the levels of P, Cu and Fe. In conclusion, it can be maintained that long-term ELF-MF exposure can affect the chemical structure and metabolism of bone by changing the levels of some important elements such as Ca, Zn and Mg in rats.

Molecular mapping deep within a living human organ: analysis of microvessel function on the timescale of seconds and with sub-micrometre spatial resolution

Visualising vascular endothelial cell function in individual blood microvessels allows elucidation of molecular interactions at the vascular wall, the first barrier between blood-borne therapeutic agent and its target. Functional analysis in situ requires sub-micrometer spatial resolution and tagged molecules generating contrast in living blood vessels. Light microscopy fulfills these requirements, particularly if fluorescent tags deliver the contrast. However, vascular arborisations in living organs defy morpho-functional analysis, filling tissues with closely meshed three-dimensional networks which are inaccessible to optical imaging. We protocol here successful morpho-functional analysis of microvascular processing in a living organ, the human placental cotyledon. Fluorescence-tagged tracer was positionally fixed by snap-freezing, frozen sections were cut, freeze-dried and heat-fixed. A brief histochemical procedure then labelled all vascular elements in the sections, providing fluorescence contrast in two colour channels. Mosaic monochromatic images acquired in both channels delivered high-resolution maps of centimeter-wide tissue areas. Quantitative analysis of the images' greyscale histograms defined objectifiable, reproducible thresholds, used to reduce the images to colour-coded wide-area functional maps tracking placental vascular processing of the tagged molecules. Rapid positional fixing of tracer with reduction of images to maps was combined with ultrastructural tracking to elucidate vascular processing at scales of nanometres and seconds.

Low dose magnetic fields do not cause oxidative DNA damage in human placental cotyledons in vitro

The biological impact of low dose magnetic fields generated by electric appliances present in the human environment is still uncertain. In this study, human placentas served as a model tissue for the evaluation of the potential effect of oscillating low intensity magnetic fields on the concentration of 8-hydroxy-2'-deoxyguanosine (8-OH-dG) in cellular DNA. Cotyledons were dissected from placentas obtained immediately after physiological labours and exposed to magnetic fields (groups MF A, 2 mT, 50 Hz and MF B, 5 mT, 50 Hz) or sham exposed (group C) during an in vitro perfusion of 3 h. Cellular DNA was isolated, hydrolyzed and analyzed by HPLC. Native nucleosides were monitored at 254 nm and 8-OH-dG by electrochemical detection. Results were expressed as mumol 8-OH-dG/mol deoxyguanosine (dG). The concentrations of 8-OH-dG in group C, MF A and MF B were 28.45+/-15.27 micromol/mol dG, 62.80+/-31.91 mumol/mol dG, and 27.49+/-14.23 micromol/mol dG, respectively, demonstrating no significant difference between the groups. The results suggest that placental tissues possess a capacity to protect DNA against oxidative alterations by magnetic field of intensities previously shown to produce radical mediated DNA damage in rat brain cells in vivo and imbalances in electrolyte release of cotyledons under in vitro conditions.