A cross-sectional study on oxidative stress in workers exposed to extremely low frequency electromagnetic fields

The Effect of Extremely Low-Frequency Magnetic Field on Stroke Patients: A Systematic Review

BACKGROUND

The aim of this study was to review the current state of scientific evidence on the effect of extremely low-frequency magnetic fields stimulation (ELF-MFs) on stroke patients.

METHODS

A systematic review of PubMed, ScienceDirect, PeDro and Embase databases was conducted. Only articles published in English, involving adult participants and focusing on individuals who had experienced a stroke, specifically examining the impact of ELF-MFs on post-stroke patients and had well-defined criteria for inclusion and exclusion of participants, were included. The methodological quality of the included studies was assessed using the Quality Assessment Tool for Quantitative Studies (QATQS).

RESULTS

A total of 71 studies were identified through database and reference lists' search, from which 9 were included in the final synthesis. All included studies showed a beneficial effect of ELF-MFs on stroke patients, however seven of the included studies were carried by the same research group. Improvements were observed in domains such as oxidative stress, inflammation, ischemic lesion size, functional status, depressive symptoms and cognitive abilities.

CONCLUSIONS

The available literature suggests a beneficial effect of ELF-MFs on post-stroke patients; however, the current data are too limited to broadly recommend the use of this method. Further research with improved methodological quality is necessary.

Conformational changes of β-thalassemia major hemoglobin and oxidative status of plasma after in vitro exposure to extremely low-frequency electromagnetic fields: An artificial neural network analysis

Electromagnetic fields (EMF) can generate reactive oxygen species and induce oxidative modifications. We investigated the effects of extremely low-frequency electromagnetic fields (ELF-EMF) on oxidative status of plasma and erythrocytes in β-thalassemia major patients and design artificial neural networks (ANN) for evaluating the oxyHb concentration. Blood samples were obtained from age and sex-matched healthy donors (n = 12) and major β-thalassemia patients (n = 12) and subjected to 0.5 and 1 mT and 50 Hz of EMF. Plasma oxidative status was estimated after 1 and 2 h exposure to ELE-EMF. Structural changes of plasma proteins were investigated by Native PAGE and SDS-PAGE. Moreover; multilayer perceptron (MLP) method was applied for designing a feed forward ANN model to predict the impact of these oxidative and antioxidative parameters on oxyHb concentration. Two hour exposure to ELF-EMF induced significant oxidative changes on major β-thalassemia samplesElectrophoretic profiles showed two high molecular weight (HMW) protein aggregates in plasma samples from healthy donors and major β-thalassemia patients. According to our ANN design, the main predictors of oxyHb concentration were optical density of Hb at 542, 340, 569, 630, 577, and 420 nm and metHb and hemichrome (HC) concentration. Accuracy of the proposed ANN model was shown by predicted by observed chart (y = 1.3 + 0.96x, R² = 0.942), sum of squares errors (SSR), and relative errors (RE). Our results showed the detailed effects of ELF-EMF on Hb structure and oxidative balance of plasma in major β-thalassemia patients and significance of ANN analysis during normal and pathologic conditions.

ESTIMATION OF THERMAL POWER PLANT WORKERS EXPOSURE TO MAGNETIC FIELDS AND SIMULATION OF HAZARD ZONES

Extremely low-frequency magnetic fields (ELF-MFs) have raised some concerns due to their possible effects on workers' health. In this study ELF-MFs were measured in different units of the thermal power plant based on gridding the indoor space. The exposure level was measured by spot measurement based on the IEEE Std C95.3.1 and then simulated in units with the highest magnetic field intensity by using ArcGIS software. The operators and balance of plant (BOP) technicians (12.64 ± 9.74 μT) and office workers (2.41 ± 1.22 μT) had the highest and lowest levels of both measured and estimated ELF-MFs exposure. The highest measured ELF-MFs were in the vicinity of the power transmission lines in the transformers' building (48.2 μT). Our simulation showed the high and low exposure areas and ranked exposure well; but, the actual measurements of ELF-MFs exposure were in all cases higher than the estimated values, which means we still need to improve our estimations.

Oxidative stress associated with long term occupational exposure to extremely low frequency electric and magnetic fields

BACKGROUND

Occupational exposure to extremely low frequency electromagnetic fields (ELF-EMFs) may have harmful effects on biologic systems and has raised many concerns in the last decades.

OBJECTIVE

The aim of this study was to determine the effects of exposure to extremely low frequency electric and magnetic fields on lipid peroxidation and antioxidant enzyme activities.

METHODS

This study was conducted on 115 power plant workers as the exposed group and 145 office workers as the non-exposed group. The levels of Malondialdehyde (MDA), superoxide dismutase (SOD), Catalase (Cat), and total antioxidant capacity (TAC) were measured in the serum of all subjects. Exposure to ELF-EMFs was measured based on spot measurements and the IEEE Std C95.3.1 standard.

RESULTS

The levels of MDA, SOD, and Cat in the exposed group were significantly higher than in the non-exposed group. However, the level of TAC was not significantly different between the exposed (2.45±1.02) and non-exposed (2.21±1.07) groups. The levels of MDA and SOD were higher among workers with higher exposure to electric fields than workers with low exposure. All oxidative stress indicators increased with increased exposure to magnetic fields, except TAC.

CONCLUSIONS

The antioxidant system imbalance among power plant workers may be related to long term occupational exposure to electromagnetic fields.

Role of Programmed Cell Death 4 (PDCD4)-Mediated Akt Signaling Pathway in Vascular Endothelial Cell Injury Caused by Lower-Extremity Ischemia-Reperfusion in Rats

BACKGROUND We aimed to investigate the role of PDCD4-mediated Akt signaling pathway in vascular endothelial cell injury caused by ischemia-reperfusion in the lower extremities. MATERIAL AND METHODS Ten rats were used as control, while 50 rats were used for creating disease models and were assigned to 5 groups: model group (no injection), NC group (injected with vectors containing PDCD negative control sequence), sh-PDCD4 group (injected with vectors containing sh-PDCD4 sequence), IGF-1 group (injected with IGF-1), and sh-PDCD4+IGF-1 group (injected with IGF-1 and vectors containing sh-PDCD4 sequence). RESULTS Compared with the control group, the expression levels of PDCD4 mRNA and protein, as well as levels of circulating endothelial cells, von Willebrand factor, thrombomodulin, and malondialdehyde, increased in the other 5 groups, while the mRNA and protein expression levels of Akt and eNOS, the protein expression levels of p-Akt and p-eNOS, and superoxide dismutase content decreased in these groups (all P<0.05). Compared with the model group, the sh-PDCD4 and sh-PDCD4+1GF-1 groups had lower mRNA and protein expressions of PDCD4 (all P<0.05), whereas the IGF-1 group had similar levels (all P>0.05). These 3 groups had lower levels of circulating endothelial cells, von Willebrand factor, thrombomodulin, and malondialdehyde, and higher mRNA and protein expressions of Akt and eNOS, protein expressions of p-Akt and p-eNOS, and superoxide dismutase content (all P<0.05). The NC group did not differ from the model group (all P>0.05). CONCLUSIONS PDCD4 gene silencing can activate the Akt signaling pathway and attenuate vascular endothelial cell injury caused by ischemia-reperfusion in the lower extremities in rats.