Abstract: Abstract Calcium transients play an essential role in cardiomyocytes and electromagnetic fields (EMF) and affect intracellular calcium levels in many types of cells. Effects of EMF on intracellular calcium transients in cardiomyocytes are not well studied. The aim of this study was to assess whether extremely low frequency electromagnetic fields (ELF-EMF) could affect intracellular calcium transients in cardiomyocytes. Cardiomyocytes isolated from neonatal Sprague-Dawley rats were exposed to rectangular-wave pulsed ELF-EMF at four different frequencies (15 Hz, 50 Hz, 75 Hz and 100 Hz) and at a flux density of 2 mT. Intracellular calcium concentration ([Ca(2+)]i) was measured using Fura-2/AM and spectrofluorometry. Perfusion of cardiomyocytes with a high concentration of caffeine (10 mM) was carried out to verify the function of the cardiac Na(+)/Ca(2+) exchanger (NCX) and the activity of sarco(endo)-plasmic reticulum Ca(2+)-ATPase (SERCA2a). The results showed that ELF-EMF enhanced the activities of NCX and SERCA2a, increased [Ca(2+)]i baseline level and frequency of calcium transients in cardiomyocytes and decreased the amplitude of calcium transients and calcium level in sarcoplasmic reticulum. These results indicated that ELF-EMF can regulate calcium-associated activities in cardiomyocytes.

Abstract: The effects of extremely low-frequency electric fields (ELF-EFs, 3-300Hz) on lipid peroxidation levels and antioxidant enzyme activities have been shown in many tissues and plasma after exposure to 50-Hz alternating current (AC) electric fields. However, similar studies investigating brain lipid peroxidation status are limited. Moreover and as far as we know, no study has been conducted to examine mismatch negativity (MMN) response in rats following exposure to a 50-Hz AC electric field. Therefore, the purpose of the study was to investigate different intensities and exposure durations of ELF-EFs on MMN component of event-related potentials (ERPs) as well as apoptosis and oxidative brain damage in rats. Ninety male rats, aged 3months were used in our study. A total of six groups, composed of 15 animals each, was formed as follows: sham-exposed rats for 2weeks (C2), sham-exposed rats for 4weeks (C4), rats exposed to 12-kV/m and 18-kV/m electric fields for 2weeks (E12-2 and E18-2), rats exposed to 12- and 18-kV/m electric fields for 4weeks (E12-4 and E18-4). At the end of the experimental period, MMN responses were recorded in urethane-anesthetized rats by electrodes positioned stereotaxically to the surface of the dura. After MMN recordings, animals were killed by exsanguination and their brain tissues were removed for 4-hydroxy-2-nonenal (4-HNE), protein carbonyl and TUNEL analysis. In the current study, different change patterns in ERP parameters were observed dependent on the intensity and exposure duration of ELF-EFs. There were differences in the amplitudes of ERP between the responses to the standard and the deviant tones in all groups. When peak-to-peak amplitude of the difference curves was evaluated, MMN amplitude was significantly decreased in the E18-4 group compared with the C4 group. Additionally, the amount of 4-HNE was increased in all experimental groups compared with the control group. Consequently, it could be concluded that electric field decreased MMN amplitudes possibly induced by lipid peroxidation.

Abstract: 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.