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Saito, A., Takayama, Y., Moriguchi, H., Kotani, K., & Jimbo, Y. (2009). Developmental effects of low frequency magnetic fields on P19-derived neuronal cells. Conf Proc IEEE Eng Med Biol Soc, 2009, 5942–5945.
Abstract: Modulation of pluripotent stem cell differentiation by several environmental factors, such as physical stimulation, is important theme in tissue engineering. In this study, we report the effects of extremely low frequency magnetic fields (ELF-MFs) exposure (1 mT or 10 mT, 50 Hz, sinusoidal) on the neuronal differentiation process of P19 embryonal carcinoma cells (P19 cells). Here, during induction of differentiation, the ELF-MFs exposed to embryoid bodies (EBs). After neuronal differentiation, the effects of ELF-MFs were evaluated by morphological analysis, immunochemical analysis (MAP2, GFAP), and the developmental neuronal network activities recorded by the micro-electrode arrays (MEAs). As a result, the percentage of MAP2 positive cells and the spike frequencies were increased by 10 mT ELF-MF, and then the percentage of GFAP positive cells were reduced. However, these effects were not seen in 1 mT exposed cells. Therefore, these results suggested that the intensity of a magnetic field was important for affecting a characteristic of neuronal differentiation and a functional neuronal network property.
Keywords: Cell Differentiation/*radiation effects; Cell Line; Dose-Response Relationship, Radiation; Electromagnetic Fields; Humans; Nerve Net/*cytology/*physiology/radiation effects; Neurons/*cytology/*physiology/radiation effects; Radiation Dosage
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Marley, R., Giachello, C. N. G., Scrutton, N. S., Baines, R. A., & Jones, A. R. (2014). Cryptochrome-dependent magnetic field effect on seizure response in Drosophila larvae. Sci Rep, 4, 5799.
Abstract: The mechanisms that facilitate animal magnetoreception have both fascinated and confounded scientists for decades, and its precise biophysical origin remains unclear. Among the proposed primary magnetic sensors is the flavoprotein, cryptochrome, which is thought to provide geomagnetic information via a quantum effect in a light-initiated radical pair reaction. Despite recent advances in the radical pair model of magnetoreception from theoretical, molecular and animal behaviour studies, very little is known of a possible signal transduction mechanism. We report a substantial effect of magnetic field exposure on seizure response in Drosophila larvae. The effect is dependent on cryptochrome, the presence and wavelength of light and is blocked by prior ingestion of typical antiepileptic drugs. These data are consistent with a magnetically-sensitive, photochemical radical pair reaction in cryptochrome that alters levels of neuronal excitation, and represent a vital step forward in our understanding of the signal transduction mechanism involved in animal magnetoreception.
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Chen, C., Ma, Q., Liu, C., Deng, P., Zhu, G., Zhang, L., et al. (2014). Exposure to 1800 MHz radiofrequency radiation impairs neurite outgrowth of embryonic neural stem cells. Scientific reports, 4(30), 5103.
Abstract: A radiofrequency electromagnetic field (RF-EMF) of 1800 MHz is widely used in mobile communications. However, the effects of RF-EMFs on cell biology are unclear. Embryonic neural stem cells (eNSCs) play a critical role in brain development. Thus, detecting the effects of RF-EMF on eNSCs is important for exploring the effects of RF-EMF on brain development. Here, we exposed eNSCs to 1800 MHz RF-EMF at specific absorption rate (SAR) values of 1, 2, and 4 W/kg for 1, 2, and 3 days. We found that 1800 MHz RF-EMF exposure did not influence eNSC apoptosis, proliferation, cell cycle or the mRNA expressions of related genes. RF-EMF exposure also did not alter the ratio of eNSC differentiated neurons and astrocytes. However, neurite outgrowth of eNSC differentiated neurons was inhibited after 4 W/kg RF-EMF exposure for 3 days. Additionally, the mRNA and protein expression of the proneural genes Ngn1 and NeuroD, which are crucial for neurite outgrowth, were decreased after RF-EMF exposure. The expression of their inhibitor Hes1 was upregulated by RF-EMF exposure. These results together suggested that 1800 MHz RF-EMF exposure impairs neurite outgrowth of eNSCs. More attention should be given to the potential adverse effects of RF-EMF exposure on brain development.
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Bakker, J. F., Paulides, M. M., Neufeld, E., Christ, A., Kuster, N., & van Rhoon, G. C. (2011). Children and adults exposed to electromagnetic fields at the ICNIRP reference levels: theoretical assessment of the induced peak temperature increase. Phys Med Biol, 56(15), 4967–4989.
Abstract: To avoid potentially adverse health effects of electromagnetic fields (EMF), the International Commission on Non-Ionizing Radiation Protection (ICNIRP) has defined EMF reference levels. Restrictions on induced whole-body-averaged specific absorption rate (SAR(wb)) are provided to keep the whole-body temperature increase (T(body, incr)) under 1 degrees C during 30 min. Additional restrictions on the peak 10 g spatial-averaged SAR (SAR(10g)) are provided to prevent excessive localized tissue heating. The objective of this study is to assess the localized peak temperature increase (T(incr, max)) in children upon exposure at the reference levels. Finite-difference time-domain modeling was used to calculate T(incr, max) in six children and two adults exposed to orthogonal plane-wave configurations. We performed a sensitivity study and Monte Carlo analysis to assess the uncertainty of the results. Considering the uncertainties in the model parameters, we found that a peak temperature increase as high as 1 degrees C can occur for worst-case scenarios at the ICNIRP reference levels. Since the guidelines are deduced from temperature increase, we used T(incr, max) as being a better metric to prevent excessive localized tissue heating instead of localized peak SAR. However, we note that the exposure time should also be considered in future guidelines. Hence, we advise defining limits on T(incr, max) for specified durations of exposure.
Keywords: Adult; Child; Child, Preschool; Electromagnetic Fields/*adverse effects; Environmental Exposure/*adverse effects/*standards; Female; Humans; Male; *Models, Anatomic; Monte Carlo Method; Radiation Dosage; Radiation Protection/*standards; Reference Standards; *Temperature; Uncertainty
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Mi, Y., Sun, C., Yao, C., Xiong, L., Wang, S., Li, C., et al. (2005). Lethal Effects of Steep Pulsed Electric Field (SPEF) to Target Lymphatic Capillaries in VX<inf>2</inf>Implanted Breast Cancer of Rabbits. Conf Proc IEEE Eng Med Biol Soc, 5, 4904–4907.
Abstract: This paper discussed the lethal effects of Steep Pulsed Electric Field (SPEF) to target lymphatic capillaries in VX<inf>2</inf>implanted breast cancer of rabbits using methylene blue dye injection staining, 5'-AMP-ALPase enzyme histochemical double staining, electron microscopy and VEGF-C observations. The result of methylene blue dye perfusion showed that the edge of tumor treated with SPEF was indistinct, no circularity or liner structure. Enzyme histochemical staining examination displayed that no positive staining was found in SPEF-target region of breast tumor, and lymphatic capillaries presented piecemeal structure in the edge of target region. Transmission electron microscopic examination showed that the continuity and integrality of lymphatic capillaries in tumor were destroyed after the treatment of SPEF. The expression of VEGF-C decreased markedly. The experiment indicated that SPEF induced the severe destruction of tumor cell and lymphatic capillaries in target region, and inhibited proliferation of lymphatic. Therefore it can decrease the possibility of lymphatic metastasis.
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