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Capri, M., Mesirca, P., Remondini, D., Carosella, S., Pasi, S., Castellani, G., et al. (2004). 50 Hz sinusoidal magnetic fields do not affect human lymphocyte activation and proliferation in vitro. Phys Biol, 1(3-4), 211–219.
Abstract: In the last 30 years, an increasing public concern about the possible harmful effects of electromagnetic fields generated by power lines and domestic appliances has pushed the scientific community to search for a correct and comprehensive answer to this problem. In this work the effects of exposure to 50 Hz sinusoidal magnetic fields, with a magnetic flux density of 0.05 mT and 2.5 mT (peak values), were studied on human peripheral blood mononuclear cells (PBMCs) collected from healthy young and elderly donors. Cell activation and proliferation were investigated by using flow cytometry techniques and 3H-TdR incorporation assays, respectively. The results obtained indicated that exposure to the fields altered neither DNA synthesis nor the capacity of lymphocytes to enter the activation phase and progress into the cell cycle. Thus, the conclusions are that two important functional phases of human lymphocytes, such as activation and proliferation, are not affected by exposures to 50 Hz magnetic fields similar to those found under power lines.
Keywords: Adult; Aged; Cell Cycle; Cell Proliferation/*radiation effects; Flow Cytometry; Humans; Lymphocyte Activation/*radiation effects; *Magnetics; Phenotype
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Tsukasa Shigemitsu, K. T., Yoichi Shiga, and Masamichi Kato. (1993). 50-Hz Magnetic Field Exposure System for Small Animals. Bioelectromagnetics, 14, 107–116.
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Ke, X. Q., Sun, W. J., Lu, D. Q., Fu, Y. T., & Chiang, H. (2008). 50-Hz magnetic field induces EGF-receptor clustering and activates RAS. Int J Radiat Biol, 84(5), 413–420.
Abstract: PURPOSE: In a previous study, we found that exposure to a 50 Hz magnetic field (MF) could activate stress-activated protein kinase (SAPK) and P38 mitogen-activated protein (MAP) kinase (P38 MAPK) in Chinese hamster lung (CHL) fibroblast cells, and simultaneous exposure to a 'noise' MF of the same intensity inhibited these effects. In order to explore the possible target sites and upstream signal transduction molecules of SAPK and P38 MAPK, and further validate the interference effects of 'noise' MF on 50 Hz MF, the effects of MF exposure on clustering of epidermal growth factor (EGF) receptors and Ras protein activation were investigated. MATERIALS AND METHODS: CHL cells were exposed to a 50 Hz sinusoidal MF at 0.4 mT for different durations, and clustering of EGF receptors on cellular membrane and Ras protein activation were analyzed using immunofluorescence confocal microscopy and co-precipitation technology. EGF treatment served as the positive control. RESULTS: The results showed that, compared with sham-exposed cells, exposure to a 50 Hz MF at 0.4 mT for 5 min slightly induced EGF receptor clustering, whereas exposure for 15 min enhanced receptor clustering significantly. Corresponding to receptor clustering, Ras protein was also activated after exposure to the 50 Hz MF. Exposure to a 'noise' MF (with frequency ranges from 30 – 90 Hz) at the same intensity and durations, did not significantly affect EGF receptor clustering and Ras protein. However, by superimposing the 'noise' MF, receptor clustering and Ras activation induced by 50 Hz MF were inhibited. CONCLUSION: The results suggested that membrane receptors could be one of the most important targets where extremely low frequency (ELF) MF interacts with cells, and Ras may participate in the signal transduction process of 50 Hz MF. Furthermore, a 'noise' MF could inhibit these effects caused by ELF-MF.
Keywords: Animals; Cell Membrane/metabolism; Cluster Analysis; Cricetinae; *Electromagnetic Fields; Fibroblasts/metabolism; *Genes, ras; Glutathione Transferase/metabolism; Immunoprecipitation; Microscopy, Confocal; Microscopy, Fluorescence; Receptor, Epidermal Growth Factor/*chemistry/metabolism; Signal Transduction/radiation effects; p38 Mitogen-Activated Protein Kinases/metabolism; ras Proteins/*metabolism
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Santini, M. T., Rainaldi, G., Ferrante, A., Indovina, P., Donelli, G., & Indovina, P. L. (2006). A 50 Hz sinusoidal magnetic field does not damage MG-63 three-dimensional tumor spheroids but induces changes in their invasive properties. Bioelectromagnetics, 27(2), 132–141.
Abstract: The possibility that a sinusoidal 50 Hz magnetic field with a magnetic flux density of 1 mT can damage MG-63 osteosarcoma spheroids and induce variations in the invasive properties of these three-dimensional model systems after 2 days of exposure was investigated. Specifically, possible damage induced by these fields was examined by determining changes in spheroid surface morphology (light microscopy), growth (spheroid diameter and protein content determination), lactate dehydrogenase release, and reduced glutathione amount. Possible changes in the invasive properties were studied by invasion chambers. The results show no induction of cell damage by ELF fields while invasion chamber assays demonstrate a significant increase in the invasive potential of exposed spheroids. In order to determine if the fibronectin or hyaluronan receptors are involved, Western blot analysis was conducted on these two proteins. No significant variations were observed in either receptor in MG-63 multicellular tumor spheroids.
Keywords: Cell Line, Tumor/pathology/radiation effects; Cell Proliferation/radiation effects; Dose-Response Relationship, Radiation; Electricity/*adverse effects; Electromagnetic Fields/*adverse effects; Humans; Neoplasm Invasiveness; Neoplasm Proteins/*metabolism; Osteosarcoma/*pathology/*physiopathology; Radiation Dosage; Spheroids, Cellular/*pathology/*radiation effects
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McLean, J. R., Thansandote, A., McNamee, J. P., Tryphonas, L., Lecuyer, D., & Gajda, G. (2003). A 60 Hz magnetic field does not affect the incidence of squamous cell carcinomas in SENCAR mice. Bioelectromagnetics, 24(2), 75–81.
Abstract: Two groups of SENCAR mice were treated with a single dose of carcinogen and then, for 23 weeks, with a chemical tumor promoter to induce skin tumors. During this period, one group was coexposed to a 2 mT power frequency (60 Hz) magnetic field, while the other was exposed to sham conditions. Application of the tumor promoter ceased after 23 weeks, but the exposure to sham conditions or magnetic fields continued for an additional 29 weeks. No difference was found between the two groups of mice in terms of the incidence of total tumors (P =.297) or squamous cell carcinomas (SSC) (P =.501). In summary, there was no evidence to support the hypotheses that 60 Hz magnetic fields (MF) can influence the development of either papillomas or SSC under our defined experimental conditions. The overall results add to previous animal studies that find no association between exposure to 60 Hz MF and the incidence of benign or malignant tumors.
Keywords: 9,10-Dimethyl-1,2-benzanthracene; Animals; Back/radiation effects; Carcinogens; Carcinoma, Squamous Cell/chemically induced/*etiology/pathology; Cocarcinogenesis; Drug Tolerance/radiation effects; Electricity; Electromagnetic Fields/*adverse effects; Mice; Mice, Inbred SENCAR; Neoplasms, Radiation-Induced/*etiology/pathology; Radiation Tolerance/drug effects; Reference Values; Skin/drug effects/pathology/*radiation effects; Skin Neoplasms/chemically induced/*etiology/pathology; Tetradecanoylphorbol Acetate
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