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Simko, M., Kriehuber, R., Weiss, D. G., & Luben, R. A. (1998). Effects of 50 Hz EMF exposure on micronucleus formation and apoptosis in transformed and nontransformed human cell lines. Bioelectromagnetics, 19(2), 85–91.
Abstract: Effects of applying extremely low-frequency electromagnetic fields (ELF-EMF) for different durations (24, 48, and 72 h) and different field intensities (0.1-1.0 mT) on micronucleus (MN) formation and induction of apoptosis were examined in a human squamous cell carcinoma cell line (SCL II) and in a human amniotic fluid cell line (AFC). A statistically significant increase of MN frequency and of induction of apoptosis in SCL II cells after 48-h and 72-h continuous exposure to 50 Hz magnetic field (MF) (0.8 and 1.0 mT) was found. However, exposure of AFC cells to EMF of different intensities and for different exposure times showed no statistically significant differences when compared with controls. These results demonstrate that different human cell types respond differently to EMF. Dose-dependent induction of apoptosis and genotoxic effects, resulting in increased micronucleus formation, could be demonstrated in the transformed cell line, whereas the nontransformed cell line did not show statistically significant effects. These findings suggest that EMF could be a promotor but not an initiator of carcinogenic effects.
Keywords: Amniotic Fluid/cytology/radiation effects; Apoptosis/*radiation effects; Carcinoma, Squamous Cell/pathology; Cell Line; Cell Line, Transformed; Humans; Micronuclei, Chromosome-Defective/pathology/*radiation effects; Micronucleus Tests; Tumor Cells, Cultured
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Antonopoulos, A., Eisenbrandt, H., & Obe, G. (1997). Effects of high-frequency electromagnetic fields on human lymphocytes in vitro. Mutat Res, 395(2-3), 209–214.
Abstract: Human peripheral lymphocytes were incubated in the presence of high-frequency electromagnetic fields of 380, 900 and 1800 MHz. The measured endpoints were cell cycle progression and the frequencies of sister-chromatid exchanges. No differences between treated and control cultures could be found.
Keywords: *Cell Cycle; Cells, Cultured; Electromagnetic Fields/*adverse effects; Humans; Lymphocytes/cytology/drug effects/*physiology; Phytohemagglutinins/pharmacology; *Sister Chromatid Exchange; Temperature
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Harland, J. D., & Liburdy, R. P. (1997). Environmental magnetic fields inhibit the antiproliferative action of tamoxifen and melatonin in a human breast cancer cell line. Bioelectromagnetics, 18(8), 555–562.
Abstract: We have previously reported that environmental-level magnetic fields (1.2 microT [12 milligauss], 60 Hz) block the growth inhibition of the hormone melatonin (10(-9) M) on MCF-7 human breast cancer cells in vitro. We now report that the same 1.2 microT, 60 Hz magnetic fields significantly block the growth inhibitory action of pharmacological levels of tamoxifen (10(-7) M). In biophysical studies we have taken advantage of Faraday's Law of Current Induction and tested whether the 1.2 microT magnetic field or the associated induced electric field is responsible for this field effect on melatonin and tamoxifen. We observe that the magnetic field component is associated with the field blocking effect on melatonin and tamoxifen function. To our knowledge the tamoxifen studies represent the first experimental evidence for an environmental-level magnetic field modification of drug interaction with human breast cancer cells. Together, these findings provide support to the theory that environmental-level magnetic fields can act to modify the action of a drug or hormone on regulation of cell proliferation. Melatonin and tamoxifen may act through different biological pathways to down-regulate cell growth, and further studies are required to identify a specific biological site of interaction for the 1.2 microT magnetic field.
Keywords: Antineoplastic Agents/*pharmacology; Breast Neoplasms/*drug therapy/*pathology; Cell Division/drug effects/radiation effects; Dose-Response Relationship, Radiation; *Electromagnetic Fields; *Environmental Exposure; Female; Growth Inhibitors/*pharmacology; Humans; Melatonin/*pharmacology; Tamoxifen/*pharmacology; Tumor Cells, Cultured
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Yasui, M., Kikuchi, T., Ogawa, M., Otaka, Y., Tsuchitani, M., & Iwata, H. (1997). Carcinogenicity test of 50 Hz sinusoidal magnetic fields in rats. Bioelectromagnetics, 18(8), 531–540.
Abstract: Male and female F344 rats, 48 per exposure group, were sham exposed (Group A) or exposed to 0.5 (Group B) and 5 mT (Group C) magnetic fields for two years. Animals were exposed from 5-109 weeks of age in SPF conditions according to the OECD test guideline No. 451. Average exposure was 22.6 hr/day. No significant differences in body weight and food consumption were observed between the sham and exposed groups. At the end of the exposure period, survival rates of the male rats were 73, 83, and 79%, and those of the females, 77, 79, and 75% for Groups A, B, and C, respectively, with no significant differences between groups. Differential counts of leukocytes were measured at the 52nd, 78th, and 104th weeks of exposure and no significant differences were observed between the exposure groups. All survivors were euthanized on schedule, and all the organs and tissues suspected of tumoral lesions were examined histopathologically. Incidences of mononuclear cell leukemia in the male and the female rats were 5, 4, 4 and 8, 6, 7 for Groups A, B and C, respectively; incidences of malignant lymphoma in the female rats were 0, 1 and 1. Neither significant increases nor acceleration of incidence of leukemia were observed. Incidences of brain and intracranial tumors did not increase in the exposed groups. Incidences of both benign and malignant neoplasms showed no significant difference between the exposed and sham exposed groups with one exception: fibroma of the subcutis in the male rats, which was considered not to be a statistically significant when evaluated with respect to the historical control data in our laboratory.
Keywords: Animals; Body Weight/radiation effects; *Carcinogenicity Tests/methods/statistics & numerical data; Electromagnetic Fields/*adverse effects; Female; Incidence; Leukemia, Radiation-Induced/etiology; Male; Neoplasms, Radiation-Induced/*etiology; Rats; Rats, Inbred F344; Sex Factors
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Mandeville, R., Franco, E., Sidrac-Ghali, S., Paris-Nadon, L., Rocheleau, N., Mercier, G., et al. (1997). Evaluation of the potential carcinogenicity of 60 Hz linear sinusoidal continuous-wave magnetic fields in Fischer F344 rats. FASEB J, 11(13), 1127–1136.
Abstract: Electric and magnetic fields (EMFs) associated with the production, transmission, and use of electricity are ubiquitous in industrialized societies. These fields are predominantly of low frequency (50/60 Hz) and are generally of low intensity. Review of the epidemiological evidence shows that the association between exposure to EMFs and cancer is weak and inconsistent, and generally fails to show a dose-response relationship. Moreover, in view of the methodological problems of these epidemiological studies, animal and laboratory studies are urgently needed to determine whether EMFs could be initiators and/or promoters of cancers. The objective of the present study was to determine whether chronic exposure to 60 Hz linear (single axis) sinusoidal, continuous-wave magnetic fields (MFs) of different intensities might increase the risk of leukemia and solid tumor development in rodents born and raised under these fields. Five groups of 50 female F344 rats were exposed for 20 h/day to 60 Hz MFs at intensities of <0.02 (sham controls), 2, 20, 200, and 2000 microT. Full body exposure to the different fields was administered for 104 wk starting from the prenatal period (2 days before birth) and continuing during lactation and weaning until late adult life. Body weight, survival, and clinical observations were evaluated in all groups of animals during in-life exposure. Necropsy was performed on all exposed and control animals that died, were found moribund, or were killed at termination of the study. To preserve and demonstrate the absence of any experimental bias, all clinical observations and pathological evaluations were conducted under “blinded” conditions. Fifty organs and tissues were evaluated in each animal, with special attention to the incidence of mononuclear cell leukemia, brain tumors, and mammary tumors. The findings from this chronic carcinogenicity study demonstrate that, under our defined experimental conditions, exposure to 60 Hz linear (single axis) sinusoidal, continuous wave MFs did not affect animal survival, solid tumor, or mononuclear cell leukemia development in female F344 rats. No statistically significant, consistent, positive dose-related trends with the number of tumor-bearing animals per study group could be attributed to MF exposure.
Keywords: Age Factors; Animals; Brain Neoplasms/etiology; Dose-Response Relationship, Radiation; Electromagnetic Fields/*adverse effects; Female; Incidence; Leukemia, Experimental/epidemiology/*etiology; Male; Mammary Neoplasms, Experimental/etiology; Neoplasms, Experimental/epidemiology/*etiology/pathology; Neoplasms, Radiation-Induced/*etiology; Probability; Rats; Rats, Inbred F344; Regression Analysis; Risk Factors; Time Factors
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