151
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Qian XW, Luo WH, Zheng OX. Joint effects of microwave and chromium trioxide on root tip cells of Vicia faba. J Zhejiang Univ Sci B 2006; 7:221-7. [PMID: 16502510 PMCID: PMC1419069 DOI: 10.1631/jzus.2006.b0221] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The mutagenic effects of microwave and chromium trioxide (CrO(3)) on Vicia faba root tip were studied. Micronucleus assay and chromosomal aberration assay were used to determine the mitotic index, the micronucleus frequency and chromosomal aberration frequency of Vicia faba root tip cells induced by microwave and CrO(3). The results showed that the micronucleus frequency decreased, and that the mitotic index and chromosomal aberration frequency showed linear dose responses to CrO(3), in treatment of microwave for 5 s. In microwave of 25 s, the mitotic index decreased, the micronucleus frequency and chromosomal aberration frequency increased with increase of CrO(3) concentration. We concluded that microwave and CrO(3) had antagonistic effect on the mitotic index of Vicia faba root tip cells, but had synergetic effect on micronucleus frequency and chromosomal aberration frequency of Vicia faba root tip cells.
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Affiliation(s)
- Xiao-wei Qian
- School of Life and Environmental Science, Wenzhou University, Wenzhou 325003, China.
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152
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Aaron RK, Ciombor DM, Wang S, Simon B. Clinical Biophysics: The Promotion of Skeletal Repair by Physical Forces. Ann N Y Acad Sci 2006; 1068:513-31. [PMID: 16831948 DOI: 10.1196/annals.1346.045] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Skeletal tissues respond to the physical demands of their environment by altering the synthesis and organization of the extracellular matrix. These observations have major implications for how physical environmental demands result in the clinical observations of atrophy and hypertrophy, and how manipulation of the physical environment can be used therapeutically to stimulate repair. Electrical stimulation will be considered as a paradigm of how musculoskeletal tissues respond to physical stimuli. A model of demineralized bone matrix-induced endochondral ossification has been used because it epitomizes the cell biology of endochondral bone formation in a temporally consistent way. We have studied cartilage and bone matrix production, the temporal locus of cell responsiveness, signal dosimetry, and the synthesis of signaling cytokines (TGF-beta) using biochemical, immunohistochemical, and molecular techniques. Exposure to certain electrical environments enhances chondrocyte differentiation reflected as a temporal acceleration and quantitative increase of cartilage extracellular matrix, earlier onset of osteogenesis, and more mature trabecular bone. The cell pool competent to respond resides in the mesenchymal stage. The enhancement in chondrogenesis is associated with an increase in TGF-beta synthesis mediated at least in part by binding of the transcription factor AP-1 and may be modulated specifically by phosphorylation of JNK. The clinical practice of orthopedics has empirically created a variety of biophysical environments in attempts to optimize skeletal repair. We are beginning to understand the biological effects of biophysical stimulation and are now poised to replace empiricism with treatment paradigms based upon physiologic understandings of dose and biologic response.
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Affiliation(s)
- Roy K Aaron
- Department of Orthopaedic Surgery, Brown Medical School, 100 Butler Drive, Providence, RI 02906, USA.
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153
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Del Re B, Bersani F, Mesirca P, Giorgi G. Synthesis of DnaK and GroEL in Escherichia coli cells exposed to different magnetic field signals. Bioelectrochemistry 2006; 69:99-103. [PMID: 16464648 DOI: 10.1016/j.bioelechem.2005.11.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Revised: 11/11/2005] [Accepted: 11/21/2005] [Indexed: 11/16/2022]
Abstract
The effects of extremely low frequency magnetic field (ELF-MF)(1 mT, 50 Hz) on the heat shock protein (HSP) synthesis in Escherichia coli were investigated. Two magnetic field signals were studied: sinusoidal (SMF) and pulsed square wave (PMF). It was found that bacteria exposed to SMF showed a significantly higher level of DnaK and GroEL proteins as compared to sham-exposed bacteria as revealed by Western blot, whereas a lower level was observed after PMF exposure. Similar results were obtained when bacterial cells were exposed to heat shock (HS) after ELF-MF exposure: again SMF and PMF resulted in an increase and in a reduction of HSP amount in comparison with sham control, respectively. In conclusion, the MF influences the synthesis of HSPs in E. coli in a way that critically depends on the signal characteristics.
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Affiliation(s)
- Brunella Del Re
- Department of Evolutionary Experimental Biology, University of Bologna, via Selmi 3, 40126 Bologna, Italy
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154
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McCreary CR, Dixon SJ, Fraher LJ, Carson JJL, Prato FS. Real-time measurement of cytosolic free calcium concentration in Jurkat cells during ELF magnetic field exposure and evaluation of the role of cell cycle. Bioelectromagnetics 2006; 27:354-64. [PMID: 16715520 DOI: 10.1002/bem.20248] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Extremely low frequency magnetic fields (ELF MF) have been reported to alter a number of cell signaling pathways, including those involved in proliferation, differentiation and apoptosis where cytosolic free calcium ([Ca(2+)](c)) plays an important role. To better understand the biological conditions under which ELF MF exposure might alter [Ca(2+)](c), we measured [Ca(2+)](c) by ratiometric fluorescence spectrophotometry during exposure to ELF MF in Jurkat E6.1 cells synchronized to different phases of the cell cycle. Suspensions of cells were exposed either to a near zero MF (Null) or a 60 Hz, 100 microT sinusoidal MF superimposed upon a collinear 78.1 microT static MF (AC + DC). An initial series of experiments indicated that the maximum increase in [Ca(2+)](c) above baseline after stimulation with anti-CD3 was significantly higher in samples exposed to AC + DC (n = 30) compared to Null (n = 30) with the largest difference in G2-M enriched samples. However, in a second study with G2-M enriched cells, samples treated with AC + DC (n = 17) were not statistically different from Null-treated samples (n = 27). Detailed analysis revealed that the dynamics in [Ca(2+)](c) before and after stimulation with anti-CD3 were dissimilar between Null samples from each study. From the results, we concluded (i) that the ELF MF increased [Ca(2+)](c) during an antibody-induced signaling event, (ii) that the ELF MF effect did not depend to a large degree on cell cycle, and (iii) that a field-related change in [Ca(2+)](c) signaling appeared to correlate with features in the [Ca(2+)](c) dynamics. Future work could evaluate [Ca(2+)](c) dynamics in relation to the phase of the cell cycle and inter-study variation, which may reveal factors important for the observation of real-time effects of ELF MF on [Ca(2+)](c).
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Affiliation(s)
- Cheryl R McCreary
- Imaging Program, Lawson Health Research Institute, London, Ontario, Canada
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155
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Radical Scavengers Suppress Low Frequency EMF Enhanced Proliferation in Cultured Cells and Stress Effects in Higher Plants. ACTA ACUST UNITED AC 2005. [DOI: 10.1007/s10669-005-4272-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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156
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Luceri C, De Filippo C, Giovannelli L, Blangiardo M, Cavalieri D, Aglietti F, Pampaloni M, Andreuccetti D, Pieri L, Bambi F, Biggeri A, Dolara P. Extremely Low-Frequency Electromagnetic Fields do not Affect DNA Damage and Gene Expression Profiles of Yeast and Human Lymphocytes. Radiat Res 2005; 164:277-85. [PMID: 16137200 DOI: 10.1667/rr3426.1] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We studied the effects of extremely low-frequency (50 Hz) electromagnetic fields (EMFs) on peripheral human blood lymphocytes and DBY747 Saccharomyces cerevisiae. Graded exposure to 50 Hz magnetic flux density was obtained with a Helmholtz coil system set at 1, 10 or 100 microT for 18 h. The effects of EMFs on DNA damage were studied with the single-cell gel electrophoresis assay (comet assay) in lymphocytes. Gene expression profiles of EMF-exposed human and yeast cells were evaluated with DNA microarrays containing 13,971 and 6,212 oligonucleotides, respectively. After exposure to the EMF, we did not observe an increase in the amount of strand breaks or oxidated DNA bases relative to controls or a variation in gene expression profiles. The results suggest that extremely low-frequency EMFs do not induce DNA damage or affect gene expression in these two different eukaryotic cell systems.
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Affiliation(s)
- Cristina Luceri
- Department of Pharmacology, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy.
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157
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Morelli A, Ravera S, Panfoli I, Pepe IM. Effects of extremely low frequency electromagnetic fields on membrane-associated enzymes. Arch Biochem Biophys 2005; 441:191-8. [PMID: 16126157 DOI: 10.1016/j.abb.2005.07.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Accepted: 07/23/2005] [Indexed: 10/25/2022]
Abstract
The effects of extremely low frequency electromagnetic fields of 75 Hz were studied on different membrane-associated enzymes. Only the activities of three enzymes out of seven exposed to the field decreased approximately of about 54-61% with field amplitudes above a threshold of 73-151 microT depending on the enzyme. The same field had no effect on the activities of either integral membrane enzymes such as Ca,ATPase, Na/K,ATPase, and succinic dehydrogenase or peripheral membrane enzymes such as photoreceptor PDE. The decrease in enzymatic activity of the field-sensitive enzymes was independent of the time of permanence in the field and was completely reversible. When these enzymes were solubilized with Triton, no effect of the field was obtained on the enzymatic activity, suggesting the crucial role of the membrane in determining the conditions for enzyme inactivation. The role of the particular linkage of the field-sensitive enzymes to the membranes is also discussed.
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Affiliation(s)
- A Morelli
- Department of DIBISAA, University of Genoa, viale Benedetto XV, 3 Genova 16131, Italy
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158
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Koyama S, Nakahara T, Sakurai T, Komatsubara Y, Isozumi Y, Miyakoshi J. Combined exposure of ELF magnetic fields and x-rays increased mutant yields compared with x-rays alone in pTN89 plasmids. JOURNAL OF RADIATION RESEARCH 2005; 46:257-64. [PMID: 15988145 DOI: 10.1269/jrr.46.257] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We have examined mutations in the supF gene carried by pTN89 plasmids in Escherichia coli (E. coli) to examine the effects of extremely low frequency magnetic fields (ELFMFs) and/or X-rays to the plasmids. The plasmids were subjected to sham exposure or exposed to an ELFMF (5 mT), with or without X-ray irradiation (10 Gy). For the combined treatments, exposure to the ELFMF was immediately before or after X-ray irradiation. The mutant fractions were 0.94x10(-5 )for X-rays alone, 1.58x10(-5) for an ELFMF followed by X-rays, and 3.64x10(-5) for X-rays followed by an ELFMF. Increased mutant fraction was not detected following exposure to a magnetic field alone, or after sham exposure. The mutant fraction for X-rays followed by an ELFMF was significantly higher than those of other treatments. Sequence analysis of the supF mutant plasmids revealed that base substitutions were dominant on exposure to X-rays alone and X-rays plus an ELFMF. Several types of deletions were detected in only the combined treatments, but not with X-rays alone. We could not find any mutant colonies in sham irradiated and an ELFMF alone treatment, but exposure to ELFMFs immediately before or after X-ray irradiation may enhance the mutations. Our results indicate that an ELFMF increases mutation and alters the spectrum of mutations.
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Affiliation(s)
- Shin Koyama
- Department of Radiological Technology, School of Health Sciences, Faculty of Medicine, Hirosaki University, Japan
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159
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Rosenspire AJ, Kindzelskii AL, Simon BJ, Petty HR. Real-time control of neutrophil metabolism by very weak ultra-low frequency pulsed magnetic fields. Biophys J 2005; 88:3334-47. [PMID: 15749780 PMCID: PMC1305481 DOI: 10.1529/biophysj.104.056663] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In adherent and motile neutrophils NAD(P)H concentration, flavoprotein redox potential, and production of reactive oxygen species and nitric oxide, are all periodic and exhibit defined phase relationships to an underlying metabolic oscillation of approximately 20 s. Utilizing fluorescence microscopy, we have shown in real-time, on the single cell level, that the system is sensitive to externally applied periodically pulsed weak magnetic fields matched in frequency to the metabolic oscillation. Depending upon the phase relationship of the magnetic pulses to the metabolic oscillation, the magnetic pulses serve to either increase the amplitude of the NAD(P)H and flavoprotein oscillations, and the rate of production of reactive oxygen species and nitric oxide or, alternatively, collapse the metabolic oscillations and curtail production of reactive oxygen species and nitric oxide. Significantly, we demonstrate that the cells do not directly respond to the magnetic fields, but instead are sensitive to the electric fields which the pulsed magnetic fields induce. These weak electric fields likely tap into an endogenous signaling pathway involving calcium channels in the plasma membrane. We estimate that the threshold which induced electric fields must attain to influence cell metabolism is of the order of 10(-4) V/m.
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Affiliation(s)
- Allen J Rosenspire
- Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202, USA.
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160
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Wolf FI, Torsello A, Tedesco B, Fasanella S, Boninsegna A, D'Ascenzo M, Grassi C, Azzena GB, Cittadini A. 50-Hz extremely low frequency electromagnetic fields enhance cell proliferation and DNA damage: possible involvement of a redox mechanism. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1743:120-9. [PMID: 15777847 DOI: 10.1016/j.bbamcr.2004.09.005] [Citation(s) in RCA: 188] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2004] [Revised: 09/02/2004] [Accepted: 09/08/2004] [Indexed: 11/18/2022]
Abstract
HL-60 leukemia cells, Rat-1 fibroblasts and WI-38 diploid fibroblasts were exposed for 24-72 h to 0.5-1.0-mT 50-Hz extremely low frequency electromagnetic field (ELF-EMF). This treatment induced a dose-dependent increase in the proliferation rate of all cell types, namely about 30% increase of cell proliferation after 72-h exposure to 1.0 mT. This was accompanied by increased percentage of cells in the S-phase after 12- and 48-h exposure. The ability of ELF-EMF to induce DNA damage was also investigated by measuring DNA strand breaks. A dose-dependent increase in DNA damage was observed in all cell lines, with two peaks occurring at 24 and 72 h. A similar pattern of DNA damage was observed by measuring formation of 8-OHdG adducts. The effects of ELF-EMF on cell proliferation and DNA damage were prevented by pretreatment of cells with an antioxidant like alpha-tocopherol, suggesting that redox reactions were involved. Accordingly, Rat-1 fibroblasts that had been exposed to ELF-EMF for 3 or 24 h exhibited a significant increase in dichlorofluorescein-detectable reactive oxygen species, which was blunted by alpha-tocopherol pretreatment. Cells exposed to ELF-EMF and examined as early as 6 h after treatment initiation also exhibited modifications of NF kappa B-related proteins (p65-p50 and I kappa B alpha), which were suggestive of increased formation of p65-p50 or p65-p65 active forms, a process usually attributed to redox reactions. These results suggest that ELF-EMF influence proliferation and DNA damage in both normal and tumor cells through the action of free radical species. This information may be of value for appraising the pathophysiologic consequences of an exposure to ELF-EMF.
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Affiliation(s)
- Federica I Wolf
- Institute of General Pathology and Giovanni XXIII Cancer Research Center, L.go F. Vito, 1-00168 Rome, Italy.
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161
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Ravera S, Repaci E, Morelli A, Pepe IM, Botter R, Beruto D. Effects of extremely low frequency electromagnetic fields on the adenylate kinase activity of rod outer segment of bovine retina. Bioelectromagnetics 2005; 25:545-51. [PMID: 15376242 DOI: 10.1002/bem.20031] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Extremely low frequency electromagnetic fields (ELF-EMFs) of 75 Hz with amplitudes above a threshold of about 125 microT have a dramatic effect on the adenylate kinase (AK) activity of the rod outer segment (ROS) membranes. In fact, the ATP production by ROS membranes or by purified disk membranes placed in the field decreased by approximately 54%. The decrease in enzymatic activity was independent of the time of exposure to the field and was completely reversible. When disk membranes were solubilized with Triton or a soluble isoform of AK was used, negligible effects of the field were obtained on the enzymatic activity, suggesting that the membrane has an important role in determining the conditions for the enzyme inactivation.
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Affiliation(s)
- S Ravera
- Department of DIBISAA, University of Genoa, Genoa, Italy
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162
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Hore PJ. Rapporteur's report: sources and interaction mechanisms. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2005; 87:205-12. [PMID: 15556659 DOI: 10.1016/j.pbiomolbio.2004.08.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This, the first session of the Workshop, focussed on sources of exposure to and interaction mechanisms of intense static magnetic fields. The four presentations dealt with (1) the magnetic fields produced by diagnostic magnetic resonance imaging systems; (2) the ways in which static magnetic fields can interact with matter, in particular human tissue; (3) the effects of magnetic fields on enzyme reaction rates; and (4) working practices for high-field magnet development.
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Affiliation(s)
- P J Hore
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ, UK.
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163
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Salamino F, Minafra R, Grano V, Diano N, Mita DG, Pontremoli S, Melloni E. Effect of extremely low frequency magnetic fields on calpain activation. Bioelectromagnetics 2005; 27:43-50. [PMID: 16283653 DOI: 10.1002/bem.20176] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The effects of low intensity, low frequency magnetic fields (MFs) on catalytic activity of the calcium dependent protease calpain was determined following the enzyme activation both in "in vitro" and "in vivo" conditions. We have observed that a 0.3 mT MF induces a significant increase in the requirement of the protease for this metal ion. This change is detectable at low [Ca(2+)] and disappears when the level of Ca(2+) is raised to saturating amounts. The observed effects are not due to transient MF(-) induced conformational changes occurring in calpain, but to direct effects of the MF on Ca(2+) ions, which become less available for the binding sites present in calpain. Altogether, these results indicate that exposure to low intensity, low frequency MFs alters the intracellular Ca(2+) "availability," thereby modifying the related cell response.
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Affiliation(s)
- Franca Salamino
- Department of Experimental Medicine-Biochemistry Section, and Centre of Excellence for Biomedical Research, University of Genoa, Viale Benedetto XV, Italy
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164
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Ravera S, Repaci E, Morelli A, Pepe IM, Botter R, Beruto D. Electromagnetic field of extremely low frequency decreased adenylate kinase activity in retinal rod outer segment membranes. Bioelectrochemistry 2004; 63:317-20. [PMID: 15110295 DOI: 10.1016/j.bioelechem.2003.10.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2003] [Revised: 09/19/2003] [Accepted: 10/06/2003] [Indexed: 10/26/2022]
Abstract
Adenylate kinase activity in rod outer segment membranes of bovine retina decreased of about 55% when exposed to an extremely low frequency electromagnetic field of 75 Hz and 250 microT. The effect was independent of the time of permanence in the field. Negligible effects of the field were found on the enzymatic activity of a soluble isoform of adenylate kinase or of rod outer segment membranes solubilized with Triton, suggesting the importance of the membrane in determining the conditions of the enzyme inactivation.
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Affiliation(s)
- S Ravera
- Department of DIBISAA, University of Genoa, Genoa, Italy
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165
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Antov Y, Barbul A, Mantsur H, Korenstein R. Electroendocytosis: exposure of cells to pulsed low electric fields enhances adsorption and uptake of macromolecules. Biophys J 2004; 88:2206-23. [PMID: 15556977 PMCID: PMC1305271 DOI: 10.1529/biophysj.104.051268] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This study demonstrates alteration of cell surface, leading to enhanced adsorption of macromolecules (bovine serum albumin (BSA), dextran, and DNA), after the exposure of cells to unipolar pulsed low electric fields (LEF). Modification of the adsorptive properties of the cell membrane also stems from the observation of LEF-induced cell-cell aggregation. Analysis of the adsorption isotherms of BSA-fluorescein isothiocyanate (FITC) to the surface of COS 5-7 cells reveals that the stimulated adsorption can be attributed to LEF-induced increase in the capacity of both specific and nonspecific binding. The enhanced adsorption was consequently followed by increased uptake. At 20 V/cm the maximal binding and subsequent uptake of BSA-FITC attached to specific sites are 6.5- and 7.4-fold higher than in controls, respectively. The nonspecific LEF-induced binding and uptake of BSA are 34- and 5.2-fold higher than in controls. LEF-enhanced adsorption is a temperature-independent process, whereas LEF-induced uptake is a temperature-dependent one that is abolished at 4 degrees C. The stimulation of adsorption and uptake is reversible, revealing similar decay kinetics at room temperature. It is suggested that electrophoretic segregation of charged components in the outer leaflet of the cell membrane is responsible for both enhanced adsorption and stimulated uptake via changes of the membrane elastic properties that enhance budding and fission processes.
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Affiliation(s)
- Yulia Antov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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166
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Capri M, Mesirca P, Remondini D, Carosella S, Pasi S, Castellani G, Franceschi C, Bersani F. 50 Hz sinusoidal magnetic fields do not affect human lymphocyte activation and proliferationin vitro. Phys Biol 2004; 1:211-9. [PMID: 16204841 DOI: 10.1088/1478-3967/1/4/003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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.
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Affiliation(s)
- Miriam Capri
- Department of Experimental Pathology, Via S Giacomo 12, University of Bologna, 40126 Bologna, Italy
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167
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Henbest KB, Kukura P, Rodgers CT, Hore PJ, Timmel CR. Radio frequency magnetic field effects on a radical recombination reaction: a diagnostic test for the radical pair mechanism. J Am Chem Soc 2004; 126:8102-3. [PMID: 15225036 DOI: 10.1021/ja048220q] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The photoinduced electron-transfer reaction of chrysene with isomers of dicyanobenzene is used to demonstrate the sensitivity of a radical recombination reaction to the orientation and frequency (5-50 MHz) of a approximately 300 muT radio frequency magnetic field in the presence of a 0-4 mT static magnetic field. The recombination yield is detected via the fluorescence of the exciplex formed exclusively from the electronic singlet state of the radical ion pair Chr*+/DCB*-. Magnetic field effects are simulated using a modified version of the gamma-COMPUTE algorithm, devised for the simulation of magic angle spinning NMR spectra of powdered samples. The response of a chemical or biological system to simultaneously applied radio frequency and static or extremely low-frequency magnetic fields could form the basis for a diagnostic test for the operation of the radical pair mechanism that would not require prior knowledge of the nature and properties of the radical reaction.
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Affiliation(s)
- Kevin B Henbest
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, Oxford OX1 3QZ, U.K
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168
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Katz E, Lioubashevski O, Willner I. Magnetic Field Effects on Cytochrome c-Mediated Bioelectrocatalytic Transformations. J Am Chem Soc 2004; 126:11088-92. [PMID: 15339195 DOI: 10.1021/ja048699m] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Constant magnetic fields affect many biological transformations, but we lack mechanistic understanding of the processes. The magnetohydrodynamic effect may account for the enhancement of bioelectrocatalytic transformations at interfaces. This is exemplified by the bioelectrocatalyzed cytochrome c-mediated reduction of oxygen and oxidation of lactate in the presence of cytochrome oxidase and lactate dehydrogenase, respectively. We observe significant magnetic field effects on the rates of bioelectrochemical transformations (ca. 3-fold increase) at the functionalized interfaces at field strengths, B, up to 1 T. We show that the limiting current is proportional to the B(1/3)C*(4/3), where C is the concentration of electroactive species. The results may have important implications on the understanding of the magnetic field effects on natural biocatalytic processes at membranes and on the enhancement of biotransformations in biotechnology.
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Affiliation(s)
- Eugenii Katz
- Contribution from the Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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169
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Simkó M, Mattsson MO. Extremely low frequency electromagnetic fields as effectors of cellular responses in vitro: Possible immune cell activation. J Cell Biochem 2004; 93:83-92. [PMID: 15352165 DOI: 10.1002/jcb.20198] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
There is presently an intense discussion if electromagnetic field (EMF) exposure has consequences for human health. This include exposure to structures and appliances that emit in the extremely low frequency (ELF) range of the electromagnetic spectrum, as well as emission coming from communication devices using the radiofrequency part of the spectrum. Biological effects of such exposures have been noted frequently, although the implication for specific health effects is not that clear. The basic interaction mechanism(s) between such fields and living matter is unknown. Numerous hypotheses have been suggested, although none is convincingly supported by experimental data. Various cellular components, processes, and systems can be affected by EMF exposure. Since it is unlikely that EMF can induce DNA damage directly, most studies have examined EMF effects on the cell membrane level, general and specific gene expression, and signal transduction pathways. In addition, a large number of studies have been performed regarding cell proliferation, cell cycle regulation, cell differentiation, metabolism, and various physiological characteristics of cells. Although 50/60 Hz EMF do not directly lead to genotoxic effects, it is possible that certain cellular processes altered by exposure to EMF indirectly affect the structure of DNA causing strand breaks and other chromosomal aberrations. The aim of this article is to present a hypothesis of a possible initial cellular event affected by exposure to ELF EMF, an event which is compatible with the multitude of effects observed after exposure. Based on an extensive literature review, we suggest that ELF EMF exposure is able to perform such activation by means of increasing levels of free radicals. Such a general activation is compatible with the diverse nature of observed effects. Free radicals are intermediates in natural processes like mitochondrial metabolism and are also a key feature of phagocytosis. Free radical release is inducible by ionizing radiation or phorbol ester treatment, both leading to genomic instability. EMF might be a stimulus to induce an "activated state" of the cell such as phagocytosis, which then enhances the release of free radicals, in turn leading to genotoxic events. We envisage that EMF exposure can cause both acute and chronic effects that are mediated by increased free radical levels: (1) Direct activation of, for example macrophages (or other cells) by short-term exposure to EMF leads to phagocytosis (or other cell specific responses) and consequently, free radical production. This pathway may be utilized to positively influence certain aspects of the immune response, and could be useful for specific therapeutic applications. (2) EMF-induced macrophage (cell) activation includes direct stimulation of free radical production. (3) An increase in the lifetime of free radicals by EMF leads to persistently elevated free radical concentrations. In general, reactions in which radicals are involved become more frequent, increasing the possibility of DNA damage. (4) Long-term EMF exposure leads to a chronically increased level of free radicals, subsequently causing an inhibition of the effects of the pineal gland hormone melatonin. Taken together, these EMF induced reactions could lead to a higher incidence of DNA damage and therefore, to an increased risk of tumour development. While the effects on melatonin and the extension of the lifetime of radicals can explain the link between EMF exposure and the incidence of for example leukaemia, the two additional mechanisms described here specifically for mouse macrophages, can explain the possible correlation between immune cell system stimulation and EMF exposure.
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Affiliation(s)
- Myrtill Simkó
- Division of Environmental Physiology, Institute of Cell Biology and Biosystems Technology, University of Rostock, Albert-Einstein-Strasse 3, D-18059 Rostock, Germany.
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170
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Grassi C, D'Ascenzo M, Torsello A, Martinotti G, Wolf F, Cittadini A, Azzena GB. Effects of 50Hz electromagnetic fields on voltage-gated Ca2+ channels and their role in modulation of neuroendocrine cell proliferation and death. Cell Calcium 2004; 35:307-15. [PMID: 15036948 DOI: 10.1016/j.ceca.2003.09.001] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2003] [Revised: 08/07/2003] [Accepted: 09/07/2003] [Indexed: 10/26/2022]
Abstract
Possible correlation between the effects of electromagnetic fields (EFs) on voltage-gated Ca(2+) channels, cell proliferation and apoptosis was investigated in neural and neuroendocrine cells. Exposure to 50 Hz EFs significantly enhanced proliferation in human neuroblastoma IMR32 (+40%) and rat pituitary GH3 cells (+38%). In IMR32 cells EF stimulation also inhibited puromycin- and H(2)O(2)-induced apoptosis (-22 and -33%, respectively). EF effects on proliferation and apoptosis were counteracted by Ca(2+) channel blockade. In whole-cell patch-clamp experiments 24-72 h exposure to EFs increased macroscopic Ba(2+)-current density in both GH3 (+67%) and IMR32 cells (+40%). Single-channel recordings showed that gating of L and N channels was instead unaffected, thus suggesting that the observed enhancement of current density was due to increased number of voltage-gated Ca(2+) channels. Western blot analysis of plasma membrane-enriched microsomal fractions of GH3 and IMR32 cells confirmed enhanced expression of Ca(2+) channel subunit alpha(1) following exposure to EFs. These data provide the first direct evidence that EFs enhance the expression of voltage-gated Ca(2+) channels on plasma membrane of the exposed cells. The consequent increase in Ca(2+) influx is likely responsible for the EF-induced modulation of neuronal cell proliferation and apoptosis.
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Affiliation(s)
- Claudio Grassi
- Institute of Human Physiology, Medical School, Catholic University S. Cuore, Largo F. Vito 1, 00168 Rome, Italy.
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171
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Aaron RK, Boyan BD, Ciombor DM, Schwartz Z, Simon BJ. Stimulation of growth factor synthesis by electric and electromagnetic fields. Clin Orthop Relat Res 2004:30-7. [PMID: 15021128 DOI: 10.1097/00003086-200402000-00006] [Citation(s) in RCA: 167] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Biophysical input, including electric and electromagnetic fields, regulate the expression of genes in connective tissue cells for structural extracellular matrix (ECM) proteins resulting in an increase in cartilage and bone production. In in vivo models and clinical situations, this can be manifested as enhanced repair and a gain in mechanical properties of the repairing tissues. The mechanisms by which cell functions are regulated by biophysical input is the subject of this review. Biophysical interactions of electric and electromagnetic fields at the cell membrane are not well understood and require considerable additional study. We review information on transmembrane signaling, channel activation and receptor stimulation or blockade. Understanding physical interactions and transmembrane signaling will most likely be necessary to establish dosing paradigms and improve therapeutic efficacy. Considerable information has been generated on an intermediary mechanism of activity - growth factor stimulation. Electric and electromagnetic fields increase gene expression for, and synthesis of, growth factors and this may function to amplify field effects through autocrine and paracrine signaling. Electric and electromagnetic fields can produce a sustained upregulation of growth factors, which enhance, but do not disorganize endochondral bone formation. Progress in the areas of signal transduction and growth factor synthesis is very rapid and future directions are suggested.
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Affiliation(s)
- Roy K Aaron
- Department of Orthopaedics, Brown Medical School, Providence, RI, USA.
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172
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Goheen SC, Gaither K, Anantatmula SM, Mong GM, Sasser LB, Lessor D. Corona discharge influences ozone concentrations near rats. Bioelectromagnetics 2004; 25:107-13. [PMID: 14735560 DOI: 10.1002/bem.10161] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ozone can be produced by corona discharge either in dry air or when one electrode is submerged in water. Since ozone is toxic, we examined whether ozone production by corona near laboratory animals could reach levels of concern. Male rats were exposed to a corona discharge and the concentration of ozone produced was measured. The resulting concentration of ozone ranged from ambient levels to 250 ppb when animals were located 1 cm from a 10 kV source. Similar ozone concentrations were observed when a grounded water source was present. Possible explanations for, as well as concerns regarding, ozone production under these conditions are discussed.
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Affiliation(s)
- Steven C Goheen
- Battelle, Pacific Northwest Laboratory, Richland, Washington 99352, USA.
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173
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Labrèche F, Goldberg MS, Valois MF, Nadon L, Richardson L, Lakhani R, Latreille B. Occupational exposures to extremely low frequency magnetic fields and postmenopausal breast cancer. Am J Ind Med 2003; 44:643-52. [PMID: 14635241 DOI: 10.1002/ajim.10264] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND The association between occupational exposure to extremely low frequency magnetic fields (ELF-MF) and risk of postmenopausal breast cancer was assessed in a case-control study. METHODS Breast cancer cases were compared to cancer controls. Interviewers elicited information on risk factors and on lifetime work history. Industrial hygienists assigned to each job average duration of exposure to ELF-MF at four levels of intensities ("none," <0.2 microT; "low," 0.2-<0.5microT; "medium," 0.5-<1microT; "high," > or =1-10microT). Unconditional logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (95% CI). RESULTS A total number of 608 cases and 667 controls participated. Adjusting for accepted breast cancer risk factors, we found an OR of 1.13 for lifetime occupational exposure to ELF-MF at medium or high intensities. Risks were larger for exposures before age 35 (OR = 1.40), and statistically significant for exposures before 35 among cases with progesterone receptor positive tumors (OR = 1.56, 95% CI=1.02-2.39). CONCLUSIONS There appears to be a small increased risk for breast cancer among postmenopausal women exposed occupationally to ELF-MF.
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Affiliation(s)
- France Labrèche
- Montreal Department of Public Health, Montreal, Quebec, Canada.
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174
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Pirozzoli MC, Marino C, Lovisolo GA, Laconi C, Mosiello L, Negroni A. Effects of 50 Hz electromagnetic field exposure on apoptosis and differentiation in a neuroblastoma cell line. Bioelectromagnetics 2003; 24:510-6. [PMID: 12955756 DOI: 10.1002/bem.10130] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Experiments were carried out to assess whether a magnetic field of 50 Hz and 1 mT can influence apoptosis and proliferation in the human neuroblastoma cell line LAN-5. TUNEL assays and poly-ADP ribose polymerase (PARP) expression analysis were performed to test apoptosis induction, and the WST-1 assay was used to calculate the proliferation index in a long term exposure. No alterations were found in cellular ability to undergo programmed cell death, but a small increase in the proliferation index was evidenced after 7 days of continuous exposure. Also, a slight and transient increase of B-myb oncogene expression was detected after 5 days of exposure. Combined exposures of cells to EMF and to chemical agents which interfere with proliferation, such as the differentiative agent retinoic acid and the apoptotic inducer camptothecin, showed an antagonistic effect of magnetic fields against the differentiation of the LAN-5 cells and a protective effect towards apoptosis.
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Affiliation(s)
- M C Pirozzoli
- Ente Nuove tecnologie Energia e Ambiente (ENEA) Section of Toxicology and Biomedical Sciences, Rome, Italy
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175
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Aldinucci C, Garcia JB, Palmi M, Sgaragli G, Benocci A, Meini A, Pessina F, Rossi C, Bonechi C, Pessina GP. The effect of exposure to high flux density static and pulsed magnetic fields on lymphocyte function. Bioelectromagnetics 2003; 24:373-9. [PMID: 12929155 DOI: 10.1002/bem.10111] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We investigated whether a combination of static electromagnetic field (EMF) at a flux density of 4.75 T together with pulsed EMF at a flux density of 0.7 mT generated by an NMR apparatus (NMRF), could promote movements of Ca(2+), cell proliferation, and the eventual production of proinflammatory cytokines in human lymphocytes as well as in Jurkat cells, after exposure to the field for 1 h. The same study was also performed after activation of cells with 5 micro g/ml phytohaemagglutinin (PHA) immediately before the exposure period. Our results clearly demonstrate that NMRF exposure increases the [Ca(2+)](i), without any proliferative, or activating, or proinflammatory effect on both normal and PHA stimulated lymphocytes. Accordingly, the levels of interferon gamma, tumor necrosis factor alpha, interleukin-1beta, interleukin-2, and interleukin-6 remained unvaried after exposure. Exposure of Jurkat cells statistically decreased the [Ca(2+)](i) and the proliferation. This is consistent with the low levels of IL-2 measured in supernatants of these cells after exposure. On the whole our data suggest that static and pulsed NMRF exposure contribute synergistically in the increase of the [Ca(2+)](i) without any activating or proinflammatory effect either in normal or in PHA challenged lymphocytes. In Jurkat cells, by changing the properties of cell membranes, NMRF exposure can influence Ca(2+) transport processes and hence Ca(2+) homeostasis, causing a marked decrease of proliferation.
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176
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Beraldi R, Sciamanna I, Mangiacasale R, Lorenzini R, Spadafora C. Mouse early embryos obtained by natural breeding or in vitro fertilization display a differential sensitivity to extremely low-frequency electromagnetic fields. Mutat Res 2003; 538:163-70. [PMID: 12834765 DOI: 10.1016/s1383-5718(03)00116-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We have investigated the sensitivity of pre-implantation embryos obtained by natural breeding (NB) or in vitro fertilization (IVF) to extremely low-frequency magnetic fields (ELF-MF). Fertilized eggs obtained by NB were removed from mothers 12h after mating and cultured in vitro for 5 days under continuous ELF-MF exposure (constant strength of 50Hz and various intensities, i.e. 60, 120 and 220 microT). Alternatively, zygotes obtained by IVF were subjected to ELF-MF exposure (50Hz, 60 microT), starting 12h after IVF for 5 days. We found that ELF-MF exposure causes a small yet significant (P<0.05) decrease in the survival rate of NB-derived embryos at the latest stages of pre-implantation development, i.e. the eight cell-to-blastocyst transition. In embryos exposed to the highest field intensity (220 microT), the effect became apparent somewhat earlier. When IVF-derived embryos were exposed to ELF-MF, the reduction in the rate of embryo survival was more pronounced and the difference from controls was more significant (P<0.01). Moreover, the decreased survival rate in IVF embryos became apparent as early as the first cleavage and persisted throughout pre-implantation. These results suggest that IVF-derived embryos are more sensitive than NB-generated embryos to ELF-MF, and that this sensitivity occurs earlier in development.
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177
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Nakasono S, Laramee C, Saiki H, McLeod KJ. Effect of power-frequency magnetic fields on genome-scale gene expression in Saccharomyces cerevisiae. Radiat Res 2003; 160:25-37. [PMID: 12816520 DOI: 10.1667/rr3006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
To estimate the effect of 50 Hz magnetic-field exposure on genome-wide gene expression, the yeast Saccharomyces cerevisiae was used as a model for eukaryotes. 2D PAGE (about 1,000 spots) for protein and cDNA microarray (about 5,900 genes) analysis for mRNA were performed. The cells were exposed to 50 Hz vertical magnetic fields at 10, 150 or 300 mT r.m.s. for 24 h. As positive controls, the cells were exposed to aerobic conditions, heat (40 degrees C) or minimal medium. The 2D PAGE and microarray analyses for the positive controls showed high-confidence differential expression of many genes including those for known or unknown proteins and mRNAs. For magnetic-field exposure, no high-confidence changes in expression were observed for proteins or genes that were related to heat-shock response, DNA repair, respiration, protein synthesis and the cell cycle. Principal component analysis showed no statistically significant difference in principal components, with only insignificant differences between the magnetic-field intensities studied. In contrast, the principal components for the positive controls were significantly different. The results indicate that a 50 Hz magnetic field below 300 mT did not act as a general stress factor like heat shock or DNA damage, as had been reported previously by others. This study failed to find a plausible differential gene expression that would point to a possible mechanism of an effect of magnetic fields. The findings provide no evidence that the magnetic-field exposure alters the fundamental mechanism of translation and transcription in eukaryotic cells.
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Affiliation(s)
- Satoshi Nakasono
- Bio-Science Department, Abiko Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko-City, Chiba 270-1194, Japan.
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178
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Volpe P. Interactions of zero-frequency and oscillating magnetic fields with biostructures and biosystems. Photochem Photobiol Sci 2003; 2:637-48. [PMID: 12859147 DOI: 10.1039/b212636b] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review points to the investigations concerning the effects of zero-frequency (DC) and oscillating (AC) magnetic fields (MFs) on living matter, and especially those exerted by weak DC and low-frequency/low-intensity AC MFs. Starting from the analysis of observations on the action of natural magnetic storms (MSs) or periodic geomagnetic field (GMF) variations on bacteria, plants and animals, which led to an increasing interest in MFs in general, this survey pays particular attention to the background knowledge regarding the action of artificial MFs not only at the ionic, molecular or macromolecular levels, but also at the levels of subcellular regions, in vitro cycling cells, in situ functioning tissues or organs and total bodies or entire populations. The significance of some crucial findings concerning, for instance, the MF-dependence of the nuclear or cellular volumes, rate of cell proliferation vs. that of cell death, extent of necrosis vs. that of apoptosis and cell membrane fluidity, is judged by comparing the results obtained in a solenoid (SLD), where an MF can be added to a GMF, with those obtained in a magnetically shielded room (MSR), where the MFs can be partially attenuated or null. This comparative criterion is required because the differences detected in the behaviour of the experimental samples against that of the controls are rather small per se and also because the evaluation of the data often depends upon the peculiarity of the methodologies used. Therefore, only very small differences are observed in estimating the MF-dependence of the expression of a single gene or of the rates of total DNA replication, RNA transcription and protein translation. The review considers the MF-dependence of the interactions between host eukaryotic cells and infecting bacteria, while documentation of the harmful effects of the MFs on specific life processes is reported; cases of favourable action of the MFs on a number of biological functions are also evidenced. In the framework of studies on the origin and adaptation of life on Earth or in the Universe, theoretical insights paving the way to elucidate the mechanisms of the MF interactions with biostructures and biosystems are considered.
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Affiliation(s)
- Pietro Volpe
- Department of Biology, University of Rome Tor Vergata, Rome, Italy.
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Nascimento LFC, Botura G, Mota RP. Glucose consume and growth of E. coli under electromagnetic field. Rev Inst Med Trop Sao Paulo 2003; 45:65-7. [PMID: 12754569 DOI: 10.1590/s0036-46652003000200002] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
E. coli was submitted to a 5G electromagnetic field generated by a alternate 60 Hz voltage source. The differences on growth and glucose consume in control and exposed groups were evaluated using the non-parametric Mann-Whitney U-test. There was a significant difference in glucose consume and growth in E. coli after 8 hours of exposition to electromagnetic field. It can be concluded that electromagnetic field had a positive effect in consume of glucose and growth of E. coli. The cause of these results can be explained by an increasing of glucose entrance through membrane due to the stimulated transport system via Facility Diffusion or cyclotron resonance. The growth can be caused by shortening of lag phase and excitement of log phase.
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180
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Aldinucci C, Garcia JB, Palmi M, Sgaragli G, Benocci A, Meini A, Pessina F, Rossi C, Bonechi C, Pessina GP. The effect of strong static magnetic field on lymphocytes. Bioelectromagnetics 2003; 24:109-17. [PMID: 12524677 DOI: 10.1002/bem.10071] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We investigated whether static electromagnetic fields (EMFs) at a flux density of 4.75 T, generated by an NMR apparatus (NMRF), could promote movements of Ca2+, cell proliferation, and the eventual production of proinflammatory cytokines in human peripheral blood mononuclear cells (PBMC) as well as in Jurkat cells, after exposure to the field for 1 h. The same study was also performed after activation of cells with 5 mg/ml phytohaemagglutinin (PHA). Our results clearly demonstrate that static NMRF exposure has neither proliferative, nor activating, nor proinflammatory effects on both normal and PHA activated PBMC. Moreover, the concentration of interleukin-1beta, interleukin-2, interleukin-6, interferon, and tumour necrosis factor alpha (TNFalpha) remained unvaried in exposed cells. Exposure of Jurkat cells statistically decreased the proliferation and the proliferation indexes, which 24 and 48 h after exposure were 0.7 +/- 0.29 and 0.87 +/- 0.12, respectively. Moreover, in Jurkat cells the [Ca2+]i was higher than in PBMC and was reduced significantly to about one half after exposure. This is consistent with the decrease of proliferation and with the low levels of IL-2 measured. On the whole, our data suggest that NMRF exposure failed to affect the physiologic behaviour of normal lymphomonocytes. Instead in Jurkat cells, by changing the properties of cell membranes, NMRF can influence Ca2+ transport processes, and hence Ca2+ homeostasis with improvement of proliferation.
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181
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Teodori L, Göhde W, Valente MG, Tagliaferri F, Coletti D, Perniconi B, Bergamaschi A, Cerella C, Ghibelli L. Static magnetic fields affect calcium fluxes and inhibit stress-induced apoptosis in human glioblastoma cells. CYTOMETRY 2002; 49:143-9. [PMID: 12454977 DOI: 10.1002/cyto.10172] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Epidemiologic data revealed increased brain tumor incidence in workers exposed to magnetic fields (MFs), raising concerns about the possible link between MF exposure and cancer. However, MFs seem to be neither mutagenic nor tumorigenic. The mechanism of their tumorigenic effect has not been elucidated. METHODS To evaluate the interference of MFs with physical (heat shock, HS) and chemical (etoposide, VP16) induced apoptoses, respectively, we exposed a human glioblastoma primary culture to 6 mT static MF. We investigated cytosolic Ca(2+) ([Ca(2+)](i)) fluxes and extent of apoptosis as key endpoints. The effect of MFs on HS- and VP16-induced apoptoses in primary glioblastoma cultures from four patients was also tested. RESULTS Static MFs increased the [Ca(2+)](i) from a basal value of 124 +/- 4 nM to 233 +/- 43 nM (P < 0.05). MF exposure dramatically reduced the extent of HS- and VP16-induced apoptoses in all four glioblastoma primary cultures analyzed by 56% (range, 28-87%) and 44% (range, 38-48%), respectively. However, MF alone did not exert any apoptogenic activity. Differences were observed across the four cultures with regard to apoptotic induction by HS and VP16 and to MF apoptotic reduction, with an individual variability with regard to apoptotic sensitivity. CONCLUSION The ability of static MFs to reduce the extent of damage-induced apoptosis in glioblastoma cells might allow the survival of damaged and possibly mutated cells.
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Affiliation(s)
- Laura Teodori
- UTS Biotec, Section of Biomedicine and Toxicology, ENEA, Rome, Italy.
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182
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Teodori L, Grabarek J, Smolewski P, Ghibelli L, Bergamaschi A, De Nicola M, Darzynkiewicz Z. Exposure of cells to static magnetic field accelerates loss of integrity of plasma membrane during apoptosis. CYTOMETRY 2002; 49:113-8. [PMID: 12442311 DOI: 10.1002/cyto.10160] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Much attention is being paid to the biologic effects of magnetic fields (MFs). Although MFs enhance tumorigenesis, they are neither mutagenic nor tumorigenic. The mechanism of their tumorigenic effect has not been elucidated. METHODS To investigate the effect of MFs on apoptosis in HL-60 cells, we exposed the cells to static MFs of 6 mT generated by a magnetic disk of known intensity. Apoptosis was triggered by the DNA topoisomerase I inhibitor, camptothecin (CPT). Activation of caspases in situ using the fluorochrome-labeled inhibitor (FLICA) method and determination of plasma membrane integrity by excluding propidium iodide (PI) were measured by both laser scanning cytometry (LSC) and flow cytometry (FC). LSC and FC identified cells at three sequential stages of their demise: early apoptosis (cells with activated caspases and PI negative); late apoptosis (cells with activated caspases but unable to exclude PI); secondary necrosis (cells with apoptotic morphology no longer stained with FLICA, not excluding PI). RESULTS MF alone did not induce any apoptogenic or necrogenic effect. CPT exposure led to the sequential appearance of apoptotic cells. In the presence of CPT and MF, the overall proportion of cells undergoing apoptosis was not significantly changed. However, we consistently observed a significant increase in the frequency of late apoptotic/necrotic cells when compared with samples treated with CPT alone (P < 0.001), as well as a decrease in the percentage of early apoptotic cells (P = 0.013). The data obtained by FC and LSC were consistent with each other, showing a similar phenomenon. CONCLUSION Whereas MF alone or with CPT did not affect overall cell viability, it accelerated the rate of cell transition from apoptosis to secondary necrosis after induction of apoptosis by the DNA-damaging agent, CPT. Modulation of the kinetics of the transition from apoptosis to secondary necrosis by MF in vivo may play a role in inflammation and tumorigenesis.
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Affiliation(s)
- Laura Teodori
- Department of Biomedicine and Toxicology, UTS BIOTEC, ENEA-Casaccia, Rome, Italy
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183
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Zhou J, Yao G, Zhang J, Chang Z. CREB DNA binding activation by a 50-Hz magnetic field in HL60 cells is dependent on extra- and intracellular Ca(2+) but not PKA, PKC, ERK, or p38 MAPK. Biochem Biophys Res Commun 2002; 296:1013-8. [PMID: 12200150 DOI: 10.1016/s0006-291x(02)02022-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To investigate the possible mechanism of gene transcription changes induced by magnetic field (MF), we examined the DNA binding behavior of the transcription factor cyclic-AMP responsive element binding protein (CREB) in HL60 cells after exposure to a 0.1mT 50-Hz extremely low frequency (ELF) sinusoidal MF by a gel shift assay. Magnetic field induced a time-dependent activation of CREB binding. The complex formation increased shortly after MF exposure for 10min, reaching a peak level after 1h, and then recovered to basal level at 4h after exposure. A novel MF-induced ATF2/ATF2 homodimer formation was observed after MF exposure for 30min, 1, and 2h. Furthermore, We found that the MF-induced increase of CREB DNA binding in HL60 cells was dependent on both extracellular and intracellular Ca(2+) but not PKA, PKC, ERK, or p38 MAPK by using various pathway inhibitors. These data indicate that MF exposure activates CREB DNA binding through calcium-related signal transduction pathways under our experimental conditions.
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Affiliation(s)
- Jiliang Zhou
- Laboratory of Molecular and Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, People's Republic of China
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184
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Mostafa RM, Mostafa YM, Ennaceur A. Effects of exposure to extremely low-frequency magnetic field of 2 G intensity on memory and corticosterone level in rats. Physiol Behav 2002; 76:589-95. [PMID: 12126997 DOI: 10.1016/s0031-9384(02)00730-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
In the present study, we examined the effects of chronic exposure (1 and 2 weeks) to an extremely low-frequency magnetic field (ELFMF) of 2 G intensity on memory in rats using an object recognition task. Comparable groups of rats were exposed for 1, 2 or 4 weeks to ELFMF and the following day blood samples were collected from each rat for the measurement of corticosterone level. Our results demonstrate that exposure to ELFMF induces a significant increase in the level of corticosterone in blood plasma and is associated with impairment in discrimination between familiar and novel objects.
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Affiliation(s)
- Randa M Mostafa
- Zagazig University, Banha School of Medicine, Department of Physiology, Banha, Egypt
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185
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Zhou J, Li C, Yao G, Chiang H, Chang Z. Gene expression of cytokine receptors in HL60 cells exposed to a 50 Hz magnetic field. Bioelectromagnetics 2002; 23:339-46. [PMID: 12111754 DOI: 10.1002/bem.10027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The effects of a 50 Hz extremely low frequency (ELF) sinusoidal magnetic field (MF) on the expression of genes relating to cytokine receptors were studied in HL60 cells. Transcription levels of tumor necrosis factor receptor (TNFR) p55 and p75, interleukin-6 receptor-alpha (IL-6Ralpha) and transforming growth factor-beta receptor 1 (TGFbetaR1) were quantified in cells exposed to an intensity of 0.1 or 0.8 mT for periods ranging from 30 min to 72 h. Cells treated with 10 nM of phorbol 12-myristate 13-acetate (PMA) for 8 h served as a positive control. Gene expression values were assessed by the ribonuclease protection assay (RPA) and normalized to those of the noninducible gene GAPDH. The results showed that MF exposure at 0.1 and 0.8 mT for 72 h increased TNFR p75 and IL-6Ralpha mRNA expression in HL60 cells. No significant change in gene expression levels of TNFR p55 and TGFbetaR1 was observed under any of the exposure conditions. In addition, we report here for the first time that IL-6Ralpha mRNA expression can be suppressed by PMA in HL60 cells.
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MESH Headings
- Activin Receptors, Type I/genetics
- Antigens, CD/genetics
- Gene Expression/drug effects
- HL-60 Cells
- Humans
- Magnetics/adverse effects
- Protein Serine-Threonine Kinases
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptor, Transforming Growth Factor-beta Type I
- Receptors, Cytokine/genetics
- Receptors, Interleukin-6/genetics
- Receptors, Transforming Growth Factor beta/genetics
- Receptors, Tumor Necrosis Factor/genetics
- Receptors, Tumor Necrosis Factor, Type I
- Receptors, Tumor Necrosis Factor, Type II
- Tetradecanoylphorbol Acetate/pharmacology
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Affiliation(s)
- Jiliang Zhou
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, People's Republic of China
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186
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De Mattei M, Caruso A, Pezzetti F, Pellati A, Stabellini G, Sollazzo V, Traina GC. Effects of pulsed electromagnetic fields on human articular chondrocyte proliferation. Connect Tissue Res 2002; 42:269-79. [PMID: 11913771 DOI: 10.3109/03008200109016841] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Low-energy, low-frequency pulsed electromagnetic fields (PEMFs) can induce cell proliferation in several cell culture models. In this work we analysed the proliferative response of human articular chondrocytes, cultured in medium containing 10% FBS, following prolonged exposure to PEMFs (75 Hz, 2.3 mT), currently used in the treatment of some orthopaedic pathologies. In particular, we investigated the dependence of the proliferative effects on the cell density, the availability of growth factors and the exposure lengths. We observed that PEMFs can induce cell proliferation of low density chondrocyte cultures for a long time (6 days), when fresh serum is added again in the culture medium. In the same conditions, in high density cultures, the PEMF-induced increase in cell proliferation was observed only in the first three days of exposure. The data presented in this study show that the availability of growth factors and the environmental constrictions strongly condition the cellular proliferative response to PEMFs.
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Affiliation(s)
- M De Mattei
- Dipartimento di Morfologia ed Embriologia, Università di Ferrara, Italy
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187
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Sabo J, Mirossay L, Horovcak L, Sarissky M, Mirossay A, Mojzis J. Effects of static magnetic field on human leukemic cell line HL-60. Bioelectrochemistry 2002; 56:227-31. [PMID: 12009481 DOI: 10.1016/s1567-5394(02)00027-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A number of structures with magnetic moments exists in living organisms that may be oriented by magnetic field. While most experimental efforts belong to the area of effects induced by weak and extremely low-frequency electromagnetic fields, we attempt to give an attention to the biological effects of strong static magnetic fields. The influence of static magnetic field (SMF) on metabolic activity of cells was examined. The metabolic activity retardation is observed in human leukemic cell line HL-60 exposed to 1-T SMF for 72 h. The retardation effect was observed as well as in the presence of the mixture of the antineoplastic drugs 5 fluorouracil, cisplatin, doxorubicin and vincristine.
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Affiliation(s)
- J Sabo
- Department of Medical Biophysics, Medical Faculty, P.J. Safarik University, Trieda SNP 1, 04011 Kosice, Slovak Republic.
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188
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Hu GL, Fu YD, Zeng QL, Xu ZP, Chiang H. STUDY ON GAP JUNCTIONAL INTERCELLULAR COMMUNICATION INHIBITION BY ELF MAGNETIC FIELDS USING FRAP METHOD. Electromagn Biol Med 2002. [DOI: 10.1081/jbc-120006787] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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189
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Guisasola C, Desco M, Millán O, Villanueva FJ, García-Barreno P. Biological dosimetry of magnetic resonance imaging. J Magn Reson Imaging 2002; 15:584-90. [PMID: 11997900 DOI: 10.1002/jmri.10099] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To check the bioeffects of the components of magnetic resonance imaging (MRI). MRI is based on an assumed harmless interaction between certain nuclei in the body when placed in a strong magnetic field and radio wave fields. There are three key factors actuating on the examining body: a powerful static magnetic field (SMF), magnetic gradient fields (MGFs), and pulsed radiofrequency (RF) radiation. MATERIALS AND METHODS In vitro cells (L-132 cells) were used as biosensors, and different cellular compounds were used as biomarkers (heat shock proteins [HSPs] and their messenger ribonucleic acids [mRNAs], calcium, and adenosine-3',5'-cyclic monophosphate [cAMP]). The biosensors were placed in the bore of a 1.5-T MRI machine and the different electromagnetic fields were operated. RESULTS HSPs and their mRNAs and cAMP did not respond to SMF, MGFs, or RF radiation. RF radiation increased cytosolic calcium concentration (18%, P < 0.05). CONCLUSION Although MRI procedures do not induce any cellular stress response, it may cause an unfathomable calcium increase in vitro. Although the in vitro experimental conditions are not totally comparable to clinical situations, the usefulness of the in vivo biological dosimetry, circulating leukocytes as biosensors, and HSPs and/or calcium as biomarkers is suggested.
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Affiliation(s)
- Concepción Guisasola
- Cellular Biology Laboratory, Experimental Medicine and Surgery Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain
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190
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Macrì MA, Di Luzio S, Di Luzio S. Biological effects of electromagnetic fields. Int J Immunopathol Pharmacol 2002; 15:95-105. [PMID: 12590871 DOI: 10.1177/039463200201500204] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Nowadays, concerns about hazards from electromagnetic fields represent an alarming source for human lives in technologically developed countries. We are surrounded by electromagnetic fields everywhere we spend our working hours, rest or recreational activities. The aim of this review is to summarize the biological effects due to these fields arising from power and transmission lines, electrical cable splices, electronic devices inside our homes and work-places, distribution networks and associated devices such as cellular telephones and wireless communication tower, etc. Special care has been reserved to study the biological effects of electromagnetic fields on cell lines of the mammalian immune system about which our research group has been working for several years.
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Affiliation(s)
- M. A. Macrì
- Dip. Medicina Sperimentale e Patologia, INFM, University of Rome, Italy
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191
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Richard D, Lange S, Viergutz T, Kriehuber R, Weiss DG, Myrtill S. Influence of 50 Hz electromagnetic fields in combination with a tumour promoting phorbol ester on protein kinase C and cell cycle in human cells. Mol Cell Biochem 2002; 232:133-41. [PMID: 12030371 DOI: 10.1023/a:1014802005672] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
It still is an unsolved issue whether exposure to power-line frequency electromagnetic fields (EMF) may promote carcinogenesis and if so whether it does so by influencing the proliferation, the survival, and the differentiation of cells. Since the family of protein kinases C (PKC) takes part in these processes by interacting with signal transduction pathways at several levels including the activation of transcription factors, we evaluated in the present study the effects of exposure of human amniotic fluid cells (AFC) to 50 Hz, 1 mT electromagnetic fields (EMF) alone and in combination with the tumour promoting phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) on the subcellular localization of PKC protein, on PKC enzyme activity, and on the cell cycle distribution. Quantitative analyses of the PKC expression pattern demonstrated the translocation of PKC from the cytosolic to the membrane fraction after exposure to 10, 50, 100 nM, and 1 microM TPA. EMF exposure alone showed no effect on PKC translocation. Co-exposure to 10, 50, and 100 nM TPA and I mT EMF revealed a significant additive effect (25 +/- 50, 66 +/- 29, 22 +/- 50%, respectively) with the most prominent increase at the concentration of 50 nM TPA. At the highest concentration of TPA used (1 microM) no additive effect of EMF could be observed. Data on enzymatic activity indicate that EMF modulate the PKC activity, showing a significant increase of 10 +/- 16% in total PKC activity after co-exposure to 50 nM TPA and 1 mT EMF when compared to 50 nM TPA alone. Flow cytometric analyses showed a transient cell cycle arrest in G0/G1-phase followed by a delayed transit through S-phase in response to TPA, which was, however, not enhanced by co-exposure with EMF. We conclude that in AFC cells TPA at lower concentrations (< or = 100 nM) induces a less than maximum effect on the PKC pathway, which can be enhanced by the applied EMF.
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Affiliation(s)
- Doreen Richard
- University of Rostock, Institute of Cell Biology and Biosystems Technology, Division of Environmental Physiology, Germany
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192
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Robison JG, Pendleton AR, Monson KO, Murray BK, O'Neill KL. Decreased DNA repair rates and protection from heat induced apoptosis mediated by electromagnetic field exposure. Bioelectromagnetics 2002; 23:106-12. [PMID: 11835257 DOI: 10.1002/bem.103] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In this study, we demonstrate that electromagnetic field (EMF) exposure results in protection from heat induced apoptosis in human cancer cell lines in a time dependent manner. Apoptosis protection was determined by growing HL-60, HL-60R, and Raji cell lines in a 0.15 mT 60 Hz sinusoidal EMF for time periods between 4 and 24 h. After induction of apoptosis, cells were analyzed by the neutral comet assay to determine the percentage of apoptotic cells. To discover the duration of this protection, cells were grown in the EMF for 24 h and then removed for 24 to 48 h before heat shock and neutral comet assays were performed. Our results demonstrate that EMF exposure offers significant protection from apoptosis (P<.0001 for HL-60 and HL-60R, P<.005 for Raji) after 12 h of exposure and that protection can last up to 48 h after removal from the EMF. In this study we further demonstrate the effect of the EMF on DNA repair rates. DNA repair data were gathered by exposing the same cell lines to the EMF for 24 h before damaging the exposed cells and non-exposed cells with H2O2. Cells were allowed to repair for time periods between 0 and 15 min before analysis using the alkaline comet assay. Results showed that EMF exposure significantly decreased DNA repair rates in HL-60 and HL-60R cell lines (P<.001 and P<.01 respectively), but not in the Raji cell line. Importantly, our apoptosis results show that a minimal time exposure to an EMF is needed before observed effects. This may explain previous studies showing no change in apoptosis susceptibility and repair rates when treatments and EMF exposure were administered concurrently. More research is necessary, however, before data from this in vitro study can be applied to in vivo systems.
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Affiliation(s)
- Jacob G Robison
- Department of Microbiology, Brigham Young University, Provo, Utah 84602, USA
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193
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Yamaguchi DT, Huang J, Ma D, Wang PKC. Inhibition of gap junction intercellular communication by extremely low-frequency electromagnetic fields in osteoblast-like models is dependent on cell differentiation. J Cell Physiol 2002; 190:180-8. [PMID: 11807822 DOI: 10.1002/jcp.10047] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Electromagnetic fields have been used to augment the healing of fractures because of its ability to increase new bone formation. The mechanism of how electromagnetic fields can promote new bone formation is unknown, although the interaction of electromagnetic fields with components of the plasma membrane of cells has been hypothesized to occur in bone cells. Gap junctions occur among bone forming cells, the osteoblasts, and have been hypothesized to play a role in new bone formation. Thus it was investigated whether extremely low-frequency (ELF) magnetic fields alter gap junction intercellular communication in the pre-osteoblastic model, MC3T3-E1, and the well-differentiated osteoblastic model, ROS 17/2.8. ELF magnetic field exposure systems were designed to be used for an inverted microscope stage and for a tissue culture incubator. Using these systems, it was found that magnetic fields over a frequency range from 30 to 120 Hz and field intensities up to 12.5 G dose dependently decreased gap junction intercellular communication in MC3T3-E1 cells during their proliferative phase of development. The total amount of connexin 43 protein and the distribution of connexin 43 gap junction protein between cytoplasmic and plasma membrane pools were unaltered by treatment with ELF magnetic fields. Cytosolic calcium ([Ca(2+)](i)) which can inhibit gap junction communication, was not altered by magnetic field exposure. Identical exposure conditions did not affect gap junction communication in the ROS 17/2.8 cell line and when MC3T3-E1 cells were more differentiated. Thus ELF magnetic fields may affect only less differentiated or pre-osteoblasts and not fully differentiated osteoblasts. Consequently, electromagnetic fields may aid in the repair of bone by effects exerted only on osteoprogenitor or pre-osteoblasts.
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Affiliation(s)
- Dean T Yamaguchi
- Research Service and Geriatrics Research, Education, and Clinical Center, VAMC, West Los Angeles, California, USA
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194
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Dubreuil D, Jay T, Edeline JM. Does head-only exposure to GSM-900 electromagnetic fields affect the performance of rats in spatial learning tasks? Behav Brain Res 2002; 129:203-10. [PMID: 11809512 DOI: 10.1016/s0166-4328(01)00344-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The rapid expansion of mobile communication has generated intense interest, but has also fuelled ongoing concerns. In both humans and animals, radiofrequency radiations are suspected to affect cognitive functions. More specifically, several studies performed in rodents have suggested that spatial learning can be impaired by electromagnetic field exposure. However, none of these previous studies have simulated the common conditions of GSM mobile phones use. This study is the first using a head-only exposure system emitting a 900-MHz GSM electromagnetic field (pulsed at 217 Hz). The two behavioural tasks that were evaluated here have been used previously to demonstrate performance deficits in spatial learning after electromagnetic field exposure: a classical radial maze elimination task and a spatial navigation task in an open-field arena (dry-land version of the Morris water maze). The performances of rats exposed for 45 min to a 900-MHz electromagnetic field (1 and 3.5 W/kg) were compared to those of sham-exposed and cage-control rats. There were no differences among exposed, sham, and cage-control rats in the two spatial learning tasks. The discussion focuses on the potential reasons that led previous studies to conclude that learning deficits do occur after electromagnetic field exposure.
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Affiliation(s)
- Diane Dubreuil
- Laboratoire de Neurobiologie de l'Apprentissage, de la Mémoire, et de la Communication, CNRS-UMR 8620, bât. 446, Université Paris Sud, Orsay, France.
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195
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Tonini R, Baroni MD, Masala E, Micheletti M, Ferroni A, Mazzanti M. Calcium protects differentiating neuroblastoma cells during 50 Hz electromagnetic radiation. Biophys J 2001; 81:2580-9. [PMID: 11606272 PMCID: PMC1301726 DOI: 10.1016/s0006-3495(01)75902-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Despite growing concern about electromagnetic radiation, the interaction between 50- to 60-Hz fields and biological structures remains obscure. Epidemiological studies have failed to prove a significantly correlation between exposure to radiation fields and particular pathologies. We demonstrate that a 50- to 60-Hz magnetic field interacts with cell differentiation through two opposing mechanisms: it antagonizes the shift in cell membrane surface charges that occur during the early phases of differentiation and it modulates hyperpolarizing K channels by increasing intracellular Ca. The simultaneous onset of both mechanisms prevents alterations in cell differentiation. We propose that cells are normally protected against electromagnetic insult. Pathologies may arise, however, if intracellular Ca regulation or K channel activation malfunctions.
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Affiliation(s)
- R Tonini
- Dipartimento di Fisiologia e Biochimica Generali, I(a) Università di Milano, I-20133 Milano, Italy
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196
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De Roos AJ, Teschke K, Savitz DA, Poole C, Grufferman S, Pollock BH, Olshan AF. Parental occupational exposures to electromagnetic fields and radiation and the incidence of neuroblastoma in offspring. Epidemiology 2001; 12:508-17. [PMID: 11505168 DOI: 10.1097/00001648-200109000-00008] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We examined parental occupational exposures to electromagnetic fields and radiation and the incidence of neuroblastoma in offspring. Cases were 538 children diagnosed with neuroblastoma between 1992 and 1994 in the United States or Canada. Age-matched controls were selected by random-digit dialing. Occupational exposures to electrical equipment and radiation sources were classified by an industrial hygienist, and average exposures to extremely low frequency magnetic fields were estimated using a job exposure matrix. Maternal exposure to a broad grouping of sources that produce radiofrequency radiation was associated with an increased incidence of neuroblastoma (odds ratio = 2.8; 95% confidence interval = 0.9-8.7). Paternal exposure to battery-powered forklifts was positively associated with neuroblastoma (odds ratio = 1.6; 95% confidence interval = 0.8-3.2), as were some types of equipment that emit radiofrequency radiation (odds ratios congruent with 2.0); however, the broad groupings of sources that produce ELF fields, radiofrequency radiation, or ionizing radiation were not associated with neuroblastoma. Paternal average extremely low frequency magnetic field exposure >0.4 microTesla was weakly associated with neuroblastoma (odds ratio = 1.6; 95% confidence interval = 0.9-2.8), whereas maternal exposure was not. Overall, there was scant supportive evidence of strong associations between parental exposures in electromagnetic spectrum and neuroblastoma in offspring.
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Affiliation(s)
- A J De Roos
- Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill, NC, USA.
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197
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Simkó M, Richard D, Kriehuber R, Weiss DG. Micronucleus induction in Syrian hamster embryo cells following exposure to 50 Hz magnetic fields, benzo(a)pyrene, and TPA in vitro. Mutat Res 2001; 495:43-50. [PMID: 11448641 DOI: 10.1016/s1383-5718(01)00192-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Electromagnetic fields (EMFs) have been associated with increased incidence of cancer suggested by epidemiological studies. To test the carcinogenic potency of EMF, the in vitro micronucleus assay with SHE cells has been used as a screening method for genotoxicity. A 50Hz magnetic field (MF) of 1mT field strength was applied either alone or with the tumour initiator benzo(a)pyrene (BP) or the tumour promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). All three treatments were applied in single, double or triple treatment regimes. MF or TPA (1nM) alone did not affect the number of micronuclei (MN) in initiated and non-initiated SHE cells. Changing the schedule of the typical initiation protocol, namely applying the initiator (BP) during exposure to MF, results in an 1.8-fold increased MN formation compared to BP treatment alone. Combined experiment with BP, TPA and MF did not cause further MN formation. Since initiation during MF exposure caused a significant increased MN formation, our findings suggest that MFs enhance the initiation process of BP. We think that this MF-enhanced co-carcinogenic effect is caused by an indirect "cell activation" process. The resulting genomic instability is proposed to be due to free radicals and/or to the unscheduled "switching-on" of signal transduction pathways.
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Affiliation(s)
- M Simkó
- Division of Environmental Physiology, Institute of Cell Biology and Biosystems Technology, University of Rostock, Universitätsplatz 2, D-18051 Rostock, Germany.
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198
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Woodward JR, Timmel CR, McLauchlan KA, Hore PJ. Radio frequency magnetic field effects on electron-hole recombination. PHYSICAL REVIEW LETTERS 2001; 87:077602. [PMID: 11497916 DOI: 10.1103/physrevlett.87.077602] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2000] [Indexed: 05/23/2023]
Abstract
We present measurements of the spectrum (1--80 MHz) of the effect of a weak (approximately 500 microT) radio frequency magnetic field on the electron-hole recombination of radical ion pairs in solution. Distinct spectra are observed for the pyrene anion/dimethylaniline cation radical pair in which one or both of the radicals are perdeuterated. The radical pair mechanism is developed theoretically and shown to account satisfactorily for both the magnetic field effect and the associated magnetic isotope effect.
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Affiliation(s)
- J R Woodward
- Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ, United Kingdom
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199
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Simkó M, Droste S, Kriehuber R, Weiss DG. Stimulation of phagocytosis and free radical production in murine macrophages by 50 Hz electromagnetic fields. Eur J Cell Biol 2001; 80:562-6. [PMID: 11561907 DOI: 10.1078/0171-9335-00187] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Effects of 50 Hz electromagnetic fields on phagocytosis and free radical production were examined in mouse bone marrow-derived macrophages. Macrophages were in vitro exposed to electromagnetic fields using different magnetic field densities (0.5-1.5 mT). Short-time exposure (45 min) to electromagnetic fields resulted in significantly increased phagocytic uptake (36.3% +/- 15.1%) as quantified by measuring the internalization rate of latex beads. Stimulation with 1 nM 12-0-tetradecanoylphorbol-13-acetate (TPA) showed the same increased phagocytic activity as 1 mT electromagnetic fields. However, co-exposure to electromagnetic fields and TPA showed no further increase of bead uptake, and therefore we concluded that because of the absence of additive effects, the electromagnetic fields-induced stimulation of mouse bone marrow-derived macrophages does not involve the protein kinase C signal transduction pathway. Furthermore, a significant increased superoxide production after exposure to electromagnetic fields was detected.
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Affiliation(s)
- M Simkó
- University of Rostock, Institute of Cell Biology and Biosystems Technology, Division of Environmental Physiology, Germany.
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200
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Huuskonen H, Juutilainen J, Komulainen H. Development of preimplantation mouse embryos after exposure to a 50 Hz magnetic field in vitro. Toxicol Lett 2001; 122:149-55. [PMID: 11439221 DOI: 10.1016/s0378-4274(01)00362-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Effect of sinusoidal 50 Hz magnetic field (MF) on development of preimplantation CBA/S mouse embryos in vitro was studied. Superovulated and in vivo fertilized preimplantation embryos were collected at one cell stage and divided to control and MF-exposed groups. Sinusoidal 50 Hz MF with field strength of 10 A/m r.m.s., corresponding a flux density of 13 microT r.m.s., was used to expose the embryos in culture at 37 degrees C in a CO2-incubator. The developmental stage and abnormalities were recorded twice daily except once daily during weekends. The vitality and developmental stages of the embryos were similar in both groups although slightly more dead embryos were found during the 1st day in MF-exposed group (P<0.05) and the development of MF-exposed embryos was slightly impaired. In conclusion, the exposure to sinusoidal 50 Hz MF at field strength of 10 A/m did not significantly disturb the development of the mouse embryos in vitro up to the blastocyst stage.
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Affiliation(s)
- H Huuskonen
- National Public Health Institute, Department of Environmental Health, Laboratory of Toxicology, P.O. Box 95, FIN-70701, Kuopio, Finland.
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