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Hanoun, M., Eisele, L., Suzuki, M., Greally, J. M., Hüttmann, A., Aydin, S., et al. (2012). Epigenetic Silencing of the Circadian Clock Gene CRY1 is Associated with an Indolent Clinical Course in Chronic Lymphocytic Leukemia. PLoS ONE, 7(3), e34347.
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Cui, Y., Ge, Z., Rizak, J. D., Zhai, C., Zhou, Z., Gong, S., et al. (2012). Deficits in water maze performance and oxidative stress in the hippocampus and striatum induced by extremely low frequency magnetic field exposure. PLoS One, 7(5), e32196.
Abstract: The exposures to extremely low frequency magnetic field (ELF-MF) in our environment have dramatically increased. Epidemiological studies suggest that there is a possible association between ELF-MF exposure and increased risks of cardiovascular disease, cancers and neurodegenerative disorders. Animal studies show that ELF-MF exposure may interfere with the activity of brain cells, generate behavioral and cognitive disturbances, and produce deficits in attention, perception and spatial learning. Although, many research efforts have been focused on the interaction between ELF-MF exposure and the central nervous system, the mechanism of interaction is still unknown. In this study, we examined the effects of ELF-MF exposure on learning in mice using two water maze tasks and on some parameters indicative of oxidative stress in the hippocampus and striatum. We found that ELF-MF exposure (1 mT, 50 Hz) induced serious oxidative stress in the hippocampus and striatum and impaired hippocampal-dependent spatial learning and striatum-dependent habit learning. This study provides evidence for the association between the impairment of learning and the oxidative stress in hippocampus and striatum induced by ELF-MF exposure.
Keywords: Animals; Body Weight; Corpus Striatum/enzymology/*metabolism; Hippocampus/enzymology/*metabolism; Magnetic Fields/*adverse effects; Male; *Maze Learning; Mice; Mice, Inbred C57BL; Motor Activity; *Oxidative Stress
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Jiang, B., Nie, J., Zhou, Z., Zhang, J., Tong, J., & Cao, Y. (2012). Adaptive response in mice exposed to 900 MHz radiofrequency fields: primary DNA damage. PLoS One, 7(2), e32040.
Abstract: The phenomenon of adaptive response (AR) in animal and human cells exposed to ionizing radiation is well documented in scientific literature. We have examined whether such AR could be induced in mice exposed to non-ionizing radiofrequency fields (RF) used for wireless communications. Mice were pre-exposed to 900 MHz RF at 120 microW/cm(2) power density for 4 hours/day for 1, 3, 5, 7 and 14 days and then subjected to an acute dose of 3 Gy gamma-radiation. The primary DNA damage in the form of alkali labile base damage and single strand breaks in the DNA of peripheral blood leukocytes was determined using the alkaline comet assay. The results indicated that the extent of damage in mice which were pre-exposed to RF for 1 day and then subjected to gamma-radiation was similar and not significantly different from those exposed to gamma-radiation alone. However, mice which were pre-exposed to RF for 3, 5, 7 and 14 days showed progressively decreased damage and was significantly different from those exposed to gamma-radiation alone. Thus, the data indicated that RF pre-exposure is capable of inducing AR and suggested that the pre-exposure for more than 4 hours for 1 day is necessary to elicit such AR.
Keywords: Animals; Comet Assay; DNA Damage/*radiation effects; Gamma Rays/adverse effects; Male; Mice; Mice, Inbred ICR; Radio Waves/*adverse effects
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Uckun, F. M., Kurosaki, T., Jin, J., Jun, X., Morgan, A., Takata, M., et al. (1995). Exposure of B-lineage lymphoid cells to low energy electromagnetic fields stimulates Lyn kinase. J Biol Chem, 270(46), 27666–27670.
Abstract: Here, we present evidence that exposure of B-lineage lymphoid cells to low energy electromagnetic fields (EMF) stimulates the protein tyrosine kinases Lyn and Syk, results in tyrosine phosphorylation of multiple electrophoretically distinct substrates, and leads to downstream activation of protein kinase C (PKC). EMF exposure enhances protein tyrosine phosphorylation in Syk deficient but not in Lyn-deficient B-lineage lymphoid cells and stimulates Lyn kinase activity in wild-type as well as Syk-deficient B-lineage lymphoid cells. These results indicate that activation of Lyn kinase is sufficient and mandatory for EMF-induced tyrosine phosphorylation in B-lineage lymphoid cells. The PKC activity increases later than the Lyn activity and pretreatment with the PTK inhibitors genistein or herbimycin A abrogates the EMF-induced PKC signal. Thus, stimulation of Lyn is a proximal and mandatory step in EMF-induced activation of PKC in B-lineage lymphoid cells. Our observations prompt the hypothesis that a delicate growth regulatory balance might be altered in B-lineage lymphoid cells by EMF-induced activation of Lyn.
Keywords: Amino Acid Sequence; B-Lymphocytes/enzymology/*radiation effects; Benzoquinones; Cell Line; *Electromagnetic Fields; Enzyme Inhibitors/pharmacology; Enzyme Precursors/deficiency; Genistein; Humans; Intracellular Signaling Peptides and Proteins; Isoflavones/pharmacology; Lactams, Macrocyclic; Molecular Sequence Data; Myelin Basic Protein/metabolism; Peptide Fragments/chemistry/metabolism; Phosphoproteins/isolation & purification/metabolism; Phosphotyrosine/analysis; Protein Kinase C/metabolism; Protein-Tyrosine Kinases/antagonists & inhibitors/deficiency/*metabolism/radiation effects; Quinones/pharmacology
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Muller, P., & Ahmad, M. (2011). Light-activated cryptochrome reacts with molecular oxygen to form a flavin-superoxide radical pair consistent with magnetoreception. J Biol Chem, 286(24), 21033–21040.
Abstract: Cryptochromes are flavin-based photoreceptors occurring throughout the biological kingdom, which regulate growth and development in plants and are involved in the entrainment of circadian rhythms of both plants and animals. A number of recent theoretical works suggest that cryptochromes might also be the receptors responsible for the sensing of the magnetic field of the earth (e.g. in insects, migratory birds, or migratory fish). Cryptochromes undergo forward light-induced reactions involving electron transfer to excited state flavin to generate radical intermediates, which correlate with biological activity. Here, we give evidence of a mechanism for the reverse reaction, namely dark reoxidation of protein-bound flavin in Arabidopsis thaliana cryptochrome (AtCRY1) by molecular oxygen that involves formation of a spin-correlated FADH(*)-superoxide radical pair. Formation of analogous radical pairs in animal cryptochromes might enable them to function as magnetoreceptors.
Keywords: Animals; Arabidopsis/metabolism; Cryptochromes/*chemistry; Drosophila; Electrodes; Flavins/*chemistry; Humans; Light; Magnetics; Oxygen/chemistry; Oxygen Consumption; Reactive Oxygen Species; Signal Transduction; Spectrophotometry, Ultraviolet/methods; Superoxides/*chemistry
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