Magnetic fields at extremely low-frequency (50Hz, 0.8mT) can induce the uptake of intracellular calcium levels in osteoblasts (original) (raw)
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Combined magnetic fields increased net calcium flux in bone cells
Calcified Tissue International, 1994
Low energy electromagnetic fields (EMF) exhibit a large number of biological effects. A major issue to be determined is "What is the lowest threshold of detection in which cells can respond to an EMF?" In these studies we demonstrate that a low-amplitude combined magnetic field (CMF) which induces a maximum potential gradient of 10 -5 V/m is capable of increasing net calcium flux in human osteoblast-like cells. The increase in net calcium flux was frequency dependent, with a peak in the 15.3-16.3 Hz range with an apparent bandwidth of approximately 1 Hz. A model that characterizes the thermal noise limit indicates that nonspherical cell shape, resonant type dynamics, and signal averaging may all play a role in the transduction of lowamplitude EMF effects in biological systems.
Bioelectromagnetics, 1995
Low-frequency magnetic fields (MF) can increase the cytosolic calcium concentration ([Ca'+]) in lymphocytes in the same manner as a physiological stimulus such as antibodies directed towards the CD3 complex. In this study, MF with various frequencies and flux densities were used, while [Ca'+], changes were recorded using microfluorometry with fura-2 as a probe. The applied sinusoidal M F induced oscillatory changes of [Ca"], in the leukemic cell line Jurkat in a manner similar to that seen with stimulation by antibodies. The response at 0.15 mT was over a frequency range from 5 to 100 Hz, with a fairly broad peak having its maximum at 50 Hz. The result of testing increasing flux densities at 50 HI. was a threshold response with no effect below 0.04 mT and a plateau at 0.15 mT. On the basis of the characteristic calcium pattern resulting from an applied MF, we suggest that MF influence molecular events in regular signal transduction pathways of T cells.
FEBS Letters, 1992
The effect of ~-HZ, monopolar, quasi-rectangular mngnctic field pulsea on '"Cn?' uptake in resting and mitogen.treated rat thymic lymphocytes was evalunted. A 30.min, non-thermal cxposurc to the pulsed magnetic field (Bmk = 6.5 mT, f&, = 0.69 mV/cm, J,,, = 2.6 PA/cm') reduced Concanavalin A-induced "'Cn"' uptnkc by 45%. It was observed that (i) the induction of lhe ~-HZ field response dependend on Caz+ signal transduction activation; (ii) the response direction (stimulation or inhibition) depended on lbe level of lymphocyte mitogen responsiveness, and (iii) the field response magnitude increased with incrensing magnetic field flux densities &.,,, = 0, 1.6, 6.5 and 28 mT). Our results demonstmte field elkc~s a &,,, nearly IO" greater than that of the average human environment for low-frequency mngnetic fields and they are consistent with the independent results from other ~-HZ pulsed magnetic field studies with lymphocytes.
Electromagnetic field effects on cells of the immune system: the role of calcium signaling 1
The FASEB Journal, 1992
?magnetic fI4d efl'ccts on ee11soft1 t1*1e of calcium signaling J 1LLECZW ,Rs#{231}ardMedicine nd Radiation Bigpltyeics Dvssion, Lawencc Bei*dey &xkdcy Cahfornia 9472OL USA immune sten; abatory, unkvcreity of Cei1ittnia ABSTRACT During the past decade considerable evidence has accumulated demonstrating that nonthermal exposures of cells of the immune system to extremely lowfrequency (ELF) electromagnetic fields (< 300 Hz) can elicit cellular changes that might be relevant to in vivo immune activity. A similar responsiveness to nonionizing electromagnetic energy in this frequency range has also been documented for tissues of the neuroendocrine and musculoskeletal system. However, knowledge about the underlying biological mechanisms by which such fields can induce cellular changes is still very limited. It is generally believed that the cell membrane and Ca2-regulated activity is involved in bioactive ELF field coupling to living systems. This article begins with a short review of the current state of knowledge concerning the effects of nonthermal levels of ELF electromagnetic fields on the biochemistry and activity of immune cells and then closely examines new results that suggest a role for Ca2 in the induction of these cellular field effects. Based on these findings it is proposed that membranemediated Ca2 signaling processes are involved in the mediation of field effects on the immune system.-Walleczek, J. Electromagnetic field effects on cells of the immune system: the role of calcium signaling.
Is the Ca2+ transport of human erythrocytes influenced by ELF- and MF-electromagnetic fields?
Bioelectrochemistry and Bioenergetics, 1998
In about 400 double experiments, the influence of electromagnetic fields between 15 Hz and 12 kHz on the active calcium pump Ž. Ca,Mg-ATPase of human erythrocytes was investigated. Each experiment includes the fitting of the efflux kinetics synchronously in two identical equipments, with two parts of the same erythrocyte suspension, one with field, one as untreated control. No clear effect on the Ž. activity of the Ca,Mg-ATPase of human erythrocytes could be found, neither for magnetic sinusoidal fields up to 2.6 mT peak , nor for Ž. AC fields supported by a static magnetic field 3.9 mT SMFq 3.9 mT, 1 kHz , nor for directly applied electric fields up to 150 Vrm. The Arrhenius plot of the rate constants show a transition at 238C, but no temperature-dependent field effect could be found. Several Ž points, supported by 10 to 20 experiments show a small, but significant decrease in the rate constant of the efflux 45 Hz, 740 Hz, 1040. Hz , but this could not be confirmed by experiments at 620, 920 and 1540 Hz. The statistical deviation of the field effects in the region between 520 and 1540 Hz of the experiments with magnetic fields are significantly larger than for experiments with other frequencies and from such with the electrode system, whereas the deviation of the rate constants themselves are always the same.
Iberoamerican Journal of Medicine
Introduction: Alternating and pulsed electromagnetic magnetic fields (AEMF and PEMF) of different amplitudes and frequencies can induce metabolic and proliferative effects in osteoblasts, but there is no clearly directed tendency of these effects. I hypothesize that there are extremely low triggering parameters of alternating electromagnetic field (EMF) intensity, i.e., above the background magnetic field on earth but below the lowest AEMF and PEMF that have been investigated to date (above 0.07 mT and below 0.4 mT) that induce cellular response. Methods: Accordingly, human monolayer explant culture replica were exposed four times in 24-hour intervals to two minutes of 10 kHz AEMF or PEMF (10 Hz pulses at a basic 5 kHz frequency) with a maximal EMF intensity of 0.2 mT for both. Cell proliferation was estimated from microscopic cell counting and cell death by lactate dehydrogenase (LDH) specific activity in culture media (measured using a colorimetric method). The early marker of ost...
Calcium is necessary in the cell response to EM fields
FEBS Letters, 1994
Previous research showed that exposure of human HL-60 cells to extremely low frequency electromagnetic fields increases the steady-state levels of some mRNAs. Modifications in calcium flux have been suggested as a means of amplifying electromagnetic signals, and induced changes in calcium intlux could hypothetically lead to gene activation. The present experiments tested the role of calcium in the response of cells to electromagnetic fields. Steady state transcript levels for c-fos and c-myc were determined under conditions of low extracellular calcium. The present study confirms that calcium plays a role in the response of cells to electromagnetic fields.
Bioelectromagnetics, 1985
Two independent laboratories have demonstrated that electromagnetic radiation at specific frequencies can cause a change in the efflux of calcium ions from brain tissue in vitro. In a local geomagnetic field (LGF) at a density of 38 microTesla (pT), 15and 45-Hz electromagnetic signals (40 V,,lm in air) have been shown to induce a change in the efflux of calcium ions from the exposed tissues, whereas 1-and 30-Hz signals do not. We now show that the effective 15-Hz signal can be rendered ineffective when the LGF is reduced to 19 pT with Helmholtz coils. In addition, the ineffective 30-Hz signal becomes effective when the LGF is changed to k25.3 pT or to +76 pT. These results demonstrate that the net intensity of the LGF is an important variable. The results appear to describe a resonance-like relationship in which the frequency of the electromagnetic field that can induce a change in efflux is proportional to a product of LGF density and an index, 2n + 1, where n = 0,l. These phenomenological findings may provide a basis for evaluating the apparent lack of reproducibility of biological effects caused by low-intensity extremelylow-frequency (ELF) electromagnetic signals. In future investigations of this phenomenon, the LGF vector should be explicitly described. If the underlying mechanism involves a general property of tissue, then research conducted in the ambient electromagnetic environment (50160 Hz) may be subjected to unnoticed and uncontrolled influences, depending on the density of the LGF.
Physiological Research, 2007
Effects of electromagnetic fields (EMFs) on human cell lines were described in numerous studies, but still many questions remain unanswered. Our experiment was designed with the aim of studying the effects of EMFs on the metabolic activity of chondrocytes in vitro. Human chondrocyte in vitro cultures, cultured in medium supplemented with 20 % fetal calf serum, were exposed to static magnetic field (SMF) (intensity of 0.6 T) and pulsed electromagnetic fields (PEMF) (21.2 MHz period of 15 ms, burst duration of 2 ms, amplification 3 dBm (0.1 V) and maximum output of 250 W) continually for 72 h. After the exposure, viability was determined using the MTT test and compared with a non-exposed control culture. As compared to the control sample the exposure to SMF resulted in a statistically significant increase (p 0.001) in viability. However, the increase of viability after PEMF exposure was not significant. This could be due to the frequency dependent effect on human cells. The experiment...