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Possible Health Effects of Exposure to Residential Electric and Magnetic Fields
Calcium ions (Ca2+) either occur inside a hydration shell or are bound to a protein, producing a charged spatial oscillator. In the model, either of those states resonantly absorb energy from the appropriate alternating fields and are spiraled into or out of the cell through the protein channels in the membrane. Although a charged ion of the mass of calcium has a resonance at nearly 60 Hz in the earth's static magnetic field, such a resonance can only be observed if the state decays through an electromagnetic transition. Lednev's calculations neglected the effects of collision damping of the states (Adair 1992) and have been shown to violate the laws of physics (Halle 1988). Therefore, whether or not 60-Hz EMF cause changes in calcium concentrations, the ICR model, as currently set forth, is not a viable mechanism for biologic systems.
Even though the ICR mechanism is not viable, a number of experiments have been performed at charge-to-mass ratios (q:m) corresponding to the calculated ICR frequency for calcium (e.g., see Parkinson and Hanks 1989a; Walleczek and Budinger 1992; Yost and Liburdy 1992). One such set of resonant conditions occurs at a frequency of 16 Hz and a dc magnetic field (B) of 23.4 µT (234 mG) according to the relationship frequency (Hz = 1/2t(q/m)Bdc).
The results are conflicting. Parkinson and Hanks (1989a) see no effect on changes in cytosolic calcium concentrations (sweeping through both resonant and nonresonant EMF conditions) for BALB/c3T3, L929, V-79, and ROS cells, but other investigators (Liburdy 1992b; Walleczek and Budinger 1992; Yost and Liburdy 1992) see changes when the low-frequency magnetic-field challenge is combined with a mitogen.
Cytosolic Calcium Oscillators It is well established that the intracellular calcium concentration can display an oscillatory behavior in response to an external stimulus (Fewtrell 1993; Meyer and Stryer 1991, and references cited therein). The period of these oscillations is typically between 1 sec and several minutes. Recently, a model based on nonlinear dynamics and on the theory of self-sustained (limit-cycle) oscillators was developed that shows how a small modulation of the signal pathway at an early stage can lead to large changes in calcium metabolism of the cell (Eichwald and Kaiser 1993). These assertions have not yet been tested by experiment.
Relationship Between Very-Low-Frequency Electric and Magnetic Fieldsand Bone-Healing Protocols for Osteogenesis The efficacy of exposures to electric and magnetic fields in bone healing has been observed (Falugi et al. 1987; Bassett 1990), at least when applied directly to the bone. Typical bone-healing protocols have involved pulsed 20-µsec magnetic fields. The magnetic-field strength used varies from 0 to 2,000 µT (Falugi et al. 1987). One of the mechanisms attributed to the effect of magnetic fields is that the ions in the medium between the bone ends are moved back and forth by the ac field. Ions trapped by the bone matrix become bound to the matrix, thus reducing the concentration of free ions in the