Empirical test of an ion parametric resonance model for magnetic field interactions with PC‐12 cells

Abstract

A companion paper describes a predictive ion parametric resonance (IPR) model of magnetic field interactions with biological systems based on a selective relation between the ratio of the flux density of the static magnetic field to the AC magnetic field and the charge-to-mass ratio of ions of biological relevance. Previous studies demonstrated that nerve growth factor (NGF)-stimulated neurite outgrowth (NO) in PC-12 cells can be inhibited by exposure to magnetic fields as a function of either magnetic field flux density or AC magnetic field frequency. The present work examines whether the PC-12 cell response to magnetic fields is consistent with the quasi-periodic, resonance-based predictions of the IPR model. We tested changes in each of the experimentally controllable variables [flux densities of the parallel components of the AC magnetic field (Bac) and the static magnetic field (Bdc) and the frequency of the AC magnetic field] over a range of exposure conditions sufficient to determine whether the IPR model is applicable. A multiple-coil exposure system independently controlled each of these critical quantities. The perpendicular static magnetic field was controlled to less than 2 mG for all tests. The first set of tests examined the NO response in cells exposed to 45 Hz Bac from 77 to 468 mG(rms) at a Bdc of 366 mG. Next, we examined an off-resonance condition using 20 mG Bdc with a 45 Hz AC field across a range of Bac between 7.9 and 21 mG(rms). Finally, we changed the AC frequency to 25 Hz, with a corresponding change in Bdc to 203 mG (to tune for the same set of ions as in the first test) and a Bac range from 78 to 181 mG(rms). In all cases the observed responses were consistent with predictions of the IPR model. These experimental results are the first to support in detail the validity of the fundamental relationships embodied in the IPR model.

915 MHz microwaves and 50 Hz magnetic field affect chromatin conformation and 53BP1 foci in human lymphocytes from hypersensitive and healthy persons

“…It has been found by Blackman et al [1985] that the ambient static magnetic fields (SMF) can significantly influence the effects of ELF fields. The importance of SMF for the ELF effects has been confirmed in several studies [Lednev, 1991;Belyaev et al, 1994;Blackman et al, 1994;Fitzsimmons et al, 1994;Prato et al, 1995]. Therefore, the effects of weak ELF are usually observed only under specific combinations of frequency, amplitude, and SMF.…”

“…The ELF effects are also dependent on variety of physical and biological parameters Blackman et al, 1988Blackman et al, , 1994Belyaev et al, 1994Belyaev et al, , 1999aPrato et al, 1995]. Moreover, exposure of human lymphocytes or V79 SPD8 cells to magnetic field at 8 Hz (21 mT rms) resulted in DNA fragmentation [Belyaev et al, 2001c;Olsson et al, 2001].…”

“…The effects of ELF fields have been observed within relatively narrow ''frequency windows'' Blackman et al, 1988Blackman et al, , 1994Belyaev et al, 1994;Prato et al, 1995] and ''amplitude windows'' [Blackman et al, 1982[Blackman et al, , 1994Liboff et al, 1987;Lednev, 1991;Prato et al, 1995]. It has been found by Blackman et al [1985] that the ambient static magnetic fields (SMF) can significantly influence the effects of ELF fields.…”

Effect of electromagnetic field exposure on chemically induced differentiation of friend erythroleukemia cells.

“…Also, their ELF-EMF coils were placed at the top and bottom, whereas ours were placed on each side of the growth chambers. This could also be a potential explanation of the differences because Blackman et al (34)(35)(36) demonstrated that ELF-EMF perpendicular to the static fields of the earth had the greatest effect on Table 2. NEL, no effect level.…”

Brief exposure to a 50 Hz, 100 μT magnetic field: Effects on reaction time, accuracy, and recognition memory

“…Despite several decades of investigation, controversy still surrounds the issue of whether these ELF MFs can cause measurable changes in biological systems and whether these changes are harmful. Nonetheless, a large number of studies, both in vitro and in vivo, strongly suggest that changes can occur, even though the mechanism of interaction remains obscure [Polk, 1991;Blackman et al, 1994;Graham et al, 1996;Beale et al, 1997;National Research Council, 1997].…”