50 Hz magnetic field exposure alters onset of S-phase in normal human fibroblasts

Abstract

This study was undertaken to investigate whether power frequency magnetic fields can affect the kinetics of cell cycle progression in exposed human cells. To achieve this, cultures of normal human fibroblasts were synchronised in the G0 phase of the cell cycle and exposed to 50 Hz magnetic fields at a range of flux densities. Progression through the cycle was monitored by examining the timing of entry into S phase, as characterised by the onset of DNA synthesis. Simultaneous positive controls were exposed to human recombinant fibroblast growth factor to demonstrate that the system was responsive to external stimuli. Exposure to magnetic fields at 20 and 200 μT induced a small but significant increase in the length of the G1 phase of the cell cycle. However, exposure at higher flux densities of 2 and 20 mT had no significant effect. These results are discussed in relation to weak magnetic field effects on free radical concentration. Bioelectromagnetics 20:446–452, 1999. Published 1999 Wiley‐Liss, Inc.

No influence of magnetic fields on cell cycle progression using conditions relevant for patients during MRI

“…Small variations in cell cycle distribution during postexposure incubation were reported in the latter study. Similarly, an influence on cell cycle progression by 2 T (84 ms), 3.4-8.8 mT (60 Hz), 6.34 T (static), 20 and 200 mT (50 Hz), 5 mT (static), as well as 1.5 mT (50, 60, and 75 Hz) was reported by Clejan et al [1996], Levin and Ernst [1995], Zhang et al [1995], Cridland et al [1999], and Rapley et al [1998], respectively.…”

“…However, a similar number of studies has been published that did not observe an influence of MFs on cell cycle progression [Raylmann et al, 1996;Reipert et al, 1996;Nafziger et al, 1997;Sakurai et al, 1999;Wiskirchen et al, 1999Wiskirchen et al, , 2000Loberg et al, 2000;Rodegerts et al, 2000;Mangiacasale et al, 2001]. In these studies different cell types were exposed to static [Raylmann et al, 1996;Sakurai et al, 1999;Wiskirchen et al, 1999Wiskirchen et al, , 2000 as well as ELFMGFs [Reipert et al, 1996;Nafziger et al, 1997;Cridland et al, 1999;Loberg et al, 2000;Rodegerts et al, 2000;Mangiacasale et al, 2001]. The mentioned studies demonstrate how difficult it is to obtain clear information from the literature about whether MFs influence cell cycle progression or not.…”

“…To our knowledge at least 19 publications have reported about this topic since 1995. Ten of them showed a positive influence on cell cycle progression [Liboff et al, 1984;Levin and Ernst, 1995;Zhang et al, 1995;Clejan et al, 1996;Eremenko et al, 1997;Schimmelpfeng and Dertinger, 1997;Rapley et al, 1998;Cridland et al, 1999;Buemi et al, 2001;Markkanen et al, 2001], whereas nine were negative [Raylmann et al, 1996;Reipert et al, 1996;Nafziger et al, 1997;Sakurai et al, 1999;Wiskirchen et al, 1999Wiskirchen et al, , 2000Loberg et al, 2000;Rodegerts et al, 2000;Mangiacasale et al, 2001]. The difference (negative vs. positive) is most probably due to different exposure conditions and different experimental controls.…”

Effect of extremely low frequency magnetic fields on cell proliferation and gene expression

“…We observed delayed cell cycle progression due to ELF-MF exposure at 1 mT of flux intensity, but not at 0.1 or 0.5 mT in both MCF7 and MCF10A cell lines, suggesting there is an intensity threshold of ELF-MF to affect biological processes. Cridland et al [1999] demonstrated that whereas exposure to 20 and 200 mT induced a small but significant increase in cell cycle delay, exposure at 2 and 20 mT had no significant effect on normal human fibroblasts. The authors discussed effects of weak magnetic fields on free radical concentration.…”

Effects of 50 Hz magnetic field on cell cycle kinetics and the colony forming ability of budding yeast exposed to ultraviolet radiation

“…The possible effect of MF on cell cycle kinetics was seen only at one time point. Cridland et al [1999] recently reported a small but significant increase in the length of the G 1 phase of cell cycle in MF exposed normal human fibroblasts when flux densities of 20 and 200 mT were used.…”