Effects of magnetic fields on many functions of human and other mammalian cells and proposal of guidelines and Standard for Human Health

1. 1.5 T时变磁场暴露对牛肾上腺嗜铬细胞跨膜Ca^2+内流无影响，但强烈抑制多种神经递质诱导的细胞内Ca ^2+库释放Ca^2+。钙库通过兰尼碱受体释放Ca ^2+也受到抑制.强磁场暴露可强烈抑制加入咖啡因或ATP的嗜铬细胞瘤细胞（PC 12细胞）胞内Ca ^2+释放。加入神经生长因子（NGF）诱导PC 12细胞突起生长。在存在NGF的情况下，暴露于极低频（ELF）磁场刺激分化.利用傅里叶变换红外光谱（FT-IR）研究了极低频磁场对HeLa细胞膜结构的影响。该暴露将酰胺I带的峰吸光度移动到较小的波数，降低酰胺II带的峰吸光度，并增加在约1600 cm-2处的吸光度<-1>。这些结果表明，ELF场暴露对肽键的N-H面内弯曲和C-N伸缩振动具有可逆性影响，改变了细胞膜蛋白的α-螺旋和β-折叠的二级结构。我们发现暴露于ELF场的细胞和在酸性介质中孵育的细胞之间的FT-IR光谱发生了类似的变化，但这些变化与在高K^+介质中孵育的细胞不同。

1. Exposure to the time-varying 1.5 T magnetic field did not affect Ca^<2+> influx across plasma membrane of bovine adrenal chromaffin cells, but strongly inhibited Ca^<2+> release from intracellular Ca^<2+> stores induced by addition of variety of neurotransmitters. Ca^<2+> release from Ca^<2+> stores via ryanodine receptor also suppressed by the exposure.2. Exposure to the strong magnetic field strongly suppressed Ca^<2+> release from intracellular Ca^<2+> stores of pheochromocytoma cells (PC12 cells) by addition of caffeine or ATP.3. Addition of nerve growth factor (NGF) induced a neurite outgrowth of PC12 cells. In the presence of NGF, exposure to an extremely low frequency (ELF) magnetic field stimulate the differentiation.4. We measured the effects of ELF magnetic field on membrane structure of HeLa cells studied by Fourier transform infrared (FT-IR) spectroscopy. This exposure shifted the peak absorbance of the amide I band to a smaller wave number, reduced the peak absorbance of the amide II band, and increase absorbance at around 1600 cm^<-1>. These results suggest that the ELF field exposure has reversible effects on the N-H inplane bending and C-N stretching vibrations of peptide linkages, the changes the secondary structures of alpha-helix and beta-sheet in cell membrane proteins. We found similar changes in FT-IR spectra between cells exposed to ELF field and those incubated in an acidic medium, but these changes were different from those incubated in an high K^+ medium.