Response of cytosolic calcium, cyclic AMP, and cyclic GMP in Dimethylsulfoxide-differentiated HL-60 cells to modulated low frequency electric currents

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The influence of interferential current (IFC) on the release of four cytokines was investigated. IFC is an amplitude‐modulated 4 kHz current used in therapeutic applications. Human promyelocytes (HL‐60) were differenti ated to monocytes/macrophages by treatment with calcitriol. Release of tumor necrosis factor α (TNFα) and interleukines 1β, 6, and 8 (IL‐1β, IL‐6, and IL‐8) into the supernatant was measured after exposure to IFC at different modulation frequencies. TNFα release was stimulated about twofold by 4 kHz sine waves alone. The influences of exposure time (5–30 min) and current density (2.5–2500 μA/c m2) were tested. A maximum field effect was found at an exposure time of 15 min and a current density of 250 μA/cm2. With these exposure conditions (15 min and 250 μA/cm2 ), cells were treated at different modulation frequencies and reacted for TNFα, IL‐1β, and IL‐8 release in a complex manner. Within the frequencies studied (0–125 Hz), we found stimulation as well as depression of the release. In a second run the cells were activated by pretreatment with 10 μg/ml lipopolysaccharide (LPS) and exposed in the same way as the nonactivated cells. Again the modulation frequency influenced, in a complex way, the induction of TNFα, IL‐1β, and IL‐8, resulting in a pattern of stimulation and depression of release different from that found in nonactivated cells. For IL‐6 production no significant changes were detected in activated or non‐activated cells. Bioelectromagnetics 21:238–244, 2000. © 2000 Wiley‐Liss, Inc.

Modulation of cytokine production by interferential current in differentiated HL-60 cells

Sontag

2000

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Effects of ELF magnetic field on membrane protein structure of living HeLa cells studied by Fourier transform infrared spectroscopy

Ikehara

Yamaguchi

Hosokawa

et al. 2003

The effects of exposure to a 50 Hz magnetic field (maximum of 41.7 to 43.6 mT) on the membrane protein structures of living HeLa cells were studied using attenuated total reflection infrared spectroscopy. One min of such exposure shifted peak absorbance of the amide I band to a smaller wave number, reduced peak absorbance of the amide II band, and increased absorbance at around 1600 cm(-1). These results suggest that exposure to the ELF magnetic field has reversible effects on the N-H inplane bending and C-N stretching vibrations of peptide linkages, and changes the secondary structures of alpha-helix and beta-sheet in cell membrane proteins.

Response of cyclic AMP by DMSO differentiated HL‐60 cells exposed to electric interferential current after prestimulation

Sontag¹

2004

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The action of interferential current (IFC) upon intracellular content of cyclic adenosine monophosphate (cAMP) after prestimulation with the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (fMLP) has been investigated. Human promyelocytes (HL-60) differentiated to granulocytes by dimethylsulphoxide (DMSO) have been treated with different concentrations of fMLP. This enhances their cAMP content. The half maximal effective concentration (EC50) was about 4 nM. Exposure to IFC with modulation frequencies of 35 and 125 Hz (5 min, 250 microA/cm2) after prestimulation with various concentrations of fMLP had no enhancing effect at low or high concentrations of fMLP. In contrast, at medium concentrations in the range of about 100 pM fMLP, a significant enhancement of cAMP could be observed. This synergistic effect of fMLP and IFC has been examined in detail by varying the modulation frequency, current density, and exposure time. Enhancement of cAMP content could be observed at certain modulation frequencies and exposure times suggesting a window effect, whereas for the current density in the range measured (8.5 microA/cm2-2.5 mA/cm2) a constant enhancement could be observed. The synergistic effect of fMLP and IFC could only be observed in the treatment sequence of fMLP followed by IFC; an inverse sequence had no effect on the cAMP content. .