健康科学研究所::Toshitaka Ikehara

Toshitaka Ikehara

2017/03/23
Division of Life Style Disease
Main Research Areas
1.Effects of ultraviolet and visible light irradiation on human body
We have been investigating the influence of ultraviolet (UV), visible, and infrared light on cultured immunological and epithelial cell lines, for examples, RAW 264.7, HeLa S3 cells etc. by using LED (light emitting diode). Specially, we are interested in the effects of reactive oxygen species (ROS) induced by UVA irradiation on the fundamental and special physiology functions, for examples, cell growth, intracellular signal transduction, neurotransmitter secretion etc.. . We also try to test the influences of these varied light irradiations by LED on many physiological functions of cultured cells.

2. Periodontitis with bone resorption is caused by inflammatory reactions to bacterial infection. We reported that electromagnetic wave irradiation (EMWI) has bactericidal effects. However, the effects of the EMWI on periodontal tissues remain unclear. Now, we have been trying to investigate the effects of the electromagnetic irradiation.

3.Effects of high frequency magnetic field on human body
We have studied on the influence of high frequency electromagnetic field (HFMF) exposure on nerve like cells, such as an adrenal chromaffin cells. We measured a transient increase in intracellular Ca2+ concentration in HFMF exposed cells, but the statistical significant difference is not accepted. The magnetic field of this level occurs from several cooking devices already used at home. Then, now we are investigating the influences of the high frequency electromagnetic field exposure on other physiological functions of several cultured cells.

4.Effects of an extremely low frequency (ELF) magnetic field on human body
We have been studying influences of an extremely low frequency electromagnetic field (1/6-Hz, 1.5T) exposure to cultured adrenal chromaffin cells, and. have shown the magnetic field effects on the acetylcholine-induced transient increase in intracellular Ca2+ concentration, morphology of intracellular actin filaments, mitochondrial membrane potential, and oxygen uptake into the cells. But, we haven’t clarified effects of the ELF magnetic field on cellular physiological function yet. In this experiment, we try to verify about these magnetic field effects.


Selected Papers
1. Ikehara T., Nakahashi M., Zehong S., Akutagawa, M., Tsuchiya K., Kitamura M., Takahashi A., Kinouchi Y. Effects of UV-A LED light irradiation on growth of cultured RAW cells. Toxicol. Environ. Chem., 97(2), 243-255, 2015.
2. Ikehara, T., Nishisako, H., Minami, Y., Ichinose(Sasaki), H., Shiraishi, T., Kitamura, M., Shono, M., Houchi, H., Kawazoe, K., Minakuchi, K., Yoshizaki, K. Kinouchi, Y. Miyamoto, H. Effects of exposure to a time-varying 1.5 T magnetic field on neurotransmitter-activated increase in intracellular Ca2+ in relation to actin fiber and mitochondrial functions in bovine adrenal chromaffin cells. Biochimica et Biophysica Acta, 1800(12) 1221- 123, 2010
3. Hamamoto, A. Mori, M., Takahashi, A., Nakano, M., Wakikawa, N., Akutagawa, M., Ikehara, T., Nakaya, Y., Kinouchi, Y. New water disinfection system using UVA light-emitting diodes. J Applied Microbiology, 103(6) 2291- 2298, 2007
4. Ikehara, T., Yamaguchi, H., Hosokawa, K., Houchi, H., Park, K. H., Minakuchi, K., Kashimoto, H., Kitamura, M.., Kinouchi, Y., Yoshizaki, K., Miyamoto, H. Effects of a time-varying magnetic field on transient increase in Ca2+ release induced by sytosolic Ca2+ in cultured pheochromocytoma cells. Biochimica et Biphysica Acta, 1724(1,2) 8~16, 2005
5. Ikehara, T., Yamaguchi, H., Hosokawa, K., Miyamoto, H., Aizawa. K. Effects of ELF magnetic field on membrane protein structure of living HeLa cells studied by fourier transform infrared spectroscopy. Bioelectromagnetics. 24(7) 457-464, 2003
6. Ikehara, T., Park, K.H., Yamaguchi, H., Hosokawa, K., Houchi, H., Azuma, M., Minakuchi, K., Kashimoto, H., Kitamura, M., Kinouchi, Y., Yoshizaki, K., Miyamoto, H. Effects of a time-varying strong magnetic field on transient increase in cytosolic Free Ca2+ induced by inositol 1,4,5-trisphosphate in cultured bovine adrenal chromaffin Cells. Bioelectromagnetics,23(7) 505-515, 2002
7. Ikehara, T., Park, K.H., Yamaguchi, H., Hosokawa, K., Yoshizaki, K., Miyamoto, H., Aizawa, K., Kinouchi, Y. Effects on Rb+(K+) uptake of HeLa cells in a high K+ medium of exposure to a switched 1.7 Tesla magnetic field. Bioelectromagnetics, 21(3) 228-237, 2000.
8. Ikehara, T., Park, K. H., Houchi, H., Yamaguch, H., Hosokawa, K., Shono, M., Minakuchi, K. Tamaki, T., Kinouchi, Y., Yoshizaki, K., Miyamoto, H. Effects of a time-varying strong magnetic field on transient increase in cytosolic free Ca2+ induced by bradykinin in cultured bovine adrenal chromaffin cells. FEBS Letters, 435(2-3) 229-232,1998
9. Ikehara, T., Yamaguchi, H., Hosokawa, K., Takahashi, A., Miyamoto, H. Kinetic study on the effects of intracellular K+ and Na+ on Na+, K+, Cl- cotransport of HeLa cells by Rb+ influx determination. Journal of Membrane Biology, 132(2) 115-124, 1993
10. Ikehara, T., Takahashi, A.. Yamaguchi, H., Hosokawa, K. , Masuya, T., Miyamoto, H. Regulatory changes in the K+, Cl- and water contents of HeLa cells incubated in an isosmotic high K+-medium. Biochimica et Biophysica.Acta, 1068(1), 115-124, 1993
11. Ikehara, T., Yamaguchi, H., Hosokawa, K., Takahashi, A., Masuya, T., Miyamoto, H. Different patterns of cell volume regulation in hyposmotic media between attached and suspended HeLa cells. Biochimica et Biophysica Acta, 1111(2) 151-158, 1992
12. Ikehara, T., Yamaguchi, H., Hosokawa, K., Miyamoto, H. Kinetic mechanism of ATP action in Na+-K+-Cl-- cotransport of HeLa cells determined by Rb+ influx studies. American Journal of Physiology, 258(4 Pt-1) 599-609, 1990
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