label: url

en: Reading FCS files and plotting the data using a free ware program

ja: フリーウエアを用いたFCS出力ファイルの読み込みと描画

en: Journal of Medical Technology

ja: 臨床検査


en: Exposure to an Extremely-Low-Frequency Magnetic Field Stimulates Adrenal Steroidogenesis via Inhibition of Phosphodiesterase Activity in a Mouse Adrenal Cell Line

en: Extremely low-frequency magnetic fields (ELF-MFs) are generated by power lines and household electrical devices. In the last several decades, some evidence has shown an association between ELF-MF exposure and depression and/or anxiety in epidemiological and animal studies. The mechanism underlying ELF-MF-induced depression is considered to involve adrenal steroidogenesis, which is triggered by ELF-MF exposure. However, how ELF-MFs stimulate adrenal steroidogenesis is controversial. In the current study, we investigated the effect of ELF-MF exposure on the mouse adrenal cortex-derived Y-1 cell line and the human adrenal cortex-derived H295R cell line to clarify whether the ELF-MF stimulates adrenal steroidogenesis directly. ELF-MF exposure was found to significantly stimulate adrenal steroidogenesis (p < 0.01-0.05) and the expression of adrenal steroid synthetic enzymes (p < 0.05) in Y-1 cells, but the effect was weak in H295R cells. Y-1 cells exposed to an ELF-MF showed significant decreases in phosphodiesterase activity (p < 0.05) and intracellular Ca2+ concentration (p < 0.01) and significant increases in intracellular cyclic adenosine monophosphate (cAMP) concentration (p < 0.001-0.05) and cAMP response element-binding protein phosphorylation (p < 0.05). The increase in cAMP was not inhibited by treatment with NF449, an inhibitor of the Gs alpha subunit of G protein. Our results suggest that ELF-MF exposure stimulates adrenal steroidogenesis via an increase in intracellular cAMP caused by the inhibition of phosphodiesterase activity in Y-1 cells. The same mechanism may trigger the increase in adrenal steroid secretion in mice observed in our previous study.

en: PLoS ONE

ja: PLoS ONE


en: Effects of UV-A LED light irradiation on growth of cultured RAW 264.7 cells

en: Toxicological and Environmental Chemistry


en: Re-design and evaluation of the NMR probes for living organs and tissues

ja: 生体試料用改良型NMRプローブの作製と評価

en: We have constructed NMR signal detectors (probes) to measure the NMR spectra of living organs and tissues kept under physiological conditions. The probes consisted of non-magnetic aluminum alloy cylinder to support the detection coil made of cupper, mounted on a Teflon plate with acrylics plates and rods, however, the recovery time to the static magnetic field after turning off of the pulsed gradient field was more than 10 times longer than that of the micro-MRI probe available commercially. The re-design of our probes, such as acrylics cylinder to support the coil, together with readjustment of the eddy current compensation circuit, provided us the recovery time to the static field less than 1 msec, making it possible to measure the diffusion coefficient of Na+ ion using the pulsed field gradient spin echo method. The diffusion coefficient of Na+ ion in skeletal muscle isolated from bullfrog was 0.6 time larger than that in Ringer's solution, suggesting a high viscosity in the skeletal muscle.

en: Shikoku Acta Medica

ja: 四国医学雑誌


en: Chronic exposure to an extremely low-frequency magnetic field induces depression-like behavior and corticosterone secretion without enhancement of the hypothalamicpituitaryadrenal axis in mice

en: An extremely low-frequency magnetic field (ELF-MF) is generated by power lines and household electrical devices. Many studies have suggested an association between chronic ELF-MF exposure and anxiety and/or depression. The mechanism of these effects is assumed to be a stress response induced by ELF-MF exposure. However, this mechanism remains controversial. In the present study, we investigated whether chronic ELF-MF exposure (intensity, 1.5 mT; [corrected] total exposure, 200 h) affected emotional behavior and corticosterone synthesis in mice. ELF-MF-treated mice showed a significant increase in total immobility time in a forced swim test and showed latency to enter the light box in a light-dark transition test, compared with sham-treated (control) mice. Corticosterone secretion was significantly high in the ELF-MF-exposed mice; however, no changes were observed in the amount of the adrenocorticotropic hormone and the expression of genes related to stress response. Quantification of the mRNA levels of adrenal corticosteroid synthesis enzymes revealed a significant reduction in Cyp17a1 mRNA in the ELF-MF-exposed mice. Our findings suggest the possibility that high intensity and chronic exposure to ELF-MF induces an increase in corticosterone secretion, along with depression- and/or anxiety-like behavior, without enhancement of the hypothalamic-pituitary-adrenal axis.

en: Bioelectromagnetics

ja: Bioelectromagnetics


en: Effects of mechanical pressure on cytoskeleton in human umbilical vein endothelial cells cultured in a newly developed chamber.

ja: 新規開発培養チャンバーを用いた物理的圧迫によるHUVEC細胞骨格への影響


en: Changes in DNA structure in the DPI-induced apoptosis in cultured human HepG2 cells

ja: DPIにより誘導されるヒト培養HepG2細胞死のDNA構造の解明


en: Effects of a 1.5 T time-varying magnetic field on cell volume regulation of bovine adrenal chromaffin cells in hyposmotic media.

en: Effects of a time-varying magnetic field on cell volume regulation by hyposmotic stress in cultured bovine adrenal chromaffin cells were examined. Through regulatory volume decrease (RVD), cell volume of chromaffin cells that were incubated in a hypotonic medium initially increased, reached a peak and finally recovered to the initial value. Two hour exposure to a magnetic field and addition of cytochalasin D increased peak value and delayed return to initial value. Intracellular F-actin contents initially decreased but returned to normal levels after 10 sec. Two hour exposure to the magnetic field and addition of cytochalasin D continuously reduced the F-actin content. Results suggest that exposure to the magnetic field stimulated disruption of the actin cytoskeleton and that the disruption delayed the recovery to the volume prior to osmotic stress.

en: The Journal of Medical Investigation : JMI


en: Feed-forward changes in carotid blood flow velocity during active standing.

en: Orthostatic changes induce temporary loss of circulatory regulation. Feedback systems react to cardiovascular alterations to compensate for the instability. To clarify the existence of anticipatory cardiovascular regulation during active standing, we continuously recorded blood flow velocity (BFV) in the common carotid artery and cerebral blood volume (CBV) in healthy men. The maximum BFV value decreased significantly before standing in the reaction-time condition. The decrease significantly correlated with the change in systolic blood pressure that accompanies upright standing from a supine position. The anticipatory BFV decrease disappeared during self-paced standing, and all BFV parameters significantly declined after the self-paced standing. The CBV recording showed a significant increase in oxyhemoglobin levels before standing in the reaction-time condition. Our study suggests that some feed-forward cardiovascular regulation triggered by central command could be activated before standing, and it may play a functional role in the maintenance of cerebral perfusion during standing.

en: Neuroscience Letters

ja: Neuroscience Letters


en: Effects of ELF magnetic fields on signal transduction in osteoblast-like cells

ja: 培養骨芽細胞のシグナル伝達に及ぼすELF磁界の影響

en: 日本生体磁気学会誌 特別号 第20回日本生体磁気学会論文集

ja: 日本生体磁気学会誌 特別号 第20回日本生体磁気学会論文集


en: Effects of a time-varying strong magnetic field on transient increase in Ca2+ release induced by cytosolic Ca2+ in cultured pheochromocytoma cells

en: Exposure of pheochromocytoma (PC 12) cells to a time-varying 1.51 T magnetic field inhibited an increase in the intracellular Ca2+ concentration ([Ca2+]i) induced by addition of caffeine to Ca(2+)-free medium. This inhibition occurred after a 15-min exposure and was maintained for at least 2 h. [Ca2+]i sharply increased in cells loaded with cyclic ADP-ribose, and 2-h exposure significantly suppressed the increase. Addition of ATP induced a transient increase in intracellular Ca2+ release mediated by IP3 receptor, and this increase was strongly inhibited by the exposure. Results indicated that the magnetic field exposure strongly inhibited Ca2+ release mediated by both IP3 and ryanodine receptors in PC 12 cells. However, thapsigargin-induced Ca2+ influx (capacitative Ca2+ entry) across the cell membrane was unaffected. The ATP content was maintained at the normal level during the 2-h exposure, suggesting that ATP hydrolysis was unchanged. Therefore, Mg2+ which is known to be released by ATP hydrolysis and inhibit intracellular Ca2+ release may not relate the exposure-caused inhibition. Eddy currents induced in culture medium appear to change cell membrane properties and indirectly inhibit Ca2+ release from endoplasmic reticulum and other Ca2+ stores in PC 12 cells.

en: Biochimica et Biophysica Acta (BBA) - General Subjects


en: Effects of Time-Varying Strong Magnetic Fields on Rerease of Cytosolic Free Ca2+ from Intracellular Stores in Cultured Bovine Adrenal Chromaffin Cells

en: This study was made to explain the mechanisms for the effects of exposure to a time varying 1.51 T magnetic field on the intracellular Ca(2+) signaling pathway. The exposure inhibited an increase in intracellular Ca(2+) concentration ([Ca(2+)](i)) in bovine chromaffin cells induced by addition of bradykinin (BK) to a Ca(2+) free medium. The exposure did not change BK induced production of inositol 1,4,5-trisphosphate (IP(3)). [Ca(2+)](i) was markedly increased in IP(3) loaded cells, and this increase was inhibited by the magnetic field exposure. A similar increase in [Ca(2+)](i) by other drugs, which stimulated Ca(2+) release from intracellular Ca(2+) stores, was again inhibited by the same exposure. However, transmembrane Ca(2+) fluxes caused in the presence of thapsigargin were not inhibited by the magnetic field exposure in a Ca(2+) containing medium. Inhibition of the BK induced increase in [Ca(2+)](i) by the exposure for 30 min was mostly recovered 1 h after exposure ended. Our results reveal that the magnetic field exposure inhibits Ca(2+) release from intracellular Ca(2+) stores, but that BK bindings to BK receptors of the cell membrane and intracellular inositol IP(3) production are not influenced.


en: ImSpecter法による培養骨牙細胞に及ぼすELF変動磁界の影響

ja: ImSpecter法による培養骨牙細胞に及ぼすELF変動磁界の影響

en: Technical Report of IEICE, MBE

ja: Technical Report of IEICE, MBE