Effect of electric field in conditioned aversion response.

The aim of the present study was to estimate whether rat sense exogenous electric field (EF) including one used in our previous studies. Employing a conditioned place aversion response paradigm based on an aversive behavior against light environment, alteration in both voluntary behavior of Wistar rat to a 50 Hz sinusoidal EF was examined. Following conditioning without EF, the times spent in white place in rats was significantly shortened (P<0.05). While, such changes were not shown in rats conditioned with EF. Thus, it was considered that the aversion response to light environment was interfered by exposure to EF. An interference in recognition of brightness via EF induced effect to visual system or in learning system via direct effect to central nerve system was considerable as a factor for EF-induced effect. In addition, it was remained that rat possibly sense exposure to EF as preferable. In order to confirm which factor functioned, further studies are needed.

[Case report of using a connector (phycon TCB bronchial blocker) for pediatric one-lung anesthesia].

We report a case of using a connector (Phycon TCB Bronchial Blocker: Fuji Systems) in pediatric one-lung anesthesia. An eight-year-old boy with mid-mediastinal tumor was scheduled for video-assisted thoracoscopic surgery. After tracheal intubation with normal tracheal tube, we connected the connector and confirmed a 5 Fr Fogarty catheter through the tube under fiberoptic visualization. We were able to achieve one-lung ventilation. The operation was uneventful. This connecter is easy to fix and release the catheter. It is useful to modify the catheter position during one lung ventilation for pediatric patients.

[Anesthetic managements of the patients receiving catheterizable cecostomy].

To improve the quality of life of patients suffering from spinal cord injury, "Catheterizable cecostomy" operation have recently been carried out. In the procedure, cathetelizable stoma is opened and patients are able to control the excretion by injecting enema solution through the stoma. Although operations are usually performed under general anesthesia with tracheal intubation, special considerations sometimes need to be taken for airway management. In such cases, we select spinal anesthesia. Because the surgery is achieved on a fixed charge, efficiency of pre-operative assessment should be done for the cost-cutting with shortening of perioperative period. Diseases including hypertension, diabetes mellitus, etc., must be controlled before admission to the hospital. With these considerations, proper pre-operative assessment can be made.

Effects of exposure to a 50 Hz electric field on plasma levels of lactate, glucose, free Fatty acids, triglycerides and creatine phosphokinase activity in hind-limb ischemic rats.

We previously reported that extremely low frequency electric fields (ELF-EFs) affect energy metabolism in stressed conditions. To further confirm this, the effect of exposure to ELF-EFs on the experimental ischemic rat was examined. The test was based on a comparison of rats treated with EF alone, ischemic surgery alone, the combination of EF with ischemic surgery, or no treatment (double sham). The EF condition used in this study was an alternating current of 50 Hz EF at 17 500 V/m intensity for 15 min per day. The exposure to EF in ischemic rats significantly decreased plasma levels of free fatty acids and triglycerides, compared to those of the no treatment or EF alone group. The plasma lactate levels of two ischemic groups peaked on experimental day-4 and gradually decreased until the end of the study. The changes in the lactate levels induced by ischemia did not show any difference between rats treated with ischemia alone or a combination of ischemia with an EF. Any changes in plasma levels of glucose and creatine phosphokinase activity were not influenced by EF treatment. These results indicate that the EF effect on glycolysis parameters, plasma lactate or glucose levels, does not appear in a highly stressed condition and that EF effects varied dependent on the condition of organism but ELF-EF used in this study have impact on lipid metabolism parameter in a hind-limb ischemic rat. However, further studies are needed to elucidate the association of ELF-EF with the lipid metabolism system.

Prolonged Ca2+ transients in ATP-stimulated endothelial cells exposed to 50 Hz electric fields.

Human umbilical vein endothelial cells were exposed to sinusoidal electric fields of 0.3 or 30 kV/m, 50 Hz, for 24 h. Changes in intracellular calcium concentration ([Ca(2+)](i)) induced by ATP-stimulation in the absence of extracellular Ca(2+) were observed in individual cells. No differences were observed between the exposure and sham-exposure groups in [Ca(2+)](i) resting level before ATP-stimulation, or in the [Ca(2+)](i) peak levels induced by stimulation. However, the duration of the initial transients in [Ca(2+)](i) following an ATP stimulus was significantly prolonged by exposure to a 30 kV/m field. The inositol trisphosphate receptor inhibitor, xestospongin C, inhibited the ATP-induced elevation in [Ca(2+)](i) in both the exposure and sham-exposure groups. The ATP-receptor P2Y appeared to play an important role in the increase of [Ca(2+)](i). The present results suggest that an extremely low-frequency electric field affects the function of vascular endothelial cells by a mechanism involving activation of P2Y.

Effects of a 50 Hz electric field on plasma lipid peroxide level and antioxidant activity in rats.

The effects of exposure to extremely low frequency electric fields (ELF EFs) on plasma lipid peroxide levels and antioxidant activity (AOA) in Sprague-Dawley rats were studied. The test was based on comparisons among rats treated with a combination of the oxidizing agent, 2,2'-azobis(2-aminopropane) dihydrochloride (AAPH) and 50 Hz EF of 17.5 kV/m intensity for 15 min per day for 7 days, AAPH alone, EF alone or no treatment. EF significantly decreased the plasma peroxide level in rats treated with AAPH, similar to treatment by ascorbic acid or the superoxide dismutase. Ascorbic acid increased AOA; however, EF and superoxide dismutase did not change AOA compared with sham exposure in stressed rats. No influence on the lipid peroxide level and AOA in unstressed rats was observed with EF exposure alone. Although the administration of AAPH decreased AOA, this decrease did not change when EF was added. These data indicate that the ELF EF used in this study influenced the lipid peroxide level in an oxidatively stressed rat.