@misc{oai:repo.qst.go.jp:00071065, author = {Ueno, Megumi and Nyuui, Minako and Nakanishi, Ikuo and Anzai, Kazunori and Ozawa, Toshihiko and Matsumoto, Kenichiro and Uto, Yoshihiro and 上野 恵美 and 乳井 美奈子 and 中西 郁夫 and 松本 謙一郎}, month = {Mar}, note = {The hyperthermia-induced reactive oxygen species (ROS) scavenging ability of rat plasma was tested. The glutathione (GSH) dependent reduction of a nitroxyl radical, 4-hydroxyl-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPOL), was accelerated temperature dependently. This GSH dependent reduction of TEMPOL can be restricted by adding superoxide dismutase (SOD) or by deoxygenating the reaction mixture, therefore; can be an index of superoxide generation. A reaction mixture containing 0.1 mM TEMPOL and 1 mM GSH was prepared using 100 mM phosphate buffer (PB) containing 0.05 mM diethylenetriaminepentaacetic acid (DTPA). The reaction mixture was kept in a screw-top vial, and was incubated in a water bath at 37 or 44 degrees. The time course of the EPR signal of TEMPOL in the reaction mixture was measured by an X-band EPR spectrometer (JEOL, Tokyo, Japan). The same experiment was done using rat plasma instead of 100 mM PB. The generation of superoxide, i.e. GSH-dependent reduction of TEMPOL, could not be obtained in rat blood plasma, although the first order decay like reduction of TEMPOL could be obtained. Adding 0.5% albumin to the PB reaction mixture could almost cancel the superoxide generation at 37 degrees; however, 0.5% albumin could not cancel the superoxide at 44 degrees, i.e. hyperthermal temperature. Ascorbic acid also showed cancelation of superoxide by 0.01 mM at 37 degrees, however, 0.02 mM or more could cancel superoxide at 44 degrees. Higher concentration of ascorbic acid showed first order reduction, i.e. direct one-electron reduction, of TEMPOL. Hyperthermia induced superoxide in rat plasma can be mostly canceled by relatively high concentration of albumin and ascorbic acid in the plasma., International Free Radical Winter School in Muikamachi 2013}, title = {Cancelation of Hyperthermal Superoxide in Rat Plasma}, year = {2013} }