title: In vivo electron spin resonance analysis of nitroxide radicals injected into a rat by a flexible surface-coil-type resonator as an endoscope- or a stethoscope-like device.
abstract: The flexible surface-coil-type resonator (FSCR) operating in a 700 MHz microwave electron spin resonance (ESR) system was applied to measure the nitroxide radicals at a specific area in rats. The FSCR was composed of a single-turn coil with a diameter of 5 mm and two flexible coaxial lines of 450 mm in length. For an endoscope-like application, the FSCR was inserted into the rectum of the rat and sequential changes in the ESR signals of the intravenously injected nitroxide radical (4-hydroxy-2,2,6,6-tetramethyl-piperidine-1-oxyl; TEMPOL or 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-yloxy; carbamoyl-PROXYL) were measured. The ESR signal intensity of the nitroxide decreased according to first-order kinetics. For a stethoscope-like application, the FSCR was placed at several sites on the abdominal skin of the rats receiving a subcutaneous injection of carbamoyl-PROXYL, and diffusion and/or metabolism of the radical in the skin was observed.
authors.affiliation: Graduate School of Engineering, Yamagata University, Yonezawa, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Lin
authors.forename: H
authors.initials: H
authors.lastname: Yokoyama
authors.forename: S
authors.initials: S
authors.lastname: Ishida
authors.forename: N
authors.initials: N
authors.lastname: Tsuchihashi
authors.forename: T
authors.initials: T
authors.lastname: Ogata
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000378:metabolism / Q000493:pharmacokinetics; D003497:Cyclic N-Oxides / Q000008:administration & dosage / Q000378:metabolism / Q000493:pharmacokinetics; D004578:Electron Spin Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*; D005609:Free Radicals; D008297:Male; D009569:Nitric Oxide / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D011759:Pyrrolidines / Q000008:administration & dosage / Q000378:metabolism / Q000493:pharmacokinetics; D011837:Radiation-Protective Agents / Q000008:administration & dosage / Q000378:metabolism / Q000493:pharmacokinetics; D051381:Rats; D017208:Rats, Wistar; D012867:Skin / Q000378:metabolism; D013113:Spin Labels
chemical_list: D000975:Antioxidants; D003497:Cyclic N-Oxides; D005609:Free Radicals; D011759:Pyrrolidines; D011837:Radiation-Protective Agents; D013113:Spin Labels; D009569:Nitric Oxide; C077426:3-carbamoyl-2,2,5,5-tetramethyl-1-pyrrolidinyl-N-oxyl; C001803:tempol