title: Measurement of L-[methyl-11C]methionine in human plasma.
abstract: The routine measurement of L-[methyl-11C]methionine in human plasma after i.v. injection of the tracer is described. The protein-free plasma metabolites of the tracer were analyzed using a cation-exchange column (Aminex A-6) eluted with a pH 4.25 citrate buffer. The ratios of L-[methyl-11C]methionine for the total radioactivity decreased gradually, and the standard deviations among 19 humans were relatively small for 30 min: 97.2 +/- 1.4%, 5 min; 92.6 +/- 2.1%, 10 min; 89.4 +/- 4.0%, 15 min; 84.1 +/- 3.1%, 20 min; 73.1 +/- 9.8%, 30 min; 45.0 +/- 16.8%, 60 min. A convenient analysis using a Bond elute SCX cartridge showed slightly larger ratios than those measured by liquid chromatography.
authors.affiliation: Division of Radiopharmaceutical Chemistry, Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ishiwata
authors.forename: M
authors.initials: M
authors.lastname: Kameyama
authors.forename: J
authors.initials: J
authors.lastname: Hatazawa
authors.forename: K
authors.initials: K
authors.lastname: Kubota
authors.forename: T
authors.initials: T
authors.lastname: Ido
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002250:Carbon Radioisotopes; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D008297:Male; D008715:Methionine / Q000031:analogs & derivatives* / Q000097:blood; D008875:Middle Aged; D014055:Tomography, Emission-Computed
chemical_list: D002250:Carbon Radioisotopes; D008715:Methionine; C038344:methionine methyl ester