title: Determination of plasma Ntau-methylhistamine in vivo by isotope dilution using benchtop gas chromatography-mass spectrometry.
abstract: A practical sensitive and specific method for determination of the stable metabolite of histamine, Ntau-methylhistamine, in human plasma using benchtop gas chromatography-stable isotope dilution mass spectrometry has been developed. Ntau-Methylhistamine, a principal metabolite of histamine in humans, was extracted and purified from human plasma using a two-step procedure with Sep-Pak silica cartridges. Quantitation of Ntau-methylhistamine was made possible by the synthesis of Ntau-[2H3]methylhistamine used as an internal standard. Derivatization with pentafluoropropionyl anhydride of extracts of human plasma yielded the bis-pentafluoropropionyl derivative of Ntau-methylhistamine for measurement using selected ion monitoring of the m/z 417/420 ion pair after electron impact on a benchtop gas chromatography-mass spectrometry (GC-MS). By improvements in the plasma extraction technique, inclusion of a synthetic internal standard and the development of a sensitive and stable derivative of the histamine metabolite, Ntau-methylhistamine was found to be significantly elevated in the plasma of patients with the dermal fibroproliferative disorder, hypertrophic scarring as compared to age-matched normal volunteers (98.5+/-29.5 pg/ml, n=9, versus 43.3+/-16.5 pg/ml, n=8, p<0.05). As such, this method affords a sensitive, specific and practical approach to measurement of histamine metabolites in plasma and other biological fluids.
authors.affiliation: Department of Surgery, University of Alberta, Edmonton, Canada.
authors.forename: E E
authors.initials: EE
authors.lastname: Tredget
authors.forename: T
authors.initials: T
authors.lastname: Iwashina
authors.forename: P G
authors.initials: PG
authors.lastname: Scott
authors.forename: A
authors.initials: A
authors.lastname: Ghahary
mesh_terms: D002056:Burns / Q000097:blood / Q000150:complications; D017439:Cicatrix, Hypertrophic / Q000097:blood / Q000150:complications; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008761:Methylhistamines / Q000097:blood*; D011537:Pruritus / Q000097:blood / Q000209:etiology; D011865:Radioisotope Dilution Technique; D012680:Sensitivity and Specificity
chemical_list: D008761:Methylhistamines; C031205:3-methylhistamine