title: Negative chemical ionization gas chromatography/mass spectrometry to quantify urinary 3-methylhistidine: application to burn injury.
abstract: A rapid method for measuring 3-methylhistidine (3MH) in rat and human urine with higher sensitivity and precision than any previously reported method is described using internal standard [1-(13)C]3MH (M+1) and negative chemical ionization (NCI) gas chromatography/mass spectrometry (GC/MS). Internal standard [1-(13)C]3MH (M+1) was added to rat and human urine samples, hydrolyzed, and absorbed onto cation exchange columns. The column eluent was dried and derivatized for GC/MS analysis. Quantification of 3MH levels was accomplished by monitoring the m/z 204 fragment. The m/z 204 fragment was chosen due to the fragment's abundance and stability as determined by analysis of [methyl-(2)H(3), (18)O(2)]3MH (M+7) and [methyl-(13)C]3MH (M+1) fragmentation patterns under NCI conditions. This method shows excellent linearity (0.9989) over the range studied (0-0.5 mol), high recovery (95.9%), and low coefficient of variation (4.7%). The described method is sensitive enough to detect 6.8 pmol amount of urinary 3MH with a precision of 9.1%. The in vivo utility of this method to quantify urinary 3MH was tested in a burn injury rat model and on urine specimens from pediatric burn patients. Data obtained from the urine of burn-injured rats and pediatric burn patients match previously reported trends and validate the in vivo utility of this method.
authors.affiliation: Shriners Burns Hospital, Boston, MA 02114, USA. dbeffa@uic.edu
authors.forename: David C
authors.initials: DC
authors.lastname: Beffa
authors.forename: Edward A
authors.initials: EA
authors.lastname: Carter
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Lu
authors.forename: Yong-Ming
authors.initials: YM
authors.lastname: Yu
authors.forename: Kathrina
authors.initials: K
authors.lastname: Prelack
authors.forename: Robert L
authors.initials: RL
authors.lastname: Sheridan
authors.forename: Vernon R
authors.initials: VR
authors.lastname: Young
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Fischman
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Tompkins
mesh_terms: D000293:Adolescent; D000818:Animals; D002056:Burns / Q000652:urine*; D002648:Child; D002675:Child, Preschool; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D007223:Infant; D008762:Methylhistidines / Q000592:standards / Q000652:urine*; D015394:Molecular Structure; D051381:Rats; D012015:Reference Standards; D015203:Reproducibility of Results
chemical_list: D008762:Methylhistidines