title: Dissociation of neopterin and 7,8-dihydroneopterin from plasma components before HPLC analysis.
abstract: Measurement of plasma neopterin by HPLC with fluorescence detection is used clinically as a marker of immune cell activation in the management of a number of disease pathologies. HPLC analysis of neopterin requires the acidic removal of plasma proteins but we have found that 7,8-dihydroneopterin is oxidised to neopterin with varying yield. Using acetonitrile as the precipitant, we have measured substantially higher quantities of both total neopterin (7,8-dihydroneopterin and neopterin) and neopterin from plasma of healthy and septicemia patient's. Total neopterin concentrations were on average 50% and 200% greater in healthy and septicemia subjects, respectively, when measured after acetonitrile precipitation compared to trichloroacetic acid. Our data suggests that some pterin co-precipitates with proteins during acid treatment.
authors.affiliation: Free Radical Biochemistry Laboratory, University of Canterbury, Christchurch, New Zealand.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Flavall
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Crone
authors.forename: Grant A
authors.initials: GA
authors.lastname: Moore
authors.forename: Steven P
authors.initials: SP
authors.lastname: Gieseg
mesh_terms: D015415:Biomarkers / Q000097:blood; D001798:Blood Proteins / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007202:Indicators and Reagents; D019798:Neopterin / Q000031:analogs & derivatives* / Q000097:blood / Q000528:radiation effects; D010084:Oxidation-Reduction; D015203:Reproducibility of Results; D018805:Sepsis / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D015415:Biomarkers; D001798:Blood Proteins; D007202:Indicators and Reagents; C000976:7,8-dihydroneopterin; D019798:Neopterin