title: Inflammatory sites as a source of plasma neopterin: measurement of high levels of neopterin and markers of oxidative stress in pus drained from human abscesses.
abstract: OBJECTIVE
  Plasma neopterin is a clinical marker of inflammation. Interferon-gamma triggers 7,8-dihydroneopterin and its oxidation product, neopterin, to be released from macrophages. 7,8-dihydroneopterin is a potent antioxidant which can protect macrophages from oxidative damage in vitro. This study examined whether 7,8-dihydroneopterin/neopterin levels reach sufficient concentrations in human pus to provide antioxidant activity and be the source of plasma neopterin.
  
  
  METHODS
  Pus was removed by needle aspiration from 19 patients and examined for total neopterin, protein-bound DOPA, dityrosine, alpha-tocopherol, lipid oxidation and protein carbonyls.
  
  
  RESULTS
  Total neopterin was detected between 50 nM and 1.2 microM, with an average concentration of 0.51 microM. Significant quantities of oxidized proteins and lipids were detected. alpha-Tocopherol concentrations positively correlate with total neopterin levels.
  
  
  CONCLUSIONS
  Total neopterin levels found in the pus was up to 100 times higher than that reported in plasma, suggesting plasma neopterin originates from inflammatory sites. The concentration of total neopterin suggests that 7,8-dihydroneopterin could act as an antioxidant during inflammation.
authors.affiliation: Free Radical Biochemistry Laboratory, School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
authors.forename: Carole A
authors.initials: CA
authors.lastname: Firth
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Laing
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Baird
authors.forename: Joseph
authors.initials: J
authors.lastname: Pearson
authors.forename: Steven P
authors.initials: SP
authors.lastname: Gieseg
mesh_terms: D000038:Abscess / Q000378:metabolism*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004295:Dihydroxyphenylalanine / Q000032:analysis; D005260:Female; D006801:Humans; D007249:Inflammation / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D019798:Neopterin / Q000031:analogs & derivatives / Q000032:analysis / Q000097:blood*; D018384:Oxidative Stress; D013492:Suppuration / Q000378:metabolism*; D014443:Tyrosine / Q000031:analogs & derivatives / Q000032:analysis; D024502:alpha-Tocopherol / Q000032:analysis
chemical_list: C000976:7,8-dihydroneopterin; D014443:Tyrosine; D004295:Dihydroxyphenylalanine; D019798:Neopterin; C007543:dityrosine; D024502:alpha-Tocopherol