title: Low plasma protein nitrotyrosine levels distinguish primary Raynaud's phenomenon from scleroderma.
abstract: OBJECTIVE
  To investigate the hypothesis that increased formation of reactive nitrogen species may contribute to the vascular pathology that develops in patients with connective tissue disease such as scleroderma.
  
  
  METHODS
  The level of protein-bound nitrotyrosine in plasma was measured by stable isotope dilution gas chromatography/negative ion chemical ionisation mass spectrometry in 11 patients with primary Raynaud's phenomenon, 37 with scleroderma, 13 with chronic renal impairment, and in 23 healthy controls.
  
  
  RESULTS
  Plasma protein-bound nitrotyrosine was markedly decreased in patients with primary Raynaud's phenomenon (mean (SEM) 0.60 (0.06) ng/mg dry protein) compared with patients with scleroderma (1.78 (0.21) ng/mg protein), chronic renal impairment (1.42 (0.17) ng/mg protein) or healthy controls (1.63+/-0.15 ng/mg protein, ANOVA p<0.001).
  
  
  CONCLUSIONS
  These data suggest that there is decreased nitration of plasma proteins, or increased degradation of nitrated proteins from the circulation of patients with primary but not secondary Raynaud's phenomenon.
authors.affiliation: Royal Free and University College Medical School, University College London (UCL), Rowland Hill Street, London NW3 2PF, UK.
authors.forename: E J
authors.initials: EJ
authors.lastname: Kingdon
authors.forename: A R
authors.initials: AR
authors.lastname: Mani
authors.forename: M T
authors.initials: MT
authors.lastname: Frost
authors.forename: C P
authors.initials: CP
authors.lastname: Denton
authors.forename: S H
authors.initials: SH
authors.lastname: Powis
authors.forename: C M
authors.initials: CM
authors.lastname: Black
authors.forename: K P
authors.initials: KP
authors.lastname: Moore
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D001798:Blood Proteins / Q000737:chemistry*; D002849:Chromatography, Gas; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011928:Raynaud Disease / Q000097:blood / Q000175:diagnosis*; D012595:Scleroderma, Systemic / Q000097:blood / Q000175:diagnosis*; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D015415:Biomarkers; D001798:Blood Proteins; C002744:3-nitrotyrosine; D014443:Tyrosine