title: Protein nitration in chronic sinusitis and nasal polyposis: role of eosinophils.
abstract: OBJECTIVE
  To investigate the possible role of eosinophil peroxidase (EPO) in 3-nitrotyrosine (3NT) formation.
  
  
  METHODS
  Observational study employing immunocytochemistry to assess the presence of 3NT, inducible nitric oxide synthase (iNOS), eosinophils, mast cells, neutrophils, and lymphocytes in ethmoid sinus mucosal biopsies from normal controls and subjects with allergic and nonallergic chronic sinusitis and nasal polyposis.
  
  
  RESULTS
  3NT was more evident in biopsies from sinusitis patients (2.67 +/- 0.14, n = 21) than in healthy mucosa (0.43 +/- 0.2, n = 7, P < 0.01), but scores in atopic and nonatopic subjects were similar. Colocalization studies confirmed that 3NT was largely confined to eosinophils. No relationship was found between 3NT and other immune cells. 3NT detection was not correlated with the amount of immunostaining for iNOS.
  
  
  CONCLUSIONS
  Chronic sinusitis is accompanied by 3NT formation, which is largely restricted to the eosinophils, and likely driven by the action of eosinophil peroxidase, rather than by nitric oxide levels.
  
  
  METHODS
  B-2.
authors.affiliation: Meakins-Christie Laboratories, Respiratory Division, Department of Medicine, McGill University Health Centre, Montreal, QC H2X 2P2, Canada.
authors.forename: Julio Freire
authors.initials: JF
authors.lastname: Bernardes
authors.forename: Jichuan
authors.initials: J
authors.lastname: Shan
authors.forename: Marc
authors.initials: M
authors.lastname: Tewfik
authors.forename: Qutayba
authors.initials: Q
authors.lastname: Hamid
authors.forename: Saul
authors.initials: S
authors.lastname: Frenkiel
authors.forename: David H
authors.initials: DH
authors.lastname: Eidelman
mesh_terms: D000328:Adult; D000368:Aged; D002908:Chronic Disease; D047209:Eosinophil Peroxidase / Q000378:metabolism*; D004804:Eosinophils / Q000276:immunology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009298:Nasal Polyps / Q000276:immunology*; D012852:Sinusitis / Q000276:immunology*; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000096:biosynthesis*
chemical_list: C002744:3-nitrotyrosine; D014443:Tyrosine; D047209:Eosinophil Peroxidase