title: Exhaled NO in asthmatic children in unpolluted and urban environments.
abstract: BACKGROUND
  NO production (NOex) in the airway epithelium is increased in asthmatic patients and is potently inhibited by anti-inflammatory treatments. The study was designed to compare the: (i) levels of NOex in two groups of asthmatic children residing in different environments (one in a national park in the mountains and the other in a large city) and (ii) the influence of glucocorticoids on levels of NOex between the children and those without treatment.
  
  
  METHODS
  The measurements were performed during the same period in the two locations, 100 km apart. NOex was measured using a chemiluminescence analyzer in controls and two comparable groups of asthmatic children. The first group included 63 children (10+/-3 years) recruited from a specialized institution for asthmatic children, and the second group consisted of 46 asthmatic children (9+/-3 years) living in an urban area. A reference group of 17 healthy children residing in the same city was also studied.
  
  
  RESULTS
  The concentrations of NOex in children in the specialized institution were significantly lower (P<.001) than those in asthmatic children living in the city (5.1+/-2.4 vs. 13.8+/-9.3 ppb) and comparable to those in healthy controls (5.3+/-4.0 ppb). In the urban area, NOex levels increased when atmospheric pollution recorded on the previous day had increased. In contrast to that observed in the urban children, glucocorticoids had little influence on the levels of NOex in the children living in the specialized institution.
  
  
  CONCLUSIONS
  Although these relationships need to be confirmed, our findings show that for the determination of NOex, specifying the quality of the environment, in particular, the purity of the air respired by asthmatic children, not only at the time of measurement but also over the previous days, is important.
authors.affiliation: INSERM Unité 518 Epidémiologie et Analyses en Santé Publique: Risques, Maladies Chroniques et Handicaps, Hôpital La Grave, Toulouse, France. saulet@purpan.inserm.fr
authors.forename: M
authors.initials: M
authors.lastname: Giroux
authors.forename: F
authors.initials: F
authors.lastname: Brémont
authors.forename: J
authors.initials: J
authors.lastname: Ferrières
authors.forename: J C
authors.initials: JC
authors.lastname: Dumas
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects* / Q000032:analysis; D000397:Air Pollution; D001249:Asthma / Q000188:drug therapy / Q000503:physiopathology*; D001944:Breath Tests; D002648:Child; D005260:Female; D005602:France; D005938:Glucocorticoids / Q000627:therapeutic use; D006633:Histamine Antagonists / Q000627:therapeutic use; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000096:biosynthesis*; D013147:Spirometry; D013997:Time Factors; D014505:Urban Population
chemical_list: D000393:Air Pollutants; D005938:Glucocorticoids; D006633:Histamine Antagonists; D009569:Nitric Oxide