Nitrate in exhaled breath condensate of patients with different airway diseases
Section snippets
Study design
Preliminarily, we measured NO3− in EBC of healthy volunteers both with the chromatographic method and with the Griess method. The analysis of the degree of concordance (Bland and Altman test [13]) indicated the agreement of the two methods (Fig. 1).
In a preliminary study, we evaluated the reproducibility of the chromatographic method for the measurement of NO3− concentration in EBC. The difference in EBC NO3− concentrations measured during two successive collections at 2-h intervals (intraday
Results
All the subjects performed the EBC procedure without discomfort. NO3− levels in EBC measured with the chromatographic method were detectable in all subjects.
NO3− values were higher in smokers [median (range) 62.5 (9.6–158.0) μM] than in controls [9.6 (2.6–119.4) μM; p=0.003] (Fig. 3). NO3− levels positively correlated with the smoking history expressed as cigarettes per day (r=0.5, p=0.02). No correlation was observed between NO3− levels and smoking history expressed as pack–years and as exhaled
Discussion
The results of this study show high NO3− levels in EBC of asymptomatic smokers, asthmatics, and patients with CAP, but not in COPD patients in comparison to healthy nonsmoking subjects.
In this study NO3− concentrations in EBC were assayed using the chromatographic method. The chromatographic method for the measurement of NO3− has the advantages of minimal sample preparation and rapid analysis time (3 min per sample); therefore it is particularly suitable for assaying several samples at the same
Acknowledgements
The authors are grateful to Professor Bacciottini Franco and Dr. Friggeri Marco for their skillful assistance in the biochemical assays. We also thank Professor Paolo Montuschi for providing EBC samples of asthmatic patients.
References (22)
- et al.
Reversible reduction in plasma concentration of nitric oxide induced by cigarette smoking in young adults
Am. J. Cardiol.
(1997) - et al.
l-arginine-dependent production of nitrogen oxides by rat pulmonary macrophages
Eur. J. Pharmacol.
(1991) - et al.
Nitric oxide release accounts for the biological activity of endothelium-derived relaxing factor
Nature
(1987) Nitric oxide and airway disease
Ann. Med.
(1995)- et al.
Clinical aspects of exhaled nitric oxide
Eur. Respir. J.
(2000) - et al.
The biology of nitrogen oxides in the airways
Am. J. Respir. Crit. Care Med.
(1994) - et al.
Exhaled nitric oxide and bronchoalveolar lavage nitrite/nitrate in active pulmonary sarcoidosis
Am. J. Respir. Crit. Care Med.
(1997) - et al.
Reactive nitrogen species and tyrosine nitration in the respiratory tract: epiphenomena or a pathobiologic mechanism of disease
Am. J. Respir. Crit. Care Med.
(1999) - et al.
Nitrite and nitrate determinations in plasma: a critical evaluation
Clin. Chem.
(1995) - et al.
Peroxynitrite-induced luminol chemiluminescence
Biochem. J.
(1993)