BACKGROUND: Because inflammation induces oxidative stress, exhaled hydrogen peroxide (H(2)O(2)), which is a marker of oxidative stress, may be used as a non-invasive marker of airway inflammation in chronic obstructive pulmonary disease (COPD). There are no data on the circadian variability of exhaled H(2)O(2) in COPD patients. OBJECTIVE: The aim of this study was to investigate the variability of the H(2)O(2) concentration in breath condensate of stable COPD patients and of matched healthy control subjects. METHODS: We included 20 patients with stable mild COPD (forced expiratory volume in 1 s approximately 70% of predicted) and 20 healthy subjects, matched for age, sex and pack-years, all smokers or ex-smokers. Breath condensate was collected and its H(2)O(2) concentration determined fluorometrically three times on day 0 (9 and 12 a.m., and 3 p.m.) and once on days 1, 2, 3, 8 and 21. RESULTS: The mean H(2)O(2) concentration increased significantly during the day in both the patient and control groups (p = 0.02 and p < 0.01, respectively). Over a longer period up to 21 days, the mean concentration did not change in both groups. There was no significant difference between patients and controls. The mean coefficient of variation over 21 days was 45% in the patient group and 43% in the control group (p = 0.8). CONCLUSIONS: The exhaled H(2)O(2) concentration increased significantly during the day in both stable COPD patients and controls. Over a period of 3 weeks, the mean H(2)O(2) concentration did not change and the variability within the subjects was similar in both groups. Copyright 2002 S. Karger AG, Basel
BACKGROUND: Because inflammation induces oxidative stress, exhaled hydrogen peroxide (H(2)O(2)), which is a marker of oxidative stress, may be used as a non-invasive marker of airway inflammation in chronic obstructive pulmonary disease (COPD). There are no data on the circadian variability of exhaled H(2)O(2) in COPDpatients. OBJECTIVE: The aim of this study was to investigate the variability of the H(2)O(2) concentration in breath condensate of stable COPDpatients and of matched healthy control subjects. METHODS: We included 20 patients with stable mild COPD (forced expiratory volume in 1 s approximately 70% of predicted) and 20 healthy subjects, matched for age, sex and pack-years, all smokers or ex-smokers. Breath condensate was collected and its H(2)O(2) concentration determined fluorometrically three times on day 0 (9 and 12 a.m., and 3 p.m.) and once on days 1, 2, 3, 8 and 21. RESULTS: The mean H(2)O(2) concentration increased significantly during the day in both the patient and control groups (p = 0.02 and p < 0.01, respectively). Over a longer period up to 21 days, the mean concentration did not change in both groups. There was no significant difference between patients and controls. The mean coefficient of variation over 21 days was 45% in the patient group and 43% in the control group (p = 0.8). CONCLUSIONS: The exhaled H(2)O(2) concentration increased significantly during the day in both stable COPDpatients and controls. Over a period of 3 weeks, the mean H(2)O(2) concentration did not change and the variability within the subjects was similar in both groups. Copyright 2002 S. Karger AG, Basel
Authors: Stefan Peters; Angelika Kronseder; Stefan Karrasch; Petra A Neff; Matz Haaks; Andreas R Koczulla; Petra Reinhold; Dennis Nowak; Rudolf A Jörres Journal: ERJ Open Res Date: 2016-06-17
Authors: Michael J Epton; Robin D Dawson; Wendy M Brooks; Simon Kingham; Teresa Aberkane; Jo-Anne E Cavanagh; Christopher M Frampton; Tracey Hewitt; Julie M Cook; Susan McLeod; Fiona McCartin; Katherine Trought; Leslie Brown Journal: Environ Health Date: 2008-05-14 Impact factor: 5.984