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PubMed2004

Determination of hydrogen peroxide in exhaled breath condensate by flow injection analysis with fluorescence detection.

A method for the determination of hydrogen peroxide in exhaled breath condensate (EBC) by automated flow injection analysis (FIA) with fluorescence detection was developed and validated. In the enzymatic assay a fluorescent dimer of para-hydroxyphenyl acetic acid (HPAA) was formed by the redox coupling reaction between hydrogen peroxide and horseradish peroxidase (HRP). The calibration curve of hydrogen peroxide was linear over a range of 40-5000 nM. The coefficient of variation (CV) for within-day precision was 1-3%; for between-day precision, it was 2-5% over the validated range. The assay requires a small sample aliquot (150 microl) and no incubation time, and has an analytical runtime of < 2 min. It is therefore suitable for larger studies. The method was used to detect hydrogen peroxide in EBC of asthmatic patients and healthy volunteers. A statistically significant difference was found between patients with asthma (n = 19) and control subjects without asthma (n = 19), 780 nM versus 480 nM (P = 0.03).

Asthma↗
PubMed2005

Optimization and validation of an ion chromatographic method for the simultaneous determination of sodium, ammonium and potassium in exhaled breath condensate.

An ion chromatographic method with conductivity detection for the simultaneous quantification of sodium, ammonium and potassium in exhaled breath condensate (EBC) was developed and validated. A factorial design was used to optimize the chromatographic conditions, which resulted in baseline separations of the cations within 6 min. The method requires no pre-treatment of EBC samples. The optimized method was used for the intra-individual screening of cations in EBC of 10 healthy volunteers. The LOQs were low (0.3, 0.1 and 0.2 microM for sodium, ammonium and potassium, respectively), compared with levels detected in healthy volunteers. The responses were linear with good precision, and samples could be stored for at least 10 weeks at refrigerating conditions.

Breath Tests↗
PubMed2005

Radon exhalation of cementitious materials made with coal fly ash: Part 1--scientific background and testing of the cement and fly ash emanation.

Increased interest in measuring radionuclides and radon concentrations in fly ash, cement and other components of building products is due to the concern of health hazards of naturally occurring radioactive materials (NORM). The current work focuses on studying the influence of fly ash (FA) on radon-exhalation rate (radon flux) from cementitious materials. The tests were carried out on cement paste specimens with different FA contents. The first part of the paper presents the scientific background and describes the experiments, which we designed for testing the radon emanation of the raw materials used in the preparation of the cement-FA pastes. It is found that despite the higher (226)Ra content in FA (more than 3 times, compared with Portland cement) the radon emanation is significantly lower in FA (7.65% for cement vs. 0.52% only for FA).

Air Pollutants, Radioactive↗
PubMed2005

Validity criteria and comparison of analytical methods of flow-independent exhaled NO parameters.

The objective was to assess both validity and comparability of multiple constant (MCF, mainly performed) and dynamically changing (DCF, new method) flow analyses calculating alveolar concentration (Calv(NO)), maximum conducting airway flux (J'aw(NO)) and airway diffusing capacity (Daw(NO)) of exhaled NO (FE(NO)). (Calv(NO), J'aw(NO))(R) where R is the correlation coefficient of the linear regression between NO output and expiratory flow rate (MCF) and (Calv(NO), J'aw(NO), Daw(NO))(Delta100) where Delta100 is the ratio ([observed-predicted FE(NO)]/observed FE(NO)) at 100 ml/s (DCF) were assessed in 18 healthy subjects (10 atopic). MCF demonstrated a linear relationship (R > or = 0.80) between NO output and expiratory flow in 15/18 subjects. DCF was valid (Delta100 < or = 30%) in 12/18 subjects. A good agreement between MCF and DCF was evidenced in the nine subjects with R > or = 0.80 and Delta100 < or = 30%. Failure of validity criteria was mainly observed in atopic subjects. In conclusion, when validity criteria are satisfied, the new DCF method similarly characterizes NO exchange parameters than MCF approach.

Adult↗
PubMed2005

Does consumption of ethanol distort measurements of exhaled nitric oxide?

BACKGROUND: Measuring FE(NO) is a novel and non-invasive way to monitor airway inflammation (e.g. asthma). This clinical study was designed to investigate whether drinking ethanol might distort FE(NO) measurements. METHODS: Twenty healthy subjects drank 0.40 g ethanol/kg body weight in 15 min. Measurement of FE(NO) started approximately 30 min before drinking and at various times afterwards for 4 h post-dosing. Ethanol concentrations were determined in venous blood by gas chromatography and in end-exhaled breath by infra-red spectrometry. RESULTS: The within subject standard deviation for determination of FE(NO) was 1.3 ppb, corresponding to a CV of 7.7%. The mean change in FE(NO) from pre-drinking levels during the 4h testing was statistically significant (P<0.001) according to repeated measures ANOVA. In absolute units the mean change was small, -2.01 and -1.94 ppb at 3 and 4h post-dosing, respectively (P<0.013, P<0.005). CONCLUSIONS: FE(NO) measurements were reproducible even in subjects with moderate concentrations of ethanol in blood and breath. The small decrease in FE(NO) observed at 3 and 4 h post-drinking was less than the intra-subject variations in FE(NO) measurements. The breath-alcohol concentrations in this study exceed all other endogenous volatiles, thus making it unlikely that other substances in human breath will bias the FE(NO) measurements.

Adult↗
PubMed2004

Comparison of exhaled nitric oxide analysers.

Currently no published data are available concerning the comparability of different types of NO analysers, making inter-laboratory comparisons difficult. In two sets of experiments we compared 4 and 5 NO analysers, respectively, from 3 different manufacturers using different calibration regimes: calibration with (1) a separate recommended calibration gas for each analyser, (2) a single low concentration for all (394 ppb), and (3) a single high concentration (12.8 ppm). We measured three subjects with known low (L), moderate (M) and high (H) bronchial exhaled nitric oxide concentrations as well as standard gases (SG). In the first set of experiments, calibration regime 1 resulted in the largest differences between analysers (coefficient of variation (CV) for L, M, H, SG: 0.42, 0.22, 0.20, 0.14). The lowest CV between analysers was observed after calibration 2 (0.34, 0.19, 0.12, 0.02). Very similar results were obtained in the second set of comparisons. Thus, differences between analysers existed, but were mainly due to differences in recommended calibration gases/procedures. Only a small part was explainable by deviations from target flow. These differences need to be taken into account when comparing data between laboratories or replacing the calibration gas of an analyser, as well as for the establishment and interpretation of normal values.

Adult↗
PubMed2005

The influence of inhaled corticosteroids on exhaled nitric oxide in stable chronic obstructive pulmonary disease.

The aim of the study was to evaluate the exhaled nitric oxide (F(ENO)) in clinically stable chronic obstructive pulmonary disease (COPD), its relationship to the severity of the disease, pulmonary function, smoking status, reversibility of airflow limitation, and ICS therapy. The study was conducted in 47 patients with COPD and 40 healthy controls. Flow/volume spirometry and F(ENO) measurement were performed before and after 2 months of ICS therapy. F(ENO) were significantly elevated in current smokers and ex-smoking COPD patients. In both groups of COPD patients inhaled corticosteroids (ICS) therapy caused a significant decrease in F(ENO) without significant changes in FEV1. A positive correlation between initial F(ENO) and postbronchodilator FEV1 (% predicted) was observed in the group of ex-smoking COPD patients, but not in the currently smoking COPD group. In both groups of COPD patients, the initial level of F(ENO) correlated with the reversibility of airway obstruction, the increase in postbronchodilator FEV1 and the decrease in F(ENO) following ICS treatment. F(ENO) increases in patients with stable COPD. ICS therapy decreased elevated F(ENO) levels in these patients without statistically significant changes in lung function. The selection of COPD patients with increased F(ENO) level and partial reversibility of airway obstruction should be helpful in terms of proposed ICS treatment.

Administration, Inhalation↗
PubMed2005

Exhaled breath condensate cytokine patterns in chronic obstructive pulmonary disease.

Differences in cytokine patterns in stable chronic obstructive pulmonary disease (COPD), exacerbated COPD, smokers without apparent COPD, and healthy volunteers should be of interest for pathophysiological and therapeutic reasons. Methods including lavage, biopsy and sputum have been employed to investigate cytokines in the lung. For asystematic comparison, exhaled breath condensate (EBC) appears to be well suited. We investigated healthy volunteers, smokers without apparent COPD, stable and exacerbated COPD patients (+/- inhalative steroids) and finally those whose exacerbation made mechanical ventilation inevitable, for a more complete picture of inflammatory cytokines in COPD. We chose EBC because it is non-invasive and can be used repeatedly in spontaneous breathing individuals and during mechanical ventilation. EBC cytokines (IL-1 beta, IL-6, IL-8, IL-10, IL-12 p 70, TNF-alpha) were assayed from a single sample using a multiplex array test kit. We observed a significant increase of all cytokines in acute exacerbation compared to stable COPD, smokers, and volunteers. Stable COPD and volunteers exhibited only small differences in cytokine pattern with respect to IL-1 beta and IL-12 (P<0.01). Smokers had increased levels of all investigated cytokines (P<0.01) compared to non-smokers and, with the exception of IL-1 beta, to stable COPD. Inhaled steroids resulted in reduced levels of IL-1 beta, IL-6, IL-8, IL-10, and IL-12 (all: P<0.01) in stable COPD (all: ex-smokers) with dose dependency for IL-8, IL-1 beta and IL-12. EBC analysis successfully characterized important differences in stable COPD compared to exacerbation or smoking and non-smoking healthy individuals.

Adult↗
PubMed2005

Exhaled carbon monoxide levels in atopic asthma: a longitudinal study.

Exhaled carbon monoxide (eCO) is a potential non-invasive marker of airway inflammation. We have investigated the cross-sectional and longitudinal relationship between eCO and lung function and bronchial reactivity in 69 adults with atopic asthma, in the course of participation in a 6-week randomised placebo-controlled trial of vitamin E supplementation. At baseline, there was no cross-sectional association between absolute eCO levels and either forced expiratory volume (FEV(1)), forced vital capacity (FVC) or bronchial reactivity. However, in the longitudinal analysis within the placebo group, a rise in mean eCO was significantly associated with improvement in bronchial reactivity (change in eCO (parts per million) per natural log unit change in bronchial hyperreactivity 0.498, 95% confidence interval 0.071 to 0.924, P=0.024). These findings suggest that, contrary to previous data, there is no cross-sectional relationship between eCO and lung function or bronchial reactivity, but that there may be a longitudinal trend with bronchial reactivity that is worth further investigation.

Adolescent↗
PubMed2006

Variability of nitric oxide metabolites in exhaled breath condensate.

The collection of exhaled breath condensate (EBC) is simple and non-invasive, however, there are few data on the methodological aspects affecting concentrations of compounds in EBC. The aim of this study was to investigate methodological issues for measuring nitric oxide metabolites (NO(x)) in EBC. Twenty-five healthy adults (12 females, age range 23-55 years) and 22 children (11 females, age range 7-6 years) were recruited for studies investigating inter- and intra-day repeatability, repeatability with controlled expiratory flows and temperature, flow dependence, and analytical variability of EBC NO(x). Both intra- and inter-day repeatability was poor with a coefficient of repeatability of 103.4% of the mean difference between intra-day (15 min) measures and 118.6% of inter-day (24 h) differences. Repeatability was not improved when expiratory flow and temperature of the collection device were controlled. However, some of the variability (approximately 50%) may be accounted for by variability in the analytical technique (analytical variability) and this may result from difficulties in controlling for contamination. NO(x) levels were not affected by different expiratory flows in either adults or children but there was still significant variation within individuals. Levels of NO(x) in EBC seem to be highly variable and this needs to be considered if EBC NO(x) is to be used in clinical studies.

Adult↗
PubMed2006

Methodological improvements for measuring eicosanoids and cytokines in exhaled breath condensate.

BACKGROUND: Exhaled breath condensate (EBC) is simple to collect and as such a non-invasive method that has attracted substantial interest in the last few years. However, several methodological concerns have been raised and it has been difficult to reproduce results between different centres. Because of low concentrations of inflammatory markers, potential loss in the sampling system may have great influence. The aim of the present study was to se if evaporation and plastic coating could facilitate detection. METHODOLOGY: Through methodological improvements, we have now made it possible to measure EBC concentrations of eicosanoids and cytokines in our system. Due to absorbance of both fatty acid derivates and proteins to several plastics, the first step is coating of all surfaces with bovine serum albumin and Tween 20. Since several assays are sensitive to these factors, the methodology has to be standardised to avoid false results. Secondly, larger amounts of EBC have to be vacuum-dried, and thereafter resolved in the respective assay buffers. The EBCs have to be concentrated 5-10 times, depending on samples and assay sensitivity. RESULTS: Due to these improvements we can measure, for example, cysteinyl-leukotrienes, leukotriene B4, prostaglandin E and 8-isoprostane. High sensitivity assays have also made it possible to measure cytokines, for example, interleukin (IL)-1beta, IL-8 and IL-13. SUMMARY: We are aware of different results from other labs. However, it seems essential to coat and to concentrate the samples in order to achieve reliable and measurable results.

Adult↗
PubMed2005

Exhaled breath condensate levels of 8-isoprostane, growth related oncogene alpha and monocyte chemoattractant protein-1 in patients with chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) patients have increased neutrophils and macrophages in their lungs, and inflammation of the airway is related to oxidative stress. This study assessed the levels of 8-isoprostane (an oxidative stress marker) and chemokines related to neutrophil and monocyte inflammation (growth-related oncogene alpha [GROalpha] and monocyte chemoattractant protein-1 [MCP-1]) in the airway of ex-smoking COPD patients by exhaled breath condensate (EBC) collection. Thirty-two (28 males) stable COPD patients (14 with FEV(1) 50% [Group 1], 18 with FEV(1) <50% predicted [Group 2]) and 18 non-smoking age and sex-matched controls were studied in this cross-sectional study. EBC was collected using the EcoScreen (Jaeger, Germany) during 10 min of tidal breathing with the nose clipped. Concentrations of 8-isoprostane, GROalpha and MCP-1 were measured by enzyme immunoassays. COPD patients had a higher concentration of 8-isoprostane than controls (COPD versus control, P<0.001; Group 1 versus Group 2, P=0.045). 8-isoprostane increased across the groups from normal, Group 1 to Group 2 (r=0.64, P<0.001). The median intraquartile range (IQR) levels in pg/ml for GROalpha were 45.3(44.5-46.5), 45.4(44.5-46.0), 46.0(45.6-47.3), whereas MCP-1 levels were 5.3(5.2-5.9), 6.2(5.4-6.9) and 5.7(5.5-6.4) in Group 1, Group 2 COPD and control subjects, respectively. GROalpha level was lower in COPD patients when compared to controls (P=0.01). MCP-1 level did not differ between COPD and the control group. 8-isoprostane level, but not GROalpha and MCP-1, in EBC was increased in COPD patients with poorer lung function. This suggests an increased oxidative stress in the airway in patients with more severe COPD.

Aged↗
PubMed2005

Single breath N2-test and exhaled nitric oxide in men.

The N(2) slope is an index of inhomogeneous distribution of ventilation and has been suggested to be suited for early testing of chronic obstructive pulmonary disease (COPD) in smokers. The aim of the present study was to examine the association between the fraction of exhaled nitric oxide (FENO) and the N(2) slope in a random population of smoking and non-smoking men. Altogether 57 subjects were included in the study, 24 never-smokers, seven ex-smokers and 26 current smokers. Subjects were examined twice, in 1995 when they regarded themselves as healthy, and in a follow-up in 2001. Spirometry, N(2) slope and high-resolution computed tomography (HRCT) were performed in 1995 while the follow-up examination included also measurement of FENO. The FENO value was significantly lower and the N(2) slope higher in current smokers. In smokers but not in never- or ex-smokers FENO was correlated to the difference in N(2) slope between 1995 and 2001 (r(s)=0.49, P=0.01). We analysed the data by multiple linear regression adjusted for smoking, mild respiratory symptoms and inhaled steroids. There were significant associations between FENO and the N(2) slope both in 1995 and in 2001. The strongest association was found to exist with the change in N(2) slope during these years. Sixteen of the subjects could be classified as having COPD, six with mild and ten with moderate COPD. There was a trend for an increase in N(2) slope with increased severity of COPD; among subjects with no COPD the N(2) slope in 2001 was 2.3% N(2)/L, and those with mild and moderate COPD had 2.5% N(2)/L and 3.9% N(2)/L, respectively (P=0.0004). No such trend was seen for FENO (17.8, 15.5 and 20.3 parts per billion (ppb), respectively, P=0.8). The results show that FENO is associated with the N(2) slope, indicating that FENO reflects inflammatory changes in the peripheral airways of both non-smoking and smoking subjects.

Aged↗
PubMed2006

Effect of ciclesonide and fluticasone on exhaled nitric oxide in patients with mild allergic asthma.

Ciclesonide is a novel, lung-activated, inhaled corticosteroid with once-daily efficacy and potent anti-inflammatory activity. The aim of the study was to compare the effect of ciclesonide and fluticasone propionate on exhaled nitric oxide (FENO), pulmonary function, and other parameters used in clinical evaluation of patients with mild allergic asthma. The study indicates that ciclesonide (in a daily dose of either 80 or 160 microg) induces both a faster and stronger decrease of FENO in comparison with fluticasone (100 microg twice daily). In both groups of patients treated with ciclesonide, the highest decrease in FENO levels was observed after 2 weeks of treatment. In the group of patients treated with fluticasone, this maximum effect was not observed till 8 weeks. An improvement in spirometric indices was observed in all groups studied. Statistical differences between the groups were not found; however, there was a trend toward higher increase in the group receiving 160 microg of ciclesonide. In all groups studied we observed clinical improvement (asthmatic symptoms and consumption of rescue medication were reduced), but there were no significant differences between these groups. Our results indicate that ciclesonide, compared with fluticasone, has stronger anti-inflammatory activity in patients with mild allergic asthma.

Adult↗
PubMed2006

Short-term and seasonal variations of exhaled and nasal NO in healthy subjects.

Nitric oxide (NO) is an important biological mediator with a variety of cellular and tissue functions. Fractional exhaled (FE(NO)) and nasal NO (FN(NO)) are known to be altered in several respiratory tract disease and disorders. However, there are rather few studies into the reproducibility of FE(NO) or FN(NO) measurements in healthy subjects. The aim of this study was to examine both short- and long-term variations of FE(NO) and FN(NO). In addition to intraday, day-to-day and week-to-week variations, the seasonal variation was assessed. The data revealed that FE(NO) and FN(NO) levels were lower in the mornings compared to the afternoon values. There were clinically significant correlations in day-to-day (morning values 121.4+/-37.5 vs. 119.8+/-29.6, r=0.868, P=0.000), week-to-week (morning values 121.4+/-37.5 vs. 128.0+/-32.1, r=0.637, P=0.000) and seasonal (winter 133.5+/-29.7, summer 138.1+/-47.6, autumn 121.4+/-37.5, r=0.624, P=0.000) values of FN(NO). Day-to-day (morning values 14.6+/-6.7 vs. 14.2+/-5.1, r=0.784, P=0.000) week-to-week (morning values 14.6+/-6.7 vs. 15.4+/-7.3, r=0.738, P=0.000) and seasonal (autumn 14.6+/-7.2, winter 16.6+/-6.4, summer 17.4+/-8.0, r=0.709, P=0.000) levels of FE(NO) were also highly reproducible. Serial FE(NO) and FN(NO) measurements can be used in the monitoring of respiratory tract inflammation. Due to the diurnal variation of FE(NO) and FN(NO,) in long-term follow-up the measurements should be performed at the same time of day.

Adult↗
PubMed2005

Collection of exhaled breath condensate and analysis of hydrogen peroxide as a potential marker of lower airway inflammation in cats.

The objective of this study was to describe a standardised and non-invasive method for exhaled breath condensate (EBC) collection in cats and to test whether determination of hydrogen peroxide (H(2)O(2)) in EBC might be used as marker of lower airway inflammation. The technique of barometric whole body plethysmography for cats was combined with a system to condense the effluent air from the plethysmograph, allowing simultaneous EBC collection and respiratory pattern measurement. H(2)O(2) was determined spectrophotometrically. Eighteen experimental cats were used to investigate the impact on EBC volume and EBC H(2)O(2) of plethysmograph ventilation rate, collection duration, sample stability, within-day and day-to-day variability. After determination of a standardised EBC collection procedure, correlation analyses between EBC H(2)O(2) and bronchoalveolar lavage (BAL) cytology of healthy and allergen-challenged Ascaris suum (AS)-sensitised cats were performed. A significant and positive correlation between EBC H(2)O(2) and bronchoalveolar lavage (BAL) neutrophil% was found in healthy cats (P < 0.001, r = 0.55), whereas in AS-sensitised cats, correlation with BAL eosinophil% was significant (P < 0.005, r = 0.61). H(2)O(2) was increased after an allergen challenge in AS-sensitised cats (n = 6, 0.56+/-0.12 versus 1.08+/-0.35 micromol/L, P < 0.05). This study proposes a non-invasive, well tolerated and repeatable method of EBC collection for cats and suggests that EBC H(2)O(2) might be used as non-invasive biomarker for monitoring lower airway inflammation.

Airway Obstruction↗
PubMed2003

Exhaled breath condensates: a potential novel technique for detecting aspiration.

There is an urgent need for diagnostic procedures that can detect aspiration of oral and gastrointestinal (GI) secretions into the respiratory tract. Current approaches are limited by poor sensitivity and specificity. These techniques include (1) adding indicators to feedings; (2) recovery of lipid-filled macrophages in respiratory secretions; (3) measurement of changes in the pH of the upper GI and respiratory tracts; (4) endoscopic visualization of reflux events; and (5) measurement of increased glucose concentrations in respiratory secretions. Ideally, specific markers from various sites in the oral and GI tracts might be discovered in respiratory secretions, but conventional bronchoalveolar lavage for sampling respiratory secretions is not practical and involves some risk. Noninvasive measurements of indicators in the exhaled breath condensates could be used to detect aspiration, but a number of theoretical and practical aspects of such studies must be considered before this approach can be applied to the problem of aspiration.

Breath Tests↗
PubMed2001

A fast chemiluminescent method for H(2)O(2) measurement in exhaled breath condensate.

BACKGROUND: Breath condensate can give useful information on volatile compounds produced at alveolar level. Actual concentration of H(2)O(2) in breath condensate is dependent on its production at alveolar level and on the efficacy of the detoxifying systems, catalase, glutathione peroxidase, etc. METHODS: In the present paper, a simple chemiluminescent method for the determination of the H(2)O(2) collected in exhaled breath is shown and data of both smokers and nonsmokers volunteers are presented. RESULTS: The chemiluminescent response is linear up to 100 micromol/l H(2)O(2). The analytical sensitivity is about 0.01 micromol/l. Most of the nonsmokers have a H(2)O(2) content lower than 0.05 micromol/l, while smokers have a content ranging from 0.1 to 0.6 micromol/l.

Adult↗