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- Svensson, Sophie, 1970, et al.
(författare)
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Determination of hydrogen peroxide in exhaled breath condensate by flow injection analysis with fluorescence detection
- 2004
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Ingår i: J Chromatogr B Analyt Technol Biomed Life Sci. ; 809:2
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Tidskriftsartikel (refereegranskat)abstract
- 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 40-5000nM. 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 (150microl) and no incubation time, and has an analytical runtime of <2min. 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), 780nM versus 480nM (P = 0.03).
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- Svensson, Sophie, 1970, et al.
(författare)
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Increased net water loss by oral compared to nasal expiration in healthy subjects.
- 2006
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Ingår i: Rhinology. - 0300-0729. ; 44:1, s. 74-7
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Tidskriftsartikel (refereegranskat)abstract
- AIM OF THE STUDY: To compare the difference in respiratory water loss during expiration through the nose and through the mouth, in healthy subjects. METHODS: The study included 19 healthy, non-smoking volunteers without any present history of non-infectious rhinitis, presenting with symptoms of rhinitis, asthma or previous nasal surgery. Nasal and oral expiratory breath condensates were collected using a breath condenser during tidal respiration at indoor resting conditions. During the nasal breath condensate sampling, the subjects were breathing into a transparent face mask covering the nose and the mouth with the mouth closed. During the oral breath condensate sampling, the subjects inhaled through the nose and exhaled through a mouthpiece connected to the condenser. The airflow during the sampling was assessed with a dry-spirometer connected to the condenser. Sampling was stopped after 100 litres of expired air for each breathing mode. Nasal sampling was done before and after decongestion of the nasal mucosa with oxymetazoline, 0.5 mg/ml. The effect on the nasal mucosa was assessed with acoustic rhinometry. RESULTS: The mean loss of expired water was 42% less by nasal expiration before decongestion than by oral expiration (1.9 x 10(-3) g/L min compared to 2.7 x 10(-3) g/L min, p < 0.001). The mean expiratory minute ventilation was 9.0 L/min by nasal respiration and 9.8 L/min by oral respiration. Decongestion of the nasal mucosa showed a mean increase of the cross-sectional area at 4 cm from the nostril (1.44 to 1.67 cm2, p = 0.0024), but there was no effect on the net water loss (1.9 x 10(-3) g/Lmin vs 1.9 x 10(-3) g/Lmin). CONCLUSION: This study showed that the net water loss increased by 42% when the breathing mode was switched from nasal to oral expiration during tidal breathing in healthy subjects. Increased water and energy loss by oral breathing could be a contributing factor to the symptoms seen in patients suffering from nasal obstruction.
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- Svensson, Sophie, 1970, et al.
(författare)
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Optimization and validation of an ion chromatographic method for the simultaneous determination of sodium, ammonium and potassium in exhaled breath condensate
- 2005
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Ingår i: J Chromatogr B Analyt Technol Biomed Life Sci. ; 814:1
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Tidskriftsartikel (refereegranskat)abstract
- 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 6min. 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 0.2muM 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.
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- Svensson, Sophie, 1970, et al.
(författare)
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pH in nasal exhaled breath condensate in healthy adults.
- 2007
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Ingår i: Rhinology. - 0300-0729. ; 45:3, s. 214-7
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes a new method to assess nasal pH in nasal exhaled breath condensate in adults. The study included 19 healthy, non-smoking, adult volunteers without current upper respiratory disease, COPD or asthma. Expiratory breath condensate (EBC) was collected from the nose and mouth respectively. A Jaeger breath condenser was fitted with a transparent facemask and during oral sampling it was fitted with a mouthpiece. The condensates were bubbled with argon gas for 10 minutes to reduce carbon dioxide and the samples were analysed immediately using a calibrated glass electrode and a portable pH-meter. The mean pH in the nasal EBC was 7.0 +/- 0.5 and in oral EBC 6.9 +/- 0.7 (p = 0.6). The nasal EBC-pH was well in agreement with data from previous studies, which measured pH directly on the nasal mucosa with an electrode. In conclusion, this paper describes a method to measure pH in nasal exhaled breath condensate (EBC) in healthy adults during tidal breathing. The nasal EBC-pH related well to previous data from intranasal pH measurements suggesting that nasal EBC-pH could have a role in monitoring pH alterations in the nasal mucosa such as nasal inflammation.
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