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| 3. |
- Grubb, Tamara L, et al.
(författare)
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Physiologic responses and plasma endothelin-1 concentrations associated with abrupt cessation of nitric oxide inhalation in isoflurane-anesthetized horses
- 2008
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Ingår i: American Journal of Veterinary Research. - : American Veterinary Medical Association (AVMA). - 0002-9645 .- 1943-5681. ; 69:3, s. 423-430
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To assess physiologic responses and plasma endothelin (ET)-1 concentrations associated with abrupt cessation of nitric oxide (NO) inhalation in isoflurane-anesthetized horses. ANIMALS: 6 healthy adult Standardbreds. PROCEDURES: Horses were anesthetized with isoflurane in oxygen and placed in dorsal recumbency. Nitric oxide was pulsed into the respiratory tract for 2.5 hours, and then administration was abruptly discontinued. Just prior to commencement and at cessation of NO administration, and at intervals during a 30-minute period following cessation of NO inhalation, several variables including PaO(2), mean pulmonary artery pressure, venous admixture or pulmonary shunt fraction (Qs/Qt), and plasma ET-1 concentration were recorded or calculated. RESULTS: After cessation of NO inhalation, PaO(2) decreased slowly but significantly (172.7 +/- 29.8 mm Hg to 84.6 +/- 10.9 mm Hg) and Qs/Qt increased slowly but significantly (25 +/- 2% to 40 +/- 3%) over a 30-minute period. Mean pulmonary artery pressure increased slightly (14.0 +/- 1.3 mm Hg to 16.8 +/- 1 mm Hg) over the same time period. No change in serum ET-1 concentration was detected, and other variables did not change or underwent minor changes. CONCLUSIONS AND CLINICAL RELEVANCE: The improvement in arterial oxygenation during pulsed inhalation of NO to healthy isoflurane-anesthetized horses decreased only gradually during a 30-minute period following cessation of NO inhalation, and serum ET-1 concentration was not affected. Because a rapid rebound response did not develop, inhalation of NO might be clinically useful in the treatment of hypoxemia in healthy isoflurane-anesthetized horses.
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- Horvath, I., et al.
(författare)
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Exhaled breath condensate: methodological recommendations and unresolved questions
- 2005
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Ingår i: Eur Respir J. ; 26:3
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Tidskriftsartikel (refereegranskat)abstract
- Collection of exhaled breath condensate (EBC) is a noninvasive method for obtaining samples from the lungs. EBC contains large number of mediators including adenosine, ammonia, hydrogen peroxide, isoprostanes, leukotrienes, nitrogen oxides, peptides and cytokines. Concentrations of these mediators are influenced by lung diseases and modulated by therapeutic interventions. Similarly EBC pH also changes in respiratory diseases. The aim of the American Thoracic Society/European Respiratory Society Task Force on EBC was to identify the important methodological issues surrounding EBC collection and assay, to provide recommendations for the measurements and to highlight areas where further research is required. Based on the currently available evidence and the consensus of the expert panel for EBC collection, the following general recommendations were put together for oral sample collection: collect during tidal breathing using a noseclip and a saliva trap; define cooling temperature and collection time (10 min is generally sufficient to obtain 1-2 mL of sample and well tolerated by patients); use inert material for condenser; do not use resistor and do not use filter between the subject and the condenser. These are only general recommendations and certain circumstances may dictate variation from them. Important areas for future research involve: ascertaining mechanisms and site of exhaled breath condensate particle formation; determination of dilution markers; improving reproducibility; employment of EBC in longitudinal studies; and determining the utility of exhaled breath condensate measures for the management of individual patients. These studies are required before recommending this technique for use in clinical practice.
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- Janson, Christer, et al.
(författare)
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Risk factors associated with allergic and non-allergic asthma in adolescents
- 2007
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Ingår i: Clinical Respiratory Journal. - : Wiley. - 1752-6981 .- 1752-699X. ; 1:1, s. 16-22
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Risk factors for asthma have been investigated in a large number of studies in adults and children, with little progress in the primary and secondary prevention of asthma. The aim of this investigation was to investigate risk factors associated with allergic and non-allergic asthma in adolescents. Methods: In this study, 959 schoolchildren (13-14 years old) answered a questionnaire and performed exhaled nitric oxide ( NO) measurements. All children (n = 238) with reported asthma, asthma-related symptoms and/or increased NO levels were invited to a clinical follow-up which included a physician evaluation and skin-prick testing. Results: Asthma was diagnosed in 96 adolescents, whereof half had allergic and half non-allergic asthma. Children with both allergic and non-allergic asthma had a significantly higher body mass index (BMI) (20.8 and 20.7 vs. 19.8 kg/m(2)) (p < , 0.05) and a higher prevalence of parental asthma (30% and 32% vs. 16%) (p < , 0.05). Early-life infection (otitis and croup) [adjusted odds ratio ( OR) (95% confidence interval (CI)): 1.99(1.02-3.88) and 2.80 (1.44-5.42), respectively], pets during the first year of life [2.17 (1.16-4.04)], window pane condensation [2.45 (1.11-5.40)] and unsatisfactory school cleaning [(2.50 (1.28-4.89)] was associated with non-allergic but not with allergic asthma. Conclusion: This study indicates the importance of distinguishing between subtypes of asthma when assessing the effect of different risk factors. While the risk of both allergic and non-allergic asthma increased with increasing BMI, associations between early-life and current environmental exposure were primarily found in relation to non-allergic asthma.
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- Malinovschi, Andrei, et al.
(författare)
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Basal and induced NO formation in the pharyngo-oral tract influences estimates of alveolar NO levels
- 2009
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Ingår i: Journal of applied physiology. - : American Physiological Society. - 8750-7587 .- 1522-1601. ; 106:2, s. 513-519
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Tidskriftsartikel (refereegranskat)abstract
- The present study analyzed how models currently used to distinguish alveolar from bronchial contribution to exhaled nitric oxide (NO) are affected by manipulation of NO formation in the pharyngo-oral tract. Exhaled NO was measured at multiple flow rates in 15 healthy subjects in two experiments: 1) measurements at baseline and 5 min after chlorhexidine (CHX) mouthwash and 2) measurements at baseline, 60 min after ingestion of 10 mg NaNO3/kg body wt, and 5 min after CHX mouthwash. Alveolar NO concentration (CalvNO) and bronchial flux (J′awNO) were calculated by using the slope-intercept model with or without adjustment for trumpet shape of airways and axial diffusion (TMAD). Salivary nitrate and nitrite were measured in the second experiment. CalvNO [median (range)] was reduced from 1.16 ppb (0.77, 1.96) at baseline to 0.84 ppb (0.57, 1.48) 5 min after CHX mouthwash (P < 0.001). The TMAD-adjusted CalvNO value after CHX mouthwash was 0.50 ppb (0, 0.85). The nitrate load increased J′awNO from 32.2 nl/min (12.2, 60.3) to 57.1 nl/min (22.0, 119) in all subjects and CalvNO from 1.47 ppb (0.73, 1.95) to 1.87 ppb (10.85, 7.20) in subjects with high nitrate turnover (>10-fold increase of salivary nitrite after nitrate load). CHX mouthwash reduced CalvNO levels to 1.15 ppb (0.72, 2.07) in these subjects with high nitrate turnover. All these results remained consistent after TMAD adjustment. We conclude that estimated alveolar NO concentration is affected by pharyngo-oral tract production of NO in healthy subjects, with a decrease after CHX mouthwash. Moreover, unknown ingestion of dietary nitrate could significantly increase estimated alveolar NO in subjects with high nitrate turnover, and this might be falsely interpreted as a sign of peripheral inflammation. These findings were robust for TMAD.
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| 8. |
- Malinovschi, Andrei, 1978-
(författare)
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Nitric Oxide Exchange in Central and Peripheral Airways : Determinants in Health and Respiratory Disease
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Exhaled nitric oxide (NO) is a marker of eosinophilic steroid-sensitive inflammation in the airways of patients with respiratory disease. Moreover, information about the localization of inflammation in the respiratory tree is obtained by estimates of bronchial and alveolar contributions to exhaled NO.Aims: The main aim of this thesis was to identify the determinants of exhaled NO, as well as determinants of bronchial and alveolar contributions to exhaled NO in health and disease. Smoking history, degree of IgE sensitization and effects of modulating the pharyngo-oral tract production of NO were specifically studied in this context. Other specific aims were to determine the association of exhaled NO with the presence of asthma and pulmonary hypertension (PH).Methods: Both population-based studies and experimental studies have been performed within the frame of the thesis. The population-based studies are based on data from the European Community Respiratory Health Survey II. NO measurements at several exhalation flow rates were performed in order to estimate alveolar and bronchial contributions to exhaled NO.Results: Both current and previous smoking were associated with decreased exhaled NO and bronchial NO flux levels. Alveolar NO concentrations were decreased in current smokers. The degree of IgE sensitization was positively related to the levels of exhaled NO and its bronchial contribution. Exhaled NO appeared to be a more specific marker of allergic inflammation than of rhinitis or asthma. Both allergic and non-allergic asthma were associated with increased exhaled NO levels, but only in never-smoking persons. The estimated alveolar NO increased after ingestion of nitrate in individuals with high nitrate turnover in the pharyngo-oral tract. Pulmonary arterial hypertension, but not other forms of PH, was associated with decreased bronchial NO flux, whereas PH of all etiologies was related to increased alveolar NO concentrations.Conclusion: Smoking history and IgE sensitization, that are known determinants of exhaled NO, affected the bronchial and alveolar contributions to exhaled NO differently. The limitations of the simple NO pulmonary exchange models were highlighted by the paradoxical effects on estimated alveolar NO when modulating the NO production proximally, in the pharyngo-oral tract. Predominance of non-eosinophilic inflammation in ever-smoking patients with asthma could explain the poor association between the presence of asthma and exhaled NO in these patients. Different pathophysiological changes in terms of bronchial NO production and exchange were related to the etiology of pulmonary hypertension.
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| 9. |
- Nordvall, S. L., et al.
(författare)
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Exhaled nitric oxide in a population-based study of asthma and allergy in schoolchildren
- 2005
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Ingår i: Allergy. ; 60:4
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Tidskriftsartikel (refereegranskat)abstract
- Exhaled nitric oxide (NO) reflects inflammation in the lower airways and is well adapted for use in children. The aims of this study were to investigate the distribution of the fraction of expired NO (FE(NO)) in school children and to compare FE(NO) and spirometry in relation to the International Study of Asthma and Allergies in Childhood questionnaire. The study was performed in 959 randomly selected 13-14-year-old school children in Uppsala, Sweden. Exhaled NO was measured at an inhalation rate of 0.1 l/s (FE(NO0.1)) and a spirometric test was performed and data from these measurements were related to questionnaire data. Exhaled NO was measured according to American Thoracic Society recommendations, except the use of a mouth wash and an exhalation flow rate of 0.1 l/s. The distribution of the mean FE(NO0.1) values was skewed, with a preponderance of very low levels and a widespread tail of values ranging up to 102 parts per billion (ppb). Boys exhibited significantly higher mean FE(NO0.1) values than girls, 5.2 (4.7-5.7) vs 4.4 (4.0-4.8) ppb (geometric mean and 95% CI), P < 0.01). Children who reported wheezing in the last year had higher FE(NO0.1) values than children that had not, 8.5 (7.1-10.2) vs 4.3 (4.0-4.6) ppb, P < 0.001). The same association was found to most symptoms indicating hay fever and eczema. In contrast to this, only weak or inconsistent associations were found between asthma and spirometric indices. Exhaled NO levels were found to be independently related to male gender, wheeze and rhinoconjuctivitis but not to current eczema. In conclusion, exhaled NO was closely associated with reported asthma and allergy symptoms whereas spirometric indices such as percent predicted forced expiratory volume in 1 s were not. As most asthma cases in a population are mild, the findings suggest that exhaled NO is a sensitive marker of asthma and allergy.
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| 10. |
- Syk, Jörgen, et al.
(författare)
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Relationship between exhaled nitric oxide and IgE sensitisation in patients with asthma : influence of steroid treatment
- 2009
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Ingår i: Clinical Respiratory Journal. - 1752-6981 .- 1752-699X. ; 3:3, s. 143-151
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The influence of the degree of immunoglobulin E (IgE) sensitisation on the fraction of expired nitric oxide (FENO) in asthma patients being treated with inhaled corticosteroids (ICS) is not well known. Objectives: To investigate the relationship between IgE sensitisation and FENO, and the effect of a step-up in ICS treatment on this relationship, in patients with allergic asthma. Methods: A primary health care centre recruited 20 non-smoking patients with perennial allergic asthma (18 years-50 years, six male) outside the pollen season. At every visit (0, 2, 4, 8 weeks), FENO was measured and an exposure questionnaire was completed. ICS dose was adjusted according to FENO (>= 22 ppb prescribed increase in ICS). Quantitative analyses of serum IgE (eight common aeroallergens) confirmed allergy. Results: At baseline, FENO and the sum of IgE antibody titres for perennial allergens correlated significantly (r = 0.47, P = 0.04). After a step-up in ICS treatment, this correlation had disappeared. Nine patients had persistently elevated FENO at last visit (mean 35 ppb vs 16 ppb). This group was more frequently exposed to relevant allergens or colds (89% vs 27% of patients, P < 0.05) and had higher IgE antibody titres (perennial allergens) compared with the normalised group (mean 28.9 kU/L vs 10.7 kU/L, P < 0.05). Conclusion: Serum IgE against perennial allergens and FENO correlate in patients with allergic asthma. However, this relationship disappears after a high-dose ICS regimen, suggesting that FENO relates to bronchial inflammation and not IgE levels per se. High degree of IgE sensitisation together with allergen exposure may lead to ICS-resistant airways inflammation. Please cite this paper as: Syk J, Unden AL and Alving K. Relationship between exhaled nitric oxide and IgE sensitisation in patients with asthma: influence of steroid treatment. The Clinical Respiratory Journal 2009; 3: 143-151.
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