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At least 73 records · Page 4Linked to original sources
PubMed2000

Exhaled nitric oxide in systemic sclerosis: relationships with lung involvement and pulmonary hypertension.

OBJECTIVE: To measure nitric oxide (NO) concentration in exhaled air of patients with systemic sclerosis (SSc) and to investigate its relationships with lung involvement, complicated or not by pulmonary hypertension (PH). METHODS: Exhaled NO was measured by chemiluminescence in 47 patients with SSc (16 with PH) and in 30 controls. All the patients underwent Doppler echocardiography to assess pulmonary artery pressure (PAP), lung function tests, and thin section computed tomographic scans of the lung to quantify the extent of fibrosing alveolitis. RESULTS: Exhaled NO levels were higher in patients with SSc (16.6 +/- 9.1 ppb), particularly those with interstitial lung disease (ILD) (18.3 +/- 10.4 ppb), compared to controls (9.9 +/- 2.9 ppb; p < 0.0001). In patients with PH, exhaled NO was less than in patients without PH (10.7 +/- 5.9 vs 19.6 +/- 9 ppb, respectively; p < 0.001), and patients with PH without ILD had even lower exhaled NO than patients with PH and ILD (6.6 +/- 1.1 vs 12.6 +/- 6.3 ppb; p = 0.004). There was an inverse correlation between PAP and exhaled NO (r = 04).53, p = 0.004). Exhaled NO was not correlated to age, disease duration, current therapy, or form of disease (limited or diffuse). CONCLUSION: The increased concentration of exhaled NO in patients with SSc may reflect respiratory tract inflammation. The relatively low value of exhaled NO in patients with PH and the negative correlation between PAP and exhaled NO suggest the important role of NO in regulating pulmonary vascular resistance in patients with SSc.

Adult↗
PubMed1998

[Measurement of exhaled nitric oxide in healthy subjects].

BACKGROUND: Endogenously synthesized nitric oxide (NO) is present in exhaled air and its analysis could be used as a tool to monitor inflammatory airway diseases. The objective of the present study was to develop the methodology for the measurement of exhaled NO and to obtain reference values in a group of healthy subjects. SUBJECTS AND METHOD: Exhaled NO was measured in 40 healthy subjects and 22 asthmatic patients using a single breath manoeuvre and a chemiluminescence analyzer. Comparisons of exhaled NO while breathing both, room air and medical air, were performed in 20 subjects. In seven asthmatic patients we evaluated the effect of an inhibitor of NO-synthesis (L-NAME). RESULTS: Mean (SD) exhaled NO in healthy subjects was 18 (13) parts per billion (ppb). Intraindividual variability was 6.5 (6.5%). The concentration of exhaled NO could be overestimated when environmental NO was high (> 80 ppb). Smokers showed lower levels than nonsmokers (10 [7] vs 22 [13] ppb, respectively; p < 0.005), whereas asthmatic patients showed higher exhaled NO levels (62 [31] ppb; p < 0.001). In these patients nebulization of L-NAME induced a progressive fall in exhaled NO (maximal decrease, -68 [15%]; p < 0.01). CONCLUSIONS: The measurement of NO concentration in exhaled air is reproducible, not influenced by the usual levels of environmental NO, and sensible enough to detect changes induced by the administration of a specific inhibitor. Exhaled NO concentration decreases in smokers and increases in asthmatics.

Adult↗
PubMedDate not supplied

Exhaled breath condensate as matrix for toluene detection: a preliminary study.

The study was designed to investigate whether exhaled breath condensate, obtained by cooling exhaled air in spontaneous breathing, could be a suitable matrix for toluene quantitative analyses. Nine healthy subjects were exposed for a short period (20 min) to a known concentration of toluene. Exhaled breath condensate samples were collected before and at the end of the exposure, while the environmental concentration of toluene was continuously monitored. Toluene was analysed by head-space gas-chromatography mass spectrometry, and assay repeatability was also estimated in vitro. Baseline and post-exposure measurement of hippuric acid, the urinary toluene metabolite, was performed to assess current toluene exposure. Before the exposure toluene concentrations in the exhaled breath condensate were lower than the detectable limit in all subjects, while after the exposure toluene was detectable with a median value 0.35 microg l-1 (range 0.15-0.55 microg l-1) in all the exhaled breath condensate samples. As compared with the standard calibration in distilled water, the curves obtained by exhaled breath condensate were linear and comparable with the range examined in vivo for toluene. A significant correlation was found between the environmental toluene levels and toluene in the exhaled breath condensate at the end of exposure. Furthermore, a significant relationship between increased exhaled breath condensate toluene levels and urinary hippuric acid after the exposure was found. In conclusion, exhaled breath condensate is a promising matrix for toluene assessment, although its application in humans requires further investigations.

Adult↗
PubMed2004

[Exhaled nitric oxide (NO) in patients with respiratory tract diseases].

Nitric oxide (NO) is highly active molecule playing a key role in physiological as well as in pathological processes in the organism. Asthmatic patients show an increased expression of inducible nitric oxide synthase (iNOS) in airway epithelial cells and an increased level of NO in exhaled air. The aim of the study was to evaluate the exhaled NO in different groups of allergic patients and healthy volunteers. The study was conducted in the group of 94 patients and healthy subjects. NO was measured in exhaled air by means of chemiluminescence (model 280 nitric oxide analyzer. Sievers Instruments, Inc, USA. Healthy, nonsmoking subjects had exhaled NO levels of 10-20 ppB and smoking was one of the factors reduces exhaled NO. Exhaled NO was elevated in asthma patients. The patients with stable COPD have been shown to have exhaled NO on the same level that healthy smoking subjects. We observed, that the study patients with pollinosis who did not have asthma symptoms had increased levels of exhaled NO during pollen season. Measurement of exhaled NO is an easy, non-invasive procedure that can be used to monitor the level of airway inflammation.

Adolescent↗
PubMed1999

Reference values of exhaled nitric oxide for healthy children 6-15 years old.

Nitric oxide (NO) can be detected in human exhaled air, and its endogenous production is increased in patients with asthma. It may provide a noninvasive means for measuring airway inflammation. The aim of this study was to establish reference values for exhaled NO concentrations in a large number of healthy school-age children. We measured exhaled NO levels in 159 white healthy children (88 girls, 71 boys, age range 6-15 years) recruited from two public schools of Padua, Italy. Exhaled NO levels in exhaled gas were measured by a tidal breathing method with a chemiluminescence analyzer, and NO steady-state levels were recorded. Nasal NO levels were measured by direct sampling from the nose during mouth breathing. The mean concentration of endogenous NO in orally exhaled gas was 8.7 parts per billion (ppb) (95% confidence interval (C.I.), 8.1-9.2 ppb) and sampled data followed a log-normal distribution (Kolmogorov-Smirnov d = 0.77, P > 0.2). No difference was found between boys (mean value, 8.4 ppb; 95% C.I., 7.3-9.4 ppb) and girls (mean value, 8.9 ppb; 95% C.I., 7.9-9.9 ppb). No significant correlation was found between age, height, or spirometric data and exhaled NO levels (r < 0.2). The mean value of nasal NO concentrations was 216 ppb (95% C.I., 204-228 ppb). There was no correlation between exhaled and nasal NO values (r = 0.16, P = ns). In conclusion, this study establishes a reference range for exhaled NO values measured by a tidal breathing method in children between age 6-15 years. The observed levels are independent of age, gender, and lung function, and can be used to monitor airway inflammation in asthmatic children.

Adolescent↗
PubMed1999

The balloon technique: a convenient method to measure exhaled NO in epidemiological studies.

OBJECTIVES: The aim of the present study was to evaluate the balloon procedure to measure exhaled nitric oxide (NO). METHODS: This was performed by comparing the procedure with the well-established on-line measurement of NO (direct exhalation into the NO module). Using both procedures exhaled NO was measured in 16 healthy subjects on two days with different level of air pollution. RESULTS: Exhaled NO measured on-line was 3.8-4.5 times lower than exhaled NO obtained using the balloon technique but the two sets of values correlated linearly (r 0.93-0.97). Mean NO level on day 1 with low air pollution and day 2 with high air pollution was 6.6 and 8.1 parts per billion (ppb; on-line measurement) and 25.2 and 36.9 ppb (balloon method), respectively. The day 1 to day 2 ratio differed per subject but was independent of the technique of measurement. Mean day-to-day ratio of exhaled NO using the balloon technique (1. 65 +/- 0.13) was not different (P < 0.05) from the ratio of NO levels measured on-line (1.49 +/- 0.13). Based on these ratios the increase in level of outdoor air pollution appears to be associated with a 49-65% increase in exhaled NO. CONCLUSION: Exhaled NO is proposed as a de novo individual biomarker to monitor the adverse effects of air pollution. The balloon procedure offers a sound and convenient alternative for the on-line procedure to measure exhaled NO in large populations as required in epidemiological studies.

Adult↗
PubMed2001

Mixed exhaled nitric oxide and plasma nitrites and nitrates in newborn infants.

Plasma nitrite (NO2-) and nitrate (NO3-) are the stable end-products of endogenous nitric oxide (NO) metabolism. NO is present in the exhaled air of humans, but it is not clear if exhaled NO may be an indicator of the systemic endogenous NO production. The aims of the study were to determine the levels of exhaled NO and plasma NO2-/NO3- in healthy term and preterm newborns, and to assess if exhaled NO correlates with plasma NO2-/NO3- at birth. After the stabilization of the newborn, we measured by chemiluminescence the concentration of NO in the mixed expired breath of 133 healthy newborns. Measurement of exhaled NO was repeated after 24 and 48 hours. Plasma NO2-/NO3- levels at birth were measured by the Griess reaction. NO concentrations were 8.9 (CI 8.1-9.8) parts per billion (ppb), 7.7 (CI 7.2-8.3) ppb and 9.0 (CI 8.4-9.6) ppb at birth, 24 and 48 hours, respectively. At birth, exhaled NO was inversely correlated with gestational age (p=0.008) and birth weight (p<0.001). Plasma NO2-/NO3- level was 27.30 (CI 24.26-30.34) micromol/L. There was no correlation between exhaled NO and plasma NO2-/NO3- levels at birth (p=0.88). We speculate that the inverse correlation between exhaled NO and gestational age and birth weight may reflect a role of NO in the postnatal adaptation of pulmonary circulation. At birth, exhaled NO does not correlate with plasma NO2-/NO3- and does not seem to be an index of the systemic endogenous NO production.

Birth Weight↗
PubMed1998

Improvement of CT-based treatment-planning models of abdominal targets using static exhale imaging.

PURPOSE: CT-based models of the patient that do not account for the motion of ventilation may not accurately predict the shape and position of critical abdominal structures. Respiratory gating technology for imaging and treatment is not yet widely available. The purpose of the current study is to explore an intermediate step to improve the veracity of the patient model and reduce the treated volume by acquiring the CT data with the patients holding their breath at normal exhale. METHODS AND MATERIALS: The ventilatory time courses of diaphragm movement for 15 patients (with no special breathing instructions) were measured using digitized movies from the fluoroscope during simulation. A subsequent clinical protocol was developed for treatment based on exhale CT models. CT scans (typically 3.5-mm slice thickness) were acquired at normal exhale using a spiral scanner. The scan volume was divided into two to three segments, to allow the patient to breathe in between. Margins were placed about intrahepatic target volumes based on the ventilatory excursion inferior to the target, and on only the reproducibility of exhale position superior to the target. RESULTS: The average patient's diaphragm remained within 25% of the range of ventilatory excursion from the average exhale position for 42% of the typical breathing cycle, and within 25% of the range from the average inhale position for 15% of the cycle. The reproducibility of exhale position over multiple breathing cycles was 0.9 mm (2sigma), as opposed to 2.6 mm for inhale. Combining the variation of exhale position and the uncertainty in diaphragm position from CT slices led to typical margins of 10 mm superior to the target, and 19 mm inferior to the target, compared to margins of 19 mm in both directions under our prior protocol of margins based on free-breathing CT studies. For a typical intrahepatic target, these smaller volumes resulted in a 3.6% reduction in Veff for the liver. Analysis of portal films shows proper target coverage for patients treated based on exhale modeled plans. CONCLUSIONS: Modeling abdominal treatments at exhale, while not realizing all the gains of gated treatments, provides an immediate reduction in the volume of normal tissue treated, and improved reliability of patient data for NTCP modeling, when compared to current "free breathing" CT models of patients.

Diaphragm↗
PubMed2001

Exhalation of H2O2 and thiobarbituric acid reactive substances (TBARs) by healthy subjects.

Enhanced exhalation of H2O2 and TBARs have been reported in various inflammatory lung diseases. This may reflect activated phagocytes influx and free radical generation in the airways. However, to apply these compounds as markers of oxidative stress it is necessary to understand factors influencing their exhalation in healthy subjects. We investigated the concentration of H2O2 and TBARs in expired breath condensate (EBC) of 58 healthy volunteers. EBC was collected seven times every 4 h during 24 h and three times every 7 d during 2 consecutive weeks. The H2O2 exhalation revealed diurnal variation with two-peak values 0.45 +/- 0.29 microM and 0.43 +/- 0.22 microM at 12:00 and 24:00 h. The lowest concentrations, 0.26 +/- 0.13 microM and 0.25 +/- 0.26 microM, were found at 20:00 and 8:00 h. Cigarette smokers exhaled about 2.4 times more H(2)O(2) than never smoked subjects. Moreover, in contrast to nonsmokers, cigarette smokers' H2O2 exhalation was stable over 2 week observation. The mean H2O2 concentration estimated over the whole 2 week period was higher in subjects above 40 years regardless of smoking habit, and it positively correlated with age in never smoked subjects (p <.004). Smoking of one cigarette caused 1.8-fold rise in H2O2 exhalation (p <.01). The baseline H2O2 levels correlated with cumulative cigarette consumption (p <.05) and MEF 25% of predicted (p <.05). Neither moderate exercise nor one puff of salbutamol nor ipratropium influenced significantly the concentration of H2O2 and TBARs in EBC. Only 4 of 120 EBC specimens from never smoked subjects revealed detectable levels of TBARs. Cigarette smokers exhaled more TBARs (p <.05) than never smoked volunteers. Our results indicate that healthy never smoked subjects exhale H2O2 with diurnal variation and significant changes over 2 week observation. Cigarette smoking enhanced H2O2 generation in the airways. These results could be useful for planning studies with exhaled H2O2 as a marker of airway inflammation. Occasional detection of TBARs in EBC of never smoked persons may be a result of sufficient antioxidant activity in the airways that protects tissues from peroxidative damage.

Adult↗
PubMed1999

Salivary contribution to exhaled nitric oxide.

Dietary and metabolic nitrate is distributed from the blood to the saliva by active uptake in the salivary glands, and is reduced to nitrite in the oral cavity by the action of certain bacteria. Since it has been reported that nitric oxide may be formed nonenzymatically from nitrite this study aimed to determine whether salivary nitrite could influence measurements of exhaled NO. Ten healthy subjects fasted overnight and ingested 400 mg potassium nitrate, equivalent to approximately 200 g spinach. Exhaled NO and nasal NO were regularly measured with a chemiluminescence technique up to 3 h after the ingestion. Measurements of exhaled NO were performed with a single-breath procedure, standardized to a 20-s exhalation, at a flow of 0.15 L x s(-1), and oral pressure of 8-10 cmH2O. Values of NO were registered as NO release rate (pmol x s(-1)) during the plateau of exhalation. Exhaled NO increased steadily over time after nitrate load and a maximum was seen at 120 min (77.0+/-15.2 versus 31.2+/-3.0 pmol x s(-1), p<0.01), whereas no increase was detected in nasal NO levels. Salivary nitrite concentrations increased in parallel; at 120 min there was a four-fold increase compared with baseline (1.56+/-0.44 versus 0.37+/-0.09 mM, p<0.05). The nitrite-reducing conditions in the oral cavity were also manipulated by the use of different mouthwash procedures. The antibacterial agent chlorhexidine acetate (0.2%) decreased NO release by almost 50% (p<0.01) 90 min after nitrate loading and reduced the preload control levels by close to 30% (p<0.05). Sodium bicarbonate (10%) also reduced exhaled NO levels, but to a somewhat lesser extent than chlorhexidine acetate. In conclusion, salivary nitric oxide formation contributes to nitric oxide in exhaled air and a large intake of nitrate-rich foods before the investigation might be misinterpreted as an elevated inflammatory activity in the airways. This potential source of error and the means for avoiding it should be considered in the development of a future standardized method for measurements of exhaled nitric oxide.

Adult↗
PubMed1999

Exhaled carbon monoxide levels during treatment of acute asthma.

Carbon monoxide is known to be present in measurable quantities in the exhaled air of normal subjects and at higher concentrations in asthmatic patients not treated with glucocorticoids. To examine whether exhaled CO is useful in monitoring asthma control, time course changes in peak expiratory flow rate (PEFR) and exhaled CO concentration before and after treatment of acute asthma exacerbations were measured in 20 asthmatic patients. Exhaled CO was measured in triplicate by a portable CO analyser. Exhaled CO was reproducible at all time points. Asthma exacerbations caused a fall in PEFR and a rise in exhaled CO (towards an average of 3.3 parts per million (ppm)) in all patients, and treatment with oral glucocorticoids reversed these changes in both parameters. An improvement of PEFR was closely associated with a reduction of exhaled CO (to an average of 1.5 ppm) after treatment. The maximal exhaled CO concentration significantly correlated with recovery time of PEFR after treatment with oral glucocorticoids (p<0.01). The present study suggests that exhaled CO may be a useful noninvasive means of monitoring the control of asthma.

Administration, Inhalation↗
PubMed2002

Dispersal of exhaled air and personal exposure in displacement ventilated rooms.

The influence of the human exhalation on flow fields, contaminant distributions, and personal exposure in displacement ventilated rooms is studied together with the effects of physical movement. Experiments are conducted in full-scale test rooms with life-sized breathing thermal manikins. Numerical simulations support the experiments. Air exhaled through the mouth can lock in a thermally stratified layer, if the vertical temperature gradient in breathing zone height is sufficiently large. With exhalation through the nose, exhaled air flows to the upper part of the room. The exhalation flow from both nose and mouth is able to penetrate the breathing zone of another person standing nearby. The stratification of exhaled air breaks down if there is physical movement in the room. As movement increases, the concentration distribution in the room will move towards a fully mixed situation. The protective effect of the boundary layer flow around the body of a moving person disappears at low speed, and is reduced for a seated person placed nearby due to horizontal air movements, which can also cause rebreathing of exhaled air for the seated person. The results indicate that the effect of the exhalation flow is no acute problem in most normal ventilation applications. However, exhalation and local effects caused by movement may be worth considering if one wishes to contain contaminants in certain areas, as in the case of tobacco smoking, in hospitals and clinics, or in certain industries.

Air Movements↗
PubMed2001

Nitric oxide (NO) in exhaled air after experimental ozone exposure in humans.

We hypothesized that ozone, a common air pollutant, potent in producing airway inflammation, would increase the production of exhaled nitric oxide (NO). If so, measurement of exhaled NO could potentially be a valuable tool in population studies of air pollution effects. Eleven healthy non-smoking volunteers were exposed to 0.2 ppm ozone (O3) and filtered air for 2h on two separate occasions. Exhaled NO and nasal NO were measured before and on five occasions following the exposures. Changes in exhaled and nasal NO after ozone exposure were adjusted for changes after air exposure. There was a slight decrease in exhaled NO (-0.6; -3.1-1.2 ppb) (median and 95% confidence interval) and of nasal NO (-57; -173-75 ppb) directly after the ozone exposure. No significant changes in exhaled or nasal NO were however found 6 or 24 h after the exposure. Within the examined group, an O3 exposure level proven to induce an airway inflammation caused no significant changes in exhaled or nasal NO levels. Hence, the current study did not yield support for exhaled NO as a useful marker of ozone-induced oxidative stress and airway inflammation after a single exposure. This contrasts with data for workers exposed to repeated high peaks of ozone. The potential for exhaled NO as a marker of oxidative stress therefore deserves to be further elucidated.

Adult↗
PubMed2002

Exhaled leukotrienes and prostaglandins in asthma.

BACKGROUND: Most of the studies investigating the role of leukotrienes (LTs) and prostaglandins (PGs) in asthma have used invasive (eg, bronchoalveolar lavage fluid) or semi-invasive (eg, sputum induction) techniques. Others have measured eicosanoids in plasma or urine, probably reflecting systemic rather than lung inflammation. Collection of exhaled breath condensate (EBC) is a noninvasive method to collect airway secretions. OBJECTIVE: We sought to investigate whether eicosanoids are measurable in EBC, to show possible differences in their concentrations in asthmatic patients and healthy subjects, and to investigate whether exhaled eicosanoids correlate with exhaled nitric oxide (NO), a marker of airway inflammation. METHODS: Twelve healthy nonsmokers and 15 steroid-naive patients with mild asthma were studied. Subjects attended on one occasion for pulmonary function tests, collection of EBC, and exhaled NO measurements. Exhaled LTB(4)-like immunoreactivity, LTE(4)-like immunoreactivity, PGE(2)-like immunoreactivity, PGD(2)-methoxime, PGF(2)(alpha)-like immunoreactivity, and thromboxane B(2)-like immunoreactivity were measured by means of enzyme immunoassays. RESULTS: LTE(4)-like immunoreactivity and LTB(4)-like immunoreactivity were detectable in EBC in healthy subjects, and their levels in asthmatic patients were increased about 3-fold (P <.0001) and 2-fold (P <.0005), respectively. Exhaled NO was increased in asthmatic patients compared with healthy subjects (P <.0001). There was a correlation between exhaled LTB(4) and exhaled NO (r = 0.56, P <.04) in patients with asthma. When measurable, prostanoid levels were similar in asthmatic patients and control subjects. CONCLUSIONS: Exhaled LTE(4) and LTB(4) are increased in steroid-naive patients with mild asthma. EBC may be proved to be a novel method to monitor airway inflammation in asthma.

Adult↗
PubMed1994

The effect of aging, humidity, and fly-ash additive on the radon exhalation from concrete.

Radon exhalation rates of concrete samples have been periodically determined for 6-8 y after pouring the concrete. From the results, it can be concluded that the radon exhalation rate changes with the age of the concrete. The exhalation rate varies considerably in the first 6-12 mo after pouring with a factor of 1.5. After this period, the variation in exhalation rates is much less. Starting 1 y after pouring, the radon exhalation rate was decreased with increasing age of concrete to 0.3-0.6 of the maximum at the end of the observed period. Low humidity conditions dramatically reduce the radon exhalation rate of concrete. If 25% by volume of the cement is replaced by fly ash, the 226Ra concentration is elevated by a factor of 1.5. The radon exhalation rate of concrete made with Portland cement and fly ash was increased only slightly or even decreased, despite the higher 226Ra content. The results indicate that measurements of radon exhalation from samples of concrete have to be standardized on a certain humidity and age of the sample. Under certain conditions, the addition of fly ash to the concrete can reduce the radon exhalation.

Air Pollutants, Radioactive↗
PubMed2005

The use of exhaled nitric oxide concentration to identify eosinophilic airway inflammation: an observational study in adults with asthma.

BACKGROUND: Assessment of eosinophilic airway inflammation may be helpful in the management of asthma. Nitric oxide (NO) has potential advantages as a tool to monitor airway inflammation although little is known about the relationship between NO and eosinophilic airway inflammation and the factors which influence it. METHODS: We set out to define the relationship between exhaled NO and the sputum eosinophil count, identify the exhaled NO concentration that best identified a sputum eosinophil count >3% and investigate the impact of several potential confounding factors in 566 consecutive patients with varying severity of asthma. Finally we examined the ability of exhaled NO concentrations measured at differing exhalation flows to identify the presence of a sputum eosinophilia. RESULTS: We found a significant positive relationship between exhaled NO and sputum eosinophil count (R(2)=0.26, P<0.001) which was best described using a non-linear model. There were no clinically important confounding factors to this model. In non-smokers an exhaled NO concentration of >8.3 p.p.b. at 250 mL/s gave 71% sensitivity and 72% specificity for identifying a sputum eosinophil count of >3%. CONCLUSIONS: This value of exhaled NO would seem to be the best for identifying significant eosinophilic airway inflammation. It is applicable to a wide range of non-smoking patients with asthma; exhalation flow does not alter the ability of exhaled NO concentration to detect a sputum eosinophilia.

Adolescent↗
PubMed2000

Increased nitric oxide in exhaled air: an early marker of asthma in non-smoking aluminium potroom workers?

OBJECTIVES: To study exhaled nitric oxide (NO) as a marker of airway inflammation caused by potroom exposure, hypothesising that (a) workers exposed to potroom pollutants would have higher concentrations of NO in expired air than control subjects employed at the same plant but working outside of the potroom atmosphere, and (b) that concentrations of exhaled NO in potroom employees might be positively associated with concentrations of fluoride and exposure to dust. METHODS: A study group comprising 186 male subjects (aged 24-63 years), employed in the potrooms of one Norwegian aluminium smelter, and 40 comparable control subjects (aged 25-60 years) recruited from the same plant, were examined by measurements of exhaled and nasal concentrations of NO, spirometry, and a questionnaire on respiratory symptoms as a part of an annual health surveillance programme. Estimates of exposure to fluorides and dust for selected job categories were obtained by means of personal samplers carried by the workers. RESULTS: In the non-smokers, the concentrations of exhaled NO were higher in the potroom workers than in the controls (median (interquartile range) 9.3 (6.2-15.6) v 5.7 (4.6-8.3) ppb, p=0.001). The two groups did not differ in spirometry and asthma-like symptoms. Non-smoking potroom workers with asthma-like symptoms had higher concentrations of exhaled NO than those with no symptoms (median (interquartile range) 21.0 (19.3-41. 4) v 8.5 (5.9-12.8) ppb, p=0.001), but had comparable spirometric values. In subjects who smoked, the concentrations of exhaled NO did not differ significantly between potroom workers and controls (median (interquartile range) 4.6 (3.3-8.0) v 4.0 (3.4-5.1) ppb. Exhaled NO was not significantly associated with either duration of employment or routine measurements of dust and fluorides. CONCLUSIONS: Exposure to potroom pollutants is associated with increased concentrations of exhaled NO in non-smoking subjects. Nitric oxide in exhaled air may be an early marker of airway inflammation in aluminium potroom workers.

Adult↗
PubMed1997

Decreased exhaled nitric oxide in subjects with HIV infection.

BACKGROUND: Nitric oxide (NO) may be an important component of the host defence against infections. Endogenously produced NO is present in exhaled air and may be representative of respiratory tract production of NO. Since subjects infected with HIV are prone to develop respiratory infections, it was postulated that exhaled NO might be reduced in such individuals. METHODS: The exhaled concentration of NO (nl/l) and minute ventilation (l/min) were measured and exhaled NO release (nl/min/m2) calculated in 36 subjects infected with HIV (20 non-smokers, 16 smokers) and 31 non-smoking subjects with no active medical conditions. RESULTS: Exhaled NO from HIV positive individuals was less than from control subjects of similar age, height, and weight. Cigarette smoking did not account for the decreased exhaled NO in HIV positive individuals as both smoking and non-smoking HIV positive subjects had decreased exhaled NO compared with control subjects. CONCLUSION: Exhaled NO is decreased in subjects infected with the HIV. Since NO functions in host defence against bacterial, viral, and fungal infections, reduced exhaled NO may indicate a mechanism of impaired host defence in HIV infection.

Adult↗