Comparison of exhaled breath condensate pH using two commercially available devices in healthy controls, asthma and COPD patients

<p>Abstract</p> <p>Background</p> <p>Analysis of exhaled breath condensate (EBC) is a non-invasive method for studying the acidity (pH) of airway secretions in patients with inflammatory lung diseases.</p> <p>Aim</p> <p>To assess the reproducibility of EBC pH for two commercially available devices (portable RTube and non-portable ECoScreen) in healthy controls, patients with asthma or COPD, and subjects suffering from an acute cold with lower-airway symptoms. In addition, we assessed the repeatability in healthy controls.</p> <p>Methods</p> <p>EBC was collected from 40 subjects (n = 10 in each of the above groups) using RTube and ECoScreen. EBC was collected from controls on two separate occasions within 5 days. pH in EBC was assessed after degasification with argon for 20 min.</p> <p>Results</p> <p>In controls, pH-measurements in EBC collected by RTube or ECoScreen showed no significant difference between devices (p = 0.754) or between days (repeatability coefficient RTube: 0.47; ECoScreen: 0.42) of collection. A comparison between EBC pH collected by the two devices in asthma, COPD and cold patients also showed good reproducibility. No differences in pH values were observed between controls (mean pH 8.27; RTube) and patients with COPD (pH 7.97) or asthma (pH 8.20), but lower values were found using both devices in patients with a cold (pH 7.56; RTube, p < 0.01; ECoScreen, p < 0.05).</p> <p>Conclusion</p> <p>We conclude that pH measurements in EBC collected by RTube and ECoScreen are repeatable and reproducible in healthy controls, and are reproducible and comparable in healthy controls, COPD and asthma patients, and subjects with a common cold.</p

Contribution of Cell Elongation to the Biofilm Formation of Pseudomonas aeruginosa during Anaerobic Respiration

Pseudomonas aeruginosa, a gram-negative bacterium of clinical importance, forms more robust biofilm during anaerobic respiration, a mode of growth presumed to occur in abnormally thickened mucus layer lining the cystic fibrosis (CF) patient airway. However, molecular basis behind this anaerobiosis-triggered robust biofilm formation is not clearly defined yet. Here, we identified a morphological change naturally accompanied by anaerobic respiration in P. aeruginosa and investigated its effect on the biofilm formation in vitro. A standard laboratory strain, PAO1 was highly elongated during anaerobic respiration compared with bacteria grown aerobically. Microscopic analysis demonstrated that cell elongation likely occurred as a consequence of defective cell division. Cell elongation was dependent on the presence of nitrite reductase (NIR) that reduces nitrite (NO2−) to nitric oxide (NO) and was repressed in PAO1 in the presence of carboxy-PTIO, a NO antagonist, demonstrating that cell elongation involves a process to respond to NO, a spontaneous byproduct of the anaerobic respiration. Importantly, the non-elongated NIR-deficient mutant failed to form biofilm, while a mutant of nitrate reductase (NAR) and wild type PAO1, both of which were highly elongated, formed robust biofilm. Taken together, our data reveal a role of previously undescribed cell biological event in P. aeruginosa biofilm formation and suggest NIR as a key player involved in such process

Invasive pneumococcal disease in a cohort of predominantly HIV-1 infected female sex-workers in Nairobi, Kenya

BACKGROUND: HIV infection is a major risk factor for pneumococcal disease in industrialised countries. Although both are common infections in sub-Saharan Africa, few studies have investigated the importance of this interaction. We have followed up a cohort of female sex-workers in Nairobi and report here on the extent of invasive pneumococcal disease. METHODS: A well-established cohort of low-class female sex-workers, based around a community clinic, was followed up from October, 1989, to September, 1992. 587 participants were HIV positive and 132 remained HIV negative. Set protocols were used to investigate common presentations. Cases were identified clinically and radiographically. Streptococcus pneumoniae and other pathogens were diagnosed by culture. FINDINGS: Seventy-nine episodes of invasive pneumococcal disease were seen in the 587 HIV-positive women compared with one episode in the 132 seronegative women (relative risk 17.8, 95% CI 2.5 to 126.5). In seropositive women the incidence rate was 42.5 per 1000 person-years and the recurrence rate was 264 per 1000 person-years. By serotyping, most recurrent events were re-infection. A wide spectrum of HIV-related pneumococcal disease was seen: only 56% of cases were pneumonia; sinusitis was seen in 30% of cases, and occult bacteraemia, a novel adult presentation, in 11%. Despite forty-two bacteraemic episodes, no deaths were attributable to Strep pneumoniae. At first presentation the mean CD4 cell count was 302/microL(SD 191) and was 171/microL (105) for recurrent episodes. During acute Strep pneumoniae infection the CD4 cell count was reversibly suppressed (mean fall in sixteen episodes, 105/microL [123]). The neutrophil response to acute infection was blunted and was correlated with CD4 count (r=0.50, 95% CI 0.29 to 0.66). Strep pneumoniae caused more disease, at an earlier stage of HIV immunosuppression, than Mycobacterium tuberculosis or non-typhi salmonellae. INTERPRETATION: Our study highlights the importance of the pneumococcus as an early but readily treatable complication of HIV infection in sub-Saharan Africa

Association between smoking and respiratory function before and after menopause

There is a lack of evidence about whether menopausal status influences the effect of smoking on lung function. This study examined the association between smoking and menopausal status and lung function independent of each other. Data were from a cohort of women attending the 21-year follow-up of the Mater University of Queensland Study of Pregnancy. The study was based on 2020 women who provided data on respiratory function, smoking, and menopausal status. A Spirobank G spirometer system was used to measure forced vital capacity (FVC), forced expiratory volume in first second (FEV(1)), and forced expiratory flow between 25 and 75% of forced vital capacity (FEF(25-75)). Smoking and menopausal status were assessed by self-report. Respiratory function was associated with cigarette smoking, menopausal status, and hormone replacement therapy. Regardless of smoking status, postmenopausal women had poorer lung function when compared with premenopausal women. In multivariate analysis, cigarette smoking was associated with lower FVC, FEV(1), and FEF(25-75), with the magnitude of effect being stronger for women who were postmenopausal. The data suggest that the impact of smoking intensifies after menopause. It seems plausible that effective quit-smoking programs, particularly after menopause, may lead to better lung function and reduced morbidity and mortality in women