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Individuals with human immunodeficiency virus (HIV) represent a population that is at a higher risk of developing chronic obstructive pulmonary disease (COPD). In this study, we sought to determine the effects of smoking on respiratory symptoms and diseases among HIV-positive patients and to determine if symptomatic patients are being appropriately screened for COPD. HIV-positive individuals completed a self-administered questionnaire. The effects of smoking on respiratory symptoms and diseases were reported as odds ratios (ORs). The COPD screening criteria were adapted from the Canadian Thoracic Society (CTS) guidelines. Two hundred and forty-seven participants were recruited. The median age was 49 years; 75% were male and 92% were on highly active antiretroviral therapy. Smokers represented 66% of the population. Smoking had a statistically significant effect on respiratory symptoms including wheeze (OR 4.8 [95% confidence interval (CI) 1.6-14.2]), phlegm production (OR 4.9 [95% CI: 2.2-10.5]), cough (OR 7.0 [95% CI: 3.0-16.2]), and dyspnea (OR 7.2 [95% CI: 1.7-31.2]). Smoking had a higher odds of respiratory diseases including COPD (OR 4.9 [95% CI: 1.1-21.9]) and bronchitis (OR 3.8 [95% CI: 1.9-7.7]). Among HIV-positive smokers, 40% met the CTS screening criteria, while only 12% self-reported a diagnosis of COPD. The burden of smoking in the HIV population is significant. HIV-positive smokers are more likely to report both respiratory symptoms and diseases than HIV-positive non-smokers. A discrepancy exists between patients who met the CTS screening criteria and those who were diagnosed with COPD, raising the concern for under-recognition and under-diagnosis of COPD in this population. [ABSTRACT FROM AUTHOR]

The aim of the present study was to investigate the relation between bronchoconstriction and cough induced by methacholine (Mch) inhalation and to elucidate the role of C-fibers and rapidly adapting irritant receptors (RARs) in these reactions in conscious guinea pigs. The authors measured enhanced pause (Penh) as an index of bronchoconstriction and also measured the number of coughs induced by Mch inhalation in conscious guinea pigs. The authors also examined the effects of pretreatment with procaterol, capsaicin desensitization and moguisteine on these responses. There was a significant positive correlation between the increase in Penh and the number of coughs induced by Mch inhalation. Procaterol (0.1 mg/kg, intraperitoneal [i.p.]) completely abolished both the Mch-induced increase in Penh and cough. Capsaicin desensitization had no effect on Penh or the number of coughs. Moguisteine (0.02, 0.2, or 2 mg/kg, i.p.) dose-dependently inhibited the number of coughs but not the increase in Penh induced by Mch inhalation. Bronchoconstriction causes cough via RARs, but not C-fibers. Neither RARs nor C-fibers are involved in Mch-induced bronchoconstriction itself. [ABSTRACT FROM AUTHOR]

TRPV1 is a modulator of noxious stimuli known to be important in the cough reflex. We have compared the expression of TRPV1 in normal human airways and those from patients with chronic cough and found that there is up regulation in airways smooth muscle in disease. This increased expression appears to be intracellular and we have therefore examined the role of intracellular rat and human TRPV1 activity was found using intracellular calcium signalling with human intracellular TRPV1 being located in a thapsigargin insensitive compartment. Increase in TRPV1 activity may have a role in the airway hypersensitivity seen in chronic cough. [ABSTRACT FROM AUTHOR]