BACKGROUND The distribution of airway responsiveness in a general population of non-smokers without respiratory symptoms has not been established, limiting its use in clinical and epidemiological practice. We derived reference equations depending on individual characteristics (i.e., sex, age, baseline lung function) for relevant percentiles of the methacholine two-point dose-response slope. M...

BACKGROUND The diagnosis of occupational asthma (OA) can be challenging and needs a stepwise approach. However, the predictive value of the methacholine challenge has never been addressed specifically in this context. OBJECTIVE We sought to evaluate the sensitivity, specificity, and positive and negative predictive values of the methacholine challenge in OA. METHODS A Canadian database was ...

Isocyanates are the most significant cause of occupational asthma in our country. To evaluate the prevalence of work-related respiratory symptoms and immunologic sensitization to it, we performed a questionnaire survey, allergy skin test, radioallergosorbent test (RAST) to toluene diisocyanate (TDI)-human serum albumin (HSA) conjugate and methacholine bronchial challenge test on 23 isocyanate-e...

Exercise induced asthma (EIA) is a transient increase in airway resistance after intensive exercise and can be measured as a decline in forced expiratory volume in one second (FEV1). The condition is due to increased training load and inhalation of cold and dry air. Several studies have shown that eucapnic voluntary hyperpnea challenge test (EVH test) is a very sensitive and specific diagnostic...

Bronchial reactivity is being measured with increasing frequency in epidemiological studies, but there debate continues about the relative merits of the different methods used to measure reactivity, particularly for subjects with no previous experience of reactivity testing as is the case in epidemiological studies. Repeatability is likely to improve with practice, and laboratory based studies ...

Muscarinic receptor subtypes have been identified on airways of several mammalian species, including humans. M1-receptors are found in airway ganglia, M2-receptors (autoreceptors) are present in cholinergic postganglionic nerves at the prejunctional level, whereas the muscarinic receptor subtypes found in airway smooth muscle are of the M3-receptor subtype (1, 12). Methacholine 2-(acetyloxy)-N,...