BACKGROUND The bronchoprotective effect of caffeine on histamine challenge testing (HCT) has been studied with equivocal results. Current guidelines for bronchoprovocation testing recommend exclusion of caffeine the day of testing. The effects of caffeine on methacholine challenge testing (MCT), now more commonly performed than histamine challenge, are unknown. METHODS Sixteen well-controlled...

STUDY OBJECTIVES Some patients with COPD present with significant reversibility of airflow limitation after receiving bronchodilation therapy. Leukotriene B(4) (LTB(4)) has been implicated in the pathophysiology of both COPD and asthma. We tested the hypothesis that COPD patients with airflow reversibility and asthmatic patients who smoke might have similar levels of LTB(4) in exhaled breath co...

Deep inspiration temporarily reduces induced airways obstruction in healthy subjects. This bronchodilatory effect of deep inspiration is impaired in asthma. Passive machine-assisted lung inflation may augment bronchodilation compared with an active deep inspiration in patients with asthma by either opening closed airways or by reducing fluid flux across the airway wall during deep inspiration, ...

The precise role of inhibitory nonadrenergic noncholinergic (iNANC) neurons and nitric oxide in airway hyperresponsiveness remains uncertain. The role of NO in the regulation of airway responsiveness was studied in anaesthetized and mechanically ventilated cats. To assess airway responsiveness, the changes in total pulmonary resistance (RL) produced by delivering serotonin aerosol to the airway...

While airways have some degree of baseline tone, the level and variability of this tone is not known. It is also unclear whether there is a difference in airway tone or in the variability of airway tone between asthmatic and healthy individuals. This study examined airway tone and intraindividual airway tone heterogeneity (variance of airway tone) in vivo in 19 individuals with asthma compared ...