OBJECTIVES 22 workers, exposed to potassium aluminium tetrafluoride used as flux for soldering aluminium, were studied as clinical outpatients for symptoms of irritation of the nose, eye, skin, and airways. METHODS 16 volunteered for spirometry with methacholine provocation test including a test for small airways function by volume of trapped gas (VTG). RESULTS Median (range) latency time b...

Neurokinin (NK) A causes airway narrowing in patients with asthma through direct and indirect mechanisms. The effects of the inhaled glucocorticosteroid fluticasone propionate (FP) on the bronchial responsiveness to NKA and methacholine were studied. Patients (n=11) with mild asthma participated in a randomized, double-blind, placebo-controlled crossover trial. FP (500 microg b.i.d.) or matched...

We have examined the effect of prior bronchoconstriction on the bronchial responsiveness to inhaled histamine in nine normal subjects. The airway response to increasing concentrations of histamine aerosol was assessed by measurement of specific airways conductance (sGaw) in a body plethysmograph. The threshold provocative dose of histamine needed to cause a 35% fall in starting sGaw (PD35) and ...

RATIONALE Bronchial hyperresponsiveness (BHR) is an important, but not specific, asthma characteristic. OBJECTIVES We aimed to assess the predictive value of BHR tested by methacholine and exercise challenge at age 10 years for active asthma 6 years later. METHODS From a Norwegian birth cohort, 530 children underwent methacholine challenge and exercise-induced bronchoconstriction (EIB) test...

Increased production of superoxide anion may contribute to impaired bioactivity of endothelium-derived nitric oxide in hypertension. Ascorbic acid is capable of scavenging superoxide anion; however, experimental studies have shown that high physiological concentrations (.1 mmol/L) of ascorbic acid are required to prevent superoxide-mediated vascular dysfunction. To seek kinetic evidence that su...

Airway hyperresponsiveness to a spasmogenic challenge such as methacholine, and an increased baseline tone measured by the reversibility of airway obstruction with a bronchodilator, are two common features of asthma. However, whether the increased tone influences the degree of airway responsiveness to a spasmogen is unclear. Herein, we hypothesized that increased tone augments airway responsive...

We hypothesized that the size of the large airways is a determinant of bronchial responsiveness to inhaled methacholine. This was investigated by measuring the relationship of tracheal size and branching angle to the bronchoconstrictive response to methacholine, in 169 male construction insulators, aged 20-50 yrs, as part of a workforce-based, cross-sectional survey of respiratory health. Bronc...

Deep inspiration (DI) dilates normal airway precontracted with methacholine. The fact that this effect is diminished or absent in asthma could be explained by the presence of bronchial inflammation. The hypothesis was tested that DI induces more relaxation in methacholine induced bronchoconstriction-solely determined by the smooth muscle contraction-than in exercise induced bronchoconstriction,...

STUDY OBJECTIVE To determine the protective effect of salbutamol, 100 microg, inhaled by different devices (pressurized metered-dose inhaler [pMDI; Ventolin; GlaxoWellcome; Greenford, UK], pMDI + spacer [Volumatic; GlaxoWellcome], or breath-activated pMDI [Autohaler; 3M Pharmaceuticals; St. Paul, MN]) on bronchoconstriction induced by methacholine. DESIGN Randomized, double-blind, cross-over,...

BACKGROUND Methacholine-induced bronchoconstriction is associated with significant hypoxemia, which can be assessed noninvasively by transcutaneous oxygen tension and pulse oximetry. OBJECTIVES To assess the value of the monitoring of finger pulse oximetry during routine methacholine challenges in a clinical pulmonary function laboratory with regard to both safety and the possibility that a s...