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The rates of exercise-induced bronchospasm (EIB) have been investigated in Olympic winter-sport athletes. It appears that EIB occurs in 25% of elite winter sport athletes. The rate is highest in cross-country skiing and in general is more prevalent in female athletes in these sports than in males. An athlete can compete successfully at the international level, even with EIB.

Background: Inhaled magnesium (Mg) seemed to have a mild protective (nonbronchodilator) effect against histamine and methacholine. Inhaled sodium metabisulfite (MBS) causes bronchoconstriction in asthma through indirect mechanisms that involve sensory nerve stimulation, and it is extensively used to study airway hyperresponsiveness. We designed this double-blind, randomized, crossover, and placebo-controlled study to test the effect of nebulized Mg sulfate against indirect challenge with MBS. Methods: Ten asthmatic subjects (three male) aged 38.8 (3.29, SEM) years came on three occasions to perform MBS challenges 5 min after inhalation of either normal saline solution as placebo or Mg sulfate (4 mL; 286 mOsm). Doubling increasing concentrations of MBS were administered by continuous nebulization at tidal breathing during 1 min starting at 0.3 to 80 mg/mL until a [is greater than] 20% fall in [FEV.sub.1] ([PC.sub.20]) from post saline solution baseline value was achieved. [PC.sub.20] values were logarithmically transformed before analysis. Results: The mean baseline [FEV.sub.1] at control day was 2.52 (0.14) L and 88.46 (4.28) percentage predicted, while the geometric mean MBS [PC.sub.20] was 1.95 (1.38, geometric SEM) mg/mL. After placebo, the geometric mean [PC.sub.20] was 2.26 (1.26) mg/mL. Inhaled Mg increased significantly the [PC.sub.20] to 5.06 (1.52) mg/mL; p[is less than] 0.05. Mg diminished the bronchoconstrictor response to MBS by 1.3 doubling doses (p=0.08). Conclusions: Inhaled Mg attenuates MBS-induced bronchoconstriction in these asthmatic subjects. This new feature of Mg, even modest in magnitude, emphasizes the necessity of studying the potential role of this cation in modulating airway response. (CHEST 1997;111:858-61) Key words: asthma; bronchoconstriction; magnesium; metabisulfite Abbreviations: DD=doubling dose; GSEM=geometric SEM; MBS=metabisulfite; Mg=magnesium; [PC.sub.20] =provocative concentration causing a 20% fall in [FEV.sub.1], Magnesium (Mg), the second most abundant intracellular cation,[1] has shown an in vitro relaxant effect on bronchial smooth muscle.[2] In the last decade, the potential role of IV Mg in [...]

We investigated whether the bronchodilator response to a β-adrenergic agonist is influenced by the mechanism of induced bronchoconstriction. Normal subjects and asymptomatic asthmatics inhaled a dry aerosol (mass median aerodynamic [...]

To compare the effects of posture on bronchial reactivity in 12 patients with mitral valve stenosis (MS) and 10 with bronchial asthma (BA), a methacholine inhalation test was performed 2 [...]

We examined the effect of pyridostigmine (PY) at a dose of 30 mg orally three times a day on nonspecific bronchial hyperreactivity in ten normal nonsmokers (NNS), ten smokers (SM), [...]

Exercise-induced bronchospasm (EIB) in children without asthma appears to occur more frequently in obese children than in those of normal weight. Symptoms of EIB include cough, chest tightness, difficulty breathing and easy fatigue. Of 27 children aged six to 10 with no history of asthma, 13 were obese and 14, who served as controls, were normal weight. Lung function was measured in all the children as they exercised on a treadmill for seven minutes. The average heart rate during exercise, which indicates exercise intensity, was similar for both groups. Nine of the obese children and six of the controls were found to have EIB. However, the degree of bronchial spasm was significantly worse among the obese children. Furthermore, EIB worsened as skin-fold thickness, which is a measure of obesity, increased. More research is necessary to determine whether having EIB increases children's risk of obesity by causing them to avoid aerobic exercise or whether obesity causes or worsens EIB.

Inhaled amiloride has been recently demonstrated to have an effect on the decline of pulmonary function in patients with cystic fibrosis. Other diuretics have been demonstrated to provide protection against [...]

Improvement of asthmatic symptoms was shown to be closely associated with a decrease in bronchial hypersensitivity to histamine inhalation. Thus, the patients' clinical backgrounds were compared between 26 long-term cases [...]

To determine the possible role of platelet-activating factor (PAF) in pulmonary embolism (PE), the reactivity of the airways to inhaled PAF, using doses ranging from 6.25 to 400 μg, was [...]

Epidemiologic data relating total circulating immunoglobulin E (IgE), an objective marker of allergy, to cross-sectional and longitudinal [FEV.sub.1] as well as to methacholine bronchial hyperresponsiveness were obtained from 310 French adult men surveyed five years apart. Skin prick test responses to common aeroallergens, IgE level, and bronchial hyperresponsiveness were assessed at the end of the follow-up. IgE level was not associated with PD20 to methacholine. Cross-sectionally, age and height-adjusted [FEV.sub.1] score was inversely related to total IgE level (regression coefficient of [FEV.sub.1] score on Log[IgE] β = -.20; p = 0.02). Stratified analysis showed that IgE level was associated with [FEV.sub.1] score only in nonsmokers (β = -0.52; p, Elevated total serum levels of immunoglobulin E (IgE), an objective marker of allergy, have been associated with a number of respiratory disorders,[1-3] as well as with impairment of cross-sectionally measured [...]

We evaluated bronchial responsiveness to inhaled albuterol (salbutamol), ipratropium bromide, methacholine, and propranolol in eight heart-lung transplant (HLT) recipients 2.3±1.5 months (mean ± SD) (range, 1 to 4.5 months) after [...]

The effect of caffeine on exercise-induced bronchoconstriction was examined in ten patients with bronchial asthma. Placebo and caffeine 3.5 mg/kg and 7 mg/kg were given two hours before exercise. Spirometry [...]

Cumulative dose response curves to inhaled methacholine were established in 24 'healthy' children of asthmatic parents and 7 healthy children of healthy parents. Atopic children of asthmatic parents demonstrated higher [...]

Study objective: To examine the baseline factors influencing the occurrence and magnitude of immediate- and late-phase responses in asthmatic patients after an allergen-induced bronchial provocation test (A-BPT). Design: Cross-sectional analysis [...]

Objectives: We administered aerosolized histamine to 32 subjects with tetraplegia to determine whether there were differences in spirometric and/or lung volume parameters between responders and nonresponders. Results: Baseline pulmonary function [...]

Study objective: To examine the difference in the mechanisms of bronchial hyperresponsiveness (BHR) in nonatopic asthma and in atopic asthma, we studied bronchial reactivity against nonspecific stimuli in children with [...]

The interrelationships between vocal cord dysfunction and laryngeal hyperresponsiveness may have profound implications in the diagnosis and management of patients with difficult respiratory symptoms. The ability of land animals to [...]

Allan R. Glanville, M.B.B.S; Genevieve M. Gabb, M.B.B.S.; James Theodore, M.D., F.C.C.P.;([unkeyable]) and Eugene D. Robin, M.D.([unkeyable]) Heart-lung transplant (HLT) recipients characteristically display marked bronchial hyperresponsiveness (BHR) to inhaled methacholine, [...]