Bronchoconstriction and hypoxemia have been reported to occur during airway challenges, but the correlation between changes in forced expiratory volume in 1 s (FEV1) and transcutaneous oxygen partial pressure (tcPO2) during methacholine provocation tests has not yet been established (to our knowledge). In 15 symptom-free atopic asthmatic patients and 5 normal subjects, variations in tcPO2 and F...

The regulation of the muscarinic receptor by the agonist methacholine was investigated in the perfused working rat heart. After 2.5 hr of perfusion with 4 microM methacholine, the number of (-)-[3H]-quinuclidinyl benzilate binding sites was significantly reduced (10-18%) in the right and left atria and left ventricle when compared with controls (2.5 hr of perfusion in the absence of methacholin...

BACKGROUND The effect of cessation of exposure to pollen on the concentration-response curves to inhaled methacholine was investigated. METHODS Methacholine inhalation challenges (up to 200 mg/ml) were performed in 13 non-asthmatic patients with grass and/or Parietaria pollen-induced rhinitis during the pollen season, and one and four months after it. Concentration-response curves were charac...

The mechanism by which leukotriene D4 (LTD4) induces airway narrowing in man is unclear. We have investigated this by examining the effect of the calcium channel blocker verapamil on the sensitivity of in vitro preparations of human bronchi to LTD4 and methacholine, and on the bronchoconstriction induced in normal subjects by these agonists in vivo. In vitro smooth muscle sensitivity was assess...

Nasal provocation tests with histamine and methacholine were carried out on 25 healthy men in an effort to assess the dynamic changes of albumin, total IgA, secretory IgA and lactoferrin concentrations in the nasal secretion. The trials were performed with 0.5, 1, and 4 mg of histamine and 8, 16, and 32 mg of methacholine. Each dose of histamine or methacholine was sprayed into the nose every 2...

PURPOSE The aim of this study was to investigate bronchodilator responsiveness (BDR) following methacholine-induced bronchoconstriction and to determine differences in BDR according to clinical parameters in children with asthma. METHODS The methacholine challenge test was performed in 145 children with mild to moderate asthma, and the provocative concentration causing a 20% decline in FEV1 (...

Submucosal glands secrete macromolecules and liquid that are essential for normal airway function. To determine the mechanisms responsible for airway gland secretion and the interaction between gland secretion and epithelial ion transport, studies were performed in porcine tracheal epithelia by using the hillocks and Ussing techniques. No significant baseline gland fluid flux (J(G)) was measure...

BACKGROUND Exposure to ammonium persulfate (AP) has been reported to be the main cause of occupational asthma in hairdressers. The aim of this study is to assess how long the asthmatic response to AP can be induced after dermal sensitization in a mouse model. METHODS BALB/c mice received dermal applications of AP or dimethylsulfoxide (DMSO) (control) on days 1 and 8. They then received a sing...

BACKGROUND Regular, inhaled beta 2 agonists may increase airway responsiveness in asthmatic subjects. The mechanism is not known but may be via an increase in airway inflammation. A study was undertaken to examine the effect of regular inhaled salbutamol on airway responsiveness to methacholine and hypertonic saline, on the maximal response plateau to methacholine, and on inflammatory cells in ...

BACKGROUND It has been suggested that health related job selection is a major cause of the healthy worker effect, and may result in inaccurate estimates of health risks of exposures in the working environment. Improved understanding of self selection, including the role of airway hyperresponsiveness, should improve accuracy in estimating occupational risks. METHODS We evaluated symptoms of th...