Search results for "Bronchoconstrictor Agents"
showing 10 items of 19 documents
Bronchial reactivity and intracellular magnesium: a possible mechanism for the bronchodilating effects of magnesium in asthma
1998
1.Increased bronchial smooth muscle contractility with consequent bronchial hyperreactivity are characteristic physiopathological events of asthma. Since magnesium intervenes in calcium transport mechanisms and intracellular phosphorylation reactions, it constitutes an important determinant of the contraction/relaxation state of bronchial smooth muscle. In the present study we investigated the relationship between bronchial reactivity, assessed by methacholine-provocation test, and magnesium concentrations both at extracellular and intracellular levels measured by spectrophotometry. Twenty-two patients with mild-to-moderate asthma and 38 non-asthmatic subjects with allergic rhinitis (24 all…
Potent bronchoprotective effect of deep inspiration and its absence in asthma
2000
In the absence of deep inspirations, healthy individuals develop bronchoconstriction with methacholine inhalation. One hypothesis is that deep inspiration results in bronchodilation. In this study, we tested an alternative hypothesis, that deep inspiration acts as a bronchoprotector. Single-dose methacholine bronchoprovocations were performed after 20 min of deep breath inhibition, in nine healthy subjects and in eight asthmatics, to establish the dose that reduces forced expiratory volume in 1 s by >15%. The provocation was repeated with two and five deep inspirations preceding methacholine. Additional studies were carried out to assess optimization and reproducibility of the protocol …
Bronchoconstriction induced by inhaled adenosine 5′-monophosphate in subjects with allergic rhinitis
2001
Adenosine and its related nucleotide, adenosine 5′-monophosphate (AMP) induce bronchoconstriction in asthmatics, probably caused by histamine release from airway mast cells. The objective of this study was to determine the effect of inhaled AMP on lung function in subjects with allergic rhinitis.A total of 52 adults (28 subjects with allergic rhinitis, 14 asthmatics and 10 healthy subjects) were challenged with increasing concentrations of AMP and methacholine. Airflow was assessed after each concentration and the response to each bronchoconstrictor agent was measured by the provocative concentration required to produce a 20% fall (PC20) in forced expired volume in one second (FEV1).All 14 …
Airway Responsiveness to Inhaled Acetaldehyde in Subjects with Allergic Rhinitis: Relationship to Methacholine Responsiveness
2002
<i>Background:</i> Asthmatic subjects have an exaggerated airway response to inhaled acetaldehyde, but no information is available on airway responsiveness to this bronchoconstrictor agent in subjects with allergic rhinitis. <i>Objective:</i> The aim of this study was to determine the effect of inhaled acetaldehyde on lung function in nonasthmatic subjects with allergic rhinitis. <i>Methods:</i> A total of 78 adults (43 subjects with allergic rhinitis, 16 asthmatics and 19 healthy subjects) were challenged with increased concentrations of acetaldehyde and methacholine. The response to each bronchoconstrictor agent was measured by the provocative concentra…
Deep inspiration-induced changes in lung volume decrease with severity of asthma
2007
Summary We have previously reported that the magnitude of deep inspiration (DI)-induced bronchodilation is only slightly reduced in mild asthmatics, compared to healthy subjects. The aim of this study was to evaluate whether increased severity of asthma is associated with impairment in the ability of DI to induce changes in lung volume. Thirty-six consecutive asthmatics recruited from the Pulmonary and the Allergy Outpatient Clinics of the Institute of Respiratory Diseases of the University of Palermo were divided into 3 groups: Intermittent (I), Mild Persistent (MP) and Moderate–Severe (MS), based on GINA guidelines. Single dose methacholine (Mch) bronchoprovocations were performed in the …
Inhaled Corticosteroids and the Beneficial Effect of Deep Inspiration in Asthma
2005
Deep inspiration-induced bronchoprotection and bronchodilation are impaired in asthma. We evaluated the effect of inhaled glucocorticosteroids on these phenomena. Two groups of subjects with asthma, 9 with moderate/severe hyperresponsiveness to methacholine, and 12 with mild/borderline hyperresponsiveness to methacholine, received inhaled fluticasone (880 microg daily) for 12 weeks. Serial bronchoprovocations were performed at Weeks 0, 6, and 12. The impact of deep inspirations on the airway response to methacholine was evaluated on the basis of inspiratory vital capacity and FEV(1). Fluticasone produced a wide spectrum of changes in the beneficial effects of deep inspiration, but the mean …
The effect of challenge method on methacholine-induced changes in sensitivity and air trapping
2010
Summary Background The methacholine challenge test performed with the tidal breathing method induces a greater fall in FEV 1 than the dosimeter method; however, the effect of the challenge method on methacholine-induced fall in FVC has not been investigated. Objective To determine the influence of the challenge method on methacholine-induced changes in FEV 1 and FVC. Methods Airway responsiveness to methacholine was determined by dosimeter method and tidal breathing method in 37 subjects with suspected asthma. The dosimeter was modified to deliver an identical volume to that obtained with the tidal breathing method and the same nebulizer model was used for the two challenges. The response w…
Differences in sensitivity, maximal response and position of the concentration-response curve to methacholine between asthmatics, patients with aller…
1998
The aim of this study was to detect differences in maximal response and position of the concentration-response curves to methacholine between asthmatics and subjects with allergic rhinitis. A total of 228 adults (107 mild asthmatics, 96 allergic rhinitics and 25 healthy control subjects) were challenged with methacholine. The test was interrupted when FEV1 dropped by more than 40% or when the highest concentration of methacholine (200 mg ml-1) had been administered. Concentration-response curves were characterized by their PC20 (concentration of methacholine that produced 20% fall in FEV1 = airway sensitivity), and if possible, by their EC50 (concentration of methacholine that produced 50% …
Effects of exercise training on airway closure in asthmatics
2012
We previously reported that responsiveness to methacholine (Mch) in the absence of deep inspiration (DI) decreased in healthy subjects after a short course of exercise training. We assessed whether a similar beneficial effect of exercise on airway responsiveness could occur in asthmatics. Nine patients (male/female: 3/6; mean age ± SD: 24 ± 2 yr) with mild untreated asthma [forced expiratory volume in 1 s (FEV1): 100 ± 7.4% pred; FEV1/vital capacity (VC): 90 ± 6.5%] underwent a series of single-dose Mch bronchoprovocations in the absence of DI in the course of a 10-wk training rowing program (6 h/wk of submaximal and maximal exercise), at baseline ( week 0), and at week 5 and 10. The singl…
Urinary metabolites of histamine and leukotrienes before and after placebo-controlled challenge with ASA and food additives in chronic urticaria pati…
2002
Background: The recovery of mediator metabolites from urine has the potential to provide a rapid, safe, and easily available index of release of mediators. We aimed to determine urinary metabolites of both histamine and leukotrienes (LTs) in patients affected by chronic urticaria (CU). Methods: Twenty patients with CU were studied. They were selected on the basis of double-blind placebo-controlled challenge (DBPC) with acetyl salicylic acid (ASA) and food additives. Ten patients (group B) were negative to both challenges. Ten patients (group C) presented urticaria and/or the appearance of angioedema during or 24 h after challenge, with reactions to ASA (five patients) or food additives (fiv…