Search results for "Bronchial provocation"
showing 10 items of 40 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…
Effects of allergen exposure on methacholine and AMP-induced air trapping in pollen-sensitive subjects
2011
Summary Background The effect of pro-inflammatory stimuli on bronchoconstrictor-induced air trapping has not been studied. Objective To determine the effect of natural allergen exposure, a pro-inflammatory stimulus, on methacholine- and adenosine 5′-monophospate (AMP)-induced air trapping. Methods Airway responsiveness to methacholine and AMP before and during the pollen season was obtained in 25 subjects with pollen allergy and in 10 healthy controls. The response was expressed by the sensitivity (PC 20 value) and by the slope and intercept of the FVC values recorded at each step of the challenge against the corresponding FEV 1 values. Results The slope and intercept FVC versus FEV 1 value…
Agreement in Asthmatics' Perception of Dyspnea During Acute and Chronic Obstruction
2005
Objective Three types of asthmatic patients can be identified during periods of clinical stability: “poor perceivers,” “normal perceivers,” and “over perceivers.” When asthmatics undergo bronchial challenge in the laboratory, the same distinctions in type of perception can be observed. The aim of the present study was to determine the level of agreement between the 2 situations. Patients and methods A total of 93 patients with persistent moderate asthma (36 men and 57 women; mean age 40 years) were studied. We asked them to assess their dyspnea on a modified Borg scale when stable and after each histamine dose in a bronchial provocation test. When a patient's Borg scale assessment in stable…
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 …
High-Resolution Computed Tomographic Evaluation of Airway Distensibility and the Effects of Lung Inflation on Airway Caliber in Healthy Subjects and …
2001
The effects of a deep inspiration (DI) in individuals with asthma differ from those observed in healthy subjects. It has been postulated that the beneficial effect of lung inflation is mediated by airway stretch. One hypothesis to explain the defects in the function of lung inflation in asthma is that a DI may be unable to stretch the airways. This may result from attenuation of the tethering forces between the airways and the surrounding parenchyma. In the current study, we used high-resolution computed tomography (HRCT) to examine the ability of a DI to distend the airways of subjects with asthma (n = 10) compared with healthy subjects (n = 9) at baseline and after increasing airway tone …
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 …
Exhaled Nitric Oxide Measurement Is Not Useful for Predicting the Response to Inhaled Corticosteroids in Subjects With Chronic Cough
2009
Background Increased concentrations of exhaled nitric oxide (ENO) are identified predominantly in subjects with chronic cough due to conditions that habitually respond well to therapy with inhaled corticosteroids (ICSs). The aim of this study was to assess the usefulness of ENO in predicting the response to ICS therapy in subjects with chronic cough and to determine the relationship between either methacholine or adenosine 5′-monophosphate (AMP) responsiveness and the response to ICS therapy. Methods A total of 43 patients with chronic cough were studied. During the baseline period, ENO measurement, spirometry, and concentration-response studies with both methacholine and AMP were performed…
The Lack of the Bronchoprotective and Not the Bronchodilatory Ability of Deep Inspiration Is Associated with Airway Hyperresponsiveness
2001
In healthy subjects, deep inspiration (DI) acts both as a bronchodilator and a bronchoprotector. The latter is impaired in asthmatics. We have now evaluated whether the lack of bronchoprotection is related to bronchial hyperresponsiveness (BHR), and whether the bronchodilatory effect is also lost in asthmatics. Ten healthy subjects (PC20 > 75 mg/ml), 12 asthmatics with moderate to severe BHR (PC20 < 1 mg/ml), 14 asthmatics with mild to borderline BHR (1 < PC20 < 25 mg/ml), and 10 rhinitics with mild to borderline BHR (1 < PC20 < 25 mg/ml) underwent single-dose methacholine provocations inducing at least 20% reduction in FEV1 after 20 min of DI inhibition. To measure the bronchodilatory effe…