Search results for "Bronchodilatation"
showing 10 items of 17 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…
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 …
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…
Influence of low temperature on bronchodilatation induced by terbutaline administered by metered dose or dry powder inhalers in asthmatics.
2000
Low temperatures may affect dose delivery efficacy and clinical effectiveness of medication aerosols. In this study we examine the effect of cold ambient temperature on the bronchodilatation produced by terbutaline delivered from a chlorofluorocarbon pressurized metered dose inhaler (pMDI) compared to a multi-dose dry powder inhaler (DPI). Fourteen stable asthmatics were studied on two consecutive days. On day 1, after measuring FEV1 at room temperature (22 degrees C), each patient was randomized to receive 500 microg of terbutaline delivered from pMDI or DPI stored for 24 h at 22 degrees C with FEV1 recorded 20 min post-dose; then, patients were placed in a chamber at -10 degrees C, and af…
Investigation into isoprenaline resistance in patients with obstructive lung disease
1974
12 patients with chronic obstructive lung disease have been studied in an investigation regarding the causes of resistance to isoprenaline. The effects of repeated intravenous doses of 10 µg isoprenaline were assessed by cross over comparison before and after infusions of isoprenaline and a placebo; the infusions lasted for 35 to 40 min and the amount of isoprenaline infused was 0.5 µg/min. Total resistance, thoracic gas volume (whole-body plethysmography) and heart rate (ECG) were measured. No decrease in bronchospasmolytic or positive chronotopic effects on single isoprenaline injections could be demonstrated after prolonged infusions of isoprenaline.
Investigation into the role of phosphodiesterase IV in bronchorelaxation, including studies with human bronchus.
1993
1. We have investigated the role of cyclic nucleotide phosphodiesterase IV (PDE IV) in the relaxation of human bronchus and guinea-pig trachea in vitro and in guinea-pigs in vivo. 2. Functional studies showed that the selective PDE IV inhibitors, rolipram and denbufylline, relaxed human and guinea-pig preparations in vitro. 3. Two clinically used xanthine non-selective PDE inhibitors, theophylline and pentoxifylline, were also effective in these preparations, but were much less potent than the selective agents used. 4. The rank order of potency for the four PDE inhibitors in both species was similar. 5. Biochemical studies indicated that PDE IV was the major PDE isoform present in the human…
Bronchodilatory Effect of Deep Inspiration Is Absent in Subjects With Mild COPD
2004
Study objectives To investigate whether the bronchodilatory effect of deep inspiration is impaired in subjects with COPD. Methods We measured deep inspiration-induced bronchodilation in 19 patients with COPD and 17 healthy subjects (mean age, 67.8 ± 7.1 years vs 62.5 ± 9.3 years, respectively [± SEM]). Each subject underwent a series of single-dose methacholine provocations to induce at least a 15% reduction in inspiratory vital capacity (IVC). When this was achieved, subjects were asked to perform four consecutive deep inspirations, after which the IVC measurement was repeated and the percentage of bronchodilation by deep inspiration was calculated. Results The percentage of reduction in I…
Use of a portable device to record maximum inspiratory flow in relation to dyspnoea in patients with COPD
2011
SummaryForced inspiratory measures have been described to reflect the reduction in dyspnoea upon bronchodilation in severe COPD. Based on this we evaluated the applicability and usefulness of a portable device for the assessment of forced inspiration. In 37 patients with COPD (GOLD II/II/IV n = 16/15/6, mean ± SD FEV1 46.2 ± 15.4%pred) lung function was recorded prior to inhalation of 24 μg formoterol and 30 min later. Assessments comprised spirometry including forced inspiration, body plethysmography, maximum inspiratory flow (InCheck, Clement Clarke), and changes in dyspnoea via visual analogue scale (VAS). The sequence was repeated on a second day to assess reproducibility. Bronchodilati…
Oral Sustained-Release Aminophylline and Bronchodilator Response to Inhaled Fenoterol in Patients with Chronic Airflow Obstruction
1985
The bronchodilator response to inhaled fenoterol (400 micrograms) was examined in the morning and in the afternoon before and during oral sustained-release aminophylline treatment in eight patients with chronic reversible airway obstruction. Bronchodilatation was evaluated by measuring serial peak expiratory flow rates (PEFR) for eight hours after inhaled fenoterol and calculating the area under the time-response curves and the percentage increment from the baseline values. The patients showed an enhancement of the bronchodilatation achieved with fenoterol in the morning during aminophylline treatment. In the afternoon, instead, the effect of the fenoterol was not improved by oral aminophyl…
Lung function after acute and repeated exposures to extremely cold air (-110 degrees C) during whole-body cryotherapy.
2006
Whole-body cryotherapy (WBC) is one mode of cold therapy, during which rheumatic patients are exposed to very cold air (-110 degrees C) in minimal clothing. It is also proposed to have a bronchodilatory effect. The aim was to examine the effects of WBC on lung function in healthy humans after acute and repeated exposures. Twenty-five healthy, non-smoking subjects participated in the study. They were exposed to WBC for 2 min three times per week for 12 weeks. The peak expiratory flow rate (PEF) and forced expiratory volume in 1 s (FEV1) were measured before and after (at 2 and 30 min) the first WBC, and then similarly at 4, 8 and 12 weeks. At all time points, after 30 min of the WBC the PEF …