Airway smooth muscle tone is influenced by many hormones, neurotransmitters, drugs and mediators, which produce their effects by binding to specific surface receptors on airway smooth muscle cells. Bronchoconstriction and bronchodilatation may therefore be viewed in terms of receptor activation or blockade and the contractile state of airway smooth muscle is probably the resultant effect of int...

The aim of this study was to test the hypothesis that lung oedema causes an obstructive airway impairment, due to an increase in cholinergic bronchial tone in patients with chronic heart failure (CHF). Ten patients with CHF were tested by inhalation of ipratropium bromide and placebo, given in sequential randomized order, in double-blind fashion, after assessment of baseline lung function, both...

Droperidol has been reported to cause bronchodilatation but its mechanism(s) of action is unknown. We have evaluated the spasmolytic effect of droperidol on histamine- and serotonin (5-HT)-induced bronchoconstriction in dogs. Bronchial cross-sectional area was assessed with a superfine fibreoptic bronchoscope. Twenty-eight mongrel dogs were allocated randomly to one of two groups (histamine and...

Vasoactive intestinal peptide causes bronchodilatation when given intravenously but is less effective in both animals and man when given by inhalation. This difference may be due to poor transit of the peptide across the bronchial epithelium. To test this hypothesis pulmonary clearance of radiolabelled vasoactive intestinal peptide was measured in Sprague Dawley rats and compared with that of p...

We investigated the relationship between airway calibre and the dose and distribution of inhaled aerosol in ten normal and six asthmatic subjects. Subjects inhaled saline aerosol containing 99mTcO4 delivered from a nebulizer connected to a dosimeter, and the lung fields were scanned with a gamma-camera. Right lung dose (RLD) was calculated as percentage of total dose. Intrapulmonary distributio...

BACKGROUND This paper presents a system for classification of asthma and chronic obstructive pulmonary disease (COPD) based on fuzzy rules and the trained neural network. METHODS Fuzzy rules and neural network parameters are defined according to Global Initiative for Asthma (GINA) and Global Initiative for chronic Obstructive Lung Disease (GOLD) guidelines. For neural network training more th...

We compared the effects of two histamine receptor blocking agents, chlorpheniramine (H1) and cimetidine (H2) on the airways of healthy and asthmatic subjects. Eleven healthy subjects and ten asthmatic patients underwent histamine aerosol challenge. A threshold dose (T) for response to histamine was determined for each subject using maximal expiratory flow rates on partial expiratory flow rates ...

The paradoxical bronchoconstriction observed with commercially available isotonic ipratropium bromide nebuliser solution (Atrovent) in patients with asthma results from an adverse reaction to the preservatives, benzalkonium chloride and ethylenediaminetetra-acetic acid (EDTA). The airway response to inhaled Atrovent and preservative free ipratropium bromide nebuliser solutions has been examined...

A double blind, placebo controlled compa-rison was made of the effects of nebulised ipratropium bromide (0O05 and 0-5 mg) and salbutamol (0-25 and 2-5 mg) on lung function and the airway response to hyperventilation in eight normal subjects. Both agents at both doses caused similar baseline bronchodilatation, confirming the presence of resting bronchomotor tone. The overall mean increases as pe...

PURPOSE Midazolam has been used clinically as a sedative and as an anaesthetic induction agent. However, the bronchodilating effects of midazolam have not been comprehensively evaluated. We sought to determine relaxant effects of midazolam on the airway. METHODS After our Animal Care Committee approved the study, eight mongrel dogs were anaesthetized with 30 mg.kg-1 pentobarbitone iv, and wer...