The effects of a therapeutic serum theophylline concentration on inhaled methacholine and histamine were studied in 8 stable, moderately severe asthmatic children 8 to 15 yr of age. Placebo or theophylline in a hydroalcoholic solution was administered in a double-blind fashion, and standard histamine and methacholine challenges were performed following both placebo and theophylline. Serum theophylline concentration averaged 13 mg/L (range 4.0 to 22.1). Theophylline caused a significant increase (p less than 0.01, paired t test) in provocative dose for a 20% drop in FEV1 (PD20 FEV1) for both methacholine (from a mean of 19.1 to 57.5) and histamine (75.9 to 144.5). This effect did not correlate with the small (7.6% increase in FEV1) but significant bronchodilatation produced by theophylline. We conclude that theophylline in doses that achieve serum concentrations in the usual therapeutic range produces significant attenuation of the bronchoconstrictor response to methacholine and histamine challenges in asthmatic children. The mechanism and therapeutic implications of this remain undefined.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1164/arrd.1984.130.2.193 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Beta-adrenergic receptor stimulation, histamine receptor inhibition, and potassium channel opening contribute to the relaxant effects of crocetin on airway smooth muscle.
Iran J Basic Med Sci
January 2024
Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
Objectives: In the present study, the relaxant effect of crocetin on tracheal smooth muscle cells (TSM) and its possible mechanisms were evaluated.
Materials And Methods: The study was conducted on 54 male Wistar rats in 8 groups. TSM was contracted by methacholine (10 μM) and KCl (60 mM), and the relaxant effects of four cumulative concentrations of crocetin, petal extract of saffron, and theophylline were examined on non-incubated and TSM incubated with propranolol, chlorpheniramine, diltiazem, atropine, glibenclamide, and indomethacin were investigated.
The Fractional exhaled Nitric Oxide (FeNO)- test as add-on test in the diagnostic work-up of asthma: a study protocol.
BMC Pulm Med
April 2024
Department of Pulmonary Diseases, Center of Excellence for asthma, COPD and respiratory allergy, Franciscus Gasthuis & Vlietland, P.O. box 3045 PM, Rotterdam, The Netherlands.
Background: Asthma is a common disease characterized by chronic inflammation of the lower airways, bronchial hyperactivity, and (reversible) airway obstruction. The Global Initiative of Asthma Guideline recommends a flowchart to diagnose asthma with first-step spirometry with reversibility and a bronchial challenge test (BPT) with histamine or methacholine as a second step [1]. The BPT is considered burdensome, time-consuming for patients and staff, can cause side effects, and is expensive.
View Article and Find Full Text PDFDownregulation of protein phosphatase 2Aα in asthmatic airway smooth muscle.
Am J Physiol Lung Cell Mol Physiol
May 2024
Department of Pharmaceutical Sciences, North Dakota State University, Fargo, North Dakota, United States.
Airway smooth muscle cell (ASM) is renowned for its involvement in airway hyperresponsiveness through impaired ASM relaxation and bronchoconstriction in asthma, which poses a significant challenge in the field. Recent studies have explored different targets in ASM to alleviate airway hyperresponsiveness, however, a sizeable portion of patients with asthma still experience poor control. In our study, we explored protein phosphatase 2 A (PP2A) in ASM as it has been reported to regulate cellular contractility by controlling intracellular calcium ([Ca]), ion channels, and respective regulatory proteins.
View Article and Find Full Text PDFAirway hyperresponsiveness in asthma: The role of the epithelium.
J Allergy Clin Immunol
May 2024
Department of Respiratory Sciences, Leicester Respiratory National Institute for Health and Care Research Biomedical Research Centre, Glenfield Hospital, University of Leicester, Leicester, United Kingdom. Electronic address:
Airway hyperresponsiveness (AHR) is a key clinical feature of asthma. The presence of AHR in people with asthma provides the substrate for bronchoconstriction in response to numerous diverse stimuli, contributing to airflow limitation and symptoms including breathlessness, wheeze, and chest tightness. Dysfunctional airway smooth muscle significantly contributes to AHR and is displayed as increased sensitivity to direct pharmacologic bronchoconstrictor stimuli, such as inhaled histamine and methacholine (direct AHR), or to endogenous mediators released by activated airway cells such as mast cells (indirect AHR).
View Article and Find Full Text PDF[Standard technical specifications for methacholine chloride (Methacholine) bronchial challenge test (2023)].
Zhonghua Jie He He Hu Xi Za Zhi
February 2024
Article Synopsis
- The methacholine challenge test (MCT) is a key method for assessing airway hyperresponsiveness, particularly for diagnosing and treating bronchial asthma.
- A consensus group of experts in respiratory health has updated guidelines on MCT usage, focusing on common clinical issues, preparation, safety, and result interpretation.
- The updated guidelines specify who should undergo the MCT, outline absolute contraindications, and aim to assist healthcare practitioners in effectively using the test for patient assessment and treatment decisions.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!