Search results for "Adrenergic beta-Agonists"
showing 10 items of 36 documents
Beta-adrenergic stimulation enhances left ventricular diastolic performance in normal subjects.
1997
To determine the effects of beta-adrenergic stimulation on transmitral Doppler echocardiography flow characteristics of left ventricular diastolic filling, we studied 10 healthy volunteers aged 23-31 years (mean age, 26.6 years) during intravenous infusion of isoprenaline in consecutive steps of 0.1, 0.2, 0.4, 0.75, and 1.5 micrograms/min (each for 15 min). Saline control infusion was given in the same manner in a crossover and blinded protocol. Compared with the infusion of placebo, stepwise increasing doses of isoprenaline caused a dose-related increase in early and late diastolic filling velocities and velocity-time integrals, a lengthening of the acceleration time, and a shortening of t…
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…
Measurement of inflammatory mediators of eosinophils and lymphocytes in blood in acute asthma: serum levels of ECP influence the bronchodilator respo…
2002
The aim of this study was to assess the relevance of immunoinflammatory markers on the response to short acting β<sub>2</sub>-agonist in acute asthma exacerbation. Thus, we measured serum eosinophil cationic protein (ECP) levels and sIL-2R at acute exacerbation in 52 adult patients with atopic asthma, and assessed forced expiratory volume in 1 s (FEV<sub>1</sub>) before and after the administration of aerosolized salbutamol. After a cumulative dose of salbutamol causing a 10% improvement in FEV<sub>1</sub> from baseline [CD10, i.e. cumulative doses of salbutamol (800 µg) causing an improvement in FEV<sub>1</sub> from baseline to 10%] the patie…
Sources of human plasma cyclic AMP. Examinations before and after beta 2 adrenergic stimulation.
1981
Plasma cyclic AMP was measured in different vessels in seventeen volunteers before and after stimulation with terbutaline. Differences between arterial blood and blood from the hepatic vein, right ventricle, inferior vena cava and a cubital vein could not be demonstrated. Only in the renal vein was the concentration of cyclic AMP decreased. Our results indicate that cyclic AMP is not generated from any specific isolated organ and that changes in cyclic AMP after subcutaneous injection of terbutaline reflect a general influence of this drug.
Relaxation by β3-adrenoceptor agonists of the isolated human internal anal sphincter
2009
In this study, responses of beta(3)-adrenoceptor agonists were examined on human isolated internal anal sphincter (IAS) in order to explore their relaxant effects on hypertonicity of IAS.The relaxant efficacy (E(max)) and potency (-logIC(50)) of BRL37344 and SR58611A, beta(3)-adrenoceptor agonists, were examined in contracted IAS muscle strips. The presence of beta(3)-adrenoceptors, and changes in intracellular calcium and cyclic nucleotide levels in IAS muscle were tested by Western blotting, epifluorescence microscopy and enzyme immunoassay, respectively.BRL37344 and SR58611A relaxed contracted IAS muscle (E(max)=27+/-3% and 35+/-3%; -logIC(50)=6.26+/-0.24 and 4.87+/-0.13; respectively). …
Prognostic Value of a Comprehensive Cardiac Magnetic Resonance Assessment Soon After a First ST-Segment Elevation Myocardial Infarction
2009
ObjectivesTo evaluate the prognostic value of a comprehensive cardiac magnetic resonance (CMR) assessment soon after a first ST-segment elevation myocardial infarction (STEMI).BackgroundCMR allows for a simultaneous assessment of wall motion abnormalities (WMA), WMA with low-dose dobutamine (WMA-dobutamine), microvascular obstruction, and transmural necrosis. This approach has been proven to be useful to predict late systolic recovery soon after STEMI. Its prognostic value and the relative prognostic weight of these indexes are not well-defined.MethodsWe studied 214 consecutive patients with a first STEMI treated with thrombolytic therapy or primary angioplasty discharged from hospital. In …
Synthesis and pharmacological characterization of beta2-adrenergic agonist enantiomers: zilpaterol.
2009
The beta-adrenergic agonist 1 (zilpaterol) is used as production enhancer in cattle. Binding experiments of separated enantiomers on recombinant human beta(2)-adrenergic and mu-opioid receptors and functional studies showed that the (-)-1 enantiomer accounts for essentially all the beta(2)-adrenergic agonist activity and that it exhibits less affinity toward the mu-opioid receptor than (+)-1, which is a mu-opioid receptor antagonist. X-ray crystallography revealed the absolute configuration of (-)-1 to be 6R,7R.
Development and validation of a liquid chromatography tandem mass spectrometry method for the analysis of beta-agonists in animal feed and drinking w…
2010
A reproducible, sensitive and selective multiresidue analytical method for seven beta-agonists: clenbuterol (CBT), clenpenterol (CPT), ractopamine (RTP), brombuterol (BBT), mabuterol (MBT), mapenterol (MPT), and hydroxymethylclenbuterol (HMCBT) was developed and validated by using liquid chromatography tandem mass spectrometry (LC-MS/MS) in feed and drinking water samples. The validation was achieved according to the criteria laid down in the Commission Decision 2002/657/EC, however it was necessary to use minimum required performance limits (MRPLs) proposed by the Community Reference Laboratories (CRLs) due to the lack of maximum residue limits (MRLs) for beta-agonists. By setting up these…
Simultaneous stimulation of GABA and beta adrenergic receptors stabilizes isotypes of activated adenylyl cyclase heterocomplex
2004
Abstract Background We investigated how the synthesis of cAMP, stimulated by isoproterenol acting through β-adrenoreceptors and Gs, is strongly amplified by simultaneous incubation with baclofen. Baclofen is an agonist of δ-aminobutyric acid type B receptors [GABAB], known to inhibit adenylyl cyclase via Gi. Because these agents have opposite effects on cAMP levels, the unexpected increase in cAMP synthesis when they are applied simultaneously has been intensively investigated. From previous reports, it appears that cyclase type II contributes most significantly to this phenomenon. Results We found that simultaneous application of isoproterenol and baclofen specifically influences the assoc…
Budesonide/formoterol maintenance and reliever therapy: a new treatment approach for adult patients with asthma.
2007
An inhaled corticosteroid (ICS) or an ICS/long-acting beta(2)-agonist (LABA) combination plus short-acting beta(2)-agonist (SABA) as needed for symptom relief is recommended for persistent asthma. Additionally, budesonide/formoterol maintenance and reliever therapy (Symbicort SMART, AstraZeneca, Sweden) has been approved for adults in the European Union. This option is well tolerated and offers greater reductions in asthma exacerbations together with similar improvements in daily symptom control, at a lower overall steroid load, compared with fixed-dose ICS/LABA plus SABA.Two large clinical trials investigated the use of budesonide/formoterol as maintenance and reliever compared with medium…