Search results for "Vasodilator"
showing 10 items of 128 documents
Regional perfusion and oxygenation of tumors upon methylxanthine derivative administration
1998
Abstract Purpose: The use of methylxanthine derivatives has been postulated as a means of increasing tumor perfusion and thus ameliorating tumor hypoxia. The aim of this study was to quantify and compare the effects of three methylxanthine derivatives: pentoxifylline (PX), torbafylline (TB), and HWA 138 (HW) on tumor perfusion and oxygenation. Methods and Materials: Anesthetized Sprague Dawley rats with DS-sarcomas implanted subcutaneously onto the hind foot dorsum were used in this study. Mean arterial blood pressure (MABP) was measured throughout experiments. Regional red blood cell (RBC) flux was monitored using a multichannel laser Doppler device and tumor oxygenation on a more global l…
Pulmonary vascular resistance as a potential marker of reactive pulmonary hypertension reduction following sildenafil therapy in patients disqualifie…
2019
Purpose:We sought to determine the predictors of restoration of heart transplantation (HTx) candidacy in pa-tients with systolic heart failure (HF) and reactive fixed pulmonary hypertension (RFPH) defined as pulmonaryvascular resistance (PVR) > 2.5 Wood units (WU), transpulmonary gradient (TPG) > 12 mmHg or ≤2.5 WUwith systolic arterial pressure ≤85 mmHg during vasoreactivity test, following sildenafil therapy.Material and methods:Between2007and20181136patientswereevaluatedatourdepartmentascandidatesforHTx. Thirty-five of them, who presented with systolic HF and were not eligible for HTx due to RFPH, wereincluded in the study (31 men aged 55.1 ± 7.4 years). In all the patients sildenafil wa…
Prognostic and therapeutic implications of dipyridamole stress cardiovascular magnetic resonance on the basis of the ischaemic cascade
2008
To determine the prognostic and therapeutic implications of stress perfusion cardiovascular magnetic resonance (CMR) on the basis of the ischaemic cascade.Single centre study in a teaching hospital in Spain.Dipyridamole stress CMR was performed on 601 patients with ischaemic chest pain and known or suspected coronary artery disease. On the basis of the ischaemic cascade, patients were categorised in C1 (no evidence of ischaemia, n = 354), C2 (isolated perfusion deficit at stress first-pass perfusion imaging, n = 181) and C3 (simultaneous perfusion deficit and inducible wall motion abnormalities, n = 66). CMR-related revascularisation (n = 102, 17%) was defined as the procedure prompted by t…
Influence of experimental diabetes on regulatory mechanisms of vascular response of rabbit carotid artery to acetylcholine
2000
Summary The purpose of this study was to analyse the influence of experimental diabetes on vascular response of rabbit carotid artery to acetylcholine (Ach). We compared the Ach-induced relaxant response of isolated arterial segments obtained from both control and diabetic animals. To assess the influence of the endothelium, this cell layer was mechanically removed in some of the arterial segments (“rubbed arteries”) from each experimental group. Ach induced a concentration-related endothelium-mediated relaxation of carotid artery from control rabbits that was significantly higher with respect to that obtained in diabetic animals. Pre-treatment with NG-nitro-L-arginine (L-NA) induced a conc…
Mechanisms underlying the inhibitory effects induced by pituitary adenylate cyclase-activating peptide in mouse ileum
2005
Abstract The aim of this study was to investigate the signal transduction mechanisms underlying the inhibitory effect induced by pituitary adenylate cyclase activating peptide (PACAP-27) on the spontaneous contractile activity of longitudinal muscle of mouse ileum. Mechanical activity of ileal segments was recorded isometrically in vitro. PACAP-27 produced apamin-sensitive reduction of the amplitude of the spontaneous contractions. 9-(Tetrahydro-2-furanyl)-9H-purin-6-amine (SQ 22,536), adenylate cyclase inhibitor, or genistein and tyrphostin 25, tyrosine kinase inhibitors, had negligible effects on PACAP-27-induced inhibition. PACAP-27 effects were significantly inhibited by U-73122, phopho…
The ineffectiveness of the NO-cyclic GMP signaling pathway in the atrial myocardium
1995
1. This study was performed to determine whether nitric oxide (NO) has direct effects on force of contraction (Fc) in atrial myocardium from rats, rabbits, guinea-pigs, frogs, and man. 2. Glyceryl trinitrate, isosorbide dinitrate, 3-morpholino-sydnonimine hydrochloride (SIN-1), and S-nitroso-N-acetylpenicillamine (SNAP) did not significantly reduce Fc in the various preparations investigated, either given alone or after stimulation of alpha- or beta-adrenoceptors. 3. SNAP did not change the time course of contractions in rat, guinea-pig and human preparations. 4. 8-Bromo-guanosine-3':5'-cyclic monophosphate (8-Br-cyclic GMP) produced a negative inotropic effect in rat, guinea-pig and human …
Nitroglycerin-induced endothelial dysfunction and tolerance involve adverse phosphorylation and S-glutathionylation of endothelial nitric oxide synth…
2011
Continuous administration of nitroglycerin (GTN) causes tolerance and endothelial dysfunction by inducing reactive oxygen species (ROS) production from various enzymatic sources, such as mitochondria, NADPH oxidase, and an uncoupled endothelial nitric oxide synthase (eNOS). In the present study, we tested the effects of type 1 angiotensin (AT(1))-receptor blockade with telmisartan on GTN-induced endothelial dysfunction in particular on eNOS phosphorylation and S-glutathionylation sites and the eNOS cofactor synthesizing enzyme GTP-cyclohydrolase I.Wistar rats were treated with telmisartan (2.7 or 8 mg/kg per day PO for 10 days) and with GTN (50 mg/kg per day SC for 3 days). Aortic eNOS phos…
No improvement in perfusion and oxygenation of experimental tumors upon application of vasodilator drugs
2001
The oxygen deficiency seen in solid tumors is predominantly caused by an insufficient O2 supply as a result of inadequate tumor perfusion. The aim of this study was to analyze whether a number of vasodilator drugs might be suitable to increase tumor perfusion and consequently improve the oxygenation status of experimental tumors. Rats with s.c. DS-sarcomas were treated with either Na+-nitroprusside (7-25 microg x min(-1) x kg(-1) BW) or nifedipine (10 microg x min(-1) x kg(-1) BW). Red blood cell (RBC) flux was assessed continuously using laser-Doppler flowmetry and mean tumor pO2 was measured polarographically using O2-sensitive catheter electrodes. Systemic application of the vasodilator …
The Effects of Sodium Nitroprusside-Induced Hypotension on Splanchnic Perfusion and Hepatocellular Integrity
1999
UNLABELLED The purpose of our study was to investigate the effects of sodium nitroprusside-induced hypotension on splanchnic perfusion and hepatocellular integrity. Thirty patients undergoing radical prostatectomy were allocated randomly to a sodium nitroprusside (SNP) or control group (control). Regional pco2 was measured using gastric tonometry, and the regional to arterial difference in partial pressure of CO2 and intramucosal pH were calculated. The cytosolic liver enzyme alpha-glutathione S-transferase and standard liver enzyme markers (alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyltransferase) were also measured. Mean arterial pressure in the SNP group was 50…
Reduction of infarct size by the NO donors sodium nitroprusside and spermine/NO after transient focal cerebral ischemia in rats
2000
Nitric oxide (NO) plays a dual role (neuroprotection and neurotoxicity) in cerebral ischemia. NO promoting strategies may be beneficial shortly after ischemia. Therefore, we have studied the hemodynamic and possible neuroprotective effects of two NO donors, the classical nitrovasodilator sodium nitroprusside (SNP) and the NONOate spermine/NO, after transient focal cerebral ischemia in rats. Parietal cortical perfusion was measured by laser-Doppler flowmetry. The effects of increasing intravenous doses (10-300 microgram) of sodium nitroprusside and spermine/NO on cortical perfusion and arterial blood pressure were assessed. Transient (2 h) focal cerebral ischemia was carried out by the intra…