Cardiovascular research
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Cardiovascular research · Dec 1991
Effect of acute changes in aortic pressure on the coronary reserve.
The aim was to evaluate the effect of acute changes in aortic pressure on the coronary reserve and hyperaemic response. ⋯ The results suggest that coronary reserve increases during intra-aortic balloon pumping and decreases during aortic regurgitation; these changes could be attributed to the effect of the pressure changes on the hyperaemic flow.
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Cardiovascular research · Apr 1991
Comparative StudyComparison of selective arginine vasopressin V1 and V2 receptor antagonists on burn shock in the rat.
Two selective V1 and V2 receptor antagonists of arginine vasopressin, d(CH2)5Tyr(Me)AVP and d(CH2)5[D-Ile2, Ile4, Ala9-NH2]AVP, were given intravenously in burn shocked rats to investigate the respective effects of V1 and V2 receptor blockade on the haemodynamic variables in burn shock. ⋯ The V2 like receptor may be the dominating receptor mediating vasopressin's inhibitory effect on the heart. V1 receptor mediated coronary vasoconstriction contributes to the myocardial depression possibly only at the compensatory phase of shock. In addition V1 receptor mediated vasoconstriction is important in maintaining blood pressure during burn shock.
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Cardiovascular research · Mar 1991
Randomized Controlled Trial Clinical TrialEffect of dipyridamole alone and in combination with aspirin on whole blood platelet aggregation, PGI2 generation, and red cell deformability ex vivo in man.
The aim was to investigate the effects of dipyridamole, aspirin, and a combination of dipyridamole plus aspirin on platelet aggregation in whole blood, PGI2 generation, and red cell deformability ex vivo. ⋯ The results with PAF support the view that dipyridamole inhibits platelet activation by more than one mechanism; the effect on collagen induced and spontaneous platelet aggregation suggests that the effect of the combination doses is additive and that on red cell deformability the synergy is negative.
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Cardiovascular research · Mar 1991
Single bolus administration of recombinant tissue plasminogen activator: effects on infarct related vessel patency, microvascular perfusion, and microvascular reocclusion in a canine model of thrombotic occlusion/reperfusion.
The aim was to evaluate the thrombolytic efficacy of recombinant double chain tissue plasminogen activator (Duteplase, t-PA) given as a single intravenous bolus versus an infusion in a canine model of coronary arterial occlusion/reperfusion. ⋯ Single bolus administration of t-PA showed equivalent efficacy to infusion dosing in respect of IRVP, microvascular reperfusion, and microvascular reocclusion. As a result the degree of tissue necrosis (I/R ratio) was no different when comparing the two dosing regimens. Similar degrees of systemic fibrinogenolysis were observed for both treatment groups.
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Cardiovascular research · Sep 1990
Comparative Study Clinical TrialEffects of nifedipine on systemic hydraulic vascular load in patients with hypertension.
The aim of the study was (1) to determine the difference in aortic input impedance and derived parameters between hypertensives and normotensives; and (2) to assess the acute effects of nifedipine on the aortic impedance, compliance, and resistance in patients with hypertension. ⋯ The results indicate that (1) the stiffness of proximal aorta and vascular tone of peripheral arterioles are higher in hypertensives than in normotensives; (2) in hypertensive subjects, sublingual administration of nifedipine reduces the arterial pressure and peripheral arteriolar tone, but not the stiffness of proximal aorta; (3) the decrease in total external ventricular power in hypertensives treated with nifedipine results from a reduction in the steady, but not the oscillatory, component of hydraulic external ventricular power.