Cardiovascular research
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Cardiovascular research · Jul 1997
Angiotensin receptor type 1 mRNA in human right ventricular endomyocardial biopsies: downregulation in heart failure.
Atrial angiotensin II receptors type 1 (AT1) are downregulated in end-stage human heart failure at mRNA and protein level. The present study investigated whether AT1 ventricular mRNA content was reduced in myocardial biopsies from heart failure patients. ⋯ The quantitative RT-PCR procedure indicated a loss of ventricular AT1 mRNA in human heart failure which corresponds to the loss of AT1 protein described previously. It may underlie the decrease in AT1 protein expression in human heart failure.
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Cardiovascular research · Jun 1997
The role of cAMP- and cGMP-dependent protein kinases in the cardiac actions of the new calcium sensitizer, levosimendan.
The role of phosphodiesterase III inhibition and calcium sensitization in the cardiac actions of levosimendan, (R)-[[4-(1,4,5, 6-tetrahydro-4-methyl-6-oxo-3-pyridazinyl)phenyl]hydrazono]propane dinitrile, was studied. ⋯ Our results indicate that the cardiac effects of levosimendan at its therapeutically relevant concentrations were not mediated through PKA or PKG and its positive inotropy is therefore most probably due to the previously reported troponin-C-mediated calcium sensitization of contractile proteins.
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Cardiovascular research · May 1997
Right ventricular dysfunction persists following brief right ventricular pressure overload.
Acute pulmonary hypertension may cause right ventricular (RV) contractile failure. While it has been assumed that restoration of normal loading conditions after acute pulmonary hypertension is sufficient for complete recovery of RV function, this has not been rigorously examined. The purpose of this study was to test the hypothesis that acute RV pressure overload produces RV contractile dysfunction that persists following restoration of control loading conditions. ⋯ Acute pulmonary hypertension causes RV contractile dysfunction that persists at least 2 h after restoration of control loading conditions. Contractile dysfunction is not attributable to RV ischemia during pressure overload.
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Cardiovascular research · May 1997
Acute and persistent effects of a 46-kilometer wilderness trail run at altitude: cardiovascular autonomic modulation and baroreflexes.
To test the hypothesis that prolonged physical exercise induces long-lasting effects on blood pressure and heart rate we studied 17 endurance runners before and after the 1995 Sandia Wilderness Crossing Research Run (46 km of rocky trails, average altitude 2500 m). ⋯ The acute effects of prolonged exertion are associated with a relative increase in sympathetic activity. Twenty-four hours after this race an increased sensitivity to vagal and reduced sensitivity to sympathetic baroreflex stimulation was found. In this field study at altitude we found long-lasting effects on cardiovascular autonomic modulation after physical exertion.
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Cardiovascular research · Jan 1997
Randomized Controlled Trial Clinical TrialHaemodynamic and endocrine effects of type 1 angiotensin II receptor blockade in patients with hypoxaemic cor pulmonale.
Angiotensin II (ANG II) is known to be a potent vasoconstrictor agent in the pulmonary circulation. Furthermore, type 1 ANG II receptor blockade with losartan attenuates acute hypoxic pulmonary vasoconstriction in normal subjects. The aim of this study was therefore to evaluate the haemodynamic and endocrine sequelae of type 1 ANG II receptor blockade in patients with hypoxaemic cor pulmonale. ⋯ Thus, selective type 1 ANG II receptor blockade appears to have beneficial pulmonary and endocrine effects, suggesting a possible therapeutic role in the management of hypoxaemic cor pulmonale.