Cardiovascular research
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Cardiovascular research · Feb 2001
Comparative StudyGender-related differences in left ventricular chamber function.
While women have lower rates of atherosclerotic disease than men, they are more likely to suffer cardiac failure following infarction or cardiac surgery, despite typically having a greater left ventricular (LV) ejection fraction. We hypothesised that gender differences in systolic chamber function and ventriculo-vascular coupling may contribute to these clinical findings. ⋯ This study demonstrates greater systolic chamber function and lower diastolic compliance in women. Within the range of chamber dimensions seen in patients with normal LV function, a strong relationship was found between cardiac size and end-systolic elastance. While these differences were not accounted for by indexing to body size, the greater ventricular elastance in women was removed after normalising to chamber size. Despite differences in resting ventricular elastance, appropriate ventriculo-vascular coupling was maintained in both genders as the greater end-systolic elastance in women was matched by similarly elevated arterial elastance.
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Cardiovascular research · Nov 2000
Localisation and functional significance of ryanodine receptors during beta-adrenoceptor stimulation in the guinea-pig sino-atrial node.
Recent evidence shows that calcium released from the sarcoplasmic reticulum (SR) plays an important role in the regulation of heart rate. The aim of this study was to investigate the subcellular distribution of ryanodine receptors in the guinea-pig sino-atrial (SA) node and to determine their functional role in the regulation of pacemaker frequency in response to beta-adrenoceptor stimulation. ⋯ These findings are the first to show immunocytochemical evidence for the presence and organisation of ryanodine receptor calcium release channels in mammalian SA node cells. This study also provides evidence of a role for ryanodine sensitive sites in the beta-adrenergic modulation of heart rate in this species.
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Cardiovascular research · Sep 2000
ReviewEffects of statins on vascular wall: vasomotor function, inflammation, and plaque stability.
Clinical trials of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors or statin therapy demonstrate an improvement in cardiovascular end points and coronary stenosis. However, an improvement in cardiovascular end points and coronary stenosis is incompletely explained by the baseline or treated LDL cholesterol level. The beneficial effects of statins on clinical events may involve nonlipid mechanisms that modify endothelial function, smooth muscle cells, and monocyte-macrophage: vasomotor function, inflammatory responses, and plaque stability. ⋯ Statins have been shown to prevent the activation of monocytes into macrophages, inhibit the production of pro-inflammatory cytokines, C-reactive protein, and cellular adhesion molecules. Statins decrease the adhesion of monocyte to endothelial cells. Accordingly, statins exert their cardiovascular benefits through a direct antiatherogenic properties in the arterial wall, beyond their effects on plasma lipids.
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Cardiovascular research · Aug 2000
ReviewStatus of myocardial antioxidants in ischemia-reperfusion injury.
Myocardial ischemia-reperfusion represents a clinically relevant problem associated with thrombolysis, angioplasty and coronary bypass surgery. Injury of myocardium due to ischemia-reperfusion includes cardiac contractile dysfunction, arrhythmias as well as irreversible myocyte damage. These changes are considered to be the consequence of imbalance between the formation of oxidants and the availability of endogenous antioxidants in the heart. ⋯ The available evidence support the role of oxidative stress in ischemia-reperfusion injury and emphasize the importance of antioxidant mechanisms in cardioprotection.
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Cardiovascular research · Aug 2000
IRFI 042, a novel dual vitamin E-like antioxidant, inhibits activation of nuclear factor-kappaB and reduces the inflammatory response in myocardial ischemia-reperfusion injury.
Nuclear factor-kappaB (NF-kappaB) is a ubiquitous rapid response transcription factor involved in inflammatory reactions which exerts its effect by expressing cytokines, chemokines, and cell adhesion molecules. Oxidative stress causes NF-kappaB activation. IRFI 042 is a novel dual vitamin E-like antioxidant and we, therefore, investigated its ability to protect the heart from oxidative stress and to halt the inflammatory response in a model of myocardial ischaemia-reperfusion injury. ⋯ Our data suggest that IRFI 042 is cardioprotective during myocardial infarction by limiting reperfusion-induced oxidative stress and by halting the inflammatory response.