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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Stroke is a leading cause of death and disability in the world, and the worldwide burden from stroke will increase further during the 21st century. Major advances in the treatment and prevention of stroke have occurred but additional measures are needed. Much of the modern care of stroke mimics the modern treatment of heart disease, in part because of the success of thrombolytic therapy in improving outcomes. Nevertheless, the impact of thrombolytic therapy is limited because of the short therapeutic window. Additional measures are needed to limit the neurological consequences of stroke. Prevention remains a critical component of the management of patients with cerebrovascular disease. Although surgical therapies and antithrombotic medications (antiplatelet agents and anticoagulants) are effective in lessening the likelihood of stroke or recurrent stroke, new strategies are needed to lower the risk further. Measures aimed at stabilizing the vascular endothelium or preventing fracture of atherosclerotic plaques show great promise. Medications including cholesterol-lowering agents and antihypertensive medications, such as the angiotensin-converting enzyme inhibitors, appear effective in stroke prevention. These agents could be combined with antithrombotic agents and surgical interventions to lessen the risk of stroke.
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PMID:Stroke: a vascular pathology with inadequate management. 1295 49

There is extensive trial-based evidence showing that antihypertensive drugs reduce the risk of vascular events (e.g. stroke and myocardial infarction) as well as target organ damage (e.g. left ventricular hypertrophy and microalbuminuria). However, some of these benefits appear to be, at least partially, independent of the extent of blood pressure (BP) lowering. It is also evident that in certain clinical situations some antihypertensive drugs are more effective than others. In this review we discuss the effects of antihypertensive drugs on the endothelium, platelets, fibrinolysis and coagulation. These properties may account for the observed BP-independent actions. Antihypertensive drugs exert multiple effects on the vascular endothelium. These include effects on nitric oxide (NO) and angiotensin II-mediated actions. Many BP lowering drugs can inhibit platelet activity, although the relevance of this property is unknown, especially if patients are also taking platelet inhibitors (e.g. aspirin). Antihypertensive drugs also influence fibrinolysis and coagulation. These effects may be mediated by a variety of mechanisms, including altering insulin sensitivity. The haemostatic actions of antihypertensive drugs deserve greater recognition and further investigation.
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PMID:The effects of antihypertensive therapy on haemostatic parameters. 1452 58

Ephedrine is a mixed adrenergic agonist, stimulating both alpha- and beta-adrenergic receptors. The effects of ephedrine use include increases in heart rate, cardiac output, peripheral resistance, and blood pressure, and its use is associated with serious cardiovascular events such as stroke, arrhythmias, and myocardial infarction. The vascular endothelium plays a fundamental role in the regulation of vascular tone by releasing vasoactive factors such as nitric oxide (NO). The loss of NO bioactivity, often referred to as endothelial dysfunction, is characterized by the loss of endothelium-dependent vasodilation and is thought to be a common pathway for cardiovascular events such as vasospasm, hypertension, and myocardial infarction. Since endothelial dysfunction is characterized by loss of NO activity, and since ephedrine and endothelial dysfunction may be associated with similar cardiovascular events, the current study was undertaken to determine the effect of inhibition of NO production on responses to ephedrine in the rat. A sodium nitroprusside (SNP) infusion procedure was used to restore baseline vascular parameters to pre-L-NAME levels, allowing for direct comparison of agonist responses before and after NOS inhibition. The results demonstrate that the vascular response to ephedrine in the rat is modulated by NO and that NO production in response to ephedrine may be secondary to beta 2-receptor stimulation.
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PMID:Effect of inhibition of nitric oxide synthase on the vasopressor response to ephedrine. 1460 14

Haemostasis is a finely balanced and complex process ideally initiated only in response to disruption of the vascular endothelium as a means of preventing loss of blood from an injured vessel. Deviations from the ideal can lead to serious disease. Firstly, thrombosis, which arises as a consequence of inappropriate platelet-platelet interactions at a region of vessel damaged by atherosclerosis, can lead to occlusion of the affected vessel as in myocardial infarction or stroke. Secondly, loss of the ability of platelets to form aggregates leads to Glanzmann's thrombasthenia (GT) with a tendency to bleed for prolonged periods following injury. Glycoprotein IIb/IIIa (GPIIb/IIIa) plays a major role in the regulation of platelet adhesion and aggregation during haemostasis. Upon platelet activation by an agonist a signalling process is initiated, termed "inside-out" signalling, which gives rise to conformational changes within GPIIb/IIIa. These conformational changes increase the affinity of the receptor for its primary ligand, fibrinogen. Bound fibrinogen then acts as a bridging molecule facilitating the interaction of adjacent platelets. Upon fibrinogen binding GPIIb/IIIa undergoes further conformational changes and through a process termed "outside-in" signalling the receptor signals in to the platelet ultimately resulting in acceleration of the aggregation process. Qualitative or quantitative abnormalities in GPIIb/IIIa give rise to GT, a recessive bleeding disorder, and analysis of affected individuals has provided invaluable insights into the structure/function relationship of this receptor. Due to its critical role in mediating platelet aggregate formation GPIIb/IIIa has become a primary target for the development of antithrombotic agents.
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PMID:The role of the platelet glycoprotein IIb/IIIa in thrombosis and haemostasis. 1513 55

Individuals who eat salty diets and who are "salt-sensitive" tend to have increased left ventricular mass, independent of blood pressure; this phenomenon awaits an explanation. It is clear that local up-regulation of angiotensin II (AngII) production and activity play a key role in the induction of left ventricular hypertrophy (LVH). Recent evidence suggests that a healthy coronary microvascular endothelium opposes this effect by serving as a paracrine source of nitric oxide (NO), a natural antagonist of AngII activity, and that up-regulation of this mechanism can account for the protective role of bradykinin with respect to LVH. The coronary microvasculature also possesses NAD(P)H oxidase activity that can generate superoxide, inimical to the bioactivity of endothelial NO. There is now good reason to believe that the triterpenoid marinobufagenin (MBG), a selective inhibitor of the alpha-1 isoform of the sodium pump, mediates the impact of salty diets on blood pressure;production of MBG by the adrenal cortex is boosted when salt-sensitive animals are fed salty diets. It is hypothesized that coronary microvascular endothelium expresses the alpha-1 isoform of the sodium pump, and that MBG thus can target this endothelium. If that is the case, MBG would be expected to decrease membrane potential in these cells;as a consequence, superoxide production would be up-regulated, NO synthase activity would be down-regulated, and myocardial NO bioactivity would thus be suppressed. This would offer a satisfying explanation for the impact of salt and salt-sensitivity on risk for LVH. If expression of the alpha-1 isoform of the sodium pump is a more general property of vascular endothelium, MBG may suppress NO bioactivity in other regions of the vascular tree, thereby contributing to other adverse effects elicited by salty diets: reduced arterial compliance, medial hypertrophy, impaired endothelium-dependent vasodilation, hypertensive/diabetic glomerulopathy, increased risk for stroke, and hypertension.
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PMID:Marinobufagenin may mediate the impact of salty diets on left ventricular hypertrophy by disrupting the protective function of coronary microvascular endothelium. 1514 63

It was established that women in around and menopause stage have significant abnormalities in the anticoagulation system. It results in enhancing the process of thrombosis in vessels. This fact with other risk factors (high thrombin 2 concentration, high cholesterol level, high level of lower density lipoproteins, inappropriate function of vascular endothelium and others) contribute to deteriorating the vascular system with the development of ischemic heart disease, heart attack, ischemic stroke and others.
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PMID:[Effect of surgical menopause on the development of cardiovascular diseases]. 1520 65

Vascular endothelial growth factor (VEGF) is a vascular growth factor which induces angiogenesis (the development of new blood vessels), vascular permeability, and inflammation. In brain, receptors for VEGF have been localized to vascular endothelium, neurons, and glia. VEGF is upregulated after hypoxic injury to the brain, which can occur during cerebral ischemia or high-altitude edema, and has been implicated in the blood-brain barrier breakdown associated with these conditions. Given its recently-described role as an inflammatory mediator, VEGF could also contribute to the inflammatory responses observed in cerebral ischemia. After seizures, blood-brain barrier breakdown and inflammation is also observed in brain, albeit on a lower scale than that observed after stroke. Recent evidence has suggested a role for inflammation in seizure disorders. We have described striking increases in VEGF protein in both neurons and glia after pilocarpine-induced status epilepticus in the brain. Increases in VEGF could contribute to the blood-brain barrier breakdown and inflammation observed after seizures. However, VEGF has also been shown to be neuroprotective across several experimental paradigms, and hence could potentially protect vulnerable cells from damage associated with seizures. Therefore, the role of VEGF after seizures could be either protective or destructive. Although only further research will determine the exact nature of VEGF's role after seizures, preliminary data indicate that VEGF plays a protective role after seizures.
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PMID:Vascular endothelial growth factor (VEGF) in seizures: a double-edged sword. 1525 May 85

Neurological dysfunction as the first manifestation of AIDS has been found in 10 to 20% of symptomatic human immunodeficiency virus infections. However, stroke has rarely been reported in AIDS patients. The most common causes of cerebral infarction in AIDS are central nervous system infections: toxoplasmosis, cryptococcal meningitis and tuberculosis. Potential vascular mechanisms for cerebral infarction and transient neurological deficits among AIDS patients include deposition of antigen-antibody complexes with vasculitis and infarction, and a direct toxic effect of a viral antigen or infectious agent on vascular endothelium. The role of cryptococcal meningitis in vasculopathy is still not clear. We report a case of cerebral infarction in an HIV-infected patient, with cryptococcal meningitis as the first manifestation of AIDS.
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PMID:Cerebral infarction related to cryptococcal meningitis in an HIV-infected patient: case report and literature review. 1536 96

Individuals who eat salty diets and who are "salt-sensitive" tend to have increased left ventricular mass, independent of blood pressure; this phenomenon awaits an explanation. It is clear that local up-regulation of angiotensin II (AngII) production and activity play a key role in the induction of left ventricular hypertrophy (LVH). Recent evidence suggests that a healthy coronary microvascular endothelium opposes this effect by serving as a paracrine source of nitric oxide (NO), a natural antagonist of AngII activity, and that up-regulation of this mechanism can account for the protective role of bradykinin with respect to LVH. The coronary microvasculature also possesses NAD(P)H oxidase activity that can generate superoxide, inimical to the bioactivity of endothelial NO. There is now good reason to believe that the triterpenoid marinobufagenin (MBG), a selective inhibitor of the alpha-1 isoform of the sodium pump, mediates the impact of salty diets on blood pressure; production of MBG by the adrenal cortex is boosted when salt-sensitive animals are fed salty diets. It is hypothesized that coronary microvascular endothelium expresses the alpha-1 isoform of the sodium pump, and that MBG thus can target this endothelium. If that is the case, MBG would be expected to decrease membrane potential in these cells; as a consequence, superoxide production would be up-regulated, NO synthase activity would be down-regulated, and myocardial NO bioactivity would thus be suppressed. This would offer a satisfying explanation for the impact of salt and salt-sensitivity on risk for LVH. If expression of the alpha-1 isoform of the sodium pump is a more general property of vascular endothelium, MBG may suppress NO bioactivity in other regions of the vascular tree, thereby contributing to other adverse effects elicited by salty diets: reduced arterial compliance, medial hypertrophy, impaired endothelium-dependent vasodilation, hypertensive/diabetic glomerulopathy, increased risk for stroke, and hypertension.
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PMID:Marinobufagenin may mediate the impact of salty diets on left ventricular hypertrophy by disrupting the protective function of coronary microvascular endothelium. 1569 7

Macro- and microvascular disease are the most common causes of morbidity and mortality in patients with diabetes mellitus. Diabetic cardiovascular dysfunction represents a problem of great clinical importance underlying the development of various severe complications including retinopathy, nephropathy, neuropathy and increase the risk of stroke, hypertension and myocardial infarction. Hyperglycemic episodes, which complicate even well-controlled cases of diabetes, are closely associated with increased oxidative and nitrosative stress, which can trigger the development of diabetic complications. Hyperglycemia stimulates the production of advanced glycosylated end products, activates protein kinase C, and enhances the polyol pathway leading to increased superoxide anion formation. Superoxide anion interacts with nitric oxide, forming the potent cytotoxin peroxynitrite, which attacks various biomolecules in the vascular endothelium, vascular smooth muscle and myocardium, leading to cardiovascular dysfunction. The pathogenetic role of nitrosative stress and peroxynitrite, and downstream mechanisms including poly(ADP-ribose) polymerase (PARP) activation, is not limited to the diabetes-induced cardiovascular dysfunction, but also contributes to the development and progression of diabetic nephropathy, retinopathy and neuropathy. Accordingly, neutralization of peroxynitrite or pharmacological inhibition of PARP is a promising new approach in the therapy and prevention of diabetic complications. This review focuses on the role of nitrosative stress and downstream mechanisms including activation of PARP in diabetic complications and on novel emerging therapeutical strategies offered by neutralization of peroxynitrite and inhibition of PARP.
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PMID:Role of nitrosative stress and peroxynitrite in the pathogenesis of diabetic complications. Emerging new therapeutical strategies. 1572 18


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