UMLS:C0042373 - FACTA Search

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Query: UMLS:C0042373 (vascular disease)
17,070 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Authors deal in detail with the pathophysiology of the osmolal regulation. Besides hyperosmolality the secretion of antidiuretic hormone (ADH) in increased by hypovolemia and hypotension. Secretion of ADH is lowered in hypoosmolal states. All other mechanisms are preferebly volume regulating and they influence mainly retention and excretion of sodium. Authors discuss homeostatic effects of the renin-angiotensin-aldosteron system, effects of renal failure with prevailing glomerular or tubular function disorder, impact of diuretics, natriuretic peptides, digitalis-like hormone, urodilantin and influence of the other solutes. Disorders of the effective osmolality regulation are frequent in the cerebral affections that originate from trauma, vascular disease, inflammation or tumors. Hypoosmolality and hyponatremia are presented in two different conditions: Inappropriate Vasopressin Secretion Syndrome (IADHS) and Cerebral Salt Wasting Syndrome (CSWS). Quick differential diagnose is important because the treatment of both syndromes is essentially different. Typical cause of hypernatremia is central diabetes insipidus (DI). The group of available calculated renal function parameters is applied in the differential diagnosis of these syndromes. They are creatinin clearance, excretion fraction of water and sodium, electrolyte clearance and electrolyte free water clearance. Investigation of ADH and natriuretic peptide could be even misleading. Pathophysiologic consequence of the state given by inappropriate elevation of one hormone can be the elevation of the second one.
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PMID:[Disturbances of effective osmolality regulation in disorders of the central nervous system and possible methods of monitoring]. 974 51

An intriguing problem of diabetes mellitus is the development of generalized angiopathy and concomitant hypertension. However, there is still a controversy whether beta-adrenoceptor antagonists can be used as antihypertensive agents in diabetes. Four groups of rats were investigated: nondiabetic controls, diabetes mellitus, diabetes + celiprolol (250 mg/kg body weight/day), diabetes + metoprolol (125 mg/kg body weight/day) after 6 months. Diabetes was induced by i.v. streptozotocin injection. We examined vascular structure and function histologically and by an in vitro microvideoangiometry of isolated perfused mesenterium. Additionally, we investigated the effects of hyperglycemia and celiprolol on NO release in cultivated aortic endothelial cells and the effect of celiprolol on transendothelial paracellular permeability. Diabetes resulted in endothelial dysfunction, characterized by a reduced response to acetylcholine and L-N(G)-nitro-arginine and an unchanged response to sodium nitroprusside (SNP). These effects were significantly antagonized by celiprolol but were not influenced by metoprolol treatment. This was supported by the finding of typical vascular changes associated with diabetes like media thickening, reduced cardiac capillary/muscle fiber ratio, and glomerulosclerosis, which were significantly reduced by celiprolol but not influenced by metoprolol treatment. Ketonuria improved after celiprolol treatment, whereas blood glucose, lipids, and body weight were not different between the diabetic groups. In cultured cells, celiprolol did not induce direct NO release but reversed the impairment of stimulated NO release caused by hyperglycemia. Furthermore, celiprolol reduced endothelial paracellular permeability. We conclude that celiprolol can exert antiangiopathic effects in diabetic rats and that both beta-adrenoceptor antagonists did not aggravate diabetic angiopathy and metabolic derangement.
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PMID:Different effects of the beta-adrenoceptor antagonists celiprolol and metoprolol on vascular structure and function in long-term type I diabetic rats. 1002 26

There is substantial evidence from both observational epidemiology studies and randomized controlled trials that dietary intake of sodium and potassium is important in the etiology of hypertension. However, the direct evidence for a direct link between dietary sodium and potassium and risk of cardiovascular and renovascular events is limited. Epidemiological studies should be designed to examine the relationship between dietary intake of sodium and potassium and risk of stroke, coronary heart disease, left ventricular hypertrophy, and renal disease in a prospective manner. In these studies, dietary intake of sodium and potassium should be estimated using multiple 24-hour urine collections. These studies should be focused on African Americans because they are at a disproportionately high risk of developing hypertension and blood pressure-related vascular disease. Moreover, this group has been underrepresented in most previous epidemiological studies.
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PMID:What is the role of dietary sodium and potassium in hypertension and target organ injury? 1010 Jun 88

Vascular disease is a major component of the complications associated with diabetes. The pathology involves hypertrophy and proliferation of vascular smooth muscle cells and the production and modification of extracellular matrix. The sodium/hydrogen exchanger has been widely implicated in the growth of multiple cell types, including vascular smooth muscle. Increases in sodium/hydrogen exchange activity serve as an effector or at least as an indicator of vascular activation. This article is concerned with the role of the biochemical abnormalities of diabetes exerting their pathological effects on vascular smooth muscle cells via altering sodium/hydrogen exchange activity.
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PMID:Mechanisms regulating the vascular smooth muscle Na/H exchanger (NHE-1) in diabetes. 1035 8

Hyperglycemia is a major cause of diabetic vascular disease. High glucose can induce reactive oxygen species (ROS) and nitric oxide (NO) generation, which can subsequently induce endothelial dysfunction. High glucose is also capable of triggering endothelial cell apoptosis. Little is known about the molecular mechanisms and the role of ROS and NO in high glucose-induced endothelial cell apoptosis. This study was designed to determine the involvement of ROS and NO in high glucose-induced endothelial cell apoptosis. Expression of endothelial nitric oxide synthase (eNOS) protein and apoptosis were studied in cultured human umbilical vein endothelial cells (HUVECs) exposed to control-level (5.5 mM) and high-level (33 mM) glucose at various periods (e.g., 2, 12, 24, 48 h). We also examined the effect of high glucose on H(2)O(2) production using flow cytometry. The results showed that eNOS protein expression was up-regulated by high glucose exposure for 2-6 h and gradually reduced after longer exposure in HUVECs. H(2)O(2) production and apoptosis, which can be reversed by vitamin C and NO donor (sodium nitroprusside), but enhanced by NOS inhibitor (N(G)-nitro-L-arginine methyl ether), were collated to a different time course (24-48 h) to HUVECs. These results provide the molecular basis for understanding that NO plays a protective role from apoptosis of HUVECs during the early stage (<24 h) of high glucose exposure, but in the late stage (>24 h), high glucose exposure leads to the imbalance of NO and ROS, resulting to the observed apoptosis. This may explain, at least in part, the impaired endothelial function and vascular complication of diabetic mellitus that would occur at late stages.
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PMID:Nitric oxide prevents apoptosis of human endothelial cells from high glucose exposure during early stage. 1050 98

1. 'Chelation therapy' with EDTA is being frequently used in patients with cardiovascular disease, despite limited objective evidence of effectiveness. Depressed nitric oxide (.NO)-related endothelial function accompanies atherosclerosis, and even the vascular risk factors alone, and is improved by numerous interventions that also improve prognosis in vascular disease. 2. The aim of the present study was to determine the influence of chelation therapy with EDTA alone and EDTA in combination with B vitamins on endothelial function. 3. After a control series of saline infusions, we examined the effects of a series of EDTA infusions (1.5 g, 10 times over 6 weeks) in eight subjects with coronary artery disease. In addition, because EDTA is commonly supplemented by other components, particularly B group vitamins, we subsequently examined the effect of a similar series of vitamin-supplemented EDTA infusions. 4. Forearm blood flow (FBF) was assessed by plethysmography and graded intrabrachial infusions of the endothelium-dependent vasodilator acetylcholine (ACh) and the endothelium-independent dilator sodium nitroprusside (SNP). 5. There was no difference in vasodilation to either drug after EDTA alone compared with the control periods, but the response to ACh was augmented after combined therapy (P < 0.03, ANOVA). The latter was accompanied by a small but consistent mean (+/- SEM) fall in plasma homocysteine of 1.6 +/- 0.5 mumol/L (P < 0.05). 6. The selective increase in the vasodilator response to ACh after therapy with EDTA and several B group vitamins indicates that NO-related endothelial function was improved. The absence of response to EDTA alone suggests that the supplementary vitamins were necessary for this benefit, which may have been related to the accompanying decrease in plasma homocysteine. These results, along with the current interest in the possible cardioprotective effects of vitamins and the increasing administration of 'chelation therapy', call for more definitive studies on these aspects of 'alternative medicine'.
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PMID:Effects of chelation with EDTA and vitamin B therapy on nitric oxide-related endothelial vasodilator function. 1056 4

Elevated blood cholesterol is a major risk factor for atherosclerosis. Recent studies show that lowering cholesterol reduces the risk of vascular disease, but the precise mechanisms for vascular improvement are not fully understood. Furthermore, it is not known whether the beneficial effects of cholesterol lowering extend to the skin microvasculature. In this unrandomized, open design study, we used iontophoresis and laser Doppler flowmetry to examine forearm skin perfusion in hypercholesterolaemic patients with PAOD before and after cholesterol-lowering therapy with fluvastatin. Endothelium-dependent and -independent vasodilatation were measured following skin iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP), respectively. Before cholesterol-lowering, vascular responses to ACh and SNP were reduced significantly in patients compared with responses in control subjects (p < 0.001 and p < 0.05, ANOVA, respectively). Fluvastatin therapy (40 mg/day) for 24 weeks significantly reduced total cholesterol (7.3+/-0.3 to 6.0+/-0.2 mmol/l, p < 0.001) and LDL cholesterol (5.4+/-0.5 to 4.2+/-0.4 mmol/l, p < 0.01). Vasodilatation to SNP was significantly improved at week 24 (p < 0.05). In patients with hypercholesterolaemia and PAOD, cholesterol-lowering with statin therapy significantly improved endothelium-independent vascular responses to SNP in skin microvessels. The application of the non-invasive techniques of iontophoresis and laser Doppler flowmetry may provide useful markers for the assessment of microvascular function in this group of patients.
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PMID:Lipid-lowering and skin vascular responses in patients with hypercholesterolaemia and peripheral arterial obstructive disease. 1061 27

The renin-angiotensin system (RAS) is a widely studied hormonal system that comprises substrate-enzyme interactions, the end result of which is production of the active peptide angiotensin II (Ang II). Because Ang II affects blood pressure control, sodium and water homeostasis, and cardiovascular function and structure, a great deal of research effort has been directed toward blocking the RAS. Angiotensin II may also be involved in end-organ damage in hypertension, heart failure, and vascular disease. At least two subtypes of angiotensin II receptors have been identified: AT1 and AT2. The AT1 mediates all of the known actions of Ang II on blood pressure control. Additionally, research has indicated that the AT1 receptor modulates cardiac contractility and glomerular filtration, and increases renal tubular sodium reabsorption, and cardiac and vascular hypertrophy. Less is known regarding the function of the AT2 receptor. Evidence suggests that the AT2 receptor inhibits cell proliferation and reverses AT1-induced hypertrophy. Indeed, these receptors are thought to exert opposing effects. Angiotensin II AT1 receptor antagonists (AT1RA) inhibit the RAS at the receptor level by specifically blocking the AT1 receptor subtype. These drugs induce a dose-dependent blockade of Ang II effects, resulting in reduced blood pressure, urinary protein, and glomerular sclerosis. It is postulated that AT1RA may provide end-organ protection by blocking Ang II effects via the AT1 receptor, yet leaving the AT2 receptor unopposed. Consequently, these agents may reduce the morbidity and mortality that result from myocardial infarction (MI) and other conditions resulting from structural alterations in the heart, kidney, and vasculature.
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PMID:Angiotensin II receptor blockade and end-organ protection. 1061 95

In Caucasian hypertensives and diabetics, increased RBC sodium-lithium countertransporter activity (SLC) is a marker for end-organ complications of vascular disease. A subgroup of African Americans with high Vmax for SLC show strong correlations with dyslipidaemia, insulin resistance, microalbuminuria and higher blood pressure. The purpose of our study was to determine if Vmax in premenopausal African American women correlates with left ventricular mass (LVM) before the onset of clinically diagnosed hypertension. Non-diabetic African American women (n = 35, mean age 31 years) were evaluated for cardiovascular disease risk factors, including anthropometric and blood pressure measurements, oral glucose tolerance test (OGTT), and euglycaemic hyperinsulinaemic clamp for insulin sensitivity. Fasting blood specimens were assayed for SLC activity (Vmax) and lipids. Cardiac structure was determined by 2-D echocardiography. LVM was calculated by the cube root formula and adjusted for height (LVM index). Vmax correlated significantly with average systolic blood pressure (r = 0.45, P = 0.007), diastolic blood pressure (r = 0.48, P = 0.004), mean blood pressure (r = 0.48, P = 0.003) and LVM index (r = 0.40, P = 0.02). Vmax was also associated with fasting insulin (r = 0.39, P = 0.01), the sum of insulin (r = 0.52, P = 0.002), and insulin sensitivity adjusted for fat-free mass (r = -0.55, P = 0.001). There was no statistically significant relationship between Vmax and body mass or lipids. Vmax for SLC correlates with cardiac structure in premenopausal African American women. Vmax is also associated with insulin sensitivity and insulin resistance in this non-diabetic sample. SLC activity may be useful in identifying a subgroup of young African American women with left ventricular hypertrophy and insulin resistance before the onset of clinically diagnosed hypertension and diabetes. Journal of Human Hypertension (2000) 14, 213-219.
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PMID:The association of RBC sodium-lithium countertransport (Vmax) with left ventricular mass in African American women. 1146 63

Homocysteine found in the plasma of patients with coronary heart disease, induces vascular smooth muscle cell (VSMC) proliferation and increases deposition of extracellular matrix (ECM) components. Yet, the mechanism by which homocysteine mediates this effect and its role in vascular disease is largely unknown. We hypothesized that homocysteine induces ECM production via intracellular calcium release in VSMC. To test this hypothesis, aortic VSMC from Sprague-Dawley rats were isolated and characterized by positive labeling for vascular smooth muscle alpha-actin. Early passage cells (p2-3) were grown in monolayer on coverslips. Calcium transients were quantified with fura2/AM spectrofluorometry. Homocysteine induced intracellular calcium [Ca(2+)](i) transients with an EC(50) of 60 +/- 5 nM. The EC(50) for glutathione and cysteine were 10 and 100-fold lower, respectively. Depleting extracellular calcium did not alter the homocysteine effect on intracellular calcium; however, thapsigargin pretreatment, which depletes intracellular Ca(2+) stores, abolished the homocysteine effect, demonstrating its dependence on intracellular Ca(2+) stores. Extracellular sodium depletion significantly (P < 0.05) increased [Ca(2+)](i) also suggesting a possible role of sodium-calcium exchange in the process. To begin to elucidate the intracellular pathways by which homocysteine might act, VSMC were pretreated with specific inhibitors and stimulators prior to homocysteine stimulation. Staurosporine and phorbol myrisate acetate (PMA), potent simulators of protein kinase C, augmented the release of Ca(2+) by homocysteine. Interestingly, pretreatment with the nitric oxide synthase inhibitor N-nitro-L-arginine methyl ester (L-NAME) greatly exacerbated the sensitivity of VSMC to homocysteine. In contrast, pretreatment with either the phospholipase A(2) activator neomycin, the antioxidant and hepatic hydroxymethyl glutaryl coenzyme A (HMG CoA) reductase inhibitor, pravastatin, the tyrosine kinase inhibitor genestein, or the calcium channel blocker, felodipine completely inhibited the homocysteine-induced Ca(2+) signal in VSMC. This suggests the role of multiple signaling pathways in the homocysteine effect on VSMC Ca(2+). Effects of homocysteine on collagen production, as ascertained by immunoblot analysis, correlated with its effect in intracellular calcium. Regardless of the signaling pathways involved, homocysteine, by virtue of its role on VSMC proliferation and ECM deposition, has the potential to affect vascular reactivity. To determine the effect of homocysteine on the ability of VSMC to react to potent agonist such as angiotensin II, VSMC were pretreated with homocysteine and exposed to a range of angiotensin II concentrations which normally have no effect on intracellular Ca(2+). After homocysteine pretreatment, VSMC were extremely responsive to angiotensin II at concentrations well below the physiologic range. These data taken together suggested that an initial effect of homocysteine is to induce release of intracellular Ca(2+) in VSMC and may induce vascular reactivity. The transient in Ca(2+) correlates with the effect on ECM associated with homocysteine.
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PMID:Homocyst(e)ine induces calcium second messenger in vascular smooth muscle cells. 1069 63

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