968 resultados para retinal endothelial function


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Background: The Borg Scale may be a useful tool for heart failure patients to self-monitor and self-regulate exercise on land or in water (hydrotherapy) by maintaining the heart rate (HR) between the anaerobic threshold and respiratory compensation point. Methods and Results: Patients performed a cardiopulmonary exercise test to determine their anaerobic threshold/respiratory compensation points. The percentage of the mean HR during the exercise session in relation to the anaerobic threshold HR (%EHR-AT), in relation to the respiratory compensation point (%EHR-RCP), in relation to the peak HR by the exercise test (%EHR-Peak) and in relation to the maximum predicted HR (%EHR-Predicted) was calculated. Next, patients were randomized into the land or water exercise group. One blinded investigator instructed the patients in each group to exercise at a level between ""relatively easy and slightly tiring"". The mean HR throughout the 30-min exercise session was recorded. The %EHR-AT and %EHR-Predicted did not differ between the land and water exercisegroups, but they differed in the %EHR-RCP (95 +/- 7 to 86 +/- 7. P<0.001) and in the %EHR-Peak (85 +/- 8 to 78 +/- 9, P=0.007). Conclusions: Exercise guided by the Borg scale maintains the patient's HR between the anaerobic threshold and respiratory compensation point (ie, in the exercise training zone). (Circ J 2009; 73: 1871-1876)

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Background: The MASS IV-DM Trial is a large project from a single institution, the Heart Institute (InCor), University of Sao Paulo Medical School, Brazil to study ventricular function and coronary arteries in patients with type 2 diabetes mellitus. Methods/Design: The study will enroll 600 patients with type 2 diabetes who have angiographically normal ventricular function and coronary arteries. The goal of the MASS IV-DM Trial is to achieve a long-term evaluation of the development of coronary atherosclerosis by using angiograms and coronary-artery calcium scan by electron-beam computed tomography at baseline and after 5 years of follow-up. In addition, the incidence of major cardiovascular events, the dysfunction of various organs involved in this disease, particularly microalbuminuria and renal function, will be analyzed through clinical evaluation. In addition, an effort will be made to investigate in depth the presence of major cardiovascular risk factors, especially the biochemical profile, metabolic syndrome inflammatory activity, oxidative stress, endothelial function, prothrombotic factors, and profibrinolytic and platelet activity. An evaluation will be made of the polymorphism as a determinant of disease and its possible role in the genesis of micro- and macrovascular damage. Discussion: The MASS IV-DM trial is designed to include diabetic patients with clinically suspected myocardial ischemia in whom conventional angiography shows angiographically normal coronary arteries. The result of extensive investigation including angiographic follow-up by several methods, vascular reactivity, pro-thrombotic mechanisms, genetic and biochemical studies may facilitate the understanding of so-called micro- and macrovascular disease of DM.

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BACKGROUND: The objective of this study was to investigate the effect of chronic ingestion of free and protein-associated soy isoflavones on the antioxidant status in male Wistar rats. Free isoflavone (iso), protein-associated soy isoflavone (iso + prot) and soy protein (prot) extracts were administered for 30 days by gavage to the rats at a dosage of 1 mg aglycone isoflavones per 200 g body weight, adjusted daily, and the prot group was given the same concentration of soy protein received by the iso + prot group. Antioxidant capacity of plasma, thiobarbituric acid-reactive substance (TBARS) and glutathione (GSH) levels and catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities in plasma, erythrocytes and tissues and gene expression levels in liver and kidney were evaluated. RESULTS: Chronic ingestion of free but not of protein-associated soy isoflavones nor of solely soy protein increased plasma antioxidant capacity and GPx activity in erythrocytes. Soy protein increased CAT activity and gene expression in liver. SOD activity in erythrocytes was increased by all treatments. CONCLUSION: The overall results confirm that dietary soy isoflavones have a positive effect on antioxidant status, enhancing antioxidant capacity of plasma and antioxidant enzymes in various tissues, but the effects are dependent on the form of administration and on a complex mechanism of antioxidant status balance on the organism. (C) 2010 Society of Chemical Industry

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Background: Coadministration of any statin with ezetimibe is as effective as using high doses of the same statin in the reduction Of tow-density lipoprotein cholesterol (LDL-c). There may be other effects called pleiotropics. Objective: To compare the effectiveness of 2 different treatments that obtain equivalent LDL-c reductions (80 mg of simvastatin, once a clay and coadministration of 10 mg of simvastatin and 10 mg of ezetimibe, once a day) over endothelial function and inflammation. Methods: Twenty-three randomized patients with hypercholesterolemia in a 2 X 2 crossover protocol were Studied. Endothelial function was analyzed by ultrasound assessment of endothelial dependent flow-mediated vasodilation of the brachial artery, and inflammation was estimated by high-sensitivity C-reactive protein (hs-CRP). Results: LDL-c reduction was similar between the 2 treatments with simvastatin/ezetimibe and with simvastatin (P < 0.001); no difference between treatments was found (P = 0.968). Both treatments improved significantly the endothelial function [3.61% with simvastatin/ezetimibe (P = 0.003) and 5.08%. with simvastatin (P < 0.001)]; no difference was found between the 2 treatments (P = 0.291). hs-CRP had a 23% reduction with simvastatin/ezetimibe (P = 0.004) and a 30% reduction with simvastatin alone (P = 0.01), with no significant difference between the 2 treatments (P = 0.380). Conclusion: The 2 forms of treatment presented similar pleiotropic effects: improvement in endothelial function and decrease in hsCRP levels.

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Endothelial dysfunction is an early key event of atherogenesis. Both fitness level and exercise intervention have been shown to positively influence endothelial function. In a cross-sectional study of 47 children, the relationship between habitual physical activity and flow-mediated dilation (FMD) of the brachial artery was explored. Habitual physical activity levels (PALs) were assessed using a validated stable isotope technique, and FMD of the brachial artery was measured via high-resolution ultrasound. The results showed that habitual physical activity significantly correlated with FMD (r=0.39, P=0.007), and remained the most influential variable on dilation in multivariate analysis. Although both fitness level and exercise intervention have previously been shown to positively influence FMD, this is the first time that a relationship with normal PALs has been investigated, especially, at such a young age. These data support the concept that physical activity exerts its protective effect on cardiovascular health via the endothelium and add further emphasis to the importance of physical activity in childhood.

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Background: Epidemiological studies suggest that raised plasma concentrations of total homocysteine (tHcy) may be a common, causal and treatable risk factor for atherothromboembolic ischaemic stroke. Although tHcy can be lowered effectively with small doses of folic acid, vitamin B-12 and vitamin B-6, it is not known whether lowering tHcy, by means of multivitamin therapy, can prevent stroke and other major atherothromboembolic vascular events. Purpose: To determine whether vitamin supplements (folic acid 2 mg, B-6 25 Mg, B-12 500 mug) reduce the risk of stroke, and other serious vascular events, in patients with recent stroke or transient ischaemic attacks of the brain or eye (TIA). Methods: An international, multi-centre, randomised, double-blind, placebo-controlled clinical trial. Results: As of November 2001, more than 1,400 patients have been randomised from 10 countries in four continents. Conclusion: VITATOPS aims to recruit and follow up 8,000 patients between 2000 and 2004, and provide a reliable estimate of the safety and effectiveness of dietary supplementation with folic acid, vitamin B-12, and vitamin B-6 in reducing recurrent serious vascular events among a wide range of patients with TIA and stroke. Copyright (C) 2002 S. Karger AG, Basel.

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Background: Although inflammation has a defined role in the pathogenesis of atherosclerosis, the link between rheumatoid arthritis (RA) parameters of disease activity and atherosclerotic findings are not defined. Objective: To investigate the association between subclinical carotid atherosclerosis and clinical/laboratorial parameters of RA systemic inflammatory activity. Methods: Seventy-one RA patients were consecutively selected and compared to 53 healthy controls. Smoking, diabetes and hypertension were excluded, as well as the use of statins or fibrates. B-mode carotid ultrasound was performed in all subjects. CRP, ESR and fibrinogen were determined in both groups. Clinical assessment of RA activity included DAS 28 and SDAI. Correlation between plaques and intima-media thickness (IMT) of common carotid arteries and inflammatory parameters was evaluated. Results: Carotid plaques were more prevalent in RA patients than in controls (14.1% vs. 1.9 %, p=0.02) and marginally increased IMT was observed (0.72 +/- 0.17 vs. 0.67 +/- 0.15mm, p=0.07). RA patients with plaques had older age (p=0.001) and increased IMT (p<0.001), but low SDAI (p=0.025) compared to those without plaques. RA patients with plaques had also longer disease duration, although this difference did not reach statistical significance (p=0.06). No significant correlations were found between IMT and ESR (p=0.80), CRP (p=0.75), fibrinogen (p=0.94), HAQ (p=0.89) and DAS 28 (p=0.13). Conclusions: Carotid atherosclerosis is more frequently detected in RA but its prevalence was not correlated with isolated inflammatory markers measurement or noncumulative activity scores. These findings reinforce the need to evaluate subclinical atherosclerosis in RA patients, and to find predictors of atherosclerotic lesions.

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Exercise training has an important role in the prevention and treatment of hypertension, but its effects on the early metabolic and hemodynamic abnormalities observed in normotensive offspring of hypertensive parents (FH+) have not been studied. We compared high-intensity interval (aerobic interval training, AIT) and moderate-intensity continuous exercise training (CMT) with regard to hemodynamic, metabolic and hormonal variables in FH+ subjects. Forty-four healthy FH+ women (25.0+/-4.4 years) randomized to control (ConFH+) or to a three times per week equal-volume AIT (80-90% of VO(2MAX)) or CMT (50-60% of VO(2MAX)) regimen, and 15 healthy women with normotensive parents (ConFH-; 25.3+/-3.1 years) had their hemodynamic, metabolic and hormonal variables analyzed at baseline and after 16 weeks of follow-up. Ambulatorial blood pressure (ABP), glucose and cholesterol levels were similar among all groups, but the FH+ groups showed higher insulin, insulin sensitivity, carotid-femoral pulse wave velocity (PWV), norepinephrine and endothelin-1 (ET-1) levels and lower nitrite/ nitrate (NOx) levels than ConFH- subjects. AIT and CMT were equally effective in improving ABP (P<0.05), insulin and insulin sensitivity (P<0.001); however, AIT was superior in improving cardiorespiratory fitness (15 vs. 8%; P<0.05), PWV (P<0.01), and BP, norepinephrine, ET-1 and NOx response to exercise (P<0.05). Exercise intensity was an important factor in improving cardiorespiratory fitness and reversing hemodynamic, metabolic and hormonal alterations involved in the pathophysiology of hypertension. These findings may have important implications for the exercise training programs used for the prevention of inherited hypertensive disorder. Hypertension Research (2010) 33, 836-843; doi:10.1038/hr.2010.72; published online 7 May 2010

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(ECHOCARDIOGRAPHY, Volume 26, September 2009).

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Arterial stiffness is an independent marker of cardiovascular events. Pulse wave velocity (PWV) is a validated method to detect arterial stiffness that can be influenced by several factors including age and blood pressure. However, it is not clear whether PWV could be influenced by circadian variations. In the present study, the authors measured blood pressure and carotid-femoral PWV measurements in 15 young healthy volunteers in 4 distinct periods: 8 am, noon, 4 pm, and 8 pm. No significant variations of systolic (P=.92), mean (P=.77), and diastolic (P=.66) blood pressure among 8 am (113 +/- 15, 84 +/- 8, 69 +/- 6 mm Hg), noon (114 +/- 13, 83 +/- 8, 68 +/- 6 mm Hg), 4 pm (114 +/- 13, 85 +/- 8, 70 +/- 7 mm Hg), and 8 pm (113 +/- 7, 83 +/- 10, 68 +/- 7 mm Hg), respectively, were observed. Similarly, carotid-femoral PWV did not change among the periods (8 am: 7.6 +/- 1.4 m/s, noon: 7.4 +/- 1.1 m/s, 4 pm: 7.6 +/- 1.0 m/s, 8 pm, 7.6 +/- 1.3 m/s; P=.85). Considering all measurements, mean blood pressure significantly correlated with PWV (r=.31; P=.016). In young healthy volunteers, there is no significant circadian variation of carotid-femoral PWV. These findings support the concept that it does not appear mandatory to perform PWV measurements at exactly the same period of the day. J Clin Hypertens (Greenwich). 2011;13:19-22. (c) 2010 Wiley Periodicals, Inc.

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Hahnemann considered the secondary action of medicines to be a law of nature and reviewed the conditions under which it occurs. It is closely related to the rebound effects observed with many modern drugs. I review the evidence of the rebound effect of statins that support the similitude principle. In view of their indications in primary and secondary prevention of cardiovascular diseases, statins are widely prescribed. Besides reducing cholesterol biosynthesis, they provide vasculoprotective effects (pleiotropic effects), including improvement of endothelial function, increased nitric oxide bioavailability, antioxidant properties, inhibition of inflammatory and thrombogenic responses, stabilisation of atherosclerotic plaques, and others. Recent studies suggest that suspension of statin treatment leads to a rebound imparing of vascular function, and increasing morbidity and mortality in patients with vascular diseases. Similarly to other classes of modern palliative drugs, this rebound effect is the same as a secondary action or vital reaction described by Samuel Hahnemann, and used in homeopathy in a therapeutic sense. Homeopathy (2010) 99, 255-262.

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We focused on the effect of mild hyperhomocysteinemia (HHcy) on the development of atherosclerosis, using apolipoprotein E-deficient (apoE(-/-)) and normal mice. Mice received diets enriched in methionine with low or high levels of folate, B(12) and B(6) (diets B and C, respectively), and diet only with low levels of folate, B(12) and B(6) (diets D), to induce mild HHcy. Normal mice fed on diets B, C and D presented mild HHcy, but they did not develop atherosclerotic lesions after 24 weeks of diet. In addition, increased endoplasmic reticulum stress was present in normal mice fed on diet B, compared to others groups. ApoE(-/-) mice fed on diet B for 20 weeks presented the greatest atherosclerotic lesion area at the aortic sinus than other groups. These results suggest that the methionine may have a toxic effect on endothelium, and the B-vitamins addition on diet may have a protective effect in the long term, despite the increase on homocysteine levels. Mild HHcy accelerated the development of atherosclerosis in apoE(-/-) mice, and supplementation with B-vitamins is important for prevention of vascular disease, principally in the long term. (C) 2010 Elsevier Inc. All rights reserved.

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Background: Asymmetric dimethylarginine (ADMA), produced during protein metabolism, is an endogenous inhibitor of nitric oxide synthase, but little is known about its direct vasoactive properties in different arterial beds. Material/Methods: Segments of canine coronary, renal, and femoral arteries were pretreated with increasing concentrations of ADMA, and endothelial function was evaluated in organ chambers. Results: In precontracted canine coronary arteries, the highest concentrations of ADMA inhibited endothelium-dependent relaxation mediated by acetylcholine (n=7), but no concentration of ADMA inhibited receptor-independent relaxation mediated by calcium ionophore (n=7) (P<.001). The effect of ADMA on acetylcholine-mediated relaxation was shown to be competitive inhibition of the nitric oxide synthase pathway, because the addition of L-arginine (10(-3) M), but not D-arginine (101 M), reversed the effect produced by 10(-5) M ADMA. Further, ADMA did not alter endothelium-independent relaxation mediated by sodium nitroprusside (10(-9) to 10(-6) M; n=7). Femoral arteries (n=7) and renal arteries (n=7) were more sensitive to ADMA than were coronary arteries, and they demonstrated significant ADMA inhibition to receptor dependent relaxation induced by acetylcholine (P=.03 and P=.01, respectively) and to receptor-independent relaxation induced by calcium ionophore (P=.02 and P=.01, respectively). Conclusions: Endothelium-dependent relaxation mediated by ADMA is more marked in femoral and renal arteries than in coronary arteries. The response in coronary arteries may be overall protective. Considering these different effects in various artery types, the role of ADMA as a confiable and specific cardiovascular risk factor is questioned.

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The antihypertensive effects of angiotensin-converting enzyme inhibitors (ACEi) are explained, at least in part, by enhanced bradykinin-dependent nitric oxide (NO) formation and decreased angiotensin II-induced oxidative stress and vasoconstriction. We examined for the first time whether treatment with enalapril increases the plasma levels of markers of NO formation and decreases oxidative stress in mild to moderate hypertensive patients. Eighteen untreated hypertensive patients were treated with enalapril 10 mg/day (n = 10) or 20 mg/day (n = 8) for 60 days. Eighteen normotensive healthy controls were followed for the same period. Venous blood samples were collected at baseline and after 30/60 days of treatment with enalapril. Plasma NOx (nitrites + nitrates) concentrations were determined by using the Griess reaction. Plasma nitrite and whole blood nitrite concentrations were determined by using an ozone-based chemiluminescence assay. Plasma thiobarbituric acid-reactive species (TBARS) and 8-isoprostane concentrations were determined by a fluorimetric method and by ELISA, respectively. Treatment with enalapril decreased blood pressure in hypertensive patients. However, we found no significant changes in plasma NOx, nitrite, whole blood nitrite, and in the levels of markers of oxidative stress in both normotensive controls and hypertensive patients treated with enalapril. Our data show that enalapril 10-20 mg/day does not affect the concentrations of relevant markers of NO formation or markers of oxidative stress in mild to moderately hypertensive subjects, despite satisfactory blood pressure control. Our findings do not rule out the possibility that ACEi may produce such effects in more severely hypertensive patients treated with higher doses of ACEi.

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We aim to evaluate intra- and interobserver reproducibility of brachial artery flow-mediated dilation (FMD) and of pulsatility index change (PI-C) 1 min after a 5-min forearm compression in pregnant women. Flow-mediated dilation and PI-C were assessed in 31 healthy pregnant women in 3 consecutive days, by two observers. A broader range of response to the stimulus was observed for PI-C (-58.99%-86.71%) than FMD (2.38%-27.01%). The intraclass correlation coefficients were higher for PI-C than for FMD (intra = 0.90 vs. 0.69, p = 0.047; inter = 0.94 vs. 0.61, p = 0.007). Therefore, PI-C measurements were more reliable than FMD. However, studies comprising of subjects with cardiovascular risk factors relating FMD and PI-C become necessary to validate this method for the study of endothelial dysfunction. (E-mail: wpmartins@gmail.com) (C) 2010 World Federation for Ultrasound in Medicine & Biology.