ISSN:0194-911X    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:0194-911X    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:0194-911X    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:0194-911X    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Abstract—Endothelial dysfunction is a crucial feature in the evolution of atherosclerosis. Adiponectin is an adipocyte-specific plasma protein with antiatherogenic and antidiabetic properties. In the present study, we investigated the relation between adiponectin and endothelium-dependent vasodilation. We analyzed endothelial function in 202 hypertensive patients, including those who were not taking any medication. Forearm blood flow was measured by strain-gauge plethysmography. Plasma adiponectin level was highly correlated with the vasodilator response to reactive hyperemia in the total (r=0.257,P<0.001) and no-medication (r=0.296,P=0.026) groups but not with nitroglycerin-induced hyperemia, indicating that adiponectin affected endothelium-dependent vasodilation. Multiple regression analysis of data from all hypertensive patients revealed that plasma adiponectin level was independently correlated with the vasodilator response to reactive hyperemia. Vascular reactivity was also analyzed in aortic rings from adiponectin-knockout (KO) and wild-type (WT) mice. Adiponectin-KO mice showed obesity, hyperglycemia, and hypertension compared with WT mice after 4 weeks on an atherogenic diet. Endothelium-dependent vasodilation in response to acetylcholine was significantly reduced in adiponectin-KO mice compared with WT mice, although no significant difference was observed in endothelium-independent vasodilation in response to sodium nitroprusside. Our observations suggest that hypoadiponectinemia is associated with impaired endothelium-dependent vasorelaxation and that the measurement of plasma adiponectin level might be helpful as a marker of endothelial dysfunction.

ISSN:0194-911X    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Abstract—Although heat shock proteins (Hsp’s) are present in the sera of healthy individuals and at elevated levels in subjects with early cardiovascular disease, their physiologic role in and value for predicting the development and/or progression of atherosclerosis have not been evaluated. Serum was obtained from 218 subjects with established hypertension (diastolic pressure >95 mm Hg) before their enrollment in the European Lacidipine Study on Atherosclerosis. Hsp60 and Hsp70, and anti-human Hsp60, anti-human Hsp70, and anti-mycobacterial Hsp65 antibody levels were measured by enzyme immunoassay. As an indicator of the presence/progression of atherosclerosis, the means of the maximum intima-media (I-M) thicknesses in the far walls of common carotid arteries and bifurcations (CBMmax) were determined by ultrasonography at the time of enrollment and 4 years afterward. Increases in I-M thicknesses at follow-up were less prevalent in subjects having high serum Hsp70 levels (75th percentile) at the time of enrollment (odds ratio, 0.42; 95% confidence interval [CI], 0.22 to 0.8,P=0.008). Although a similar trend was observed for serum Hsp60 levels, this was not statistically significant (odds ratio, 0.6; 95% CI, 0.32 to 1.11,P=0.10). There was no relation between anti-Hsp antibody levels and changes in I-M thicknesses. The relation between Hsp70 levels and changes in I-M thickness was independent of age, atenolol or lacidipine treatment, smoking habits, and blood lipid levels. These findings indicate that circulating Hsp70 levels predict the development of atherosclerosis in subjects with established hypertension, and an intriguing possibility is that Hsp70 protects against or modifies the progression of atherosclerosis in this subject group.

ISSN:0194-911X    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Abstract—The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) was a randomized, double-blind, active, controlled clinical trial conducted to determine whether newer antihypertensive agents, including doxazosin, an &agr;-blocker, differ from chlorthalidone, a diuretic, with respect to coronary heart disease (CHD) and other cardiovascular disease (CVD) events in hypertensive patients at high risk of CHD. In February 2000, the doxazosin treatment arm was discontinued, and findings through December 1999 were reported. This report includes an additional 9232 participant-years and 939 CVD events. At 623 clinical centers, patients (aged ≥55 years) with hypertension and at least 1 other CHD risk factor were randomly assigned to either chlorthalidone or doxazosin. The primary outcome measure was the combined occurrence of fatal CHD or nonfatal myocardial infarction (MI), analyzed by intent to treat; prespecified secondary outcome measures included all-cause mortality, stroke, combined CHD (fatal CHD, nonfatal MI, hospitalized angina, and coronary revascularization), and combined CVD (combined CHD, stroke, angina treated outside the hospital, heart failure, and peripheral arterial disease). Mean follow-up was 3.2 years. There was no difference in primary outcome between the arms (relative risk [RR], 1.02; 95% confidence interval [CI], 0.92 to 1.15). All-cause mortality also did not differ (RR, 1.03; 95% CI, 0.94 to 1.13). However, the doxazosin arm compared with the chlorthalidone arm had a higher risk of stroke (RR, 1.26; 95% CI, 1.10 to 1.46) and combined CVD (RR 1.20; 95% CI, 1.13 to 1.27). These findings confirm the superiority of diuretic-based over &agr;-blocker–based antihypertensive treatment for the prevention of CVD.

ISSN:0194-911X    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Abstract—Experimental animal models suggest that uric acid might have a pathogenic role in the early development of primary hypertension. We hypothesized that serum uric acid is correlated with blood pressure in children with new-onset, untreated, primary hypertension. We evaluated 125 consecutive children referred to the Baylor Pediatric Renal Program for evaluation of hypertension. None of the subjects had previously been evaluated or treated for hypertension. The children ranged in age from 6 to 18 years (mean, 13.4±3.3) and had normal renal function (creatinine clearance >80 mL · min−1· 1.73 m−2). Sixty-three children had primary hypertension, 40 had secondary hypertension, and 22 had white-coat hypertension. Forty controls with normal blood pressure were recruited from the renal clinic. Uric acid levels were directly correlated with systolic (r=0.80,P=0.0002) and diastolic (r=0.66,P=0.0006) blood pressure in controls and in subjects with primary hypertension and were independent of renal function. Serum uric acid concentrations >5.5 mg/dL were found in 89% of subjects with primary hypertension, in 30% with secondary hypertension, in 0% with white-coat hypertension, and in 0% of controls. We conclude that serum uric acid is directly correlated with blood pressure in untreated children and that a serum uric acid value >5.5 mg/dL in an adolescent being evaluated for hypertension strongly suggests primary hypertension as opposed to white-coat or secondary hypertension. These results are consistent with the hypothesis that uric acid might have a role in the early pathogenesis of primary hypertension.

ISSN:0194-911X    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Abstract—In rats, an increase in heart rate by pacing is accompanied by progressive large-artery stiffening. Whether this is also the case in humans is unknown. We enrolled 20 patients who were chronically implanted with a pacemaker because of atrioventricular block or sick sinus syndrome. Arterial distensibility was measured by an echo-tracking device. In 10 patients, the evaluation was performed on the radial artery by using continuous finger blood pressure measurements, whereas in the remaining 10 patients, the common carotid artery was studied with a semiautomatic measure of brachial artery blood pressure. Diastolic diameter, systodiastolic diameter change, and distensibility were obtained at baseline (heart rate 63±2 beats/min) and after atrial and ventricular sequential pacing at a heart rate of 90 and 110 beats/min. At baseline, the diameter was 7.8±0.3 mm in the carotid artery and 2.4±0.1 mm in the radial artery; the respective systodiastolic diameter change values were 375.4±31.0 and 55.9±9.0 (&mgr;m) and the distensibility values were 1.4±0.1 and 0.7±0.1 (1/mm Hg 10−3). Blood pressure and diameter were not significantly modified by increasing heart rate, which markedly modified systodiastolic diameter change and distensibility. In the radial artery, distensibility was reduced by 47% (P<0.05) at a heart rate of 90 beats/min with no further reduction at 110 beats/min. In the carotid artery, distensibility was reduced by 20% at a heart rate of 90 beats/min (P<0.05) with a further reduction at 110 beats/min (45%,P<0.05). These data provide the first evidence in humans that acute increases in heart rate markedly affect arterial distensibility and that this occurs in both large- and middle-size muscle arteries within the range of “normal” heart rate values.

ISSN:0194-911X    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Abstract—The importance of volume status on blood pressure in hemodialysis patients has long been recognized. We hypothesized that the enhanced volume dependency of blood pressure is partly determined by ventricular stiffness at end systole. A total of 115 long-term hemodialysis patients were invited to receive a comprehensive, noninvasive cardiovascular examination. End-systolic elastance was determined by using a novel, noninvasive echo-Doppler technique. The positive ratios of the interdialytic systolic blood pressure change vs weight gain during the subsequent 25 hemodialysis sessions were averaged to obtain the volume sensitivity index (mm Hg/kg). The averaged interdialytic weight gain per fat-free mass was correlated significantly with averaged percent change in systolic blood pressure (r=0.45,P<0.001). The estimated end-systolic elastance at baseline was significantly correlated with subsequently observed volume sensitivity index (volume sensitivity index=[1.17×end-systolic elastance]+6.4;r=0.34,P=0.001). End-systolic elastance was also significantly correlated with various vascular function parameters, including effective arterial elastance (r=0.48,P<0.001), pulse wave velocity (r=0.30,P=0.001), carotid augmentation index (r=0.31,P<0.001), and aortic compliance (r=−0.49,P<0.001). The results suggest that end-systolic elastance, a direct measure of left ventricular mechanical properties at end systole, is coupled to arterial mechanical properties and predicts the extent of subsequent interdialytic systolic blood pressure rise relative to weight gain. Therefore, ventricular stiffness at end systole is a determinant of the enhanced volume sensitivity of blood pressure in hemodialysis patients.

ISSN:0194-911X    

出版商:OVID    

年代:2003

数据来源: OVID