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HPLC with electrochemical detection is useful in the assay of catecholamines in biological samples. Two types of chromatographic column are currently employed by most investigators: reverse phase C-18 (RPC-18) or strong cation-exchange (SCX) columns. Our aim was to evaluate the specificity, sensitivity and reproducibility of plasma and urinary catecholamine assay by these two columns. Our study indicates that both columns give very good performance for clinical purposes but sensitivity, precision at low concentration and specificity seem to be better with ion-exchange columns which are therefore preferred at the present time.

Objective:The aim of the present study was to assess the prognostic value of changes in left ventricular hypertrophy in hypertensive patients with time.Design:Two hundred and fifteen uncomplicated hypertensive patients underwent a high-quality baseline echocardiogram for left ventricular anatomy eva

Abstract —We investigated the role of angiotensin II (Ang II) and endothelin-1 (ET-1) in transgenic (mREN2)27 rats, a model of the monogenic renin-dependent form of severe hypertension and cardiovascular disease. Four-week-old heterozygous male transgenic (mREN2)27 rats (n=24) were matched according to body weight (BW) and blood pressure (BP) and randomly allocated to receive a placebo (group P), the mixed endothelin type A and B receptor antagonist bosentan (100 mg/kg BW PO, group B), the Ang II type 1–specific receptor antagonist irbesartan (50 mg/kg BW PO, group I), or the endothelin type A–selective antagonist BMS-182874 (52 mg/kg BW PO, group BMS). After 4 weeks of treatment, during which BW and BP were measured weekly, animals were euthanized, and the heart, left ventricle, right ventricle, adrenal gland, brain, and kidney were weighed. The plasma levels of adrenocortical steroids were measured by high-performance liquid chromatography. The tension responses of ET-free segments of the thoracic aorta to 5×10 −6 mmol/L phenylephrine, 60 mmol/L KCl, and cumulative doses of ET-1 were assessed. The density of ET-1 receptor subtypes in the aorta and vascular structural changes in the mesenteric arterioles (100 to 200 μm ID) were also measured with autoradiography and myography, respectively. Compared with all other groups, group I rats showed significantly ( P

Objective. To introduce a new method, the smoothness index, for assessing the homogeneity of 24 h blood pressure reduction by antihypertensive treatment and to compare it with the trough:peak ratio; and to assess the ability of both indices to predict a reduction in the left ventricular mass index induced by treatment. Patients and methods. In 174 patients with essential hypertension and left ventricular hypertrophy, enrolled in the Study on Ambulatory Monitoring of Pressure and Lisinopril Evaluation (SAMPLE), aged 20-65 years, we measured clinic blood pressure, 24 h ambulatory blood pressure and the left ventricular mass index (echocardiography) before and after treatment with lisinopril at 20 mg with the addition of 12.5 or 25 mg hydrochlorothiazide as needed to reach a sufficient blood pressure reduction. The following parameters were computed for systolic and diastolic ambulatory blood pressure: (1) hourly and 24 h blood pressure averages (± SD) at baseline and after 3 and 12 months of treatment; (2) hourly blood pressure changes from baseline after 3 and 12 months of treatment, and their average (± SD) over 24 h; (3) the trough:peak ratio after 3 and 12 months of treatment; and (4) the smoothness index after 3 and 12 months of treatment. Similar calculations were also performed at the end of a final study month during which active treatment was withdrawn and placebo was substituted (n = 164). Results. The smoothness index for systolic and diastolic ambulatory blood pressure computed after 3 months of treatment was more closely related to its corresponding values after 12 months of treatment than the trough:peak ratio values computed after the same time periods were (r = 0.68 versus 0.38 for systolic and 0.68 versus 0.42 for diastolic blood pressure, respectively). The smoothness index showed an inverse correlation with the 24 h standard deviation of systolic and diastolic blood pressure (r = -0.25 and -0.16, P < 0.01 and < 0.05, respectively, for 12 months of treatment), while the trough:peak ratio did not (r = -0.01 to -0.12, NS). A treatment-induced reduction in the left ventricular mass index was related to the smoothness index for systolic and diastolic blood pressure (r = -0.35 and -0.32, P < 0.001 with 12 months of treatment), but not to the corresponding trough:peak ratios. Conclusions. The smoothness index identifies the occurrence of a balanced 24 h blood pressure reduction with treatment and correlates with the favourable effects of treatment on left ventricular hypertrophy better than the commonly used trough:peak ratio

The aim of our study was to evaluate the relationships between endothelial function, small resistance artery structure, and blood pressure in patients with primary or secondary hypertension. Sixty subjects were included in the study: 9 patients with pheochromocytoma, 10 with primary aldosteronism, 17 with renovascular hypertension, and 13 with essential hypertension with 11 normotensive subjects who served as controls. Clinic and 24-hour ambulatory blood pressure (ABPM) were evaluated. All subjects were submitted to a biopsy of subcutaneous fat. Small resistance arteries were dissected and mounted on a micromyograph and the media/lumen ratio was calculated. A dose-response curve to acetylcholine was performed at cumulative concentrations from 10 −9 to 10 −5 mol/L. The vasodilator response to acetylcholine was similarly impaired in the four groups of hypertensive patients (ANOVA P r =34, P r =0.36, P

The effect of atrial natriuretic peptide (ANP), before and after converting enzyme (CE) inhibition, was investigated in six primary hypertensive patients taking a constant diet. In this placebo-controlled, single-blind, randomized study, the patients received, on three different days, i.v. infusions of (a) placebo, or (b) alpha-human ANP, 150 micrograms over 30 min, or (c) alpha-human ANP after acute CE inhibition by enalapril (EN) 20 mg P.O., 4 h before ANP infusion. ANP infusion increased urinary sodium (p less than 0.001) and volume excretion. Blood pressure (BP), heart rate, stroke volume and shortening fraction (echocardiography), plasma renin activity (PRA), and plasma aldosterone did not change significantly. Urinary norepinephrine and dopamine were significantly increased (p less than 0.05) after ANP infusion. BP was significantly reduced after EN in every patient (p less than 0.05). ANP infusion during CE inhibition induced a more sustained increase of sodium excretion and diuresis with respect to ANP infusion alone (p less than 0.05). PRA was significantly reduced while no further reduction of BP was observed. These data suggest that CE inhibition may increase the natriuretic and diuretic effect of ANP in hypertensive patients.

Aim of the study Patients with metabolic syndrome (MetS) have an increased risk of cardiovascular disease. Data obtained from muscle biopsies have demonstrated altered insulin signaling (IS) in patients with MetS. The IS regulates critical cell functions including molecular-regulated cellular metabolite fluxes, protein and energetic metabolism, cell proliferation and apoptosis with consequent regulation of cell life including endothelial homeostasis and blood coagulation. However, little is known about blood cell IS in MetS patients. The aim of this study was to develop a method to evaluate IS in peripheral lymphocytes to identify altered intracellular molecules in patients with MetS to use as risk biomarkers of vascular thrombosis. Patients and Methods We investigated 40 patients with MetS and 20 controls. MetS was defined according to guidelines from the US National Cholesterol Education Program Adult Treatment Panel III. Blood samples were taken from all participants. Total mononuclear cells were isolated from peripheral blood using density gradient centrifugation. IS molecules were evaluated using Western blot analysis followed by computer-assisted densitometer evaluation. Results Lymphocytes of MetS patients showed a reduced mTOR expression (the mammalian target of rapamycin) which is a fundamental molecule of IS. Major impairment of IS was confirmed by reduced upstream and downstream mTOR molecules which regulate fundamental cells metabolic functions. Conclusions In patients with MetS, we found a reduction of mTOR and other mTOR-related molecules involved in insulin resistance, cell repair, coagulation and vasculogenesis. A reduced expression of mTOR may reflect an increased risk of vascular thrombosis.