Blunted heart rate dip during sleep and all-cause mortality.

Background: Although it has been somewhat overlooked, resting heart rate is an established predictor of cardiovascular and noncardiovascular outcome. We assessed the determinants and mortality associations of heart rate measured during ambulatory blood pressure monitoring (ABPM) to evaluate its informativeness during activity and sleep.

Methods: We studied a cohort of 3957 patients aged 55 +/- 16 (mean +/- SD) years (58% treated for hypertension) who were referred for ABPM during 1991 to 2005.

Predictors of all-cause mortality in clinical ambulatory monitoring: unique aspects of blood pressure during sleep.

The prognostic value of sleep blood pressure reported by recent studies is variable. Our aim was to examine the relationship of sleep blood pressure, measured by 24-hour ambulatory blood pressure monitoring, with all-cause mortality. We studied a cohort of 3957 patients aged 55+/-16 (58% treated) referred for ambulatory monitoring (1991-2005).

Non-dipping in diabetic patients: insights from the siesta.

Non-dipping, ie failure to lower blood pressure during sleep, has been found to be more prevalent in diabetic than in non-diabetic subjects. However, the reasons remain to be clarified. Diabetic patients may wake up more frequently during the night (for instance, due to nocturia).

The effect of the fast of Ramadan on ambulatory blood pressure in treated hypertensives.

Every year, millions of Moslems throughout the world fast from sunrise till sunset daily during the month of Ramadan, that is, experience repeated cycles of fasting-refeeding. Studies in animal models have shown that repeated cycles of fasting-refeeding may cause or exacerbate hypertension. Changes in sleeping patterns as well as changes in medication timing may also influence ambulatory blood pressure.

Effect of acute N-nitro-L-arginine methyl ester (L-NAME) hypertension on glucose tolerance, insulin levels, and [3H]-deoxyglucose muscle uptake.

This study was conducted to test the hypothesis that acute, widespread N-nitro-L-arginine methyl ester (L-NAME) induced vasoconstriction and hypertension may affect glucose tolerance and insulin sensitivity in normal rats. Comparisons were made of blood pressure, intravenous glucose tolerance, and insulin response and [3H]-deoxyglucose tissue uptake between L-NAME and control treated rats. Chronically instrumented, awake rats were administered L-NAME (30 mg/kg) (n = 8) or saline (0.

Abnormal regulation of cytosolic calcium and pH in platelets of Sabra rats in early phases of salt hypertension development.

Platelet cytosolic free calcium concentration ([Ca2+]i) and pH (pHi) have been reported to be altered in both human essential and rat spontaneous hypertension. The aim of our study was not only to search for the occurrence of such alterations in platelets of rats with salt-induced hypertension but also to investigate whether these changes might precede blood pressure rise in this form of experimental hypertension. Using fluorescent probes fura-2 and BCECF, basal values and thrombin-induced changes of [Ca2+]i and pHi were determined in platelets of young hypertension-prone (SBH) and hypertension-resistant (SBN) Sabra rats fed either low-salt (0.

Development, genotype and phenotype of a new colony of the Sabra hypertension prone (SBH/y) and resistant (SBN/y) rat model of slat sensitivity and resistance.

Objectives: Variations in the blood pressure response to salt-loading, the lack of quality control measures, and the need to prepare the strains for genetic studies led to renewed secondary inbreeding of the original colony of Sabra hypertension prone (SBH) and resistant (SBN) rats in order to regain genotypic and phenotypic homogeneity of the substrains.

Methods: Animals from the original breeding colony were selectively inbred for basal normotension and for susceptibility or resistance to the development of hypertension following salt-loading with deoxycorticosterone acetate (DOCA)-salt. Efficacy of inbreeding was tested by genome screening with 416 microsatellite primer sets.

Disparate expression of the AVP gene in Sabra hypertension-prone and hypertension-resistant rats.

We recently re-inbred the original colony of SBH-SBN rats, a model of salt-induced hypertension. In the course of phenotyping the new colony, SBH/y were found to excrete a lower urine flow with a higher urine osmolality than SBN/y. Thus disparate water handling between the substrains, a phenotype characteristic of the original colony, was retained throughout the selection procedure and transmitted down the generations to the new colony.

Nitric oxide and the regulation of blood pressure in the hypertension-prone and hypertension-resistant Sabra rat.

We examined the role of nitric oxide (NO) in the inherited resistance or susceptibility to hypertension in the Sabra hypertension-prone (SBH) and hypertension-resistant (SBN) rat. Basal mean arterial blood pressure was significantly greater in SBH than in SBN rats. Phenylephrine elevated blood pressure to a similar extent in both substrains, whereas the NO synthase inhibitor NG-monomethyl-L-arginine (L-NMMA) had a greater pressor effect in SBN rats.

The siesta and ambulatory blood pressure: is waking up the same in the morning and afternoon?

We have shown previously that blood pressure (BP) reduction after the siesta is similar to that after night sleep. As cardiovascular events cluster around morning waking hours, when there is a sharp rise of BP and heart rate (HR), the double-product of which is a major determinant of cardiac oxygen consumption, we also investigated changes after the siesta. Twenty-four-hour ambulatory BP monitorings of 156 consecutive patients referred for evaluation of hypertension who reported the siesta (afternoon nap) were analysed.

Insulin-induced renal dysfunction in regular Sabra rats.

1. We tested the effects of chronic hyperinsulinaemia on renal function. Hyperinsulinaemia, in the range of 1.

Chronic exogenous hyperinsulinaemia accelerates the development of hypertension in spontaneously hypertensive rats.

1. An association between hyperinsulinaemia, insulin resistance and hypertension was previously described in spontaneously hypertensive rats (SHR). We therefore tested whether chronic exogenous hyperinsulinaemia, which did not affect blood pressure of normotensive rats, may aggravate hypertension in young SHR.

Nitrendipine improves glucose tolerance and deoxyglucose uptake in hypertensive rats.

We assessed the effect of the vasodilating calcium channel blocker nitrendipine on glucose tolerance in young spontaneously hypertensive rats (SHR) (n = 15). The nitrendipine group received 1 g/kg chow for 3 weeks. Untreated SHR (n = 14) served as controls.

Platelet membrane microviscosity in Sabra rats with early salt hypertension.

1. To investigate the possibility that arterial hypertension is associated with changes in the physicochemical properties of cell membranes, we have studied the effects of dietary salt loading on platelet membrane microviscosity in hypertension-prone and -resistant Sabra rats. 2.

Siesta and ambulatory blood pressure monitoring. Comparability of the afternoon nap and night sleep.

A prospective analysis of consecutive ambulatory blood pressure monitorings over a 5 month period identified 50 subjects (35%) who took an afternoon nap during the monitoring. The average duration of daytime sleep, as reported by the patients, was 1.8 +/- 0.

Disparate effects of exercise training on glucose tolerance and insulin levels and on ambulatory blood pressure in hypertensive patients.

Objective: To assess the relationship of insulin levels and glucose tolerance to blood pressure in hypertension.

Design: An open, prospective trial of exercise training with ambulatory blood pressure monitoring and intravenous glucose tolerance testing before and after a 14-week training programme.

Patients: Twenty sedentary, untreated, non-obese, normoglycaemic individuals of both sexes with uncomplicated essential hypertension, of whom 16 completed the study.

Chronic exogenous hyperinsulinaemia without sugar supplementation: acute salt-sensitive hypertension without changes in resting blood pressure.

Objective: To study the effects of chronic insulin administration without sugar supplementation on blood pressure and response to acute saline loading in normal rats.

Design: Comparison of blood pressure, insulin and glucose levels in 24 insulin-treated and 12 control rats on regular rat chow (not supplemented with sugar).

Methods: Sustained-release insulin implants (or sham implantation for the control rats) were administered subcutaneously.

Comparison of verapamil and captopril in elderly hypertensive subjects: results of a randomized, double-blind, crossover study.

The effectiveness and tolerability of captopril and verapamil SR were compared in a double-blind, crossover study in 23 elderly hypertensives [15 males and 8 females, aged (mean +/- SEM) 68 +/- 1 years]. After 2 weeks of placebo run-in, patients were randomized to a starting dose of captopril, 12.5 mg b.

Insulin resistance in spontaneously hypertensive rats but not in deoxycorticosterone-salt or renal vascular hypertension.

Objective: To investigate whether the reported association between insulin resistance and hypertension in spontaneously hypertensive rats (SHR) is a primary defect or a secondary phenomenon in hypertension.

Design: Comparisons of glucose metabolism between three groups of hypertensive rats: deoxycorticosterone (DOCA)-salt hypertensive rats; two-kidney, one clip renovascular hypertensive (RVH) rats; SHR; and their respective control groups. There was also an additional group of weight-matched SHR and respective Wistar-Kyoto (WKY) controls.

Improved kidney function with cilazapril in hypertensive type II diabetics with chronic renal failure.

The purpose of this study was to determine efficacy and safety of the angiotensin converting enzyme inhibitor, cilazapril, in the treatment of hypertensive diabetics with renal insufficiency. Fifteen type II diabetics with hypertension and chronic renal insufficiency aged (mean +/- SD) 64 +/- 7 years were studied in a regional clinic and university hospital hypertension unit. The blood pressure was measured biweekly.

Sodium regulation in the affinity of renal alpha 2-adrenoceptors for epinephrine in Sabra salt-sensitive and salt-resistant rats.

Sodium ions markedly decreased in vitro renal alpha 2-adrenoceptor affinity for epinephrine in Sabra hypertensive (SBH) but not in normotensive (SBN) rats. Under these conditions, affinity of alpha 1-adrenoceptor for epinephrine was unchanged in SBH and SBN rats. If these data could be confirmed in vivo, the sodium ion, by acting as an inhibitor, could modify the effect of agonists on renal alpha 2-adrenoceptors in SBH rats.

Limitations of the captopril test in the diagnosis of renovascular hypertension.

The captopril test has been suggested as a sensitive and specific noninvasive tool for the diagnosis of renovascular hypertension. We applied the test to 72 consecutive hypertensive patients in whom renal artery stenosis was suspected. The test was positive in seven cases (9.

Acute sodium-dependent changes in membrane dynamic properties.

Na+ ions, which can play a pathogenic role in the development of high blood pressure, have been reported to regulate membrane enzymatic activities, receptor-ligand interaction and coupling of G-protein receptors to their effectors. This study was designed to investigate the in vitro effects of Na+ ions on membrane dynamic properties. The fluorescence anisotropy values of TMA-DPH (trimethylamino-diphenylhexatriene, probe selectively incorporated into the outer leaflet of the plasma membrane) was evaluated in platelets and erythrocytes of sodium-dependent hypertension-prone and -resistant rats of the Sabra Strain.