摘要:

Purpose:The outcome of treatment in elderly hypertensives is examined in six major randomized controlled trials. Thiazide diuretics were first- or second-line drugs in each, and P-blockers were first- or second-line drugs in four.Data identification:All compared immediate active treatment, with drugs added stepwise until blood pressure was controlled, versus withholding antihypertensive treatment unless blood pressure exceeded predetermined safety levels.Results of data analysis:Because placebo-treated patients required active treatment and actively treated patients required more than one drug, benefits were underestimated and the comparisons were not of single drugs with each other or with placebo. The incidence of fatal stroke was reduced by 33%, of fatal coronary events by 26% and cardiovascular mortality by 22%. Because cardiovascular risk varied among the trial populations, the absolute benefit from treatment varied markedly.Conclusions:In trials representative of unselected patients, treatment of diastolic hypertension might prevent cardiovascular complications in 1.4-2.2% of patients each year and fatal cardiovascular complications in 0.5-1.3% each year. In isolated systolic hypertension, treatment might prevent cardiovascular complications in 1.1% of patients each year. Generally, diuretic treatment proved superior to treatment with P-blocker, and drugs of both types were well tolerated. There is a strong case for treating elderly hypertensives with a diuretic-based regimen.

ISSN:0263-6352    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Objective:To investigate the relationship between fasting and postprandial glucose levels and the risk of hypertension, both cross-sectionally in different age and body mass index (BMI) groups, and prospectively.Design:Long-term prospective health survey in the Reykjavik area, of a large representative population sample of males and females in various age groups, conducted since 1967.Methods:Values from 8285 males and 9183 females were included in the cross-sectional analysis. The prospective analysis included 2639 males and 2346 females, with two consecutive observations for each individual, with a 3- to 8-year interval.Results:After controlling for year of examination, age, BMI and various other risk factors, we found a strongly significant relationship between the blood glucose level, both fasting and 90min after an oral glucose load, and risk for hypertension. The strength of the correlation between postprandial glucose value and blood pressure was similar in different age and BMI groups, except for in the males, in whom there was a stronger correlation with diastolic blood pressure with higher BMI. The 90-min glucose level was also predictive for development of hypertension 3-8 years later. The predictive power was somewhat stronger for females. Fasting glucose level was predictive for hypertension only for the females. Concurrent weight gain had a very strong independent explanatory power for development of hypertension.Conclusions:This study confirms the role of metabolic factors in hypertension. The correlation between impaired glucose tolerance and hypertension was found to be remarkably consistent throughout adult life, for both sexes and all values of BMI. Fasting glucose was predictive of hypertension in the females, and blood glucose at 90min after the glucose-tolerance test was predictive of future development of hypertension in both sexes.

ISSN:0263-6352    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Objective:To clarify the relationships between blood pressure and alcohol, nutrients and electrolytes intakes in Japanese men.Design and method:A dietary survey was conducted in a rural population of Japan by the 2-day dietary record method, and blood pressure was measured with a standard sphygmomanometer. Blood pressure levels, nutrients and electrolytes intakes were compared among the non-drinkers and the tertiles of the alcohol-drinking subjects. The relationships between blood pressure and nutrients, electrolytes and alcohol intakes were also determined by multiple regression analysis.Results:Age and systolic blood pressure (SBP) were positively, and percentage of energy from fat and carbohydrates was negatively, related to the drinking categories. Univariate analysis showed that SBP was significantly related to age, body mass index (BMI) and alcohol intake, and diastolic blood pressure (DBP) was also significantly related to age, BMI and alcohol intake. Both SBP and DBP had a significant inverse relationship with the percentage of energy from fat (P<0.01). Both SBP and DBP were significantly related to drinking categories when the effects of age, BMI and percentage energy from fat intake on blood pressure were adjusted for (P<0.001). Multiple regression analysis revealed SBP to be significantly and positively associated with age, BMI and alcohol intake, and negatively associated with potassium intake, whereas DBP was significantly and positively associated with BMI and total energy intake, and was negatively associated with potassium and the percentage of energy intake from fat and carbohydrates.Conclusion:The positive association between alcohol drinking and blood pressure persisted even after consideration of the effects of age, BMI and other macronutrient and electrolytes intakes. The reduction of alcohol intake should be an important public health strategy in the primary prevention of hypertension in this population.

ISSN:0263-6352    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Objective:To examine the relationships between finger and palm print (dermatoglyphic) features and, first, the presence or absence of hypertension, and, secondly, blood pressure levels in non-hypertensive subjects.Methods:Prints were available from 841 male World War II veteran twins (393 pairs, 55 individual cotwins), who were born in the USA between 1917 and 1927 and examined three different times between 1969 and 1987. At each examination the hypertensive status was assessed by blood pressure measurement, use of antihypertensive medications and two physicians' diagnostic impressions.Results:Subjects defined as hypertensive did not differ in dermatoglyphics from non-hypertensives for any trait examined. There were 60 twin-pairs discordant for hypertension; hypertensive cotwins showed lower ridge counts on the left hand, and this relationship was the opposite of what has previously been reported. Using only normotensive subjects at all three examinations, there was little consistent relationship between blood pressures (adjusted for age, body mass and alcohol consumption) and various dermatoglyphic features, except for lower palmar a-b ridge count in those with higher systolic blood pressure.Conclusions:Unless the in utero development of dermatoglyphics in relation to blood pressure is substantially different between singleton and twin pregnancies, there are no useful relationships between dermatoglyphics and hypertension or strong relationships between the presence of certain 'dermatoglyphic markers of impaired fetal development' and blood pressure in subjects who remain normotensive until early in their seventh decade.

ISSN:0263-6352    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Objective:To assess the influence of sex, race and parental history of hypertension on blood pressure and heart rate elevations during a stressor, and on the recovery of prestress baseline levels for these parameters.Design:Five hundred and thirty-seven university undergraduates underwent cardiovascular reactivity testing. A serial-subtraction task served as the stressor. Reactivity was assessed as the difference between baseline and during-task levels, and recovery as the difference between baseline and post-stress levels.Methods:The influence of sex, race and parental history of hypertension on reactivity and recovery was assessed, using analysis of variance models.Results:No differences were found in reactivity for any of the factors. For recovery, a significant effect was found for parental history of hypertension on systolic blood pressure and a marginal effect on diastolic blood pressure. Post hoc tests revealed that values in groups with two hypertensive parents remained elevated at a significantly higher level than in offspring with either no or one hypertensive parent.Conclusion:Parental history of hypertension may affect the duration of the blood pressure response to an acute stressor more than the magnitude of the response.

ISSN:0263-6352    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Objectives:To investigate the influence of heredity on obesity-associated hypertension, we evaluated casual and 24-h blood pressure, left ventricular mass and some metabolic and hormonal measurements in normotensive obese subjects.Design:Healthy, normotensive obese subjects (n=81) with positive or negative family history of hypertension were studied. Both groups were also subdivided according to a positive or a negative family history of obesity. Accordingly, 45 obese subjects had a positive family history of hypertension, 25 of these having a positive (subgroup A) and 20 having a negative family history of obesity (subgroup B). The other 36 obese subjects had a negative family history of hypertension, 19 of these having a positive (subgroup C) and 17 having a negative family history of obesity (subgroup D).Methods:Casual and 24-h systolic (SBP), diastolic (DBP) and mean blood pressure (MBP) were evaluated. Serum fasting blood sugar, total cholesterol and triglycerides levels, urinary excretion of sodium, immunoreactive fasting insulin, plasma ANF levels, plasma renin activity (PRA), plasma aldosterone level, plasma adrenaline and noradrenaline levels and echocardiographic total left ventricular mass (LVM) and LVM: height ratio were also calculated.Results:Twenty-four-hour DBP, 24-h MBP, LVM, LVM:height ratio, total cholesterol and PRA values were significantly higher in normotensive obese offspring of hypertensive parents than in obese offspring of normotensive parents. Twenty-four-hour DBP and MBP, LVM, LVM:height ratio, insulin level, insulin:glucose ratio and PRA were significantly higher in subgroup A than in subgroup B. Fasting blood sugar level, 24-h DBP and MBP, insulin level, insulin:glucose ratio, PRA, noradrenaline, adrenaline and plasma aldosterone levels were significantly higher in subgroup C than in subgroup D. Multivariate analysis also indicated that 24-h MBP and PRA levels were significantly influenced by the association between a positive family history of hypertension and obesity.Conclusions:The present results suggest that a family history of obesity might increase the risk of developing hypertension in obese subjects. An elevated PRA may precede the development of hypertension in obese subjects who are at risk for developing hypertension.

ISSN:0263-6352    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Objective:To study whether the rate of transbilayer movement of membrane cholesterol is impaired in erythrocyte membrane of normo– and hypercholesterolaemic patients with untreated essential hypertension.Design:An observational case-control study.Methods:Erythrocytes were prepared from venous blood samples obtained from normotensive subjects and hypertensive patients. The rate of transbilayer movement of membrane cholesterol was monitored in intact erythrocytes, using a radiolabelled cholesterol tracer. Erythrocytes were treated briefly or continuously with cholesterol oxidase to convert a portion of the outer leaflet cholesterol to cholestenone, and the specific radioactivity of cholestenone was determined over the period of tracer equilibration. The decrease in specific radioactivity of cholestenone reflected the transbilayer movement of radiolabelled cholesterol.Results:There were no significant differences between the diffusion of cholesterol across the erythrocyte membrane of normo– and hypercholesterolaemic hypertensive patients, but the rates were significantly lower than that estimated in control subjects. The mean±SD half– times for the process were 55.1 ±8.8 and 11.312.1 min in controls, 63.1 ±9.2 and 15.8±2.3min in normocholesterolaemic hypertensive patients, and 66.2 ±9.4 and 16.2 ±1.7 min in hypercholesterolaemic hypertensive patients, after a brief and after a continuous cholesterol oxidase treatment, respectively.Conclusion:There is a reduction in the transbilayer movement of membrane cholesterol in erythrocytes of patients with untreated essential hypertension.

ISSN:0263-6352    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Objectives:To investigate the possible immunomodulatory and regulatory functions of atrial natriuretic factor (ANF) and the natriuretic peptide C (NPR-C) receptor in the control of cytokine-stimulated nitric oxide production in primary cultures of human proximal tubular cells.Methods:Freshly prepared human proximal tubular cells were seeded on plastic plates and allowed to reach confluence. The confluent cells were then incubated with ANF or cycliC(4_23)ANF (c(4_23)ANF) alone, or preincubated with ANF or C(4_23)ANF before incubation with the nitric oxide-stimulating combination of cytokines interleukin-1|3 (10u/ml), tumour necrosis factor-cc (10ng/ml) and interferon-y (100 u/ml).Results:In the present series of experiments we have found that incubation of primary cultures of human proximal tubular cells with ANF or C(4_23)ANF stimulates nitric oxide production dose-dependently. Paradoxically, ANF acting via the NPR-C receptor also inhibits cytokine activation of the enzyme-inducible nitric oxide synthase via a cyclic GMP-independent mechanism. Both of these effects were reproduced by the NPR-C receptor-specific ligand cIn the present series of experiments we have found that incubatio4_23)ANF.Conclusions:These findings represent novel actions of ANF mediated via the NPR-C receptor. The results also provide a simple model system in which to study the subcellular mechanisms of NPR-C receptor activation.

ISSN:0263-6352    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Design:Because of uncertainties regarding the complete antihypertensive mechanism of action of β -adrenoceptor antagonists, the present study determined whether vagal afferent neurons of humans and rats possess β -adrenoceptors. Such a location would provide an appropriate target for β -blockers to modulate neurotransmission of barosensitive neurons, thereby affecting blood preessure. Therefore, in vitro receptor autoradiography of high-affinity β-adrenoceptor binding sites was performed on slices of human and rat inferior vagal (nodose) ganglia with [125l]-pindolol.Methods:Slide-mounted sections of human and rat inferior vagal ganglia were incubated with [125l]-pindolol in the absence or presence of propranolol (10u.mol/l) to define non-specific binding, atenolol (10umol/l) to inhibit binding to pradrenoceptors, or IC1118551 (3nmol/l) to inhibit binding to β2-adrenoceptors. Unilateral vagal ligation was also performed in the rat to study whether β-adrenoceptors are subject to axonal transport along the vagus nerve.Results:[125l]-pindolol bound with >90% specific binding to sections both of human and of rat inferior vagal ganglia. Specific binding occurred over both neuronal perikarya and nerve fibres. In both species the β2-adrenoceptor subtype appeared to predominate, as defined by the differential ability of IC1118551 (β2) and atenolol (β1) to inhibit the binding of [125l]-pindolol. Furthermore, unilateral vagal ligation in the rat caused an accumulation of specific binding adjacent to the ligature sites. Conclusions: We conclude that human and rat vagal afferent (and efferent) neurons possess β-drenoceptors that potentially could explain the mechanism of action of β-adrenoceptor antagonists in the therapy of hypertension.

ISSN:0263-6352    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Introduction:The transgenic rat TGR(mREN2)27 is a monogenetic rat model in hypertension research. Integration of mouse Ren-2 gene into the rat genome led to fulminant hypertension despite suppressed plasma and kidney renin concentrations. Renin is highly expressed in extrarenal tissues, especially throughout the adrenal cortex.Aims and methods:Because plasma and urinary corticosteroid concentrations are elevated during the development of hypertension in these rats, we investigated the effect of dexamethasone on blood pressure, adrenal renin and steroid metabolism.Results:A daily injection of 100 µg/kg dexamethasone for 8 weeks was capable of suppressing the development of hypertension in the transgenic rats. The same regimen did not alter blood pressure in Sprague-Dawley control rats. Plasma concentrations of adrenocorticotrophic hormone (ACTH)-dependent steroids (corticosterone and 18-hydroxydeoxycorticosterone) decreased markedly in both strains treated with dexamethasone, but more pronouncedly in transgenic rats. Surprisingly, plasma aldosterone concentrations increased exclusively in the transgenic rats, and not in control rats, treated with dexamethasone. The decrease in corticosterone and 18-hydroxydeoxycorticosterone production was accompanied by a decrease in the abundance of the messenger RNA (mRNA) encoding the rate-limiting enzyme in steroidogenesis (P450scc cholesterol side-chain cleavage) and a decrease in the mRNA encoding P450c11β (11 β-hydroxylase). The increase in aldosterone was accompanied by a massive increase in the abundance of the mRNA encoding zona glomerulosa-specific P450c11AS (aldosterone synthase), which was not increased in control rats.Conclusion:We conclude that ACTH-dependent steroids other than the mineralocorticoid aldosterone are responsible for the development of hypertension in the transgenic rat.

ISSN:0263-6352    

出版商:OVID    

年代:1995

数据来源: OVID