The pressor and metabolic effects of alcohol in normotensive subjects

Changes in blood pressure, pulse rate, and plasma catecholamines, renin activity, cortisol, and calcium were studied in 16 normotensive subjects (eight with a family history of hypertension) for 5 hours following ingestion of alcohol-free and alcohol-loaded beer. Both systolic and diastolic blood pressure rose after alcohol consumption; maximum responses occurred at peak blood alcohol concentrations and were significantly higher than those seen after placebo. Pulse rate was also significantly higher after alcohol ingestion and continued to rise throughout the study. There was no difference in the pressor response to alcohol between the groups with and without a family history of hypertension. No difference was found in plasma norepinephrine or epinephrine levels between alcohol and placebo phases. However, subjects with no family history of hypertension had significantly higher plasma norepinephrine levels (p less than 0.01) than did those with a family history during both the alcohol and placebo phases, although baseline blood pressures were not significantly different. Plasma epinephrine level was similar in both groups. Plasma renin activity was unchanged throughout, but plasma cortisol fell during both phases. Plasma calcium showed a small but significant fall with alcohol consumption in both groups (p less than 0.001). These results indicate that in normotensive subjects alcohol ingestion causes a rise in systolic and diastolic blood pressure that is not influenced by a family history of hypertension. This effect does not appear to be sympathetically mediated but may be due to a direct vasoconstrictor effect of alcohol, possibly with an alcohol-induced shift in intracellular calcium.     

Hemodynamic effects of isometric exercise in normotensive and hypertensive subjects

Isometric exercise increases arterial pressure and heart rate in normotensive individuals and also in patients with labile and fixed essential hypertension. The hypertensinogenic effect of isometric exercise is mediated through an increase in cardiac output because the peripheral vascular resistance is usually not affected. The cardioaccelerating effects of isometric exercise are mediated through an initial vagal withdrawal and a later stimulation of the sympathetic system. However hypertensive patients with defective sympathetic adjustments are not immune to the hypertensinogenic and cardioaccelerating effects of isometric exercise. Since isometric exercises are performed several times during daily activities, they may result in dangerous elevations in arterial pressure in patients with already increased arterial pressure, and this may eventually lead to cerebrovascular accidents and/or cardiac decompensation. It is therefore recommended that patients with elevated arterial pressure, or persons prone to hypertension, should refrain from such activities.     

The international database of self-recorded blood pressures in normotensive and untreated hypertensive subjects.

OBJECTIVES: To pool data from individual subjects in an attempt to determine an operational threshold for making clinical decisions based on the self-recorded blood pressure (SRBP) and to examine how many hypertensive subjects, diagnosed by conventional blood pressure (CBP) measurement, would have a self-recorded blood pressure within the normotensive range if the proposed thresholds were applied. DATA SOURCES: Thirteen research groups studied 4668 untreated subjects. RESULTS: In total 2401 subjects were normotensive, 494 were borderline hypertensive and 1773 were definitely hypertensive. Hypertension had been diagnosed from the mean of 1-6 (median 3) CBP measurements obtained during 1-3 (median 1) visits. The reference values for SRBP measurements determined from the 95th percentiles of the distributions for normotensive subjects were 137 mmHg systolic and 85 mmHg diastolic. Of the subjects with systolic hypertension, 16% had systolic SRBP 相似文献   

Hemodynamic effects of nicotinic acid infusion in normotensive and hypertensive subjects

Nicotonic acid (NA) infusions are associated with peripheral vasodilation from the generation of vascular prostaglandins with minimal effects on blood pressure (BP) in normotensive subjects. We studied the effects of a NA infusion in 10 hypertensive and 11 normotensive individuals to further characterize systemic hemodynamic responses to NA using pulse waveform analysis. Blood pressure, stroke volume, cardiac output, total peripheral resistance, large and small artery elasticity were determined before and after a 1-h NA infusion. In the normotensives, systolic, diastolic, mean BP, and pulse pressure were not affected by NA. In contrast, the hypertensive subjects experienced a decrease in mean BP from 105 +/- 2 mm Hg to 100 +/- 3 mm Hg (P <.01) accompanied by significant decreases in systolic, diastolic, and pulse pressures. The differential BP response occurred despite comparable increases in heart rate (11% to 13%, P 相似文献   

The haemodynamic effects of intravenous nifedipine in normotensive and hypertensive subjects

The antihypertensive effects of intravenous nifedipine, given by bolus and 2 hour infusion, were studied at two dose levels in seven hypertensive (mean BP 178/114 mmHg) and five age-matched normotensive controls (mean BP 128/81 mmHg). Nifedipine significantly reduced systolic and diastolic blood pressure in the hypertensive patients by approximately 20%, but not in the normotensive controls. Similar changes in heart rate and forearm blood flow were seen after bolus injection in both groups, but these were not sustained during infusion. Intravenous nifedipine may be a useful acute treatment for hypertensive emergencies.     

Disparate effects of mental stress on plasma noradrenaline in young normotensive and hypertensive subjects

The response of blood pressure, heart rate and plasma catecholamines to a mental arithmetic and a cold pressor test was studied in 70 patients with mild essential hypertension and in 41 age- and sex-matched normotensives. Each group consisted of three prospectively stratified age classes: 20-29, 30-39 and 40-55 years. During mental arithmetic, hypertensives showed only a higher increment of systolic blood pressure (+17-19%) than normotensives (+12-15%). Plasma noradrenaline in the youngest normotensives (20-29 years) showed a small but significant decrease (-0.20 +/- 0.07 nmol/l) whereas the youngest hypertensives showed a small but significant increase of plasma noradrenaline (+0.14 +/- 0.04 nmol/l). The difference between both groups was highly significant (P less than 0.001). In the two older age classes there was no difference in plasma noradrenaline response between normo- and hypertensives. During the cold pressor test both the cardiovascular and plasma noradrenaline response were of the same magnitude in normo- and hypertensives. These data reinforce the concept that the increased sympathetic reactivity to mental stress in hypertensives may be restricted to the younger age.     

Forearm haemodynamics in obese normotensive and hypertensive subjects

Forearm haemodynamics using pulsed Doppler flowmetry were studied in 83 men: 15 non-obese and eight obese normotensive subjects; 30 non-obese and 30 obese hypertensive patients. Mean ages were similar in the four subgroups. The blood pressure of normotensives and hypertensives was identical in obese and non-obese subjects. Blood flow, expressed in ml/min, was significantly higher in obese subjects, whether normotensive or hypertensive. However, when blood flow was expressed per unit litre of forearm volume, it was similar in the four subgroups. Forearm vascular resistance, whether expressed as absolute or normalized values, was significantly higher (P less than 0.001) in non-obese hypertensives. When obese and non-obese hypertensives were compared, the former were characterized by higher values of blood flow velocity and blood flow, and lower values of vascular resistance, whether absolute or normalized values were used. This study shows firstly that forearm vascular resistance in hypertensives is increased exclusively in non-obese subjects, and secondly that obese hypertensives, when compared with non-obese hypertensives, are characterized by a hyperkinetic forearm circulation.     

Endothelial function in normotensive and high-normal hypertensive subjects

To evaluate the impact of a mild increment in blood pressure level on endothelial function, we evaluated 61 healthy volunteers (24 women, 37 men, and aged 35-50 years). All subjects underwent a blood chemistry panel to exclude any metabolic abnormalities and were submitted to a Doppler ultrasound of the brachial artery to assess endothelial function. We assessed the endothelial response to reactive hyperaemia and exogenous nitric oxide administration considering an increase in systolic blood pressure (SBP) at each 10-mm Hg interval. Our study population was divided as follows: SBP <115 mm Hg (SG1, n=13), SBP > or =115 mm Hg and <125 mm Hg (SG2, n=20), SBP > or = 125 mm Hg and <135 mm Hg (SG3, n=13) and SBP > or = 135 mm Hg and < 140 mm Hg (SG4, n=15). We found a significant difference in flow-mediated dilation among SG2, SG3 and SG4, 16.2+/-5.6, 13.4+/-5.2 and 11.5+/-3.6%, P<0.05, respectively). After nitrate administration, we observed a nonsignificant decrease in brachial artery dilation among groups, P=0.217. Our data showed in a healthy normotensive population, without any risk factor for atherosclerotic disease that small increases in SBP but not in diastolic blood pressure may impair endothelial function even in subjects considered as high-normal, meaning that this population deserves more attention than usually ascribed to intervene and prevent complications, as endothelial dysfunction may represent an early change in those who develop hypertension later in life.     

Serum ionized calcium and pH: effects of blood storage, some physiological influences and a comparison between normotensive and hypertensive subjects

The effects on serum ionized calcium (ICa) and pH of different storage conditions of blood or serum, and of physiological influences such as over-ventilation, food intake and dietary sodium intake have been investigated. Temperature and time-related changes in ICa occurred with storage and were minimized by immediate separation of serum and storage at 4 degrees C, (6 h or less). Elevation of serum ICa and a fall in pH accompanied increased salt intake; over-ventilation induced an elevation of serum pH and a reduction in ICa. Day-to-day intra-individual variation of ICa was 0.93%. We proceeded to examine a group of age-, sex- and race-matched hypertensive and normotensive subjects under standardized conditions designed to minimize such technical and physiological artefacts. ICa was not significantly different in the two groups; however, serum pH was significantly elevated in the hypertensive group. In the combined group of normotensive and hypertensive subjects, serum pH was significantly correlated with blood pressure. Exclusion of the black subjects from the analysis did not alter the findings.     

Cognitive performance in hypertensive and normotensive older subjects

Longitudinal studies suggest that hypertension in midlife is associated with cognitive impairment in later life. Cross-sectional studies are difficult to interpret because blood pressure can change with onset of dementia and the inclusion of subjects on treatment and with hypertensive end-organ damage can make analysis difficult. We examined cognitive performance in hypertensive and normotensive subjects without dementia or stroke >/=70 years of age. Cognitive performance was determined with the use of a computerized assessment battery in 107 untreated hypertensives (55 women, age 76+/-4 years, blood pressure, 164+/-9/89+/-7; range, 138 to 179/68 to 99 mm Hg) and 116 normotensives (51 female, age 76+/-4 years, 131+/-10/74+/-7; 108 to 149/60 to 89 mm Hg). Older subjects with hypertension were significantly slower in all tests (reaction time, milliseconds; simple, 346+/-100 versus 318+/-56, P<0.05; memory scanning, 867+/-243 versus 789+/-159, P<0.01; immediate word recognition, 947+/-261 versus 886+/-192, P<0.05; and delayed word recognition, 937+/-230 versus 856+/-184, P<0.05; picture recognition, 952+/-184 versus 894+/-137, P<0.01; spatial memory, 1390+/-439 versus 1258+/-394, P<0.01; excepting choice reaction time, 510+/-75 versus 498+/-72, P=0.08). Accuracy was also impaired in tests of number vigilance, 99.2+/-2.5% versus 99.9+/-0.9, P<0.01; delayed word recognition, 83.5+/-16 versus 87.9+/-9.8, P<0.01; and spatial memory 64+/-32 versus 79+/-20, P<0.001. Hypertension in older subjects is associated with impaired cognition in a broad range of areas in the absence of clinically evident target organ damage.     

Arterial elasticity among normotensive subjects and treated and untreated hypertensive subjects

OBJECTIVE: The aim of this study was to determine arterial elasticity in normotensive and hypertensive individuals. BACKGROUND: In addition to blood pressure, other parameters serve as markers for vascular disease. Arterial elasticity is one parameter that can be determined by a modified Windkessel model of the circulation. This model estimates, from a computerized pulse contour analysis, the proximal (capacitive) elasticity of the large arteries and the distal (reflective) elasticity of the small arteries. METHODS: A prospective, multi-center, controlled clinical study evaluated large-artery and small-artery elasticity indices in four groups: (1) normotensives without a family history of hypertension; (2) normotensives with a family history of hypertension; (3) treated and controlled hypertensives; and (4) untreated and uncontrolled hypertensives. Blood pressure, using a mercury manometer, and arterial elasticity, using a CVProfilor DO-2020 CardioVascular Profiling System (Hypertension Diagnostics, Inc., Eagan, MN, USA), were measured supine in triplicate 3 min apart in a randomized sequence. RESULTS: There were 212 evaluable subjects of mean age 46 years; 57% were women, 51% Caucasian and 33% African-American. Comparing normotensives without a family history and untreated hypertensives, both large-artery and small-artery elasticity indices were significantly different (P < 0.0001). After controlling for age and body surface area, a significant linear trend (P = 0.0001) across the four groups was detected for both large- and small-artery elasticity indices. CONCLUSION: As the hypertension status worsened, large- and small-artery elasticity indices decreased, suggesting a potential for the diagnostic use of arterial elasticity determinations.     

Effect of plasma potassium on vascular response to pressor and depressor agents in dog kidney

The effect of plasma potassium concentration on the vascular response to the pressor agent angiotensin II (ANG II) and to the depressor agent prostaglandin E2 (PGE2) was investigated in dog kidney. Renal vascular reactivity to the vasoactive agents was assessed from the change in renal blood flow (RBF) after infusion of the agent into the renal artery. Plasma potassium concentration was increased by intravenous infusion of potassium L-aspartate solution. The vascular response to ANG II was attenuated when plasma potassium was increased, i.e. percent decrease in RBF produced by ANG II (26.1 +/- 8.4%) during potassium infusion (plasma K+, 5.68 +/- 0.31 mEq/L) was significantly lower than those (35.8 +/- 9.8, 30.4 +/- 7.8%) obtained in the control period (plasma K+, 3.60 +/- 0.40 mEq/L) and in the postinfusion period (plasma K+, 4.70 +/- 0.42 mEq/L). On the other hand, the vascular response to PGE2 showed a tendency to be potentiated by elevation of plasma potassium concentration, i.e. percent increases in RBF produced by PGE2 were 44.9 +/- 10.5% in the control period (plasma K+, 3.47 +/- 0.25 mEq/L), 50.5 +/- 6.8% during potassium infusion (plasma K+, 5.45 +/- 0.25 mEq/L) and 44.9 +/- 7.2% in the recovery period (plasma K+, 4.55 +/- 0.21 mEq/L). These changes in the vascular response obtained by elevation of plasma potassium appear to act towards lowering blood pressure.     

Comparison of circulating and local adipose tissue renin-angiotensin system in normotensive and hypertensive obese subjects

The renin-angiotensin-aldosterone system (RAAS) plays a well-recognized role in the regulation of BP and in salt and water balance. Since hypertension affects a considerable proportion of obese patients, circulating RAAS has been studied in obese subjects with and without hypertension, albeit with conflicting results. Furthermore, attention has recently focused on the expression of the components of the Renin-angiotensin system (RAS) in some organs, including adipose tissue where it seems to be involved in the regulation of growth and differentiation. The aim of our study was to investigate circulating RAAS and adipose tissue RAS in obese patients with and without hypertension and in matched controls. PRA, and plasma and urinary aldosterone levels were measured in 35 obese, 30 hypertensive obese patients and in 20 controls. In addition, the expression of angiotensinogen (AGT) and angiotensin II type 1 receptor (AT1) genes was studied in sc adipose tissue from 8 obese, 6 hypertensive obese and 6 healthy subjects. As previously demonstrated in other studies, there were no significant differences in the levels of circulating RAAS components in the 3 groups. As regards local RAS, interestingly, we found that AT1 gene was significantly more expressed in sc adipose tissue from obese patients with hypertension than in those without hypertension and controls. By contrast, AGT levels were similar in the 3 groups. Our data do not support the hypothesis of an involvement of circulating RAAS in the development of obesity-related hypertension. On the other hand, local RAS seems to be differently regulated in sc adipose tissue from obese patients with hypertension with respect to normotensive obese patients and controls.     

Peripheral beta-adrenoceptor responsiveness in young normotensive and hypertensive subjects

In young subjects with normal blood pressure (N = 10) or with mild (n = 6) or moderate (n = 8) hypertension we assessed the effects of increasing doses of i.v. isoproterenol (each dose for 10 min) on systolic and diastolic blood pressure, heart rate, plasma renin activity (PRA), serum potassium and free fatty acids (FFA). Except for blood pressure, basal levels did not differ significantly between the groups. Isoproterenol induced dose-related increases in systolic blood pressure, heart rate and PRA, and dose-related decreases in diastolic blood pressure. Neither the threshold dose (i.e. the lowest dose significantly affecting these parameters), nor the changes induced by the higher doses differed between the normotensive and hypertensive subjects. Levels of serum potassium and FFA, obtained at the end of the infusion, also did not differ significantly between the groups. These results indicate, that in contrast to older and/or more severely hypertensive subjects, young subjects with mild to moderate hypertension have a peripheral beta-adrenoceptor responsiveness similar to that of normotensive controls.     

Urapidil in normotensive and spontaneously hypertensive rats: the effects on systemic and regional haemodynamics and cardiac mass

The effects of treatment for three weeks with urapidil (10 mg/kg p.o. twice daily) on systemic and regional haemodynamics and cardiac mass were studied in normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Urapidil decreased mean arterial pressure and total peripheral resistance index (176 +/- 3 versus 145 +/- 5 mmHg and 0.61 +/- 0.02 versus 0.49 +/- 0.02 units, respectively; each P less than 0.01) in SHR without affecting heart rate, cardiac index or cardiac mass. No systemic haemodynamic changes were observed in WKY rats. All organ vascular resistances decreased significantly in SHR and blood flow increased to skin (P less than 0.01) and kidneys (P less than 0.05). These data indicate that urapidil is a potent antihypertensive agent in SHR which reduced mean arterial pressure through a decreased total peripheral resistance that was distributed throughout all circulations. Despite these haemodynamic changes, cardiac mass did not change.     

血压盐敏感者内皮功能损伤及补钾的保护作用研究

目的通过观察血、尿-氧化氮（NO）水平的变化,探讨盐敏感者血管内皮功能损伤及补钾的保护作用。方法选39例年龄16～60岁、血压正常或血压轻度偏高者参与为期3周的慢性盐负荷及补钾试验,包括基线3天,低盐饮食、高盐饮食和高盐加补钾饮食各7天的研究。各个阶段测量体重、血压,并收集血、尿标本。结果盐敏感者血浆NO浓度和尿中NO水平在基线、低盐和高盐阶段均低于盐不敏感者;限盐后血、尿NO浓度增加,而高盐饮食后NO浓度显著减少;盐敏感者在高盐摄入的基础上大剂量口服补钾后血浆NO浓度、尿NO水平显著升高。结论盐敏感者尽管尚处在血压正常或血压轻度偏高阶段已存在一定程度的内皮功能损伤,且这种损伤与盐负荷相关联;大剂量补钾可能通过增加NO水平而改善盐敏感者的血管内皮功能。     

Long-term renal and systemic effects of calcium entry blockers in normotensive and experimental hypertensive dogs

The effect of diltiazem administered as a sustained infusion (10 to 15 micrograms/kg/min) was studied in 3 groups of conscious instrumented dogs: 4 normotensive, 5 Goldblatt hypertensive (GH) and 4 deoxycorticosterone acetate salt treated Goldblatt hypertensive (DSGH) dogs. Mean arterial blood pressure, left renal blood flow and heart rate were monitored, and the plasma renin activity was determined in a control session and after 3 to 5 days of diltiazem infusion in the normotensive and after 5 to 8 days of infusion in the 2 hypertensive groups. Pressor and renal blood flow responses to phenylephrine, norepinephrine and angiotensin II were also determined in the control session and on the last day of the diltiazem infusion. Mean arterial blood pressure was found to be decreased at the 5 to 8-day interval in the DSGHs and in the GHs, but the change in the latter group was not statistically significant. Mean arterial blood pressure was unchanged in the normotensives. Renal vascular resistance was decreased by diltiazem in the normotensive group at 3 to 5 days and in the DSGHs at 1 to 2 days. Heart rate was not significantly affected by diltiazem in the hypertensive groups, but was increased in the normotensive group at the 1 to 2-day interval. Plasma renin activity tended to increase in the hypertensive, but not in the normotensive dogs. Pressor and renal blood flow responses to all the agonist agents tested were decreased in the presence of diltiazem.(ABSTRACT TRUNCATED AT 250 WORDS)