Plasma melatonin concentrations in hypertensive patients with the dipping and non-dipping blood pressure profile

Some patients with hypertension exhibit disturbed circadian organization in the cardiovascular system. Hormone melatonin can synchronize circadian rhythms and its repeated administration can improve synchronization of rhythmicity in blood pressure (BP). In our study we measured endogenous melatonin production in patients with essential hypertension exhibiting a dipping and non-dipping BP profile. Blood pressure was monitored for at least 24-hr with an automatic ambulatory BP monitor and patients with no decline in BP were classified as non-dippers. Plasma melatonin was measured in the middle of the daytime and night-time by radioimmunoassay. As expected night-time systolic (P <0.05), diastolic (P <0.001) and mean arterial (P <0.001) BP was higher in non-dippers than in dippers. No significant difference was found between both groups in BP during the day. Mean melatonin concentrations were higher during the night than during the day in both dippers and non-dippers. When patients were divided into dippers and non-dippers on the basis of mean arterial or diastolic BP a lower ratio of night/day concentration was determined in non-dippers than in dippers. Our study showed a blunted night/day difference in plasma melatonin concentrations in hypertensive patients with the non-dipping profile in diastolic BP indicating disturbances in the circadian system of these patients.     

Relationship between clinical, 24-hour, average day-time and night-time blood pressure and measures of arterial stiffness in essential hypertension

Arterial wall stiffness is considered an independent cardiovascular risk factor. Aim of this study was to evaluate relationship between clinical, 24-hour, average day-time and night-time blood pressure (BP) and measures of arterial stiffness assessed by pulse wave velocity (PWV) (using SphygmoCor applanation tonometer) in essential hypertension (severe-resistant (RH, n=29) and moderate hypertension (EH, n=35)) and in normotensive control subjects (n-29) (NCS) matched by age. After multiple regression analysis, PWV remains significantly correlated mainly with night-time pulse pressure and to a lesser extent with age. PWV was significantly higher in RH compared to moderate EH and NCS.     

ACE2基因多态性与高血压患者血压昼夜节律变化相关性研究

目的:研究血管紧张素转换酶2(ACE2)基因多态性与高血压患者血压昼夜节律变化的关系.方法:选择符合入选标准的高血压患者336例,采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)的方法,进行ACE2基因分型.根据血压昼夜节律变化,将高血压患者分为勺型与非勺型两组.分析基因型是否为非勺型血压的危险因素.结果:男性勺型组与非勺型组ACE2基因型多态性的分布存在显著差异,勺型组以G等位基因携带者为主.结论:ACE2基因多态性与男性高血压患者血压昼夜节律相关,携带G等位基因的患者可能更易发生夜间血压升高.     

高血压患者心电图左心室高电压和左心室肥厚与血压的关系

目的:探讨原发性高血压患者常规心电图检测左心室高电压和左心室肥厚与血压的关系.方法:回顾分析我科2009年1月～2009年12月门诊及住院就医的各期原发性高血压患者92例临床资料,并与同期76例健康体检者对比.结果:高血压组心电图对左心室肥厚的检出率为15.22%,明显高于对照组,有统计学差异(x2=19.07,P<0.01);高血压组心电图对左心室高电压的检出率为20.65%,明显高于对照组,有统计学差异(x2=4.23,P<0.05).高血压组左心室肥厚率随着病情的加重逐渐加重,各级之间相比差异有统计学意义(P<0.01).左心室高电压情况各级之间相比差异亦有统计学意义(P<0.01),但与病情无明显的相关性.结论:心电图监测左心室肥厚和左心室高电压,简便易行,高血压患者应定期复查心电图,发现异常,积极降压等治疗.     

Effect of nifedipine and propranolol on blood flow,venous compliance and blood pressure in essential hypertension

To determine the efficacy of nifedipine combined with propranolol in the treatment of hypertension, 23 patients with essential hypertension uncontrolled while they were receiving propranolol, 120 mg/d, entered a dose response trial of four 8-week periods while continuing propranolol therapy. Therapy during the four periods consisted respectively of a placebo, 30 mg/d of nifedipine, 30 or 60 mg/d of nifedipine, and 30 or 60 mg/d of nifedipine along with only 60 mg/d of propranolol. Studies of forearm blood flow and venous compliance were carried out in nine of the patients. Ten patients dropped out after the first period. The mean blood pressures while the patients were recumbent after the first, second and third periods were 163 ± 17/100 ± 6, 147 ± 13/89 ± 10 and 141 ± 19/84 ± 10 mm Hg respectively. There was no evidence of tolerance in the four patients who received 30 mg/d of nifedipine during the third period. There was a significant dose-diastolic pressure response (p < 0.0006) without a change in heart rate in the eight who received 60 mg/d of nifedipine during this period. After 16 weeks of therapy with nifedipine 11 patients had a diastolic pressure less than 90 mm Hg while recumbent. While mean blood pressure and heart rate for the group were not significantly increased at the end of the fourth period, in three of the patients the diastolic pressure while recumbent increased to over 90 mm Hg. This suggests that 120 mg/d of propranolol is the minimum dose required for concomitant therapy. Adverse symptoms were mild and transient. Forearm plethysmography showed that nifedipine induced arteriolar but not venous dilation and that propranolol attenuated the vasodilator effect of nifedipine. The author concludes that nifedipine was safe and effective in combination with propranolol in this group of patients with essential hypertension.     

Relation between arterial pressure,dietary sodium intake,and renin system in essential hypertension.

Forty-one patients with mild essential hypertension, 36 patients with severe hypertension, and 28 normotensive subjects were studied on a high sodium intake of 350 mmol/day for five days and low sodium intake of 10 mmol/day for five days. The fall in mean arterial pressure on changing from the high-sodium to the low-sodium diet was 0.7 +/- 1.7 mm Hg in normotensive subjects, 8 +/- 1.4 mm Hg in patients with mild hypertension, and 14.5 +/- 1.4 mm Hg in patients with severe hypertension. The fall in blood pressure was not correlated with age. Highly significant correlations were obtained for all subjects between the ratio of the fall in mean arterial pressure to the fall in urinary sodium excretion on changing from a high- to a low-sodium diet and (a) the level of supine blood pressure on normal diet, (b) the rise in plasma renin activity, and (c) the rise in plasma aldosterone. In patients with essential hypertension the blood pressure is sensitive to alterations in sodium intake. This may be partly due to some change either produced by or associated directly with the hypertension. A decreased responsiveness of the renin-angiotensin-aldosterone system shown in the patients with essential hypertension could partly account for the results.     

Relationship between blood pressure and Alzheimer's disease in Linxian County,China

To investigate the relationship between hypertension and Alzheimer's disease(AD) and the change of Alzheimer's patients' blood pressure(BP) before and after the onset of AD, we conducted this epidemiological study. Subjects for this study were individuals who participated in a large scale, randomized controlled trial of nutritional intervention from 1984 to 1991. Participants were initially screened for dementia using Chinese Mini-Mental State Examination (CMMS) and Activities of Daily Living (ADL). Positive subjects were subsequently administered a detailed neuropsychological and neurobehavioral examination. The diagnosis of AD was made by a consensus conference of psychiatrists using Diagnostic And Statistical Manual Of Mental Disorders-Fourth Edition(DSM-IV) criteria. 16488 subjects were examined and 301 were diagnosed as AD. We compared the prevalence of AD in different populations that were stratified with 1984's systolic or diastolic blood pressure(those four stratifications being high blood pressure, borderline blood pressure, normal, low blood pressure), and compared the change of blood pressure of 301 AD patients between 1984 and 1999-2000, which is before and after the onset of AD respectively. Multiple Logistic Regression (1:1 nested case-control study) was used to assess if hypertension is an independent risk factor for AD, and Trend test was used to assess the relationship between blood pressure and AD. Here we demonstrate that there was a significant difference in AD prevalence among different populations stratified by systolic or diastolic blood pressure (P < 0.01).The prevalence is highest in hypertension group, and lowest in hypotension group. Multiple Logistic Regression identified high blood pressure as a risk factor for AD (OR = 1.97, 95%CI:1.09-3.54, P = 0.02). Trend test showed that there is a significant dose-response relationship between blood pressure and AD (P < 0.0002). For hypertensive AD patients, there was no significant difference in systolic blood pressure(SBP) before and after the onset of AD, but diastolic blood pressure(DBP) decreased dramatically after the onset of AD (P < 0.01); however, the result also showed that DBP decrease occurred in the non-demented group. Based on this, we think the DBP decrease is not related to AD. We further investigated whether BP values differed crossed-sectionally between the AD-patients and non-demented individuals. We found that regardless of SBP or DBP, the BP values of the AD group were all significantly higher than that of non-demented. In summary, these data suggest there is a strong relationship between hypertension and AD; however, the mechanism remains to be studied.     

Relationship between mercury concentration in blood, cognitive performance, and blood pressure, in an elderly urban population

Concentration of mercury (Hg) in whole blood in an elderly urban population with a mean age of 87 years was studied in relation to cognitive function, arterial blood pressure (arterial BP), age, gender, body mass index (BMI) and smoking habits. This population-based study consisted of 106 subjects both males and females. Clinical assessment of the subjects included medical and social history, physical and neurologic examination and assessment of cognitive functions with Mini-Mental State Examination (MMSE). Information on use of all potentially anti-hypertensive drugs was collected. Whole blood from 106 subjects were collected and analysed for mercury by Cold Vapour Atomic Absorption Spectrometry (Milton Ray ASS-CV) with Seronorm Trace Element as matrix matched quality control. Males and females did not differ in blood-mercury (B-Hg) concentrations or in any of the other studied variables. B-Hg concentrations did not differ between smokers and non-smokers. Females were treated more often than males with antihypertensive drugs. There was no relation found between B-Hg concentration and cognitive function, arterial BP, age, gender or BMI. In conclusion, no relations were found between B-Hg concentrations and the studied variables.     

Interrelationship between serum lipid profile,serum hormones and other components of the metabolic syndrome

The aim of the present study was to investigate the association between the serum lipid profile and components of the metabolic syndrome, such as central obesity (anthropometric, computed tomography and fat cell data), insulin, sex-hormone-binding-globulin (SHBG) and different hormones influencing this important syndrome, e.g. sex steroids, leptin and tumor necrosis factor-alpha (TNF-alpha). The sample consisted of 85 obese patients (30 men and 55 women) who had undergone abdominal surgery. Fasting serum lipids were analysed, as well as anthropometric and computed tomography data, perivisceral and subcutaneous fat cell size and serum glucose and hormones. Abdominal fat revealed itself as an important correlator of the adverse changes in plasma lipoprotein levels, the waist-to-hip-ratio and waist-to-thigh-ratio being the best morphological correlators in men and women, respectively. Intra-abdominal fat (VA) correlated significantly and positively to perivisceral fat cell size in women, while no correlation was found between subcutaneous fat accumulation (SA) and adipocyte size in both genders. Perivisceral fat cell size showed the greatest number of correlations with the adverse plasma lipid profile compared to that in the subcutaneous depot. SHBG and sex steroids showed a negative correlation with serum lipids considered a cardiovascular risk. In contrast, TNF-alpha and C-peptide were inversely correlated with potential protector lipids. In conclusion, abdominal obesity, adipocyte hypertrophy from visceral fat, serum TNF-alpha and C-peptide seem to be the best correlators of the lipoprotein disturbance characteristic of the metabolic syndrome, whereas SHBG and sex steroids could play a protective role regarding the lipid profile associated to this syndrome.     

Effect of somatostatin on plasma renin activity and blood pressure in patients with essential hypertension

The effects of somatostatin on plasma renin activity (PRA) and blood pressure were evaluated in patients with essential hypertension (EH) and in normotensive subjects. All subjects examined were hospitalized and placed on a diet containing 7-8 g/day sodium chloride and received an intravenous infusion of somatostatin (500 microgram/20 ml of saline, for 60 min) in the basal condition. During somatostatin infusion, the mean blood pressure (MBP) remained unaffected in all patients with EH and the normotensive subjects, while the PRA decreased slightly in the EH group. When the patients with EH were classified according to their renin levels (low, normal and high), parallel significant decreases in MBP and PRA were found only in the high renin group during the somatostatin infusion. No significant change in MBP and PRA was observed in the other groups including the normotensive subjects. To assess the activity of synthetic somatostatin, the plasma levels of growth hormone (GH) and cyclic AMP were measured. These levels were lowered significantly during the infusion and the GH levels showed a rebound 15 min after cessation of the infusion. The cyclic AMP returned to the basal levels, but no rebound was observed. The above data indicate that the fall in blood pressure in the high renin group in the basal condition was probably due in part to reduced renin release by somatostatin, and the maintenance of high blood pressure especially in high renin EH.     

Relationship between blood pressure,sleep K-complexes,and muscle sympathetic nerve activity in humans

Stage 2 sleep is characterized by the EEG appearance of "K-complexes" and blood pressure oscillations. K-complexes may be directly related to blood pressure changes or they may reflect central sympathetic activation. We analyzed the temporal relationship among K-complexes, heart rate (HR), blood pressure (BP), and muscle sympathetic nerve activity (MSNA) during sleep in eight healthy volunteers (3 men and 5 women, age 22-41 yr). Most K-complexes presented as single large complexes (56 +/- 20%), followed by single small complexes (15 +/- 14%) and as couplets or triplets (13 +/- 6%). Single large K-complexes were preceded by a baroreflex-mediated increase of MSNA in approximately one-half (55%) of the cases. Detailed analysis of HR, BP, and MSNA was possible in 63 (45%) large single K-complexes not disturbed by preceding baroreflex-related changes. Systolic and diastolic BP and MSNA increased significantly after single events (22.5 +/- 13, 5.2 +/- 2.1, and 6.5 +/- 3.0%). Mean sympathetic baroreflex latency was similar after the single large K-complexes compared with the mean value during stage 2 sleep (1,290 +/- 126 vs. 1,279 +/- 61 ms). The area under the burst was significantly increased after single large K-complexes (median 3.9 vs. 9.0 arbitrary units, P < 0.03). The results support the hypothesis that K-complexes express cortical activation leading to temporary facilitation of sympathetic outflow in a graded fashion. Their functional effects appear to be independent of baroreflex modulation of MSNA in approximately 50% of the cases.     

Relationship between African admixture and blood pressure variation in the Caribbean

The genetic contribution to blood pressure variance is examined by studying a selected group of genes. Of 368 individuals, 48.1% received one-half or more of their genes from an African ancestor and of this group 18.1 and 17.0% exhibit systolic and diastolic hypertension, respectively. A chi-square test was used to examine the dependence of blood pressure on percentage African ancestry. The chi-square values were not significant for systolic or diastolic pressures. It is likely that other factors are strongly related to African admixture and these factors are the true modifiers of blood pressure.     

Adiponectin gene polymorphism is selectively associated with the concomitant presence of metabolic syndrome and essential hypertension

Objective

Cardiovascular risk increases with the presence of both metabolic syndrome (MetS) and hypertension (HTN). Although the adiponectin (ADIPOQ) gene has been reported to be involved in MetS, its association with HTN remained undetermined. This study aimed to investigate the association of ADIPOQ gene with the phenotypes of HTN and MetS.

Methods

A total of 962 participants from 302 families from the Taiwan young-onset hypertension genetic study were enrolled. Plasma adiponectin were measured, and association analysis was conducted by using GEE regression-based method. Another study, of 1448 unrelated participants, was conducted to replicate the association between ADIPOQ gene and variable phenotypes of MetS with or without HTN.

Results

Among 962 subjects from family samples, the lowest plasma adiponectin value was observed in MetS with HTN component (9.3±0.47 µg/ml) compared with hypertensives (13.4±0.74 µg /ml) or MetS without HTN (11.9±0.60 µg/ml, P<0.05). The SNP rs1501299 (G276T) in ADIPOQ gene was found associated with the presence of HTN in MetS (odds ratio for GG+GT vs. TT = 2.46; 95% CI: 1.14-5.3, p = 0.02), but not rs2241766 (T45G). No association of ADIPOQ gene with HTN alone or MetS without HTN was observed. The significant association of the SNP rs1501299 (G276T) with the phenotype of presence of HTN in MetS was confirmed (odds ratio for GG+GT vs. TT = 2.15; 95% CI: 1.1–4.3) in the replication study.

Conclusions

ADIPOQ genetic variants were selectively and specifically associated with the concomitant presence of MetS and HTN, suggesting potential genetic linkage between MetS and HTN.