The circadian rhythm of blood pressure and the effect of sa lt intake in salt-sensitive subjects

Objective To investigate the effect of salt intake on the circadian rhythm of blood pressure and the characteristics of ambulatory blood pressure (ABP) in salt-sensitive (SS) subjects. Methods Twenty-three normotensive subjects and forty-three patients with essential hypertension were included in this study.Salt sensitivity was determined with a chronic dietary salt loading test and an acute venous saline loading test, respectively.24-hour ABP measurements were performed twice in normotensive subjects when they were on a high salt diet and when they had a low salt diet.Blood and urine samples were collected for measurement of plasma norepinephrine concentration (PNE), plasma renin activity (PRA), angiotensin Ⅱ, aldosterone, erythrocyte sodium content and urinary sodium excretion.24-hour ABP readings were also obtained in patients with essential hypertension when antihypertensive drugs were discontinued for at least 2 weeks. Results High salt intake attenuated the circadian rhythm of blood pressure in SS normotensive subjects, and the nocturnal decline in blood pressure was smaller in SS patients with essential hypertension than in salt-resistant (SR) patients.The level of PNE was higher and the suppression of PRA was smaller in SS subjects than in SR subjects when they had a high salt diet, and the urinary sodium excretion decreased and the erythrocyte sodium content increased significantly in SS subjects on high salt intake. Conclusions High salt intake caused an abnormal circadian rhythm of blood pressure in SS subjects.The blunted nocturnal decline in blood pressure may be a characteristics of SS patients with essential hypertension.     

孕妇血浆次黄嘌呤水平预测胎儿宫内窘迫缺氧程度的研究

探讨孕妇血浆次黄嘌呤对胎儿、新生儿缺氧状况的预测可能及价值 ,应用方法是采用改良酶学法检测 40例产前诊断为胎儿宫内窘迫的孕妇及所生新生儿血浆次黄嘌呤浓度 ,以同期 40例产前无胎儿宫内缺氧的孕妇及新生儿为对照 ,同时进行当前常用缺氧指标的评定及临床观察。结果显示 :缺氧组孕妇及其新生儿脐血浆Hx明显高于对照组 (P<0 .0 0 1 )。孕妇血浆 Hx与新生儿脐血浆 Hx呈明显正相关 (r=0 .6 2 6 ,P<0 .0 1 )。以对照组 x± t0 .1 0 s为参照 ,孕母及其新生儿血浆 Hx与常用围产期缺氧 8项指标比较诊断指数分别为 :0 .7、0 .775明显高于其它指标。因此 ,孕妇血浆 Hx可做为围产期缺氧早期监测、防治有很大临床价值的指标 ,值得进一步研究与应用     

盐敏感性高血压患者的钠代谢与钠泵α_1亚单位基因点突变

在盐敏感性与高血压之间 ,钠泵基因缺陷所导致的钠离子转运异常可能起着联系环境 (盐 )与遗传的桥梁作用。近年的研究表明 ,盐敏感者有细胞膜离子转运缺陷及Ｏｕａｂａｉｎ抵抗现象。动物实验研究表明 ,盐敏感性高血压动物个体钠泵活性受抑、Ｏｕａｂａｉｎ抵抗及肾排钠障碍与钠泵基因突变有关。目前尚无人类盐敏感性高血压与钠泵基因突变的资料。本文采用ＰＣＲ ＳＳＣＰ及序列分析技术检测盐敏感者钠泵α1亚单位基因Ｏｕａｂａｉｎ结合位点区域是否存在点突变 ,同时检测盐敏感者钠代谢改变 ,探讨二者之间的关系。一、资料与方法1 对象选择…     

高血压伴胰岛素抵抗降压调糖治疗的干预研究

目的观察硝苯地平控释片及二甲双胍对高血压伴胰岛素抵抗(IR)患者相关参数的影响.方法将57例高血压伴IR患者随机分为单纯降压组及降压调糖组,前者给予硝苯地平控释片,后者给予硝苯地平控释片加二甲双胍片.治疗前、后行口服糖耐量试验、胰岛素释放试验及动态血压监测,观察治疗前、后及两组间血糖、血胰岛素、胰岛素敏感指数及动态血压的变化.结果用药后单纯降压组及降压调糖组空腹血糖、空腹胰岛素及2h胰岛素均无显著性下降.降压调糖组2h血糖下降显著,与单纯降压组对比有显著性差异[(6.03±3.47)mmol/L比(8.98±5.27)mmol/L,P＜0.05].两组用药后胰岛素敏感指数均有显著升高(P＜0.05),以降压调糖组为著[(11.14±0.34)×10-3比(10.09±0.57)×10-3,P＜0.05].两组均可降低白天血压,对夜间血压仅降压调糖组可显著降低夜间舒张压(862±11.8)mmHg比(76.2±9.7)mmHg,P＜0.05],与单纯降压组对比有显著性差异[(762±9.7)mmHg比(80.2±12.4)mmHg,P＜0.05].两组降压药用量相等时,单纯降压组疗效为88.89%,降压调糖组为96.67%,显著高于单纯降压组;两组降压疗效无显著性差异时,单纯降压组降压药用量明显高于降压调糖组.结论硝苯地平控释片对血糖、血胰岛素无不良影响,可轻度改善IR;二甲双胍与硝苯地平控释片联合应用可明显改善IR,且能降低降压药的用量;较小剂量的降压药加二甲双胍比应用较大剂量降压药能更显著地改善IR,推测IR可能不是高血压的后果,而是高血压的发病原因之一或与高血压平行发生;二甲双胍与硝苯地平控释片联合应用在治疗高血压伴IR方面值得推荐.2h血糖或夜间舒张压下降可作为观察IR改善的指标之一.     

α-内收蛋白Gly460Trp变异与中国汉族人原发性高血压的相关性研究

目的：探讨内收蛋白α亚单位（α－内收蛋白）变异与中国汉族人原发性高血压发病的关系。方法：以１８３例汉族原发性高血压患者和１２９名血压正常者为研究对象,从外周血白细胞中提取基因组ＤＮＡ,采用聚合酶链式反应、单链构象多态性分析及ＤＮＡ序列测定等分子生物学技术,对α－内收蛋白基因第１０个外显子部分序列进行基因变异检测,并对身高、体重、血压等临床资料进行测定。结果：发现在α－内收蛋白基因第１０外显子的第６１４位核苷酸存在Ｇ被Ｔ替换的变异,使其氨基酸序列第４６０位的甘氨酸（Ｇｌｙ）被色氨酸（Ｔｒｐ）取代（Ｇｌｙ４６０Ｔｒｐ）,Ｇｌｙ／Ｇｌｙ、Ｇｌｙ／Ｔｒｐ和Ｔｒｐ／Ｔｒｐ３种基因型人群中的分布符合Ｈａｒｄｙ－Ｗｅｉｎｂｅｒｇ遗传平衡。该变异在原发性高血压患者与血压正常者中的频率分布差异无显著性（Ｐ＞０．０５）,３种基因型