Prevention of postischemic reperfusion injury: The improvement of myocardial tissue blood flow after ischemia by terminal Nicorandil-Mg cardioplegia

We evaluated the preventive effect of postischemic reperfusion injury by Nicorandil-Mg cardioplegia given just prior to reperfusion as terminal cardioplegia. Twenty seven dogs were placed on cardiopulmonary bypass and the aorta was cross-clamped for 90 min under hypothermic (17–19°C) cardioplegic arrest. The canine hearts were divided into three groups: in group A (n=10) the hearts were reperfused without any treatment; in group B (n=9) the hearts received coronary perfusion with Nicorandil-Mg solution (Nic, 8 mg/l; Mg, 20 mEq/l; glucose, 50 g/l) for 2 min just prior to reperfusion; and in group C (n=8) the hearts received coronary perfusion with Nicorandil-Mg free solution (glucose, 50g/l). During and after ischemia, the myocardial tissue PCO₂ (t-PCO₂) was continuously monitored by an ion-sensitive field effective transistor (ISFET) sensor. In addition, the myocardial tissue blood flow (TBF), oxygen consumption, and lactate flux were then calculated at 5, 10, 20, and 40 min of reperfusion. In the initial reperfusion period, Group B showed an improved TBF compared to group A and C (at 5 min, group B was 42.7±11.9; group A was 29.4±11.2, P<0.025; and group C was 33.9±9.2% of the preischemic control level, P<0.05). T-PCO₂ in group B was significantly decreased at 5 min of reperfusion (group B, 127.5±22.5 42.5±9.7; group A, 117.5±23.0 85.2±17.4, P<0.001; group C, 122.3 mmHg 68.2±18.7 mmHg, P<0.01), and group B had a better metabolic recovery. These results suggest that terminal Nicorandil-Mg cardioplegia might reduce the rate of postischemic reperfusion injury.     

硫酸镁减轻缺血再灌注性兔脑损伤作用的实验研究

目的 :探讨硫酸镁对缺血再灌注兔脑损伤的作用。方法 :15只兔随机均分至 :对照组、缺血组和缺血+硫酸镁处理组。阻断兔脑血管 6分钟 ,诱导全脑缺血。缺血再灌注 3天后 ,分别用HE染色和TUNEL染色 ,检测海马CA1 区神经元密度和凋亡神经元密度。结果 :缺血 +硫酸镁处理组海马CA1 区正常神经元密度为 140 .5 2±16 .2 3个 mm ,显著高于缺血组 (P <0 .0 1) ;缺血神经元密度为 2 4.18± 3 .16个 mm ,显著低于缺血组 (P <0 .0 1) ;凋亡神经元密度为 18.40± 8.0 8个 mm ,显著低于缺血组 (P <0 .0 1)。结论 :硫酸镁具有减轻兔缺血再灌注性全脑损伤的作用 ,其作用机制可能同抑制缺血后神经元凋亡有关     

子痫发生相关因素的探讨

目的 探讨与子痫发生相关的临床因素。方法 回顾５年间孕产妇妊高征中先兆子痫的发生情况,探讨产前检查、妊高征的程度、硫酸镁用量与子痫发生的关系,并对子痫的先兆症状及其出现时进行分析。结果 子痫发生率占财期孕产女的０．５６％（５１／９１０１）,占妊高征的８．３３％（５１／６２）。产前检查次数与子亲的发生明显相关,中、重度妊高征中子痫的发生率较高,硫酸镁日用量小于１５ｇ时子痫的发生率升高明显。轻度妊高征     

镁离子对培养乳鼠心肌细胞羟自由基损伤的保护作用

目的　观察镁离子对培养乳鼠心肌细胞羟自由基损伤的保护作用。方法　本实验利用FeSO4/ H2O2 自由基产生体系,观察羟自由基作用于培养乳鼠心肌细胞,其上清液中乳酸脱氢酶(LDH) 和丙二醛( MDA) 含量的变化,以及镁离子对这种作用的影响。结果　(1) 羟自由基作用于培养乳鼠心肌细胞,其上清液中LDH 和MDA 的含量增加。(2) 镁离子能减少羟自由基引起的LDH 和MDA 含量的增加,且呈一定浓度、时间依赖关系。结论　羟自由基使培养乳鼠心肌细胞LDH 漏出增加及脂质过氧化终产物MDA 含量增加,镁离子对这一损伤有保护作用     

镁对脑缺血早期脑组织中谷氨酸及一氧化氮含量的影响

为研究镁在脑缺血早期对神经元保护作用的机制,用电凝法建立大鼠大脑中动脉缺血模型,在造模前给大鼠注射２０ｇ／Ｌ硫酸镁,观察镁对脑组织中谷氨酸（Ｇｌｕ）及一氧化氮（ＮＯ）含量的影响。结果显示,高浓度镁可明显降低脑缺血皮质中Ｇｌｕ、ＮＯ含量,在缺血组Ｇｌｕ、ＮＯ的峰值浓度分别为９．８７、４４．９７ｎｍｏｌ／ｇ,而在加镁组两者浓度分别为７．６８、３３．９２ｎｍｏｌ／ｇ。提示：镁对脑缺血早期神经元的保护作用与其降低脑组织中Ｇｌｕ及ＮＯ含量有关。     

氧化镁对高血压病人血压及胰岛素敏感性的影响

①目的　观察氧化镁对高血压病人血压及胰岛素敏感性的影响。②方法　将６０ 例原发性高血压病人随机分为两组。对照组给予硝苯地平缓释片治疗,治疗组加服氧化镁粉。治疗９０ｄ,观察血压、血清葡萄糖（ＳＧ）、胰岛素（ＩＮＳ）及Ｃ肽（ＣＰ）变化,并计算ＣＰ／ＩＮＳ及胰岛素敏感指数（ＩＳＩ）。③结果　治疗组治疗后收缩压（ＳＢＰ）、舒张压（ＤＢＰ）、ＩＮＳ及ＣＰ降低,ＩＳＩ增高,与治疗前比较差异有极显著性（ｔ＝ ４．１１～１７．５８,Ｐ均＜ ０．００１）;ＳＧ,ＣＰ／ＩＮＳ治疗前后比较差异无显著性（ｔ＝ ０．７８,１．３７,Ｐ＞ ０．０５）。对照组治疗后ＳＢＰ,ＤＢＰ降低（ｔ＝ １７．５０,１２．７０,Ｐ＜０．００１）;ＩＮＳ,ＣＰ,ＩＳＩ,ＳＧ及ＣＰ／ＩＮＳ均无显著变化（ｔ＝ ０．７８～１．５９,Ｐ 均＞ ０．０５）。与对照组比较,治疗组治疗后ＳＢＰ,ＤＢＰ,ＩＮＳ,ＣＰ降低及ＩＳＩ增高更显著（ｔ＝ ２．０９～８．８６,Ｐ＜ ０．０５,０．０１）;ＳＧ,ＣＰ／ＩＮＳ差异无显著性（ｔ＝ １．１９,０．５２,Ｐ＞ ０．０５）。④结论　氧化镁可有效降低高血压病人的血压,改善其胰岛素敏感性。     

Plasma ionized magnesium in tubular disorders with and without total hypomagnesemia

 Selective electrodes have been designed for determining plasma ionized magnesium. In kidney disease the relationship between ionized and total circulating magnesium is often altered. Hence plasma ionized magnesium (ETH 7025 membrane) was determined in 25 patients with primary renal tubular disorders; 6 patients had total hypomagnesemia. Total plasma magnesium was never reduced in the remaining 19 patients. Plasma ionized magnesium values were low in the 6 patients with total hypomagnesemia. In 18 of the 19 patients without total hypomagnesemia plasma ionized magnesium values were not reduced. Ionized hypomagnesemia was noted in a patient with normal total plasma magnesium in the context of hypercalciuric nephrocalcinosis of unknown origin. The study demonstrates an excellent concordance between plasma total and ionized magnesium in tubular disorders associated with total hypomagnesemia and a good concordance in tubular disorders that are not linked with total hypomagnesemia. The determination of circulating ionized magnesium is of little value in the diagnostic work-up of the vast majority of renal tubular disorders. The determination might perhaps disclose latent hypomagnesemia in nephrocalcinosis of unknown cause. Received: 20 March 1998 / Revised: 28 May 1998 / Accepted: 29 May 1998     

安宝治疗早产的临床研究

目的　探讨 β2 -肾上腺素能受体兴奋剂安宝抑制子宫收缩 ,治疗早产的临床效果。方法　对 91例先兆早产孕妇随机分为两组 ,分别静脉滴注安宝或硫酸镁。采用达到有效宫缩的最低浓度 ,适时停药 ,病情反复则间歇多次应用。结果　安宝首次用药达有效抑制宫缩的显效时间为 2h 40min ;延长孕期 2 9.3 4d ;足月分娩率 71.74% ;均极显著优于硫酸镁组 (P分别 <0 .0 0 1　 0 .0 1　 0 .0 1)。尚未发现严重毒副反应。结论　安宝抑制宫缩作用强显效快 ,治疗早产安全有效。     

果糖二磷酸钠镁对大鼠脑出血的保护作用

目的 :研究果糖二磷酸钠镁 (FDPM )对脑出血的保护作用。方法 :以胶原酶尾状核注射诱导大鼠脑出血模型 ,观察FDPM对大鼠脑出血后神经病学评分、脑含水量、血脑屏障通透性及脑组织病理改变的影响。结果 :FDPM 4 0 0mg·kg-1可降低脑出血大鼠神经病学评分 ,降低脑组织含水量 ,改善血脑屏障通透性 ,减轻脑组织病理改变 ,其作用强于相似剂量的 1,6 二磷酸果糖或硫酸镁 ,而FDPM 133mg·kg-1没有明显作用。结论 :FDPM对脑出血有显著的保护和治疗作用 ,其作用强于相似剂量的 1,6 二磷酸果糖或硫酸镁。     

丹参多酚酸B对高脂血症兔内皮功能的改善作用

目的研究丹参多酚酸 B(镁盐)对高脂血症兔受损的内皮结构以及内皮依赖性舒张功能的改善作用。方法选用新西兰纯种雄兔,随机分为正常组、高脂组及治疗组,通过血管多普勒的方法测定兔髂总动脉内血流平均峰值速度(APV)的变化以评价内皮依赖性血管舒张功能;取胸主动脉标本分别送电镜、光镜检查以观察各组动物内皮细胞的形态学特征。结果形态学检查显示丹参多酚酸 B(镁盐)可减轻高脂血症所致的血管壁结构的损害;血管多普勒检测显示注射乙酰胆碱后正常组、高脂组、治疗组的 APV 比值分别为1.10±0.20、1.65土0.69、1.15±0.37,治疗组与高脂组比较,差异有显著性(P<0.05),表明丹参多酚酸 B(镁盐)可改善异常的内皮依赖性舒张功能。结论丹参多酚酸 B(镁盐)可改善高脂血症所致的内皮结构以及内皮依赖性舒张功能的异常。