同型半胱氨酸与血管成形术后新内膜增生的研究进展

同型半胱氨酸是一种含硫的非必需氨基酸 ,其在血管动脉粥样硬化中的作用已得到大量资料证实。近来发现其有促进血管成形术后血管内膜增生的作用 ,从而促进血管再狭窄。高同型半胱氨酸不仅具有抑制血管内皮损伤后内皮修复的作用 ,而且有促进内皮下血管平滑肌细胞增殖及迁移的作用 ,这可能是其促进血管成形术后新内膜增生的机制。     

急性心肌梗死血管内皮生长因子变化的研究进展

血管内皮生长因子 (VEGF)也称血管通透因子 ,是 1989年Ferrara等分离、纯化出的一种细胞因子 ,它对血管内皮细胞具有高度特异性促有丝分裂作用 ,目前已知多种生长因子和细胞因子具有促进血管生成的作用。然而在众多的血管生成因子中 ,VEGF是最有力的血管生成因子 ,它通过和血管内皮细胞的特异性受体结合 ,具有强大的促内皮增殖、促血管生成作用。其它血管生成因子的血管生成作用是全部或部分通过增强VEGF的表达及生成作用实现的[1] 。1　VEGF的生物学特性VEGF的生物学特性主要表现在两方面 :增加微血管的通透性和特异性与血管内皮…     

肺血管内皮细胞与低氧性肺血管收缩

研究表明,低氧性肺血管收缩的发生不仅取决于对肺血管床起作用的血管活性物质的量,而且更取决于缩血管物质/扩血管物质的比例。肺血管内皮细胞在调节到达平滑肌受体的血管活性物质的量及其比例方面有极为重要的作用。本文介绍其功能及肺血管内皮受损在低氧性肺血管收缩中的可能作用。     

衰老与内皮依赖血流介导的血管扩张功能异常

内皮是血流与血管平滑肌之间的生理屏障。由于其解剖部位 ,内皮是心血管危险因子作用的最先目标。正常内皮细胞可释放血管活性物质调控血管张力。内皮功能异常可导致血管矛盾运动。内皮细胞可产生许多缩血管舒血管物质 ,如 :一氧化氮 ,Ｐ物质 ,内皮素 ,血管紧张素 ,前列腺素 ,血栓素Ａ2及自由基 ,参与心血管病理生理改变。由于一氧化氮扩张血管及抑制血小板作用 ,其对血管功能具有重要的保护作用。内皮细胞可通过其自分泌 ,旁分泌甚至内分泌途径而发挥其作用。完整的内皮细胞通过其分泌的活性物质可影响血管细胞的生长增殖 ,血小板粘附聚集…     

衰老与内皮依赖血流介导的血管扩张功能异常

内皮是血流与血管平滑肌之间的生理屏障。由于其解剖部位 ,内皮是心血管危险因子作用的最先目标。正常内皮细胞可释放血管活性物质调控血管张力。内皮功能异常可导致血管矛盾运动。内皮细胞可产生许多缩血管舒血管物质 ,如 :一氧化氮 ,Ｐ物质 ,内皮素 ,血管紧张素 ,前列腺素 ,血栓素Ａ2及自由基 ,参与心血管病理生理改变。由于一氧化氮扩张血管及抑制血小板作用 ,其对血管功能具有重要的保护作用。内皮细胞可通过其自分泌 ,旁分泌甚至内分泌途径而发挥其作用。完整的内皮细胞通过其分泌的活性物质可影响血管细胞的生长增殖 ,血小板粘附聚集…     

血管紧张素的心内生成及其生理作用

肾素和血管紧张素的遗传密码在心脏的所有部位都可被表达,此为心内合成这些蛋白质的先决条件。跳动的哺乳动物心脏具有使血管紧张素I转换成血管紧张素II的生理功能。血管紧张素II的正性肌力作用是基于直接的肌性营养作用以及时交感神经传递的易化作用。局部产生的血管紧张素可能是发生再灌注心律失常的主要因素,转换酶抑制剂在充血性心力衰竭中的独特作用,提示除了其全身血流动力学的作用之外,还有直接的心脏作用。     

激动κ阿片受体在改善高脂血症引起的血管内皮功能失调中的作用机制探讨

高脂血症引起的血管内皮功能失调是引起代谢综合征及多种心血管疾病并发症的关键环节之一。高脂血症造成血管内皮损伤的机制包括导致血管内皮分泌的血管舒、缩因子平衡失调、促进炎症反应和促进血管内皮氧化应激等。同时,激动κ阿片受体（κ-opioid receptor,κ-OR）在多种心血管疾病研究中被证实可以起到明确的心血管保护作用,但关于激动κ-OR在高脂血症引起的血管内皮功能失调中的作用仍有待研究。本文综述了高脂血症导致的血管内皮损伤和激动κ-OR所起的血管内皮保护作用的研究进展,探讨了激动κ-OR在改善高脂血症引起的血管内皮功能失调中的作用,为进一步研究激动κ-OR所起的作用提供了思路。     

由血管紧张素(1-7)重新认识RAS系统

对血管紧张素 (1- 7)的研究使我们对肾素 -血管紧张素系统 (RAS)有了更全面的认识。血管紧张素 (1-7)通过特异性的受体发挥生理作用。血管紧张素Ⅰ和血管紧张素Ⅱ经过特异的肽链内切酶变为血管紧张素 (1 -7) ,再经血管紧张素转换酶作用降解为无活性的血管紧张素 (1- 5 )。血管紧张素 (1- 7)具有抗增殖、扩张血管、抗氧化应激及促进纤溶的作用。     

急性脑梗死患者血清与脑脊液中血管内皮细胞生长因子含量的变化

血管内皮细胞生长因子(vascular endothelial growth factor,VEGF)是一种特异性作用于血管内皮细胞、具有分裂原作用、促进血管生成和增强血管通透性作用的细胞因子。对血管闭塞性疾病具有促进侧支循环建立的作用。我们观察脑梗死患者血清与脑脊液(CSF)中VEGF含量的变化,探讨VEGF与脑梗死的关系。     

尾加压素Ⅱ对血管的复杂调节及其机制

尾加压素Ⅱ是最近发现的一种新的血管活性物质，其对血管调节的作用与经典血管活性肽如内皮素、血管紧张素、肾上腺髓质素等比较明确的作用不一致，在不同机制作用下，可以产生强的血管收缩作用，还可以产生血管舒张作用，这种对血管的双向复杂的调节，提示其有着更为复杂的生理和病理生理意义，本文简略综述了其血管的复杂调节作用及其可能机制。     

甘露聚糖、壳聚糖、α-酸性糖蛋白和姜黄素对脂蛋白(a)和去唾液酸脂蛋白(a)代谢影响的对比分析

分析多糖和姜黄素对脂蛋白 (a)和去唾液酸脂蛋白 (a)代谢的影响 ,从刺猬腋下静脉注入甘露聚糖、壳聚糖、α -酸性糖蛋白和姜黄素 ,2min后注射12 5I-脂蛋白 (a)或12 5I-去唾液酸脂蛋白 (a) ,1h后处死动物 ,测定血、肝、肾、脾、胆汁和肾上腺的同位素含量。结果发现 ,脂蛋白 (a)去唾液酸后能大量进入肝脏 ,加速在体内的分解代谢 ,使血中浓度迅速降低。α -酸性糖蛋白抑制组织对脂蛋白 (a)和去唾液酸脂蛋白 (a)的摄入 ,使血中脂蛋白 (a)和去唾液酸脂蛋白 (a)含量显著增高。壳聚糖和姜黄素增加肝脏和肾上腺对脂蛋白 (a)的摄取 ,使血中脂蛋白 (a)含量略降低 ,但对去唾液酸脂蛋白 (a)代谢无明显影响。甘露聚糖增加脾脏对脂蛋白 (a)的摄取 ,减少胆囊中脂蛋白 (a)含量 ,但增加肾脏和胆囊对去唾液酸脂蛋白 (a)的摄取 ,降低肾上腺对去唾液酸脂蛋白 (a)的摄取。结果提示 ,脂蛋白 (a)去唾液酸后能使脂蛋白 (a)分解代谢加快 ,脂蛋白 (a)分子中的唾液酸在结构稳定中起重要的作用。α -酸性糖蛋白抑制脂蛋白 (a)和去唾液酸脂蛋白 (a)代谢 ,而壳聚糖和姜黄素则促进脂蛋白 (a)代谢     

甘露聚糖、壳聚糖、α-酸性糖蛋白和姜黄素对脂蛋白(a)和去唾液酸脂蛋白(a)代谢影响的对比分析

分析多糖和姜黄素对脂蛋白（ａ）和去唾液酸脂蛋白（ａ）和去唾液酸脂蛋白（ａ）代谢的影响,从刺猥腋下静脉注入甘露聚糖、壳聚糖、α－酸性糖蛋白和姜黄素,２ｍｉｎ后注射＾１２５Ｉ－脂蛋白（ａ）或＾１２５Ｉ－去唾液酸脂蛋白（ａ）,１ｈ后处死动物,测定血、肝、肾、脾、胆汁和肾上腺的同位素含量。结果发现,脂蛋白（ａ）去唾液酸后能大量进入肝脏,加速在体内的分解代谢,使血中浓度迅速降低。α－酸性糖蛋白抑制组织对脂蛋白（ａ）和去唾液酸脂蛋白（ａ）的摄入,使血中脂蛋白（ａ）和去唾液酸脂蛋白（ａ）含量显著增高。壳聚糖和姜黄素增加肝脏和肾上腺对脂蛋白（ａ）的摄取,使血中脂蛋白（ａ）含量略降低,但对去唾液酸脂蛋白（ａ）代谢无明显影响。甘露聚糖增加脾脏对脂蛋白（ａ）的摄取,减少胆囊中脂蛋白（ａ）含量,但增加肾脏和胆囊对去唾液酸脂蛋白（ａ）的     

Corticotropin-induced reduction of plasma lipoprotein(a) concentrations in healthy individuals and hemodialysis patients: relation to apolipoprotein(a) size polymorphism

Lipoprotein(a) [Lp(a)], a strong independent cardiovascular risk factor, consists of the unique apolipoprotein(a) [apo(a)] covalently linked to a low-density lipoprotein particle. Apo(a) contains a widely differing number of the plasminogen-like kringle IV, a size polymorphism that is codominantly inherited. In addition to powerful genetic control, renal failure is known to influence the plasma Lp(a) concentration. There is still a lot to be learned about the mode and site of catabolism of Lp(a), and there is no readily applicable Lp(a)-lowering treatment available. Therefore, it was of interest to study further the Lp(a)-lowering effect of corticotropin (ACTH) that has been demonstrated in small studies. The main purpose of the present study was to investigate the influence of ACTH on different apo(a) isoforms. Short-term treatment with ACTH decreased the plasma Lp(a) concentration in all 26 study participants. The two study groups (12 healthy individuals and 14 hemodialysis patients) responded similarly, with a median decrease in plasma Lp(a) of 39% and 49%, respectively. In subjects with two clearly separable apo(a) bands, apo(a) phenotyping and densitometric scanning of the bands before and after treatment with ACTH revealed a change in the proportion of apo(a) isoforms, ie, a shift toward the isoform with lower molecular weight. This was observed in seven of nine investigated subjects (four of five healthy individuals and three of four hemodialysis patients).     

脂蛋白(a)的研究进展

脂蛋白(a)是动脉粥样硬化形成与进展的高危因素,外周血中高浓度的脂蛋白(a)已成为冠心病公认的预测因子。由于它主要受遗传调控,饮食、运动、生活方式、传统降脂药物等对脂蛋白(a)水平的影响很小。随着研究的深入,脂蛋白(a)的代谢、致病机制和危害逐渐被人们了解,氧化修饰后的脂蛋白(a)具有更强的致动脉粥样硬化作用。此外,可降低脂蛋白(a)的新型降脂药物已经被研发出来,它们降低脂蛋白(a)的强度和作用靶点各不相同,对疾病的预后的影响也仍有待观察。本文就脂蛋白(a)的代谢、遗传调控、氧化修饰、临床干预手段等研究进展作一综述。     

Effect of cardiopulmonary bypass and heparin on plasma levels of Lp(a) and Apo(a) fragments

Fragments of apolipoprotein(a) [apo(a)], the distinctive glycoprotein of lipoprotein(a) [Lp(a)], are present in human plasma and urine and have been implicated in the development of atherosclerosis. The mechanism responsible for the generation of apo(a) fragments in vivo is poorly understood. In this study, we examined the plasma levels of Lp(a) and apo(a) fragments [or free apo(a)] and urinary apo(a) in 15 subjects who underwent cardiac surgery necessitating cardiopulmonary bypass. We also measured the plasma concentration and activity of polymorphonuclear elastase, an Lp(a)-cleaving enzyme in vitro, and plasma levels of C-reactive protein. Despite a marked activation of polymorphonuclear cells and a pronounced inflammatory response, as documented by an 8-fold and a 35-fold increase in plasma levels of polymorphonuclear elastase and C-reactive protein, respectively, the proportion of plasma free apo(a) to Lp(a) and urinary excretion of apo(a) remained unchanged over a 7-day period after surgery, and polymorphonuclear elastase activity remained undetectable in plasma. No fragmentation of apo(a) was observed ex vivo in plasma samples collected before and after surgery. These data indicate that in this model, apo(a) is not fragmented in plasma and are consistent with the hypothesis that apo(a) fragments result from a constitutively active tissue mechanism that is not modified by cardiac surgery with cardiopulmonary bypass.     

Diverticular fecalith in scleroderma simulating colonic neoplasm: Report of a case

This is a report of a patient with the CRST syndrome, a mild variant of scleroderma consisting of calcinosismraynaud's phenomenon, sclerodactyly, and telangiectasia. Typical changes of scleroderma were present in the extremities, esophagus, duodenum and colon. In addition, there was a polypoid filling defect in a colonic diverticulum due to a fecalith. The radiologic appearance at first resembled a colonic neoplasm, although its location within a diverticulum and its speckled appearance suggested the possibility of a fecalith. This was confirmed at colonoscopy, which disclosed numerous wide-mouthed diverticula, with inspissated fecal material projecting from several diverticula. In patients with scleroderma and polypoid filling defects in the colon, the possibility of a fecalith within a diverticulum should be considered. Where the radiologic study is inconclusive, colonoscopy may provide a definitive diagnosis.     

Ovarian carcinoma as a cause of Zollinger-Ellison syndrome. Natural history, secretory products, and response to provocative tests

Zollinger-Ellison syndrome is usually caused by a gastrin-secreting tumor in or near the pancreas. We describe a patient in whom an ovarian cystadenocarcinoma was the cause of the syndrome. The patient presented with a short history of peptic ulceration and development of a large pelvic mass. Investigations demonstrated a basal acid output of 37.8 mEq/h and a maximal acid output of 36.0 mEq/h, and the plasma concentration of gastrin was 830 pg/ml (normal less than 100). Secretin and calcium infusion tests were positive, and a meal test was compatible with Zollinger-Ellison syndrome. Imaging studies demonstrated a normal liver and pancreas but a large cystic right ovarian mass. Resection of the mass resulted in a marked reduction in gastric acid output, a fall in plasma gastrin concentration to normal, negative calcium and secretin tests, and a normal (positive) meal test. Histology of the mass showed it to be a mucinous cystadenocarcinoma. The tumor stained with immunoperoxidase technique was positive for gastrin, and the cyst fluid contained high concentrations of gastrin and calcitonin. One year later, the patient has no biochemical or imaging evidence of tumor. Ovarian, gastrin-producing tumors and pancreatic gastrinomas cannot be distinguished by provocative tests, and negative imaging studies do not exclude a pancreatic tumor. Patients with an ovarian mass and Zollinger-Ellison syndrome should have a bilateral oophorectomy and a careful exploration of the pancreatic area.     

Clinical evaluation of different fluid-filled systems for oesophageal manometry.

In a clinical study of oesophageal manometry with fluid-filled catheters, both a non-perfused system and a perfused system with a syringe pump have been compared to a system with a low-compliance perfusion pump, which served as a reference. Significantly lower values of motility amplitudes, motility derivatives, and partly of LES pressures, and a time delay of up to 0.5 sec of the amplitude maximum were obtained with the non-perfused system and the system with a syringe pump in comparison to the low-compliance system. Since the oesophageal function can be erroneously evaluated by use of a non-perfused system or a perfused system with a syringe pump, such systems cannot be recommended for clinical use.     

Disposable versus reusable biopsy forceps. A prospective cost analysis in the gastrointestinal endoscopy unit of the Dijon University Hospital]

AIMS: The goal of this study was to compare the cost of a biopsy session performed with a disposable and a reusable endoscopic biopsy forceps.MATERIAL AND METHODS: Over a 10-month period, 15 new reusable forceps (10 gastric and 5 colonic) were prospectively tracked. A biopsy session performed with a reusable forceps included its current purchase price, the sterilization cost and the number of uses. A biopsy session performed with a disposable forceps was calculated with its current purchase price and its incineration cost.RESULTS: At the end of the study, only one reusable forceps had broken and the number of uses was 65. The cost of a biopsy session performed with a gastric reusable forceps was euro 7.52 (including euro 1.92 of sterilization cost) and euro 8.67 for a reusable colonic forceps (with the same sterilization cost). The cost of a biopsy session performed with a gastric or a colonic disposable forceps was euro 11.98. From 44 uses for a colonic forceps and 37 uses for a gastric one, a biopsy session performed with a reusable forceps was already cheaper.CONCLUSION: In this study, a biopsy session performed with a reusable forceps was less expensive than with a disposable one. However, the extra cost generated by the disposable forceps may be offset by an easier inventory control and the reduction of the cross contamination risk.     

Distribution and rearrangements of alleles of c-Ha-ras-1 protooncogene and their correlation with the development of lung, ovarian and thyroid cancers

The protooncogene c-Ha-ras-1 locus in 84 cancer patients was examined for allelic restriction fragment length polymorphism. The distribution of four common c-Ha-ras-1 alleles (a1, a2, a3 and a4) in lung, ovarian and thyroid cancer patients was analyzed. In approximately half (8 out of 15) of lung and ovarian carcinomas possessing the a4 allele, alterations of the c-Ha-ras-1 locus (deletion of allele with the shorter fragment length, amplification of a4 allele, change of allele fragment length) were detected as compared to 2 cases of rearrangement out of 40 tumors lacking the a4 allele. An increased a4 allele frequency was found in individuals with lung and ovarian tumors as compared to controls presented in literary data and thyroid cancer patients. On the other hand, homozygosity for the a2 locus resulting from the deletion of another allele, and increased a2 allele frequency in thyroid cancer patients were observed. Thus the a4 and a2 alleles of c-Ha-ras-1 may perhaps be viewed as genetic markers of predisposition to lung, ovarian and thyroid cancer, respectively, in combination with other clinical parameters.