后循环缺血与眩晕

后循环又称椎基底动脉系统，由椎动脉、基底动脉和大脑后动脉（posterior cerebral artery，PCA）组成，主要向脑干、小脑、丘脑、枕叶、部分颞叶等结构供血。后循环缺血（posterior circulation ischemia,PCI）是常见的缺血性脑血管病。与前循环缺血一样，PCI也可按缺血程度和持续时间的不同分为短暂性脑缺血发作（transient ischemic attack,TIA）和脑梗死。其同义词包括椎基底动脉系统缺血、后循环TIA和脑梗死、椎基底动脉疾病、椎基底动脉血栓栓塞性疾病。     

^1H-magnetic resonance spectroscopy screening for animals with acute cerebral infraction suitable forthrombolytic therapy

BACKGROUND: As a non-invasive technique which can provide comprehensive biological information, 1H-magnetic resonance spectroscopy (1H-MRS) may provide valuable reference data for irreversible recovery or reversible changes in ischemic tissue after stroke. OBJECTIVE: To monitor and evaluate the effect of the urokinase thrombolytic therapy after experimental acute cerebral ischemia by 1H-MRS technology and investigate its adaptability. DESIGN: Randomly controlled animal study. SETTINGS: Shenzhen Hospital of Peking University and National Key Laboratory of Pattern and Atom & Molecular Physics, Wuhan Physics and Mathematics Institute, Chinese Academy of Science. MATERIALS: Eleven healthy adult Sprague-Dawley (SD) rats, weighing 260–300 g and of both genders, were supplied by Experimental Animal Center of Tongji Medical Collage, Huazhong University of Science and Technology [SCXK (e) 2004-007]. 4.7T superconducting nuclear magnetic resonance meter was provided by Brucker Company. METHODS: The experiment was carried out in Shenzhen Hospital of Peking University and National Key Laboratory of Pattern and Atom & Molecular Physics, Wuhan Physics and Mathematics Institute, Chinese Academy of Science from August 2003 to December 2005. ① The rats were randomly divided into 30-minute self-thrombo-embolism group (n =6) and 60-minute self-thrombo-embolism group (n =5). Six rats in 30-minute self-thrombo-embolism group were occluded with clot embolus for 30 minutes and 5 rats in 60-minute self-thrombo-embolism group were occluded for 60 minutes. 10 000 U/kg urokinase was dissolved in 2 mL saline and the operation lasted for 5 minutes. ② 1H-MRS was performed before thrombolysis and at 3 hours and 24 hours after successful embolization. The metabolic changes of N-acetyl-L-aspartic acid (NAA)/phosphocreatine (PCr) + creatine (Cr), choline phosphate (Cho)/PCr+Cr and lactic acid (Lac)/PCr+Cr in the region of interests were analyzed. ③ The T2W image was conducted 24 hours after the thrombolytic therapy with TR=500 ms and TE=25 ms. ④ The subjects were sacrificed immediately after 1H-MRS and the brain tissues were cut into pieces and stained with HE method; in addition, pathological changes were observed under optic microscope. MAIN OUTCOME MEASURES: ① Metabolic changes of NAA/PCr+Cr, Cho/PCr+Cr and Lac/PCr+Cr in the region of interests; ② T2W image at 24 hours after the thrombolysis; ③ pathological observation of brain tissue. RESULTS: Eleven rats were all involved in the final analysis. ① Metabolic changes in the region of interests : In 30-minute self-thrombo-embolism group, the Lac peak emerged immediately after the embolism, but the ischemic zone decreased 3 hours after the thrombolytic therapy (0.252±0.01, 0.603±0.01, P < 0.01). Lac/(PCr+Cr) ratio was 0.290±0.01 at 24 hours after thrombolysis, which was higher than that at 3 hours after thrombolysis (P < 0.01). The NAA/ (PCr+Cr) ratio decreased significantly at 3 hours after the thrombolysis as compared with that before thrombolysis (0.922±0.16, 1.196±0.01, P < 0.05). In 60-minute self-thrombo-embolism group, the Lac/(PCr+Cr) ratio was higher at 3 hours after thrombolysis than that before thrombolysis (0.846±0.12, 0.601±0.11, P < 0.05) and the NAA/(PCr+Cr) decreased at 3 hours after the embolism. Fluctuation of NAA/ (PCr+Cr) ranged from 0.68 to 0.75 before thrombolysis and from 0.71 to 0.75 at 3 hours after thrombolysis. ② T2W image: T2W image showed that 2 subjects in 30-minute self-thrombo-embolism group whose Lac/NAA was higher than 0.7 suffered from intracranial hemorrhage. This meant that the subjects with Lac/NAA > 0.7 were more likely to suffer from intracranial hemorrhage. ③ Histological and morphological examinations: Optic microscope demonstrated that interspace surrounding nerve cells was widened at ischemic center; neurons were swelling; nucleus was stained lightly; pyknosis and mesenchymal edema were mainly observed in lateral cortex of brow and vertex and in lateral part of corpus striatum. CONCLUSION: ①Compound parameters in ischemic area before thrombolysis should be regarded as an important predicting marker for thrombolytic therapy, effect evaluation and termination. ② 1H-MRS combining with other imaging technique is a detecting way for screening cases who are suitable for thrombolytic therapy.     

医学界对文迪雅的安全信息表现冷静——专家表示需要更多的评估

最近一份发布于《新英格兰医学》杂志的研究报告指出,治疗2型糖尿病的药物文迪雅(Avandia,化学名罗格列酮)会使患者发生心脏病发作的几率增加。这一     

缺氧诱导因子-lα与脑缺氧缺血性损伤

缺氧诱导因子-lα（hypoxia-inducible factor-1alpha，HIF-lα）是近来发现的广泛存在于哺乳动物和人体内的一种缺氧应答调控因子，在调节缺氧诱导的基因表达中起关键性作用。它可调节表达多种靶基因如血管内皮生长因子、促红细胞生成素等，对改善脑缺氧缺血后能量代谢障碍、促进脑血流动力学恢复、抑制兴奋性氨基酸毒性、减少细胞凋亡等起重要作用。通过进一步对HIF-lα及其靶基因的研究，可能为临床治疗脑缺氧缺血性损伤提供了一种新的治疗策略。     

急性缺血性卒中的亚低温治疗研究进展

脑缺血神经细胞损伤的保护措施一直是临床和基础研究的重点。但迄今为止,仍然缺少令人满意的措施。缺血性脑血管病的发病机制复杂,亚低温作为一种脑保护疗法,可干预脑缺血的多个病理生理学环节,对脑缺血及再灌注损伤起到保护作用。目前国际医学界将低温划分为轻度低温(33~35℃)     

Ximelagatran和华法林对心房颤动患者卒中二级预防的比较

背景与目的患有非瓣膜性心房颤动或曾患卒中或短暂性脑缺血（TIA）者具有复发性卒中的高度危险性。我们研究Ximelagatran对曾患卒中或TIA患者的作用是否不亚于华法林。     

低分子肝素钠治疗短暂性脑缺血发作效果观察

短暂性脑缺血发作(TIA)是由颅内血管病变引起的一过性或短暂性、局灶性脑或视网膜功能障碍。临床症状一般持续10～15分钟,多在1小时内,不遗留神经功能缺损症状和     

中西医结合治疗痛风性关节炎73例疗效观察

痛风是由体内嘌呤代谢紊乱所致的一种疾病。其临床特点为高尿酸血症和由此引起的痛风性关节炎反复发作、痛风石沉积、痛风性肾脏病变、痛风性心血管病变等多种病症。尤其是以痛风性关节炎反复发作为多见。痛风性关节炎为临床中老年的常见疾病。近年来由于生活水平提高,食谱变化、发病率有明显增高。笔者近3年来以中西医结合治疗痛风性关节炎73例,取得明显疗效。总结如下。     

口咽通气管在癫痫持续状态急救中的应用

癫痫持续状态是指一次癫痫发作持续30分钟以上，或连续多次发作、发作间期意识或神经功能未恢复至通常水平。病人常因牙关紧闭、呼吸道分泌物增加，导致舌咬伤、窒息等危害病人的生命，我科通过给病人放置口咽通气管，有效避免了上述病症。     

IPC、IT与EPO在脑缺血耐受发生机制中的作用

一次或多次短暂的、非致死性的脑缺血刺激，即所谓缺血预处理（isehemic precondition，IPC），能让脑组织对随后发生严重的、甚至致死性的缺血产生耐受，这就是脑对抗缺血的一种自身性保护现象，又称为缺血耐受（isehemic tolerance phenomenon，IT）。然而，将IPC人为地直接用于有脑缺血隐患的人体上显然是不现实的。如果将研究证实在IT过程中确有作用的内源性神经保护介质及其制剂提供给病人，触发IPC，也许是切实可行的。最近有人提出了药物预处理、化学预处理等概念，试图通过模拟体内具有神经保护作用的内源性物质，发挥IT保护脑细胞作用。