DWI多b值水通道蛋白分子成像在肝纤维化早期诊断的价值

目的：探讨磁共振弥散加权成像（MR diffusion weighted imaging,MR-DWI）多b值水通道蛋白（Aquaporin,AQP）分子成像技术在肝纤维化早期诊断的价值.方法：应用乙酰唑胺作为水通道蛋白抑制剂,将对照组及肝纤维化模型组大鼠分别于乙酰唑胺静脉注射抑制前后进行常规MRI及DWI扫描.DWI扫描多b值包括0～4 500 s/mm2共18个不同b值,先按照常规方法获得“标准”表观弥散系数（ADC）值,然后再分别以200、1 500作为界值将其分为低、中和高b值.以病理学肝纤维化分期将大鼠分为S0、S1、S2、S3、S4期,比较低、中、高b值下,不同纤维化分期大鼠肝脏ADC值,并观察同一分期大鼠乙酰唑胺抑制前后,肝脏组织细胞膜上AQP表达量和活性变化情况.结果：“标准”ADC值在各分期之间均无显著性差异.在肝纤维化早期,随着肝纤维化程度的进展,肝脏组织细胞膜上AQP1表达相应增加.乙酰唑胺抑制前,在高b值下,S0期ADC值显著低于S3、S4期（P＜0.05）,其余各组比较均无明显统计学差异;但乙酰唑胺抑制后,高b ADC值比较,S0与S1比较无明显统计学差异,S0与其他各期比较、S1与S2、S1与S3/S4比较,均有明显统计学差异（均P＜0.05）.各组内乙酰唑胺抑制前后自身比较,SO、S1期抑制率分别为15.5％、16.0％,S2期抑制不明显1.9％,S3＋S4期为11.7％.结论：初步实验表明,常规方法获得“标准”ADC值并不能发现肝脏纤维化早期病变,也不能有效对其分期.磁共振DWI多b值扫描,主要是高b值下ADC值变化与肝脏细胞膜上AQP表达相关,该技术可以用于评价早期肝纤维化和对肝脏纤维化分期.     

IEC 60601-1:2005(通标3.0)应用于欧盟医疗器械监管时48个常见问题和解答

IEC 60601-1:2005(通标3.0)自2005年发布以来,逐步被越来越多的国家和地区转换和采纳.欧盟于2012年6月1日结束了使用该标准的过渡期,取代了IEC60601-1:1988(通标2.0),正式用于医疗器械指令(MDD)中基本要求的符合性验证.本文介绍了欧盟在执行通标3.0中遇到的问题,以及欧盟专家组对这些问题的回答,计9个方面,48个问题.欧盟专家组的解答在欧盟具有较高的权威性.目前我国正在转化通标3.0,相信该文对制造商、第三方检测机构和政府监管机构有很多可借鉴之处.     

形成性评价体系在临床检验教学中的应用

临床检验教学是理论知识和实践相结合的教学,传统的总结性评价已不能达到公正有效的评价临床检验教学和改善教学体系的目的。因此,鉴于临床检验教学的特殊性,将形成性评价应用于临床检验教学中,充分调动学生学习的积极性,及时调整教学策略,以达到提高检验教学质量的目的。     

功能性踝关节不稳足底压力分析

目的 观察功能性踝关节不稳(FAI)患者的足底压力分布特征。     

Association study of the endothelial nitric oxide synthase gene polymorphisms with essential hypertension in northern Han Chinese

Background Nitric oxide （NO） synthesized by endothelial nitric oxide synthase （eNOS） plays an important role in both the regulation of endothelial function and the control of blood pressure. Up to now, there has been conflicting data regarding the association between three clinically relevant polymorphisms （T-786C, intron4b/a and G894T） of the eNOS gene and essential hypertension.     

荧光定量PCR技术在基因治疗药物组织分布研究中的应用

介绍应用荧光定量PCR技术对基因治疗药物组织分布研究的实验方法。从以下几个方面,即定量PCR技术原理、实验设计思路、各种检测方法的比较来说明这一问题。其中,可以使用的检测方法包括紫外定量法和引入内参基因法,后者又可以分为外标法和内标法。充分对比了这些方法的优缺点,并结合本实验室的研究现状,介绍了本监测中心在选用外标法进行研究时所取得的一些成果和实验经验。     

苦菊提取物对HepG2细胞的抗氧化作用及其机制研究

目的：考察苦菊提取物（CEE）对H₂O₂致HepG2细胞氧化应激损伤的保护作用,并探讨苦菊提取物在HepG2细胞中抗氧化作用机制。方法：通过MTT法和DCFH-DA荧光染色,检测H₂O₂处理HepG2细胞的活性和胞内ROS水平;在抗氧化反应元件（ARE）报告基因转染稳定的HepG2细胞内检测ARE-Luciferase活性;并通过荧光定量RT-PCR测定HepG2细胞内含有ARE序列相关基因的mRNA表达水平。结果：H₂O₂处理HepG2细胞后,细胞存活率下降,胞内ROS水平上升,而加入不同浓度的CEE则可明显改善上述结果。不同浓度的CEE处理转染ARE报告基因的HepG2细胞,可使细胞内的ARE活性呈浓度依赖性增强。此外,CEE可使HepG2细胞中含ARE序列的调控基因GCLC,GCLM和HMOX-1的mRNA表达水平上调,并呈浓度依赖性。结论：CEE通过降低ROS水平,抑制H₂O₂诱导的HepG2细胞损伤,而CEE对HepG2细胞的抗氧化保护作用机制可能与其激活HepG2细胞内Nrf2-ARE通路相关的抗氧化防御系统密切相关。     

Thrombophilias: An overview

Thrombophilias are defined as conditions that increase one’s risk of developing thromboembolic phenomena. Most patients with these conditions are asymptomatic, except when in the presence of a secondary trigger, namely a high-risk situation (both physiologic and otherwise). Over the past years, the importance of recognizing these conditions, and the effects of early intervention, have been emphasized. In particular, in the field of obstetrics and gynecology, thrombophilias play a major role. As will be described, there are several well-defined conditions in pregnancy that have been found to be associated with these conditions. Appropriate early intervention may have a significant impact on pregnancy outcome. It is the responsibility of the physician to be familiar with these syndromes, their detection, and appropriate management. The theory behind these syndromes, a brief review of the coagulation cascade, a review of the individual syndromes, and special circumstances will be described below in an attempt to assist the primary care physician in becoming familiar with these conditions.     

Characterization of MgNd2 alloy for potential applications in bioresorbable implantable devices

The aim of this study is to investigate and demonstrate the mechanical and corrosive characteristics of the neodymium-containing magnesium alloy MgNd2 (Nd2), which can be used as a resorbable implant material, especially in the field of stenting applications. To determine the mechanical characteristics of Nd2, tensile and compression tests were initially carried out in the hot extruded state. Here a unique elongation ratio (～30%) of the alloy could be observed. Subsequent T5 and T6 heat treatments were arranged to reveal their effect on the alloy's strengths and elongation values. The general degradation behaviour of Nd2 in a 0.9% NaCl solution was investigated by means of polarization curves and hydrogen evolution. In addition to this, by using various in vivo parameters, a corrosion environment was established to determine the alloy's degradation in vitro. Here, the mass loss per day in (MgF(2) and Bioglass)-coated and uncoated states and the corresponding maximum forces resulting from subsequent three-point bending tests revealed slow and steady corrosion behaviour. The cell viability and proliferation tests carried out on L-929 and MSC-P5 cells also showed good results. The mechanical and corrosive characteristics determined, as well as the in vitro test results obtained within the scope of this study, led to the development and successful in vivo testing of an MgF(2)-coated Nd2 mucosa stent which was introduced as an appropriate resorbable application.     

3.0T质子磁共振波谱在诊断胰腺癌中的初步应用

目的观察胰腺癌的质子磁共振波谱(1H-MRS)表现,分析其代谢物峰改变。方法 3.0 T磁共振系统下,应用单体素点分辨波谱(PRESS)序列,在自动匀场扫描使线宽小于25 Hz和抑水效果大于80%前提下,采集20例胰腺癌病人和20例健康志愿者胰腺的质子磁共振波谱。分析胰腺波谱中代谢物的表现,比较两组的代谢物峰显示率,以及每一组中胆固醇和不饱和脂肪酸的混合峰(Chol+Unsat)与脂肪峰(Lip)峰高的比(Chol+Unsat/Lip)。结果胰腺1H-MRS能够显示的主要代谢物峰有Lip峰,Chol+Unsat峰和胆碱峰(Cho)。虽然两组之间Cho峰的显示率差异无统计学意义(χ2=1.129,P=0.288)但胰腺癌组Chol+Unsat/Lip高于正常胰腺组,差异有统计学意义(t=2.751,P=0.010)。结论 3.0 T胰腺1H-MRS中Chol+Unsat/Lip增高,可能对诊断胰腺癌有一定参考价值。