基于核磁共振技术的生物阻抗成像研究进展

我们对最新发展的阻抗成像方法--核磁共振电阻抗成像(Magnetic resonance electrical impedance tomography,MREIT)技术进行了综述,简要介绍了CT(Computerized tomography,CT)和MRI(Magnetic resonance imaging,MRI)成像技术的基本原理,详述了MREIT技术基本理论和目前MREIT算法的发展状况,并就MREIT的发展前景及目前存在的问题进行了分析.     

以HPLC法测定马来酸氯苯那敏含量的方法中马来酸峰及氯苯那敏峰定位的问题

目的：探讨在《国家药品标准化学药品地方标准上升国家标准》收载品种中采用HPLC方法测定马来酸氯苯那敏的含量时，所采集的HPLC图谱中，出现的马来酸峰与氯苯那敏峰保留位置如何确定的问题。方法：采用高效液相色谱法，色谱柱：Waters C18（4．6mm×150mm，5μm），江苏淮阴C18（4．6mm×250mm，5μm）；流动相：庚烷磺酸钠溶液（冰醋酸调pH值至3．3）-甲醇-乙腈（25：30：18）；检测波长262nm。结果：在本文收集的试验条件下所采集的色谱图中，马来酸氯苯那敏对照品均出现了前后两个峰，马来酸峰与氯苯那敏峰保留位置可能在不同的色谱条件下有明显变化。结论：色谱图中马来酸峰与氯苯那敏峰保留位置应加以确定，以防止对马来酸氯苯那敏对照品纯度产生疑虑。     

BRI基因在一对转移能力不同的肺腺癌细胞系中的序列分析与表达研究

目的 确认淀粉样纤维蛋白基因(amyloid fibrils，BRI)基因在l对同源但转移能力不同的肺腺癌细胞系AGZY83-a和Anip973中的序列并分析其表达。方法 采用测序技术，Northern印迹杂交。G显带后荧光原位杂交分析BRI基因在肺腺癌细胞系的序列与表达。结果 BRI基因在高转移肺腺癌细胞系Anip973中高表达，在其低转移母系AGZY83-a中低表达，两细胞系BRI基因染色体定位区均存在断裂重排。该基因染色体定位区在Anip973中出现扩增。已知BRI基因的-116bp～-5bp处碱基序列和-115bp～-5bp处碱基序列在AGZY83-a和Anip973中分别突变为CTCAGCAGCCCGC和TCAGCCGC。结论 BRI基因在转移能力不同的肺腺癌细胞系差异表达与该基因的染色体定位区域的断裂重排无关，与该基因染色体定位区拷贝数增加及5′非翻译区存在不同的突变可能相关。     

Recurrent genetic alterations in 26 colorectal carcinomas and 21 adenomas from Chinese patients

Colorectal cancer (CRC) is one of the most common malignancies worldwide. The incidence of CRC in the Chinese population has increased dramatically during the last two decades; however, nonrandom chromosomal alterations in Chinese patients have not been described. In the present study, comparative genomic hybridization (CGH) was applied to detect recurrent chromosome alterations in 26 primary colorectal carcinomas and 21 colorectal adenomas from Chinese patients. In CRC, several recurrent chromosomal changes were found, including gains of 8q (14/26 cases, 54%), 20q (54%), 3q (50%), 13q (50%), 5p (46%), 7p (42%), 7q (42%), and 12p (38%) and losses of 18q (65%) and 17p (42%). From comparison with previous CGH studies, the frequent gains of 3q and 12p might be distinctive occurrences in Chinese patients. The distribution of frequently found chromosomal alterations in different locations was studied. The gain of 20q was more frequently found in colon cancer (P<0.01) and the gain of 12p was more frequently found in rectal cancer. Chromosomal alterations were found in 19/21 of adenomas; the most frequent chromosomal alteration was the loss of 18q (9/21 cases, 43%). These recurrent alterations provide several starting points for the isolation of candidate oncogenes and tumor suppressor genes.     

磁共振波谱评价大脑半球代谢物的偏侧优势

为了利用无创性的磁共振波谱成像技术研究大脑半球代谢物的非对称性,本研究对56例正常成年人行磁共振波谱成像,主要对双侧大脑半球的4个解剖区域:额叶、颞叶、枕叶及顶叶的代谢物天门冬氨酸(NAA)、肌酸(Cr)、胆碱(Cho)进行测量,并以Cr为内参照物比较NAA和Cho相对含量(NAA/Cr、Cho/Cr)的侧别差异。结果表明:双侧额叶之间的NAA/Cr存在显著性差异,而Cho/Cr无显著性差异;在双侧颞叶之间,这2种比值均存在显著性差异;双侧枕叶之间Cho/Cr存在显著性差异,而NAA/Cr无显著性差异;双侧顶叶之间的NAA/Cr存在显著性差异,而Cho/Cr无显著性差异。本研究结果提示双侧大脑半球的代谢物存在偏侧优势。     

Vancomycin-resistant enterococcal bacteremia: comparison of clinical features and outcome between Enterococcus faecium and Enterococcus faecalis.

BACKGROUND AND PURPOSE: Vancomycin-resistant enterococci (VRE) have emerged as important nosocomial pathogens. This study was conducted to clarify the clinical features and outcome of patients with vancomycin-resistant enterococcal bacteremia. METHODS: Patients with vancomycin-resistant enterococcal bacteremia treated at a medical center in northern Taiwan between November 1998 and July 2006 were reviewed. Clinical and bacteriological characteristics of Enterococcus faecium and Enterococcus faecalis were compared. RESULTS: Twelve patients (6 males and 6 females) were included for analyses. The mean age was 69.3 years (range, 40 to 86 years), and 8 cases (66.7%) were older than 65 years. All patients had underlying disease. Two patients received total hip replacement before development of VRE bacteremia. Twelve patients had prior exposure to broad-spectrum antimicrobial therapy. Ten patients had prior intensive care unit stay and prior mechanical ventilation before VRE bacteremia. All of the patients (n = 12) had an intravascular catheter in place. Bacteremia was caused by E. faecalis in 4 patients and by E. faecium in eight. The portals of entry included urinary tract (8.3%), skin, soft tissue and bone (41.7%) and unknown sources (50.0%). E. faecium showed a higher rate of resistance to ampicillin and teicoplanin than E. faecalis (87.5% vs 0.0%, p=0.01). The 60-day mortality rate was higher in patients with E. faecium bacteremia than E. faecalis bacteremia (62.5% vs 0.0%), although statistical significance was not obtained (p=0.08). CONCLUSIONS: VRE bacteremia may have an impact on the mortality and morbidity of hospitalized patients. Patients with bacteremia caused by vancomycin-resistant E. faecium had a grave prognosis, especially immunosuppressed patients. The prudent use of antibiotics and strict enforcement of infection control may prevent further emergence and spread of VRE.     

遗传算法在256阵元相控阵高强度聚焦超声治疗系统多焦点控制中的应用

阐述了遗传算法优化多点超声聚焦的方法以及球面相控阵声场计算方法。对实验室研发的256阵元相控阵聚焦超声治疗系统作了简介。利用此遗传算法和声场计算方法，对轴上和离轴单焦点以及轴对称六焦点和非轴对称四焦点进行了256阵元相控阵的声场仿真，并观察了实验室研发的256阵元相控阵聚焦超声治疗系统作用于有机玻璃和透明仿体的实验结果。用遗传算法和声场计算方法的仿真和系统实验结果表明，此方法可在实际聚焦手术中准确地控制3维单焦点和3维多焦点。     

CT三维重建在侧颅底的应用研究

目的 探讨CT三维重建在侧颅底的应用价值。方法 15例健康成人在Picker5000全身CT机上行连续轴位扫描，将扫描获得的原始数据输入Voxel Q图像后处理工作站，采用表面阴影法(surface shaded display，SSD)进行三维重建。结果 侧颅底CT三维重建能清楚显示正常侧颅底孔、裂和重要的骨性标志。重建的结构可整体显示或切割后单独显示，两均可在三维空间绕任意轴旋转任意角度。结论 三维CT能立体而直观的显示侧颅底骨性结构，有利于侧颅底外科手术方案的设计。     

重组人纽兰格林对正常恒河猴心脏的影响

探索重组人纽兰格林对健康成年恒河猴心脏的作用.将10只健康成年实验恒河猴随机分为实验组及对照组,分别注射等量重组人纽兰格林及生理盐水,采用超声心动图对用药前、用药即刻60 s内及用药10 d后相关指标进行测量,比较两组之间及不同时间之间各指标的差异.结果表明:重组人纽兰格林对健康实验恒河猴的舒张末期左室内径及容积、收缩末期左室容积、每搏量有影响,且随着用药时间的延长4者均增大,而重组人纽兰格林对健康恒河猴的左室射血分数及短轴缩短率没有显著影响.本研究认为重组人纽兰格林对健康成年恒河猴左心室容积有影响,而对心肌收缩力无显著影响.     

siRNA抑制外源绿色荧光蛋白在neuro-2a细胞株中的表达

目的：用RNAi技术抑制哺乳动物神经元中外源报告基因的表达，并探讨该过程中RNAi的时间及剂量效应，为利用RNAi技术研究神经元基因功能提供参考。方法：采用神经细胞来源的细胞系neuro-2a小鼠神经瘤细胞为模型，将外源绿色荧光蛋白（GFP）基因转染到neuro-2a细胞内，利用体外转录法合成siRNA，分为3个剂量组对其进行干扰。结果：Neuro-2a细胞可以被有效地转染，而且siRNA在neuro-2a细胞内可以有效发挥干扰作用。这种干扰作用呈现出一定的剂量效应。结论：RNAi技术可以成功用于neuro-2a细胞抑制基因的表达，这种对GFP表达规律及RNAi剂量效应的研究为利用RNAi技术研究神经元基因功能提供了一定的理论参考和依据。