TIA磁共振弥散加权成像异常的相关因素分析

目的探讨短暂性脑缺血发作(TIA)磁共振弥散加权成像(DWI)异常的相关因素。方法对2006年1月～2006年12月临床诊断为TIA的住院患者45例进行回顾性分析,比较DWI异常组和正常组的临床特征,并采用Logistic回归分析判定与DWI异常有关的独立因素。结果DWI异常14例(31%);多元回归分析提示TIA症状持续时间≥1h(OR=2.5,95%CI:1.3～8.6)和症状表现为失语伴运动障碍(OR=8.9,95%CI:2.1～36.5)与DWI异常独立相关。结论TIA患者DWI异常与TIA症状持续时间和症状表现为失语伴运动障碍有关。     

扩散张量成像和三维脑白质束示踪在多发性硬化中的临床应用

目的 探讨多发性硬化（MS）患者的MS斑块、斑块旁脑白质和T2WI上表现为正常的脑白质区（NAWM）的扩散张量成像（DTI）特点，并探讨DTI和三维脑白质束示踪技术对MS的应用价值。方法 对32例MS患者和32名与MS患者年龄性别配对的正常人进行头部DTI检查，生成表观扩散系数图（ADC）和部分各向异性图（FA），分别选取MS斑块、斑块旁脑白质区、NAWM区和对照组正常人相应脑白质区测量ADC值和FA值，并使用示踪技术做出三维脑白质束图像。结果 MS斑块、斑块旁脑白质区、NAWM区和对照组的ADC平均值分别为（1．233±0．119）、（0．973±0．098）、（0．748±0．089）×10^-3mm^2／s和（0．620±0．094）×10^-3mm^2／s，FA平均值分别为0．225±0．052、0．311±0．050、0．421±0．070和0．476±0．069。对MS斑块、斑块旁脑白质、NAWM数据进行随机区组方差分析最小显著差法检验，差异有统计学意义（P〈0．01）。MS斑块、斑块旁脑白质、NAWM分别和对照组配对t检验，差异有统计学意义（P〈0．01）。用三维脑白质束图像可以观察到MS斑块。结论 使用DTI检查生成的ADC图和FA图可以有助于评价MS中各部位脑白质的改变。通过三维脑白质束示踪图像可以立体直观地显示MS斑块区白质束的异常。     

The effect of central corneal thickness on estimates of the anterior chamber depth

Background: The slitlamp can be used to estimate the anterior chamber depth (ACD). The length of a slit object is increased until the corneal and iris/lens images appear to just touch. Multiplying the just‐touching‐slit‐length (JTSL) by a conversion factor gives an estimate of the ACD as measured by ultrasonography. The purpose of this study was to determine if central corneal thickness (CCT) affects the accuracy of this technique. Methods: The ACD of 50 subjects was measured by A‐scan ultrasonography and estimated by the slitlamp technique. CCT was measured by ultrasonic pachometry. The refractive error was determined subjectively. Results: The average ultrasonographic ACD for all subjects was 3.32 ± 0.65 mm. The average JTSL was 2.46 ± 0.38 mm. The conversion ratio between the ultrasonographic ACD and the average JTSL was 1.35. The predicted ACD using the regression equation of JTSL on the ultrasound anterior chamber depth (USACD) was 3.32 ± 0.54 mm. The corresponding value using the regression equation of JTSL and CCT on USACD was exactly the same, that is, 3.32 ± 0.54 mm. Conclusion: Incorporation of CCT into a regression equation does not improve the accuracy of the Smith technique.     

磁共振扩散加权成像对超急性期、急性期脑缺血的应用价值

磁共振扩散加权成像(DWI)可以快速、无创地反映脑缺血区分子水平发生的微观变化,为临床提供信息,本文对其在超急性期、急性期脑缺血的应用价值和限度进行综述。     

采用扩散张量纤维束成像技术研究活体Broca语言功能区及其纤维环路的结构

目的 采用扩散张量成像技术揭示健康人Broea区与其他脑功能区间的纤维联系规律。方法 健康成人20名，采用Siemens Trio 3．0T MR仪及工作站行数据采集和后处理及Broea区（B45和44区）纤维追踪，分析由语言功能区发出的神经纤维分布和走行。结果 BroeaB45区纤维束平均值左侧为428束，右侧相应脑区为416束，两侧差异无统计学意义（t=0．216，P〉0．05）；B44区纤维束平均值左侧为432束，右侧相应脑区为344束，两侧差异有统计学意义（t=2．314，P〈0．05）。B45区部分各向异性左侧平均为0．336，右侧同区为0．317（t=-3．656，P〈0．05）；B44区左侧平均为0．342，右侧同脑区为0．342（t=0．093，P〉0．05）。弓状纤维束平均左侧为199束，右侧为205束（t=-0．465，P〉0．05）；平均部分各向异性左侧为0．385，右侧为0．375（t=1．912，P〈0．05）。Broea区发出纤维走行和分布，主要向前上到额叶前部内侧面皮层下，过胼胝体到对侧相应结构，向外下穿外囊向后经颞叶到枕叶，向内下穿苍白球和内囊后肢向下行。结论 Broea区及其相关的纤维结构形成重要的语言纤维环路结构，结构完整是完成语言功能的基础。     

DTI在急性缺血性脑卒中所致皮质脊髓束损伤中的应用研究

目的:利用DTI探讨急性缺血性脑卒中病人大脑白质纤维束各向异性特征和皮质脊髓束受损与肌力的关系。方法:对9例正常被试和9例急性期缺血性脑卒中病人进行常规MR T1WI、T2WI和DTI检查,对数据进行离线后处理,采用dTV.II软件处理,获得FA图及方向编码彩色(DEC)图,并重建双侧皮质脊髓束3D纤维束图。结果:在正常组双侧白质纤维束FA值无明显差异,重建FA值图与方向编码彩色图可显示大部分主要的白质纤维束。在脑卒中病人组梗死区FA值显著低于健侧,两侧相比差异有显著性意义(t=4.570,P<0.001)。病变侧皮质脊髓束受压、变形、移位、部分断裂,皮质脊髓束受累情况与肌力有相关性(rs=0.888,P<0.05)。结论:DTI可显示脑内白质纤维束的走行及分布,为大脑白质纤维束的研究开辟了新的广阔领域。DTI FA值图及DEC图可以显示卒中病人梗死区白质纤维的方向与各向异性程度。3D纤维束图可以更立体直观的显示锥体束状况,有利于探讨皮质脊髓束损伤程度与肌力的关系,对临床及判断预后有重要价值。     

Assessment of the invasive potential of human gynecological tumor cell lines with the in vitro Boyden chamber assay: influences of the ability of cells to migrate through the filter membrane

The Boyden chamber assay is widely used for in vitro measurement of the invasive capacity of cells. However, results can be affected significantly if certain precautions are not taken. Using the Boyden chamber assay we investigated in vitro the invasive potential of a variety of human gynecological tumor cell lines to degrade and migrate through the artificial basement membrane matrix Matrigel. However, in the absence of this Matrigel layer large differences were observed in the ability of cells to adhere to, migrate through and attach to the lower side of the filter membranes. These differences were influenced by cell density, degree of directional locomotion, and the size of the filter pores. To adjust for these influences (which are not directly correlated to the capacity of cells to traverse the Matrigel layer), invasion results were corrected for the ability of cells to migrate through the filter membrane. In addition, the invasion of MDA-MB-231 cells was used as an internal standard to compensate for variations in the Matrigel layer between different experiments. Overall, in our experimental set up, the five human breast cancer cell lines were the most invasive (mean invasion ± SEM relative to MDA-MB-231 invasion: 104.7 ± 6.1%), the five human ovarian cancer cell lines the least invasive (60.2 ± 2.2%) and the six human endometrial cancer cell lines showed an intermediate capacity (79.1 ± 3.5%). In conclusion, the Boyden chamber assay can be used reliably for studying the invasive potential of cells in vitro, if the ability of the cells to migrate through the filter is taken into account, and a reference cell line is included to enable comparison of the data obtained from independently performed experiments on different cell lines.     

Estimation of instantaneous flow from the indicator-dilution curve after bolus injection of indicator

The indicator-dilution technique is commonly used to determine mean flow estimates. The estimation of instantaneous flow from the shape of an indicator-dilution curve is the objective of this study. Based on a mixing chamber approach to the flow system, a mathematical relationship is derived to reconstruct momentary flow from an indicator-dilution curve. This relationship is verified in a model setup both with only constant flow and with a sinusoidal flow variation superimposed. This method proved to give good flow estimates for limited values of flow parameters. Also, some preliminary experiments were performed in a pulsating flow system simulating heart action. The results were promising although the method proved to be very sensitive to baseline offset.     

后房型人工晶体植入术后早期并发症临床分析及处理

报告468例500眼后房型人工晶体植入术后2周内出现的并发症发生率,其中角膜水肿73.6％,色素膜炎症反应88.4％,瞳孔变形12.8％,人工晶体表面渗出膜3.8％,后囊混浊13.8％,短暂性高眼压5.2％,晶体皮质残留5.8％,人工晶体偏位2.6％,前房出血3％。提高术后视力的关键是提高手术技巧以减少并发症的发生。     

Physicochemical aspects of drug release. XV. Investigation of diffusional transport in dissolution of suspended, sparingly soluble drugs

The dissolution rates of sparingly soluble, fine particulate, suspended drugs have been studied using a Coulter Counter Model TAII. For two sieve fractions of oxazepam the dissolution rates were monitored in media with varying viscosities brought about by the addition of glycerol, while for griseofulvin the change in the medium's viscosity was induced by changing the temperature. By calculating the dissolution rate, and compensating for differences in particle surface area and media solubility, it was shown that the dissolution rate was diffusion controlled. After additional normalization for the diffusion coefficient, it was suggested that the so-called apparent diffusional distance decreased substantially with particle size. The effect of particle size was more limited above approx. 15 μm.