Live/Real Time Three‐Dimensional Transthoracic Echocardiographic Assessment of Inferior Vena Cava and Hepatic Vein Thrombosis in Sickle Cell Disease

We describe the value of live/real time three‐dimensional transthoracic echocardiography (3DTTE) over two‐dimensional transthoracic echocardiography (2DTTE) in the assessment of inferior vena cava (IVC) and hepatic vein (HV) obstruction in a patient with sickle cell disease. 3DTTE provided additional information when compared to 2DTTE by (1) identifying the obstructing lesion as a likely thrombus, (2) by providing assessment of anatomical severity of IVC lumen obstruction since the thrombus could be visualized en face also, and (3) identifying an area of increased mobility of a portion of the thrombus suggesting greater risk of embolization. (Echocardiography 2010;27:594‐596)     

人CDK2-AP1(DOC-1)酵母双杂交诱饵质粒自激活作用鉴定

目的验证诱饵质粒pBD—DOC-1在酵母双杂交系统的自激活性及毒性作用，为应用酵母双杂交系统（yeasttwo—hybrid system）筛选与p12DOC-1／CDK2-AP1相互作用的蛋白建立实验基础。方法将诱饵质粒pBD—DOC-1转化到酵母细胞MAV203中，检测诱饵蛋白有无毒性和自激活作用。同时利用对照质粒组筛选组氨酸（His）本底表达抑制剂3AT（3-氨基．1，2，4-三唑）的合适工作浓度。结果诱饵质粒pBD．DOC—1成功转化到酵母细胞MAV203中，对宿主酵母细胞无毒性，对报告基因无自激活作用。确定了组氨酸（His）本底表达抑制剂3AT（3-氨基-1，2，4-三唑）的合适工作浓度。结论诱饵质粒pBD—DOC-1可以用于酵母双杂交实验，为进-步运用酵母双杂交技术在人类组织cDNA文库中筛选与之相互作用的蛋白奠定了基础。     

Latent class models for medical diagnostic tests in multicenter trials

Medical diagnostic tests must enjoy appropriate validity and high reliability in order to qualify as adequate assessment tools. Without a gold standard test, available medical diagnostic tests are not perfect; hence, the reliability of such tests must be evaluated precisely. Kappa coefficient statistics are often utilized to assess reliability of tests when there are two or more medical diagnostic tests. However, the statistics are imprecise for a typical case when the prevalence rate of a target disease is unknown. Although latent class models could be used to assess reliability, the models cannot estimate reliability in the case of two tests, due to unidentifiability or the lack of degrees of freedom. An alternative approach to assess reliability for the case of two tests is stratifying a two‐by‐two contingency table under the assumption that sensitivities and specificities between the two tests be equal over all strata and that prevalence rates in the strata be different from each other. Because stratification is basically a multi‐sample analysis, it should not be applied to the situation where subsamples (i.e., centers) are randomly selected from a larger population. In this article, a type of mixed‐effect model is proposed to evaluate the reliability of two tests for trials in randomly selected multiple centers. Several types of distributions for prevalence rates over subpopulations are considered. Simulation studies show that our proposed method performs nicely. Analysis of real data is also reported. Copyright © 2013 John Wiley & Sons, Ltd.     

Live/Real Time Three‐Dimensional Transthoracic Echocardiography in the Evaluation of Post Traumatic Acquired Thoracic Aortic Coarctation

We report a young patient with post traumatic acquired thoracic aortic coarctation in whom three‐dimensional transthoracic echocardiography (3DTTE) demonstrated incremental value over two‐dimensional transthoracic echocardiography (2DTTE). 3DTTE showed (1) en face views of the obstruction site that showed a markedly narrowed, roughly circular orifice measuring 0.33 cm² in area, (2) echogenic tissue encroaching on the graft lumen consistent with fibrosis/thrombus, and (3) no graft protrusion into the aortic lumen, only hypermobility of the medial portion of the graft. These important findings were not detected by 2DTTE. (Echocardiography 2010;27:470‐472)     

Plasma membrane insertion of TRPC5 channels contributes to the cholinergic plateau potential in hippocampal CA1 pyramidal neurons

In cultured hippocampal neurons, transient receptor potential 5 (TRPC5) channels are translocated and inserted into plasma membranes of hippocampal neurons to generate nonselective cation (NSC) currents. We investigated whether TRPC5 channel translocation also contributes to the generation of NSC currents underlying the afterdepolarizations and plateau potentials (PPs) in hippocampal pyramidal cells that are induced by muscarinic receptor activation. Using a biotinylation assay to quantify the change in surface membrane proteins in acute hippocampal slices, we found that muscarinic stimulation significantly enhanced the levels of TRPC5 protein on the membrane surface but not those of TRPC1 or TRPC4 channels. We then investigated the pharmacological sensitivity of the cation current observed during muscarinic stimulation to determine if a component could be due to TRPC5 channels. The TRPC channel antagonists 2‐APB and SKF96365 strongly depressed the generation of PPs, the underlying tail currents (I_tail) and the associated dendritic Ca²⁺ influx induced by muscarinic receptor activation in pyramidal neurons. High intracellular concentrations of ATP, which specifically inhibit TRPC5 channels, depressed I_tail. In addition, pretreatment with the calmodulin (CaM) inhibitor W‐7, which depresses recombinant TRPC5 currents, inhibited both the cation current (I_tail) and the surface insertion of TRPC5 channels. Finally, the phosphatidylinositide 3‐kinase (PI₃K) inhibitor wortmannin, which blocks translocation of TRPC5 channels in cell culture, also inhibited both the I_tail and the surface insertion of TRPC5 channels. Therefore, we conclude that insertion of TRPC5 channels contributes to the generation of the prolonged afterdepolarizations following muscarinic stimulation. This altered plasma membrane expression of TRPC5 channels in pyramidal neurons may play an important role in the generation of prolonged neuronal depolarization and bursting during the epileptiform seizure discharges of epilepsy. © 2010 Wiley‐Liss, Inc.     

胰岛素受体底物和酪氨酸磷酸酶在 2 型糖尿病大鼠肌肉组织中的蛋白表达及其意义

目的研究2型糖尿病对胰岛素产生抵抗的分子机制。方法用Western杂交检测2型糖尿病模型(OLETF大鼠)肌肉组织内IRS-1及SH-PTP2的蛋白表达水平,并以同种属的Wistar大鼠做比较。结果OLETF糖尿病大鼠的空腹和餐后血糖水平较对照组明显增高(P<0.05);Western杂交显示OLETF大鼠肌肉组织内IRS-1蛋白表达较对照组减少(P<0.05);而SH-PTP2的蛋白表达则较对照组增加(P<0.05)。结论IRS-1及SH-PTP2蛋白表达的异常改变,可能是引起2型糖尿病产生胰岛素抵抗的分子机制之一。     

二次分冠"抽屉"式拔除水平阻生齿临床效果评价

目的观察采用二次分冠“抽屉”式拔除法拔除阻生齿的临床效果。方法观察实验组60只阻生齿用二次分冠法拔除效果,与对照组60只阻生齿常规翻瓣法拔除比较。结果二次分冠法拔除阻生齿成功率为95%。实验组手术时间明显比对照组手术时间短(P<0.05)。两组患者局部肿胀、疼痛和张口受限程度存在显著性差异(P<0.05)。结论采用二次分冠法拔除阻生齿,手术简便,时间短,术后不良反应少。     

桂枝汤类方的双向调节作用

桂枝汤及其类方对于体温、汗液、心律、血压、大肠功能等具有双向调节作用。这种作用的产生有其特定的前提,基础和途径。其实质可能是通过调营卫、建中气,来调动机体内因对抗疾病,从而使内环境始终保持动态平衡,来实现其双向调节作用。     

应用酵母双杂交技术研究人睾丸特异表达基因HSD-3.8的功能

目的探寻本实验室筛选出的与不孕症相关的人睾丸特异表达基因HSD-3.8(GenBank接收号为AF311312,国际上命名为精子相关抗原1)编码蛋白质的作用配体,揭示其参与受精过程的机制。方法采用酵母双杂交体系,构建含有HSD-3.8基因部分序列(HSD-0.7)的诱饵质粒,筛选人卵巢cDNA文库。在获得阳性克隆后,根据蛋白质结构分析并结合PCR方法重新构建一系列缺失体,在酵母体内验证它们与被捕获的蛋白因子之间的结合。结果酵母双杂交实验获得一阳性克隆,其编码氨基酸与人G蛋白β1亚基羧基端的144个氨基酸同源性为100%。所构建的几种诱饵蛋白缺失体在酵母体内均不能与该捕获的蛋白因子相互作用。结论HSD-3.8编码蛋白质片段HSD-0.7可能通过G蛋白信号转导途径在受精过程中发挥功能,与G蛋白β1亚基的结合有赖于其结构的完整。     

Minimax two-stage-designs with applications to tissue banking case-control studies

'Tissue banks' are created, at least in part, to help medical scientists learn about disease biology on the basis of samples provided by patients on treatment protocols that were competed years earlier.The bank inventory consists of precious non-renewable patient material (such as frozen diagnostic blood or bone marrow), which can be linked to both clinical data and long term follow-up information. Case-control studies, where cases represent clinical failures and controls clinical successes, are ideal for rapidly learning if a laboratory marker might have prognostic significance. While group sequential (multi-stage) methods are widely used in clinical trials, they have rarely been applied in case-control studies. Further, unlike clinical trials where safety and efficiency may actually be in conflict, case-control studies can focus on efficiency. Hence, minimizing the expected sample size is a desirable goal in such a setting. Since the true effect size is never known, and since no prior distribution can be postulated for the effect size, we have opted for the minimax solution. A strategy is developed to determine amongst all two-stage designs with given type I and type II errors, the one for which the maximum expected sample size is minimized. The user is provided with simple tables, whereby one can determine everything necessary to conduct the study from the corresponding calculation for a single-stage design. A matched pair example is given where the suggested design can be modified, to obtain a superior 'two-plus' stage design. The basic idea is to conduct the first stage as planned, but use the estimate of variance to redesign the study, without using the estimate of effect size in the redesign.