一种抑制反向感应电场的磁刺激线圈设计方法探讨

在无创性脑神经磁刺激技术中,多采用8字形磁刺激线圈,在线圈周围一定距离的空间中,对应8字线圈中心出现感应电场最大值,对应两个边缘处出现反向感应电场峰值,后者容易在刺激目标处产生副刺激,分析了8字形磁刺激线圈感应电场的分布,针对其反应方向感应电场幅值较大,容易引起副刺激的问题提出了新的磁刺激线圈设计方法,以抑制感应电场副峰,并进行了计算机模拟和验证。     

微小隐孢子虫CP23基因真核表达载体的构建及表达

为了构建微小隐孢子虫子孢子表面蛋白CP2 3基因真核表达载体pCR3 1 2 3,观察其在Hela细胞中的表达。本研究用EcoRⅠ从pMD18 T 2 3中酶切得到CP2 3基因片段 ,将其插入真核表达载体pCR3 1(+)的EcoRⅠ位点 ,构建CP2 3基因真核表达载体pCR3 1 2 3,脂质体介导法将其转染Hela细胞 ,并用G4 18加压筛选 ,用RT PCR方法检测外源CP2 3基因的转录、ELISA法和间接免疫荧光法检测其活性。酶切鉴定表明已成功构建了重组真核表达载体pCR3 1 2 3;外源CP2 3基因能在转染细胞中有效转录 ;ELISA法和间接免疫荧光法实验结果表明表达产物具有良好的生物活性     

分化抗原5C5在人免疫细胞的表达

目的　明确 5C5蛋白为分化抗原 ,检测其在人免疫细胞的表达 ,以及它的信号传导作用。方法　用 5C5蛋白免疫小鼠 ,制备抗 5C5蛋白的单抗。用反义技术制备 5C5蛋白表达抑制的 3D5细胞。用免疫荧光染色和Western印迹确定 5C5单抗的特异性。用胞膜蛋白免疫沉淀和流式细胞术确定其分化抗原的性质。用双色免疫荧光染色流式细胞术检测 5C5分化抗原在多种人免疫细胞的表达。用Fura 3 AM试剂作探针 ,用激光共聚焦显微镜观察胞内Ca2 + 浓度的变化。结果　制备了抗 5C5蛋白的特异性单抗。用 5C5单抗作探针 ,从 3D5细胞膜免疫沉淀到 1条相对分子质量 (Mr)为 19× 10 3的蛋白带 ,并在活 3D5细胞见阳性免疫荧光染色。 5C5分化抗原在人周围血CD19+ 、CD14 + 、CD4 + 、CD8+ 和CD5 6 + 细胞的表达率分别为 (33.4 7± 7.9) %、(86 .13± 6 .7) %、(15 .79± 7.1) %、(18.11±12 .77) %和 (11.76± 7.4 7) % ,在人免疫细胞株的表达率分别为 5 8.0 % (Nalm6 )、72 .7% (3D5 )、5 3.6 %(BJAB)、6 1.0 % (Daudi)、6 .9% (SKW6 )、6 .3% (Jurkat)、5 .8% (Peer)、2 1.3% (K5 6 2 )和 39.1% (U937)。3D5细胞在 5C5单抗刺激下 ,胞内Ca2 + 浓度逐渐增高 ,可达 2倍左右 ,对照小鼠Ig则无此作用。结论5C5蛋白为一个分化抗原 ,在人周     

分化抗原gp42在人免疫细胞的表达

目的　明确gp4 2蛋白为分化抗原 ,检测它在人免疫细胞的表达。方法　用gp4 2蛋白免疫小鼠 ,制备抗gp4 2蛋白的单抗。用反义技术制备gp4 2蛋白表达抑制的 3D5细胞。用免疫荧光染色和Western印迹确定gp4 2单抗的特异性。用胞膜蛋白免疫沉淀和流式细胞术确定gp4 2蛋白为分化抗原。用双色免疫荧光染色流式细胞术检测gp4 2分化抗原在多种人免疫细胞的表达。结果　制备了抗gp4 2蛋白的特异性单抗。用gp4 2单抗作探针 ,从 3D5细胞膜免疫沉淀到相对分子质量 (Mr)为4 2 0 0 0的一条蛋白带 ,并在活 3D5细胞见阳性免疫荧光染色。gp4 2分化抗原在人外周围血CD19+ 、CD14 + 、CD4 + 、CD8+ 和CD5 6 + 细胞的表达率分别为 5 9.71%± 11.36 %、89.0 8%± 4 .87%、2 6 .0 3%±9.75 %、2 4 .2 4 %± 15 .2 9%和 2 4 .2 0 %± 15 .72 % ,在人免疫细胞株的表达率分别为 5 8.0 % (Nalm6 )、72 .7% (3D5 )、5 3.6 % (BJAB)、6 1.0 % (Daudi)、6 .9% (SKW6 )、6 .3% (Jurkat)、5 .8% (Peer)、2 1.3% (K5 6 2 )和 39.1% (U937)。结论　gp4 2蛋白为一个分化抗原 ,在人外周围血CD14 + 细胞的表达率最高 ,其次为CD19+ 细胞 ,CD4 + 、CD8+ 和CD5 6 + 细胞的表达率较低。     

CT快速图像重建算法研究

快速图像重建算法一直是图像重建中的关键问题和衡量CT系统的重要指标之一。本文以扇形束结构为例，分析了各种快速重建算法的特点，并从算法结构、实现技巧及代码优化等方面论述了快速图像重建的方法．这些方法可有效地提高图像重建的速度。     

bBMP异位诱导成骨的组织学长期观察

目的长期观察并获得单纯牛骨形态发生蛋白(bovine bone morphogenetic protein,bBMP)异位诱导成骨的组织学变化。方法(20±2)g昆明小鼠21只,麻醉后于双侧股部肌肉中直接植入块状bBMP各2mg,分别于第1、2、4、6、8、10、12周各处死3只,切取诱导分化组织,5%戊二醛固定,标本用10%EDTA脱钙后制作5μm石蜡切片,分别行甲苯胺蓝染色,HE染色,丽春红三色染色观察组织学变化情况。结果植入1周,大量分化良好的间充质细胞和幼稚软骨细胞形成一椭圆形分化组织块;植入2周,大量骨小梁生成,部分骨小梁边缘骨化;植入4周,骨小梁转化为成熟的骨质,骨质中有散在于骨细胞中的破骨细胞生成;植入6~12周,椭圆形骨组织块内部小梁骨逐渐吸收、断裂、不连接,但外周骨质逐渐塑形,局部成熟骨质周边仍伴有新生骨形成。结论bBMP无需任何载体即可在肌肉中异位成骨,具有强大的异位骨诱导能力;血供在异位骨的形成和维持中可能起着重要作用。     

藏羚羊和藏系绵羊左心室收缩功能的比较研究

目的:探讨藏羚羊适应高原低氧环境的左心功能特点。方法:捕捉海拔4 300 m藏羚羊9只、藏系绵羊10只运至格尔木(海拔2 800 m)实验基地。测定二者的心脏/体重比(HW/BW)、右心室/(左心室+室间隔)重量比[RV/(LV+IVS)];应用心导管技术测定心率(HR)、收缩压(SBP)、舒张压(DBP)、左室等容收缩期心室内压力上升最大速率和左室等容舒张期心室内压力下降最大速率(±dp/dt)。以格尔木市的氧浓度(21.1%)为基线,分别给予更低浓度氧14.6%、12.5%(分别相当于海拔5 300 m、6 300 m)的低氧吸入15 min后重复测定以上指标。应用透射电镜观察心肌超微结构。结果:藏羚羊HW/BW显著高于藏系绵羊(P0.01),基础状态下藏羚羊SBP低于藏系绵羊(P0.05),+dp/dt与藏系绵羊比无显著差异,吸入14.6%和12.5%的低氧气体后藏羚羊+dp/dt分别升高至145.1%和148.1%,而藏系绵羊分别降低至68.4%和70.5%(P0.05);电镜下观察藏羚羊心肌超微结构与藏系绵羊比较,其心肌细胞线粒体较为丰富。结论:藏羚羊心脏对高海拔低氧环境的适应,是通过增加心脏器官的重量及心肌细胞线粒体的含量来实现,其心肌收缩功能的适应性特征为:在静息状态下以较低的左心室心肌收缩力来降低氧耗量以此适应高原低氧环境,而以海拔更高的较低氧浓度为应激条件下,左心室心肌收缩力明显升高。提示:藏羚羊作为高原适应性动物,经过漫长的自然选择其心脏对高原低氧环境的适应不同于藏系绵羊。     

Applying target region amplification polymorphism markers for analyzing genetic diversity of Lentinula edodes in China

The target region amplification polymorphism (TRAP) technique was utilized for assessing the genetic diversity of 55 wild strains and one cultivated strain of Lentinula edodes in China. From these strains, 932 DNA fragments were amplified using 12 primer combinations, 929 fragments (99.68%) of which were polymorphic between two or more strains. The average coefficient of pairwise genetic similarity was 0.696, within a range from 0.503 to 0.947. Cluster analysis and principal coordinate analysis separated the tested strains of L. edodes into two major groups. Group A was further divided into seven subgroups. In most cases, the strains from the same or adjoining regions could be preferentially clustered into small groups. The results from the average genetic similarity and the weighted average value of Shannon's Information Index among the tested strains of L. edodes from the same region revealed a vast genetic diversity in the natural germplasm found in China. Compared with the L. edodes strains from other regions, those found on the Yunnan Plateau, in the Hengduanshan Mountains, in Taiwan, South China, and Northeast China showed greater genetic diversity. The results of the present study indicated that the wild strains of L. edodes in China possessed abundant genetic variation, and the genetic relationships among them were highly associated with the geographic distribution. This is the first report demonstrating that TRAP markers were powerful for analyzing the genetic diversity of L. edodes, and the study lays the foundation for a further application of this remarkable technique to other fungi. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

A mini pig model for visualization of perforator flap by using angiography and MIMICS

Background

Research performed using animal models has assisted in the understanding of flap anatomy and physiology. Pigs’ vasculature in the skin is anatomically and physiologically similar to human, making it an ideal model for research. Until now, most vascular imaging studies are of two-dimensions. The aim of this study is to provide a three-dimensional (3D) model that reveals detailed architecture of the vascular network of the porcine, for accurate quantitative assessment.

Methods

Five Guangxi Bama minipigs were anaesthetized intramuscularly and underwent whole body lead oxide–gelatin injection. Spiral computed tomography scanning was performed on the subjects and three-dimensional reconstructions were made. Another minipig was used, and underwent Cardiografin injection. 3D-reconstruction was executed in vivo. All subjects were then dissected by layers to document the individual perforators.

Results

Angiography using perfusion with lead oxide–gelatine mixture has the advantage of illustrating distinctively the vessels and their perforating branches. However, it is incapable of displaying other tissues structures. Angiography through perfusion with Cardiografin in vivo has the advantage of demonstrating the relationship between arteries and bones. Yet it could only display coarsely the vascular trunk, and is incapable of displaying the vascular network. By combining these two methods, the 3D structure, source, course, and territories of the arteries were presented distinctively.

Conclusions

3D modeling in combination with traditional sectional imaging of the pig model enables blood vessels to be displayed more dynamically with greater realism. The procedure described could be useful for future flap research, by offering a better visualization of the vascular structure of the skin flap, allowing for better anatomical understanding.