小鼠胚胎干细胞植入大鼠脑内分化的研究

观察小鼠胚胎干细胞植入大鼠隔区和海马内之后的分化状况。以 SD大鼠为宿主 ,将胚胎干细胞移植入宿主隔区和海马内 ,移植后在 l、2、3、4和 8周取脑 ,冰冻切片 ,进行 Nissl染色和 M6、NSE、GFAP免疫组织化学反应。胚胎干细胞移植入大鼠隔区和海马之后 ,从第 2周开始表达 M6、GFAP、NSE等抗原 ,持续至第 4周 ,主要位于移植区内 ,较少迁移。小鼠胚胎干细胞移植入大鼠隔区和海马内之后 ,分化为神经元和神经胶质细胞     

Peripheral nerve regeneration by microbraided poly(L-lactide-co-glycolide) biodegradable polymer fibers

Tiny tubes with fiber architecture were developed by a novel method of fabrication upon introducing some modification to the microbraiding technique, to function as nerve guide conduit and the feasibility of in vivo nerve regeneration was investigated through several of these conduits. Poly(L-lactide-co-glycolide) (10:90) polymer fibers being biocompatible and biodegradable were used for the fabrication of the conduits. The microbraided nerve guide conduits (MNGCs) were characterized using scanning electron microscopy to study the surface morphology and fiber arrangement. Degradation tests were performed and the micrographs of the conduit showed that the degradation of the conduit is by fiber breakage indicating bulk hydrolysis of the polymer. Biological performances of the conduits were examined in the rat sciatic nerve model with a 12-mm gap. After implantation of the MNGC to the right sciatic nerve of the rat, there was no inflammatory response. One week after implantation, a thin tissue capsule was formed on the outer surface of the conduit, indicating good biological response of the conduit. Fibrin matrix cable formation was seen inside the MNGC after 1 week implantation. One month after implantation, 9 of 10 rats showed successful nerve regeneration. None of the implanted tubes showed tube breakage. The MNGCs were flexible, permeable, and showed no swelling apart from its other advantages. Thus, these new poly(L-lactide-co-glycolide) microbraided conduits can be effective aids for nerve regeneration and repair and may lead to clinical applications.     

Nucleolar localization of non-structural protein 3b, a protein specifically encoded by the severe acute respiratory syndrome coronavirus

The open reading frame 3 (ORF3) of the severe acute respiratory syndrome coronavirus (SARS-CoV) genome encodes a predicted 154-amino acid protein, which lacks similarities to any known protein, and is named 3b. In this study, it was shown that 3b protein was predominately localized to nucleus with EGFP tag at its N- or C-terminus. The localization patterns were similar in different transfected cells. Immuno-fluorescence assay revealed that 3b protein was co-localized well with C23 in nucleolus. C23, B23 and fibrillarin all are important nucleolar proteins, which localize in the region of the nucleolus. Co-transfection of p3b-EGFP with pC23-DsRed, pB23-DsRed and pfibrillarin-DsRed further confirmed 3b's nucleolus localization. With construction of serial truncated mutants of 3b, a region (residues 134-154 aa) responsible for nucleolar localization was determinated in 3b protein. These results provide a new insight for further functional studies of SARS-CoV 3b protein.     

恒河猴骨髓间充质干细胞分离培养及其生长特性

采用密度梯度离心和贴壁筛选方法分离纯化了恒河猴骨髓间充质干细胞(mesenchymal stem cells from bone marrow of Rhesus monkey,RhBMSCs);通过表面抗原检测和核型分析对细胞进行了初步鉴定;通过生长曲线的绘制和细胞凋亡的检测探讨了细胞的生长特点。本实验获得的RhBMSCs形态以梭型为主,核型正常,CD29表达率为99.2%,CD34、CD45、HLA-DR表达率均低于3.2%,RhBMSCs表型符合间充质干细胞的特点,且纯度较高,细胞生长旺盛,但倍增时间有随传代数的增加而逐渐延长的趋势。本实验探讨了RhBMSCs的体外分离、扩增培养及鉴定的方法,并对其生长特点进行了初步观察,这不仅有助于进一步了解与之近似的人的骨髓间充质干细胞的相关特性,而且为以猕猴为对象的BMSC定向分化和组织修复等动物体内实验打下了基础。     

A Strain Device Imposing Dynamic and Uniform Equi-Biaxial Strain to Cultured Cells

The objective of this study is to design a new apparatus to allow the control of the magnitude and frequency of dynamic stretch applied uniformly to cells cultured on a silicon elastic membrane. The apparatus is designed to produce equi-biaxial dynamic stretches with area changes ranging from 0% to 55% and frequencies ranging from 0 to 2 Hz. Homogeneous finite strain analysis using triangles of markers was performed to compute the symmetric two-dimensional Lagrangian strain tensor on the membrane. Measurements of strain in both static and dynamic conditions showed that the shear component of the strain tensor (E_rc) was near zero, and that there was no significant difference between radial (E_rr) and circumferential (E_cc) components, indicating the attainment of equi-biaxial strain. Bovine aortic endothelial cells were transiently transfected with a chimeric construct in which the luciferase reporter is driven by TPA-responsive elements (TRE). The transfected cells cultured on the membrane were stretched. The luciferase activity increased significantly only when the cells were stretched by 15% or more in area. Cells in different locations of the membrane showed similar induction of luciferase activities, confirming that strain is uniform and equi-biaxial across the membrane. © 1998 Biomedical Engineering Society. PAC98: 8780+s, 8745-k, 8722-q     

内皮型、诱导型一氧化氮合酶在乳腺癌中的表达

目的 :研究内皮型一氧化氮合酶 (eNOS)、诱导型一氧化氮合酶 (iNOS)在乳癌中表达及与淋巴结转移的关系。方法 :采用免疫组化S P法检测 60例乳癌中eNOS和iNOS的表达。结果 :eNOS和iNOS阳性在乳癌中表达率分别为 75 0 %和71 7%。在淋巴结转移组和无淋巴结转移组中eNOS阳性表达率分别为 66 7%和 83 3 % ,两组间差异无统计学意义 (χ2 =2 2 2 ,P >0 0 5) ,而iNOS在淋巴结转移和无转移组中阳性表达率分别为 53 3 %和 90 0 % ,两组间差异有统计学意义 (χ2 =9 93 ,P <0 0 1 )。结论 :内皮型、诱导型一氧化氮合酶在乳腺癌中高表达 ;iNOS的表达与乳腺癌的淋巴转移相关     

大鼠咽肌前运动神经元的跨突触定位

支配咽肌的运动神经元位于疑核，控制凝核的前运动神经元位于孤束核。孤束核中的前运动神经元在控制吞咽运动中起着重要作用。但支配咽肌的前运动神经元位于孤束核的什么部位还不清楚。文内用假狂犬病毒研究字大鼠咽肌前运动神经元在孤束核中的定位。     

肿瘤抑制基因变异的分子病理学研究进展

肿瘤分子生物学研究已经证实,肿瘤是一种基因病,是由多基因变异并长期累积所致,其中肿瘤抑制基因（TSG）在肿瘤发生过程中持续丧失功能被认为是导致细胞恶变的最重要事件之一。TSG变异的最常见分子机制是因其2个位点相继因点突变和杂合性缺失（LOH）而导致功能完全失活,即广为接受的Knudsen“二次打击”理论。另一个受到高度重视的基因变异类型是DNA错配修复基因（mismatch repair,MMR)功能的失活,其分子特征是基因组DNA微卫星小体不稳定性（microsatellite instability,MSI)。这两种基因变异形式最终都将导致细胞分裂和增殖活动脱离还调控而发生肿瘤。由于LOH和MSI是肿瘤细胞的重要标志性特征,并具有分子病理学上的诊断意义而受到广泛关注。     

抗蓖麻毒素A链人源化单域抗体的设计、原核表达及生物活性检测

目的 运用计算机辅助蛋白质分子设计的方法设计针对蓖麻毒素A链(RTA)的拮抗肽,实现在大肠杆菌B121中的可溶性表达,并对其生物学活性进行评价.方法 根据RTA的晶体结构、RTA-rRNA相互作用复合物模型,在CVFF(consistent-valence force field)、Amber力场下,对RTA的空间构象进行理论模拟,初步确定其生物活性功能域;然后针对该功能域设计小分子拮抗肽,并借助人抗体重链町变区骨架,在CDR3区对拮抗肽进行展示,用重叠延伸PCR全基因合成人源化的单域抗体并克隆至载体pET-32a(+);双酶切和DNA测序技术对构建的载体进行鉴定;IPrG诱导人源化的单域抗体表达,用镍离子亲和层析纯化,竞争ELISA和MTT法分别进行结合和中和活性检测.结果 从头搭建并设计合成了人源化的单域抗体,实现了其原核表达,并进行了牛物活性检测;建立了基于人源化的单域抗体的RTA和蓖麻毒素检测方法.结论 研究结果为新型蓖麻毒素小分子拮抗剂的研制奠定了理论和实验基础.