人脐静脉内皮细胞清除补体攻膜复合物的机制

目的：探讨内皮细胞清除补体攻膜复合物（MAC）的途径及其清除动力学，方法：原代培养的人脐静脉内皮细胞以RH414荧光标记质膜双层，0℃组装亚溶剂量的MAC，37℃复苏后，LSCM实时监MAC沉积诱导的质膜囊泡化形成和胞吞，胞吐情况,流式细胞仪定量检测内皮细胞表面MAC抗原的清除情况，结果：MAC沉积后，内皮细胞有的质膜囊泡化形成，囊泡以胞吞和胞吐2种方式离开细胞，并以前者占优，37度条件下，内皮细胞清除表面MAC的半衰期约为5min。结论：内皮细胞可通过胞吞和胞吐2种机制清除细胞表面沉积的MAC，并以胞吞方式为主。     

Inhibitory effect of ketamine on phosphorylation of the extracellular signal-regulated kinase1/2 following brain ischemia and reperfusion in rats with hyperglycemia

To determine if the inhibitory effects of ketamine on the extracellular signal-regulated kinase (ERK) 1/2 are involved in reduction of the hyperglycemia-exaggerated cerebral ischemic lesion, rats with normoglycemia, hyperglycemia, or hyperglycemia supplemented with ketamine were subjected to 15 min of forebrain ischemia, and then, reperfusion for 0.5, 1, and 3h. Phosphorylation of ERK1/2 in the brain tissues was assessed by immunohistochemistry and Western blot analysis. In rats with normoglycemia, we demonstrated a moderate increase of the ERK1/2 phosphorylation in the cingulum cortex and hippocampus CA3 following an ischemic intervention. It quickly dropped to control levels after reperfusion for 0.5h. In rats with hyperglycemia, however, the increase of the ERK1/2 phosphorylation in these areas was significantly higher in all animals reperfused. The neuronal death, detected by the TdT-mediated-dUTP nick end labeling assays, was found in the cingulum cortex (5.23+/-2.34, per high power feild) and hippocampus CA3 areas (6.29+/-3.68, per 1mm(2)) in hyperglycemic group after reperfusion for 3h. With ketamine treatment, the ERK1/2 phosphorylation in cingulum cortex and hippocampus CA1 and CA3 areas was found to be the same as that in normoglycemia rats. Our results suggest that hyperglycemia may increase the ischemic insult through modulation of the signal transduction pathways involving ERK1/2. The inhibitory effects of ketamine on the hyperglycemia-activated ERK1/2 phosphorylation are probably through inhibition of the N-methyl d-aspartate-mediated calcium influx, which subsequently reduce the hyperglycemia-exaggerated cerebral damage.     

Translocation of Enterococcus faecalis strains across a monolayer of polarized human enterocyte-like T84 cells

We used a two-chamber system to study transcytosis of Enterococcus faecalis across monolayers of human colon carcinoma-derived T84 cells, which show structural resemblance to the native intestine. Among 16 E. faecalis isolates from different sources, the well-characterized strain OG1RF and 8 other isolates (2 endocarditis isolates, 1 urine isolate, and all 5 fecal isolates) showed translocation in this assay, while 6 clinical isolates (3 endocarditis and 3 urine isolates), the recipient strain JH2-2, and the control, Escherichia coli DH5alpha, had no detectable translocation. Of two OG1RF mutants involving the previously studied epa (enterococcal polysaccharide antigen) gene cluster, known to be needed for virulence and resistance to killing by polymorphonuclear leukocytes, one epa mutant (TX5179) was unable to translocate, while TX5180, with an epa disruption farther downstream, showed a moderate decrease in translocation relative to that of the wild-type strain OG1RF (P < 0.01), indicating that the epa gene cluster is important for translocation across a T84 monolayer. This observation was confirmed by complementation of the epa mutant (TX5179) with epa genes and restoration of its translocation ability. In conclusion, we have demonstrated translocation of at least some strains of E. faecalis across T84 monolayers, although strains differ considerably in this ability, and we have demonstrated that epa mutations can cause marked changes in successful translocation. These results suggest that this model may be a useful in vitro system for studying the process of translocation from the intestinal tract.     

动脉粥样硬化斑块中内皮素生成及分布的免疫组织化学观察

应用免疫组化方法对人动脉粥样硬化（ＡＳ）斑块中内皮素（ＥＴ）进行分析，发现除内皮细胞外，增生的平滑肌细胞（ＳＭＣ）中也含有大量的内皮素；在内皮剥脱的大鼠胸主动脉，增生的内膜ＳＭＣ能产生丰富的内皮素。内皮素放射免疫测定证实ＳＭＣ增生的活跃程度与内皮素量呈正比。提示内皮素合成增多与ＡＳ斑块内ＳＭＣ增生关系密切。     

阿糖胞苷纳米粒的制备及其释药规律研究

采用乳化聚合法制备阿糖胞苷纳米粒，研究其体内外释药特性。结果表明阿糖胞苷纳米粒体外释药规律符合双指数方程，有明显的缓释作用。在家兔体内的药物动力学过程符合二室模型，与阿糖胞苷注射剂相比，t1／2β和MRT延长，CL降低，表明阿糖胞苷纳米粒可显著延长阿糖胞苷在体内存留时间，具有明显的缓释特征。     

巢蛋白和阶段特异性胚胎抗原-1在大鼠2型星形胶质细胞中的表达

目的 观察1型和2型星形胶质细胞(T1A、T2A)是否表达神经干细胞的标志物、是否具有神经干细胞的特性.方法 取新生大鼠脑皮质,体外培养纯化的O-2A祖细胞、T1A和T2A,应用激光共焦双重免疫荧光标记技术检测巢蛋白和阶段特异性胚胎抗原-1(SSEA-1)的表达;观察O-2A祖细胞、 T1A和T2A在碱性成纤维生长因子(bFGF)和表皮生长因子(EGF)的培养液中生长方式的改变.结果 巢蛋白在O-2A祖细胞和T2A中表达,T1A不表达;SSEA-1仅在T2A中表达.在干细胞培养基中培养10d,T2A形成能增殖和连续传代的细胞球,细胞球巢蛋白标记阳性,贴壁后分化细胞具有神经元、星形胶质细胞和少突胶质细胞样形态;但相同培养条件下的O-2A祖细胞和T1A生长方式无改变.结论 巢蛋白和SSEA-1在两型星形胶质细胞中的表达存在差异,T2A具有神经干细胞的某些生物学特性.     

钴60放射法制备免疫功能抑制大鼠模型

目的通过系统的钴60放射计划,对大鼠免疫功能抑制的合适剂量进行评估,为干细胞移植研究提供合适的的动物模型。方法SD大鼠随机分为12.5Gy、10Gy、7.5Gy、5Gy4个剂量组,10只/组。计算放射后2个月的死亡率。检测白细胞数量,评价各剂量组动物的白细胞参考值范围。结合死亡率和白细胞参考值范围,确定合适的放射剂量。通过对外周血中性粒细胞(PMN)吞噬实验和外周血白细胞移行抑制实验(MIT),对细胞免疫功能进行检测。结果行12.5Gy照射的大鼠,3d内全部死亡;10Gy放射后的大鼠在1个月内全部死亡;7.5Gy照射的大鼠2个月内死亡1只;5Gy照射的大鼠没有死亡情况发生。设定95%作为可信区间,计算白细胞数量参考值范围(109个/L),未放疗组:16.978+1.96×6.46;5Gy放疗组:4.93+1.96×0.72;7.5Gy放疗组:2.313+1.96×0.782;10Gy放疗组:1.03+1.96×0.507。t检验表明,随着放疗剂量的增加,各实验组的白细胞数量显著减少。对于细胞免疫功能的检测,外周血中性粒细胞(PMN)吞噬实验结果表明,机体全身免疫功能降低;外周血白细胞移行抑制实验(MIT)表明,机体T细胞免疫功能降低。结论7.5Gy可以一定程度上抑制大鼠的免疫功能,为合适的放疗剂量。