兔心窦房结的亚微结构观察

本文观查了8例杂种成免心脏窦房结的亚微结构。窦房结主要由P细胞和T细胞构成。P细胞多成团存在。细胞圆形或多边形,胞核大,可见双核细胞;胞质内肌原纤维和线粒体较少;核糖体、糖原颗粒、高尔基氏器、粗面和滑面内质网均较丰富;高尔基氏器附近有电子密度较高的球形颗粒;胞膜下见到许多小凹和小囊;P细胞间有散在的中间连接。T细胞的形态和结构介于P细胞和心肌细胞之间。最后对窦房结内各细胞的功能特点加以讨论。     

抗T细胞单克隆抗体对再生障碍性贫血患者TNF和IL—2水平的影响

为探讨抗Ｔ淋巴细胞克隆抗体对再生障碍性贫血患者免疫功能的调节作用，采用放射免疫检测２５例ＡＡ患者ＭｃＡｂ－Ｔ治疗前后血清肿瘤坏死因子和白细胞介素－２（ＩＬ－２）水平及其中１０例周围血单个核细胞体外诱生ＴＮＦ和ＩＬ－２水平的变化。     

Two cis-acting elements in negative RNA strand of Hepatitis C virus involved in synthesis of positive RNA strand in vitro

Sequences at the 3'-ends of both positive and negative strands of Hepatitis C virus (HCV) RNA harbor cis-acting elements required for RNA replication. However, little is known about the properties of the negative RNA strand as a template for the synthesis of positive RNA strand. In this study, a purified recombinant HCV RNA-dependent RNA polymerase (RdRp) was used to investigate the synthesis of positive RNA strand using the 3'-terminal region of negative RNA strand ((-)3'T RNA) as template. A mutagenesis analysis was performed to evaluate the role of the 3'-proximal stem-loop and the first 3'-cytidylate (3'C) of the negative RNA strand in the synthesis of the positive RNA strand. A negative RNA strand of wild type (wt) HCV as template was able to direct the synthesis of a full-length positive RNA strand. Deletion of the 3'-proximal stem-loop resulted in an approximately 90% decrease in RNA synthesis. Disruption of the 3'-proximal stem-loop structure by nucleotide substitutions led to a 70-80% decrease in RNA synthesis. However, the restoration of the stem-loop by compensatory mutations in the stem region restored also the RNA synthesis. Likewise, the deletion or substitution of the first 3'C by guanylate (G) led to a 90% decrease in the RNA synthesis; while the substitution by adenylate (A) or uridylate (U) resulted in a 60-80% decrease in the RNA synthesis only. These findings demonstrate that the 3'-proximal stem-loop and the first 3'C of the negative RNA strand of HCV are two cis-acting elements involved in the synthesis of the positive RNA strand.     

聚醚型聚氨酯材料表面纤维蛋白原的吸附性研究

本文采用放射性同位素标记的方法研究了嵌段聚醚型聚氨酯在纯纤维蛋白原溶液中和稀释血浆中的表面纤维蛋白原吸附性规律，考察了聚醚型聚氨酯的特性粘数及溶液体系中的ＮａＣｌ浓度对材料表面纤维蛋白原吸附性的影响，结果表明，随着聚合物特性粘数的增大，材料表面的纤维蛋白原吸附量呈降低的趋势；溶液体系中盐浓度的降低导致纤维蛋白原凝固性增强，在纯纤维蛋白原溶液中，材料表面纤维蛋白原的吸附量相应增多，而在稀释血浆中，纤维蛋白原的吸附量相应减少，在达到最低值后又有上升的趋向，表明纤维蛋白原在材料表面的吸附还受血浆中其它大分子的影响。     

Effect of biologically active coating on biocompatibility of Nitinol devices designed for the closure of intra-atrial communications

Anti-thrombogenicity and rapid endothelialisation are prerequisites for the use of closure devices of intra-atrial communications in order to reduce the risk of cerebral embolism. The purpose of this study was therefore to assess the effect of bioactive coatings on biocompatibility of Nitinol coils designed for the closure of intra-atrial communications. Nitinol coils (n = 10, each) and flat Nitinol bands (n = 3, each) were treated by basic coating with poly(amino-p-xylylene-co-p-xylylene) and then coated with either heparin, r-hirudin or fibronectin. Anti-thrombogenicity was studied in vitro in a dynamic model with whole blood by partial thromboplastin time (PTT), platelet binding and thrombin generation, respectively, and cytotoxicity by hemolysis. Endothelialisation was studied on Nitinol bands with human umbilical venous endothelial cells (HUVEC) by 3-(4,5-dimethylthiazole-2yl)-2,5-triphenyl tetrazolium (MTT) assay and immnuofluorescence analysis of Ki67, vinculin, fibronectin and von Willebrand Factor. Uncoated or coated devices did not influence hemolysis and PTT. r-Hirudin (but not heparin) and fibronectin coating showed lower platelet binding than uncoated Nitinol (p < 0.005, respectively). Heparin and r-hirudin coating reduced thrombin formation (p < 0.05 versus Nitinol, respectively). HUVEC adhesion, proliferation, and matrix formation decreased in the order: fibronectin coating > uncoated Nitinol > r-hirudin coating > heparin coating > basic coating. MTT assay corroborated these findings. In conclusion, r-hirudin and fibronectin coating, by causing no acute cytotoxicity, decreasing thrombogenicity and increasing endothelialisation improve in vitro biocompatibility of Nitinol devices designed for the closure of intra-atrial communications.     

Stereoselective determination of cetirizine and studies on pharmacokinetics in rat plasma

Enantiomers may confer benefits over racemates in therapeutic uses and we developed a chiral separation method of cetirizine enantiomers, a second generation H1 histamine receptor antagonist, in rat plasma. alpha1-Acidglycoprotein based chiral stationary phase(AGP-CSP), monitored with UV at 230 nm was used to separate the enantiomers. Observed enantioselectivity (alpha) was 2.0. The AGP-CSP was also used at a preparative scale to isolate the enantiomers with an optical purity of greater than ee 99%. In addition, an analysis was carried out for the cetirizine enantiomers in rat plasma to study the differences of enantiomers in pharmacokinetics. Both (+)- and (-)-cetirizine were separated using a reversed-phase column of AGP, and were detected at the range of 2.5-200 microg ml(-1) in plasma. Although there was no recognizable differences in pharmacokinetics between the enantiomers in rat, the method appears to be useful for their pharmacokinetic studies.     

多发性骨髓瘤患者血清IL-6活性与急性相蛋白浓度的相关性研究

运用敏感的B_9细胞增殖试验检测了81例多发性骨髓瘤(MM)患者血清IL-6活性,同时分析了标本的几种急性相蛋白含量,结果表明,68％MM患者血清中IL-6活性大于5μ/ml(正常对照为5μ/ml以下),几种急性相蛋白中C-反应性蛋白(CRP)在MM时升高(P<0.01),平均达正常对照组的17倍以上,MM患者补体C_4与正常对照组无差异(p>0.05),C_3、白蛋白及转铁蛋白在MM时分别比正常下降24.42％、38.83％和32.80％,且与疾病分期有关,在血清IL-6大于5μ/ml的55例中,IL-6活性与CRP、C_3、白蛋白的相关系数分别为0.46,-0.34和-0.29,IL-6与转铁蛋白浓度相关不明显。本文结果提示:CRP、C_3及白蛋白等含量的变化可作为反映MM病情的简易而敏感的指标。     

氧分压在体监测仪的研制

作者报道一种稳定性较高的氧分压在体监测，为医学研究、临床诊断提供一种新的可靠的测试方法及设备，具有较大的应用价值。     

大白鼠前脑、脑干和小脑向孤束核的纤维投射——HRP法和ARG法研究

本实验用HRP法、WGA—HRP法和ARG法进一步研究了大白鼠前脑、脑干和小脑向孤束核的纤维投射及其局部定位关系。作者发现皮质32及8区、三叉神经脊束核尾侧亚核投射到孤束核头段;皮质24及8a区、三叉神经脊束核尾侧亚核投射到孤束核中段;皮质23及13区,中脑导水管周围灰质和三叉神经脊束核尾侧亚核投射到孤束核尾段。此外,结果还证明室旁核、下丘脑外侧区、兰斑核、K—F氏核、小脑顶核、中缝大核、网状大细胞核、外侧网状核、及延髓网状结构向孤束核的纤维投射,均存在着一定的局部定位关系。本文结合前脑、脑干向孤束核的纤维投射讨论了内脏活动调节及针刺镇痛效应的中枢机理并对大白鼠孤束核的分段(头、中及尾段)标准提出了新建议。     

Integrins and adhesion molecules: Tumour necrosis factor-{alpha}-mediated dyscohesion of epithelial cells is associated with disordered expression of cadherin/{beta}-catenin and disassembly of actin filaments

Tumour necrosis factor (TNF)- induced, in a time- and dose-dependentfashion, dyscohesion (cell-cell dissociation) of the endometrialepithelial cells. TNF- impaired the ability of cells to aggregateand to attain compaction. The cell-cell adherent junction isa specialized region of the plasma membrane where cadherin moleculesact as adhesion molecules and actin filaments are densely associatedwith the plasma membrane through a well-developed plasmalemmalundercoat. Dyscohesion induced by TNF- was associated with thedisordered expression of cadherin\-catenin at the sites of cell-cellcontact. In addition, within the time-frame that dyscohesionwas induced, TNF- down-regulated the expression of actin mRNAonly at 100 ng/ml without modulating the overall amount of actinprotein, its -isoform or the amount of ribosylated actin. However,TNF--mediated dyscohesion of epithelial cells was associatedwith loss of plasmalemmal undercoat as well as intracytoplasmicaggregates of F-actin and a simultaneous increase in G-actin.The effect of cytochalasin-B, which disrupts actin filamentson cell-cell binding, was less pronounced than the effect ofTNF-, suggesting that the effect of this cytokine on dyscohesionis not solely dependent on the disassembly of actin filaments.These findings show that the induction of disordered expressionof adhesion molecules, as well as disassembly of actin filaments,are implicated in the dyscohesion induced by TNF-.