Polysaccharide-protein surface modification of titanium via a layer-by-layer technique: characterization and cell behaviour aspects

To improve the surface biocompatibility of titanium films, a layer-by-layer (LBL) self-assembly technique, based on the polyelectrolyte-mediated electrostatic adsorption of chitosan (Chi) and gelatin (Gel), was used leading to the formation of multilayers on the titanium thin film surfaces. The film growth was initialized by deposition of one layer of positively charged poly(ethylene imine) (PEI). Then the thin film was formed by the alternate deposition of negatively charged Gel and positively charged Chi utilizing electrostatic interactions. The LBL film growth was monitored by several techniques. The chemical composition, surface topography as well as wettability were investigated by using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), confocal laser scanning microscopy (CLSM) and water contact angle measurement, respectively. Quantitative XPS analysis showed the alternative change of C/N ratio after four sequential cycles coating of Ti/PEI/Gel/Chi/Gel, which indicated the discrete layer structure of coatings. Uncoated titanium (control sample) displayed a smooth surface morphology (root mean square (RMS) roughness was around 2.5 nm). A full coverage of coating with Gel/Chi layers was achieved on the titanium surface only after the deposition layers of PEI/(Gel/Chi)2. The PEI/Gel/(Chi/Gel)3 layer displayed a rough surface morphology with a tree-like structure (RMS roughness is around 82 nm). These results showed that titanium films could be modified with Chi/Gel which may affect the biocompatibility of the modified titanium films. To confirm this hypothesis, cell proliferation and cell viability of osteoblasts on LBL-modified titanium films as well as control samples were investigated in vitro. The proliferation of osteoblasts on modified titanium films was found to be greater than that on control (p<0.05) after 1 and 7 days culture, respectively. Cell viability measurement showed that the Chi/Gel-modified films have higher cell viability (p<0.05) than the control. These data suggest that Chi/Gel were successfully employed to surface engineer titanium via LBL technique, and enhanced its cell biocompatibility. The approach presented here may be exploited for fabrication of titanium-based implant surfaces.     

我国HIV-1 B''亚型毒株gag基因变异特征研究

目的研究我国人免疫缺陷病毒1型（HIV-1）B’亚型主要流行株在宿主免疫压力下的基因变异及抗原表位的变化特征，探讨选择压力、基因离散率和抗原表位变化之间的关系。方法从确诊的HIV-1感染者的全血样本中提取基因组DNA，经套式聚合酶链反应（PCR）扩增后，将扩增产物进行纯化和测序。然后将所得序列进行系统进化树和氨基酸变异分析，使用GCG软件包的Distance程序对P17和P24两个区段计算基因距离，用Diverge程序计算同义替换（1（s）和非同义替换（1（a）及二者之间的比值，并对我国人群中较常见的HLA型别限制的CTL表位的突变情况进行分析。结果HIV-1B’亚型毒株的P17区段的Ks／Ka值〈1，而P24区段的Ks／Ka值〉1；P24部分的基因离散率低于P17部分；P17区段抗原表位的保守率为34．94％，而P24区段抗原表位的保守率为67．38％；从基因离散率、所受的选择压力及抗原表位的突变率3个方面来看，HIV-1的P17区段均明显大于P24区段。结论HIV-1B’亚型毒株的P17区段的抗原表位变化较大，而P24区段的抗原表位相对较为保守。提示P24区段的CTL表位更适合于表位疫苗的研制。     

"军字1号"工程使用前后病案首页质量对照统计分析

为探讨“军字1号”工程使用前后的病案首页质量变化,本文通过作者所在医院近八年病案首页的质量调查统计,对“军字1号”工程使用前后的病案首页质量作了详细的对照分析比较,为进一步加强“军字1号”工程中的病案首页质量管理提供经验。     

NOD.Scid过继性1型糖尿病小鼠模型的建立

目的:建立能反应自身免疫特点的1型糖尿病动物模型,为进一步研究该病发病机理奠定基础。方法:将16只NOD.Scid小鼠随机分为两组,实验组小鼠腹腔注射发病NOD小鼠脾细胞,对照组注射未发病NOD小鼠脾细胞;每日测定血糖和体重;当出现重度糖尿病临床表现时处死,其余小鼠细胞过继后10周处死,经组织学观察和细胞因子ELISA测定。结果:实验组小鼠发病率为8/8,对照组为0/8;胰岛炎性积分分别为2.5±0.2,0;实验组IL-2、IL-10、IFN-γ水平分别为60.7pg/ml、15.5pg/ml、20.2ng/ml,对照组为2.4pg/ml、17.5pg/ml、3.2ng/ml。结论:在NOD.Scid小鼠体内一次性过继发病NOD小鼠脾细胞后5~10周可成功建立1型糖尿病的小鼠模型。     

Cytokines transduced bone marrow stromal cell lines promote immunohematopoietic reconstitution in mice after allogeneic bone marrow transplantation

Impaired immune reconstitution following allogeneic T-cell depleted bone marrow transplantation (allo-TCD-BMT) is a major obstacle to its clinical application. Stromal cell line QXMSC1, established from bone marrow cells of BALB/c(H-2d), was transfected with murine IL-3 and/ or IL-2 gene, and injected into lethally irradiated C57BL/6(H2b) mice. We evaluated its effects on immunologic and hematopoietic reconstitution after allo-TCD-BMT. The results showed that QXMSC1-IL-3 + IL-2 could significantly increase the numbers of hematopoietic primitive progenitors (CFU-S), committed progenitors (CFU-GM, and BFU-E), and lymphocytes (CD8+ cells, CD4+ cells, and B cells). Similarly, immune functions of recipient mice were significantly enhanced in the QXMSC1-IL-3 + IL-2 group. In addition, QXMSC1-IL-3 or QXMSC1-IL-2 also exerted apparent effects on accelerating immune reconstitution, but these effects were far less than that of QXMSC1-IL-3 + IL-2. Our results demonstrated that stromal cell-mediated IL-3 and IL-2 gene therapy may be a potent approach in promoting immunologic and hematopoietic reconstitution after allo-TCD-BMT.     

Effects of behavior modification on body image, depression and body fat in obese Korean elementary school children

This study was performed to investigate the effects of behavior modification on body image, depression and body fat in obese elementary school children. Sixty-two elementary students of the 4th to 6th grade were selected from two different Seoul schools. Thirty-four children in one school were designated as the experimental group, and 28 children from the other school as the control group. The experimental group received 60 - 70 minutes of behavior modification, once a week, for 8 weeks. The control group received neither management nor treatment. The results indicated a significant improvement of body image and a reduction in the increase rate of body fat for the experimental group. This finding strongly supports the theory that behavior modification can be used as an effective strategy in the treatment of obese children.     

趋化性细胞因子对人Tc1和Tc2细胞内Ca~(2+)浓度变化的影响

为了探讨趋化性细胞因子在体外对人Tc1和Tc2亚群细胞内Ca2 + 浓度变化的影响 ,从PBMC中分离纯化CD8+ T细胞 ,在特定细胞因子及细胞因子抗体作用下 ,体外定向诱导出能长期培养的Tc1和Tc2细胞系 ,用免疫荧光染色结合流式细胞术分析对其进行鉴定后 ,通过流式细胞术检测在趋化性细胞因子刺激前后 ,细胞内Ca2 + 浓度的变化。发现受SDF 1作用后 ,Tc1及Tc2细胞内Ca2 + 浓度变化均不明显 ,而IP 10刺激后 ,Tc1及Tc2细胞内Ca2 + 水平在短时间内明显上调 ,且在Tc1胞内的上升幅度远高于Tc2细胞 ,在MIP 1β刺激后 ,也观察到类似趋势 ;受Eotaxin刺激后 ,Tc1及Tc2细胞内Ca2 + 水平均有微小上升 ,在Tc2细胞内的上升幅度略高于Tc1细胞。说明Tc1和Tc2细胞受趋化性细胞因子作用后 ,细胞内Ca2 + 浓度有不同程度的变化 ,且与趋化性细胞因子受体的表达呈现一定的相关性。     

Toward Improving Caenorhabditis elegans Phenome Mapping With an ORFeome-Based RNAi Library

The recently completed Caenorhabditis elegans genome sequence allows application of high-throughput (HT) approaches for phenotypic analyses using RNA interference (RNAi). As large phenotypic data sets become available, “phenoclustering” strategies can be used to begin understanding the complex molecular networks involved in development and other biological processes. The current HT-RNAi resources represent a great asset for phenotypic profiling but are limited by lack of flexibility. For instance, existing resources do not take advantage of the latest improvements in RNAi technology, such as inducible hairpin RNAi. Here we show that a C. elegans ORFeome resource, generated with the Gateway cloning system, can be used as a starting point to generate alternative HT-RNAi resources with enhanced flexibility. The versatility inherent to the Gateway system suggests that additional HT-RNAi libraries can now be readily generated to perform gene knockdowns under various conditions, increasing the possibilities for phenome mapping in C. elegans.     

经皮锁定加压钢板固定胫骨多段骨折21例疗效分析

目的探讨经皮锁定加压钢板(locking compression plate,LCP)手术治疗胫骨多段骨折的临床疗效。方法将2010年6月~2011年12月收治的胫骨多段骨折患者,根据AO分类方法筛选出C2型骨折21例:左侧9例,右侧12例;男性14例,女性7例;年龄15~71岁,平均(44±2.1)岁。入选病例均采用微创经皮插入LCP钢板手术内固定治疗。结果随访8~15个月,术后3~4月骨折线变模糊,术后6~9月骨折处出现大量骨痂;膝关节屈曲为(147±3.2)°,伸直为(0±0.5)°;踝关节背伸(9±1.2)°,跖屈(43±2.1)°;Johner-Wruhs评分标准:优17例,良3例,可1例,差0例;优良率95.24%。结论经皮LCP钢板固定胫骨多段骨折安全、有效,是值得推广的手术方式。