PIII 改性ePTFE 膜对细菌生存状态的影响研究

目的:探讨等离子注入技术(Plasma immersion ion implantation,PⅢ)对膨体聚四氟乙烯(ePTFE)膜改性后表面性能以及对细菌生存状态的影响.方法:采用氧等离子注入技术(PⅢ)对ePTFE膜表面处理,获得改性ePTFE膜,利用扫描电镜(SEM)观察改性ePTFE膜和未处理膜的表面形貌,体外培养变形链球菌,观察改性前后各组膜作体外细菌生存状态变化.结果:与未处理ePTFE膜相比,改性ePTFE膜表面形貌、亲水性发生改变.荧光染色后观察长脉冲组表面的细菌最少;短脉冲组膜表面粘附的细菌密集,形成生物膜;空白组可见少量死菌和活菌粘附于ePTFE膜上.结论:长脉冲PⅢ改性ePTFE膜后有良好的抗细菌粘附能力.     

大鼠成骨细胞在聚乳酸、马来酸酐改性聚乳酸表面的粘附性能研究

采用微管吸吮装置对大鼠成骨细胞,在聚乳酸和马来酸酐改性聚乳酸材料表面的粘附性能进行了研究.目的是评价材料的粘附性能和改性方法,并筛选材料.研究表明：与玻璃材料相比,成骨细胞在聚乳酸表面的粘附力更大,经化学结构改性后,聚乳酸对成骨细胞24 h的粘附性能提高了近2倍.成骨细胞在改性聚乳酸材料表面的24 h组的粘附力是15 min组的1.3倍（测量时间为3 h）,而在聚乳酸上则差别不明显.实验证实,改性聚乳酸是一种更利于成骨细胞粘附的支撑材料,采用的改性方法可行.     

表面活性剂溴化十六烷基吡啶对 产膜表皮葡萄球菌粘附作用的影响

目的通过表面活性剂溴化十六烷基吡啶抗表皮葡萄球菌生物被膜菌粘附作用的研究,为临床针对产膜表皮葡萄球菌引起的相关感染提供可能的探索方向和防治途径。方法以万古霉素为阳性对照,利用XTT减低法,评价溴化十六烷基吡啶对表皮葡萄球菌初始粘附的影响。结果浓度为4、2和1 mg/L的溴化十六烷基吡啶对表皮葡萄球菌初始粘附均有显著的抑制作用,与阴性对照组比较差异有统计学意义(t=0.4555~34.9664,P0.01);用浓度为32、16、8和4 mg/L的溴化十六烷基吡啶对实验材料预处理后,对表皮葡萄球菌初始粘附抑制作用明显,与阴性对照组比较差异有统计学意义(t=1.1125~21.9246,P0.001)。结论溴化十六烷基吡啶无论是直接作用或是对实验材料预处理,对表皮葡萄球菌形成生物被膜的初始粘附过程具有显著抑制作用。     

一种等离子体浸没N+注入种子诱变植物的方法初探

针对离子生物学应用于探索生命过程和诱变育种、改良品种时,注入种子的离子出射方向必须垂直于种胚的表面,离子仅在与种子相互作用的区域产生自由基,即局部损伤效应的事实,本文采用等离子体浸没离子注入方法,毋需特意固定种子的位置,而是在真空室内通过激发的等离子体中形成大量的正、负离子,从各个方向击向种子表面进行离子注入,即可收到对种子表面的作用比较均匀一致的效果[余增亮等．安徽农学院学报,1991,18：251;科学前沿,1993,(4)：36;吴美萍等．上海农学院学报,1997,15：182]。实验材料为白花豌豆(Pisum tativum),由上海交通大学农学院提供。挑选大小均匀,综合性状良好的干种子在东华大学等离子体物理研究室进行等离子     

白色念珠菌对上皮细胞粘附性的观察

念珠菌性口腔炎是口腔的常见疾病 ,病原体以白色念珠菌多见。据报道 [1、2 ] ,口腔粘膜上皮细胞对念珠菌的粘附性与上皮细胞的分化程度有关。我们从健康人的口腔粘膜获取上皮细胞标本 ,与白色念珠菌混合孵育后 ,应用巴氏染色方法来观察念珠菌对各类上皮细胞的粘附性能。1　材料与方法1.1　粘膜上皮细胞的制备　选择 2 0例健康人 (男性 10名 ,女性 10名 ,年龄 30～ 4 0岁 ) ,用无菌棉拭子在口腔粘膜表面反复轻擦 ,将棉试子浸入无菌磷酸盐缓冲液内 (PBS;0、0 1mol/ L ,p H7、2 ) ,摇动棉拭子使上皮细胞落于 PBS中 ,细胞悬液离心 15 min(10…     

树鼩细菌感染模型的建立及抗菌药物的治疗效果评价(英文)

在抗微生物感染药物开发过程中, 动物模型是必不可少的。虽然目前已经用啮齿类动物建立了一些细菌感染动物模型, 但在小型灵长类动物中还很少见。这里首次报道两个树鼩细菌感染动物模型。第一种是在三度烫伤后的皮肤表面接种 5×106 CFU 的金黄色葡萄球菌构建的皮肤烫伤感染模型。这个数量的金黄色葡萄球菌可以造成 7 d 持续性感染, 并且在第 4天可以看到明显的炎症反应。第二种是用绿脓杆菌构建的涤纶补片感染模型, 接种 2×106 CFU 的绿脓杆菌同样可以引起持续 6 d 感染, 并在第三天在伤口处观察到大量的脓液。进一步用这两种模型评价头孢哌酮钠和左氧氟沙星的治疗效果。左氧氟沙星和头孢哌酮钠在皮肤烫伤感染模型中能分别将 100 mg 皮肤组织中的细菌降低到 4log10 和 5log10 CFU, 并且在涤纶补片植入感染模型中这两种抗生素都能显著地将感染的细菌降低了 4log10 CFU (P<0.05)。结果表明用金黄色葡萄球菌和绿脓杆菌成功构建了两个细菌感染的树鼩模型。此外, 树鼩对金黄色葡萄球菌和绿脓杆菌很敏感, 适合用于构建细菌感染动物模型和评价新的抗细菌感染药物的效果。     

载银纳米抗菌复合骨填充材料体外抗菌性能研究

目的探讨新型载银纳米抗菌复合骨填充材料(TiO2-Ag-nHA/PA66)的体外抗菌性能。方法采用抑菌环试验及菌落总数测定法检测不同纳米抗菌复合骨填充材料(A1、A2、A3)对金黄色葡萄球菌及大肠埃希菌的体外抗菌效果;扫描电镜观察其对细菌的抗粘附作用。结果抑菌环试验显示,不同载银纳米抗菌复合骨填充材料对金黄色葡萄球菌和大肠埃希菌均形成明显的抑菌环,以作用24 h抑菌环直径最大,并随作用时间延长,抑菌环直径逐渐缩小。其中银含量为0.64%(质量比)的材料A3的抗菌作用最明显,持续时间最长,其对金黄色葡萄球菌和大肠埃希菌的抑菌作用持续时间分别达到33 d和24 d;菌落总数测定法显示细菌与材料A3接触24 h后,对金黄色葡萄球菌和大肠埃希菌的抗菌率分别为94.18%和85.96%;扫描电镜发现载银材料能够明显减少细菌在材料表面的粘附。结论载银纳米抗菌复合骨填充材料体外对金黄色葡萄球菌及大肠埃希菌有明显抗菌作用,为其应用于慢性骨髓炎术后骨缺损修复提供理论依据。     

三株益生菌粘附性质及机制的初步研究

目的研究3株益生菌株的粘附性质,初步探讨细菌与肠细胞的粘附机制。方法选取已被深入研究的LGG作为阳性对照,应用显微观察和平板计数的方法测定3株乳杆菌和肠上皮细胞Caco-2的粘附,选择疏水性、表面电荷和自聚合能力3项指标来描述细菌的表面性质,应用粘附抑制试验和酵母凝集试验来测定糖类专一性粘附。结果无论是用显微观察还是平板计数,ST-Ⅲ均是所测试的4株菌中粘附能力最强的,当加入细菌和细胞比约为60∶1时,ST-Ⅲ在Caco-2上的粘附数为(7.43±0.65)CFU/细胞,强于对照菌LGG[(3.99±0.57)CFU/细胞]。在所测试的4株菌中,粘附能力和疏水性具有很好的相关性,同时自聚合能力对粘附也表现出一定的促进作用。除LGG外,D-甘露糖和甲基-α-D-甘露糖苷均能抑制另外3株乳杆菌的粘附,同时这3株乳杆菌也能不同程度地凝集酵母。结论3株益生菌的粘附均涉及到非特异性的疏水结合和甘露糖特异性粘附两个过程;ST-Ⅲ是1株具有良好粘附能力的益生菌,有待进一步的研究。     

BMSCs在PLGA-[ASP-PEG]基质材料表面粘附及增殖的研究

目的：探讨大鼠骨髓间充质干细胞BMSCs在聚丙交酯/乙交酯/天冬氨酸-聚乙二醇三嵌段多元共聚物 PLGA-[ASP-PEG]表面粘附、增殖的情况,为组织工程学体外诱导种子细胞生长提供新的生物材料。方法：在PLGA支架材料中引入聚乙二醇（PEG）和含有多个功能位点的天冬氨酸（ASP）,制成PLGA-[ASP-PEG]高分子支架材料。 将PLGA-[ASP-PEG]支架材料与BMSCs复合培养,以未改性的PLGA支架材料作对照,通过沉淀法、MTT法和考马斯亮蓝法分别检测BMSCs的粘附和增殖变化;扫描电镜观察黏附细胞的形态。结果 BMSCs在PLGA-[ASP-PEG]材料表面帖壁生长,细胞数目明显多于单纯PLGA组。细胞粘附率检测显示：改性后的PLGA-[ASP-PEG]表面BMSCs的粘附性能和增殖能力明显高于对照组,P＜0.05。MTT比色试验,BMSCs在三嵌段材料上培养20d后,吸光值A=1.336,约为对照组0.780的两倍。细胞内蛋白总量间接反映细胞黏附及增殖情况。培养12d时,在PLGA-[ASP-PEG]材料组细胞的蛋白含量为66.44μg/孔,单纯PLGA组为41.23μg/孔,间接说明了三嵌段材料生物相容性好,细胞黏附力强的特点。结论PLGA-[ASP-PEG]能促进组织工程种子细胞在骨基质材料表面的黏附、增殖并能较好地保持细胞的形态。     

基于海藻酸钠羟基改性的MPEG原位共价修饰微胶囊及抗蛋白性能

目的:通过对海藻酸钠链段羟基位点改性制备甲氧基聚乙二醇(MPEG)原位共价修饰的海藻酸钠/壳聚糖(AC)微胶囊,在保证MPEG修饰微胶囊机械强度不受影响的基础上,有效提高表面MPEG修饰密度,实现兼具良好机械稳定性及抗蛋白性能的微胶囊制备方法。方法:利用溴化氰对海藻酸钠羟基进行活化并将末端氨基的点击化学linker(BAT)接枝在主链上进而制备MPEG原位共价修饰微囊A_(B(OH))CP_N,用球磨法表征微囊机械强度,用Ig G和Fgn为模型考察微囊表面抗蛋白吸附性能,以L929细胞在其二维模拟平板膜上的黏附情况作为衡量指标,考察MPEG修饰微胶囊表面细胞粘附情况,并最终通过体内移植考察MPEG修饰微囊的生物相容性。结果:基于海藻酸钠羟基位点的MPEG原位共价修饰微胶囊能够实现与常规条件制备的微胶囊接近的机械强度;同时与对照组相比Ig G吸附量降低87.4%,Fgn吸附量降低75.5%,实现了良好的抗蛋白吸附性能;二维模拟平板膜表面L929细胞粘附情况显著改善,细胞粘附数与对照组相比降低了76.9%;体内移植结果证明MPEG修饰微囊细胞粘附极少,微囊与纤维层分离明显。结论:基于海藻酸钠羟基位点的MPEG原位修饰能够实现兼具良好机械稳定性及抗蛋白吸附性能的微胶囊。     

A preliminary investigation on the chemical composition of the cell surface of five enteropathogenic Escherichia coli serotypes.

The cell surfaces of five enteropathogenic Escherichia coli serotypes (O111:H2; O111:H12; O125:H9; O119:H6; O26:H11) were assayed by chemical methods, lectin agglutination tests and spectroscopy associated to transmission electron microscopy. Results of lectin agglutination assays showed that all strains reacted with mannosebinding lectins. Strains belonging to serotype O125:H9 also agglutinated with lectins which recognize galactose and Nacetylgalactosamine residues. The bacterial cells were treated with 0.01M phosphate buffered saline (pH 7.0) at 100 degree C for 2 hr and the extracts were submitted to precipitation and fractionated by Cetavlon. Phosphate, total sugar and protein contents were determined. Gas liquid chomatography-mass spectrometry analysis of alditol acetates showed the presence of galactose, mannose, fucose, glucose and traces of ribose. Spectroscopic analysis of intact cells showed the presence of a capsule-like structure which was not totally preserved after extraction. Some cells were still surrounded by an amorphous capsular-like material after polysaccharide extraction.     

The fate of E. coli lipopolysaccharide after the uptake of E. coli by murine macrophages in vitro

The fate of bacterial lipopolysaccharide (LPS) after the uptake of Escherichia coli by macrophages in vitro was studied. The LPS of the galactose epimerase-deficient E. coli J5 mutant was specifically radiolabeled with [3H]galactose by growing the organism in a basic salts medium containing galactose. Control bacteria were uniformly radiolabeled by growth in [14C]glucose and unlabeled galactose-containing medium. Surface constituents of E. coli were also labeled with 125I. After in vitro phagocytosis of labeled E. coli by murine peritoneal exudate macrophages, the rate of exocytosis of LPS, as assessed by release of 3H over a 72-hr period, was considerably reduced in comparison with other bacterial constituents (14C and 125I release). The [3H]galactose-labeled material exocytosed from macrophages and that remaining intracellularly (obtained from macrophage lysates) were isolated by cesium chloride (CsCl) density gradients and were shown to have altered density profiles as compared with purified E. coli LPS. The macrophage-"processed" [3H] galactose-containing fractions from CsCl density gradients of culture supernatants or macrophage lysates were capable of clotting Limulus amebocyte lysate. The [3H]galactose material obtained from 48-hr macrophage lysates and culture supernatants could also induce a lethal response in actinomycin D-treated mice. These data suggest that bacterial LPS may be selectively retained by the macrophage and that the post-phagocytic events that result in bacterial degradation are not accompanied by the degradation of LPS. Furthermore, although the LPS may be modified by the macrophage, it retains its biologic activity.     

Increased endothelial cell adhesion on plasma modified nanostructured polymeric and metallic surfaces for vascular stent applications

Techniques to regenerate the vasculature have risen considerably over the last few decades due to the increased clinical diagnosis of artery narrowing and blood vessel blockage. Although initially re‐establishing blood flow, current small diameter vascular regenerative materials often eventually cause thrombosis and restenosis due to a lack of initial endothelial cell coverage on such materials. The objective of this in vitro study was to evaluate commonly used vascular materials (specifically, polyethylene terephthalate, polytetrafluoroethylene, polyvinyl chloride, polyurethane, nylon, commercially pure titanium, and a titanium alloy (Ti6Al4V)) modified using an ionic plasma deposition (IPD) process and a nitrogen ion implantation plasma deposition (NIIPD) process. Such surface modifications have been previously shown to create nanostructured surface features which mimic the natural nanostructured surface features of blood vessels. The modified and unmodified surfaces were characterized by scanning electron microscopy, atomic force microscopy and surface energy measurements. Furthermore, in vitro endothelial cell adhesion tests (a key first step for vascular material endothelialization) demonstrated increased endothelial cell adhesion on many modified (with IPD and NIIPD + IPD) compared to unmodified samples. In general, endothelial cell adhesion increased with nanoroughness and surface energy but demonstrated a decreased endothelial cell adhesion trend after an optimal coating surface energy value was reached. Thus, results from this study provided materials and a versatile surface modification process that can potentially increase endothelialization faster than current unmodified (conventional) polymer and metallic vascular materials. Biotechnol. Bioeng. 2009;103: 459–471. © 2009 Wiley Periodicals, Inc.     

Radioimmunoassay of rat apolipoprotein B peptides in lipoproteins and tissues

Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE) separates rat apolipoprotein B (apoB) into one lower and two higher molecular weight components. Of the latter, peptide I (PI) corresponds to human B-100, while the slightly faster-migrating peptide II (PII) lacks a human counterpart; the smaller species peptide III (PIII) corresponds to human B-48. We describe here a competitive radioimmunoassay which separately measures the amounts of total (i.e., PI + PII + PIII) and larger (i.e., PI + PII) rat apoB peptides, with the amounts of PIII obtained by difference. Standard rat PIII and combined PI + PII (PI,II) were isolated by high-pressure gel filtration liquid chromatography in the presence of SDS, and the PI,II was used as an immunogen to raise rabbit antisera which were capable of binding all three forms of rat apoB. However, Scatchard analysis showed this binding to represent two distinct types of antibodies: one high-affinity class which bound only PI,II and a second class which bound all apoB peptides with equal but lower affinity. Thus, since 125I-labeled PIII was displaced equally effectively by PI,II and PIII, but 125I-labeled PI,II was displaced only by PI,II, the unabsorbed antiserum could be used to measure either total apoB or PI,II alone, depending on the choice of labeled ligand. The validity of the assay for apoB peptides in very-low-density and low-density lipoproteins and in liver microsomes was verified by comparison with peptide determinations by SDS-PAGE.     

类金刚石薄膜的制备及其血液相容性的初步研究

本文以单晶硅为基体,Ar等离子体对基体进行清洗,用法制备类金刚石(DLC)膜和掺氮的DLC膜。沉积DLC膜所用的气体是乙炔和氩气,沉积掺氮的DLC膜用乙炔和氮气。利用衰减全反射红外光谱(ATR-FTIR)和扫描电子显徽镜(SEM)对沉积的DLC膜和掺氮的DLC膜进行结构分析和观察表面形貌。考察了乙炔比例、放电功率等沉积参数对DLC膜的影响。通过接触角和血小板黏附实验,进行了DLC膜的抗凝血性能分析,效果较好。     

Facile platelet adhesion to collagen requires metabolic energy and actin polymerization and evokes intracellular free calcium mobilization

The attachment of platelets to collagen-coated microtiter plates at 20 degrees C was inhibited strongly by depletion of metabolic energy or by addition of cytochalasins and was slightly inhibited by the intracellular Ca2+ chelator BAPTA. In keeping with their respective potencies as inhibitors of actin polymerization, cytochalasins D and H were the most potent inhibitors of adhesion, while cytochalasin B was the least potent. Energy depletion, cytochalasin D or, to a much lesser extent, BAPTA also inhibited platelet adhesion to collagen in a suspension assay system at 37 degrees C. Collagen-induced platelet cytosolic Ca2+ mobilization was inhibited up to 70% by cytochalasin D and abolished by energy depletion or BAPTA. Elevation of intracellular platelet calcium by treatment with ionomycin had little effect on platelet adhesion to collagen. We propose that rapid platelet spreading along collagen fibers is both energy- and actin-dependent and necessary to produce maximal adhesion needed to elicit Ca2+ mobilization required for subsequent responses.     

Effect of diethylsulphoxide on growth,survival and ion exchange of Escherichia coli

AIMS: To study the effect of diethylsulphoxide (DESO) on Escherichia coli growth, survival and ionic exchange in comparison with dimethylsulphoxide (DMSO). METHODS AND RESULTS: Bacterial survival was estimated by counting colony-forming units and by the most probable number (five-tube) technique; the K+ and H+ transport and H(2) formation were determined electrochemically. Diethylsulphoxide at concentrations between 0.01 and 0.5% (w/v) stimulated and above 5% decreased the anaerobic growth rate and survival. 2H+ : K+ exchange and H(2) formation were lost at 5% DESO. At 0.05% DESO the kinetic characteristics of H+ : K+ exchange and H(2) formation were typical for Delta micro (H(+)) -dependent TrkA uncoupled with F(0)F(1) under respiration. CONCLUSIONS: Diethylsulphoxide at low concentrations serves as an electron acceptor for an anaerobic respiratory chain stimulating bacterial growth and survival through the modulation of H+ : K+ exchange and H(2) formation activity. The effects of DESO were more pronounced than those of DMSO. SIGNIFICANCE AND IMPACT OF THE STUDY: Diethylsulphoxide determines essential biological and therapeutic properties that make its application preferable.     

Attachment of Pseudomonas fluorescens to glass and influence of electrolytes on bacterium-substratum separation distance.

The influence of Na+, Ca2+, La3+, and Fe3+ on the adhesion of Pseudomonas fluorescens H2 and H2S was investigated with interference reflection microscopy (IRM). IRM is a light microscopy technique which allows (i) visualization of the adhesive sites of living bacteria as they attach to a glass cover slip surface and (ii) evaluation of the bacterium-glass surface separation distance within a range of 0 to ca. 100 nm. The addition of each cation caused changes in IRM images consistent with a decrease in the separation distance, and minimum effective concentrations were as follows: Na+, 1 mM; Ca2+, 1 mM; La3+, 50 microM; and Fe3+, 50 microM. With strain H2, the effects of Na+, Ca2+, and La3+ were fully reversible in that the separation distance increased again when the electrolyte was replaced with distilled water. However, with strain H2S, a spontaneous mutant of H2 with increased attachment ability, only the effect of Na+ was fully reversible, and the effects of Ca2+ and La3+ were only partially reversible or irreversible. The effect of Fe3+ was irreversible with both strains, but this may be related not only to the electrolytic nature of Fe3+ but also to the decrease in solution pH to 3.5 caused by its addition. It is proposed that the electrolytes caused a decrease in separation distance by neutralizing negative charges on bacterial surface polymers and that the different effects obtained with the two strains are related to their different adhesion abilities.