钛合金和钴铬合金表面白色念珠菌粘附的研究

目的比较钛合金(Ti-6Al-4V)和钴铬合金(Chromium-Cobaltalloy)表面白色念珠菌粘附能力的大小,研究表面粗糙度与细菌粘附的关系。方法将不同表面粗糙度的钛合金和钴铬合金试件进行白色念珠菌体外粘附试验,采用菌落形成计数法测定试件表面的细菌粘附量。结果各钛合金试件组的细菌粘附量均少于相同表面粗糙度的钴铬合金试件组,两种金属试件表面的细菌粘附量均随表面粗糙度的增大而增加。结论钛合金较钴铬合金更能减少由白色念珠菌引起的义齿性口炎等并发症,同时修复体表面严格的研磨抛光也能有效减少这些并发症。     

3种义齿清洁剂对3种活动义齿材料表面白色假丝酵母菌抑菌效果的比较

目的比较保丽净、高乐氏、洗必泰对不同活动性义齿表面白色假丝酵母菌的抑菌效果。方法分别制备带白色假丝酵母菌的钴铬基托试件、纯钛基托试件、热凝树脂基托试件,并分别浸泡于洗必泰、保丽净、高乐氏溶液中6h,评价上述3种义齿清洁剂的抑菌效果。结果同一清洁剂的不同基托间比较细菌下降率差异无统计学意义(F=0.02,P0.05);同一基托经过不同清洁剂处理,细菌下降率差异有统计学意义(F=8.04,P0.05);钴铬基托、纯钛基托、热凝树脂基托的除菌效果均为保丽净最高,洗必泰最低,差异均有统计学意义(P0.05)。结论保丽净可有效减少细菌滋生,可作为理想的活动性义齿清洁剂长期使用。     

载银纳米二氧化钛树脂基托对口腔变形链球菌、白色念珠菌和血链球菌的影响

目的研究载银纳米二氧化钛(Ag-TiO2)树脂基托对变形链球菌和白色念珠菌的体外抗菌效果,同时研究其对口腔有益菌血链球菌的影响。方法将不同质量分数的载银纳米二氧化钛抗菌粉剂添加到树脂基托材料中,制成抗菌树脂基托。采用薄膜密贴法分别检测该抗菌树脂基托对变形链球菌、白色念珠菌和血链球菌的抗菌率。结果与空白对照相比,Ag-TiO2质量分数为2.0%时,抗菌树脂基托对变形链球菌的抗菌率达95.0%,当质量分数达到3.0%时,抗菌率达到99.0%;Ag-TiO2质量分数为3.0%时,抗菌树脂基对白色念珠菌抗菌率达90.0%以上,但当Ag-TiO2质量分数达到5.0%时,仍未达到强抗菌作用;含Ag-TiO2的抗菌树脂基托对口腔有益菌血链球菌也存在一定的抑制作用,当Ag-TiO2质量分数达到5.0%,时抗菌树脂基托对变形链球菌的抗菌率达到51.6%。结论质量分数为3.0%的载银纳米二氧化钛树脂基托对变形链球菌、白色念珠菌均有抑制作用,对口腔血链球菌的杀灭作用不强,3.0%的浓度在既能杀死致病菌的同时又能最大程度保护口腔有益菌,可以很大程度上保证口腔微生态的平衡。     

肺炎链球菌粘附机制的研究现状

肺炎链球菌粘附宿主我肺炎链球菌侵袭、感染宿主细胞的先决条件。粘附过程是特异的,是细菌表面的粘附分子和宿主细胞膜受体相互作用的结果。英膜对肺炎链球菌的粘附无影响,而细胞壁（ＣＷ）在介导肺炎链附粘附宿主细胞过程中起重要作用;ＣＷ亚组人脂磷酸（ＬＴＡ）介导肺炎链球菌的粘附过程,并导致炎症反应;细菌表面的结构蛋白或分泌蛋白是细菌与宿主细胞连接的桥梁;肺炎链球菌能与宿主细胞外基质蛋白特异性结合,进而粘附宿主     

伊犁黑蜂蜂胶对口腔主要致龋细菌及生物膜生长的实验研究

目的研究伊犁黑蜂蜂胶对口腔常见致龋细菌及其生物膜生长的影响,观察其防龋效果。方法 (1)通过液体稀释法测定伊犁黑蜂蜂胶对口腔常见致龋菌的最小抑菌浓度(MIC)及最小杀菌浓度(MBC);(2)生物膜形成抑制试验测定伊犁黑蜂蜂胶对口腔常见致龋菌的最小生物膜形成抑制浓度(MBIC50);(3)通过结晶紫染色法测定伊犁黑蜂蜂胶对口腔常见致龋菌的最小生物膜清除浓度(MBEC);结果(1)伊犁黑蜂蜂胶对变形链球菌、远缘链球菌、嗜酸乳杆菌、血链球菌、粘性放线菌和内氏放线菌的最低抑菌浓度分别是0.78、0.39、1.56、0.39、0.20和0.20 mg/mL,最低杀菌浓度分别为1.56、0.78、3.125、0.78、0.39和0.39mg/mL;(2)伊犁黑蜂蜂胶对变形链球菌、远缘链球菌、血链球菌、粘性放线菌和内氏放线菌的MBIC50分别是0.39、0.39、0.39、0.05和0.10mg/mL;(3)伊犁黑蜂蜂胶对变形链球菌、远缘链球菌、血链球菌、粘性放线菌和内氏放线菌的MBEC分别是6.25、1.56、3.1256、0.78和0.78mg/mL。结论伊犁黑蜂蜂胶对口腔主要致龋细菌的生长具有抑制作用,能够抑制主要致龋细菌单菌生物膜的形成,并具有一定清除作用,是具有一定防龋效果的天然药物。     

纳米银水凝胶涂膜干预气管导管表面铜绿假单胞菌黏附及生物膜形成的实验研究

目的研究纳米银水凝胶涂膜对气管导管（endotracheal tube,ETT）表面铜绿假单胞菌粘附及细菌生物膜（biofilm,BF）形成的干预作用。方法实验共设6组,分别为空白对照组,涂纳米银3．5、7．0、10．5、14．0和17．5μg／cm^2组。参考Brown平板法,制备ETT、表面铜绿假单胞菌BF模型。通过超声振荡-平板菌落计数法检测体外培养6、12、18h时各组ETT表面BF中的活细菌粘附数量。借助激光共聚焦显微镜观察BF中的活死菌分布情况,并测量BF厚度。结果（1）与空白对照组相比,最小量涂膜组（3．5μg／cm^2）体外培养6h时,导管表面活细菌的粘附量显著减少（P〈0．05）,12h时差异无显著性（P〉0．05）;最大量涂膜组（17．5μg／cm^2）体外培养6h时,ETT表面几乎未见细菌粘附（P〈0．05）,18h时BF中的活菌数量及BF厚度均显著减少（P〈0．05）。（2）激光共聚焦显微镜观察可见,培养6h时,空白对照组ETT表面粘附的死活菌呈不规则散点样分布,未见明显的细菌菌落形成,而各实验组ETT表面仅有细菌零星分布,其数量少于空白组。18h时空白对照组表面可见大量活死菌堆积粘连,有小菌落形成并相互交通成地图状,可见典型BF结构,而此时最大量涂膜组（17．5μg／cm^2）表面仅见数量不等的菌落形成,菌落周围可见数量不等的细菌分布。结论纳米银水凝胶涂膜可有效减少ETT表面铜绿假单胞菌的粘附数量,延缓导管表面细菌BF形成,其作用强弱随培养时间及单位面积中的纳米银剂量的变化而变化。     

三种树脂粘接剂对纯氧化铝粘接强度的影响

目的:测定试件经过喷砂、硅溶胶热处理及与硅烷偶联剂结合的表面处理后,三种树脂粘接剂与纯氧化铝贴面的剪切强度。方法:选取高纯度的α-Al_2O_3纯氧化铝试件30个,将其随机分为A(可乐丽菲露SACTM复合树脂粘接剂)、B(Vorilink N树脂粘接剂)、C(RelyXTM Unicem树脂粘接剂)三组,每组10个。与试件粘接,在恒温水浴37℃的环境下静置24 h后测试其剪切粘接强度。扫描电子显微镜下观察各试件粘接界面的破坏形式。结果:Vorilink N粘接强度为(18.37±2.11)、RelyXTM Unicem粘接强度为(9.98±1.22),SACTM树脂粘接材料粘接强度最好,为(25.91±2.97),显著高于Vorilink N树脂粘接剂和RelyXTM Unicem树脂粘接剂,差异具有统计学意义(P0.05)。A组全部为混合破坏,B组出现了粘接剂的内部破坏,C组既有混合破坏也有界面破坏和粘接剂的内部破坏。扫描电镜图显示A、B两组的粘接断面上有很多树脂残留,C组表面相对光滑树脂残留很少。结论:不同树脂粘接剂对纯氧化铝试件的粘接强度有影响,SACTM粘接剂的粘接效果最好。     

冷泉细菌Paenibacillus algorifonticola产抑菌活性物质提取分离工艺的研究

本文对冷泉细菌——Paenibacillus algorifonticola的代谢产物的提取分离进行了研究。P.algorifonticola可产生抑制白色念珠菌的水溶性物质。大孔树脂D101和XAD7HP串联使用脱除P.algorifonticola发酵液中的色素,树脂与发酵液比例为1∶10(g/mL)为佳。脱色后发酵液中的活性物质可被强酸性阳离子交换树脂FPC22H吸附,0.5 mol/L的氨水可将活性物质洗脱下来,每10 g FPC22H可以吸附120 mL发酵液中的活性物质。本文研究结果为进一步分离纯化P.algorifonticola产抗白色念珠菌物质奠定了基础。     

口腔链球菌摄取生物素与口内白色念珠菌生长的关系

为了探讨口腔细菌生态平衡机制,本文体外检测了４株口腔链球菌（Ｓ．ｓａｌｉｖａｒｉｕｓ,Ｓ．ｓａｎｇｕｉｓ,Ｓ．ｍｕｔａｎｓ和Ｓ．ｍｉｔｉｏｒ）和白色念珠菌生长对生物素的依赖性。结果显示白色念珠菌和口腔链球菌的生长绝对依赖生物素,前者最大半数生长需要生物素约１０ｐＭｏｌ／Ｌ,其最大生长率所需生物素约为１００ｐＭｏｌ／Ｌ;而后者最大半数生长需生物素为５２５ｐＭｏｌ／Ｌ。正常人血清和唾液中生物素的含量约为２１２２９４ｐＭｏｌ／Ｌ。生物素饥饿状态下的白色念珠菌和口腔链球菌,以及唾液离心沉淀物（绝大多数为细菌）摄取生物素具温度依赖性,而代谢抑制剂（叠氮化合物、氰化物和醋酸碘）和某些抗生素（杆菌肽、短杆菌肽、万古霉素和二性霉素）具选择性抑制效应,提示生物素的摄取和跨膜转运是一依赖能量的主动过程。用唾液沉淀物和口腔链球菌吸收培养基中的生物素或与白色念珠菌共同培养,显著抑制白色念珠菌的生长。本文首次提供实验证据显示口腔优势菌可能通过竞争生物素等营养成份,抑制白色念珠菌生长,以维持口腔微生物之生态平衡。     

铍对口腔链球菌生长及粘附性能的影响

目的 研究铍离子(Be2+)对口腔链球菌的生长及粘附性能的影响,探讨口腔修复治疗后牙周损伤的微生物机制.方法 含有不同浓度Be2+(5、10、20和40 mg/L)的培养液厌氧培养口腔链球菌24h.检测不同浓 度Be2作用后细菌形态和菌落形成单位(CFU),以及口腔链球菌在唾液包被羟基磷灰石微粒表面的粘附抑制率.结果 铍离子作用后口腔链球菌长链缩短,菌体出现集结趋势.20 mg/L时,菌体表面出现“触角样”变化.随Be2+浓度增加,CFU值减小(P＜0.05),口腔链球菌生长抑制.各实验组口腔链球菌粘附抑制率高于阳性对照组(P＜0.05),但各Be2+浓度组之间粘附抑制率差异无统计学意义(P＞0.05).结论 铍离子抑制口腔链球菌的生长和在牙面的粘附,可能会导致修复体周围正常微生态环境失衡,引起牙周疾病.提示临床应尽量选用理化性能稳定的修复材料.     

Comparison of adhesion of the food spoilage bacterium Shewanella putrefaciens to stainless steel and silver surfaces

AIMS: To compare the number of attached Shewanella putrefaciens on stainless steel with different silver surfaces, thus evaluating whether silver surfaces could contribute to a higher hygienic status in the food industry. METHODS AND RESULTS: Bacterial adhesion to three types of silver surface (new silver, tarnished silver and sulphide-treated silver) was compared with adhesion to stainless steel (AISI 316) using the Malthus indirect conductance method to estimate the number of cfu cm(-2). The number of attached bacteria on new silver surfaces was lower than on steel for samples taken after 24 h. However, this was not statistically significant (P > 0.05). The numbers of attached bacteria were consistently lower when tarnished silver surfaces were compared with stainless steel and some, but not all, experiments showed statistical significance (P < 0.05). Treating new silver with sulphide to reproduce a tarnished silver surface did not result in a similar lowering of adhering cells when compared with steel (P > 0.05). CONCLUSIONS: New or tarnished silver surfaces caused a slight reduction in numbers of attached bacteria; however, the difference was only sometimes statistically significant. SIGNIFICANCE AND IMPACT OF THE STUDY: The lack of reproducibility in differences in numbers adhering to the different surfaces and lack of statistical significance between numbers of adhered viable bacteria do not indicate that the tested silver surfaces can be used to improve hygienic characteristics of surfaces in the food industry.     

The Design of Simple Bacterial Microarrays: Development towards Immobilizing Single Living Bacteria on Predefined Micro-Sized Spots on Patterned Surfaces

In this paper we demonstrate a procedure for preparing bacterial arrays that is fast, easy, and applicable in a standard molecular biology laboratory. Microcontact printing is used to deposit chemicals promoting bacterial adherence in predefined positions on glass surfaces coated with polymers known for their resistance to bacterial adhesion. Highly ordered arrays of immobilized bacteria were obtained using microcontact printed islands of polydopamine (PD) on glass surfaces coated with the antiadhesive polymer polyethylene glycol (PEG). On such PEG-coated glass surfaces, bacteria were attached to 97 to 100% of the PD islands, 21 to 62% of which were occupied by a single bacterium. A viability test revealed that 99% of the bacteria were alive following immobilization onto patterned surfaces. Time series imaging of bacteria on such arrays revealed that the attached bacteria both divided and expressed green fluorescent protein, both of which indicates that this method of patterning of bacteria is a suitable method for single-cell analysis.     

Fluorescence-based bacterial overlay method for simultaneous in situ quantification of surface-attached bacteria

For quantification of bacterial adherence to biomaterial surfaces or to other surfaces prone to biofouling, there is a need for methods that allow a comparative analysis of small material specimens. A new method for quantification of surface-attached biotinylated bacteria was established by in situ detection with fluorescence-labeled avidin-D. This method was evaluated utilizing a silicon wafer model system to monitor the influences of surface wettability and roughness on bacterial adhesion. Furthermore, the effects of protein preadsorption from serum, saliva, human serum albumin, and fibronectin were investigated. Streptococcus gordonii, Streptococcus mitis, and Staphylococcus aureus were chosen as model organisms because of their differing adhesion properties and their clinical relevance. To verify the results obtained by this new technique, scanning electron microscopy and agar replica plating were employed. Oxidized and poly(ethylene glycol)-modified silicon wafers were found to be more resistant to bacterial adhesion than wafers coated with hydrocarbon and fluorocarbon moieties. Roughening of the chemically modified surfaces resulted in an overall increase in bacterial attachment. Preadsorption of proteins affected bacterial adherence but did not fully abolish the influence of the original surface chemistry. However, in certain instances, mostly with saliva or serum, masking of the underlying surface chemistry became evident. The new bacterial overlay method allowed a reliable quantification of surface-attached bacteria and could hence be employed for measuring bacterial adherence on material specimens in a variety of applications.     

Bacterial adhesion to hydroxyl- and methyl-terminated alkanethiol self-assembled monolayers.

The attachment of bacteria to solid surfaces is influenced by substratum chemistry, but to determine the mechanistic basis of this relationship, homogeneous, well-defined substrata are required. Self-assembled monolayers (SAMs) were constructed from alkanethiols to produce a range of substrata with different exposed functional groups, i.e., methyl and hydroxyl groups and a series of mixtures of the two. Percentages of hydroxyl groups in the SAMs and substratum wettability were measured by X-ray photoelectron spectroscopy and contact angles of water and hexadecane, respectively. SAMs exhibited various substratum compositions and wettabilities, ranging from hydrophilic, hydroxyl-terminated monolayers to hydrophobic, methyl-terminated monolayers. The kinetics of attachment of an estuarine bacterium to these surfaces in a laminar flow chamber were measured over periods of 120 min. The initial rate of net adhesion, the number of cells attached after 120 min, the percentage of attached cells that adsorbed or desorbed between successive measurements, and the residence times of attached cells were quantified by phase-contrast microscopy and digital image processing. The greatest numbers of attached cells occurred on hydrophobic surfaces, because (i) the initial rates of adhesion and the mean numbers of cells that attached after 120 min increased with the methyl content of the SAM and the contact angle of water and (ii) the percentage of cells that desorbed between successive measurements (ca. 2 min) decreased with increasing substratum hydrophobicity. With all surfaces, 60 to 80% of the cells that desorbed during the 120-min exposure period had residence times of less than 10 min, suggesting that establishment of firm adhesion occurred quickly on all of the test surfaces.     

Adhesion of biodegradative anaerobic bacteria to solid surfaces.

In order to exploit the ability of anaerobic bacteria to degrade certain contaminants for bioremediation of polluted subsurface environments, we need to understand the mechanisms by which such bacteria partition between aqueous and solid phases, as well as the environmental conditions that influence partitioning. We studied four strictly anaerobic bacteria, Desulfomonile tiedjei, Syntrophomonas wolfei, Syntrophobacter wolinii, and Desulfovibrio sp. strain G11, which theoretically together can constitute a tetrachloroethylene- and trichloroethylene-dechlorinating consortium. Adhesion of these organisms was evaluated by microscopic determination of the numbers of cells that attached to glass coverslips exposed to cell suspensions under anaerobic conditions. We studied the effects of the growth phase of the organisms on adhesion, as well as the influence of electrostatic and hydrophobic properties of the substratum. Results indicate that S. wolfei adheres in considerably higher numbers to glass surfaces than the other three organisms. Starvation greatly decreases adhesion of S. wolfei and Desulfovibrio sp. strain G11 but seems to have less of an effect on the adhesion of the other bacteria. The presence of Fe(3+) on the substratum, which would be electropositive, significantly increased the adhesion of S. wolfei, whereas the presence of silicon hydrophobic groups decreased the numbers of attached cells of all species. Measurements of transport of cells through hydrophobic-interaction and electrostatic-interaction columns indicated that all four species had negatively charged cell surfaces and that D. tiedjei and Desulfovibrio sp. strain G11 possessed some hydrophobic cell surface properties. These findings are an early step toward understanding the dynamic attachment of anaerobic bacteria in anoxic environments.     

Fluorescence-Based Bacterial Overlay Method for Simultaneous In Situ Quantification of Surface-Attached Bacteria

For quantification of bacterial adherence to biomaterial surfaces or to other surfaces prone to biofouling, there is a need for methods that allow a comparative analysis of small material specimens. A new method for quantification of surface-attached biotinylated bacteria was established by in situ detection with fluorescence-labeled avidin-D. This method was evaluated utilizing a silicon wafer model system to monitor the influences of surface wettability and roughness on bacterial adhesion. Furthermore, the effects of protein preadsorption from serum, saliva, human serum albumin, and fibronectin were investigated. Streptococcus gordonii, Streptococcus mitis, and Staphylococcus aureus were chosen as model organisms because of their differing adhesion properties and their clinical relevance. To verify the results obtained by this new technique, scanning electron microscopy and agar replica plating were employed. Oxidized and poly(ethylene glycol)-modified silicon wafers were found to be more resistant to bacterial adhesion than wafers coated with hydrocarbon and fluorocarbon moieties. Roughening of the chemically modified surfaces resulted in an overall increase in bacterial attachment. Preadsorption of proteins affected bacterial adherence but did not fully abolish the influence of the original surface chemistry. However, in certain instances, mostly with saliva or serum, masking of the underlying surface chemistry became evident. The new bacterial overlay method allowed a reliable quantification of surface-attached bacteria and could hence be employed for measuring bacterial adherence on material specimens in a variety of applications.     

Immunohistochemistry on Resin Sections: A Comparison of Resin Embedding Techniques for Small Mucosal Biopsies

We have modified resin embedding methods to provide optimal information from en-doscopic biopsies. Mucosal biopsies were fixed either in buffered formalin and processed for embedding in Araldite or in acetone containing protease inhibitors and embedded in glycol meth-acrylate (GMA). GMA embedding generated an im-munophenotypic profile similar to that obtained in frozen sections while yielding far superior morphology and greater numbers of sections from small biopsies. The phenotypic markers included those for T cells, macrophages, mast cells, eosin-ophils and neutrophils. We have also demonstrated collagens, cell adhesion molecules and integrin molecules. Sections of similar quality were obtained with Araldite but the repertoire of antibodies was restricted to those which can be applied to formalin fixed, paraffin embedded tissues. We suggest that for optimal results, small biopsies to be subjected to immunochemistry are fixed in acetone at -20 C with the inclusion of protease inhibitors and embedded in GUIA with careful temperature control.     

Enzyme-Linked Immunofiltration Assay To Estimate Attachment of Thiobacilli to Pyrite

An enzyme-linked immunofiltration assay (ELIFA) has been developed in order to estimate directly and specifically Thiobacillus ferrooxidans attachment on sulfide minerals. This method derives from the enzyme-linked immunosorbent assay but is performed on filtration membranes which allow the retention of mineral particles for a subsequent immunoenzymatic reaction in microtiter plates. The polyclonal antiserum used in this study was raised against T. ferrooxidans DSM 583 and recognized cell surface antigens present on bacteria belonging to the genus Thiobacillus. This antiserum and the ELIFA allowed the direct quantification of attached bacteria with high sensitivity (10⁴ bacteria were detected per well of the microtiter plate). The mean value of bacterial attachment has been estimated to be about 10⁵ bacteria mg⁻¹ of pyrite at a particle size of 56 to 65 μm. The geometric coverage ratio of pyrite by T. ferrooxidans ranged from 0.25 to 2.25%. This suggests an attachment of T. ferrooxidans on the pyrite surface to well-defined limited sites with specific electrochemical or surface properties. ELIFA was shown to be compatible with the measurement of variable levels of adhesion. Therefore, this method may be used to establish adhesion isotherms of T. ferrooxidans on various sulfide minerals exhibiting different physicochemical properties in order to understand the mechanisms of bacterial interaction with mineral surfaces.     

Embrace树脂和LuxaCoreZ-Dual树脂在纤维桩全冠修复牙冠严重缺损的效果对比

目的:比较Embrace树脂和Luxa Core Z-Dual树脂在纤维桩全冠修复牙冠严重缺损的效果。方法:将116颗牙冠严重缺损的患牙行根管治疗后随机分为两组,A组60颗(前牙39颗,后牙21颗)采用Embrace树脂及纤维桩全冠修复。B组56颗(前牙33颗,后牙23颗)采用Luxa Core Z-Dual树脂及纤维全冠修复,比较两组患牙的修复效果。结果:对所有患者随访3-12月,A组58颗牙修复体完好,失败2颗,成功率为96.66%,其中前牙失败2颗,成功率为94.87%,而后牙成功率为100%;B组54颗牙修复体完好,2颗失败,成功率为96.43%,其中前牙失败2颗,成功率为93.94%,而后牙成功率为100%,两组患牙修复体成功率比较差异无统计学意义(P0.05),4颗修复体的失败均因纤维桩松动脱落所致。结论:Embrace树脂和Luxa Core Z-Dual树脂在纤维桩全冠修复牙冠严重缺损时均具有良好的临床疗效,但Embrace树脂临床操作上更简便。