类M蛋白对HEp-2细胞的黏附作用

采用通用的模式细胞HEp 2作黏附及黏附抑制试验 ,研究马链球菌兽疫亚种ATCC35 2 4 6株类M蛋白的黏附作用。结果表明 ,ATCC35 2 4 6株可以黏附HEp 2细胞。用重组表达的类M蛋白鼠抗血清处理ATCC35 2 4 6 ,可抑制其对HEp 2细胞的黏附 ,最大抑制率达 81 4 % ;而ATCC35 2 4 6的全菌鼠抗血清在 1∶80 0时能完全抑制它对HEp 2细胞的黏附。此外 ,热酸提取的ATCC35 2 4 6株的类M蛋白和重组表达的类M蛋白可不同程度地抑制该菌株的黏附 ,前者在 16 0μg·mL-1有最大的黏附抑制率 ( 4 0 % ) ,而后者在 6 0 μg·mL-1的黏附抑制率可达最高值 ( 2 3% )。结果显示 ,类M蛋白是ATCC35 2 4 6株的黏附素之一 ,在对细胞的黏附过程中发挥作用     

农用柴油机气缸套磨损与对策

本文从农机运用的观点对农用柴油机、拖拉机气缸套内壁磨损的原因、特征及预防措施进行了系统的分析研究。结果表明,气缸套内壁磨损形式主要分为磨粒磨损、粘着磨损、腐蚀磨损及综合磨损,不同的磨损形式其磨损特征及预防措施亦不相同。当发动机某一使用工况下工作时,某种磨损形式(或几种磨损形式)会起主导作用,其外观形貌特征相应地表现为它的磨损特征,这就为正确判断分析发动机气缸套内壁磨损的原因及采取正确的预防措施提供了科学依据。     

The expression of NF-κB and ICAM-1 in rat brain of experimental intracerebral hemorrhage and cerebral microvascular endothelial cells injured by hydrogen peroxide

AIM: To discuss the possible mechanism of the inflammation after intracerebral hemorrhage (ICH) and the relationship of nuclear factor-kappa B (NF-κB) and intercellular adhesion molecule-1 (ICAM-1). METHODS: The expression of NF-κB and ICAM-1 were detected by immunohistochemistry, in situ hybridization, immunocytochemistry and Western blotting techniques in rat brain of experimental ICH and cerebral microvascular endothelial cells (RCMECs) injured by hydrogen peroxide. RESULTS: The expression of NF-κB p65 and ICAM-1 were up-regulated in rat brain after ICH. The ICAM-1 reached the peak at 1 day while the NF-κB at 4th day. NF-κB p65 expressed remarkably in cultured RCMECs immediately after injured by hydrogen peroxide, while ICAM-1 expressed remarkably　2 hours later. PDTC, an inhibitor of NF-κB, down-regulated the expression of NF-κB and ICAM-1. CONCLUSION: NF-κB induces the expression of ICAM-1 in RCMECs injured by reactive oxygen species (ROS).     

Cell adhesion molecules, leukocyte trafficking, and strategies to reduce leukocyte infiltration

Leukocyte-endothelial cell interactions are mediated by various cell adhesion molecules. These interactions are important for leukocyte extravasation and trafficking in all domestic animal species. An initial slowing of leukocytes on the vascular endothelium is mediated by selectins. This event is followed by (1) activation of beta2 integrins after leukocyte exposure to cytokines and pro-inflammatory mediators, (2) adherence of leukocyte beta2 integrins to vascular endothelial ligands (eg, intercellular adhesion molecule-1 [ICAM-1]), (3) extravasation of leukocytes into tissues through tight junctions of endothelial cells mediated by platelet and endothelial cell adhesion molecule-1 (PECAM-1), and (4) perivascular migration through the extracellular matrix via beta1 integrins. Inhibiting excessive leukocyte egress and subsequent free radical-mediated damage caused by leukocyte components may attenuate or eliminate tissue damage. Several methods have been used to modify leukocyte infiltration in various animal models. These methods include nonspecific inhibition of pro-inflammatory mediators and adhesion molecules by nonsteroidal anti-inflammatory drugs (NSAIDs) and glucocorticoids, inhibition of cytokines and cytokine receptors, and inhibition of specific types of cell adhesion molecules, with inhibitors such as peptides and antibodies to beta2 integrins, and inhibitors of selectins, ICAMs, and vascular cell adhesion molecule-1 (VCAM-1). By understanding the cellular and molecular events in leukocyte-endothelial cell interactions, therapeutic strategies are being developed in several animal models and diseases in domestic animal species. Such therapies may have clinical benefit in the future to overcome tissue damage induced by excessive leukocyte infiltration.     

Quantification of Staphylococcus aureus adhesion to equine bone surfaces passivated with Plasmalyte and hyperimmune plasma

OBJECTIVE: To quantify the adhesion of Staphylococcus aureus to 4 equine bone surfaces passivated in a balanced polyionic solution (Plasmalyte) or hyperimmune equine plasma (Polymune plasma). STUDY DESIGN: In vitro comparative study. SAMPLE POPULATION: Third metacarpal bone (MC3) surface explants from 9 equine cadavers. METHODS: Approximately 1 cm(2) sections of periosteum were removed from MC3 and stapled to sterile stainless steel screens. Three bone surface explants were cut using a surgical saw to present 1 cm(2) surfaces of subperiosteal bone, cut cortical bone, or endosteum. Duplicate explants of each surface were immersed for 1 hour in Plasmalyte or hyperimmune equine plasma. Each explant was then placed in a well of a 6-well sterile tissue culture plate with the surface of interest exposed. Each surface was inoculated with approximately 100 colony-forming units of S. aureus in 10 microL of Mueller Hinton broth and incubated for 6 hours at 37 degrees C. After gentle rinsing to remove non-adherent bacteria, samples were sonicated for 5 minutes at 60 kHz to loosen adhered bacteria. The number of adherent bacteria was determined by serial dilutions and incubation of the sonicate. Scanning electron microscopy (SEM) was performed on samples identically treated from an additional horse to confirm bacterial removal by sonication from all surfaces and support quantitative culture results. RESULTS: Less S. aureus adhered to periosteum than to cortical bone, cut cortical bone, and endosteal surfaces, which were all similar. Exposure of all surfaces to hyperimmune plasma reduced S. aureus adherence compared with Plasmalyte exposure; SEM supported these conclusions. CONCLUSION: Less bacteria adhere to periosteum than other bone surfaces. Hyperimmune plasma reduces bacterial adhesion to all bone tissue surfaces. CLINICAL RELEVANCE: Understanding the factors that affect bacterial adhesion to bone will facilitate development of improved intraoperative lavage solutions to reduce the morbidity and mortality associated with postoperative infection.     

清髓愈疽丹对血栓闭塞性脉管炎模型大鼠血栓相关因子的影响

通过人工建立血栓闭塞性脉管炎大鼠模型，结合病理学切片结果，利用荧光定量PCR和ELISA方法检测病变组织中的Icam-1、Vcam-1和血清中的血栓素B2（TXB2）、抗内皮细胞抗体（AECA）的含量。结果表明清髓愈疽丹能够通过有效地降低Icam-1、Vcam—1、TXB2、AECA的含量，抑制淋巴细胞、白细胞的浸润和血小板的黏附聚集，阻止血液高凝状态的形成；延缓损伤内皮处免疫复合物的形成，从而减轻痛变部位的炎症与损伤，因此能抑制血栓的形成，对TAO有确实的疗效。     

仿生学在农机减阻中的应用

在农业机械化的推广过程中,阻力过大是制约其发展的重要因素,而仿生学提出了解决此问题的新思路。详细介绍非光滑表面脱附减阻、减粘降阻的机理,及其在农机减阻方面的应用现状,为仿生学在农机设计中的应用提供参考。     

选择素及其在胚胎附植中的作用

选择素是已知的细胞黏附分子(CAMs)家族之一,共有3个成员组成,其主要生理功能是在炎症发生时介导白细胞与血管内皮细胞之间的起始黏附。近年来研究资料显示,选择素还在受精、肿瘤细胞转移和胚胎附植等过程中发挥着重要的作用,其中滋养层L-选择素介导胚泡滋养层与子宫之间的相互作用,在胚胎附植时发挥桥梁作用。     

Effect of decorin and selected glycosylation inhibitors on the adhesion of caruncular epithelial cells of pregnant cows—part I

Adhesion process ensures the formation of the appropriate connection between mother and foetus during placentation and further placental development, which determines physiological pregnancy course. Extracellular matrix of foetal membranes are a rich source of biologically active proteins, the synthesis of which is regulated by hormones. Depending on the stage of pregnancy, the protein profile of the placenta changes, thanks to which its remodelling is possible. The aim of the study was to evaluate the effect of decorin, as well as selected glycosylation inhibitors on the adhesion of caruncular epithelial cells derived from cows during pregnancy. Placental cells were isolated from healthy, pregnant (2nd and 4th month) cows after slaughter, which allowed for the establishment of 4 primary cell cultures without visible cells of fibroblast morphology. The presence of decorin in cell monolayer and cell lysates was determined by the use of immunocytochemistry and Western blotting, respectively. The viability of cells was evaluated by MTT assay. The adhesion of cells to fibronectin was measured spectrophotometrically. Protein N-glycosylation and O-glycosylation have a modulating effect on the adhesion and viability of placental cells during early–mid pregnancy. Decorin and tunicamycin were shown to have anti-adhesive properties with respect to caruncular cells of the pregnant bovine uterus.