Lymphocyte Responses to Chemokines

Today, almost three dozen human chemokines have been identified. The main function of these soluble proteins is the recruitment of leukocytes to sites of infection and inflammation. This review emphasizes the new developments in the field of lymphocyte responses to chemokines. Notably, it was shown that lymphocytes require stimulation to become responsive to chemokines, a process that is closely linked to chemokine receptor expression. As an exception, one chemokine, SDF-1, is a highly effective chemoattractant for non-activated T lymphocytes and progenitor B cells. Of particular interest are the chemokines IP10 and Mlg which bind to a receptor with selective expression in activated T lymphocytes and, therefore, may be critical mediators of T lymphocyte migration in T cell-dependent immune-responses. All other chemokines with activities in lymphocytes do also induce responses in monocytes and granulocytes. The involvement of chemokine receptors in HIV infection is briefly mentioned, while other interesting areas in chemokine research, such as hematopoiesis and angiogenesis, are not discussed.     

Biofilm and cell adhesion strength on dental implant surfaces via the laser spallation technique

ObjectiveThe aims of this study are to quantify the adhesion strength differential between an oral bacterial biofilm and an osteoblast-like cell monolayer to a dental implant-simulant surface and develop a metric that quantifies the biocompatible effect of implant surfaces on bacterial and cell adhesion.MethodsHigh-amplitude short-duration stress waves generated by laser pulse absorption are used to spall bacteria and cells from titanium substrates. By carefully controlling laser fluence and calibration of laser fluence with applied stress, the adhesion difference between Streptococcus mutans biofilms and MG 63 osteoblast-like cell monolayers on smooth and rough titanium substrates is obtained. The ratio of cell adhesion strength to biofilm adhesion strength (i.e., Adhesion Index) is determined as a nondimensionalized parameter for biocompatibility assessment.ResultsAdhesion strength of 143 MPa, with a 95% C.I. (114, 176), is measured for MG 63 cells on smooth titanium and 292 MPa, with a 95% C.I. (267, 306), on roughened titanium. Adhesion strength for S. mutans on smooth titanium is 320 MPa, with a 95% C.I. (304, 333), and remained relatively constant at 332 MPa, with a 95% C.I. (324, 343), on roughened titanium. The calculated Adhesion Index for smooth titanium is 0.451, with a 95% C.I. (0.267, 0.622), which increased to 0.876, with a 95% C.I. (0.780, 0.932), on roughened titanium.SignificanceThe laser spallation technique provides a platform to examine the tradeoffs of adhesion modulators on both biofilm and cell adhesion. This tradeoff is characterized by the Adhesion Index, which is proposed to aid biocompatibility screening and could help improve implantation outcomes. The Adhesion Index is implemented to determine surface factors that promote favorable adhesion of cells greater than biofilms. Here, an Adhesion Index ? 1 suggests favorable biocompatibility.     

Current perspectives on dental adhesion: (3) Adhesion to intraradicular dentin: Concepts and applications

Adhesion science is one of the greatest contributions to restorative dentistry. Adhesion not only established the current principles of tissue preservation, but also allowed for the production of more hermetic and long-lasting restorations. Although adhesive strategies are routinely used in most clinical situations, adhesion to root dentin is still a major challenge. The presence of humidity together with less intertubular dentin are factors that limit the adhesive potential of root dentin. This situation is more unfavorable in endodontically treated teeth prepared for prefabricated or custom-made intraradicular posts; these procedures may alter the mechanical properties of teeth by modifying the viable dentin surface for adhesion. Also, contaminants deposited on the dentin surface are difficult to remove through conventional techniques. Moreover, root canal morphology has a very unfavorable C-factor, bringing undesirable effects resulting from polymerization contraction of resin-based materials. However, the differences between coronal and root dentin are not a barrier for dentin adhesion. Standardization of procedures and care during clinical steps are fundamental to the success of adhesion to coronal or intraradicular dentin. Thus, it is essential to know the anatomy of the root structure, the factors that interfere with intraradicular adhesion, as well as the current adhesive materials and techniques.     

Atraumatic Pulsatile Leukocyte Circulation for Long‐Term In Vitro Dynamic Culture and Adhesion Assays

Low flow rate pumping of cell suspensions finds current applications in bioreactors for short‐term dynamic cell culture and adhesion assays. The aim of this study was to develop an atraumatic pump and hemodynamically adapted test circuit to allow operating periods of at least several hours. A computer‐controlled mini‐pump (MP) was constructed based on non‐occlusive local compression of an elastic tube with commercial bi‐leaflet valves directing the pulsatile flow into a compliant circuit. Cell damage and activation in the system were tested with whole blood in comparison with a set with a conventional peristaltic pump (PP). Activation of circulating THP‐1 monocytes was tested by measuring the expression of CD54 (ICAM‐1). Additionally, monocyte‐endothelial interactions were monitored using a parallel‐plate flow chamber with an artificial stenosis. The system required a priming volume of only 20 mL, delivering a peak pulsatile flow of up to 35 mL/min. After 8 h, blood hemolysis was significantly lower for MP with 11 ± 3 mg/dL compared with PP with 100 ± 16 mg/dL. CD142 (tissue factor) expression on blood monocytes was 50% lower for MP. With MP, THP‐1 cells could be pumped for extended periods (17 h), with no enhanced expression of CD54 permitting the long‐term co‐culture of THP‐1 with endothelial cells and the analysis of flow pattern effects on cell adhesion. A low‐damage assay setup was developed, which allows the pulsatile flow of THP‐1 cells and investigation of their interaction with other cells or surfaces for extended periods of time.     

异氟醚和七氟醚对肺癌根治术患者血清E-selectin、ICAM-1、MMP-2、MMP-9表达的影响

目的评价异氟醚和七氟醚吸入麻醉对肺癌根治术患者血清E-选择素(E-selectin)、内皮细胞间黏附分子(ICAM)-1、基质金属蛋白酶(MMP)-2、MMP-9浓度变化的影响。方法择期行肺癌根治术患者60例,年龄43~68岁,ASAⅠ或Ⅱ级。采用随机数字表法,将患者随机均分为两组:异氟醚(I组)和七氟醚组(S组)。两组患者气管插管后吸入1.7%~2.3%异氟醚或2.5%~3.4%七氟醚,维持I组异氟醚呼气末浓度为1.5~2.0 MAC、S组七氟醚呼气末浓度维持在1.5~2.0 MAC至术毕。于麻醉诱导前5min(T0)、手术开始后1h(T1)、手术开始后2h(T2)和术后1h(T3)时采集静脉血样,酶联免疫吸附法测定血清E-selectin、ICAM-1、MMP-2、MMP-9表达。结果与T0时比较,T1~T3时I组血清E-selectin、ICAM-1、MMP-2、MMP-9表达明显增加(P0.05),T2、T3时S组血清E-selectin、ICAM-1、MMP-2、MMP-9表达明显降低(P0.05)。T1~T3时S组血清E-selectin、ICAM-1、MMP-2、MMP-9表达明显低于I组(P0.05)。结论七氟醚能抑制肺癌根治术患者血清E-selectin、ICAM-1、MMP-2、MMP-9的表达。     

活化细胞黏附分子在甲状腺癌中的表达及其临床意义

目的:研究活化细胞黏附分子(ALCAM)在甲状腺癌组织中表达及其临床意义。方法:免疫组织化学法检测52例甲状腺癌组织及对应癌旁正常甲状腺组织中ALCAM的表达,比较ALCAM在两种组织中表达的差异,并分析其表达与甲状腺癌患者临床病理因素及预后的关系。结果:ALCAM在甲状腺癌组织中的阳性表达率明显高于癌旁正常甲状腺组织(71.2%vs.34.6%,P0.05),但在ALCAM在甲状腺癌组织中表达越低,甲状腺癌组织病理分化程度越低,患者5年总生存率越低(均P0.01)。结论:ALCAM表达增高可能参与甲状腺癌发生发展进程,然而,在恶性度高、预后差的甲状腺癌的肿瘤组织中ALCAM表达反而降低的原因推测可能与其脱落释放入血有关。     

E-selectin and very late activation antigen-4 mediate adhesion of hematopoietic progenitor cells to bone marrow endothelium

 Adhesion of CD34⁺ hematopoietic progenitor cells (HPCs) to sinusoidal endothelium probably plays a key role in homing of transplanted CD34⁺ HPCs to the bone marrow (BM). We have investigated the role of various adhesion molecules in the interaction of purified CD34⁺ HPCs derived from BM or peripheral blood (PB) and a human BM-derived endothelial cell line. Adhesion of CD34⁺ HPCs to endothelial cells was measured with the use of a double-color flow microfluorimetric adhesion assay. In this assay, adhesion is measured under stirring conditions, simulating blood flow in sinusoidal marrow vessels. Adhesion of PB CD34⁺ cells to human BM endothelial cells (HBMECs) was observed only after interleukin (IL)-1β prestimulation of the endothelial cells. This adhesion was strongly increased after addition of phorbol-myristate acetate (PMA). Adhesion of PB CD34⁺ cells to IL-1β-prestimulated HBMECs was inhibited by blocking monoclonal antibodies (mAbs) against E-selectin and by neuraminidase treatment of the PB CD34⁺ cells. mAbs against very late activation antigen (VLA)-4 inhibited adhesion only when the E-selectin-mediated interaction was prevented. No clear inhibiting effect was found with blocking mAbs against β₂-integrins. Stimulation with the β₁-integrin-activating mAb, 8A2, induced adhesion of CD34⁺ cells to endothelial cells. In conclusion, stimulation of both endothelial cells and CD34⁺ HPCs is necessary for adhesion of CD34⁺ HPCs to endothelial cells. We furthermore demonstrated that E-selectin and VLA-4 mediated this adhesion. Received: 26 April 1999 / Accepted: 8 February 2000     

透明质酸钠预防兔颞下颌关节开放术后粘连的实验研究

目的 比较不同分子量透明质酸钠预防兔颞下颌关节开放术术后关节粘连的效果,为预防颞下颌关节开放性手术术后粘连提供实验依据.方法 新西兰兔24只,行双侧颞下颌关节盘切除术,分3组分别植入不同材料,低分子透明质酸钠(A组),高分子透明质酸钠(B组),生理盐水对照(C组).在术后1周、2周、4周、8周处死动物,切取关节组织,进行大体标本和光镜观察,同时切取关节囊以及关节囊外侧的疤痕组织进行生化分析.结果 大体观察发现对照组关节囊外侧结缔组织较韧,形成明显的疤痕组织,较其它两组明显.低分子透明质酸钠和对照组出现明显纤维性粘连样改变,高分子透明质酸钠组无明显变化.高分子与低分子透明质酸钠组之间,以及高分子透明质酸钠组与对照组之间羟脯氨酸均有显著差异(P＜0.05).结论 高分子量透明质酸钠能减少髁突表面纤维结缔组织增生并降低关节囊组织的瘢痕化,减轻关节粘连.     

周期性拉伸应力与人永生化角质形成细胞的黏附和铺展

背景：皮肤组织所处的力学环境以及上皮细胞的铺展状态与伤口愈合和瘢痕形成过程关系密切。目的：分析胞外力学刺激对细胞铺展的作用,并检测细胞的增殖状态进一步分析铺展形态对细胞增殖等生理活动的影响。方法：通过FX-4000柔性基底加载系统对人永生化角质形成细胞(HaCaT)进行周期性拉伸应力正弦波加载,加载程式0.2 Hz,10%拉伸幅度。在0,24,48 h对细胞的铺展形态进行对比,利用流式细胞仪检测分析细胞的增殖,并利用免疫荧光染色方法对比分析纽蛋白在细胞内的分布。结果与结论：HaCaT细胞在加载24 h后分裂期细胞较多,铺展形态无明显变化;加载48 h后HaCaT细胞形态发生较为明显的变化,分裂期细胞较静态对照组略有减少;拉伸应力作用下纽蛋白的分布由细胞核周围的膜区域向细胞边缘集中。结果表明：适度的力学加载能够在保持细胞铺展和黏附状态下,促进细胞增殖;周期性持续拉伸应力的作用时间是HaCaT细胞铺展形态和与基底黏附位点的重要影响因素。     

槲皮素对人肝癌高转移细胞基质粘附能力的影响

目的 研究槲皮素对肝癌高转移细胞基质粘附能力的影响及其机制.方法 研究对象为人高转移肝细胞癌细胞HCCLM6,用细胞基质粘附实验检测槲皮素对细胞外基质粘附能力的影响,免疫荧光和Western blot 检测细胞内E-Cadherin蛋白表达.结果 槲皮素能抑制肝癌细胞对Marigel胶的粘附,免疫荧光和Western blot检测均发现槲皮素处理组肝癌细胞E-Cadherin蛋白表达较对照组增加(P＜0.05).结论 槲皮素能抑制肝癌高转移细胞的基质粘附能力,其机制之一可能在于槲皮素能上调肝癌细胞E-Cadherin蛋白表达.