Cytotoxicity Test of One-Step Self-Etching Bonding Agents by Standardized Dentin Barrier Test Using Polyurethane Discs

This study was performed to standardize a dentin barrier test with the substitute and evaluate the cytotoxicity of one-step self-etching bonding agents. Each of the natural bovine dentin and polyurethane discs were 500-μm thick and were tested using a perfusion device. Following the treatment with 0.05% phenol on the natural bovine disc or three kinds of polyurethane discs—30, 40, and 50 pcf (pounds per cubic foot)—cell viability of L-929 was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and expressed as percentages of non-treated group, respectively. A substitute showing permeability similar to that of bovine dentin was determined based on this result. Cytotoxicity test of bonding agents was performed by the selected substitute, the results of which were expressed as percentages of the control. In addition, SEM images were taken after the tests. The cell viability by 40-pcf polyurethane disc was not statistically different from that by bovine dentin disc (P > 0.05). Futurabond DC resulted in the highest cell viability and Bond force the lowest by the 40-pcf polyurethane disc (P < 0.05). The adhesives on the 40-pcf polyurethane disc changed cellular morphology with different degrees on the SEM images. This standardized test might be useful for assessing the cytotoxicity of dental materials applied to dentin before clinical applications.     

肉芽组织中NK1受体表达与创面愈合关系的实验研究

目的：研究创面愈合过程中NK1受体（NK1R）在肉芽组织成纤维细胞上的表达及其与创面愈合之间的关系。方法：新生Sprague-Dawley仔鼠20只，随机分为两组，每组10只。其中一组注射辣椒素将皮肤内感觉神经纤维破坏，制成“失感觉神经支配模型“，另一组作对照。两组动物均在腹部制作圆形皮肤缺损，并各选5只分别在一定时间点沿创面周缘及底部取材，进行NK1受体的免疫组织荧光染色及HE染色，观察其相应的时间、空间规律；另外5只不取材，而是在一定时间点测量未愈合的残留创面面积，并进行比较。结果：创面愈合过程中正常大鼠与去感觉神经支配大鼠在肉芽组织成纤维细胞均有NK1R表达；损伤后NK1R表达阳性的成纤维细胞形态变肥厚，胞体增大，车增殖旺盛表现；NK1R在感觉神经支配的大鼠成纤维细胞上的表达较正常对照升高；去感觉神经的大鼠与正常大鼠相比，创面愈合速度较慢。结论：大鼠皮肤NK1R表达与创面愈合之间关系密切，由感觉神经末梢所释放的P物质等神经递质可能是调节促进创面愈合的重要因子之一。     

Collagen type IV and procollagen type III during granulation tissue formation: a serological, biochemical, immunohistochemical and morphometrical study on the viscose cellulose sponge rat model

The serum concentrations of collagen type IV,7S, collagen type IV,nc1, and aminoterminal type III procollagen peptide immunoreactive components were measured by means of specific radioimmunoassays during development of granulation tissue in rats. The results were compared with tissue deposition of basement membranes and interstitial collagens in the granulation as measured morphometrically. A parallel sequential pattern in tissue deposition of collagen types III and IV, and serum increase of collagen types III- and IV-related fragments, was observed. Serum collagen type IV was less sensitive as a marker for development of granulation tissue than the serum procollagen type III N-peptide. This was in accordance with a low collagen type IV/interstitial collagen ratio in the granulation tissue. However, a cross-sectional study showed that serum collagens types IV,7S and IV,nc1 may be useful as early quantitative indicators of granulation tissue formation. Simultaneously, measurement of collagen type IV- and procollagen type III N-peptide-related antigens in serum provides a differentiated reflection of the dynamic matrix processes in developing granulation tissue.     

A simple,single-step technique for selecting and cloning hybridomas for the production of monoclonal antibodies

A simple method is described by which hybridomas can be selected and cloned in a single step immediately after fusion. This is done by plating the cells in semi-solid medium containing methylcellulose and the components of the HAT selection system. A number of variables have been examined in order to optimise the technique. The system is particularly suitable for isolating large numbers of hybridomas secreting different monoclonal antibodies. Evidence is presented to show that the colonies which grow in the system are in all probability clones. Thus, the need for routine recloning of the hybridomas is eliminated. In this way, the technique cuts down on the amount of tissue culture work associated with the production of monoclonal antibodies. Using this technique, it is easier to plate out large numbers of cells and to recover many independent hybridoma clones, than is the case when using cloning by limiting dilution.     

创伤愈合中表皮再生机理的研究──Ⅰ人创面肉芽的光镜电镜观察

本文从患者创面切取健康肉芽及不良肉芽（水肿性及弛缓性），观察其显微及超微结构。实验结果表明水肿性及弛缓性肉芽的成纤维细胞变性、坏死、新生毛细血管发育不良．这可能是影响表皮再生的重要因素。     

创伤愈合中表皮再生机理的研究──Ⅲ不同肉芽各种氨基酸含量的测定

上皮组织的生长，与创面肉芽组织状况有关。当肉芽与创周皮缘持平时（正常）上皮生长快，高于（高凸型）或低于（凹陷型）创缘时上皮生长受阻。本文检测了三种类型肉芽的各种氨基酸含量，发现高凸型及凹陷型肉芽中甘氨酸、丙氨酸、脯氨酸明显低于正常肉芽，是否影响着上皮生长，尚待进一步研究。     

Wound healing: the role of gap junctional communication in rat granulation tissue maturation.

Granulation tissue maturation is dependent upon the orientation of collagen fibers and cell differentiation. Gap junctions are intercellular membrane gated channels that facilitate direct communication between cells known as gap junctional intercellular communication (GJIC). The hypothesis is that GJIC modulates the maturation of granulation tissue during wound repair. In vitro, GJIC optimizes fibroblast-populated collagen lattice contraction and influences cell morphology. It is reported that LiCl increases GJIC in cultured cardiac myocytes. Polyvinyl alcohol (PVA) sponge implants with central reservoirs were placed within separate subcutaneous pockets on the backs of adult male Sprague-Dawley rats. Each PVA implant received either 20 mM LiCl or saline injections on days 5, 7, and 10 after implantation. On day 11 implants were harvested and processed for light microscopy. By H&E staining LiCl-treated implants showed increased vascularization and decreased cell density compared to saline controls. Polarized light microscopy of Sirius red-stained specimens revealed more intense collagen fiber birefringence secondary to dense, parallel-organized collagen fiber bundles after LiCl treatment. This suggests that LiCl enhancement of GJIC between fibroblasts advances the maturation of granulation tissue. It is proposed that the degree of GJIC between granulation tissue fibroblasts influences both the quantity and the quality of granulation tissue deposited during the wound healing process.     

一步法制粒器的应用

介绍了可完成混和、成粒及干燥各工序的、以流动床为主体的一步制粒器。说明了其原理、防爆措施及应用实例。     

重组人碱性成纤维细胞生长因子对大、小鼠胃溃疡的影响

目的:研究重组人碱性成纤维细胞生长因子(rh-bFGF)对实验性溃疡病的治疗作用。方法:采用大鼠和小鼠溃疡病模型,用图象分析仪进行形态计量,用显微镜观察病理组织学变化,用二苯胺法测DNA含量,用地衣酚法测RNA含量。结果:对大鼠醋酸性溃疡,rh-bFGF 2.5-40kU·kg~(-1)igbid缩小溃疡指数;最佳剂量为10kU·kg~(-1);量-效曲线呈钟型。rh-bFGF使溃疡边缘再生腺上皮宽度、肉芽组织内毛细血管密度及瘢痕组织内胶原含量提高;并促进再生腺体成熟与溃疡边缘组织RNA合成。对急性溃疡模型,rh-bFGF 5,10kU·kg~(-1)仅对大鼠幽门结扎型有效,但不影响胃液酸度及胃蛋白酶活性。结论:rh-bFGF ig或sc加速大鼠慢性胃溃疡愈合,并提高愈合质量。