Effect of totally absorbable implant volume on wound infection rate: Study of 2500 operated fractures, osteotomies, and ligament injuries

Between November 1984 and January 1994 in our department, a total of 2500 patients were treated with totally absorbable internal fixation devices. We studied these patients and analyzed results with regard to the volume of the absorbable implants and the development of wound infection. Of the 2500 patients 2044 were trauma patients and 456 were operated on for orthopedic disease. In 1466 patients treated with implants made of self-reinforced polyglycolic acid (SR-PGA) only, the patients who developed wound infection had a higher implant volume (P=0.07) than those who did not; this difference was close to statistical significance. In the 446 patients who received only implants made of self-reinforced poly-l-lactic acid (SR-PLLA), the 5 who developed wound infection had a mean implant volume more than three times that of the non-infected patients (P=0.01). We found that in the patients treated with the earlier SR-PGA implants, which contained a green staining material, there was no correlation between implant volume and incidence of wound infections. On the other hand, both the non-stained SR-PGA implants, which have been in clinical use since 1989, and the SR-PLLA implants, seem to be more predictable in terms of wound infections. We believe that this difference, is largely due to the lower level of tissue reactions with these newer implants.     

异种脱细胞角膜基质囊袋移植的生物相容性研究

目的探讨脱细胞猪角膜基质移植入兔角膜囊袋后的生物学反应。方法猪角膜通过不同方式去除细胞及免疫源性成分，保留角膜组织基质的弹力纤维及胶原纤维，将其切取为直径为4mm的植片，植入兔角膜囊袋内，在不同时间点观察生物材料在角膜内生物学反应。结果材料植入兔角膜囊袋3个月，生物相容性良好，材料逐渐降解，材料内有胶原和角膜基质细胞长人。结论新型可降解角膜基质材料植入后未见兔角膜有明显的炎症反应，材料的组织相容性好，可作为组织工程角膜的支架材料。     

再生柞蚕丝素蛋白对人骨髓间充质干细胞体外扩增的支持作用

大量的研究表明家蚕丝素蛋白具有良好的生物相容性。而对于柞蚕丝素蛋白在医用生物领域的研究报道在国内外尚较少。本研究选择再生柞蚕丝素蛋白为研究对象，观察了人骨髓间充质干细胞（hBMSCs）在再生柞蚕丝素膜上的粘附、生长及表面抗原的变化。结果在1h观察再生柞蚕丝素对hBMSCs的粘附力几乎与胶原相同，明显优于家蚕丝素和聚苯乙烯培养板。MTT法检测结果显示在第4d hBMSCs在再生柞蚕丝素膜上的增殖明显高于其他各组。电镜观察结果显示hBMSCs在再生柞蚕丝素膜上能够很好的粘附、生长，细胞间能相互连接形成片状结构。流式细胞仪检测再生柞蚕丝素蛋白对hBMSCs表面抗原的表达亦无明显影响。本研究结果显示再生柞蚕丝素蛋白体外支持hBMSCs的粘附、生长，具有良好的细胞相容性。     

Modulation of Staphylococcus aureus adhesion by biofunctional copolymers derived from polystyrene

Biomaterials-centered infections are serious complications associated with the use of implants. The infection risk of biomaterials varies between different materials and is determined by the chemical composition of materials, the host proteins and the type of bacteria. In this study we measured the initial adhesion of Staphylococcus aureus onto polystyrene derivatives containing carboxylate and sulfonate groups. Five polymers were synthesized and characterized. We studied the role of the host protein fibronectin in promoting adhesion of Staphylococcus aureus. Fibronectin adsorption was comparable on all the tested polymers (pKd=7.2±0.2) whereas bacterial adhesion was dependent on surfaces chemical compositions. Polymers substituted with sulfonate groups showed the most important inhibition of initial bacterial adhesion.     

Biological resurfacing of the knee: a review of surgical management

Lesions of the articular surfaces of the knee have been managed by various techniques over the last 50 years. Surgical management has involved: excising the damaged area, refashioning the underlying bone to produce a fibrous response, and introducing allograft, autograft and synthetic materials to encourage a repair matrix. The techniques and their pitfalls are reviewed and discussed, and suggestions made as to the direction of future studies for the repair of osteochondral lesions in the painful knee.     

组织工程韧带支架材料研究进展

韧带损伤发生几率很高,并且能够导致关节不稳以及其他组织损伤进一步恶化,但在临床上却没有韧带损伤修复的有效手段。组织工程为再生韧带组织提供了一个新的途径,而运用此方法选取合适的支架材料显得尤为重要。综述了组织工程韧带支架材料的主要研究成果,着重论述了在此领域潜力巨大的天然生物材料胶原和蚕丝。虽然目前的研究取得了较大的进步,但仅处在起步阶段,距离大规模的临床应用还很远。最后指出了此领域的最终目标以及未来研究趋势。     

Improvement to the Corrosion Resistance of Ti-Based Implants Using Hydrothermally Synthesized Nanostructured Anatase Coatings

The electrochemical behavior of polycrystalline TiO₂ anatase coatings prepared by a one-step hydrothermal synthesis on commercially pure (CP) Ti grade 2 and a Ti13Nb13Zr alloy for bone implants was investigated in Hank’s solution at 37.5 °C. The aim was to verify to what extent the in-situ-grown anatase improved the behavior of the substrate in comparison to the bare substrates. Tafel-plot extrapolations from the potentiodynamic curves revealed a substantial improvement in the corrosion potentials for the anatase coatings. Moreover, the coatings grown on titanium also exhibited lower corrosion-current densities, indicating a longer survival of the implant. The results were explained by considering the effects of crystal morphology, coating thickness and porosity. Evidence for the existing porosity was obtained from corrosion and nano-indentation tests. The overall results indicated that the hydrothermally prepared anatase coatings, with the appropriate morphology and surface properties, have attractive prospects for use in medical devices, since better corrosion protection of the implant can be expected.     

The activation of human plasma prekallikrein as a hemocompatibility test for biomaterials. II. Contact activation by EVAL and EVAL-SMA copolymers

The activation of human plasma prekallikrein (PKK) to kallikrein (KK), induced by the contact of blood with foreign materials, is a useful in vitro hemocompatibility test. Kallikrein is easily detected by its reaction with the chromogenic substrate H-D-Pro-Phe-Arg-pNA, which releases p-nitroaniline, revealed by its absorption at 405 nm. This test, which was already carried out by evaluating PKK activation by the 'end-point' method, has been carried out in this work by the more accurate 'initial velocity' method, i.e. by evaluating the activation from the initial rates of the KK-substrate reaction. The tests were carried out on the following materials: borosilicate glass (as a high-activation reference material), silicone (as a low-activation reference material), the commercial biomaterial Cardiothane 51, three graft copolymers synthesized in our laboratory by reacting ethylene-vinyl alcohol copolymer (EVAL) with styrene-maleic anhydride copolymer (SMA), and EVAL itself. A mathematical treatment based on a simple kinetic model has been used for a first-approximation evaluation of the PKK-activating power of the materials tested. The quite low activating power of the EVAL-SMA copolymers, which are easily processable into water-permeable hollow fibers, suggests the possibility of their use in blood dialyzers.