Analysis of the biocompatibility of magnetic porous tricalcium phosphate ceramics in rat femurs

Summary A new biomaterial, magnetic porous tricalcium phosphate ceramics (MPTCP), may be used for repairing defects in bones as a substitute for bone grafting. This study was designed to examine its biocompatibility and the systemic toxicity. The ceramic sections, approximately 15.3 mg, were implanted into both proximal femurs of 10 male and 10 female albino SW rats. An equal number of male and female animals served as sham-operated controls. Implantation of MPTCP ceramics in rat femurs had no deleterious effects on body weight, organ/body weight ratio, and on blood, liver and kidney functions. Plasma levels of inorganic phosphorus were significantly elevated in rats implanted with MPTCP ceramics. Alkaline phosphatase values in plasma in the experimental group were equal to those in the control group. Photomicrographs, radiographs and scanning electron photomicrographs of the rat femurs implanted with MPTCP ceramics demonstrated excellent bone association with implants and growth of some new bone into MPTCP ceramics. In conclusion, MPTCP ceramics are biocompatible and suitable for the reconstruction of bones.     

A description of a prototype miniature extracorporeal membrane oxygenation circuit using current technologies in a sheep model

In the United States, standardization of neonatal extracorporeal membrane oxygenation (ECMO) circuit was achieved during the 1980s. Since that time, the consoles and components of the ECMO circuit have remained fundamentally unchanged (bladder, rollerpump, silicone membrane oxygenator). Extracorporeal technology, however, has witnessed many significant advancements in components during the past two decades. These new technologies have characteristics that may improve outcomes when applied in the ECMO arena. Understanding how these technologies perform in long-term applications is necessary. Therefore, the purpose of this project is to evaluate the performance of a miniature ECMO circuit consisting of current generation technologies in an animal model. An ECMO circuit (prime volume 145 mL) was designed that included a hollow fiber oxygenator and a remote mounted centrifugal pump. All circuit tubing and components were surface coated. Three sheep (approx 13 kg) were placed on ECMO using standard neck cannulation techniques and maintained according to clinical protocols. Technical implementation, oxygenator function, and hematological parameters were accessed. Duration of ECMO was 20, 48, and 58 hours. There was no evidence of oxygenator failure, as measured by pressure drop and oxygen transfer, in any of the procedures. No plasma leak was observed in any oxygenators. Platelet count trended downward after 24 hours. Visual inspection after ECMO showed very little evidence of gross thrombosis. This ECMO circuit design departs dramatically from the typical North American systems. The use of this console and components facilitated a 70% reduction in priming volume over a traditional ECMO circuit. Further investigations should be conducted to determine if circuit miniaturization can reduce the morbidity associated with blood product consumption and the bloods contact with the artificial surfaces of the ECMO circuitry.     

New Poly(oxyethylene) Derivatives from Diels–Alder Reactions of 3‐[Methoxypoly(oxyethylene)]methylene Furan

Summary: A new poly(ethylene glycol) derivative, 3‐[methoxypoly(oxyethylene)]methylene furan, I , was prepared from the reaction of 3‐furanmethanol with the mesylate of methoxypoly(oxyethylene) in tetrahydrofuran. The degree of end‐group conversion, as determined by NMR spectroscopy, was 100%. The Diels–Alder reactions of I with N‐phenylmaleimide, N‐glycinylmaleimide, maleic anhydride, N,N′‐hexamethylene bismaleimide, and diethyl acetylenedicarboxylate resulted in the corresponding adducts. For the adduct derived from I and N‐phenylmaleimide, its thermal reversible character was confirmed by applying a retro‐Diels–Alder reaction in the presence of a large excess of 2‐methylfuran, which restored the initial polymer I quantitatively. The adduct obtained from I and N‐glycinylmaleimide was converted into its succinimidyl ester and its hydrolysis rate in phosphate buffer (pH = 8) was determined. The reactivity of the adduct derived from I and N,N′‐hexamethylene bismaleimide with benzyl mercaptan was also investigated.

     

A comparative histological evaluation of the biocompatibility of materials used in apical surgery

AIM: To evaluate the biological properties of a variety of materials that could be used in apical surgery. METHODOLOGY: The intraosseous implant technique recommended by the FDI (1980) and ADA (1982) was used to test the following materials: zinc oxide-eugenol (ZOE), mineral trioxide aggregate (MTA), and Z-100 light-cured composite resin. Thirty guinea-pigs, 10 for each material, divided into experimental periods of 4 and 12 weeks, received one implant on each side of the lower jaw symphysis. The connective tissue response alongside the lateral wall outside the cup served as a negative control for the technique. At the end of the observation periods, the animals were killed and the specimens prepared for routine histological examination to evaluate their biocompatibility. RESULTS: The reaction of the tissue to the materials diminished with time. The ZOE cement was highly toxic during the 4-week experimental period, but this profile changed significantly after 12 weeks, when it showed biocompatible characteristics. MTA and Z-100 showed biocompatibility in this test model at both time periods. CONCLUSIONS: MTA and Z-100 composite were biocompatible at 4 and 12 weeks in this experimental model.     

TiO2纳米薄膜影响晶状体上皮细胞和巨噬细胞生长的体外研究

目的:观察经长波紫外线UVA(365nm)激发处理,TiO2纳米薄膜对体外培养的牛晶状体上皮细胞和小鼠腹腔巨噬细胞的抑制效应,研究该薄膜影响表面细胞生长的特性。方法:在玻片上涂覆TiO2纳米薄膜,并以未镀膜玻片为对照。将两种玻片在不同强度(0.102和0.825mW/cm2)的UVA下,照射0,10,20,30,40min,观察玻片表面的晶状体上皮细胞和巨噬细胞生长的数量和状态。实验用MTT比色法评估晶状体上皮细胞量,并以AO-EB染色法观察其形态;用瑞氏染色后计数法测定巨噬细胞量,并以扫描电镜观察其形态。结果:镀TiO2纳米薄膜玻片在0.102mW/cm2的UVA激发40min或0.825mW/cm2的UVA激发30min时,表面存活的细胞量比未镀膜玻片显著减少(P<0.01),且晶状体上皮细胞出现AO-EB染色的凋亡和坏死特征,巨噬细胞出现质膜破裂、细胞崩解的扫描电镜表现。激发时间越长,TiO2纳米薄膜上的细胞量越少,且0.825mW/cm2的光源较0.102mW/cm2的光源更能激发TiO2的杀伤作用。结论:TiO2纳米薄膜在UVA的激发照射后,能使其表面的晶状体上皮细胞和巨噬细胞发生凋亡或坏死。与照射时间呈时效关系。     

自制羟基磷灰石模拟体液中实验研究

目的：通过模拟体液实验研究观察自制羟基磷灰石的生物相容性。方法：选择接近人体环境的溶液，观察羟基磷灰石的表面变化、离子浓度、pH值变化情况。结论：自制羟基磷灰石具有很好的生物相容性。     

树脂根管充填材料ResilonTM

ResilonTM是一种新型根管充填材料,国外许多学者对其进行了多方面的研究。但由于研究方法及其使用的统计手段不一致,结果有所不同,褒贬也不一,因此其临床效能还有待进一步观察。     

碳质股骨头生物相容性的动物实验*★

背景：已有大量的临床和体外实验研究表明，低温热解各向同性碳具有优良的生物学性能，但作为人工关节假体涂层，置入髋关节内的研究还鲜见报道，其在人工半髋关节假体置换中的生物学性能还没有得到验证。 目的：通过动物假体置入实验，观察经低温热解各向同性碳(含硅)喷涂后碳质股骨头假体的组织相容性及表面摩擦磨损特性。 设计、时间及地点：动物体内进行碳质人工半髋关节替换，随机对照动物实验，于2008-10/2009-04在解放军第二军医大学动物实验中心完成。 材料：碳质人工半髋关节由吉林市中心医院提供。股骨头以碳石墨材料为基体，沉积含硅的低温热解各向同性碳为涂层。 方法：对16只成年新西兰大白兔进行右侧半髋关节置换术，置入碳质股骨头假体。按照观察时间点随机分为术后6周组4只，术后11周组6只，术后21周组6只，其中21周组从18周开始在动物实验中心草坪上进行诱导性运动，2 h/d。 主要观察指标：通过大体、X射线片、组织切片观察假体置入后的组织相容性及界面摩擦磨损现象。 结果：碳质股骨头假体在动物体内无毒副作用，无明显炎症反应和异物反应，在碳质假体周围发现有新生软骨组织，运动实验后碳质股骨头表面没有明显磨损和碳颗粒游离现象。 结论：涂膜碳质材料作为人工股骨头具有优良的生物相容性和耐磨特能，是一种极具应用前景的人工假体材料。 关键词：碳质股骨头；人工髋关节；生物相容性；新生软骨；磨损     

多糖生物膜的眼内生物相容性

目的 研究多糖生物膜（polysaccharide biomembrane,PSBM)在眼内的生物相容性，降解性。方法 将PSBM植片植入兔眼前房内，设对照组。术后观察眼压和PSBM植片形态变化；于植入后15，25，55d摘除眼球观察角膜内皮活性，晶状体上皮，虹膜局部及视网膜的形态变化；对晶状体上皮，视网膜的乳酸脱氢酶（LDH），琥珀酸脱氢酶（SDH），酸性磷酸酶（ACP），碱性磷酸酶（ALP）进行酶组织化学观察及统计学分析。结果 PSBM植片在眼内可完全降解吸收，角膜内皮活性，晶状体上皮，视网膜的组织学形态无显著变化，植入PSBM处的虹膜局部可见纤维增殖；各组实验眼与对照眼间的晶状体上皮和视网膜的LDH，SDH，ACP，ALP活性均无显著差异。结论 PSBM植入眼内可完全降解吸收，是有良好生物相容性的医用生物材料，有望在眼科得到开发应用。     

多孔磷酸三钙生物陶瓷和珊瑚的生物相容性比较研究

目的研究多孔磷酸三钙生物陶瓷和珊瑚在体外及体内生物相容性,为组织工程支架材料的选择提供实验依据。方法将兔MSCs分别与多孔磷酸三钙生物陶瓷和珊瑚体外复合,并经地塞米松、β-甘油磷酸钠、L-抗坏血酸诱导分化,然后植入新西兰大白兔的皮下。体外实验中进行形态学观察、细胞增殖、碱性磷酸酶测定;体内实验通过大体、组织学观察植入物的成骨情况。结果体外实验中MSCs在两组材料上均能贴壁生长,珊瑚材料组见少量细胞坏死,各组细胞数量均有所增加,体外培养第12d多孔磷酸三钙生物陶瓷组多于珊瑚组,差异有统计学意义;各组ALP值均明显升高,珊瑚组各时间点ALP值均高于多孔磷酸三钙生物陶瓷组,但差异无统计学意义。体内实验显示,多孔磷酸三钙生物陶瓷各时间观察点均可见骨组织生长和单核或多核巨细胞,无炎症细胞,12周材料已全部降解;珊瑚组各时间点可见骨组织、单核或多核巨细胞及少量炎症细胞生长,12周材料大部降解。结论体外和体内的实验表明,多孔磷酸三钙生物陶瓷和珊瑚均有较好的生物相容性,但前者较后者的相容性更好。