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. 相似文献
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. 相似文献
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.
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. 相似文献