Electrospun microfiber meshes of silicon-doped vaterite/poly(lactic acid) hybrid for guided bone regeneration

Silicon-releasable microfiber meshes consisting of silicon-doped vaterite (SiV) particles and poly(lactic acid) (PLA) hybrids were prepared by electrospinning. Due to their flexibility and porosity they formed ideal membranes or scaffolds for guided bone regeneration. In addition, a trace amount of silicon species has been reported to stimulate osteogenic cells to mineralize and enhance bone formation. We propose a new method of preparation of silicon-releasing microfiber meshes by electrospinning. Their structure and hydroxyapatite (HA)-forming abilities in simulated body fluid were examined. In addition, we studied their stimulatory effects on osteoblast-like cells in vitro and bone-forming ability in vivo, with a special emphasis on their ability to release silicon. The meshes consisted of a hybrid of carboxy groups in PLA and amino groups in siloxane, derived from aminopropyltriethoxysilane or calcium ions on the SiV surface. This hybrid exhibited an enhanced ability to form HA. The meshes coated with HA released 0.2–0.7 mg l^?1 silicon species into the culture medium over 7 days. Enhanced proliferation of osteoblast-like cells was observed using the meshes and new bone formed on the meshes when implanted into the calvaria of rabbits. These meshes, therefore, provide an excellent substrate for bone regeneration and exhibit enhanced bone-forming ability under both in vitro and in vivo conditions.     

Molecular resurfacing of cartilage with proteoglycan 4

Early loss of proteoglycan 4 (PRG4), a lubricating glycoprotein implicated in boundary lubrication, from the cartilage surface has been associated with degeneration of cartilage and early onset of osteoarthritis. Viscosupplementation with hyaluronic acid and other macromolecules has been proposed as a treatment of osteoarthritis. However, the efficacy of viscosupplementation is variable and may be influenced by the short residence time of lubricant in the knee joint after injection. Recent studies have demonstrated the use of aldehyde (CHO) modified extracellular matrix proteins for targeted adherence to a biological tissue surface. It is hypothesized that CHO could be exploited to enhance the binding of lubricating proteoglycans to the surface of PRG4-depleted cartilage. The objective of this study was to determine the feasibility of molecular resurfacing of cartilage with CHO-modified PRG4. PRG4 was chemically functionalized with aldehyde (PRG4-CHO) and aldehyde plus Oregon Green (OG) fluorophore (PRG4-OG-CHO) to allow for differentiation of endogenous and exogenous PRG4. Cartilage disks depleted of native PRG4 were then treated with solutions of PRG4, PRG4-CHO, or PRG4-OG-CHO and then assayed for the presence of PRG4 by immunohistochemistry, ELISA, and fluorescence imaging. Repletion of cartilage surfaces was significantly enhanced with the inclusion of CHO compared with repletion with unmodified PRG4. These findings suggest a generalized approach which may be used for molecular resurfacing of tissue surfaces with PRG4 and other lubricating biomolecules, perhaps leading in the future to a convenient method for overcoming loss of lubrication during the early stages of osteoarthritis.     

Response of a PGNAA setup for pozzolan-based cement concrete specimens

Pozzolanic materials are added to Portland cement concrete to increase its durability, particularly corrosion-resistance. In this study the elemental composition of a pozzolanic cement concrete was measured non-destructively utilizing an accelerator-based Prompt Gamma Ray Neutron Activation Analysis (PGNAA) setup. The optimum size of the pozzolanic cement concrete specimen was obtained through Monte Carlo simulations. The simulation results were experimentally verified through the γ-ray yield measurement from the pozzolanic cement concrete specimens as a function of their radii. The concentration of the pozzolanic material in the cement concrete specimens was evaluated by measuring γ-ray yield for calcium and iron from pozzolanic cement concrete specimens containing 5–80 wt% pozzolan. A good agreement was noted between the experimental values and the Monte Carlo simulation results, indicating an excellent response of the KFUPM accelerator-based PGNAA setup for pozzolan based concrete.     

Determination of Myo-inositol and d-chiro-inositol in black rice bran by capillary electrophoresis with electrochemical detection

A high-performance capillary electrophoresis (CE) method with electrochemical detection (ED) is developed for simultaneous determination of myo-inositol and d-chiro-inositol in black rice bran in this work. A 140 μm diameter copper-disk electrode operated in a wall-jet configuration, which exhibited good response at +0.65 V (relative to the saturated calomel electrode (SCE)) for the two analytes in 50 mm sodium hydroxide solution, was used as working electrode. The optimum conditions for determination was optimized with regard to the potential applied to the working electrode, concentration of the running buffer, separation voltage and injection time. The analytes were separated within 20 min. Excellent linearity was obtained in the concentration range from 1.0×10⁻⁶ to 1.0×10⁻⁴ g/ml for both analytes. The detection limit (S/N=3) was 5.3×10⁻⁷ and 7.3×10⁻⁷ g/ml for myo-inositol and d-chiro-inositol, respectively. The work provides a useful method for the analysis of myo-inositol and d-chiro-inositol in black rice bran.     

壳聚糖及其衍生物在药物载体方面的研究进展

壳聚糖是一种天然聚氨基葡萄糖,具有较好的生物相容性、生物可降解性、抗菌和止血等性能。由于壳聚糖分子内及分子间存在较强的氢键作用,使得其只能溶于弱酸性溶液而不溶于水,限制了其在生物材料中的应用。壳聚糖上含有大量活泼羟基和氨基,通过衍生化反应不仅可以提高壳聚糖的水溶解性,而且可以赋予壳聚糖更多的功能化特性,例如壳聚糖衍生物用于药物传输载体,可达到缓释和控释药物的目的,提高药物的稳定性,降低药物的不良反应,从而提高药物的生物利用度。所以,壳聚糖及其衍生物已成为药物传输系统领域的研究热点。作者系统介绍壳聚糖及其衍生物的性能以及作为药物传输载体的特点,综述它们作为药物传输载体的类型及研究应用,包括最近合成含维生素B12 两亲性壳聚糖衍生物通过口服给药治疗糖尿病视网膜病变,还对壳聚糖及其衍生物在该领域的发展方向进行展望。     

一种现场快速型HBV基因分型方法及装置

介绍一种现场快速型HBV(乙型肝炎病毒)基因分型方法及装置,包括生物传感器与手持式荧光检测仪。为了提高检测灵敏度与准确性,采用荧光标记法。荧光检测仪采用简化方法来快速读取侧向流试纸上各测试线及质控线的信号幅值,基于预先建立的HBV基因分型模式匹配模型,实现快速分型。对48份HBV血清样本进行检测,实验结果表明,基于荧光检测仪及侧向流试纸的分型检测结果与传统核酸分析方法的分型检测结果一致,分型准确率达100%。与传统方法相比,现场快速型基因分型方法及装置可降低HBV分型检测的复杂度,缩短检测时间,降低检测成本,对乙肝个体化用药与个性化治疗具有重要意义。     

Familiar glioblastoma presenting as a true multicentric tumor: etiopathogenic and prognostic features

Familial glioblastoma multiforme is a rather uncommon entity, being in most cases associated to known genetic disorders (as Turcot syndrome, Li-Fraumeni syndrome, neurofibromatosis, etc.). However, familial gliomas have also been described, although less frequently, independently of these genetic syndromes showing some special features regarding its etiology and clinical manifestations. Less than 10% of gliomas may be considered as true multicentric tumours either synchronous or metachronous in clinical presentation. Metachronous glioblastomas have been associated to better prognosis in some studies, with genetic studies having found clear differences among the tumors within same patients. Familial glioblastoma with metachronous presentation is an exceptional disorder. These tumors show special therapeutic implications due to the limitations of radiotherapy once the patient has already irradiated. A variety of non-specific mutations have been found in these patients but true characterization of this disorder remains unclear and will be based on further genetic studies. We present a clinical report on a patient harbouring a familial and metachronous glioblastoma. The main aspects of this entity are reviewed.