Biocompatibility of a New Calcium Silicate-Based Root Canal Sealer Mediated via the Modulation of Macrophage Polarization in a Rat Model

(1) Background: The EndoSequence BC Sealer HiFlow (Brasseler, Savannah, GA, USA) has recently been introduced in clinical applications. Thus, the aims of the present study are to determine its biocompatibility in vivo and to examine its ability to drive macrophage polarization in vitro and in vivo. (2) Methods: HiFlow was implanted into rat connective tissue for 7, 30 and 150 days. The microstructures and elemental compositions were determined by scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX). Hematoxylin–eosin, immunofluorescence, RT–qPCR and flow cytometry were used to elucidate the effects on inflammatory responses and macrophage polarization. (3) Results: SEM-EDX revealed the formation of surface hydroxyapatite crystal layers. Histological evaluation showed that HiFlow exhibited long-term biocompatibility because it decreased inflammatory responses and reduced the number of macrophages over time; however, tissue necrosis was observed in all the groups. RT–qPCR verified that HiFlow regulated the expression of inflammatory factors to inhibit the inflammatory response. Immunofluorescence analysis performed on in vivo samples revealed that HiFlow promoted M2-like macrophage polarization, and these results were confirmed by flow cytometry in vitro. (4) Conclusion: After 150 days of investigation, HiFlow was considered biologically acceptable, and the formation of apatite crystal layers and the promotion of M2-like macrophage polarization may contribute to its favorable biocompatibility.     

PEG-g-chitosan thermosensitive hydrogel for implant drug delivery: cytotoxicity,in vivo degradation and drug release

Thermosensitive hydrogels based on chitosan are of great interests for injectable implant drug delivery. The poly(ethylene glycol)-grafted-chitosan (PEG-g-CS) hydrogel was reported as a potential thermosensitive system. The objective of the present study is to evaluate the cytotoxicity, in vivo degradation and drug release of PEG-g-CS hydrogel. Cytotoxicity was evaluated using L929 murine fibrosarcoma cell line. Degradation and drug release in vivo were investigated by subcutaneous injection of the hydrogel into Sprague-Dawley rats. PEG-g-CS polymer exhibits no significant cytotoxicity when its concentration is less than 3 mg mL^?1. After being implanted, PEG-g-CS hydrogel maintains its integrity for two weeks and collapses, merging into the tissue, in the third week. It causes moderate inflammatory response but no fibrous encapsulation around the hydrogel is found. The hydrogel presents a three-week sustained release of cyclosporine A with no significant burst release in vitro and produces the effective drug concentration in blood for more than five weeks in vivo, performing almost the same bioavailability to chitosan/glycerophosphate hydrogel. Further modifications of PEG-g-CS hydrogel might be necessary to modulate the degradation and to mitigate the fluctuations in blood drug concentration.     

Examination of fabrication conditions of acrylate-based hydrogel formulations for doxorubicin release and efficacy test for hepatocellular carcinoma cell

The objective of the present study was to develop 2-hydroxypropyl methacrylate-co-polyethylene methacrylate [p(HPMA-co-PEG–MEMA)] hydrogels that are able to efficiently entrap doxorubicin for the application of loco-regional control of the cancer disease. Systemic chemotherapy provides low clinical benefit while localized chemotherapy might provide a therapeutic advantage. In this study, effects of hydrogel properties such as PEG chains length, cross-linking density, biocompatibility, drug loading efficiency, and drug release kinetics were evaluated in vitro for targeted and controlled drug delivery. In addition, the characterization of the hydrogel formulations was conducted with swelling experiments, permeability tests, Fourier transform infrared, SEM, and contact angle studies. In these drug-hydrogel systems, doxorubicin contains amine group that can be expected a strong Lewis acid–base interaction between drug and polar groups of PEG chains, thus the drug was released in a timely fashion with an electrostatic interaction mechanism. It was observed that doxorubicin release from the hydrogel formulations decreased when the density of cross-linking, and drug/polymer ratio were increased while an increase in the PEG chains length of the macro-monomer (i.e. PEG–MEMA) in the hydrogel system was associated with an increase in water content and doxorubicin release. The biocompatibility of the hydrogel formulations has been investigated using two measures: cytotoxicity test (using lactate dehydrogenase assay) and major serum proteins adsorption studies. Antitumor activity of the released doxorubicin was assessed using a human SNU398 human hepatocellular carcinoma cell line. It was observed that doxorubicin released from all of our hydrogel formulations which remained biologically active and had the capability to kill the tested cancer cells.     

Effect of topology of poly(L-lactide-co-ε-caprolactone) scaffolds on the response of cultured human umbilical cord Wharton’s jelly-derived mesenchymal stem cells and neuroblastoma cell lines

In this study, for the first time, a biodegradable poly(L-lactide-co-ε-caprolactone), PLC 67:33 copolymer was developed for use as temporary scaffolds in reconstructive nerve surgery. The effect of the surface topology and pore architecture were studied on the biocompatibility for supporting the growth of human umbilical cord Wharton’s jelly-derived mesenchymal stem cells (hWJ-MSCs) and human neuroblastoma cells (hNBCs) as cell models. Porous PLC membranes were prepared by electrospinning and phase immersion precipitation with particulate leaching and nonporous PLC membranes were prepared by solvent casting. From the results, the porous PLC membranes can support hWJ-MSCs and hNBCs cells better than the nonporous PLC membrane, and the interconnected pore scaffold prepared by electrospinning exhibited a more significant supporting attachment of the cells than the open pore and nonporous membranes. We can consider that these electrospun PLC membranes with 3-D interconnecting fiber networks and a high porosity warrant a potential use as nerve guides in reconstructive nerve surgery.     

脂肪源干细胞与聚丙烯网片的生物相容性研究

目的观察脂肪源干细胞(ADSCs)与聚丙烯网片的生物相容性。方法制备兔ADSCs悬液。取聚丙烯网片浸提液培养ADSCs。用四甲基偶氮唑盐(MTT)法检测细胞活力,评价支架细胞毒性。ADSCs传代扩增后,接种到聚丙烯网片支架上,体外培养1周。用扫描电子显微镜观察细胞在支架上黏附生长及增殖。结果 ADSCs在聚丙烯网片浸提液中可保持较高的增殖率(RGR)(24、48、72 h实验组细胞RGR分别为97%、96%、101%,平均RGR为103.5%),与对照组比较,差异无统计学意义(χ2=17.45,P0.05),聚丙烯网片浸提液无细胞毒性。脂肪干细胞种植于两种支架材料后生长速度快,扫描电子显微镜观察可见脂肪干细胞呈球型,并伸展形成伪足,贴附于支架材料,细胞间相互连接成团。结论聚丙烯网片支架与ADSCs具有良好的生物相容性,无细胞毒性,可作为脂肪组织工程较理想的生物支架材料。     

氟涂层镁铝合金的体外生物相容性研究简

目的 研究氟涂层镁铝合金的体外生物相容性。方法实验分为空白对照组（N组）、镁铝合金组（M组）、氟涂层镁铝合金组（F组）和阳性对照组（P组）4组。细胞毒性实验：将L929细胞在各组的DMEM浸提液中培养,光学显微镜下观察细胞生长状况。应用WST-1法测量光密度（OD）值。溶血实验：按GB-T16175-2008《医用有机硅材料生物学评价实验方法》第13部分《溶血试验》进行实验。测量各样本的OD值,计算溶血率。豚鼠最大剂量致敏实验,按照GBJ16886.10-2005（（医疗器械生物学评价》第10部分《刺激与迟发型超敏反应试验》进行实验。观察激发阶段去除贴附片后24、48、72h豚鼠皮肤致敏情况。结果各观察期F组的形态分级为0级,M组为4级。各组各观察期内OD值差异均有统计学意义（F=312.96,P=0.000）。第3天,实验组OD值均高于P组（1.050±0.065 vs 0.292±0.010）（P〈0.05）。第5天、第7天,F组与N组OD值（1.429±0.096 vs 1.622±0.156,0.928±0.040 vs 50.995±0.070）处于同一水平（P〉0.05）,均高于P组（0.270±0.015,0.281±0.006）（P〈0.05）。M组溶血率为68.3％,F组为0.8％。24h、48h和72h后N组、M组、F组皮肤均无红斑。结论氟涂层镁铝合金体外实验显示具有良好的生物相容性。     

Convenient Synthesis of a Polyester‐co‐Polyether Block for Assembling Biocompatible Hyperbranched Macromolecules

Synthesis of a novel multifunctional block based on asymmetrically substituted pentaerythritol, succinic acid, and tetraethylene glycol is reported. The proposed reaction conditions allow selective preparation of the product in high overall yield. The block can be used in the assembly of biocompatible polyester‐co‐polyether (PEPE) hyperbranched macromolecules, which allows the product to be considered as a promising intermediate for the development of new biomedical dendrimers. As an example, the use of the “block by block” strategy is employed to obtain a second‐generation dendron. It is shown that the approach is much more efficient than the pathway of step‐by‐step grafting of separate molecular fragments.

     

类骨质羟磷灰石和自体骨修复兔下颌骨临界性骨缺损的研究

目的探讨类骨质羟磷灰石（SBR）的生物相容性,并探讨该替代材料和自体骨混合修复骨缺损的生物学特性。方法选用新西兰大白兔,在实验动物双侧下颌骨内侧形成10 mm×10 mm×2 mm大小的临界性缺损,左侧骨缺损按照1∶1比例植入SBR和自体骨,右侧骨缺损内分别植入自体骨或缺如,术后2、4、8周取标本,进行大体标本、X线、组织学和Masson新三色染色法的形态学分析。结果生物替代物具有良好的生物相容性,与自体骨混合能有效地促进骨缺损的修复愈合。骨髓细胞很容易在该材料表面黏附,自体骨的加入更有利于新骨长入材料的孔隙中,分化增殖,形成骨基质,并钙化成熟。结论SBR是一种良好的骨替代材料,自体骨的加入更有利于早期成骨和替代材料的自我改建的完成。     

αβ and γδ T cell subsets in chronic renal failure in children on dialysis treatment

BACKGROUND: Impaired immunity, particularly cell-mediated, is one of the features of chronic renal failure. This also concerns impaired T cell dependent responsiveness. METHODS: The expression of T cell surface antigens (CD3, CD25, TCRalphabeta, TCRgammadelta) was evaluated on peripheral blood (PB) mononuclear cells using two-color flow cytometry in 10 children on continuous ambulatory peritoneal dialysis (CAPD) and in 13 children on maintenance hemodialysis (HD) with polysulfone and cuprophane dialysers. RESULTS: In HD children absolute numbers of leukocytes, lymphocytes, CD3+, alphabeta, gammadelta T cells and a percentage of gammadelta T cells were decreased versus healthy children. Also, we observed a relative increase of CD3+, CD3+/CD25+ and alphabeta T cells after sessions with cuprophane membranes, and an increase of CD3+/CD25+, alphabeta T cell percentages after sessions with the polysulfone membranes. Additionally we found a decrease of both relative and absolute numbers of gammadelta T cells after HD with polysulfone. In CAPD children we found declined absolute numbers of total lymphocytes, CD3+ and alphabeta T cells and higher relative values of CD3+ and alphabeta T cells versus controls. CONCLUSIONS: The T cell depletion in chronic renal failure (CRF) patients primarily results from uremic-related toxicities, rather than from CAPD or HD-related incompatibilities. We showed a significant decrease of gammadelta T cells in CRF patients on HD, that may be partly responsible for impaired T-dependent responsiveness in that group. The intradialytic changes of gammadelta Tcells may result from a different degree of biocompatibility during the application of various dialysis membranes.     

股骨近端骨纤维结构不良伴髋内翻畸形的髓内固定疗效

背景：股骨近端骨纤维结构不良伴髋内翻畸形必须进行外科矫形治疗,尽量恢复股骨正常的生物力线。目前尽管截骨矫形方案很多,但楔形外翻截骨已成主流,矫形后单纯外固定并发症较多,螺钉、钉-板系统等髓外固定存在问题较多,难以获得长期稳定的治疗效果,有研究表明,股骨近端处楔形外翻截骨、交锁髓内针内固定可获得较好的中长期治疗效果。 目的：观察股骨近端骨纤维结构不良伴髋内翻畸形的髓内固定的治疗方法及生物相容性。 方法：纳入23例股骨近端髋内翻伴肢体短缩畸形的股骨近端骨纤维结构不良患者,颈干角为56°-110°,平均79°,股骨相对长度较对侧短缩1.9-8.9 cm,平均4.0 cm。所有患者均行股骨近端处楔形外翻截骨、病灶清除、取肋骨植骨、交锁髓内钉内固定。 结果与结论：固定后19例获得随访,随访时间6个月至2年,平均1年。所有内固定物均牢靠。股骨生物力线均基本矫正,截骨面处达骨性愈合,髋内翻畸形的颈干角矫正为90°-125°,平均112°,股骨相对长度矫正后较固定前延长1.5-2.5 cm,平均2.0 cm,所有患者髋关节功能影响不明显。固定后19例患者中3例正常行走无跛行,7例扶双拐行走,5例扶单拐行走,4例不扶拐轻度跛行。固定后19例患者中12例疼痛消失,6例疼痛明显缓解,加重并出现新疼痛1例。所有患者固定后均无感染、再骨折及畸形进展。结果证实,股骨近端处楔形外翻截骨、病灶清除、取肋骨植骨、交锁髓内钉内固定治疗股骨近端髋内翻伴肢体短缩畸形的股骨近端骨纤维结构不良效果良好,不仅可减少植骨量、充分矫正畸形及预防复发,而且中期随访观察证实截骨面处达到骨性愈合,髋关节功能改善良好,生物相容性较好。