担载血管生长因子的乳液法纤维用于血管再生的研究

目的:制备担载血管生长因子(VEGF)的乳液法静电纺丝纤维膜,对其开展一系列表征,从而研究其血管再生的潜能。方法:通过W/O乳液法制备担载VEGF的静电纺丝纤维膜,并对其形态、力学性质进行表征。用VEGF ELISA分析方法对其体外释放动力学进行研究。运用CCK-8法检测乳液法静电纺丝纤维膜中VEGF的活性变化。结果:乳液法静电纺丝纤维膜呈现连通的三维网状结构,平均直径为1μm,模拟了细胞外基质(ECM),最大拉伸应力为3.03±0.66 M Pa,具有良好的抗拉伸能力,能够支持细胞的生长。乳液法纤维膜中VEGF在体外累积释放了14天,总释放量超过20000 pg,达到血管再生的有效浓度。CCK-8结果显示,乳液法纤维膜中的VEGF仍然保持较高的蛋白活性。结论:担载VEGF的乳液法静电纺丝纤维膜能够缓释出活性的蛋白,具有血管再生的潜能。     

制备大孔径静电纺丝组织工程支架的研究进展

研究表明静电纺丝可以制备出模拟细胞外基质的三维结构,其中限制静电纺丝纤维支架应用的问题之一就是纤维排列紧密导致支架的孔径较小,从而阻碍了细胞的浸入,组织中血管化的形成以及支架与宿主细胞的融合。为了增大支架的孔径,提高孔隙率,许多研究者提出了相应的策略。本文综述了多种制备大孔径静电纺丝纤维支架的方法,主要包括不同接收装置控制电场分布、盐粒子/聚合物析出法、水浴接收、低温静电纺丝以及激光/紫外烧蚀法等,以上的方法都能够有效的增大静电纺丝三维支架的孔径,进而提高了细胞的浸润性、营养物质的传输以及废物的排出,为静电纺丝纤维支架在组织工程中的应用奠定了基础。     

静电纺丝制备担载神经生长因子的聚乳酸纤维的工艺研究

目的:研究担载神经生长因子(NGF)的聚乳酸纤维乳液法静电纺丝的制备工艺,从电压、溶液浓度等工艺条件进行探索,通过扫描电镜对纤维的形态结构进行观察,旨在找到最佳纺丝制备条件,并观察该条件下纤维的体外释放行为和细胞活性。方法:将NGF水溶液分散于聚乳酸(PLLA)溶液中,通过W/O乳液法制备静电纺丝纤维。分别从电压8 k V、10 k V、12 k V,浓度梯度90mg/m L、100 mg/m L、110 mg/m L进行静电纺丝纤维的制备,对纤维的形态等进行表征。使用ELISA对NGF体外释放动力学进行检测,用Alamer Blue试剂考察纤维释放液对于PC12悬浮细胞增殖的影响。结果:浓度和电压对电纺纤维制备影响很大。当浓度过大时,易堵塞纺丝喷头且纤维弯曲,过小时纤维粗细差异较大。电压过大或过小时纤维弯曲情况严重,甚至出现缠绕现象。当浓度为100 mg/m L,电压为10 k V时制备的乳液法静电纺丝聚乳酸纤维直径粗细均匀,具有较好形态。在该条件下的制备的纤维NGF体外有效释放13天,释放液可以促进PC12细胞的增殖。结论:担载NGF的聚乳酸纤维乳液法最佳静电纺丝制备条件为:PLLA溶液浓度100 mg/m L、电压10 k V,该条件下制备的担载NGF的聚乳酸纤维体外释放可累计释放13天,其释放液可有效促进PC12细胞的增殖,为进一步研究担载NGF的聚乳酸纤维导管奠定了一定的工艺基础。     

新型生物医用材料—止血纤维的制备与应用研究

作者以高分子生物医用材料,采用气体牵伸纺丝技术,制备了医用止血纤维。经止血机理及结构的研究,其在外伤止血、护创和手术局部止血方面疗效显著。     

共载TFPI-2及顺铂磁性纳米复合物的制备及其对鼻咽癌的治疗

构建共载组织途径抑制因子-2(tissue factor pathway inhibitor-2,TFPI-2)及顺铂(cisplatin,CDDP)的磁性纳米(magnetic nanoparticles,MNP)复合物(MNP-CDDP/TFPI-2),研究该复合物对鼻咽癌(nasopharyngeal carcinoma,NPC)的综合抑制效应。将前期制备的载CDDP磁性纳米颗粒(MNP-CDDP)和聚乙二醇单甲醚–聚乙烯亚胺(MPEG-PEI)TFPI-2静电吸附,制备MNP-CDDP/TFPI-2,通过红外光谱、透射电镜、激光粒度仪观察复合物的结构、粒径大小及电位,邻苯二胺(o-phenylenediamine,OPDA)法检测复合物中CDDP含量。通过流式细胞仪检测基因转染效率,分析磁性纳米复合物转染TFPI-2的情况;RT-PCR及Western blot法检测CNE-2细胞转染TFPI-2质粒后TFPI-2 m RNA和蛋白表达情况。采用CCK-8实验、流式细胞术及Matrigel侵袭实验检测MNPCDDP/TFPI-2对CNE-2细胞增殖、凋亡及细胞侵袭能力的影响。研究结果显示,纳米复合物成功合成,平均水动力学粒径151.2 nm,Zeta电位+14.5 m V,复合物中CDDP含量平均为120μg/m L,包封率33.3%。复合物所载TFPI-2质粒转染率22.7%±2.5%。CNE-2转染TFPI-2质粒后,胞内TFPI-2 m RNA和蛋白表达明显增加。MNP-CDDP/TFPI-2组细胞生长抑制率及凋亡率分别为34.8%和42.3%,明显高于MNP-CDDP组(27.1%、38.0%)和(MPEG-PEI)TFPI-2组(18.9%、16.2%)(P0.05)。Matrigel侵袭实验结果显示,纳米复合药物组穿膜细胞数为28±3个,明显低于对照组(P0.05),提示MNP-CDDP/TFPI-2组细胞侵袭和迁移能力降低。结果表明,本研究已成功构建携带TFPI-2表达基因及CDDP的MNP-CDDP/TFPI-2;体外实验显示,MNP-CDDP/TFPI-2对NPC细胞具有良好的综合抑制效应。     

静电纺丝用作难愈合伤口敷料的研究进展

静电纺丝伤口敷料作为一种新型功能性敷料,具有较大的比表面积、可调控的孔隙率和良好的生物性能,既有益于细胞呼吸,又 可抑制细菌感染伤口,并能促进细胞增殖和加速创面愈合,是未来伤口敷料研发领域发展的新方向。介绍静电纺丝纳米纤维的原理、特点, 重点阐述各类聚合物、生物活性物质在静电纺丝伤口敷料制备中的应用进展。     

PLLA短纤维涂覆多孔HA支架的制备

细胞外基质的重要成分——胶原蛋白,主要以纳米纤维的形式存在并构成纳米纤维多孔网架,因此,构建具有类细胞外基质结构的仿生支架可能为细胞在体外的生长提供理想的微环境。本实验中,采用静电纺丝技术制备聚乳酸纳米纤维,并采用铜板切片法对纤维膜进行短切得到PLLA短切纤维,其中,单根纤维的长度在500μm左右。选用海藻酸钠作为PLLA短纤维的分散剂,将PLLA短纤维均匀的分散在海藻酸钠溶液中,形成短纤维的悬浊液,然后在多孔羟基磷灰石支架表面均匀的涂覆,用氯化钙交联海藻酸钠使纤维固定在支架表面。制得纤维复合支架。用扫描电镜观察复合支架微观形貌可观察到支架表面纤维分散均匀,并且未出现堵孔现象。     

新型聚乙烯亚胺衍生物在COS-7细胞中转染和毒性的研究

目的：研究以乙二醛为连接剂的聚乙烯亚胺（Polyethyleneimine,PEI）衍生物Polyimine-PEI对非洲绿猴肾癌细胞COS-7的转染活性和细胞毒性的影响。方法：以荧光素酶质粒为报告基因,研究高分子与DNA的复合物在COS-7细胞的转染活性,用MTT方法研究高分子对COS-7细胞的毒性。结果：COS-7细胞实验显示,Polyimine-PEI具有很低细胞毒性,其毒性显著低于PEI25kDa,同时也具有高效输送质粒的能力。结论：Polyimine-PEI是一种新型的高效,低毒在基因治疗领域有相当前景的非病毒载体。     

新型聚乙烯亚胺衍生物在COS-7 细胞中转染和毒性的研究

目的:研究以乙二醛为连接剂的聚乙烯亚胺(Polyethyleneimine,PEI)衍生物Polyimine-PEI对非洲绿猴肾癌细胞COS-7的转染活性和细胞毒性的影响。方法:以荧光素酶质粒为报告基因,研究高分子与DNA的复合物在COS-7细胞的转染活性,用MTT方法研究高分子对COS-7细胞的毒性。结果:COS-7细胞实验显示,Polyimine-PEI具有很低细胞毒性,其毒性显著低于PEI25kDa,同时也具有高效输送质粒的能力。结论:Polyimine-PEI是一种新型的高效,低毒在基因治疗领域有相当前景的非病毒载体。     

新型聚乙烯亚胺衍生物在Hep G2 细胞中转染和毒性的研究

目的:研究以对苯二甲醛( Terephthalaldehyde)为连接剂的聚乙烯亚胺(Polyethyleneimine,PEI)衍生物PEI-Tp对肝癌细胞Hep G2的转染活性和细胞毒性的影响.方法:以荧光素酶质粒作为报告基因,研究高分子和DNA的复合物在Hep G2细胞中的转染活性,用MTT的方法研究高分子对Hep G2细胞的毒性.结果:Hep G2细胞转染结果显示构建的聚乙烯亚胺衍生物PEI-Tp具有高效输送质粒的能力;细胞毒性结果显示PEI-Tp随着浓度的增加,其毒性显著低于PEI25 kDa.结论:Hep G2细胞实验数据显示PEI-Tp是一种高效、低毒,在基因治疗领域有相当前景的非病毒载体.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细