聚乙二醇—硝酸镧配位聚合物的表征研究

以聚乙二醇(PEG)为配位体,首次合成了三价稀土金属镧与PEG的配位聚合物。实验测定了该配位聚合物的红外光谱、示差扫描量热谱(DSC)、热失重分析(TGA)和凝胶渗透色谱(GPC),并就配位反应、热分解以及配位前后分子流体力学体积的变化进行了讨论。     

Efficacy and Safety of Hemoglobin-Polyethylene Glycol Conjugate (Pyridoxalated Polyethylene Glycol Hemoglobin) as an Oxygen-Carrying Resuscitation Fluid

Abstract: The safety and efficacy of a conjugate of pyridoxalated hemoglobin and polyethylene glycol (pyridoxalated PEG hemoglobin) were evaluated after administration to rats. The LD₅₀ (lethal dose for 50% survival of group) of pyridoxalated polyethylene glycol (PEG) hemoglobin was >200 ml/kg. Any pro-or anticoagulation activity was not demonstrated in in vitro coagulation tests. One day after 70% exchange-transfusion with pyridoxalated PEG hemoglobin, slight elevations of the serum glutamic-oxaloacetic transaminase, serum glutamie-pyruvic transaminase, and blood urea nitrogen values, which were 101.7 ± 22.6 IU/L, 33.3 ± 7.2 IU/L, and 23.1 ± 1.4 mg/dl, respectively, were observed. However, these values were in the normal range after 3 days. With >90% exchange-transfusion, all rats exchange-transfused with pyridoxalated PEG hemoglobin survived for >2 weeks in contrast to the death of all the rats exchangetransfused with stroma-free hemoglobin or albumin.     

A polyethylene glycol grafted bi-layered polyurethane scaffold: preliminary study of a new candidate prosthesis for repair of a partial tracheal defect

The purpose of this study was to develop an artificial prosthesis for use in the reconstruction of a tracheal defect due to trauma, malignancy, stenosis, or other causes. Bi-layered porous-dense film polyurethane (PU) was manufactured for the main framework. Polyethylene glycol (PEG) was grafted onto the inner surface of the PU scaffold to act as a surfactant. The scaffold was transplanted into three beagles. An endoscopic examination was performed for the evaluation of the formation granulation tissue, to evaluate the status of the respiratory mucosa and the amount of crust at 1, 4, 8, and 12 weeks after surgery. A histological examination was also performed at 4, 8, and 12 weeks after surgery. All three beagles studied survived to the expected date. The endoscopic examination showed formation of granulation tissue; the crust was not very severe and the circular tracheal framework was well preserved. The histological examination showed that a large amount of fibrous tissue had grown through the pores of the porous scaffold. Pseudostratified columnar ciliated mucosa was also noted on the surface of scaffold, as visualized by scanning electron microscopy. The use of a bi-layered polyethylene grafted polyurethane scaffold is a good candidate prosthesis for tracheal reconstruction.     

脂肪间充质干细胞移植治疗兔急性心肌梗死的实验研究

目的探讨脂肪间充质干细胞(adipose tissue-derived mesenchymal stem cells,ADMSCs)移植治疗兔急性心肌梗死后心力衰竭的作用及其可能机制。方法 30只健康日本大耳白兔随机分为注射磷酸盐缓冲液的假手术组(n=10)、心肌梗死对照组(n=10)以及注射ADMSCs移植组(n=10)。结扎兔前室间支,建立急性心肌梗死动物模型,急性心肌梗死1h内将4',6-二脒-2-苯基吲哚(4',6-diamidio-2-phenylindole,DAPI)标记的第三代ADMSCs(5×106个,1mL)植入ADMSCs移植组梗死心肌,对照组及假手术组注射等量磷酸盐缓冲液液。术前及术后4周分别做超声心动图检查其心功能变化。取心肌梗死区组织作冰冻切片,荧光显微镜下验证移植后的ADMSCs是否向心肌细胞分化,苏木素-伊红染色和CD34免疫组化观察梗死区毛细血管新生情况。结果超声心动图检测证实移植后4周ADMSCs组左心室收缩末期直径、舒张末期直径与左心室重量指数均小于心肌梗死对照组[(0.72±0.04)cm vs.(0.88±0.07)cm,P0.05;(1.07±0.12)cm vs.(1.21±0.09)cm,P0.05;(1.176±0.057)g/kg vs.(1.361±0.095)g/kg,P0.05],而短轴缩短率、射血分数均大于心肌梗死对照组[31.87%±2.03%vs.28.00%±3.38%,P0.05;51.75%±3.37%vs.43.13%±3.72%,P0.05];ADMSCs移植组荧光显微镜下可以观察到DAPI标记细胞存在,并分化为心肌样细胞;CD34免疫组化染色显示ADMSCs组梗死局部毛细血管密度明显高于心肌梗死对照组[(20.00±2.65)个vs.(7.75±2.12)个,P0.05]。结论同种异体移植的ADMSCs能够在梗死心肌内存活并分化为心肌样细胞,增加梗死区血管新生,抑制心室重构、改善心肌梗死后心功能。     

聚乙二醇干扰素α-2a与恩替卡韦治疗慢性乙型肝炎的对照研究

目的 观察聚乙二醇干扰素α-2a与恩替卡韦治疗ALT＜2倍正常值上限(ULN)且肝组织学炎症活动度(G)≥2的慢性乙型肝炎(乙肝)患者的疗效和安全性.方法 采用开放、对照的研究方法,符合人选标准的慢性乙肝患者100例予以聚乙二醇干扰素α-2a或恩替卡韦治疗.聚乙二醇干扰素α-2a组50例,其中HBeAg阳性34例;恩替卡韦组50例,其中HBeAg阳性33例.治疗48周进行评估.数据行方差分析、t检验、Wilcoxon检验和X~2检验.结果 聚乙二醇干扰素α-2a组和恩替卡韦组基线HBV DNA、ALT、HBeAg、HBsAg水平和肝组织学特征均具有可比性.治疗48周,聚乙二醇干扰素α-2a组和恩替卡韦组各50例患者血清HBV DNA阴转率分别为66.0%和72.0%(X~2=0.421,P=0.517),聚乙二醇干扰素α-2a组患者血清HBV DNA较基线下降(3.08±1.43)lg拷贝/mL,恩替卡韦组下降(3.79±1.36)lg拷贝/mL(t=2.544,P=0.013).聚乙二醇干扰素α-2a组HBsAg阴转5例,占10.0%,恩替卡韦组阴转1例,占2.0%(X~2=2.837,P=0.204);聚乙二醇干扰素α-2a组HBsAg血清转换3例,占6.0%,恩替卡韦组无转换患者(X~2=3.093,P=0.242).聚乙二醇干扰素α-2a组HBeAg阳性的34例患者中,有14例发生HBeAg阴转和血清转换,占41.2%,恩替卡韦组HBeAg阳性的33例患者中,5例发生HBeAg阴转,4例HBeAg血清转换(X~2=5.583,P=0.018;X~2=7.159,P=0.007).聚乙二醇干扰素α-2a组有15例、恩替卡韦组有14例患者治疗前后均行肝组织活检,治疗48周后肝组织学改善(Knodell评分下降2分以上)分别是11例和9例(X~2=0.277,P=0.599).结论 聚乙二醇干扰素α-2a治疗ALT＜2×ULN且肝组织学G≥2的慢性乙肝患者可获得良好的病毒学、血清学应答和组织学改善,且安全性好.聚乙二醇干扰素α-2a治疗后HBeAg血清转换率显著优于恩替卡韦.     

器官保存液中聚乙二醇对人红细胞聚集性和血液流变学的影响

背景：聚乙二醇作为一种非渗透性大分子物质,在器官保存液中可发挥保护细胞膜、维护细胞骨架完整性、防止细胞水肿、抗脂质过氧化和免疫调节的作用。 目的：探讨器官保存液中的聚乙二醇对人红细胞聚集性和血液流变学的影响。 设计、时间及地点：对比观察实验,于2008-10在解放军第二军医大学附属长征医院器官移植科完成。 材料：抽取接受体格检查的6名健康志愿者的肘前静脉血。 方法：在抽取的新鲜血液中按5∶1的稀释比分别加入生理盐水、器官保存液及含不同相对分子质量、不同浓度聚乙二醇的多器官保存液,按加入液体的不同分为：生理盐水组、器官保存液组、不添加聚乙二醇的保存液组、20聚乙二醇1,10,30 g/L和35聚乙二醇1,10,30 g/L组。 主要观察指标：室温下通过魏氏法检测红细胞沉降率、自动血液流变仪检测血液流变学指标、光镜观察红细胞聚集的形态学改变,分析聚乙二醇对人红细胞聚集性和血液流变学的影响。 结果：不含胶体的保存液对红细胞聚集无影响,含低浓度聚乙二醇的保存液对红细胞聚集性和血液流变学的影响较小,器官保存液组、20聚乙二醇30 g/L,35聚乙二醇10 g/L和35聚乙二醇30 g/L的保存液则可显著加快红细胞沉降率,降低红细胞变形能力,引起红细胞明显聚集。 结论：器官保存液中的聚乙二醇可引起红细胞聚集,降低红细胞变形能力,其相对分子质量越大,浓度越高,促进红细胞聚集的作用越明显,对血液流变学的影响越大。     

抗黏附多肽的聚乙二醇化研究

目的 观察聚乙二醇化抗黏附多肽酪-异亮-甘-丝-精(YIGSR)对人肝癌高转移细胞株MHCC97H体外基质黏附抑制能力和在大鼠血清体外的降解.方法 将甲氧基聚乙二醇丙醛10000(mPEGALD10000)与YIGSR在PH4到6,摩尔比1:1到10:1条件下偶联成聚乙二醇化YIGSR(PEG-YIGSR).比较两者的基质黏附抑制能力及在SD大鼠血清中的降解速率.结果 修饰率可以达到99.9%以上,PEG-YIGSR的黏附抑制率达19.5%,且呈时间剂量依赖关系.PEG-YIGSR在大鼠血清中的降解速度明显慢于YIGSR,药时曲线下面积(AUC)分别为(1249±36)mg/min·L~(-1)和(1146±47)mg/min·L~(-1).结论 PEG-YIGSR保留了抗肿瘤细胞黏附的作用,且在体外血清中的降解速率减慢,有助于延长YIGSR发挥作用的时间.     

基因1b型丙型肝炎病毒NS5A区变异及其与聚乙二醇干扰素α-2a联合利巴韦林治疗应答的相关性

目的探讨基因1b型慢性丙型肝炎患者NS5A区基因变异与聚乙二醇干扰素α-2a（PEG—IFNα-2a）联合利巴韦林（RBV）抗病毒治疗疗效的关系。方法回顾性选择15例应用PEG—IFNα-2a／RBV抗病毒治疗的基因1b型慢性丙型肝炎患者,其中7例为快速应答（RVR）,8例为无应答（NR）,应用RT—PCR法扩增NS5A全长片段,用克隆测序方法进行核苷酸和氨基酸序列测定。结果没有发现与治疗应答相关的单个氨基酸或基序变异,RVR组和NR组在NS5A、ISDR、PKRBD和IRRDR区的氨基酸突变数目差别均无统计学意义,RVR组在V3区（aa2356～2379）的氨基酸突变数目高于NR组（分别为5．3±0.5和3．4±0．6,P=0．03）。结论V3区的氨基酸突变数目与PEG—IFNα-2a联合RBV抗病毒疗效可能相关。     

Uptake and transfection efficiency of PEGylated cationic liposome–DNA complexes with and without RGD-tagging

Steric stabilization of cationic liposome–DNA (CL–DNA) complexes is required for in vivo applications such as gene therapy. PEGylation (PEG: poly(ethylene glycol)) of CL–DNA complexes by addition of PEG2000-lipids yields sterically stabilized nanoparticles but strongly reduces their gene delivery efficacy. PEGylation-induced weakening of the electrostatic binding of CL–DNA nanoparticles to cells (leading to reduced uptake) has been considered as a possible cause, but experimental results have been ambiguous. Using quantitative live-cell imaging in vitro, we have investigated cell attachment and uptake of PEGylated CL–DNA nanoparticles with and without a custom synthesized RGD-peptide grafted to the distal ends of PEG2000-lipids. The RGD-tagged nanoparticles exhibit strongly increased cellular attachment as well as uptake compared to nanoparticles without grafted peptide. Transfection efficiency of RGD-tagged PEGylated CL–DNA NPs increases by about an order of magnitude between NPs with low and high membrane charge density (σ_M; the average charge per unit area of the membrane; controlled by the molar ratio of cationic to neutral lipid), even though imaging data show that uptake of RGD-tagged particles is only slightly enhanced by high σ_M. This suggests that endosomal escape and, as a result, transfection efficiency of RGD-tagged NPs is facilitated by high σ_M. We present a model describing the interactions between PEGylated CL–DNA nanoparticles and the anionic cell membrane which shows how the PEG grafting density and membrane charge density affect adhesion of nanoparticles to the cell surface.