枝化状聚乙二醇交联改善猪去细胞主动脉瓣的力学性能比较

Objective Branched polyethylene glycols (PEG) with different molecular weight were cross-linked to the porcine decellularized aortic valve (DAV) and the effects of PEG cross-linking on the mechanical properties were investigated. Methods A total of 25 porcine DAVs were randomly assigned into 5 groups: PEG3400, PEG8000, PEG12000, PEG20000 and control. The reactive time was 4 h at room temperature. The efficiency of crosslinking was calculated by measuring the residual thiol group. The mechanical properties were obtained by static tensile test. Results The efficiency of crosslinking was 92. 40% , 89. 88% , 87. 87% and 87. 46% in PEG3400, PEG8000, PEG12000, PEG20000 groups, respectively. As compared with other groups, the PEG3400 group had significantly greater increase in the crosslinking degree (P ＜ 0. 05). Tensile test showed the tensile strength of PEG12000 and PEG20000 groups was (3. 22 ±0.41) and (3. 19 ±0. 15) MPa, respectively, and significantly different from that in control group (P ＜ 0. 05). The tensile strength and young' s modulus had a positive correlation with the molecular weight of PEG. Conclusion Branched PEG with the molecular weight of 12 000 Da and 20 000 Dacan effectively crosslink to the porcine decellularized aortic valves and improve their mechanical behaviors, and has the potential to be used as the material of fabricating new hybrid scaffold of tissue engineering heart valves.     

完全性大动脉转位的冠状动脉分类及处理

完全性大动脉转位是一种婴幼儿常见的发绀型先心病,目前大动脉调转术已成为完全性大动脉转位的首选治疗方案。术中冠状动脉移植是手术成功的关键,特别是复杂冠状动脉畸形的移植,成功的处理可明显降低手术病死率及术后冠状动脉事件发生率。由于冠状动脉畸形的类型繁多,采用的手术方法也多样化,相同的冠状动脉畸形可采用不同的移植方法。如何更好地完成畸形冠状动脉的移植以及降低术后冠状动脉事件的发生率仍在不断地摸索中。     

聚乙二醇交联去细胞瓣构建组织工程瓣膜复合支架

目的 采用分子量20 kDa 的枝化状丙烯酰化聚乙二醇(PEG)交联巯基化去细胞瓣,构建组织工程瓣膜复合支架,并对支架的结构稳定性、力学性能和细胞相容性进行初步检测.方法 取猪新鲜主动脉瓣叶,进行脱细胞瓣处理,制备去细胞瓣并巯基化.戊二醛固定去细胞瓣,PEG 交联巯基化去细胞瓣.形态学观察去细胞及交联效果,差示扫描量热法(DSC)测定热收缩温度,Ⅰ型胶原酶溶液测定其抗酶性分解能力,拉伸实验测定其抗拉强度和弹性模量,并采用AlamarBlue 法测定支架对MRC-5 人胚肺细胞的细胞毒性.结果 HE 染色和扫描电镜(SEM)显示去细胞完全,细胞外基质保存完整;PEG 交联后瓣叶变薄,纤维增粗呈束.PEG 交联瓣的热收缩温度为(75.16 ±0.69)℃,与去细胞瓣[(67.63 ±1.09)℃]相比有显著提高,其差异有统计学意义(P ＜0.05).PEG 交联瓣6 h 及12 h酶性分解率分别为(17.52 ±1.69)%和(48.83 ±2.67)%,与去细胞瓣[(64.91 ±2.05)%和(98.23 ±1.20)%]相比,分解率显著下降.PEG 交联瓣抗拉强度较去细胞瓣显著为高,并达到天然瓣水平,弹性模量则远高于其他各组.细胞毒性试验显示PEG 组和对照组活力细胞差别为(1.82 ±0.03)%,无统计学意义(P ＞0.05).结论 PEG 交联可显著改善去细胞瓣结构稳定性和力学性能,而无明显细胞毒性,有望用于组织工程瓣膜复合支架的构建.     

人脐带血内皮祖细胞与血管内皮生长因子和碱性成纤维细胞生长因子共培养及其增殖和迁移能力

背景：目前组织工程心脏瓣膜再内皮化种子细胞主要来源于成熟内皮细胞,内皮祖细胞作为内皮细胞的前体细胞越来越受到人们的关注。 目的：分离和扩增人脐带血内皮祖细胞,观测其体外生物学特性。 方法：密度梯度离心法分离新鲜的脐血中单个核细胞,在含血管内皮生长因子和碱性成纤维细胞生长因子的培养液中培养扩增,通过形态学、免疫荧光和流式细胞仪等对贴壁细胞进行鉴定;并与脐静脉内皮细胞进行增殖和迁移能力比较。 结果与结论：随着培养和诱导时间延长,贴壁细胞形态发生明显的改变,从小圆形变成梭形,逐渐分化成典型成熟内皮细胞的鹅卵石样形态,并可形成特征性的克隆;体外诱导7 d后90%以上贴壁细胞呈Dil-ac-LDL和FITC-UEA-I双阳性;贴壁细胞流式细胞仪分析显示：培养7 d的细胞VEGFR-2、CD34和CD133表达分别占(77.4±4.9)%、(52.4±6.6)%和(19.4±2.1)%,培养28 d的细胞VEGFR-2和CD34表达分别占(81.1±7.4)%和(7.6±3.1)%,而未检测到CD133表达;人内皮祖细胞增殖和迁移能力明显高于人脐静脉内皮细胞(P < 0.05),并且细胞数量可扩增达10⁹ L^-1。结果显示用密度梯度离心法和贴壁筛选法,可从人脐带血分离、纯化内皮祖细胞;内皮祖细胞可诱导分化为内皮细胞,增殖和迁移能力都很强。     

波生坦联合西地那非治疗先天性心脏病合并肺动脉高压患儿的临床疗效及安全性评价

目的：探讨波生坦联合西地那非治疗先天性心脏病合并肺动脉高压患儿的临床疗效及不良反应发生情况。方法：选择2015年1月到2016年1月某院收治的90例先天性心脏病合并肺动脉高压患儿,随机分为对照组和试验组,各45例。对照组患儿给予西地那非治疗,试验组患儿给予波生坦联合西地那非治疗,两组患儿均治疗3个月。评价并比较两组患儿的临床疗效。检测并比较两组患儿治疗前后WHO肺动脉高压功能分级。采用右心导管检测测量并比较两组患儿治疗前后平均肺动脉压（mPAP）和肺血管阻力（PVR）。观察并比较两组患儿治疗期间不良反应的发生情况。结果：治疗后,试验组患儿的总有效率为95.56%,明显高于对照组患儿的73.33%,差异具有统计学意义（χ²=8.46,P=0.003 6）。治疗前,两组WHO肺动脉高压功能分级比较差异无统计学意义（P>0.05）;治疗后,两组WHO肺动脉高压功能Ⅱ级患儿均明显多于治疗前,WHO肺动脉高压功能Ⅲ级、Ⅳ级患儿均明显少于治疗前,差异均具有统计学意义（P<0.05）,同时试验组WHO肺动脉高压功能Ⅱ级患儿均明显多于对照组,WHO肺动脉高压功能Ⅲ级、Ⅳ级患儿均明显少于对照组,差异均具有统计学意义（P<0.05）。治疗前,两组患儿的mPAP、PVR比较,差异均无统计学意义（P>0.05）;治疗后,两组患儿的mPAP、PVR均明显小于治疗前,并且试验组患儿的mPAP、PVR均明显小于对照组,差异均具有统计学意义（P<0.05）。治疗期间,两组患儿的不良反应发生率比较,差异无统计学意义（χ²=1.01,P=0.908）。结论：波生坦联合西地那非治疗先天性心脏病合并肺动脉高压患儿临床疗效显著,且安全性较好,值得在临床上推广应用。     

枝化状聚乙二醇交联改善猪去细胞主动脉瓣的力学性能比较

目的 采用不同相对分子质量枝化状聚乙二醇(PEG)交联巯基化的猪去细胞瓣,观察其对去细胞瓣膜力学性能的影响.方法 将25例猪去细胞主动脉瓣随机分为5组:PEG3400组、PEG8000组、PEG12000组、PEG20000组和对照组,常温反应时间4 h.测定残余巯基计算交联效率;静态拉伸实验测定力学性能.结果 4 h交联率依次为92.40%、89.88%、87.87%和87.46%,相对分子质量越小,交联效率越高,PEG3400组与其他各组比较,差异有统计学意义(P＜0.05);力学测试显示,相对分子质量越大,力学强度越高,呈一定的正相关,PEG12000和PEG20000组抗拉强度分别为(3.22±0.41)MPa和(3.19±0.15)MPa,与对照组比较,差异有统计学意义(P＜0.05).结论 相对分子质量12000 Da和20000 Da枝化状聚乙二醇交联可有效改善猪去细胞瓣的力学性能,有望用于构建新型复合的组织工程瓣膜支架材料的研究应用.

Abstract：

Objective Branched polyethylene glycols (PEG) with different molecular weight were cross-linked to the porcine decellularized aortic valve (DAV) and the effects of PEG cross-linking on the mechanical properties were investigated. Methods A total of 25 porcine DAVs were randomly assigned into 5 groups: PEG3400, PEG8000, PEG12000, PEG20000 and control. The reactive time was 4 h at room temperature. The efficiency of crosslinking was calculated by measuring the residual thiol group. The mechanical properties were obtained by static tensile test. Results The efficiency of crosslinking was 92. 40% , 89. 88% , 87. 87% and 87. 46% in PEG3400, PEG8000, PEG12000, PEG20000 groups, respectively. As compared with other groups, the PEG3400 group had significantly greater increase in the crosslinking degree (P ＜ 0. 05). Tensile test showed the tensile strength of PEG12000 and PEG20000 groups was (3. 22 ±0.41) and (3. 19 ±0. 15) MPa, respectively, and significantly different from that in control group (P ＜ 0. 05). The tensile strength and young' s modulus had a positive correlation with the molecular weight of PEG. Conclusion Branched PEG with the molecular weight of 12 000 Da and 20 000 Dacan effectively crosslink to the porcine decellularized aortic valves and improve their mechanical behaviors, and has the potential to be used as the material of fabricating new hybrid scaffold of tissue engineering heart valves.     

枝化状聚乙二醇对牛跟腱Ⅰ型胶原结构与构象稳定性的影响

目的 观察枝化状聚乙二醇对牛跟腱Ⅰ型胶原结构与构象稳定性的影响.方法 以牛跟腱Ⅰ型胶原为原料,以枝化状聚乙二醇为交联剂,在有效交联的前提下,通过测定羟脯氨酸含量观察聚乙二醇交联对胶原酶解稳定性的影响,采用示差扫描量热法(DSC)观察胶原热变性温度,采用圆二色光谱法(CD)观察聚乙二醇对胶原三螺旋构象稳定性的影响.结果 枝化状聚乙二醇交联组24 h降解率为26.79%,而对照组则达97.39%,两者比较差异有统计学意义(P＜0.05).交联组热变性温度为(79.1±1.2)℃,与对照组(68.6±1.9)℃比较,差异有统计学意义(P＜0.05);CD谱测定特征性吸收峰差异无统计学意义(P＞0.05).结论 枝化状聚乙二醇可显著提高其热变形温度和抗酶性分解能力,而对其三螺旋结构与构象无明显不利影响,是较理想的生物高分子交联剂,可有望用于胶原分子的交联改性.

Abstract：

Objective The triple helix of collagen is the basis of its biological function, such as cell adhesion and tissue remodeling. Crosslinking of collagen with chemical agent will improve the biomechanical properties. However, the effects of differernt crosslinking agents on the structure and conformation stability of type Ⅰ collagen are rarely investigated. Methods The branched polyethylene glycol ( PEG)derivative ( MW 12 kD) was used as crosslinking agent, and allowed to react with bovine achilles' s tendon type Ⅰ collagen modified by succinimidylacetylthioacetate (SATA). The ability of resistance of crosslinked collagen to enzymatic degradation was investigated by measuring the release of hydroxyproline, and differential scanning calorimeter ( DSC ) was taken to determine the thermal denaturation temperature. The effect of PEG on the riple helix of collagen was studied by circular dichroism ( CD) . Results The resistance ability of PEG crosslinked collagen was strongly enhanced when compared with that of control group ( P ＜0. 05 ) , and the thermal denaturation temperature was also significantly rised. CD demonstrated that PEG crosslinking did not result in the destruction of the triple helix conformation of type Ⅰ collagen. Conclusion Branched PEG derivative used in this study is a promising polymer crosslinking agent that may be utilized in the modification of type Ⅰ collagen.     

基质金属蛋白酶-2敏感型聚乙二醇复合水凝胶的制备及性质

目的 采用相对分子质量20000 Da分枝状聚乙二醇(four-armed PEG-Ac)和基质金属蛋白酶-2(MMP-2)敏感型底物肽制备一种可降解复合水凝胶,并检测其性能.方法 以制备浓度为10％ (w/v)的酶敏感型复合PEG水凝胶为实验A组,单纯PEG水凝胶为对照B组,比较两种水凝胶在37℃磷酸盐缓冲液(PBS)和血清的降解,并检测细胞毒性.在制胶过程中包埋转化生长因子(TGF-β1),观察两组水凝胶对TGF-β1的缓释效果.结果 PBS中A、B两组4周累计降解率分别为78.36％、76.28％,两者差异无统计学意义(P＞0.05)；分别添加正常人体血清,A组4周累计降解率为88.35％,降解速度加快,B组则变化不明显.噻唑蓝(MTT)比色法检测复合PEG水凝胶无细胞毒性.A、B两组水凝胶TGF-β17 d累计释放率分别为50.63％、44.36％,两者差异无统计学意义(P＞0.05),分别添加MMP-2后,A组对TGF-β1的释放速度明显加快.结论 MMP-2敏感型PEG水凝胶结构稳定,对细胞无毒性,包埋TGF-β1有良好的控释效果,有望应用于新型组织工程心脏瓣膜支架材料的研制.     

枝化状聚乙二醇交联改善猪去细胞主动脉瓣的力学性能比较

Objective Branched polyethylene glycols (PEG) with different molecular weight were cross-linked to the porcine decellularized aortic valve (DAV) and the effects of PEG cross-linking on the mechanical properties were investigated. Methods A total of 25 porcine DAVs were randomly assigned into 5 groups: PEG3400, PEG8000, PEG12000, PEG20000 and control. The reactive time was 4 h at room temperature. The efficiency of crosslinking was calculated by measuring the residual thiol group. The mechanical properties were obtained by static tensile test. Results The efficiency of crosslinking was 92. 40% , 89. 88% , 87. 87% and 87. 46% in PEG3400, PEG8000, PEG12000, PEG20000 groups, respectively. As compared with other groups, the PEG3400 group had significantly greater increase in the crosslinking degree (P ＜ 0. 05). Tensile test showed the tensile strength of PEG12000 and PEG20000 groups was (3. 22 ±0.41) and (3. 19 ±0. 15) MPa, respectively, and significantly different from that in control group (P ＜ 0. 05). The tensile strength and young' s modulus had a positive correlation with the molecular weight of PEG. Conclusion Branched PEG with the molecular weight of 12 000 Da and 20 000 Dacan effectively crosslink to the porcine decellularized aortic valves and improve their mechanical behaviors, and has the potential to be used as the material of fabricating new hybrid scaffold of tissue engineering heart valves.     

单操作孔与全胸腔镜在小儿纵膈肿瘤手术中的应用比较

目的探讨单操作孔手术与全胸腔镜手术在小儿纵膈肿瘤治疗中的效果。 方法回顾性分析2014年1月至2017年6月武汉市儿童医院心胸外科收治的46例纵膈肿瘤患儿临床资料。根据手术方式不同将患儿分为2组,A组为全胸腔镜手术组,共29例患儿;B组为单操作孔手术组,共17例患儿,2组患儿年龄、体质量、肿瘤大小、类型等差异无统计学意义。分析比较2组患儿手术时间、术中出血量、胸腔引流时间、手术后住院时间和手术后并发症等。 结果46例患儿均顺利完成手术,A组中转开胸2例,B组无中转开胸,术后5例带气管插管回ICU。A组平均手术时间（69.35±8.24）min,较B组平均手术时间［（72.80±6.28）min］短,差异具有统计学意义（P<0.05）,术中出血量2组间比较［（21.47±6.85）ml vs（27.52±4.15）ml］差异无统计学意义;A组患儿平均胸腔引流时间、手术后住院时间较B组略长,分别为（5.46±1.72）d vs （4.68±1.39）d,（6.93±1.34）d vs（5.92±1.67）d。2组患儿术后均无严重并发症,恢复顺利。 结论与全胸腔镜手术相比,单操作孔手术治疗小儿纵隔肿瘤,具有创伤小、恢复快等优点,但手术耗时较长。