目的 合成可生物降解的基因载体，并分析其生物毒性及转染率。 方法 低分子量聚乙烯亚胺（PEI）通过双硫键交联合成可降解的高分子量PEI衍生物（SS-PEI），通过红外光谱和核磁波谱分析技术分析其化学结构，采用细胞活力实验和检测大鼠肝肾功能指标分析其细胞和体内毒性，并转染羟基荧光素修饰的siRNA（FAM-siRNA）分析细胞转染率。 结果 红外波谱和核磁波谱分析可见酰胺键的特征波谱，噻唑蓝法和肝肾功能指标显示SS-PEI不同剂量组与对照组的差异均无统计学意义（P＞0.05），SS-PEI/FAM-siRNA转染率为（76.0 ± 2.8）%。 结论 SS-PEI的合成可明显提高装载siRNA的效率，具有安全、高效等特点。
ObjectiveTo summarize the method and experience in surgical treatment for mesh infection after prosthetic patch repair of ventral hernia. MethodsThe clinical data of 16 patients with mesh infection after ventral hernia repair accepted surgical treatment in our department from June 2007 to May 2010 were analyzed retrospectively. There were 10 males and 6 females, the age range from 24 to 73 years with an average 45.2 years. The patients with mesh infection included 11 cases of infection after incisional hernia repair, 4 cases of infection after abdominal wall defects repair caused by abdominal wall tumor resection, 1 mesh infection combine with urinary fistula caused by parastomal hernia of ileal neobladder repaired by using prosthetic patch. Clinical manifestation included mesh exposion, abscess, chronic sinus, and enterocutaneous fistula. All patients accepted local treatment of change dressing by primary operative surgeon, but the wounds didn’t heal about 3 to 24 months. Then the patients performed radical removal of infected mesh and abdominal wall reconstruction. ResultsAll patients accepted affected mesh removal successfully. Five patients performed abdominal wall reconstruction by using components separation technique. Four cases accepted abdominal wall repair by using polypropylene mesh. Five patients performed abdominal wall repair by using human acelluar dermal matrix. One case accepted change dressing and vacuum aspiration on the infected wound surface without reconstruction. And one case closed the wound immediately after infected mesh removal. The postoperative hospitalization time was 9 to 25 d (average 14 d). Thirteen patients recovered with primary wound healing. The other 3 cases recovered with second healing by local change dressing. All patients were followed up from 6 to 34 months (average 22 months), no abdominal wall hernia recurrence occurred. ConclusionsIt is very difficult to deal with mesh infection after prosthetic patch repair of abdominal wall hernia or defect. The surgical treatment should be done according to specific condition of each individual so as to acquire satisfied results.
ObjectiveTo understand the effect of nitric oxide (NO) on the formation of hyperdynamic circulatory syndrome (HCS) and the influence of level of NO on HCS. MethodsAfter establishment of stable HCS in partial portal vein ligated rats,the quantity of NO in blood of portal vein and the activity of nitric oxide synthase (NOS) in liver were determined by pre and post injection of inhabitor of NOS (NGmethylLarginine) and hemodynamics was supervised simultaneously.ResultsThe quantity of NO was paralleled with the activity of NOS and was elevated markedly by 24 hours after operation and reached the top by 48 hours after surgery. These sequential changes were coincided with the dilation of general vascularture. There was a close relation between this changes and the formation of HCS.The quantity of NO and the activity of NOS were decreased significantly to the level of the control group after injection of NGmethylLarginine (LNMMA). LNMMA inhabited the activity of NOS and blocked the production of NO. HCS ameliorated obviously. ConclusionNO plays an important role in initiating the dilation of general vascularture and plays a critical role in the formation of HCS. HCS will be ameliorated obviously or be blocked completely by eliminating the effect of NO and the portal pressure will decreased significantly or recover to normal range.
Test of tissue tolerance to domastic prosthetic materials (carbon fiber mesh, siliconized velvet, silk cloth and dacron cloth) as a subcutaneos transplant was performed in the adcominal wall of rabbit. These implants and their surroundding tissues were excied for studies at second , fourth, eighth and the twelfth weeks after operation. Ratio of fibroblast count to inflammatory cells count which is a common parameter of tissue tolerance was calculated in these four groups. The result shows that fibroblastic cell reaction elicited by carbon fiber mesh is the greates among the four prosthetic materials, the second one is dasron cloth. The inflammatory cell reaction elicited by silk is the greatest among the four materials, the second is carbon fiber mesh, and the dacron cloth the least. Tissure tolerance of dacron cloth is the best in the four prosthetic materials for implantation while sick is the worst.
Objectives To investigate the frequency of LTC4S A-444C polymorphism in Chinese Han population in Beijing and to evaluate its association with susceptibility to asthma，asthma severity and clinical response to leukotriene receptor antagonist.Methods The LTC4S A-444C polymorphism was analyzed in 101 patients with asthma and 105 healthy controls.Then 18 asthmatics were recruited，and a 2-week prospective，open trial of montelukast was performed in addition to the previous medications.Results In the asthma group，the frequencies of A and C allele at -444 locus of LTC4S gene were 81.0% and 19.0%，respectively，and genotype frequencies of AA，AC and CC were 65.4%，30.5% and 3.8%，respectively.There was no significant difference in LTC4S A-444C polymorphism between the asthmatics and healthy controls（Pgt;0.05）.The asthmatics with the C-444 allele had significantly lower forced expiratory volume in one second（FEV1） than wild-type A homozygotes [（58.6±21.6）% predicted vs （70.3±22.4）% predicted，Plt;0.05）].A correlation was observed between the variant C-444 allele and asthma severity（Plt;0.05）.After administered montelukast 1 week，the A-444 allele homozygotes（n=9） responded better than the C（-444） allele carriers（n=7）[（10.8±10.2）% vs （–9.8±16.2）% improvement of FEV1，Plt;0.05].After 2 weeks，the A-444 allele hemozygotes also responded better，although there was no statistical difference（Pgt;0.05）.Conclusion In Chinese Han population LTC4S A-444C polymorphism is associated with asthma severity and probably contributes to the clinical response to leukotriene receptor antagonists.
Objective To investigate the effects of simvastatin on the collagen synthesis of rat pulmonary arterial smooth muscle cells ( PASMCs ) induced by hypoxia. Methods Under hypoxic condition, rat PASMCs were cultured with different concentrations of simvastatin. Collagen synthesis of PASMCs with or without simvastatin were measured by 3H-proline incorporation assay. The mRNA expression of TGF-β1 and the contents of super oxide dismrtase ( SOD) ,malondialdehyde ( MDA) in mediumwere also measured. Results The incorporation data of 3H-TdR in the hypoxia group was significantly increased as compared with that in the control group ( P lt;0. 01) , and simvastatin significantly reduced the incorporation data of 3H-TdR induced by hypoxia. The expression of TGF-β1 mRNA in the hypoxia group was significantly increased as compared with that in the control group ( P lt; 0. 01 ) , and simvastatin could significantly inhibited hypoxia-induced expression of TGF-β1 mRNA in a dose-dependent manner. Compared with the hypoxia group, the expression of TGF-β1 mRNA decreased by 55% in simvastatin( 10 - 6mol /L) group ( P lt; 0. 01) , and by 70% ( P lt; 0. 01) in simvastatin ( 10 - 5mol /L) group. Compared with the control group, the activity of SOD was reduced and the contents of MDA were increased significantly in the hypoxia group. Simvastatin can increase the activity of SOD and reduced the content of MDA in a dose-dependent manner. Conclusions Simvastatin can decreases collagen synthesis of PASMCs. This effect might be explained that simvastatin can reduce lipid peroxide and expression of TGF-β1 mRNA.
Objective To explore the induction of cardiomyogenesis of microRNA-129 （mir-129） in rat bone marrowmesenchymal stem cells （BM-MSCs） and its mechanism. Methods BM-MSCs were isolated from Sprague-Dawley rats and cultured in vitro. Overexpression of mir-129 or both mir-129 and glycogen synthase kinase-3β （GSK-3β） in BM-MSCs was produced with a lentiviral vector system. All the BM-MSCs were divided into four groups: control group （MSCs），Lentiviral vectors＋MSCs group （Lv-MSCs），mir-129 transfection group （mir-129-MSCs），and mir-129＋GSK-3βdouble transfection group （mir-129＋GSK-3β-MSCs）. Five-Azacytidine （5-Aza） （10 μmol/L） was used to induce BM-MSCsdifferentiation into cardiomyocytes. On the 1st，5 th，10 th，15 th and 20 th day after induction，realtime-PCR was performedto detect mRNA levels of GATA-4，Nkx2.5 and MEF-2C. On the 10 th，15 th and 20 th day after induction，Western blottingwas performed to examine expression levels of cTnI，Desmin，GSK-3β，phosphorylated β-catenin and dephosphorylated β-catenin. Results Compared with the control group，at respective time points，mRNA levels of cardiomyogenic genes and expression levels of cardiomyocyte-related proteins of mir-129 transfection group were significantly elevated，theexpression level of GSK-3β was significantly decreased，and the ratio of dephosphorylated/phosphorylated β-catenin was significantly elevated. When both mir-129 and GSK-3β were overexpressed in BM-MSCs，mRNA levels of cardiomyogenicgenes and expression levels of cardiomyocyte-related proteins were significantly lower than those of mir-129 transfection group，and the ratio of dephosphorylated/phosphorylated β-catenin was significantly decreased. Conclusion Overexpression of mir-129 can promote cardiomyogenesis of rat BM-MSCs possibly via inhibiting GSK-3β production and thus decreasing the inhibition of phosphorylation of β-catenin which then enters the nucleus and activates downstream signaling pathways that regulate cardiomyogenic differentiation of BM-MSCs.
The establishing of myocardial tissue engineering techniques not only solve a series of issues that generate in cell and tissue transplantation after myocardial infarction, but also create a platform for selecting better materials and transplantation techniques. However, both experimental animal studies and recent clinical trials indicate that current transplantation techniques still have many defects, mainly including lack of suitable seed cells, low survival rate and low differentiation rate after transplantation. In this context, extracellular matrix （ECM）, as myocardial tissue engineering scaffold materials, has gained increasing attention and become a frontier and focus of medical research in recent years. ECM is no longer merely regarded as a scaffold or a tissue, but plays an important role in providing essential signals to influence major intracellular pathways such as cell proliferation, differentiation and metabolism. The involved models of ECM can be classified into following types：natural biological scaffold materials, synthetic polymer scaffold materials and composite scaffold materials with more balanced physical and biological properties. This review mainly introduces research progress of ECM in myocardial tissue engineering and ECM materials.