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find Keyword "polymer" 66 results
  • Expressive varieties of Nogo-A mRNA in injured optic nerves

    Objective To evaluate the expressive varieties of Nogo-A mRNA in injured optic nerves of rats. Methods Reverse transcription polymerase chain reaction (RT-PCR) method was used to hemi-quantitatively analyze the levels of Nogo-A mRNA in the optic nerves 3, 7, 9, 15, 21, and 25 days respectively after injury.Results The level of the expression of Nogo-A mRNA was low in the normal optic nerves, while it was significantly high in the optic nerves 3 days after in jury, and kept the high level still after 25 days.Conclusion The expression of Nogo-A mRNA in injured optic nerves is increased. (Chin J Ocul Fundus Dis,2003,19:201-268)

    Release date:2016-09-02 06:00 Export PDF Favorites Scan
  • A STUDY ON THE GENOMIC VARIANT IN MATCHED ADENOCINOMA AND NON-TUMOR GASTRIC TISSUE BY ARBITRARILY PRIMER POLYMERASE CHAIN REACTION

    Objective To identify and isolate the variant gene associated with gastric adenocarcinoma and clone the fragment of variant gene.Methods By arbitrarily primer polymerase chain reaction (AP-PCR), DNA samples from 5 matched gastric adenocarcinoma and non-tumor gastric tissues were analysed. Results The produced AP-PCR profiles were different in each matched gastric adenocarcinoma and non-tumor gastric tissue. One differentiated amplified DNA fragments PW2.2 from a matched gastric adenocarcinoma were cloned. The result of Southern blot hybridization with PW2.2 as a probe showing that this fragment was also found in some other gastric adenocarcinoma samples. Conclusion AP-PCR fingerprinting assay can be used to identify and clone the variant genes associated with gastric adenocarcinoma.

    Release date:2016-09-08 02:00 Export PDF Favorites Scan
  • Decellularized Xenogenic Valve Scaffolds Coated with Biodegradable Polymer for Heart Valve Tissue Engineering

    Objective To study and test novel hybrid valves in vitro and in vivo, and provide basis for clinical use in future. Methods The hybrid valves were fabricated from decellularized porcine aortic valves coated with poly (3-hydroxybutyrate-co-3hydroxyhexanoate, PHBHHx).(1)In the mechanical test in vitro, the uniaxial tensile biomechanics test of the fresh (n=12), uncoated (n=12) and hybrid valve leaflets (n=12) were investigated. (2)In study in vivo, hybrid valves(n=5) implanted in pulmonary position in sheep without cardiopulmonary bypass. Uncoated grafts (n=5) used as control. The specimens of the hybrid or uncoated valve in sheep were explanted and examined by scanning electron microscopy, histology, calcium content and immunofluorescence staining 18 weeks after surgery. Results The mechanical test in vitro revealed that coating with PHBHHx increased maximal tensile strength of hybrid valves compared with the fresh and uncoated state (P<0.05). The results in vivo indicated the hybrid valves maintained original shape and softness. Immunofluorescence staining for CD31 confirmed that the surface of hybrid valve was covered by confluent CD31+ cells.The interstitium of hybrid valve indicated that smooth muscle actin (SMA)+ cells population were similar to native valvular tissue. The calcium content of hybrid valve was significantly lower than that of uncoated valve leaflets (P<0.05). Conclusion Decellularized porcine aortic valves coated with PHBHHx have good biological and biomechanical characteristics. The hybrid valve may provide superior valve replacement with current techniques.

    Release date:2016-08-30 06:09 Export PDF Favorites Scan
  • RESEARCH AND APPLICATION OF DRUG CONTROLLED RELEASE TECHNIQUE IN TISSUE ENGINEERING

    OBJECTIVE: To investigate protection of biological activity and controlled release of growth factor by means of drug controlled release technique in tissue engineering. METHODS: Using drug controlled release technique that to embed or microcapsulate the biological drug with biodegradable polymer. RESULTS: The aliphatic polylactone could be used as drug carrier for each drug including the biological matter. And the release behavior of the drug could be controlled by adjusting the molecular structure of the carrier and the controlled release method. The successful example, that to realize regeneration of rat’s sciatic nerve with 5, 10, 15 and 20 mm of gap by using polylactide as nerve guide and the embedding growth factor, had been obtained. CONCLUSION: It is possible to realize protection of biological activity and sustained release of growth factor by using aliphatic polylactone as drug carrier.

    Release date:2016-09-01 10:21 Export PDF Favorites Scan
  • hVEGF165/pcDNA3. 1 Expression in Neonate Mice Myocardial Cells

    Objective To investigate the transfection and expression of recombinant plasmid human vascular endothelial growth factor 165/pcDNA3. 1 (hVEGF165/pcDNA3. 1) in myocardial cells, and to build foundation for gene therapy and cell therapy of coronary artery disease (CAD). Methods Myocardial cells were cultured in vitro and transfected by hVEGF165/pcDNA3.1 with liposome; then transient expressed protein was detected by reverse transcriptase-polymerase chain reaction (RT-PCR), immunochemistry and Western blotting. Results A strap as hVEGF165 was obtained by RT-PCR, the protein of hVEGF165 was found in myocardial cells by immunochemistry and in supernatant by Western blotting. Conclusion The recombinant plasmid hVEGFI65/pcDNA3. 1 can be expressed in myocardial cells, and may be used in studying CAD by gene therapy and cell transplantation.

    Release date:2016-08-30 06:22 Export PDF Favorites Scan
  • PROGRESS AND PROSPECT OF SYNTHETIC BIODEGRADABLE POLYMERS FOR BONE REPAIR AND RECONSTRUCTION

    Objective To review the latest researches of synthetic biodegradable polymers for bone repair and reconstruction, to predict the progress of bone substitute materials and bone tissue engineering scaffolds in future. Methods The l iterature concerning synthetic biodegradable polymers as bone substitute materials or bone tissue engineering scaffolds was collected and discussed. Results Al i phatic polyester, polyanhydride, polyurethane and poly (amino acids) were the most extensively studied synthetic biodegradable polymers as bone substitutes and the scaffolds. Each polymer was of good biological safety and biocompatibil ity, and the degradation products were nontoxic to human body. The mechanical properties and degradation rate of the polymers could be adjusted by the type or number of the monomers anddifferent synthetic methods. Therefore, the polymers with suitable mechanical strength and degradation rate could be produced according to the different requirements for bone grafting. Prel iminary studies in vivo showed their favorable capacity for bone repair. Conclusion The synthetic biodegradable polymers, especially the copolymers, composite materials and those carrying bone growth factors are expected to be the most promising and ideal biomaterials for bone repair and reconstruction.

    Release date:2016-08-31 05:47 Export PDF Favorites Scan
  • Expression of CK20 mRNA in Blood of Patients with Colorectal Cancer

    ObjectiveTo investigate the clinical significance of CK20 mRNA expression in blood of patients with colorectal cancer. MethodsThe expressions of CK20 mRNA in blood of twenty healthy volunteers, ten patients with colorectal polyp and sixtyone patients with colorectal cancer were detected by RT-PCR. ResultsThe positive rate of CK20 mRNA in peripheral venous blood and portal venous blood of patients with colorectal cancer were 41.0%(25/61) and 45.9%(28/61), which was not significantly different (Pgt;0.05). The expression of CK20 mRNA in patients with colorectal cancer was associated with clinical TNM stage of tumor, local lymph node metastasis, distance metastasis, and the depth of invasion (Plt;0.05). No expression of CK20 mRNA was detected in blood of twenty healthy volunteer’s and ten patients with colorectal polyp. ConclusionCK20 is a specific marker for detecting blood micrometastasis of colorectal cancer. The expression of CK20 mRNA in blood of patients with colorectal cancer is related with TNM stage, invasion, and metastasis of colorectal cancer.

    Release date:2016-09-08 10:45 Export PDF Favorites Scan
  • Effects of Gefitinib on Expression of Epidermal Growth Factor Receptor in Bile Duct Epithelial Cells and Its Significance

    Objective To observe the effect of gefitinib on expression of epidermal growth factor receptor (EGFR) in bile duct epithelial cells, and the feasibility of inhibiting hyperplasia of bile duct epithelial cells with gefitinib. Methods Sixty-one patients with hepatolithiasis having to be in hospital for surgery from the First People’s Hospital of Shuangliu county were selected, with 25-65 years old, average 46.92 years. The patients were randomly divided into therapy group and control group. There were 30 cases in therapy group, in which fine duct was placed on lesion bile duct during operation, and through whom gefitinib solution was perfused after operation. There were 31 cases in control group with only T tube drainage after operation. The bile duct sample was obtained respectively during the operation and 6 weeks and 12 weeks after operation. The histology and expression change of EGFR were observed by HE staining, immunohistochemistry and RT-PCR method respectively. Results There were no significant differences in pathohistology changes of bile duct and the EGFR protein and mRNA expression between therapy group and control group during operation. The hyperplasia of epithelium mucosae and submucosal gland in the therapy group were obviously decreased as compared with those in control group, the EGFR mRNA and protein expression in therapy group were weaker than those of control group (Plt;0.05) 6 weeks and 12 weeks after gefitinib treatment. Conclusion EGFR is overexpressed in the chronic proliferative cholangitis, and continuously local application of gefitinib after operation can specifically interrupt the activation and expression of EFGR and then effectively inhibit the hyperplasia of bile duct epithelial cells.

    Release date:2016-09-08 10:54 Export PDF Favorites Scan
  • DETERMINATION OF FIBRONECTIN mRNA EXPRESSION IN PATIENTS WITH DIABETIC ULCERS BY QUANTITATIVE POLYMERASE CHAIN REACTION TECHNIQUE

    OBJECTIVE To determine the characteristics and regularity of fibronectin mRNA expression in diabetic ulcers, and to investigate the relationship between the changes of fibronectin mRNA expression and pathogenesis of diabetic ulcer. METHODS Biopsies were removed from the margins of diabetic foot ulcers, included surrounding skin as experimental group, and the biopsies from normal skin of the same patients as control group. The mRNA expression of fibronectin was measured by quantitative RT-PCR technique. RESULTS The mRNA expression of fibronectin could be detected in both normal skin and diabetic foot ulcers, but the level of expression in diabetic ulcers was lower than that of normal skin. CONCLUSION The level of mRNA expression of fibronectin in diabetic ulcers is decreased, which suggest that the down-regulation of transcription may be one of the mechanisms of chronic impaired ulcers.

    Release date:2016-09-01 10:25 Export PDF Favorites Scan
  • Experimental Study on Changes of Expression of AFP mRNA in Human Hepatocellular Carcinoma Tissues after Oral Xeloda Therapy

    【Abstract】Objective To explore the changes of expression of AFP mRNA in human hepatocellular carcinoma (HCC) tissues after oral Xeloda therapy.Methods Total RNA was extracted from HCC tissue samples collect after operation and nested reverse transcription polymerase chain reaction (RT-nested PCR) assay was performed to determine the expression of AFP mRNA in this study.Results The final product of AFP mRNA amplified by RT-PCR was 174 bp and by RT-nested PCR was 101 bp. The AFP mRNA is positive in 12 of 21 patients (positive rate 57.14%) amplified by RT-nested PCR assay in Xeloda treatment group which is much lower than control group: 18 of 20 patients (positive rate 90.00%),P<0.05.The serum AFP value of Xeloda treatment group 〔(23.2±12.8) μg/L〕 is much lower than that of control group 〔(39.6±24.3) μg/L〕 four weeks after operation (P<0.05). However, There was no difference between two groups in serum AFP value before operation.Conclusion Xeloda can effectively suppress the expression of AFP mRNA in human HCC tissues and lower it’s product serum AFP value.The clinical application of Xeloda in HCC patients deserve further study.

    Release date:2016-08-28 04:44 Export PDF Favorites Scan
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