Human telomerase reverse transcriptase（hTERT） activity was detected in human nasopharyngeal carcinoma celI（CNE） but not in human normal lung fibroblas t（CCD-11Lu）. Recombinant adenoviruses Ad-CMV-TK-enh and Ad-h...Human telomerase reverse transcriptase（hTERT） activity was detected in human nasopharyngeal carcinoma celI（CNE） but not in human normal lung fibroblas t（CCD-11Lu）. Recombinant adenoviruses Ad-CMV-TK-enh and Ad-hTERT-TK-enh were constructed and infected into normal fibroblasts and nasopharyngeal carcinoma cells. Ad-CMV-TK-enh with 100 μmol/L of ganciclovir（GCV） caused 87% of CCD-11Lu cells death and 91% of CNE cells death, Ad-hTERT-TK-enh with 100 μmol/L of GCV caused 24% of CCD-11Lu cells death and 79% of CNE cells death. These results indicate that the Ad-hTERT-TK-enh with GCV may be a useful method in suppressing tumor growth in targeted nasopharyngeal carcinoma gene therapy.展开更多
Located at the carboxyl terminal of the human papillomavirus major capsid protein L1, helix-5（h5） is cru-cial to L1 folding and pentamer formation. Site-directed mutagenesis of the leucine residue on site 469 into l...Located at the carboxyl terminal of the human papillomavirus major capsid protein L1, helix-5（h5） is cru-cial to L1 folding and pentamer formation. Site-directed mutagenesis of the leucine residue on site 469 into lysine, alanine, serine and glycine was performed to explore the effect of the resultant mutations on L 1 pentamer formation. The soluble yields of the L1 pentamers of the L469A and L469K mutants were nearly two fold higher than that of the wild type. Molecular dynamics simulation was then performed to reveal the intrinsic mechanisms involved in the improvement of L 1 pentamer yield. Accordingly, the secondary structures of h5, β-G2, β-B1, β-C, β-D, and β-F were altered. The altered structures improved the hydrophobic interaction between h5 and fl-core ＂jelly＂ and the stability of h5. The hydrophobic surface area of residue 469 was reduced by 50% relative to that of the wild type. The C--O group of residue 469 and C--N group of L470 were both exposed to the solvent in the L469A mutant. These modifications may account for the increased solubility and stability and the promotion of pentamer formation induced by the point mutation. Therefore, the changes in the hydrophobic properties of h5 and the core structure determined the pentamer formation and solubility. This study may assist the development of a cost-effective platform for the production of prophylactic virus-like particle vaccines.展开更多
To study the conservative life of the artificial mechanical heart valve holder,CATIA software was used for modeling,and ABAQUS finite element analysis was used to analyze the stress of the valve holder in the complex ...To study the conservative life of the artificial mechanical heart valve holder,CATIA software was used for modeling,and ABAQUS finite element analysis was used to analyze the stress of the valve holder in the complex environment of the human body and the residual thermal stress during production and processing.The damage tolerance method based on fracture mechanics analyzes the maximum initial crack size that the heart valve holder can tolerate under the premise that the structural safety life is longer than the life of the implanted patient.The results show that the maximum initial crack size is only tens of microns;the traditional S/N life analysis can only obtain non-conservative life,and the damage tolerance method is the basic requirement for analyzing the life and quality control of artificial mechanical heart valves.展开更多
The preferred orientation of pyrolytic carbon coating is an important performance parameter for the safe use of artificial mechanical heart valve.In this paper,the selected area electron diffraction(SAED)analysis of p...The preferred orientation of pyrolytic carbon coating is an important performance parameter for the safe use of artificial mechanical heart valve.In this paper,the selected area electron diffraction(SAED)analysis of pyrolytic carbon coating samples of artificial heart valve was carried out by transmission electron microscopy(TEM),and the experimental method of characterizing the preferred orientation of pyrolytic carbon by electron diffraction spectrum,namely bacon anisotropy factor(BAF),was described,and the orientation angle and BAF corresponding to the electron diffraction spectrum were measured.The results show that the BAF value can directly reflect the anisotropy of pyrolytic carbon in the selected area.The BAF value range is from 1 to infinity,and the higher the preferred orientation is,the greater the value is.The BAF value decreases exponentially with the increase of orientation angle.When the pyrolytic carbon tends to be isotropic,the orientation angle tends to 180 and the BAF value tends to 1.展开更多
基金Supported in Part by the Agency of Science and Technology of Sichuan Province, China(No.2008JY0020)the National Natural Science Foundation of China(No.30872396).
文摘Human telomerase reverse transcriptase（hTERT） activity was detected in human nasopharyngeal carcinoma celI（CNE） but not in human normal lung fibroblas t（CCD-11Lu）. Recombinant adenoviruses Ad-CMV-TK-enh and Ad-hTERT-TK-enh were constructed and infected into normal fibroblasts and nasopharyngeal carcinoma cells. Ad-CMV-TK-enh with 100 μmol/L of ganciclovir（GCV） caused 87% of CCD-11Lu cells death and 91% of CNE cells death, Ad-hTERT-TK-enh with 100 μmol/L of GCV caused 24% of CCD-11Lu cells death and 79% of CNE cells death. These results indicate that the Ad-hTERT-TK-enh with GCV may be a useful method in suppressing tumor growth in targeted nasopharyngeal carcinoma gene therapy.
基金Supported by the National Natural Science Foundation of China（Nos. 91027027, 21373101 ）.
文摘Located at the carboxyl terminal of the human papillomavirus major capsid protein L1, helix-5（h5） is cru-cial to L1 folding and pentamer formation. Site-directed mutagenesis of the leucine residue on site 469 into lysine, alanine, serine and glycine was performed to explore the effect of the resultant mutations on L 1 pentamer formation. The soluble yields of the L1 pentamers of the L469A and L469K mutants were nearly two fold higher than that of the wild type. Molecular dynamics simulation was then performed to reveal the intrinsic mechanisms involved in the improvement of L 1 pentamer yield. Accordingly, the secondary structures of h5, β-G2, β-B1, β-C, β-D, and β-F were altered. The altered structures improved the hydrophobic interaction between h5 and fl-core ＂jelly＂ and the stability of h5. The hydrophobic surface area of residue 469 was reduced by 50% relative to that of the wild type. The C--O group of residue 469 and C--N group of L470 were both exposed to the solvent in the L469A mutant. These modifications may account for the increased solubility and stability and the promotion of pentamer formation induced by the point mutation. Therefore, the changes in the hydrophobic properties of h5 and the core structure determined the pentamer formation and solubility. This study may assist the development of a cost-effective platform for the production of prophylactic virus-like particle vaccines.
文摘To study the conservative life of the artificial mechanical heart valve holder,CATIA software was used for modeling,and ABAQUS finite element analysis was used to analyze the stress of the valve holder in the complex environment of the human body and the residual thermal stress during production and processing.The damage tolerance method based on fracture mechanics analyzes the maximum initial crack size that the heart valve holder can tolerate under the premise that the structural safety life is longer than the life of the implanted patient.The results show that the maximum initial crack size is only tens of microns;the traditional S/N life analysis can only obtain non-conservative life,and the damage tolerance method is the basic requirement for analyzing the life and quality control of artificial mechanical heart valves.
文摘The preferred orientation of pyrolytic carbon coating is an important performance parameter for the safe use of artificial mechanical heart valve.In this paper,the selected area electron diffraction(SAED)analysis of pyrolytic carbon coating samples of artificial heart valve was carried out by transmission electron microscopy(TEM),and the experimental method of characterizing the preferred orientation of pyrolytic carbon by electron diffraction spectrum,namely bacon anisotropy factor(BAF),was described,and the orientation angle and BAF corresponding to the electron diffraction spectrum were measured.The results show that the BAF value can directly reflect the anisotropy of pyrolytic carbon in the selected area.The BAF value range is from 1 to infinity,and the higher the preferred orientation is,the greater the value is.The BAF value decreases exponentially with the increase of orientation angle.When the pyrolytic carbon tends to be isotropic,the orientation angle tends to 180 and the BAF value tends to 1.
