To prepare a solid dispersion of cisapride with hydroxypropylmethyl cellulose(HPMC E5 LV) as carrier for the purpose of accelerating the in vitro drug release by means ofimproving the solubility of the model drug. Met...To prepare a solid dispersion of cisapride with hydroxypropylmethyl cellulose(HPMC E5 LV) as carrier for the purpose of accelerating the in vitro drug release by means ofimproving the solubility of the model drug. Methods Alcohol and simulated gastric fluid (SGF) wereused to dissolve cisapride and HPMC in order to make the model drug dispersed homogeneously in thecarrier. The HPMC-cisapride solid dispersion was then obtained by conventional solvent evaporationmethod. Powder X-ray diffraction (XRD) was used to measure the diffraction peaks of pure carrier,pure cisapride, physical mixture of HPMC with cisapride (4:1), and HPMC-cisapride solid dispersion(4:1) to confirm the crystal existence. The solubility of pure drug and HPMC-cisapride soliddispersion was measured with water, SGF and simulated intestinal fluid (SIF) . The in vitro drugreleases of the sustained release tablet prepared with pure cisapride or HPMC-cisapride soliddispersion were investigated with water and SGF as media, respectively. Results No diffraction peakswere found by X-ray diffraction in the HPMC-cisapride solid dispersion (4:1), indicating that thedrug existed in an amorphous form at that drug-carrier ratio. Compared with the pure drug, thesolubilities of HPMC-cisapride solid dispersion are increased by 239.4% in SGF, 132.6% in water, and117.9% in SIF. According to the in vitro drug release, the sustained release tablet prepared withHPMC-cisapride solid dispersion had a faster drug release than did that prepared with pure drug. Thein vitro drug release profiles were found to comply with Higuchi's rule. Conclusion The in vitrodrug release of the sustained release tablet made by HPMC-cisapride solid dispersion is improvedowing to the increased drug solubility.展开更多
In order to find out the influence of the instability of angular velocity of the rotating carrier itself on the stability of silicon micromachined gyroscope, the digital models for relative error of the high and low d...In order to find out the influence of the instability of angular velocity of the rotating carrier itself on the stability of silicon micromachined gyroscope, the digital models for relative error of the high and low damping gyroscope's output signal are given respectively, based on the motion equations of the silicon micromachined gyroscope. Theory proves that the output signal error of the silicon micromachined sensor is mainly caused by the instability of damping factor and the angular velocity of the rotating carrier itself. The experiment result indicates that the error of proportionality coefficient of output voltage which is caused by the instability of the angular velocity of the rotating carrier itself reaches to 4.1 %. Theoretical demonstration and experimental verification show that the instability of angular velocity of the rotating carrier itself has an important effect on the stability of low damping silicon micromachined gyroscope.展开更多
By combining coral with recombinant human bone morphogenetic protein-2 (rhBMP-2), rhBMP-2/coral composite was obtained in this study. Following implantation of the composite into the muscle pouches of mice, cartilage ...By combining coral with recombinant human bone morphogenetic protein-2 (rhBMP-2), rhBMP-2/coral composite was obtained in this study. Following implantation of the composite into the muscle pouches of mice, cartilage growth was induced in the pores or on the surface of the implants at one week, woven bone at three week and lamellar bone with bone marrow at six week, and coral was absorbed partially. The induced formation of endochondral bone was time-related and rhBMP-2 dose-related. The results of this study indicate that the composite possesses a superior ability of osteogenesis, and coral acts as one of the most suitable rhBMP-2 slowrelease carriers currently available. The composite will be a new type of bone substitute to be used in orthopaedics and maxillofacial surgery.展开更多
AIM: To culture human pancreatic tissue obtained from small resection specimens as a pre-clinical model for examining virus-host interactions. METHODS: Human pancreatic tissue samples (malignant and normal) were o...AIM: To culture human pancreatic tissue obtained from small resection specimens as a pre-clinical model for examining virus-host interactions. METHODS: Human pancreatic tissue samples (malignant and normal) were obtained from surgical specimens and processed immediately to tissue slices. Tissue slices were cultured ex vivo for 1-6 d in an incubator using 95% 02. Slices were subsequently analyzed for viability and morphology. In addition the slices were incubated with different viral vectors expressing the reporter genes GFP or DsRed. Expression of these reporter genes was measured at 72 h after infection.RESULTS: With the Krumdieck tissue slicer, uniform slices could be generated from pancreatic tissue but only upon embedding the tissue in 3% low melting agarose. Immunohistological examination showed the presence of all pancreatic cell types. Pancreatic normal and cancer tissue slices could be cultured for up to 6 d, while retaining viability and a moderate to good morphology. Reporter gene expression indicated that the slices could be infected and transduced efficiently by adenoviral vectors and by adeno associated viral vectors, whereas transduction with lentiviral vectors was limited. For the adenoviral vector, the transduction seemed limited to the peripheral layers of the explants. CONCLUSION: The presented system allows reproducible processing of minimal amounts of pancreatic tissue into slices uniform in size, suitable for pre-clinical evaluation of gene therapy vectors.展开更多
Intelligent hydrogels is as drug carrier, and it has a good application prospect. There are some changes factors in the human environment, such as temperature, pH. Therefore, the temperature sensitive hydrogels and pH...Intelligent hydrogels is as drug carrier, and it has a good application prospect. There are some changes factors in the human environment, such as temperature, pH. Therefore, the temperature sensitive hydrogels and pH sensitive hydrogels can release system for drugs in the body. So the paper detailed descript a novel MWCNTs good dispersion of PMAA/MWCNTs nano hybrid hydrogels. The introduction of MWCNTs significantly increased the hydrogel pH response and mechanical strength, and depends on the MWCNTs component ratio, particle size and concentration of cross-linking agent. The study found, swelling rate of hybrid hydrogels was faster than the pure PMAA hydrogel, and the swelling behavior were explained. The compression stress-strain experiments should be found, MWCNTs load transfer plays an important role in improving the mechanical properties of the hybrid hydrogels network compression.展开更多
Objective: To construct a non-replicating vaccinia virus expressing human papillomavirus 16 (HPV16) L1, L2E7 proteins as a candidate vaccine for cervical cancer. Methods: Using vaccinia virus vector, we generated ...Objective: To construct a non-replicating vaccinia virus expressing human papillomavirus 16 (HPV16) L1, L2E7 proteins as a candidate vaccine for cervical cancer. Methods: Using vaccinia virus vector, we generated a strain of non-replicating recombinant vaccinia virus vaccine expressing HPV16 L1, L2E7 proteins by homologous recombination and identified by PCR and Westernloting. Results: We demonstrated that the L1, L2E7 gene of HPV16 were integrated into vaccinia genosome and could express L1, L2E7 protein stably when infected the CEF using PCR and Western-blot assay. Conclusion: NTVJL1/L2E7 can express L1, L2E7 protein of HPV16 and can be taken as a candidate vaccine for HPV16-associated diseases.展开更多
Abstract:Objective To develop a retroviral-mediated high efficient expression system of human coagulation factor Ⅷ. Methods The LNC-FⅧBD retroviral vector was generated by cloning a human B-domain-deleted (760aa~16...Abstract:Objective To develop a retroviral-mediated high efficient expression system of human coagulation factor Ⅷ. Methods The LNC-FⅧBD retroviral vector was generated by cloning a human B-domain-deleted (760aa~1639aa) Factor Ⅷ (FⅧ) cDNA (FⅧ cDNA BD) into the retroviral vector pLNCX. Several mammalian cell lines, including NIH3T3, CHO, Cos-7 and human hepatic cell line, L-02, were transduced with viral supernatant from the highest virus-producing PA317 clone. Antigen and coagulant activity of human FⅧ in cell culture medium were measured by ELISA and a one-stage method, respectively. RT-PCR was performed for the detection of FⅧBD mRNA. Results Human FⅧ was expressed in all four target cells, with the highest FⅧ expression observed in NIH3T3. The coagulant activity of secreted FⅧ was up to 1.6U/106 cells*24?hrs-1, and the FⅧ antigen was 500?ng/106 cells*24?hrs-1. FⅧ coagulant activity and antigen expressed by transduced CHO cells were 0.12?U/106 cells*24?hrs-1 and 62.4?ng/106 cells*24?hrs-1, respectively. Human FⅧ expression was relatively low in Cos-7 and L-02 cells. RT-PCR results demonstrated transcription of FⅧcDNA BD in the target cells.Conclusions The constructed retroviral vector was able to direct high level expression of human FⅧ in various mammalian cell lines. It has potential utility in the future gene therapy for Hemophilia A.展开更多
Induced pluripotent stem (iPS) cell technology demonstrates that somatic cells can be reprogrammed to a pluripotent state by over-expressing four reprogramming factors.This technology has created an interest in derivi...Induced pluripotent stem (iPS) cell technology demonstrates that somatic cells can be reprogrammed to a pluripotent state by over-expressing four reprogramming factors.This technology has created an interest in deriving iPS cells from domesticated animals such as pigs,sheep and cattle.Moloney murine leukemia retrovirus vectors have been widely used to generate and study mouse iPS cells.However,this retrovirus system infects only mouse and rat cells,which limits its use in establishing iPS cells from other mammals.In our study,we demonstrate a novel retrovirus strategy to efficiently generate porcine iPS cells from embryonic fibroblasts.We transfected four human reprogramming factors (Oct4,Sox2,Klf4 and Myc) into fibroblasts in one step by using a VSV-G envelope-coated pantropic retrovirus that was easily packaged by GP2-293 cells.We established six embryonic stem (ES)-like cell lines in human ES cell medium supplemented with bFGF.Colonies showed a similar morphology to human ES cells with a high nuclei-cytoplasm ratio and phase-bright flat colonies.Porcine iPS cells could form embryoid bodies in vitro and differentiate into the three germ layers in vivo by forming teratomas in immunodeficient mice.展开更多
To obtain a conceptual design for a hybrid rocket motor(HRM)to be used as the Ascent Propulsion System in the Apollo lunar module,the deterministic design optimization(DDO)method is applied to the HRM design.Based on ...To obtain a conceptual design for a hybrid rocket motor(HRM)to be used as the Ascent Propulsion System in the Apollo lunar module,the deterministic design optimization(DDO)method is applied to the HRM design.Based on the results of an uncertainty analysis of HRMs,an uncertainty-based design optimization(UDO)method is also adopted to improve the design reliability.The HRM design process,which is a multidisciplinary system,is analyzed,and a mathematical model for the system design is established to compute the motor performance from the input parameters,including the input variables and model parameters.The input parameter uncertainties are quantified,and a sensitivity analysis of the model parameter uncertainties is conducted to identify the most important model parameter uncertainties for HRMs.The DDO and probabilistic UDO methods are applied to conceptual designs for an HRM to be used as a substitute for the liquid rocket motor(LRM)of the Ascent Propulsion System.The conceptual design results show that HRMs have several advantages as an alternative to the LRM of the Ascent Propulsion System,including nontoxic propellant combination,small motor volume,and comparable functions,such as restarting and throating.Comparisons of the DDO and UDO results indicate that the UDO method achieves more robust and reliable optimal designs than the DDO method.The probabilistic UDO method can be used to develop better conceptual designs for HRMs.展开更多
文摘To prepare a solid dispersion of cisapride with hydroxypropylmethyl cellulose(HPMC E5 LV) as carrier for the purpose of accelerating the in vitro drug release by means ofimproving the solubility of the model drug. Methods Alcohol and simulated gastric fluid (SGF) wereused to dissolve cisapride and HPMC in order to make the model drug dispersed homogeneously in thecarrier. The HPMC-cisapride solid dispersion was then obtained by conventional solvent evaporationmethod. Powder X-ray diffraction (XRD) was used to measure the diffraction peaks of pure carrier,pure cisapride, physical mixture of HPMC with cisapride (4:1), and HPMC-cisapride solid dispersion(4:1) to confirm the crystal existence. The solubility of pure drug and HPMC-cisapride soliddispersion was measured with water, SGF and simulated intestinal fluid (SIF) . The in vitro drugreleases of the sustained release tablet prepared with pure cisapride or HPMC-cisapride soliddispersion were investigated with water and SGF as media, respectively. Results No diffraction peakswere found by X-ray diffraction in the HPMC-cisapride solid dispersion (4:1), indicating that thedrug existed in an amorphous form at that drug-carrier ratio. Compared with the pure drug, thesolubilities of HPMC-cisapride solid dispersion are increased by 239.4% in SGF, 132.6% in water, and117.9% in SIF. According to the in vitro drug release, the sustained release tablet prepared withHPMC-cisapride solid dispersion had a faster drug release than did that prepared with pure drug. Thein vitro drug release profiles were found to comply with Higuchi's rule. Conclusion The in vitrodrug release of the sustained release tablet made by HPMC-cisapride solid dispersion is improvedowing to the increased drug solubility.
基金The author would like to thank the Nature Science Foundation of China (Grant No.60627001)the Beijing Key Laboratory for Sensor(No.KM200810772001)
文摘In order to find out the influence of the instability of angular velocity of the rotating carrier itself on the stability of silicon micromachined gyroscope, the digital models for relative error of the high and low damping gyroscope's output signal are given respectively, based on the motion equations of the silicon micromachined gyroscope. Theory proves that the output signal error of the silicon micromachined sensor is mainly caused by the instability of damping factor and the angular velocity of the rotating carrier itself. The experiment result indicates that the error of proportionality coefficient of output voltage which is caused by the instability of the angular velocity of the rotating carrier itself reaches to 4.1 %. Theoretical demonstration and experimental verification show that the instability of angular velocity of the rotating carrier itself has an important effect on the stability of low damping silicon micromachined gyroscope.
文摘By combining coral with recombinant human bone morphogenetic protein-2 (rhBMP-2), rhBMP-2/coral composite was obtained in this study. Following implantation of the composite into the muscle pouches of mice, cartilage growth was induced in the pores or on the surface of the implants at one week, woven bone at three week and lamellar bone with bone marrow at six week, and coral was absorbed partially. The induced formation of endochondral bone was time-related and rhBMP-2 dose-related. The results of this study indicate that the composite possesses a superior ability of osteogenesis, and coral acts as one of the most suitable rhBMP-2 slowrelease carriers currently available. The composite will be a new type of bone substitute to be used in orthopaedics and maxillofacial surgery.
基金Supported by The Dutch Cancer Society(grant.UvA2002-2604)
文摘AIM: To culture human pancreatic tissue obtained from small resection specimens as a pre-clinical model for examining virus-host interactions. METHODS: Human pancreatic tissue samples (malignant and normal) were obtained from surgical specimens and processed immediately to tissue slices. Tissue slices were cultured ex vivo for 1-6 d in an incubator using 95% 02. Slices were subsequently analyzed for viability and morphology. In addition the slices were incubated with different viral vectors expressing the reporter genes GFP or DsRed. Expression of these reporter genes was measured at 72 h after infection.RESULTS: With the Krumdieck tissue slicer, uniform slices could be generated from pancreatic tissue but only upon embedding the tissue in 3% low melting agarose. Immunohistological examination showed the presence of all pancreatic cell types. Pancreatic normal and cancer tissue slices could be cultured for up to 6 d, while retaining viability and a moderate to good morphology. Reporter gene expression indicated that the slices could be infected and transduced efficiently by adenoviral vectors and by adeno associated viral vectors, whereas transduction with lentiviral vectors was limited. For the adenoviral vector, the transduction seemed limited to the peripheral layers of the explants. CONCLUSION: The presented system allows reproducible processing of minimal amounts of pancreatic tissue into slices uniform in size, suitable for pre-clinical evaluation of gene therapy vectors.
文摘Intelligent hydrogels is as drug carrier, and it has a good application prospect. There are some changes factors in the human environment, such as temperature, pH. Therefore, the temperature sensitive hydrogels and pH sensitive hydrogels can release system for drugs in the body. So the paper detailed descript a novel MWCNTs good dispersion of PMAA/MWCNTs nano hybrid hydrogels. The introduction of MWCNTs significantly increased the hydrogel pH response and mechanical strength, and depends on the MWCNTs component ratio, particle size and concentration of cross-linking agent. The study found, swelling rate of hybrid hydrogels was faster than the pure PMAA hydrogel, and the swelling behavior were explained. The compression stress-strain experiments should be found, MWCNTs load transfer plays an important role in improving the mechanical properties of the hybrid hydrogels network compression.
基金Support by a grant from the National High Technology Research and Development Program, China (No.2002AA216041).
文摘Objective: To construct a non-replicating vaccinia virus expressing human papillomavirus 16 (HPV16) L1, L2E7 proteins as a candidate vaccine for cervical cancer. Methods: Using vaccinia virus vector, we generated a strain of non-replicating recombinant vaccinia virus vaccine expressing HPV16 L1, L2E7 proteins by homologous recombination and identified by PCR and Westernloting. Results: We demonstrated that the L1, L2E7 gene of HPV16 were integrated into vaccinia genosome and could express L1, L2E7 protein stably when infected the CEF using PCR and Western-blot assay. Conclusion: NTVJL1/L2E7 can express L1, L2E7 protein of HPV16 and can be taken as a candidate vaccine for HPV16-associated diseases.
基金ThisworkwassupportedbytheDrug developmentFoundationof ShanghaiScienceandTechnicalCommittee (No .975 4190 0 1)andDr .ClydeWuFoundationofShanghaiInstituteofHematology .
文摘Abstract:Objective To develop a retroviral-mediated high efficient expression system of human coagulation factor Ⅷ. Methods The LNC-FⅧBD retroviral vector was generated by cloning a human B-domain-deleted (760aa~1639aa) Factor Ⅷ (FⅧ) cDNA (FⅧ cDNA BD) into the retroviral vector pLNCX. Several mammalian cell lines, including NIH3T3, CHO, Cos-7 and human hepatic cell line, L-02, were transduced with viral supernatant from the highest virus-producing PA317 clone. Antigen and coagulant activity of human FⅧ in cell culture medium were measured by ELISA and a one-stage method, respectively. RT-PCR was performed for the detection of FⅧBD mRNA. Results Human FⅧ was expressed in all four target cells, with the highest FⅧ expression observed in NIH3T3. The coagulant activity of secreted FⅧ was up to 1.6U/106 cells*24?hrs-1, and the FⅧ antigen was 500?ng/106 cells*24?hrs-1. FⅧ coagulant activity and antigen expressed by transduced CHO cells were 0.12?U/106 cells*24?hrs-1 and 62.4?ng/106 cells*24?hrs-1, respectively. Human FⅧ expression was relatively low in Cos-7 and L-02 cells. RT-PCR results demonstrated transcription of FⅧcDNA BD in the target cells.Conclusions The constructed retroviral vector was able to direct high level expression of human FⅧ in various mammalian cell lines. It has potential utility in the future gene therapy for Hemophilia A.
基金supported by the National Basic Research Program of China (Grant Nos. 2009CB941003, 2011CBA0110 and 2011CBA01000)
文摘Induced pluripotent stem (iPS) cell technology demonstrates that somatic cells can be reprogrammed to a pluripotent state by over-expressing four reprogramming factors.This technology has created an interest in deriving iPS cells from domesticated animals such as pigs,sheep and cattle.Moloney murine leukemia retrovirus vectors have been widely used to generate and study mouse iPS cells.However,this retrovirus system infects only mouse and rat cells,which limits its use in establishing iPS cells from other mammals.In our study,we demonstrate a novel retrovirus strategy to efficiently generate porcine iPS cells from embryonic fibroblasts.We transfected four human reprogramming factors (Oct4,Sox2,Klf4 and Myc) into fibroblasts in one step by using a VSV-G envelope-coated pantropic retrovirus that was easily packaged by GP2-293 cells.We established six embryonic stem (ES)-like cell lines in human ES cell medium supplemented with bFGF.Colonies showed a similar morphology to human ES cells with a high nuclei-cytoplasm ratio and phase-bright flat colonies.Porcine iPS cells could form embryoid bodies in vitro and differentiate into the three germ layers in vivo by forming teratomas in immunodeficient mice.
基金supported by the National Natural Science Foundation of China(Grant No.51305014)the China Postdoctoral Science Foundation(Grant No.2013M540842)
文摘To obtain a conceptual design for a hybrid rocket motor(HRM)to be used as the Ascent Propulsion System in the Apollo lunar module,the deterministic design optimization(DDO)method is applied to the HRM design.Based on the results of an uncertainty analysis of HRMs,an uncertainty-based design optimization(UDO)method is also adopted to improve the design reliability.The HRM design process,which is a multidisciplinary system,is analyzed,and a mathematical model for the system design is established to compute the motor performance from the input parameters,including the input variables and model parameters.The input parameter uncertainties are quantified,and a sensitivity analysis of the model parameter uncertainties is conducted to identify the most important model parameter uncertainties for HRMs.The DDO and probabilistic UDO methods are applied to conceptual designs for an HRM to be used as a substitute for the liquid rocket motor(LRM)of the Ascent Propulsion System.The conceptual design results show that HRMs have several advantages as an alternative to the LRM of the Ascent Propulsion System,including nontoxic propellant combination,small motor volume,and comparable functions,such as restarting and throating.Comparisons of the DDO and UDO results indicate that the UDO method achieves more robust and reliable optimal designs than the DDO method.The probabilistic UDO method can be used to develop better conceptual designs for HRMs.