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
Objective:To express the soluble recombinant hemangiopoietin protein in E.coli BL21(DE3).Methods:Using human fetal live cDNA as a template,a partial cDNA fragment of HAPO coding N-terminal region was subcloned into pl...Objective:To express the soluble recombinant hemangiopoietin protein in E.coli BL21(DE3).Methods:Using human fetal live cDNA as a template,a partial cDNA fragment of HAPO coding N-terminal region was subcloned into plasmids pTrc99,pQE60 and pET32c to construct different recombinant prokaryotic expression systems.After selecting,the soluble rhHAPO fusion protein was expressed stably in E.coli BL21(DE3) by vector pET32c-HAPO and further isolated by nickelnitrilotriacetic acid(NTA) affinity chromatography.After cleavage with enterokinase,the rhHAPO protein was applied to Fast Flow SP sepharose column.Results:The rhHAPO protein had a purity of more than 95% and a good bioactivity based on the cell adhesion assay in ECV304 cells.Conclusion:We have established a protein engineering system to produce rhHAPO which may provide the possibility for clinical application.展开更多
Endotoxins(also known as lipopolysaccharides(LPS)) are undesirable by-products of recombinant proteins,purified from Escherichia coli.LPS can be considered stable under a wide range of temperature and pH,making their ...Endotoxins(also known as lipopolysaccharides(LPS)) are undesirable by-products of recombinant proteins,purified from Escherichia coli.LPS can be considered stable under a wide range of temperature and pH,making their removal one of the most difficult tasks in downstream processes during protein purification.The inherent toxicity of LPS makes their removal an important step for the application of these proteins in several biological assays and for a safe parenteral administration.Immobilized metal affinity chromatography(IMAC) enables the affinity interactions between the metal ions(immobilized on the support through the chelating compound) and the target molecules,thus enabling high-efficiency separation of the target molecules from other components present in a mixture.Affinity chromatography is applied with Ca2+-iminodiacetic acid(IDA) to remove most of the LPS contaminants from the end product(more than90%).In this study,the adsorption of LPS on an IDA-Ca2+ was investigated.The adsorption Freundlich isotherm of LPS-IDA-Ca2+ provides a theoretical basis for LPS removal.It was found that LPS is bound mainly by interactions between the phosphate group in LPS and Ca2+ ligands on the beads.The factors such as pH(4.0 or 5.5) and ionic strength(1.0 mol/L) are essential to obtain effective removal of LPS for contaminant levels between endotoxin' concentration values less than100 EU/mL and 100 000 EU/mL.This new protocol represents a substantial advantage in time,effort,and production costs.展开更多
In this article, we introduce the system of high throughput screening (HTS). Its role in new drug study and current development is described. The relationship between research achievements of genome study and new type...In this article, we introduce the system of high throughput screening (HTS). Its role in new drug study and current development is described. The relationship between research achievements of genome study and new type screening model of new drugs is emphasized. The personal opinions of current problems about HTS study in China are raised.展开更多
Acute myocardial infarction （AMI） is an acute cardiovascular emergency. This study was undertaken to assess the effect of tumor necrosis factor-a （TNF-a） on ventricular arrhythmias induced byAMI in rats in vivo. ...Acute myocardial infarction （AMI） is an acute cardiovascular emergency. This study was undertaken to assess the effect of tumor necrosis factor-a （TNF-a） on ventricular arrhythmias induced byAMI in rats in vivo. Two hundred and forty male Wistar rats were randomized into a sham- operation group, an AMI group, and a recombinant human tumor necrosis factor receptor：Fc fusion protein（rhTNFR：Fc） group. Acute anterior wall myocardial infarction was produced in the AMI group by ligating the left anterior descending coronary artery （LAD）, and there was no ligation but operation in the sham-operation group. The rhTNFR：Fc group was treated with rhTNFR：Fc（10 mg/kg）, a TNF-a antagonist, 24 hours before LAD ligation. The spontaneous and induced programmed electrical stimulation ventricular arrhythmias were recorded at baseline and 10 minutes, 20 minutes, 30 minutes, 60 minutes, 3 hours, 6 hours and 12 hours after ligation. At the same time the protein and mRNA expression levels of TNF-a among different groups were detected by histochemistry and real-time fluorescent quantitative PCR. Expression of TNF-a increased markedly from 10 minutes after infarction, peaked at 20-30 minutes, and returned to baseline gradually in the AMI group and rhTNFR：Fc group. The time- windows of spontaneous and induced ventricular arrhythmias were similar. Compared with the AMI group, the rhTNFR：Fc group showed a lesser expression of TNF-a protein and a lower incidence of ventricular arrhythmias （P〈0.05）. There was no obvious change in the sham-operation group. The expression of TNF-a induced by AMI could contribute to the onset of ventricular arrhythmias.展开更多
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the Natural Science Foundation of China (30300186)the Grant of 863 projects from the Ministry of Science & Technology of China (2002AA223354)
文摘Objective:To express the soluble recombinant hemangiopoietin protein in E.coli BL21(DE3).Methods:Using human fetal live cDNA as a template,a partial cDNA fragment of HAPO coding N-terminal region was subcloned into plasmids pTrc99,pQE60 and pET32c to construct different recombinant prokaryotic expression systems.After selecting,the soluble rhHAPO fusion protein was expressed stably in E.coli BL21(DE3) by vector pET32c-HAPO and further isolated by nickelnitrilotriacetic acid(NTA) affinity chromatography.After cleavage with enterokinase,the rhHAPO protein was applied to Fast Flow SP sepharose column.Results:The rhHAPO protein had a purity of more than 95% and a good bioactivity based on the cell adhesion assay in ECV304 cells.Conclusion:We have established a protein engineering system to produce rhHAPO which may provide the possibility for clinical application.
基金supported by grants from the Brazilian Agency Coordination of Graduate Level Training(CAPES,project 0366/09-9)State of So Paulo Research Support Foundation(FAPESP-Brazil,project 2005/60159-7)
文摘Endotoxins(also known as lipopolysaccharides(LPS)) are undesirable by-products of recombinant proteins,purified from Escherichia coli.LPS can be considered stable under a wide range of temperature and pH,making their removal one of the most difficult tasks in downstream processes during protein purification.The inherent toxicity of LPS makes their removal an important step for the application of these proteins in several biological assays and for a safe parenteral administration.Immobilized metal affinity chromatography(IMAC) enables the affinity interactions between the metal ions(immobilized on the support through the chelating compound) and the target molecules,thus enabling high-efficiency separation of the target molecules from other components present in a mixture.Affinity chromatography is applied with Ca2+-iminodiacetic acid(IDA) to remove most of the LPS contaminants from the end product(more than90%).In this study,the adsorption of LPS on an IDA-Ca2+ was investigated.The adsorption Freundlich isotherm of LPS-IDA-Ca2+ provides a theoretical basis for LPS removal.It was found that LPS is bound mainly by interactions between the phosphate group in LPS and Ca2+ ligands on the beads.The factors such as pH(4.0 or 5.5) and ionic strength(1.0 mol/L) are essential to obtain effective removal of LPS for contaminant levels between endotoxin' concentration values less than100 EU/mL and 100 000 EU/mL.This new protocol represents a substantial advantage in time,effort,and production costs.
文摘In this article, we introduce the system of high throughput screening (HTS). Its role in new drug study and current development is described. The relationship between research achievements of genome study and new type screening model of new drugs is emphasized. The personal opinions of current problems about HTS study in China are raised.
文摘Acute myocardial infarction （AMI） is an acute cardiovascular emergency. This study was undertaken to assess the effect of tumor necrosis factor-a （TNF-a） on ventricular arrhythmias induced byAMI in rats in vivo. Two hundred and forty male Wistar rats were randomized into a sham- operation group, an AMI group, and a recombinant human tumor necrosis factor receptor：Fc fusion protein（rhTNFR：Fc） group. Acute anterior wall myocardial infarction was produced in the AMI group by ligating the left anterior descending coronary artery （LAD）, and there was no ligation but operation in the sham-operation group. The rhTNFR：Fc group was treated with rhTNFR：Fc（10 mg/kg）, a TNF-a antagonist, 24 hours before LAD ligation. The spontaneous and induced programmed electrical stimulation ventricular arrhythmias were recorded at baseline and 10 minutes, 20 minutes, 30 minutes, 60 minutes, 3 hours, 6 hours and 12 hours after ligation. At the same time the protein and mRNA expression levels of TNF-a among different groups were detected by histochemistry and real-time fluorescent quantitative PCR. Expression of TNF-a increased markedly from 10 minutes after infarction, peaked at 20-30 minutes, and returned to baseline gradually in the AMI group and rhTNFR：Fc group. The time- windows of spontaneous and induced ventricular arrhythmias were similar. Compared with the AMI group, the rhTNFR：Fc group showed a lesser expression of TNF-a protein and a lower incidence of ventricular arrhythmias （P〈0.05）. There was no obvious change in the sham-operation group. The expression of TNF-a induced by AMI could contribute to the onset of ventricular arrhythmias.
