AIM: To investigate the anticancer effect of a traditional Chinese medicine gambogic acid (GA) in human gastric cancer line BGC-823 and further study the mechanism of apoptosis induction of GA.METHODS: Low differentia...AIM: To investigate the anticancer effect of a traditional Chinese medicine gambogic acid (GA) in human gastric cancer line BGC-823 and further study the mechanism of apoptosis induction of GA.METHODS: Low differential human gastric cancer line BGC-823 were treated with GA at different doses and different times, the inhibitory rates were detected by MTT assay. Apoptosis induced by GA in BGC-823 cells was observed by Annexin-V/PI doubling staining flow cytometry assay. And T/C (%) was chosen to detect the inhibition of GA on human gastric adenocarcinoma BGC-823 nude mice xenografts. Apoptosis on nude mice xenografts was observed by Annexin-V/PI doubling staining flow cytometry assay and DNA fragmentation assay. To further determine the molecular mechanism of apoptosis induced by GA, the changes on the expression of bcl-2 and bax genes were detected by RT-PCR.RESULTS: After incubation with GA, low differential human gastric cancer line BGC-823 was dramatically inhibited in a dose-dependent manner. After these cells were exposedto GA for 24, 48 and 72 h, the IC50 value was 1.02±0.05, 1.41±0.20 and 1.14±0.19 μmol/L, respectively. Apoptosis in BGC-823 cells induced by GA was observed by AnnexinV/PI doubling staining flow cytometry assay. The apoptotic population of BGC-823 cells was about 12.96% and 24.58%, respectively, when cells were incubated with 1.2 μmol/L GA for 48 and 72 h. T/C (%) of human gastric carcinoma adenocarcinoma BGC-823 nude mice xenografts was 44.3, when the nude mice were treated with GA (8 mg/kg). Meanwhile, apoptosis induced by GA was observed in human gastric carcinoma adenocarcinoma BGC-823 nude mice xenografts. The increase of bax gene and the decrease of bc1-2 gene expressions were found by RT-PCR.CONCLUSION: The inhibition of GA on human gastric cancer line BGC-823 was confirmed. This effect connects with the inducing apoptosis in BGC-823 cells and the molecular mechanism might be related to the reduction of expression of apoptosis-regulated gene bcl-2, and the improvement of the expression of apoptosis-regulated gene bax. The result was also confirmed in vivo.展开更多
AIM: To elucidate the mechanism by which somatostatin and its analogue exert the influence on liver fibrosis, and to investigate the mRNA expression of somatostatin receptors subtypes (SSTRs) and the distribution of s...AIM: To elucidate the mechanism by which somatostatin and its analogue exert the influence on liver fibrosis, and to investigate the mRNA expression of somatostatin receptors subtypes (SSTRs) and the distribution of somatostatin analogue octreotide in rat hepatic stellate cells (HSCs). METHODS: HSCs were isolated from Sprague Dawley (SD) rats by in situ perfusion and density gradient centrifugation. After several passages, the mRNA expression of 5 subtypes of SSTRs were assessed by reverse transcription-polymerase chain reaction (RT-PCR). HSCs were planted on coverslip and co-cultured with octreotide tagged by FITC. Then the distribution of FITC fluorescence was observed under laser scanning confocal microscope (LSCM) in 12-24 h. RESULTS: There were mRNA expression of SSTR2, SSTR3 and SSTR5 but not SSTR1 and SSTR4 in SD rat HSCs. The mRNA expression level of SSTR2 was significantly higher than that of other subtypes (P<0.01). FITC fluorescence of octreotide was clearly observed on the surface and in the cytoplasm, but not in the nuclei of HSCs under LSCM. CONCLUSION: The effect exerted by somatostatin and its analogues on HSCs may mainly depend on the expression of SSTR2, SSTR3 and SSTR5. Octreotide can perfectlycombine with HSCs, and thereby exerts its biological activity on regulating the characters of active HSCs. This provides a potential prevention and management against liver fibrosis.展开更多
AIM: To investigate the expression of cancer-testis (CT) anigens MAGE-1, SSX-1 ,CTp11 and HCA587 genes in hepatocellular carcinoma (HCC) and the possibility of applying these antigens as targets for specific immunoth...AIM: To investigate the expression of cancer-testis (CT) anigens MAGE-1, SSX-1 ,CTp11 and HCA587 genes in hepatocellular carcinoma (HCC) and the possibility of applying these antigens as targets for specific immunotherapy for HCC. METHODS: Expression levels of MAGE-1, SSX-1, CTp11 and HCA587mRNA were detected with reverse transcription polymerase chain reaction (RT-PCR) in HCC tissues and corresponding adjacent non-cancerous tissues from 105 HCC patients, 40 samples of cirrhosis and normal liver tissues.Genes of five samples with positive PCR results were sequenced.RESULTS: Of 105 HCC tissues, MAGE1, SSX-1 ,CTp11 and HCA587mRNA expressions were detectable in 75.2%(79/105),72.4%(76/105), 62.9%(66/105) and 56.2%(59/105) of HCC samples, respectively. About 93.3%(98/105), 72.4%(76/105),48.6%(51/105) and 37.1%(39/105) of HCC tissues positively expressed at least one, two, three, and four members of CT antigens, respectively. Conversely, only SSX-1 could be detectable in 2.9%(3/105) of the corresponding adjacent non-HCC tissues in which no metastatic lesion was found.Of the latter 3 patients, biopsy samples far from tumor were obtained in 2 patients and RT-PCR indicated no expression of SSX-1 mRNA in these two samples. In addition,none of 40 samples of cirrhotic and normal liver tissues expressed CT antigen gene mRNA. DNA sequences confirmed that the RT-PCR products were true target cDNA. No relationship was found between expression of CT antigens and clinico pathological indicators such as age,gender, tumor size, degree of tumor differentiation, serum α-fetoprotein level and infection of hepatitis B virus or hepatitis C virus (P＞0.05).CONCLUSION: CT antigens genes (MAGE-1, SSX-1, CTp11 and HCA587) are expressed with high percentage and specificity in HCC and their products are promising targets for antigen-specific immunotherapy of HCC. High frequent co-expression of multiple members of CT antigens in HCC provides possibility of polyvalent vaccinations for HCC.展开更多
Carried-Heat Partial Gasification Combined cycle is a novel combined cycle which was proposed by Thermal Engineering Department of Tsinghua University in 1992. The idea of the system comes from the situation that the ...Carried-Heat Partial Gasification Combined cycle is a novel combined cycle which was proposed by Thermal Engineering Department of Tsinghua University in 1992. The idea of the system comes from the situation that the efficiency of the power plants in China is much lower than that of the advanced countries, but the coal consumption is much higher, which brings about the waste of primary energy resources and the pollution of the environment. With the deep study of the gasification technology, Coke Carried-Heat Gasification Coal-Fired Combined Cycle, as the improved system, came into birth in 1996 based on the partial gasification one. At the end of 1997, a new cycle scheme similar to IGCC was created. This paper focuses on several classes combined cycle put forward by Tsinghua University, depending on the plant configuration and carbon conversion, making the solution a viable and attractive option for efficient coal utilization.展开更多
The scheme of differential-velocity circulating fluidized bed was put forward by Thermal EngineeringDepartment of Tsinghua university in 1992 and got patent simultaneously. An internal bed material circulation in comb...The scheme of differential-velocity circulating fluidized bed was put forward by Thermal EngineeringDepartment of Tsinghua university in 1992 and got patent simultaneously. An internal bed material circulation in combustor can be established by the discrepancy of entrainment at different air velocity, andseparates the combustor into three different velocity regions, which constitutes the differential-velocityinside circulation. Mathematical modeling and simulation may facilitate understanding, developmentand operation of this new process. Here cell model method was adopted to set up the model.展开更多
基金Supported by The National High Technology Research and Development Program Foundation of China, 863 Program, No. 2002AA2Z3112the Ministry of Education Science and Technology Program, No. 104099affiliated to National Natural Science Foundation of China, No. 30472044
文摘AIM: To investigate the anticancer effect of a traditional Chinese medicine gambogic acid (GA) in human gastric cancer line BGC-823 and further study the mechanism of apoptosis induction of GA.METHODS: Low differential human gastric cancer line BGC-823 were treated with GA at different doses and different times, the inhibitory rates were detected by MTT assay. Apoptosis induced by GA in BGC-823 cells was observed by Annexin-V/PI doubling staining flow cytometry assay. And T/C (%) was chosen to detect the inhibition of GA on human gastric adenocarcinoma BGC-823 nude mice xenografts. Apoptosis on nude mice xenografts was observed by Annexin-V/PI doubling staining flow cytometry assay and DNA fragmentation assay. To further determine the molecular mechanism of apoptosis induced by GA, the changes on the expression of bcl-2 and bax genes were detected by RT-PCR.RESULTS: After incubation with GA, low differential human gastric cancer line BGC-823 was dramatically inhibited in a dose-dependent manner. After these cells were exposedto GA for 24, 48 and 72 h, the IC50 value was 1.02±0.05, 1.41±0.20 and 1.14±0.19 μmol/L, respectively. Apoptosis in BGC-823 cells induced by GA was observed by AnnexinV/PI doubling staining flow cytometry assay. The apoptotic population of BGC-823 cells was about 12.96% and 24.58%, respectively, when cells were incubated with 1.2 μmol/L GA for 48 and 72 h. T/C (%) of human gastric carcinoma adenocarcinoma BGC-823 nude mice xenografts was 44.3, when the nude mice were treated with GA (8 mg/kg). Meanwhile, apoptosis induced by GA was observed in human gastric carcinoma adenocarcinoma BGC-823 nude mice xenografts. The increase of bax gene and the decrease of bc1-2 gene expressions were found by RT-PCR.CONCLUSION: The inhibition of GA on human gastric cancer line BGC-823 was confirmed. This effect connects with the inducing apoptosis in BGC-823 cells and the molecular mechanism might be related to the reduction of expression of apoptosis-regulated gene bcl-2, and the improvement of the expression of apoptosis-regulated gene bax. The result was also confirmed in vivo.
基金Supported by National Nature Science Foundation of China,No.30271270
文摘AIM: To elucidate the mechanism by which somatostatin and its analogue exert the influence on liver fibrosis, and to investigate the mRNA expression of somatostatin receptors subtypes (SSTRs) and the distribution of somatostatin analogue octreotide in rat hepatic stellate cells (HSCs). METHODS: HSCs were isolated from Sprague Dawley (SD) rats by in situ perfusion and density gradient centrifugation. After several passages, the mRNA expression of 5 subtypes of SSTRs were assessed by reverse transcription-polymerase chain reaction (RT-PCR). HSCs were planted on coverslip and co-cultured with octreotide tagged by FITC. Then the distribution of FITC fluorescence was observed under laser scanning confocal microscope (LSCM) in 12-24 h. RESULTS: There were mRNA expression of SSTR2, SSTR3 and SSTR5 but not SSTR1 and SSTR4 in SD rat HSCs. The mRNA expression level of SSTR2 was significantly higher than that of other subtypes (P<0.01). FITC fluorescence of octreotide was clearly observed on the surface and in the cytoplasm, but not in the nuclei of HSCs under LSCM. CONCLUSION: The effect exerted by somatostatin and its analogues on HSCs may mainly depend on the expression of SSTR2, SSTR3 and SSTR5. Octreotide can perfectlycombine with HSCs, and thereby exerts its biological activity on regulating the characters of active HSCs. This provides a potential prevention and management against liver fibrosis.
文摘AIM: To investigate the expression of cancer-testis (CT) anigens MAGE-1, SSX-1 ,CTp11 and HCA587 genes in hepatocellular carcinoma (HCC) and the possibility of applying these antigens as targets for specific immunotherapy for HCC. METHODS: Expression levels of MAGE-1, SSX-1, CTp11 and HCA587mRNA were detected with reverse transcription polymerase chain reaction (RT-PCR) in HCC tissues and corresponding adjacent non-cancerous tissues from 105 HCC patients, 40 samples of cirrhosis and normal liver tissues.Genes of five samples with positive PCR results were sequenced.RESULTS: Of 105 HCC tissues, MAGE1, SSX-1 ,CTp11 and HCA587mRNA expressions were detectable in 75.2%(79/105),72.4%(76/105), 62.9%(66/105) and 56.2%(59/105) of HCC samples, respectively. About 93.3%(98/105), 72.4%(76/105),48.6%(51/105) and 37.1%(39/105) of HCC tissues positively expressed at least one, two, three, and four members of CT antigens, respectively. Conversely, only SSX-1 could be detectable in 2.9%(3/105) of the corresponding adjacent non-HCC tissues in which no metastatic lesion was found.Of the latter 3 patients, biopsy samples far from tumor were obtained in 2 patients and RT-PCR indicated no expression of SSX-1 mRNA in these two samples. In addition,none of 40 samples of cirrhotic and normal liver tissues expressed CT antigen gene mRNA. DNA sequences confirmed that the RT-PCR products were true target cDNA. No relationship was found between expression of CT antigens and clinico pathological indicators such as age,gender, tumor size, degree of tumor differentiation, serum α-fetoprotein level and infection of hepatitis B virus or hepatitis C virus (P＞0.05).CONCLUSION: CT antigens genes (MAGE-1, SSX-1, CTp11 and HCA587) are expressed with high percentage and specificity in HCC and their products are promising targets for antigen-specific immunotherapy of HCC. High frequent co-expression of multiple members of CT antigens in HCC provides possibility of polyvalent vaccinations for HCC.
文摘Carried-Heat Partial Gasification Combined cycle is a novel combined cycle which was proposed by Thermal Engineering Department of Tsinghua University in 1992. The idea of the system comes from the situation that the efficiency of the power plants in China is much lower than that of the advanced countries, but the coal consumption is much higher, which brings about the waste of primary energy resources and the pollution of the environment. With the deep study of the gasification technology, Coke Carried-Heat Gasification Coal-Fired Combined Cycle, as the improved system, came into birth in 1996 based on the partial gasification one. At the end of 1997, a new cycle scheme similar to IGCC was created. This paper focuses on several classes combined cycle put forward by Tsinghua University, depending on the plant configuration and carbon conversion, making the solution a viable and attractive option for efficient coal utilization.
文摘The scheme of differential-velocity circulating fluidized bed was put forward by Thermal EngineeringDepartment of Tsinghua university in 1992 and got patent simultaneously. An internal bed material circulation in combustor can be established by the discrepancy of entrainment at different air velocity, andseparates the combustor into three different velocity regions, which constitutes the differential-velocityinside circulation. Mathematical modeling and simulation may facilitate understanding, developmentand operation of this new process. Here cell model method was adopted to set up the model.
