In the recent decades, the incidence of hepatocellular carcinoma (HCC) has been found to be increasing in males in some countries. In China, HCC ranked second of cancer mortality since 1990s. Hepatitis B and C viruses...In the recent decades, the incidence of hepatocellular carcinoma (HCC) has been found to be increasing in males in some countries. In China, HCC ranked second of cancer mortality since 1990s. Hepatitis B and C viruses (HBV and HCV) and dietary aflatoxin intake remain the major causative factors of HCC. Surgery plays a major role in the treatment of HCC, particularly for small HCC. Downstaging unresectable huge HCC to smaller HCC and followed by resection will probably be a new approach for further study. Liver transplantation is indicated for small HCC, however, some issues remain to be solved.Different modes of 'regional cancer therapy for HCC' have been tried. Systemic chemotherapy has been disappointing in the past but the future can be promising.Biotherapy, such as cytokines, differentiation inducers,anti-angiogenic agents, gene therapy and tumor vaccine will probably play a role, particularly in the prevention of tumor recurrence. HCC invasiveness is currently the major target of study. Tremendous works have been done at the molecular level, which will provide clues for biomarker of HCC progressionas well as targets for intervention.展开更多
改革开放政策实施以来,流动人口成为我国经济高速增长和城镇化进程的一个重要推动力量,同时,值得关注的是各地区之间呈现出来的差异化发展水平和创业活跃程度。流动人口聚集是如何影响中国城市创业活跃度的?为了回答这一问题,本文将异...改革开放政策实施以来,流动人口成为我国经济高速增长和城镇化进程的一个重要推动力量,同时,值得关注的是各地区之间呈现出来的差异化发展水平和创业活跃程度。流动人口聚集是如何影响中国城市创业活跃度的?为了回答这一问题,本文将异质性社会个体与企业家创业的职业选择假设引入到垂直联系的自由企业家模型(footloose entrepreneur model with vertical linkage,FEVL)中,通过理论模型揭示了流动人口对城市创业活跃度的作用机理。在此基础上,利用2010—2014年全国56个城市的面板数据对这一问题进行了实证分析。研究发现,较大的市场规模、较强的知识溢出效应与较低的中间投入品价格是城市吸引流动人口特别是创业型个体的重要动因,并进而提升了城市的创业活跃度。而基于固定效应模型和D&K方法的实证分析结果也表明,流动人口比例会提高城市创业活跃度,城市流动人口规模越大,创业活跃度越高。本研究从流动人口的视角揭示了中国地区之间创业活跃度的差异之谜,同时也拓展了创业研究的经济地理和制度的分析。展开更多
AIM: To establish clone cells with different metastatic potential for the study of metastasis-related mechanisms. METHODS: Cloning procedure was performed on parental hepatocellular carcinoma (HCC) cell line MHCC97, a...AIM: To establish clone cells with different metastatic potential for the study of metastasis-related mechanisms. METHODS: Cloning procedure was performed on parental hepatocellular carcinoma (HCC) cell line MHCC97, and biological characteristics of the target clones selected by in vivo screening were studied. RESULTS: Two clones with high (MHCC97-H) and low (MHCC97-L) metastatic potential were isolated from the parent cell line. Compared with MHCC97-L, MHCC97-H had smaller cell size (average cell diameter 43 microm vs 50 microm) and faster in vitro and in vivo growth rate (tumor cell doubling time was 34.2h vs 60.0h). The main ranges of chromosomes were 55-58 in MHCC97-H and 57-62 in MHCC97-L. Boyden chamber in vitro invasion assay demonstrated that the number of penetrating cells through the artificial basement membrane was (37.5 +/- 11.0) cells/field for MHCC97-H vs (17.7 +/- 6.3)/field for MHCC97-L. The proportions of cells in G0-G1 phase, S phase, and G2-M phase for MHCC97-H/MHCC97-L were 0.56/0.65, 0.28/0.25 and 0.16/0.10, respectively, as measured by flow cytometry. The serum AFP levels in nude mice 5wk after orthotopic implantation of tumor tissue were (246 +/- 66) microg.L(-1) for MHCC97-H and (91 +/- 66) microg.L(-1) for MHCC97-L. The pulmonary metastatic rate was 100% (10/10) vs 40% (4/10). CONCLUSION: Two clones of the same genetic background but with different biological behaviors were established, which could be valuable models for investigation on HCC metastasis.展开更多
文摘In the recent decades, the incidence of hepatocellular carcinoma (HCC) has been found to be increasing in males in some countries. In China, HCC ranked second of cancer mortality since 1990s. Hepatitis B and C viruses (HBV and HCV) and dietary aflatoxin intake remain the major causative factors of HCC. Surgery plays a major role in the treatment of HCC, particularly for small HCC. Downstaging unresectable huge HCC to smaller HCC and followed by resection will probably be a new approach for further study. Liver transplantation is indicated for small HCC, however, some issues remain to be solved.Different modes of 'regional cancer therapy for HCC' have been tried. Systemic chemotherapy has been disappointing in the past but the future can be promising.Biotherapy, such as cytokines, differentiation inducers,anti-angiogenic agents, gene therapy and tumor vaccine will probably play a role, particularly in the prevention of tumor recurrence. HCC invasiveness is currently the major target of study. Tremendous works have been done at the molecular level, which will provide clues for biomarker of HCC progressionas well as targets for intervention.
文摘改革开放政策实施以来,流动人口成为我国经济高速增长和城镇化进程的一个重要推动力量,同时,值得关注的是各地区之间呈现出来的差异化发展水平和创业活跃程度。流动人口聚集是如何影响中国城市创业活跃度的?为了回答这一问题,本文将异质性社会个体与企业家创业的职业选择假设引入到垂直联系的自由企业家模型(footloose entrepreneur model with vertical linkage,FEVL)中,通过理论模型揭示了流动人口对城市创业活跃度的作用机理。在此基础上,利用2010—2014年全国56个城市的面板数据对这一问题进行了实证分析。研究发现,较大的市场规模、较强的知识溢出效应与较低的中间投入品价格是城市吸引流动人口特别是创业型个体的重要动因,并进而提升了城市的创业活跃度。而基于固定效应模型和D&K方法的实证分析结果也表明,流动人口比例会提高城市创业活跃度,城市流动人口规模越大,创业活跃度越高。本研究从流动人口的视角揭示了中国地区之间创业活跃度的差异之谜,同时也拓展了创业研究的经济地理和制度的分析。
基金Supportod ty the State Key Basic Research Program Grant G1998051211 the Fund for Leading Specialty of Shanghai Metropolitan Bureau of Public Health.
文摘AIM: To establish clone cells with different metastatic potential for the study of metastasis-related mechanisms. METHODS: Cloning procedure was performed on parental hepatocellular carcinoma (HCC) cell line MHCC97, and biological characteristics of the target clones selected by in vivo screening were studied. RESULTS: Two clones with high (MHCC97-H) and low (MHCC97-L) metastatic potential were isolated from the parent cell line. Compared with MHCC97-L, MHCC97-H had smaller cell size (average cell diameter 43 microm vs 50 microm) and faster in vitro and in vivo growth rate (tumor cell doubling time was 34.2h vs 60.0h). The main ranges of chromosomes were 55-58 in MHCC97-H and 57-62 in MHCC97-L. Boyden chamber in vitro invasion assay demonstrated that the number of penetrating cells through the artificial basement membrane was (37.5 +/- 11.0) cells/field for MHCC97-H vs (17.7 +/- 6.3)/field for MHCC97-L. The proportions of cells in G0-G1 phase, S phase, and G2-M phase for MHCC97-H/MHCC97-L were 0.56/0.65, 0.28/0.25 and 0.16/0.10, respectively, as measured by flow cytometry. The serum AFP levels in nude mice 5wk after orthotopic implantation of tumor tissue were (246 +/- 66) microg.L(-1) for MHCC97-H and (91 +/- 66) microg.L(-1) for MHCC97-L. The pulmonary metastatic rate was 100% (10/10) vs 40% (4/10). CONCLUSION: Two clones of the same genetic background but with different biological behaviors were established, which could be valuable models for investigation on HCC metastasis.
