AIM: To develop an in vitro three-dimensional (3-D) angiogenesis system to analyse the capillary sprouts induced in response to the concentration ranges of basic fibroblast growth factor (bFGF) and vascular endothelia...AIM: To develop an in vitro three-dimensional (3-D) angiogenesis system to analyse the capillary sprouts induced in response to the concentration ranges of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) and to quantify their synergistic activity.METHODS: Microcarriers (MCs) coated with human microvascular endothelial cells (HMVECs) were embedded in fibrin gel and cultured in 24-well plates with assay media. The growth factors bFGF, or VEGF, or both were added to the system. The wells (n = 8/group) were digitally photographed and the average length of capillary-like sprouts (ALS) from each microcarrier was quantitated.RESULTS: In aprotinin-stabilized fibrin matrix, human microvascular endothelial cells on the MCs invaded fibrin,forming sprouts and capillary networks with lumina. The angiogenic effects of bFGF or VEGF were dose-clependent in bhe range from 10 to 40 ng/mL. At d 1, 10 ng/mL of bFGF and VEGF induced angiogenesis with an ALS of 32.13±16.6 μm and 43.75±27.92 μm, respectively, which were significantly higher than that of the control (5.88±4.45 μm, P<0.01),and the differences became more significant as the time increased. In addition, the combination of 10 ng/mL of bFGF and VEGF each induced a more significant effect than the summed effects of bFGF (10 ng/mL) alone and VEGF (10 ng/mL) alone when analyzed using SPSS system for general linear model (GLM) (P= 0.011), and bhat also exceeded the effects by 20 ng/mL of either bFGF or VEGF.CONCLUSION: A microcarrier-based in vitro threedimensional angiogenesis model can be developed in fibrin.It offers a unique system for quantitative analysis of angiogenesis. Both bFGF and VEGF exert their angiogenic effects on HMVECs synergistically and in a dose-dependent manner.展开更多
AIM: To globally compare the gene expression profiles during the capillary morphogenesis of human microvascular endothelial cells (HMVECs) in an in vitro angiogenesis system with affymetrix oligonucleotide array.METHO...AIM: To globally compare the gene expression profiles during the capillary morphogenesis of human microvascular endothelial cells (HMVECs) in an in vitro angiogenesis system with affymetrix oligonucleotide array.METHODS: A microcarrier-based in vitro angiogenesis system was developed, in which ECs migrated into the matrix,proliferated, and formed capillary sprouts. The sprouts elongated, branched and formed networks. The total RNA samples from the HMVECs at the selected time points (0.5,24, and 72 h) during the capillary morphogenesis were used for microarray analyses, and the data were processed with the softwares provided by the manufacturers. The expression patterns of some genes were validated and confirmed by semi-quantitative RT-PCR. The regulated genes were grouped based on their molecular functions and expression patterns, and among them the expression of chemokines and chemokine receptors was specially examined and their functional implications were analyzed.RESULTS: A total of 1 961 genes were up- or downregulated two-folds or above, and among them, 468 genes were up- or down-regulated three-folds or above. The regulated genes could be grouped into categories based on their molecular functions, and were also clustered into six groups based on their patterns of expression. As for chemokines and chemokine receptors, CXCL1/GRO-α,CXCL2/GRO-β, CXCLS/ENA-78, CXCL6/GCP2, IL-8/CXCL8,CXCL12/SDF-1, CXCL9/Mig, CXC11/ITAC, CX3CL1/fractalkine,CCL2/MCP-1, CCL3, CCLS/RANTES, CCL7, CCL15, CCL21,CCL23, CCL28, and CCR1, CCR9, CXCR4 were identified.Moreover, these genes demonstrated different changing patterns during the capillary morphogenesis, which implied that they might have different roles in the sequential process. Among the chemokines identified, CCL2/MCP-1,CCL5/RANTES and CX3CL1 were specially up-regulated at the 24-h time point when the sprouting characterized the morphological change. It was thus suggested that they might exert crucial roles at the early stage of angiogenesis.CONCLUSION: The present study demonstrates a global profile of gene expression during endothelial capillary morphogenesis, and the results provide us much information about the molecular mechanisms of angiogenesis, with which further evaluation of individual genes can be conducted.展开更多
Orthorhombic LiMnO2 cathode materials were synthesized successfully at lower temperature by sol-gel method. When LiMnO2 precursor prepared by sol-gel method was fired in air, the product was a mixture of spinel struct...Orthorhombic LiMnO2 cathode materials were synthesized successfully at lower temperature by sol-gel method. When LiMnO2 precursor prepared by sol-gel method was fired in air, the product was a mixture of spinel structure LiMn2O4 and rock-salt structure Li2MnO3, whereas in argon single-phase orthorhombic LiMnO2 could obtain at the range of 750℃ to 920℃. The substitution of Mn by Zn2+ or Co3+ in LiMnO2 led to the structure of LiMnO2 transiting to Qα-LiFeO2. The results of electrochemical cycles indicated that the discharged capacity of orthorhombic-LiMnO2 was smaller at the initial stages, then gradually increased with the increasing of cycle number, finally the capacity stabilized to certain value after about 10th cycles. This phenomenon reveals that there is an activation process for orthorhombic LiMnO2 cathode materials during electrochemical cycles, which is a phase transition process from orthorhombic LiMnO2 to tetragonal spinel Li2Mn2O4. The capacity of orthorhombic LiMnO2 synthesized at lower temperature is larger than that synthesized at high temperature.展开更多
AIM: To investigate the potential role of cytokines in promoting Fas ligand (FasL)-expressing colon cancer cells.METHODS: Immunohistochemical SABC method was used to observe the expression of Fas receptor and ligand i...AIM: To investigate the potential role of cytokines in promoting Fas ligand (FasL)-expressing colon cancer cells.METHODS: Immunohistochemical SABC method was used to observe the expression of Fas receptor and ligand in SW620 colon cancer cell line and Jurkat T cells in order to provide the morphological evidence for the functions of Fas receptor and ligand. To examine the cytotoxicity of effector cells, CytoTox96(R) non-radioactive cytotoxicity assay was adopted to measure the lactate dehydrogenase-releasing value after SW620 cells were co-cultured with Jurkat T lymphocytes.RESULTS: The FasL of colon cancer SW620 cells was positive. The positive substances were distributed in the cell membrane and cytoplasm. The Fas receptor of colon cancer SW620 cells was negative. The Fas receptor and ligand of Jurkat T lymphocytes tumed out to be positive. The positive substances were distributed in the cell membrane.After phytohemagglutinin (PHA)-stimulated Jurkat T lymphocytes were co-cultured with phorbol 12-myristate 13-acetate (PMA)-plus-ionomycin-stimulated (for 48 h) SW620ceils or tumor necrosis factor-alpha (TNF-α)-stimulated (for 48 h) SW620 cells or unstimulated SW620 cells for 4 h,the cytotoxicity of SW620 cells to PHA-stimulated Jurkat cells at effector-to-target ratios of 10:1, 5:1, 2.5:1, and 1.25:1was 74.6%, 40.8%, 32.4%, and 10.9% (F= 8.19, P＜0.05);or 54.9%, 35.3%, 22.0%, and 10.3% (F= 11.12, P＜0.05);or 14.9%, 10.5%, 6.9%, and 5.8% (F= 3.45, P＜0.05).After PHA-stimulated Jurkat T lymphocytes were co-cultured with unstimulated SW620 cells for 8 h, the cytotoxicity of SW620 cells to PHA-stimulated Jurkat cells at effector-totarget ratios of 5:1, 2.5:1, and 1.25:1 from the experiment was 83.9%, 74.1%, and 28.5% (F= 137.04, P＜0.05)respectively. Non-radioactive cytotoxicity assay showed that the apoptotic rate of Jurkat cells remarkably increased with the increase of planting concentration of SW620 cells and co-culture time after the SW620 cells were co-cultured with the Jurkat T lymphocytes. The cytotoxicity was significantly enhancedby PMA+ionomycin or TNF-α.CONCLUSION: The FasL expressed in human colon cancer cells may be regulated by endogenous factors in the microenvironment of the host and facilitate the escape of tumor cells from the host immune system.展开更多
Experimental results are presented for superfluid (He Ⅱ) flow through porous plug liquid-vapor phase separators.Tests have been performed on seven porous plugs with different thicknesses or different permeabilities. ...Experimental results are presented for superfluid (He Ⅱ) flow through porous plug liquid-vapor phase separators.Tests have been performed on seven porous plugs with different thicknesses or different permeabilities. The temperature was measured from 1.5K to 1.9K. Two flow regions were observed in small and large pressure and temperature differences regions respectively. The experimental data are compared with theoretical predictions.The performance and applicability of the basic theory are discussed. Hysteresis of the flow rate is also observed and discussed.展开更多
文摘AIM: To develop an in vitro three-dimensional (3-D) angiogenesis system to analyse the capillary sprouts induced in response to the concentration ranges of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) and to quantify their synergistic activity.METHODS: Microcarriers (MCs) coated with human microvascular endothelial cells (HMVECs) were embedded in fibrin gel and cultured in 24-well plates with assay media. The growth factors bFGF, or VEGF, or both were added to the system. The wells (n = 8/group) were digitally photographed and the average length of capillary-like sprouts (ALS) from each microcarrier was quantitated.RESULTS: In aprotinin-stabilized fibrin matrix, human microvascular endothelial cells on the MCs invaded fibrin,forming sprouts and capillary networks with lumina. The angiogenic effects of bFGF or VEGF were dose-clependent in bhe range from 10 to 40 ng/mL. At d 1, 10 ng/mL of bFGF and VEGF induced angiogenesis with an ALS of 32.13±16.6 μm and 43.75±27.92 μm, respectively, which were significantly higher than that of the control (5.88±4.45 μm, P<0.01),and the differences became more significant as the time increased. In addition, the combination of 10 ng/mL of bFGF and VEGF each induced a more significant effect than the summed effects of bFGF (10 ng/mL) alone and VEGF (10 ng/mL) alone when analyzed using SPSS system for general linear model (GLM) (P= 0.011), and bhat also exceeded the effects by 20 ng/mL of either bFGF or VEGF.CONCLUSION: A microcarrier-based in vitro threedimensional angiogenesis model can be developed in fibrin.It offers a unique system for quantitative analysis of angiogenesis. Both bFGF and VEGF exert their angiogenic effects on HMVECs synergistically and in a dose-dependent manner.
文摘AIM: To globally compare the gene expression profiles during the capillary morphogenesis of human microvascular endothelial cells (HMVECs) in an in vitro angiogenesis system with affymetrix oligonucleotide array.METHODS: A microcarrier-based in vitro angiogenesis system was developed, in which ECs migrated into the matrix,proliferated, and formed capillary sprouts. The sprouts elongated, branched and formed networks. The total RNA samples from the HMVECs at the selected time points (0.5,24, and 72 h) during the capillary morphogenesis were used for microarray analyses, and the data were processed with the softwares provided by the manufacturers. The expression patterns of some genes were validated and confirmed by semi-quantitative RT-PCR. The regulated genes were grouped based on their molecular functions and expression patterns, and among them the expression of chemokines and chemokine receptors was specially examined and their functional implications were analyzed.RESULTS: A total of 1 961 genes were up- or downregulated two-folds or above, and among them, 468 genes were up- or down-regulated three-folds or above. The regulated genes could be grouped into categories based on their molecular functions, and were also clustered into six groups based on their patterns of expression. As for chemokines and chemokine receptors, CXCL1/GRO-α,CXCL2/GRO-β, CXCLS/ENA-78, CXCL6/GCP2, IL-8/CXCL8,CXCL12/SDF-1, CXCL9/Mig, CXC11/ITAC, CX3CL1/fractalkine,CCL2/MCP-1, CCL3, CCLS/RANTES, CCL7, CCL15, CCL21,CCL23, CCL28, and CCR1, CCR9, CXCR4 were identified.Moreover, these genes demonstrated different changing patterns during the capillary morphogenesis, which implied that they might have different roles in the sequential process. Among the chemokines identified, CCL2/MCP-1,CCL5/RANTES and CX3CL1 were specially up-regulated at the 24-h time point when the sprouting characterized the morphological change. It was thus suggested that they might exert crucial roles at the early stage of angiogenesis.CONCLUSION: The present study demonstrates a global profile of gene expression during endothelial capillary morphogenesis, and the results provide us much information about the molecular mechanisms of angiogenesis, with which further evaluation of individual genes can be conducted.
基金supported by the National Natural Science Foundation of China under grant No.59972026.
文摘Orthorhombic LiMnO2 cathode materials were synthesized successfully at lower temperature by sol-gel method. When LiMnO2 precursor prepared by sol-gel method was fired in air, the product was a mixture of spinel structure LiMn2O4 and rock-salt structure Li2MnO3, whereas in argon single-phase orthorhombic LiMnO2 could obtain at the range of 750℃ to 920℃. The substitution of Mn by Zn2+ or Co3+ in LiMnO2 led to the structure of LiMnO2 transiting to Qα-LiFeO2. The results of electrochemical cycles indicated that the discharged capacity of orthorhombic-LiMnO2 was smaller at the initial stages, then gradually increased with the increasing of cycle number, finally the capacity stabilized to certain value after about 10th cycles. This phenomenon reveals that there is an activation process for orthorhombic LiMnO2 cathode materials during electrochemical cycles, which is a phase transition process from orthorhombic LiMnO2 to tetragonal spinel Li2Mn2O4. The capacity of orthorhombic LiMnO2 synthesized at lower temperature is larger than that synthesized at high temperature.
基金Supported by the Science and Technology Commission Foundation of Tianjin, No. 003119711
文摘AIM: To investigate the potential role of cytokines in promoting Fas ligand (FasL)-expressing colon cancer cells.METHODS: Immunohistochemical SABC method was used to observe the expression of Fas receptor and ligand in SW620 colon cancer cell line and Jurkat T cells in order to provide the morphological evidence for the functions of Fas receptor and ligand. To examine the cytotoxicity of effector cells, CytoTox96(R) non-radioactive cytotoxicity assay was adopted to measure the lactate dehydrogenase-releasing value after SW620 cells were co-cultured with Jurkat T lymphocytes.RESULTS: The FasL of colon cancer SW620 cells was positive. The positive substances were distributed in the cell membrane and cytoplasm. The Fas receptor of colon cancer SW620 cells was negative. The Fas receptor and ligand of Jurkat T lymphocytes tumed out to be positive. The positive substances were distributed in the cell membrane.After phytohemagglutinin (PHA)-stimulated Jurkat T lymphocytes were co-cultured with phorbol 12-myristate 13-acetate (PMA)-plus-ionomycin-stimulated (for 48 h) SW620ceils or tumor necrosis factor-alpha (TNF-α)-stimulated (for 48 h) SW620 cells or unstimulated SW620 cells for 4 h,the cytotoxicity of SW620 cells to PHA-stimulated Jurkat cells at effector-to-target ratios of 10:1, 5:1, 2.5:1, and 1.25:1was 74.6%, 40.8%, 32.4%, and 10.9% (F= 8.19, P＜0.05);or 54.9%, 35.3%, 22.0%, and 10.3% (F= 11.12, P＜0.05);or 14.9%, 10.5%, 6.9%, and 5.8% (F= 3.45, P＜0.05).After PHA-stimulated Jurkat T lymphocytes were co-cultured with unstimulated SW620 cells for 8 h, the cytotoxicity of SW620 cells to PHA-stimulated Jurkat cells at effector-totarget ratios of 5:1, 2.5:1, and 1.25:1 from the experiment was 83.9%, 74.1%, and 28.5% (F= 137.04, P＜0.05)respectively. Non-radioactive cytotoxicity assay showed that the apoptotic rate of Jurkat cells remarkably increased with the increase of planting concentration of SW620 cells and co-culture time after the SW620 cells were co-cultured with the Jurkat T lymphocytes. The cytotoxicity was significantly enhancedby PMA+ionomycin or TNF-α.CONCLUSION: The FasL expressed in human colon cancer cells may be regulated by endogenous factors in the microenvironment of the host and facilitate the escape of tumor cells from the host immune system.
文摘Experimental results are presented for superfluid (He Ⅱ) flow through porous plug liquid-vapor phase separators.Tests have been performed on seven porous plugs with different thicknesses or different permeabilities. The temperature was measured from 1.5K to 1.9K. Two flow regions were observed in small and large pressure and temperature differences regions respectively. The experimental data are compared with theoretical predictions.The performance and applicability of the basic theory are discussed. Hysteresis of the flow rate is also observed and discussed.
