AIM： To investigate the impact of arachidonic acid （AA） and docosahexaenoic acid （DHA） and their combination on colon cancer cell growth. METHODS： The LS-174T colon cancer cell line was used to study the role of...AIM： To investigate the impact of arachidonic acid （AA） and docosahexaenoic acid （DHA） and their combination on colon cancer cell growth. METHODS： The LS-174T colon cancer cell line was used to study the role of the prostaglandin precursor AA and the omega-3 polyunsaturated fatty acid DHA on cell growth. Cell viability was assessed in XTT assays. For analysis of cell cycle and cell death, flow cytometry and DAPI staining were applied. Expression of cyclooxygenase-2 （COX-2）, p21 and bcl-2 in ceils incubated with AA or DHA was examined by real-time RT-PCR. Prostaglandin E2 （PGE2） generation in the presence of AA and DHA was measured using a PGE2- ELISA. RESULTS： AA increased cell growth, whereas DHA reduced viability of LS 174T cells in a time- and dosedependent manner. Furthermore, DHA down- regulated mRNA of bcl-2 and up-regulated p21. Interestingly, DHA was able to suppress AA-induced cell proliferation and significantly lowered AA-derived PGE2 formation. DHA also down-regulated COX-2 expression. In addition to the effect on PGE2 formation, DHA directly reduced PGE2-induced cell proliferation in a dosedependent manner. CONCLUSION： These results suggest that DHA can inhibit the pro-proliferative effect of abundant AA or PGE2.展开更多
Adsorption isotherm is the most fundamental information related to chromatography. To calculate the parameters of Langmuir ad-sorption isotherm of thymidine, frontal analysis (FA) and elution-curve method (ECM) were a...Adsorption isotherm is the most fundamental information related to chromatography. To calculate the parameters of Langmuir ad-sorption isotherm of thymidine, frontal analysis (FA) and elution-curve method (ECM) were adopted in reversed-phase high performance liguid chromatography (RP-HPLC). In FA, the concentration of stationary phase was measured from the elution curves and the isotherm was deter-mined by regression analysis, while the parameters by ECM were obtained by parameter optimization. The adsorption isotherms of thymidine from the two methods were very similar. The superiority of ECM over FA was that the consumption of sample was less and only one or two in-jections of sample were required.展开更多
Objective： To investigate the value of the plasma transforming growth factor β1 （TGF-β1） level in diagnosis and prognosis of prostate cancer （PCa）. Methods： The ELISA kits for human TGF-β1 were used to measur...Objective： To investigate the value of the plasma transforming growth factor β1 （TGF-β1） level in diagnosis and prognosis of prostate cancer （PCa）. Methods： The ELISA kits for human TGF-β1 were used to measure the TGF-β1 level in plasmas. A cohort of 295 consecutive PCa patients in recent more than two years in the First Hospital of Peking University of China was enrolled to the study. Furthermore, 55 control subjects were healthy and without evidence of PCa, who were random people that came to the hospital and were identified by prostate biopsy. Results： An age-related frequency chart indicated that 99% confidence interval of the difference with PCa was at the age of 53-85 years. The PCa patients aged 53-85 were classified into three groups according to TNM staging. Group A had Stages TO, T1 and T2. Group B had Stage T3 and Group C had Stage T4. Compared with control group, Group A had the lower level of plasma TGF-β1 （P 〈 0.05）, Group B had the higher level of plasma TGF-β1 （P 〈 0.05） and Group C had the even higher level of plasma TGF-β1 （P 〈 0.01）. According to TNM staging, Group D had Stages TO, T1 and T2 with the normal level of total PSA （tPSA）. Group E with the normal level of tPSA had metastasis after resection. Compared with control group, Group D had the lower plasma level of TGF-β1 （P 〈0.05） and Group E had higher plasma level of TGF-β1 （P 〈 0.01）. Conclusion： The plasma TGF-β1 level decreases at early stage of PCa and increases at later stage of PCa, especially at tumor metastasis after the resection. The plasma TGF-β1 level may therefore be complementary to PSA for PCa prognosis.展开更多
CO self-poisoning and slow surface kinetics pose major challenges to a CO oxidation catalyst that should work at ambient temperature.Furthermore,the presence of moisture would cause passivation of the catalyst A highl...CO self-poisoning and slow surface kinetics pose major challenges to a CO oxidation catalyst that should work at ambient temperature.Furthermore,the presence of moisture would cause passivation of the catalyst A highly active ceria promoted Pt catalyst（4%Pt-12%CeO_2/SiO_2;conversion≥99%at low（ 500 ppm） and high（ 2500 ppm） CO concentrations was developed for CO oxidation at ambient temperature in humid air.Catalyst preparation variables such as Pt and CeO_2 loading,ceria deposition method,drying and calcination conditions for the ceria and Pt precursors were optimized experimentally.The activity was correlated with surface properties using CO/H_2 chemisorption,O_2-H_2 titration,X-ray diffraction and BET surface area analysis.The method of CeO_2 deposition had a significant impact on the catalytic activity.CeO_2 deposition by impregnation resulted in a catalyst that was three times more active than that prepared by deposition precipitation or CeO_2grafting.O_2-H_2 titration results revealed that the close association of ceria and Pt in the case of CeO_2deposition by impregnation resulted in higher activity.The catalyst support used was also crucial as a silica supported catalyst was five times more active than an alumina supported catalyst.The particle size and pore structure of the catalyst support were also crucial as the reaction was diffusion controlled.The drying and calcination conditions of the ceria and Pt precursors also played a crucial role in determining the catalytic activity.The Pt-CeO_2/SiO_2 catalysts with Pt 2.5 wt%and CeO_2 15 wt%were highly active（TOF 0.02 s^（-1）） and stable（conversion 99%after 15 h） at ambient conditions.展开更多
基金Supported by Grants from the German National Academic Foundation (to P.H.)from the American Cancer Society (RSG-03-140-01-CNE)+2 种基金the NIH (NIH R01 113605) (both to J.X.K.)the German Research Foundation (DFG)a Charité Research Grant (both to K.H.W.)
文摘AIM： To investigate the impact of arachidonic acid （AA） and docosahexaenoic acid （DHA） and their combination on colon cancer cell growth. METHODS： The LS-174T colon cancer cell line was used to study the role of the prostaglandin precursor AA and the omega-3 polyunsaturated fatty acid DHA on cell growth. Cell viability was assessed in XTT assays. For analysis of cell cycle and cell death, flow cytometry and DAPI staining were applied. Expression of cyclooxygenase-2 （COX-2）, p21 and bcl-2 in ceils incubated with AA or DHA was examined by real-time RT-PCR. Prostaglandin E2 （PGE2） generation in the presence of AA and DHA was measured using a PGE2- ELISA. RESULTS： AA increased cell growth, whereas DHA reduced viability of LS 174T cells in a time- and dosedependent manner. Furthermore, DHA down- regulated mRNA of bcl-2 and up-regulated p21. Interestingly, DHA was able to suppress AA-induced cell proliferation and significantly lowered AA-derived PGE2 formation. DHA also down-regulated COX-2 expression. In addition to the effect on PGE2 formation, DHA directly reduced PGE2-induced cell proliferation in a dosedependent manner. CONCLUSION： These results suggest that DHA can inhibit the pro-proliferative effect of abundant AA or PGE2.
文摘Adsorption isotherm is the most fundamental information related to chromatography. To calculate the parameters of Langmuir ad-sorption isotherm of thymidine, frontal analysis (FA) and elution-curve method (ECM) were adopted in reversed-phase high performance liguid chromatography (RP-HPLC). In FA, the concentration of stationary phase was measured from the elution curves and the isotherm was deter-mined by regression analysis, while the parameters by ECM were obtained by parameter optimization. The adsorption isotherms of thymidine from the two methods were very similar. The superiority of ECM over FA was that the consumption of sample was less and only one or two in-jections of sample were required.
文摘Objective： To investigate the value of the plasma transforming growth factor β1 （TGF-β1） level in diagnosis and prognosis of prostate cancer （PCa）. Methods： The ELISA kits for human TGF-β1 were used to measure the TGF-β1 level in plasmas. A cohort of 295 consecutive PCa patients in recent more than two years in the First Hospital of Peking University of China was enrolled to the study. Furthermore, 55 control subjects were healthy and without evidence of PCa, who were random people that came to the hospital and were identified by prostate biopsy. Results： An age-related frequency chart indicated that 99% confidence interval of the difference with PCa was at the age of 53-85 years. The PCa patients aged 53-85 were classified into three groups according to TNM staging. Group A had Stages TO, T1 and T2. Group B had Stage T3 and Group C had Stage T4. Compared with control group, Group A had the lower level of plasma TGF-β1 （P 〈 0.05）, Group B had the higher level of plasma TGF-β1 （P 〈 0.05） and Group C had the even higher level of plasma TGF-β1 （P 〈 0.01）. According to TNM staging, Group D had Stages TO, T1 and T2 with the normal level of total PSA （tPSA）. Group E with the normal level of tPSA had metastasis after resection. Compared with control group, Group D had the lower plasma level of TGF-β1 （P 〈0.05） and Group E had higher plasma level of TGF-β1 （P 〈 0.01）. Conclusion： The plasma TGF-β1 level decreases at early stage of PCa and increases at later stage of PCa, especially at tumor metastasis after the resection. The plasma TGF-β1 level may therefore be complementary to PSA for PCa prognosis.
基金supported by US Army contract(W56HZV-05-C0686) at Auburn University administered through TARDEC
文摘CO self-poisoning and slow surface kinetics pose major challenges to a CO oxidation catalyst that should work at ambient temperature.Furthermore,the presence of moisture would cause passivation of the catalyst A highly active ceria promoted Pt catalyst（4%Pt-12%CeO_2/SiO_2;conversion≥99%at low（ 500 ppm） and high（ 2500 ppm） CO concentrations was developed for CO oxidation at ambient temperature in humid air.Catalyst preparation variables such as Pt and CeO_2 loading,ceria deposition method,drying and calcination conditions for the ceria and Pt precursors were optimized experimentally.The activity was correlated with surface properties using CO/H_2 chemisorption,O_2-H_2 titration,X-ray diffraction and BET surface area analysis.The method of CeO_2 deposition had a significant impact on the catalytic activity.CeO_2 deposition by impregnation resulted in a catalyst that was three times more active than that prepared by deposition precipitation or CeO_2grafting.O_2-H_2 titration results revealed that the close association of ceria and Pt in the case of CeO_2deposition by impregnation resulted in higher activity.The catalyst support used was also crucial as a silica supported catalyst was five times more active than an alumina supported catalyst.The particle size and pore structure of the catalyst support were also crucial as the reaction was diffusion controlled.The drying and calcination conditions of the ceria and Pt precursors also played a crucial role in determining the catalytic activity.The Pt-CeO_2/SiO_2 catalysts with Pt 2.5 wt%and CeO_2 15 wt%were highly active（TOF 0.02 s^（-1）） and stable（conversion 99%after 15 h） at ambient conditions.
