The SEIR epidemic model studied here includes constant inflows of new susceptibles, exposeds, infectives, and recovereds. This model also incorporates a population size dependent contact rate and a disease-related dea...The SEIR epidemic model studied here includes constant inflows of new susceptibles, exposeds, infectives, and recovereds. This model also incorporates a population size dependent contact rate and a disease-related death. As the infected fraction cannot be eliminated from the population, this kind of model has only the unique endemic equilibrium that is globally asymptotically stable. Under the special case where the new members of immigration are all susceptible, the model considered here shows a threshold phenomenon and a sharp threshold has been obtained. In order to prove the global asymptotical stability of the endemic equilibrium, the authors introduce the change of variable, which can reduce our four-dimensional system to a three-dimensional asymptotical autonomous system with limit equation.展开更多
AIM： To identify the role of herbal compound 861 （Cpd 861） in the regulation of mRNA expression of collagen synthesis- and degradation-related genes in human hepatic stellate cells （HSCs）. METHODS： mRNA levels o...AIM： To identify the role of herbal compound 861 （Cpd 861） in the regulation of mRNA expression of collagen synthesis- and degradation-related genes in human hepatic stellate cells （HSCs）. METHODS： mRNA levels of collagen types I and III, matrix metalloproteinase 1 （MMP-1）, matrix metalloproteinase 2 （MMP-2）, membrane type-1 matrix metalloproteinase （MT1-MMP）, tissue inhibitor of metalloproteinase 1 （TIMP-1）, and transforming growth factor β1 （TGF-β1） in cultured-activated HSCs treated with Cpd 861 or interferon-γ, （IFN-γ,） were determined by real-time PCR. RESULTS： Both Cpd 861 and IFN-γ reduced the mRNA levels of collagen type Ⅲ, MMP-2 and TGF-β1. Moreover, Cpd 861 significantly enhanced the MMP-1 mRNA levels while down-regulated the TIMP-1 mRNA expression, increasing the ratio of MMP-1 to TIMP-1 to （6.3 ＋ 0.3）- fold compared to the control group. CONCLUSION： The anti-fibrosis function of Cpd 861 may be mediated by both decreased interstitial collagen sythesis by inhibiting the transcription of collagen type Ⅲ and TGF-β1 and increased degradation of these collagens by up-regulating MMP-1 and down-regulating TIMP-1 mRNA levels.展开更多
基金This research is supported by the NNSF of China (19971066)
文摘The SEIR epidemic model studied here includes constant inflows of new susceptibles, exposeds, infectives, and recovereds. This model also incorporates a population size dependent contact rate and a disease-related death. As the infected fraction cannot be eliminated from the population, this kind of model has only the unique endemic equilibrium that is globally asymptotically stable. Under the special case where the new members of immigration are all susceptible, the model considered here shows a threshold phenomenon and a sharp threshold has been obtained. In order to prove the global asymptotical stability of the endemic equilibrium, the authors introduce the change of variable, which can reduce our four-dimensional system to a three-dimensional asymptotical autonomous system with limit equation.
文摘AIM： To identify the role of herbal compound 861 （Cpd 861） in the regulation of mRNA expression of collagen synthesis- and degradation-related genes in human hepatic stellate cells （HSCs）. METHODS： mRNA levels of collagen types I and III, matrix metalloproteinase 1 （MMP-1）, matrix metalloproteinase 2 （MMP-2）, membrane type-1 matrix metalloproteinase （MT1-MMP）, tissue inhibitor of metalloproteinase 1 （TIMP-1）, and transforming growth factor β1 （TGF-β1） in cultured-activated HSCs treated with Cpd 861 or interferon-γ, （IFN-γ,） were determined by real-time PCR. RESULTS： Both Cpd 861 and IFN-γ reduced the mRNA levels of collagen type Ⅲ, MMP-2 and TGF-β1. Moreover, Cpd 861 significantly enhanced the MMP-1 mRNA levels while down-regulated the TIMP-1 mRNA expression, increasing the ratio of MMP-1 to TIMP-1 to （6.3 ＋ 0.3）- fold compared to the control group. CONCLUSION： The anti-fibrosis function of Cpd 861 may be mediated by both decreased interstitial collagen sythesis by inhibiting the transcription of collagen type Ⅲ and TGF-β1 and increased degradation of these collagens by up-regulating MMP-1 and down-regulating TIMP-1 mRNA levels.
