Molecular virology methods including polymerase chain reaction, cloning and sequencing have revolutionised our understanding of viral genome variation. In the case of hepatitis B virus (HBV), sequencing studies have i...Molecular virology methods including polymerase chain reaction, cloning and sequencing have revolutionised our understanding of viral genome variation. In the case of hepatitis B virus (HBV), sequencing studies have identified a number of virus variants normally found during the natural course of chronic infection. The appearance of the precore stop codon (with G-for-A substitution at position 1896) and basal core promoter (BCP) (with A-for-T and G-for-A, at positions 1762 and 1764, respectively) variants which reduce or abrogate hepatitis B e antigen (HBeAg) production, heralds the initiation of the seroconversion phase from HBeAg to anti-HBe positivity. The gradual removal of the tolerogenic effect of HBeAg leads to the awakening of the immune response (immune clearance phase). Most patients after HBeAg seroconversion become “inactive HBsAg carriers”. However during the course of infection precore and/or BCP variants may emerge and be selected leading to HBeAg negative chronic hepatitis B (CHB) with high viremia levels (reactivation phase). The prevalence of HBeAg negative CHB has been increasing over the last few decades and has become the commonest type of HBV infection in many countries of the world. This probably reflects the aging of existing HBV carriers and the effective prevention measures restricting new HBV infections. Frequent acute exacerbations accompanied by high viral replication, elevated alanine aminotransferase levels and histological activity are a common feature of HBeAg negative CHB leading to cirrhosis much faster than in HBeAg positive CHB patients.展开更多
目的 建立反相高效液相色谱法对五味子中的保留木脂素成分同时进行含量测定。方法 反相高效液相色谱法,色谱柱为Inertsil ODS-3 column(250 mm×4.6 mm i.d.,5μm),采用梯度洗脱的方式,流动相:A 甲醇,B 水。梯度洗脱:0-16 min VA : ...目的 建立反相高效液相色谱法对五味子中的保留木脂素成分同时进行含量测定。方法 反相高效液相色谱法,色谱柱为Inertsil ODS-3 column(250 mm×4.6 mm i.d.,5μm),采用梯度洗脱的方式,流动相:A 甲醇,B 水。梯度洗脱:0-16 min VA : VB=70:30,16-40 min VA:VB=100:0。结果 五味子中四种木脂素与周围未知成分达到基线分离,四种木脂素线形关系良好,相关系数r>0.999。结论 此法简单、灵敏、快速,为分析五味子及其相关制剂中主要单体木脂素提供了一种可行质量控制方法。展开更多
AIM: To validate whether the platelet count/spleen size ratio can be used to predict the presence of esophageal varices in Mexican patients with hepatic cirrhosis.
文摘Molecular virology methods including polymerase chain reaction, cloning and sequencing have revolutionised our understanding of viral genome variation. In the case of hepatitis B virus (HBV), sequencing studies have identified a number of virus variants normally found during the natural course of chronic infection. The appearance of the precore stop codon (with G-for-A substitution at position 1896) and basal core promoter (BCP) (with A-for-T and G-for-A, at positions 1762 and 1764, respectively) variants which reduce or abrogate hepatitis B e antigen (HBeAg) production, heralds the initiation of the seroconversion phase from HBeAg to anti-HBe positivity. The gradual removal of the tolerogenic effect of HBeAg leads to the awakening of the immune response (immune clearance phase). Most patients after HBeAg seroconversion become “inactive HBsAg carriers”. However during the course of infection precore and/or BCP variants may emerge and be selected leading to HBeAg negative chronic hepatitis B (CHB) with high viremia levels (reactivation phase). The prevalence of HBeAg negative CHB has been increasing over the last few decades and has become the commonest type of HBV infection in many countries of the world. This probably reflects the aging of existing HBV carriers and the effective prevention measures restricting new HBV infections. Frequent acute exacerbations accompanied by high viral replication, elevated alanine aminotransferase levels and histological activity are a common feature of HBeAg negative CHB leading to cirrhosis much faster than in HBeAg positive CHB patients.
文摘目的 建立反相高效液相色谱法对五味子中的保留木脂素成分同时进行含量测定。方法 反相高效液相色谱法,色谱柱为Inertsil ODS-3 column(250 mm×4.6 mm i.d.,5μm),采用梯度洗脱的方式,流动相:A 甲醇,B 水。梯度洗脱:0-16 min VA : VB=70:30,16-40 min VA:VB=100:0。结果 五味子中四种木脂素与周围未知成分达到基线分离,四种木脂素线形关系良好,相关系数r>0.999。结论 此法简单、灵敏、快速,为分析五味子及其相关制剂中主要单体木脂素提供了一种可行质量控制方法。
文摘AIM: To validate whether the platelet count/spleen size ratio can be used to predict the presence of esophageal varices in Mexican patients with hepatic cirrhosis.
