一个病毒传染模型的稳定性

研究一个具有溶免疫反应的病毒传染病模型的全局稳定性。若凡≤1（凡表示病毒基本再生率），则无疾病稳定点是全局渐近稳定的；若1〈民〈C（C为常数），则免疫系统破坏；若R0〉c，则发生地方流行病。     

Evidence for hydrogen-deuterium exchange in viral particles

Heavy water (D2O) could enhance thermostability of some viruses. However, the underlying mechanism is not clear. Here we report the development of a matrix-aided gas-isotope-ratio mass spectrometry method that allows direct determination of deuterium/hydrogen (D/H) ratio in D2O-treated Japanese encephalitis virus (JEV), hepatitis A virus (HAV) and RNA from D2O-treated HAV. The D/H ratiowas expressed as δDSMOW. Our experiments showed that δDSMOW values increased significantly in D2O-treated viral samples compared to normal controls, and increment in δDSMOW of D2O, treated viral samples was in a fine linear relationship with increment in amount of samples loaded in BSA matrix. Our experiments also indicated that increased δDSMOW of D2O-treated virus correlated well with its enhanced thermostability. The results suggested that hydrogen-deuterium exchange occurred in viral particles and its RNA structure as a result of D2O-treatment. Furthermore,such exchange could cause changes in viral phenotype, such as enhanced thermostability.     

网络视频病毒式营销探析

通过对《旱冰宝宝》网络视频引起的病毒式营销事件,以问卷调研的形式进行实证分析,探讨网络视频病毒式营销.对病毒式营销的概念和原理进行了界定,将其与电视广告等传统营销形式进行对比,挖掘出病毒式营销的特点,结合《旱冰宝宝》案例分析了网络视频病毒式营销获得良好广告效应的传播过程.通过对消费者进行体验式问卷调研的实证方法,运用因...     

Creep effect on cellular uptake of viral particles

Receptor diffusion on cell membrane is usually believed as a major factor that controls how fast a virus can enter into host cell via endocytosis. However, when receptors are densely distributed around the binding site so that receptor recruiting through diffusion is no longer energetically favorable, we thus hypothesize that another effect, the creep deformation of cytoskeleton, might turn to play the dominant role in relaxing the engulfing process. In order to deeply understand this mechanism, we propose a viscoelastic model to investigate the dynamic process of virus engulfment retarded by the creep deformation of cytoskeleton and driven by the binding of ligand-receptor bonds after overcoming resistance from elastic deformation of lipid membrane and cytoskeleton. Based on this new model, we predict the lower bound of the ligand density and the range of virus size that allows the complete engulfment, and an optimal virus size corresponding to the smallest wrapping time. Surprisingly, these predictions can be reduced to the previous predictions based on simplified membrane models by taking into account statistical thermodynamic effects. The results presented in this study may be of interest to toxicologists, nanotechnologists, and virologists.     

Virus-induced autoantibody response to a transgenic viral antigen

The induction of autoantibodies and their possible role in the pathogenesis of autoimmune disease are poorly understood. Involvement of infectious agents has been suspected, but direct evidence is sparse. Whether immunological unresponsiveness to self by antibody-forming B cells is maintained by clonal abortion, clonal anergy or suppression, or how the scenario of interactions between helper T cells, B cells and antigen-presenting cells is distorted in autoantibody responses, is being analysed and widely debated. To evaluate tolerance of neutralizing B-cell responses we used transgenic mice expressing the cell membrane associated glycoprotein (G) of vesicular stomatitis virus (VSV) as self-antigen. We show that autoantibodies to VSV-G cannot be induced by VSV-G in adjuvant or by recombinant vaccinia virus expressing VSV-G, but are triggered by infection with wild-type VSV. The data show that helper T-cell tolerance is crucial in maintenance of B-cell non-reactivity and that cognate T-B recognition is necessary to break tolerance of self-reactive B cells. These results may help to understand mechanisms of virus-induced autoimmunity.     

1,6-二磷酸果糖治疗儿童病毒性心肌炎的疗效观察

针对湘雅医院1996年至1998年经临床确诊的38例儿童病毒性心肌炎，予以1，6—二磷酸果糖治疗。揭示出：该药能明显缩短病程，且简单易行无明显不良反应，值得临床应用。