This study was supported by National Natural Science Foundation of China81000200;Beijing Health and Technical Personal of High level Plan2011-3-092;Basic-clinic Cooperative Foundation of Capital Medical University12JL28.国家自然科学基金81000200;北京市卫生系统高层次卫生技术人才培养项目2011-3-092;首都医科大学基础临床合作研究基金12JL28