敏感性分析在新型农村合作医疗中的应斥——来自甘肃省灵台县的实证研究

敏感性分析，又称敏感度分析，它通过几个主要变量在一定范围内的变动，分析这种变动对结果带来的影响。运用敏感性分析的方法对灵台县新型农村合作医疗的住院统筹账户进行分析，发现次均住院费用、住院补偿率和补偿比例是影响新型农村合作医疗住院统筹账户平衡的主要因素，最后针对该县住院统筹账户运行现况提出相应的政策建议。     

Cation-pi interaction regulates ligand-binding affinity and signaling of integrin alpha4beta7

Integrin α(4)β(7) mediates rolling and firm adhesion of leucocytes, two of the critical steps in leukocyte migration and tissue specific homing. Affinity of α(4)β(7) for ligand is dynamically regulated by three interlinked metal ion-binding sites in β(7)-subunit I domain. In this study, we found that Phe185 (F185), a highly conserved aromatic residue in β(7)-subunit, links the specificity-determining loop and the synergistic metal ion-binding site (SyMBS) through cation-π interaction. Mutations of F185 that disrupted the SyMBS cation-F185 interaction led to deficient firm cell adhesion mediated by high affinity α(4)β(7), and only slightly affected rolling adhesion mediated by low affinity α(4)β(7). Disruption of SyMBS cation-F185 interaction induced partial extension of integrin ectodomain and separation of cytoplasmic tails, and impaired α(4)β(7)-mediated bidirectional signaling. In addition, loss of SyMBS cation-F185 interaction increased paxillin expression and promoted paxillin-integrin binding, leading to deficient cell spreading. Furthermore, integrin α(4)β(7)-mediated cell migration was decreased by the abolishment of SyMBS cation-F185 interaction. Thus, these findings reveal a cation-π interaction playing vital roles in the regulation of integrin affinity, signaling, and biological functions.