核苷酸结合寡聚化结构域1和2基因在幽门螺杆菌相关胃癌中的表达及意义

目的探讨核苷酸结合寡聚化结构域(NOD)1和2基因在幽门螺杆菌(Hp)相关胃癌患者中的表达变化及意义。方法采用免疫组织化学法检测胃癌患者癌组织中NOD1和NOD2蛋白的表达;采用实时聚合酶链反应(real-time PCR)检测胃癌组织中NOD1和NOD2 m RNA的表达;采用Western blot检测胃癌组织中凋亡蛋白核转录因子κB(NF-κB)和半胱氨酸的天冬氨酸蛋白水解酶3(Caspase-3)表达。结果与Hp阴性胃癌患者相比,Hp阳性胃癌患者癌组织中的NOD1和NOD2蛋白表达含量和m RNA表达含量上升;Hp阳性胃癌患者中的NF-κB和Caspase-3蛋白含量升高(P<0.05)。结论 Hp阳性胃癌患者中的NOD1和NOD2呈高表达状态;且过表达NOD1和NOD2可能在Hp阳性胃癌发生、发展机制中起重要的作用。

Heat shock protein 70 protects PC12 cells against ischemia-hypoxia/reoxygenation by maintaining intracellular Ca^(2+) homeostasis

Heat shock protein 70（HSP70） maintains Ca^2＋ homeostasis in PC12 cells,which may protect against apoptosis;however,the mechanisms of neuroprotection are unclear.Therefore,in this study,we examined Ca^2＋ levels in PC12 cells transfected with an exogenous lentiviral HSP70 gene expression construct,and we subsequently subjected the cells to ischemia-hypoxia/reoxygenation injury.HSP70 overexpression increased neuronal viability and ATPase activity,and it decreased cellular reactive oxygen species levels and intracellular Ca^2＋ concentration after hypoxia/reoxygenation.HSP70 overexpression enhanced the protein and m RNA expression levels of sarcoplasmic/endoplasmic reticulum Ca^2＋-ATPase（SERCA）,but it decreased the protein and m RNA levels of inositol 1,4,5-trisphosphate receptor（IP3R）,thereby leading to decreased intracellular Ca^2＋concentration after ischemia-hypoxia/reoxygenation.These results suggest that exogenous HSP70 protects against ischemia-hypoxia/reoxygenation injury,at least in part,by maintaining cellular Ca^2＋ homeostasis,by upregulating SERCA expression and by downregulating IP_3 R expression.

Thermal decomposition characteristics and kinetics of methyl linoleate under nitrogen and oxygen atmospheres

The thermal decomposition characteristics of methyl linoleate （ML） under nitrogen and oxygen atmo- spheres were investigated, using a thermogravimetric analyzer at a heating rate of 10 ~C/min from room tem- perature to 600℃. Furthermore, the pyrolytic and kinetic characteristics of ML at different heating rates were stud- ied. The results showed that the thermal decomposition characteristics of ML under nitrogen and oxygen atmo- spheres were macroscopically similar, although ML exhibited relatively lower thermal stability under an oxy- gen atmosphere than under a nitrogen atmosphere. The initial decomposition temperature, the maximum weight loss temperature, the peak decomposition temperature, and the rate of maximum weight loss of ML under an oxygen atmosphere were much lower than those under a nitrogen atmosphere and increased with increasing heating rates under either oxygen or nitrogen atmosphere. In addition, the kinetic characteristics of thermal decomposition of ML were elucidated based on the experimental results and by the multiple linear regression method. The activation energy, pre-exponential factor, reaction order, and the kinetic equation for thermal decomposition of ML were obtained. The comparison of experimental and calculated data and the analysis of statistical errors of pyrolysis ratios demonstrated that the kinetic model was reliable for pyrolysis of ML with relative errors of about 1%. Finally, the kinetic compensation effect between the pre-exponential factors and the activation energy in the pyrolysis of ML was also confirmed.