Comparison in effect of different metal ions, pH and reducing agent on the protease activity in human hyper mature and mature cataract

This study was undertaken to isolate and characterize the protease activity of human eye lens sample of mature and hyper mature cataract. Samples were collected just after surgery of the cataract lens and were stored at -20 ℃. The total protein extract was isolated from 5 samples in each case （mature and hyper mature cataract） and clear supernatant obtained after centrifugation was used as an enzyme source. The optimum pH for the proteases of mature cataract was 7.5 while the proteases of hyper mature cataract were recorded for maximum activity at pH 5.5 and 7.5. The optimum temperature for both enzyme sources was 50 ℃. Effect of different metal ions such as potassium, lead, silver, zinc and borate was studied. In each case protease activity was increased. Reducing agent e.g. β mercaptoethanol also caused an increase in activity indicating the involvement of sulfhydryl groups. Protease activity was also located on agar plates.

人骨髓基质细胞向神经元分化的两种体外诱导方法比较

目的通过体外定向诱导人骨髓基质细胞(hBMSCs)使其分化为神经元,比较两种诱导方法。方法采用Percoll-Paque液(1.073g/ml)分离hBMSCs,体外扩增培养后,分别加入丁羟茴醚(BHA)+二甲基亚砜(DMSO)和β-巯基乙醇(BME)诱导hBMSCs分化为神经元,光镜下形态学观察,及免疫组化检测特异性神经元烯醇化酶(NSE),神经丝蛋白(NF),胶质纤维酸性蛋白(GFAP)阳性细胞数。结果hBMSCs在加入两种诱导剂后均有胞体收缩,突起伸出,NSE,NF,GFAP均有不同程度阳性率,但丁羟回醚+二甲基亚酚组的细胞存活率高,神经元阳性率(诱导成功率)高。结论丁羟茴醚+二甲基亚酚是一种较好的体外诱导hBMSCs分化为神经元的诱导剂。