Objective To investigate the effect of immunocompetent cells and immune regulator on the apoptosis of human mesenchymal stem cells ( MSCs) and on mRNA expression of heme oxygenase-1. Methods MSCs were cultured by density gradient centrifugation and then identified by flow cytometry. RT-PCR was used to detect HO-1 mRNA expression and flow cytometry was used to analyze cell apoptosis after the stimulation of IFN-? and PHA-activated T cells. Results The mRNA expression of Heme oxygenase-1 was observed in MSCs and decreased after the stimulation of IFN-? and activated T cells. IFN-?,znpp-Ⅸ and combined these two caused obvious cell apoptosis in MSCs,with an apoptotic rate of ( 56. 50 ? 0. 16) % ,( 56. 85 ? 2. 27) % ,and ( 82. 53 ? 2. 65) % respectively. All of them had a significant difference compared with the normal MSCs [( 7. 56 ? 1. 43) % ,P

To develop a low-cost, reliable, easy-to-maintain and practical instrument for protein purification. Some ultraviolet luminescent diode was used to provide 280 nm light source, and high-sensitivity S1336 photo-electric detector was employed for real-time monitoring of purified protein solution flowing through quartz cell to supervise the concentration of the protein. The instrument gave voice alarm and stopped working in case the protein concentration was less than the standard one. The lower SCM monitored the liquid level of the protein collecting cup and the position of loading arm through laser infrared distance sensor, so that a cup full of protein might be replaced by another empty cup. The instrument involved in Samsung S5PV210 embedded master computer, Wince6.0 operating system, Keil4.0 and VS2005. Trials proved that the instrument could perform real-time monitoring and curve display of dual-channel ultraviolet absorption, and could realize auto collection of 735 ml protein solution and up to 5-hour standby. The instrument developed has simple structure, high reliability and easy maintenance, and meets the desired require-ments.