Objective Investigation of biological characteristics of Cdc 20AAA/+APCmin/+ mouse embryonic fibroblast(MEFs) indicate the effect of Cdc20AAA/+on growth of mouse embryonic fibroblast and the possible mechanism . Methods MEFs of Cdc20AAA/+APCmin/+, Cdc20AAA/+, APCmin/+ and WT genotype were harvested from embryos for analysis.The growth characteristics of Cdc20AAA/+APCmin/+, Cdc20AAA/+,APCmin/+and WT mouse embryonic fibroblast were analyzed through growth curve analysis and foci formation assay .Separation of sister chromatid and the presence of aneuploid were detected by karyotype analysis .Results Cell proliferation assays showed that Cdc 20AAA/+APCmin/+cells grew at an accelerated rate compared with APC min/+MEFs(P<0.01).Foci formation assay showed that the clone forming ability was significantly increased .Cdc20AAA/+APCmin/+MEFs showed a significant increase in the frequency of aneuploid compared with WT MEFs , which had a karyotype of 38 and contained prematurely separated sister chromatids .Conclusion Cdc20 carrying a null allele (Cdc20AAA/+) may accelerate the growth and proliferation of APC min/+MEFs and present the growth characteristics of the tumor cells .The possible mechanism may be associated with chromosome instability .

With the development of the health service in china,the old talent-training program for clinical medicine major was failed in meeting higher demands for talents of clinical medicine. To create the new talent-training program,therefore,has become the main content of teaching reform for medical col-leges and universities. Taking University of South China as an example,the paper analyzed the changing trend of talent-training program for five-year clinical medicine majors from talent-training goal,curriculum system,practical teaching and content of courses,which proposed some thoughts on the optimization of training program for clinical medicine majors.