Objective To study the phenomena and the related mechanisms of malignant transformation of dermis derived multipotential stem cells in vitro . Methods Clonal populations of dermal multipotential stem cells were passaged sequentially in vitro , and the subcutaneous inoculation of cells in nude mice was used for observation of the tumor formation. The transcript profiles of the transformed cells were analyzed by DNA microarray technique. Results Dermal multipotential stem cells underwent spontaneous malignant transformation after serial subculture in vitro . Cells grew out of control, and chromosome number was abnormal. After cells were inoculated subcutaneously into BALB/c nu/nu athymic mice, tumors characterized by fibrous histiocytoma were produced. Immunohistochemistry showed that there were different cell populations for the expression of vimentin, cytokeratin, S 100, and ? smooth actin. Detection by DNA microarray technique revealed that the transformed cells expressed multilineage transcripts, indicating that the transformed cells might have the multipotency. Among the differentially expressed genes in transformed cells, most of the up regulated genes were related to the proliferation process, but most of the down regulated genes were growth factors and their receptors. The enhanced expression of the c ki ras gene and its relevant molecules may play important roles in the transformation process. A candidate gene with unknown functions related to the stem cell proliferation was also preliminarily identified. Conclusion Dermal multipotential stem cells can undergo spontaneous malignant transformation in vitro . Further studies of the mechanisms of this process at the molecular level may have significance both in stem cell application and in tumorigenesis.

Information-based teaching was applied in the experimental teaching of nuclear protection medicine based on its own features.The teaching content was sent to students as micro-video via an information platform before class for preview;during the class,the teaching was performed in the form of lectures by students and experiments in groups;after class,students were required to submit reports of experimental improvement or innovative experimental design.A comprehensive assessment was performed for preview,classroom operation,question answering in class,and experimental reports.The results of teaching practice showed that this teaching mode can effectively stimulate the students' interests in learning,enhance their research and innovation abilities,and improve the experimental teaching effect of nuclear protection medicine.

OBJECTIVE To explore the changes in chemical compositions and the characteristics of “fried charcoal and saving properties” based on the carbon-frying process of Sophora japonica and its bud. METHODS The slightly， moderately and heavily carbon-fried samples of S. japonica and its bud were prepared. The fingerprints of S. japonica， its bud and carbon-fried samples were established， and common peaks were identified. HPLC method was used to determine the contents of identified components and differential analysis was also performed； the differential components were screened by using chemometric methods， and their content ratios were used to characterize the “fried charcoal and saving properties” of S. japonica and its bud. RESULTS There were 9 common peaks in the fingerprints of S. japonica and its carbon-fried samples， 8 common peaks in those of S. japonica bud and its carbon-fried samples. In the fingerprints of S. japonica and its bud， and their different fried products， 6 components were identified， such as rutin， kaempferol-3-O-rutinoside， isorhamnetin-3-O-rutinoside， quercetin， kaempferol，isorhamnetin. Among them， the contents of rutin， kaempferol-3-O-rutinoside and isorhamnetin-3-O-rutinoside were the highest in slightly carbon-fried samples of S. japonica bud， and the contents of quercetin and isorhamnetin were the highest in moderately carbon-fried samples of S. japonica bud， and the contents of kaempferol were higher in moderately and healily carbon-fried samples of S. japonica bud. The chemometric results showed that the variable importance projection values of rutin and quercetin were both greater than 1. The range of rutin-quercetin content ratio between 9.00-14.00 and 3.00-6.00 respectively could characterize “fried charcoal and saving properties” of S. japonica and its bud. CONCLUSIONS There are significant differences in the chemical compositions of raw and fried products of S. japonica and its bud. Rutin and quercetin may be the differential components that affect their quality， and the ratio range of the two can be used to characterize the “fried charcoal and saving properties” of S. japonica and its bud in the future.