BACKGROUND:Some studies show that basic fibroblast growth factor(bFGF)strongly expresses dudng the process of embryonic stem cells differentiation into hematopoietic stem cell.yolk sac blooding.and fetal liver hematopoiesis.OBJECTIVE:To study the regulation of bFGF on the blast-colony-forming cell(BL-CFC)by adding bFGF in the medium of embryoid body generation.METHODS:The third to fifth generations of the pdmaw mouse embryonic fibroblasts were recovered,and then incubated with the DMEM medium containing mitomvcin C for 2.5 hours in order to lose the proliferative capacity.Then cells were suspended into single cell by trypsinization and inoculated in the gelatin-coated bottle at the density of 10×104/cm2.After culturing for 24 hours,mouse embryonic stem cells(mESC)of D3 were recovered and placed on the feeder layer cells.According to the composition of medium in embryoid body generation.mESCs were divided into two groups:group A:standard medium+VEGF+SCF;group B:standard medium+VEGF+SCF+bFGF.Each group was cultured for 3 days and 6 days respectively,and the cloning number of BL-CFC was quantified,as well as Flk-1+ expression was observed by immunofluorescence staining.Positive number and average absorbance were analyzed using IMAGE-PRO PLUS imaging analysis system.RESULTS AND CONCLUSION:Adding bFGF in the course of embryoid body growth could significantly increase the number of BL-CFC(P＜0.01).and the positive results of Flk-1 and the average absorbance were also increased significantly(P＜0.01).bFGF effectively promoted embryoid body amplification and proliferation of BL-CFC.

BACKGROUND: There are small amount of hematopoietic stem cells, which are easy to divide in vitro and show the difficulty in applying to transplantation.OBJECTIVE: This paper has focused on the role and means of the Wnt, Notch, Bmi_1, Shh, HOXB4 signaling molecule in the maintenance of hematopoietic stem cell self-renewal and regulation. METHODS: With the key words of "HSC, Wnt, Notch, Bmi_1, Shh, HOXB4" for the search, we searched PubMed database (2002-01/2008-12) in English. Literatures closely related to the hematopoietic stem cell self-renewal related signaling molecules were included. Repetitive research and Meta analysis were excluded.RESULTS AND CONCLUSION: The computer initially retrieved 216 documents, of which 30 documents for research. Hematopoietic stem cells are self-renewing, have strong differentiation and growth and regeneration capacities, can produce various types of blood cells ancestor cells, are widely used to treat blood diseases, but the hematopoietic stem cell differentiation in vitro demonstrated that the difficulties used in transplantation. How to make hematopoietic stem cells in vitro amplification and processing, while maintaining hematopoietic stem cell self-renewal characteristics is of a key issue. In recent years, different signaling pathways to enhance the ability of hematopoietic stem cell self-renewal signaling molecule have been a research hotspot. The article focused on the role and means of the Wnt, Notch, Bmi_1, Shh, HOXB4 in the maintenance of hematopoietic stem cell self-renewal and regulation and found that both the above-mentioned five signaling molecules can enhance hematopoietic stem cell self-renewal function. There are also a number of factors playing an important role in the maintenance of hematopoietic stem cell self-renewal process, such as endogenous factors, a series of transcription factors Oct-4, Ehox, Nanog, SCL, Runx1 and so on, to explore how their regulatory networks formed by the interaction control self-renewal of hematopoietic stem cells will become a key point in the research of self-renewal of hematopoietic stem cells.

Objective To further explore the mechanism by which bone morphogenetic protein 4(BMP-4)might be involved in hematopoietic differentiation of the yolk sac.We observed the expression of BMP-4,CD34,CD133 and tyrosine kinase receptors(KDR) in the blood island of the yolk sac at embryonic 3 to 8 weeks.Methods Gene expression was analyzed by RT-PCR and the presence of BMP-4,CD34,CD133 and KDR proteins was confirmed by immunohistochemistry in 57 human embryos.Results In the human yolk sac,we found that BMP-4 was expressed at high levels from the 16th day to the 7th week,and decreased quickly after week 7.The results showed that KDR,CD133 and CD34 largely appeared on the 21st and 30th day,then increased at the 6th week,and decreased quickly after week 7.Furthermore,Ihh,SCl,GATA-1,GATA-2 and PU.1 mRNAs showed that PU.1 was not expressed on the 16th day;however,other factors were expressed all the time.Conclusion The distribution of BMP-4,KDR,CD34,CD133 and transcription factors expression highly suggested that BMP-4 was secreted from the yolk sac which might exert its effects on the specification of human hemangioblast and hematopoietic stem cells from the embryonic mesoderm in vivo through transcription factors.

Research articles in the domestic bilingual teaching on the basis of the status, and presents a stratification analysis of thinking methods,to explore the notion of bilingual teach-ing,and the hierarchical structure of teacher,teaching materials,students,and evaluation of the bilingual teaching,and probe into the reform of bilingual teaching.

Objective The expression of hematopoietic stem cell and neural markers on placenta adherent cells and their association were investigated, the potential of neural differentiation of placenta adherent cells may demonstrate the relationship between placenta adherent cells and hematogenesis and neurogenesis. Methods Isolated adherent cells in human placenta tissue were stained immunocytochemically with Nestin, MAP_2, MBP, CD133, CD34 antibody to detect protein production and induced neural differentiation with β-mercaptoethanol and retinoic acid. Results Isolated placenta adherent cells confirmed to be heterogenous expressed CD133, Nestin, MAP_2 weakly and CD34 none. While induced cells showed neural like morphology, strong positive for Nestin, MAP_2 and weak positive for MBP and GFAP in immunocytochemical staining. Conclusion Human placenta adherent ceils can be induced into neural like cells in vitro with histological characteristics of mesenchymal stem cell(MSC) ,it provides a new source for clinical application of hMSCs.

Objective The expression of hematopoietic stem cell and neural markers on placenta adherent cells and their association were investigated,the potential of neural differentiation of placenta adherent cells may demonstrate the relationship between placenta adherent cells and hematogenesis and neurogenesis.Methods Isolated adherent cells in human placenta tissue were stained immunocytochemically with Nestin,MAP2,MBP,CD133,CD34 antibody to detect protein production and induced neural differentiation with ?-mercaptoethanol and retinoic acid.ResultsIsolated placenta adherent cells confirmed to be heterogenous expressed CD133,Nestin,MAP2 weakly and CD34 none.While induced cells showed neural like morphology,strong positive for Nestin、MAP2 and weak positive for MBP and GFAP in immunocytochemical staining.Conclusion Human placenta adherent cells can be induced into neural like cells in vitro with histological characteristics of mesenchymal stem cell(MSC),it provides a new source for clinical application of hMSCs.

Objective:To study the regulation of MSCs on the asthma;and to observe the expression of Notch signal in lung tissue of asthmatic rats.Methods:30 rats were randomly divided into 3 group :normal control group , asthma model group and MSC transplantation group.Making paraffin sections of lung tissue for pathological examination ,quantitative real-time PCR(RT-PCR) were used to identify the expression of Notch2 and Jagged1 mRNA in the rat lung tissue,and the expression of Notch2,Jagged1 were measured by Western blot.Results:Compared with normal control group and MSC transplantation group ,inflammatory cell infiltration and narrower airway were observed in asthma model group .The lever of Notch2,Jagged1 in asthma model group was higher than MSC transplantation group and normal control group ( P<0.05 ).Conclusion:Mesenchymal stem cells can affect the expression of the Notch signaling pathway in asthmatic rats ,and play a role in the treatment of asthma.