Stem cells in bone marrow are considered as an ideal sources of seed cells with the advantage of being isolation and easy proliferated in vitro,which is a prerequisite for the autotransplantation. Studies show that the cells can differentiate into neurons. However,this opinion challenges the traditional conception of cell differentiation and therefore the dispute arises. Here we review the results of research on dedifferentiation of bone marrow cells.

OBJECTIVE To explore study a method for rapid detection of bacterial infection in clinic to diagnose septicemia early.METHODS 16S rRNA gene of ten bacterial species was amplified with PCR,by using human genome DNA,HBV-DNA and Candida albicans as comparison.The sensitivity test was done by the method of gradual dilution of Escherichia coli.RESULTS The bacterial species were amplified and the products were 371 bp,but human genome DNA,HBV-DNA and C.albicans showed no amplification products.Sensitivity test showed that it could detect as low as 1.5?104/L of E.coli.CONCLUSIONS The method is rapid and highly specific and sensitive in detecting the existence of bacterial 16S rRNA gene.

OBJECTIVE To set up a quick method to detect pathogens in cerebrospinal fluid.METHODS The method of polymerase chain reaction(PCR),using a pair of universal primers targeted at the 16S rRNA gene,was adopted to amplify the DNA of bacterium.138 clinical specimens obtained from patients were examined by PCR method and bacterial culture method.RESULTS The positive rate was 39.86% of PCR and 17.39% of culture,the outcomes had statistical significance(P