In vitro growth, differentiation and biological characteristics of neural stem cells

OBJECTIVE： To summarize the biological characteristics of neural stem cells, and the separation, purification. differentiation and source of neural stem cells. DATA SOURCES ： An online search of Pubmed database was undertaken to identify English articles about the growth of neural stem cells in vitro published from January 2000 to October 2006 by using the keywords of ＂neural stem cells, bone marrow mesenchymal stem cells （BMSCs）, umbilical cord blood stem cells, embryonic stem cells （ESC）, separation methods, neural growth factor＂. And relevant articles published in IEEE/IEE Electronic Library （IEL） database, Springer Link database and Kluwer Online Journals were also searched, Chinese relevant articles published between January 2000 to October 2006 were searched with the same keywords in Chinese in Chinese journal full-text database. STUDY SELECTION ： The articles were primarily screened, and then the full-texts were searched. Inclusive criteria： （1） Articles relevant to the biological characteristics and classification of neural stem cells; （2） Articles about the source, separation and differentiation of the ESCs, BMSCs and umbilical cord blood stem cells. The repetitive studies and reviews were excluded. DATA EXTRACTION ： Thirty articles were selected from 203 relevant articles according to the inclusive criteria Articles were excluded because of repetition and reviews. DATA SYNTHESES ： Neural stem cells have the ability of self-renewing and high differentiation, and they are obtained from ESCs, nerve tissue, nerve system, BMSCs and umbilical cord blood stem cells. ESCs can be separated by means of mechanical dissociation is better than that of the trypsin digestion, BMSCs by density gradient centrifuge separation, hemolysis, whole-blood culture, etc., and umbilical cord blood stem ceils by Ficoil density gradient centrifugation, hydroxyethyl starch （HES） centrifugation sedimentation, etc. Neural growth factor （NGF） and other factors play an important role in the growth of NSCs, such as transforming growth factor （TGF） is an important player in repairing organs, NGF accelerates the process of growth, insulin-like growth factor serves importantly in the differentiation of stem cells into neuron-like cells. CONCLUSION ： As unipotent stem cells, NSCs have the abilities of self-renewal and potential of high differentiation. The method of mechanical dissociation is better than trypsin digestion in e separating ESCs. However, density gradient centrifuge separation is better than other methods in the separation of the BMSCs. NGF and other factors play an important role in the growth of NSCs.

Association between the related characters of hemispatial neglect and prognosis in stroke patients

OBJECTIVE： To recognize the significances of the classification, evaluation, treatment, pathogenesis, etiological factors and related loci of hemispatial neglect （HSN） in the treatment and prognosis of stroke patients. DATA SOURCES： Articles related to HSN in stroke published in English from January 1985 to December 2002 were searched in Medline database by using the keywords of ＂stroke, hemispatial neglect （HSN）, rehabilitation＂. Chinese relevant professional works and articles were also referred to. STUDY SELECTION： The data were primarily checked. Inclusive criteria： ① articles about the HSN symptoms in stroke; ② articles about the classification, evaluation, treatment, pathogenesis, etiological factors and related loci of HSN, as well as the treatment and prognosis of stroke. The repetitive studies or reviews were excluded. DATA EXTRACTION ： Totally 474 articles related to HSN in stroke were collected, 43 of them were involved and 431 repetitive studies or reviews were excluded. DATA SYNTHESES： HSN can be classified as sensory neglect and motor neglect. Because HSN is caused by the injury of network structure which mediated directed attention, it is generally believed that the inferior parietal Iobule of dominant hemisphere is the most closely correlated with neglect. The main theories related to the pathogenesis of HSN at present include ＂internal instruction＂, ＂directed bradykinesia＂, ＂sensory attention＂, etc. The main clinical manifestations are setover in drawing lines, picture drawing towards one side, imitation towards one side, picture description towards one side, etc., which can be evaluated by the line bisection test, target cancellation test, picture drawing test and pegboard test. The most important thing for the treatment is to make the patients continuously concentrate on the neglected side. CONCLUSION： HSN is an indicator for the bad outcome of cerebrovascular disease, the symptoms take longer time to rehabilitate with slow recovery, but quite a few HSN patients will get good prognosis if timely treatment and proper program are given.