OBJECTIVE: To prove that the neural stem cell can be separated from neural tissue in adult mammalian. Stem cells can separate and proliferate continually, and can divide further into neuron and glial cell. The uptodate researches of neural stem cells suggest a prospective approach to treat neurological diseases, i.e. the dysfunctional cells may be replaced with neural stem cells by transplantation for functional reconstruction. Therefore,many kinds of directional differentiative signal controlling of neural stem cells to differentiate at a certain direction.DATA SOURCES: Using the key term neural stem cell, differentiation,signal and cell transplantation, we searched the MEDLINE database plus the relevant articles in English language from January 1995 to August 2004. Meanwhile, using the key terms mentioned above, we searched Chinese journal full-text database, Wanfang database in Chinese language from January 1995 to August 2004.STUDY SELECTION: The articles on extracellular signal of the differentiation of neural stem cell with full summarization were selected.DATA EXTRACTION: A total of 30 articles were eligible, and the relevant contents were compared and summarized. Eighteen articles were selected at last.DATA SYNTHESIS: All 18 articles contained different aspects of signal regulation of neural stem cell, including various key cellular factors and autogene regulation.CONCLUSION: Both cellular signals in vivo and in vitro can affect the cell differentiation. The vital problem to be solved is how to induce neural stem cells to differentiate at a certain direction so as to realize the aim of transplantation.

Objective To explore the role of tissue-type plasminogen activator(tPA) in neonatal rat with hypoxia-ischemia brain damage(HIBD).Methods Seven-day-old Wistar rat pups were used for the Vannucci model of HIBD.Reverse transcription-polymerase chain reaction(RT-PCR),terminal deoxynucleotidyl transferase mediated dUTP nick end labeling(TUNEL),double immunostaining and immunoblot analysis were adapted to determin the expression of tPA at acute phase after HIBD and neural cell apoptosis and the blood-brain-barrier(BBB) damage.Results Neonatal hypoxia-ischemia triggers persistent induction of the plasminogen system.The increase of tPA activity induced the degradation of laminin and occludin which would aggravate the BBB damage.The number of neural cell apoptosis after HIBD increased progressively with the reperfusion time.Conclusions The increase of tPA at the acute phase after HIBD can help clot to dissolve,while its extravascular proteolysis will induce cell apoptosis and BBB damage which will aggravate brain injury.

Female ; Humans ; Hyperthyroidism ; drug therapy ; etiology ; Infant, Newborn ; Male

Objective To investigate whether exogenic brain derived neurotrophic factor (BDNF) can permeate placental barrier into fetus and further through fetal blood brain barrier(BBB) after transient ischemia. Methods Seventeen day pregnant rats were selected. The uterine arteries of the rats were clamped for 30 minutes in experimental group. BDNF labeled with 125 I was injected into the rats through caudal veins. The radioactivity of BDNF in different fetal organs was measured at 24 h, 48 h and 72 h. Results 125 I BDNF was detected in amniotic fluid, placenta and fetal organs including brain, heart, lung, liver and kidney. This indicated that BDNF partly permeated placental barrier. The permeability of BDNF through placenta barrier and fetal BBB increased with the increased dose injected. BDNF reached the fetal brain through BBB under hypoxia eschemia condition. The rates of penetration of BDNF through placental barrier and BBB increased under the condition of fetal ischemia and hypoxia. Conclusions Exogenic BDNF may partly go through placental barrier and BBB into fetal brain, which makes it possible for BDNF to be a treatment for fetus suffered from ischemia and hypoxia.

Objective To investigate the effect and possible signal pathway of brain - derived neurotrophic factor (BDNF) on apoptosis of rat embryo brain cells suffering from intrauterine hypoxic - ischemic injury. Methods The uterine arteries of the pregnant rats were clamped for 30 minutes in both experimental group and control group. BDNF(2 ?g) was injected into rats in experimental group while saline was injected into rats in control group through caudal veins. The samples were collected at 24, 48 and 72 hours re-spectively after artery clamping. Neuroapoptosis of different groups induced by ischemic damage was measured by TUNEL assay. The expression of extracellular signal - regulated kinase(ERK)and c - Jun - N - terminal kinase(JNK) were observed by immunohisloche-mistry.Results The number of apoptosis cells after hypoxic - ischemic injury increased progressively with time.The apoptosis cells number in experimental group were much lower in number than those of ischemic control group.The expression of ERK increased while the expression of JNK decreased in experimental group, comparing with that of the ischemic control group, with statistical signif-icance (P

OBJECTIVEThe mechanism of neonatal hypoxic-ischemic brain damage (HIBD) remains unclear and effective treatment approach is limited for this disorder. Many studies have shown that tissue-type plasminogen activator (tPA) plays an important role in nervous system. This study investigated the effect of tPA in HIBD in neonatal rats.

METHODSSeven-day-old Wistar rat pups were used for the Rice-Vannucci model of neonatal hypoxia-ischemia (HI). Brain samples were collected 1, 4, and 24 hrs after HI. FITC-Dextran was injected into the left ventricle of pups after HI to observe reperfusion defects of the neonatal brain. RT-PCR and tPA zymogram were used to detect the expression and activity of tPA. Double immunostaining, terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and DAPI staining were used to detect the expression of integrin GPIIb and fibrin and neuronal apoptosis.

RESULTSFITC-Dextran perfusion analysis indicated there was obvious infarct area in the neonatal brain and the expression of integrin GPIIb and fibrin increased significantly 1 hr after HI compared with the contralateral side. The infarct area decreased and the expression of integrin GPIIb and fibrin were reduced 4 hrs after HI. The expression and activity of tPA increased significantly in neonatal rats after HI, and peaked at 4 hrs after HI. The number of apoptotic neural cells increased progressively with the prolonged reperfusion time following HI.

CONCLUSIONSThe increase of tPA in the acute phase after HIBD may be helpful to clot dissolving, but it induces neuronal apoptosis and aggravates brain injury.

Animals ; Animals, Newborn ; Apoptosis ; Fibrin ; analysis ; Hypoxia-Ischemia, Brain ; metabolism ; pathology ; Immunohistochemistry ; In Situ Nick-End Labeling ; Platelet Membrane Glycoprotein IIb ; analysis ; Rats ; Rats, Wistar ; Reverse Transcriptase Polymerase Chain Reaction ; Tissue Plasminogen Activator ; analysis ; physiology

Pharmaceutical preparations, particularly as a "secret recipe" of traditional Chinese medicine in medical institutions, are the product of China's medical and health industry, and they are also an important means of competing of different medical institutions. Although pharmaceutical preparations have advantages and characteristics than institutes for drug and pharmaceutical companies, the quality standards of pharmaceutical preparations in medical institutions has not reached the desired level over the years. As we all know, the quality of pharmaceutical preparations is important to ensure the efficacy, especially under the environment of people pay more sttention on drug safety and effectiveness and contry increase emphasis on the stste of pharmaceutical preparations. In view of this, we will improve the grade, stability, and clinical efficacy of pharmaceutical preparations by the advanced equipment, testing instruments and the process dynamic quality control technology. Finally, we hope we can provide new ideas for the quality control of pharmaceutical preparations.
Drug Compounding ; standards ; Medicine, Chinese Traditional ; standards ; Quality Control

Objective To study the exact function of human gene 5 transactivated by pre-S1 protein of hepatitis B virus(PS1TP5)by investigating the gene expression of PS1TP5 in yeast cells. Methods Reverse transcription-polymerase chain reaction(RT-PCR)was performed to amplify the gene of PS1TP5 using the mRNA of HepG2 cells as template and the gene was cloned into pGEM-T vector.The gene of PS1TP5 was cut from pGEM-T-PS1TP5 vector and cloned into yeast expressive plasmid pGBKT7,then pGBKT7-PS1TP5 was transformed into yeast cell AH109.The yeast protein was isolated and analyzed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE) and Western hybridization.Results PS1TP5 gene was successfully amplified and identified by DNA sequencing.The digested fragment was cloned into pGBKT7 vector and transformed into yeast cell AH109.The results of SDS-PAGE and Western assay showed that the relative molecular weight of the expressed product was about 36 950,and PS1TP5 protein existed in yeast cells.Conclusion The findings suggest that PS1TP5 can be successfully expressed in yeast cell.

OBJECTIVETo evaluate the efficiency of a modified culture method for rat cerebral cortical astrocytes in vitro.

METHODSThe astrocytes derived from the cerebral cortex of 3-day-old Sprague-Dawley rats were first purified as described previously, then the cells were replanted at a low density. The culture flask was changed after 1 hour and substratum was replaced after 24 hours. Cells were syncretized to a monolayer, followed by cell passage. After three passages the cells were cultured in DMEM medium containing 10% fetal serum for a long period. The derivation of the cells was identified by immunofluorescent staining with anti-GFAP polyclonal antibodies.

RESULTSA variety of morphologically distinct astrocytes with many long processes and small cell bodies were obtained. Finally an astrocytic network occurred through cellular process connections. The immunofluorescent staining demonstrated the percentage of GFAP-positive cells was above 98%.

CONCLUSIONSThe modified culture method for astrocytes from rat cerebral tissue is reliable, with a high purity. The cultured astrocytes have a similar morphological development to those in vivo.

Animals ; Astrocytes ; physiology ; Cell Culture Techniques ; Cerebral Cortex ; cytology ; Female ; Glial Fibrillary Acidic Protein ; analysis ; Male ; Rats ; Rats, Sprague-Dawley

To investigate the possible involvement of Ras signaling in the hematopoietic differentiation of embryonic stem cells (ES cells), ES cells were transfected with RasN17, the dominant-negative mutant of Ras. Western blot was used to test the effect of RasN17 expression on Erk1/2 and Akt phosphorylation, semi-quantitative RT-PCR was used to detect expression of gene related to hematopoiesis in differentiation of ES cells. The results showed that the expression of RasN17 in the ES cells remarkably downregulated the phosphorylation of Erk1/2 and Akt simultaneously. Moreover, the expression of several markers related with hematopoiesis including Runx1, SCL and beta-major globin, were significantly suppressed in the EB expressing RasN17, whereas the transcription of Flk1, a gene required earlier than SCL in development of hematopoietic and endothelial lineages, was not influenced. It is concluded that the activation of Ras is pivotal for in vitro hematopoietic differentiation of ES cells.
Animals ; Cell Differentiation ; physiology ; Cells, Cultured ; Embryonic Stem Cells ; cytology ; Genes, ras ; Hematopoiesis ; physiology ; Hematopoietic Stem Cells ; cytology ; Mice ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Phosphorylation ; Signal Transduction ; ras Proteins ; physiology