Nervous system develops from multipotential stem cells of the embryonic neural tube.The discovery of cells of stem-like properties in the adult central nervous system(CNS)has provoked an intense search for ways to utilize their potential for treatments of multiple neurological disorders.Expansion and recruitment of endogenous progenitors may be limited in treating widespread cell loss in the adult CNS.Transplantation of neural stem cells(NSCs)or more restricted progenitors to replace cells lost to injury or disease may facilitate functional recovery in a spectrum of neurological disorders.A major challenge to the development of effective NSCs therapies is to direct the fate of the newly generated cells to specifically replace those lost to disease.The key to the effective treatment of NSCs is molecular regulation of the differentiation of NSCs and their progeny in areas of injury to the adult CNS,the fate of transplanted stem cells is also important.

BACKGROUND:Finding of neural stem cells(NSCs)brings new hope for repairing central nervous system(CNS)injury.However,the influence of internal environment after brain injury on the survival and differentiation of NSCs is a complexand variable process.OBJECTIVE:To observe the survival and differentiation of human embryonic NSCs following implantation into rats with fluid percussion brain injury.DESIGN:Open experiment.SETTING:Department of Neurosurgery,Guangdong Provincial Hospital of Traditional Chinese Medicine;Beijing Institute of Neurosurgery.MATERIALS:This experiment was carried out In the Laboratory of Neural Stem Cells,Beijing Institute of Neurosurgery from September 2002 to March 2003.Twenty-four female SD rats,aged 7 weeks,with body mass of(250±10)g,were provided by the Experimental Animal lnstitute, Chinese Academy of Medical Sciences[License Nd. SCXK(Jing)2002-2003]. Cerebrum of 8-week aborted fetus was obtained (Informed consents were obtained from parturients and their relatives). Fetal survival was monitored by B ultrasonic wave during abortion. BrdU monoclonal antibody(Sigma Company),rabbit anti-nidogen polyclonal antibody(Chemicon Company),mouse anti-microtubule-associated protein 2 (MAP-2)monoclonal antibody(Neomarkers Company),rabbit anti-gliaI fibrillary acidic protein(GFAP)polyclonal antibody (Biogenex Company).METHODS:① CerebraI cortex cells of 8-week aborted human fetus was harvested and cultured in vitro for obtaining human embryronic NSCs.②Rat models of hydraulic impact injury were developed.Bone window of motor sensory area of cerebral cortex was set at 2.5mm posterior to bregma which was zero point and 3.0 mm lateral to midline.Hydraulic impact injury parameters were set as impact pressure 0.3 MPa. impact time 25 ms and impact time once. ③BrdU-labeled human embryronic NSCs were implanted into injured area al 24 hours after injury.After 1 and 4 weeks.rats were sacrificed.Adjacent sections were doubly stained bv BrdU/MAP-2 and BrdU/GFAP.MAIN OUTCOME MEASURES:①Survival and immigration of implanted human embryonic NSCs.②Differentiation of implanted human embryonic NSCs.RESULTS:①BrdU-positive cells were oval and brown.At 1 and 4 weeks after implantation,BrdU-positive cells survived and migrated,and they migrated more widely at 4 weeks after implantation. ②At 1 week after implantation,more BrdU-positive cells were found in the subcortical granular layer and subcortex,and BrdU/MAP-2-positive cells were more than BrdU/GFAP-positive cells;At 4 weeks after implantation,BrdU-positive cells were significantly reduced,and found in choroid plexus and blood capillary,and BrdU/GFAP-positive cells were more than BrdU/MAP-2-positive cells.CONCLUSION:Implanted human embryonic NSCs can survive in the region of brain injury.gradually differentiate into astrocytes during rehabilitation and are easily digested by endothelial phagocytes.It indicates that immunological rejaction possibly influences the survival of human embryonic NSCs.

Objective To explore the application and efficacy of laparoscopic radical operation for rectal cancer after preoperative short-time radiotherapy.Methods The clinical data of 108 patients with Dukes B and C rectal cancer were analyzed retrospectively.Thirty-five patients underwent laparoscopic radical operation after preoperative short-time radiotherapy,meanwhile 30 patients underwent laparoscopic radical operation,and 43 patients underwent open operation,both later groups without preoperative radiotherapy.Results There were not significant differences in preoperative general condition,tumor size and stage,pathological type,site of operation,and mode of operation between the 3 groups.But there was a higher rate of radical resection and sphincter preservation in the laparoscopic operation plus radiotherapy group than in the other groups(P

Objective To investigate the remyelination after Schwann cells grafted into injured middle brain in rat.Methods Schwann cells originated from sciatic nerves of 1 to 2 day old rat were expanded and labeled by BrdU in vitro, transplanted into the rat middle brain injured by electric needle stimulus. Immunohistochemistry and myelin staining were used to locate in the BrdU positive cells and investigate remyelination.Results BrdU positive cells could be identified till at least 8 months after grafting, which mainly migrated toward injured ipsilateral cortex. New myelination could be seen in destructed brain stem area. Conclusion Schwann cells transplantation could promote CNS regeneration.

ObjectiveTo explore the method of co-culture of Schwann cell(SCs) with fascia and provide experimental basis for repairing transected nerve.MethodsSCs were co-cultured with fascia.Double staining by anti-BrdU and anti-S-100,S-100 fluorescent staining and anti-BrdU staining were used.ResultsThere were a plenty of SCs around fascia proliferated rapidly and disposed in parallel. SCs could be distinguished from fibroblastic cells by S-100 fluorescent staining and also be staining positive by anti-BrdU antibody,implying their high proliferous ability. Anti-BrdU and anti-S-100 staining showed numerous double staining positive SCs on the fascia: nucleus was stained deep blue while cytoplasm was stained red.ConclusionMany SCs with high proliferous ability were seen on the fascia, which can be used to repair transected nerve.

Objective To describe the high-resolution CT(HRCT)findings of arc-welders with early pneumoconiosis and to evaluate manifestation in different course of disease.Methods Seventy-six arc-welders with a one to thirty-eight(mean,14)years history of exposure underwent CT and HRCT scanning.The extent of abnormalities were detected.The relations of age and year history of exposure were analysed in different groups.Results Thirty-eight welders(38/76,50%)showed positive characteristic findings with conventional CT.Predominant thin-section CT findings were poorly-defined centrilobular micronodules(18/76,23.7%),branching linear structure(20/76,26.3%).The mean age in group of branching linear structure[(39±9)years old]was elder than of poorly-defined centrilobular micronodules[(34±7)years old].There was no statistical difference between the two groups(t=-1.648,P＞0.05).The mean length of service at exposure in group of branching linear structure[(15±8)years]was longer than of poorlydefined centrilobular micronodules[(10±5)years].And the significant differences were showed between the two groups in the year history of exposure(t=-2.108,P＜0.05).Conclusions Poorly defined centrilobular micronodules and branching linear structures were the thin-section CT findings most frequently seen in patients with arc-welders'pneumoconiosis and the former may be one early stage characteristic finding of arc-welders'pneumoconiosis.HRCT is useful in achieving more accurate categorization of the parenchymal changes in arc-welders'pneumoconiosis.

ObjectiveTo observe the effect on repairing facial nerve injury of rabbits by neural stem cells and autologous fasia. Methods22 rabbits with transected facial nerve were divided into 2 groups randomly, control group (8 rabbits,15 sides totally), which transected facial nerve were wrapped by autologous fasia, and treament group (14 rabbits, 20 sides totally), which were wrapped by neural stem cells and autologous fasia. Six weeks after transplantation, neuro-electrophysiological test, immunohistochemical examination were done. The number and thickness of myelin in the re-connected area of transected facial nerve were observed. ResultsThe transplanted animals recovered much better than that in control group (P<0.05). Immunohistochemical examination showed a great deal of BrdU positive cells around the re-connected area of transected facial nerve. Immunohistochemical staining also found plenty of regenerative myelins in this area in the treatment group. While in control group, there were no BrdU positive cells and only a few of regenerative myelins in the same area. ConclusionTransplantation of neural stem cells combined with autologous fasia might become the new method to treat facial nerve injury.

ObjectiveTo investigate the effects of fluid percussion injury(FPI) on survival and differentiation of transplanted human embryonic neural stem cells (HNSCs) in rats. MethodsThe HNSCs were separated from the cerebral cortex of the 8-week-old fetal and were cultured in DMEM/F12 combinated with EGF, bFGF and LIF. The rat models of FPI were made with fluid percussion system. The HNSCs labeled with BrdU were transplanted into the injured zone 24 hours after brain injury, then the rats were killed at the 1st and 4th week post-transplanted stages, and the brain slices were stained with immunocytochemistry. The GFAP, MAP-2, and BrdU positive cells were investigated.ResultsThe transplanted HNSCs migrated to the whole brain, and differentiated into GFAP and MAP-2 positive cells. MAP-2 positive cells were observed at 1 week post-transplanted stage, on the contrary, more GFAP positive cells were discovered 4 weeks after transplantation. Part of the HNSCs migrated to the choroids plexus of the lateral ventricle and microvessels. ConclusionThe transplanted HNSCs survive in the injured zone, and differentiate into astrocytes gradually during the recovery. The host devours part of the HNSCs.