BACKGROUND AND OBJECTIVESince the proposal of the tumor stem cell hypothesis, considerable interest has been devoted to the isolation and purification of tumor stem cells. Tumor stem cell enrichment from primary tumor derived cell spheres has been demonstrated in specific, serum-free media. This goal of this study is to establish a method of cultivating floating tumor spheres from neuroblastoma cells and to confirm that neuroblastoma spheres are rich in tumor stem cells.

METHODSBone marrow aspirates were obtained from pediatric patients diagnosed with stage IV neuroblastoma. Primary tumor cells were isolated and cultivated in serum-free, stem cell-selective medium. Single sphere-forming cells were cultivated under serum-free conditions; their cloning efficiency and monoclonal tumor sphere formation rates were calculated. The expression of stem cell marker genes Oct-4 and Bmi-1 was detected by RT-PCR in sphere-forming cells and parental neurolastoma cells. Sphere-forming cells were injected into the armpit of nude mice with subsequent assessment for tumor growth. Sphere-forming cells were cultivated in differentiation medium containing 5 μmol/L 13-cis retinoic acid; changes in cell morphology were observed.

RESULTSNeuroblastoma cells formed non-adherent neurospheres under serum-free, stem cell-selective conditions after a period of 4 to 6 days. A single cell dissociated from a neurosphere could reform a monoclonal sphere; cloning efficiency and monoclonal sphere formation rates were 55.3% and 26.3%, respectively. RT-PCR results revealed heightened tumor sphere expression of Oct-4 and Bmi-1 as compared with parental tumor cells. Fourteen days after injection of 10(4) sphere-forming cells into nude mice, a neuroblastoma xenograft formed. Treatment of sphere-forming cells with 13-cis retinoic acid induced a gradual differentiation to neuronal cell morphology.

CONCLUSIONSNeuroblastoma derived tumor spheres enrich tumor stem cells and the cultivation of primary neuroblastoma cells in serum-free, stem cell-selective medium is an effective method to dissociate and purify tumor stem cells in vitro.

Animals ; Cell Culture Techniques ; methods ; Cell Differentiation ; drug effects ; Child ; Culture Media, Serum-Free ; Humans ; Isotretinoin ; pharmacology ; Mice ; Mice, Nude ; Neoplasm Transplantation ; Neoplastic Stem Cells ; metabolism ; pathology ; Neuroblastoma ; metabolism ; pathology ; Nuclear Proteins ; metabolism ; Octamer Transcription Factor-3 ; metabolism ; Polycomb Repressive Complex 1 ; Proto-Oncogene Proteins ; metabolism ; Repressor Proteins ; metabolism ; Spheroids, Cellular ; pathology ; Xenograft Model Antitumor Assays

Objective:To investigate the causal correlation between depression and stress urinary incontinence(SUI)using Mendelian randomization(MR)analysis.Methods:We searched the FinnGen Consortium database for genome-wide association studies(GWAS)on depression and obtained 23 424 case samples and 192 220 control samples,with the GWAS data on SUI provided by the UK Biobank,including 4 340 case samples and 458 670 control samples.We investigated the correlation between depression and SUI based on the depression data collected from the Psychiatric Genomics Consortium(PGC).We employed inverse-variance weighting as the main method for the MR study,and performed sensitivity analysis to verify the accuracy and stability of the findings.Results:Analysis of the data from the UK Biobank and FinnGen Consortium showed that depression was significantly correlated with an increased risk of SUI(P=0.005),but not SUI with the risk of depression(P=0.927).And analysis of the PGC data verified the correlation of depression with the increased risk of SUI(P=0.043).Conclusion:Depression is associated with an increased risk of SUI,while SUI does not increase the risk of depression.

Comprehensive Laboratory of Biochemistry and Molecular Biology is a compulsory open online course that integrates lab skill training and innovation ability training for undergraduates majoring in biology in Beijing Normal University. This course focuses on alkaline phosphatase, including cloning of the Escherichia coli alkaline phosphatase gene, expression and purification of the protein, research on its enzymatic characteristics, preparation of its antibody and determination the titers of the antibody, etc. The comprehensive lab course covers from the gene to the protein, so that students can learn and master commonly used biochemical and molecular biology experimental techniques systematically. Escherichia coli alkaline phosphatase is an ideal experimental research object. And there are very classic and systematic scientific research literature reports. As important auxiliary teaching means, these literature resources can help teachers and students to carry out learning inquiries, form rational and critical scientific attitudes and spirits, and also greatly improve the quality of teaching and students' scientific research quality, which plays an important role in the construction of first-class course of Comprehensive Laboratory of Biochemistry and Molecular Biology.

Objective To campare biomechanical effects of different postural compression techniques on three-dimensional model of lumbar disc herniation(LDH)by finite element analysis.Methods Lumbar CT image of a 48-year-old female patient with LDH(heighted 163 cm,weighted 53 kg)was collected.Mimics 20.0,Geomagic Studio,Solidwords and other software were used to establish three-dimensional finite element model of LDH on L4,5 segments.Compression techniques under horizon-tal position,30° forward bending and 10° backward extension were simulated respectively.After applying the pressure,the ef-fects of compression techniques under different positions on stress,strain and displacement of various tissues of intervertebral disc and nerve root were observed.Results L4,5 segment finite element model was successfully established,and the model was validated.When compression manipulation was performed on the horizontal position,30° flexion and 10° extension,the annular stress were 0.732,5.929,1.286 MPa,the nucleus pulposus stress were 0.190,1.527,0.295 MPa,and the annular strain were 0.097,0.922 and 0.424,the strain sizes of nucleus pulposus were 0.153,1.222 and 0.282,respectively.The overall displace-ment distance of intervertebral disc on Y direction were-3.707,-18.990,-4.171 mm,and displacement distance of nerve root on Y direction were+7.836,+5.341,+3.859 mm,respectively.The relative displacement distances of nerve root and interverte-bral disc on Y direction were 11.543,24.331 and 8.030 mm,respectively.Conclusion Compression manipulation could make herniated intervertebral disc produce contraction and retraction trend,by increasing the distance between herniated interverte-bral disc and nerve root,to reduce symptoms of nerve compression,to achieve purpose of treatment for patients with LDH,in which the compression manipulation is more effective when the forward flexion is 30°.