BACKGROUND: With the development of tissue engineering, more attention has been paid to tooth regeneration. However, the resource of best seed cells is still uncertain. Therefore, alternative sources should be attached to intensive investigation. OBJECTIVE: To review the feasibility of stem cells from umbilical cord blood as seed cells for tooth regeneration. METHODS: A PubMed search was performed for articles published between January 1998 and January 2009. Key words were "tooth regeneration, seed cells, tissue engineering, umbilical cord blood, mesenchymal stem cells". Only studies written in English were included. Simultaneously, databases of China National Knowledge Infrastructure, Wanfang, and VIP published between January 1998 and January 2009 were also retrieved, using the key words of "tooth regeneration, seed cells, tissu engineering, umbilical cord blood, mesenchymal stem cells". Only studies written in Chinese were included. Totally, 40 literatures were included. RESULTS AND CONCLUSION: Seed cells, such as odontoblasts from dental germ, stem cells from dental pulp and deciduous teeth, and ectomesenchymal cells from the firstbranchial arch showed odontogenic differentiation potential in basic research. However, these cells are not practical to harvest in clinic. Although bone marrow mesenchymal stem cells have odontogenic capacity, their differentiation abilities significantly decrease with the increasing age of the donors. Stem cells from umbilical cord blood have many clinical advantages over bone marrow mesenchymal stem cells, and exhibited typical mesenchymal stem cells characteristics. Thus, we propose the hypotheses that stem cells from umbilical cord blood could be induced into odontogenic lineage and might be used as suitable seed cells for tooth regeneration to replace the lost tooth.

AIM:To investigate the effects of microRNA ( miRNA)-126 on the proliferation , migration and in-vasion of human lung cancer cell lines , and to explore its mechanism .METHODS:The A549 cells were transfected with miRNA-126 agomir by Lipofectamine 2000.The expression of miRNA-126 was detected by real-time PCR.The cell activity was detected by MTT assay .The number of viable A549 cells was counted by the method of Trypan blue exclusion .The cell colony-forming capability was determined by cell colony formation test .The cell migration and invasion abilities were assayed by wound healing and Transwell methods , respectively.The protein levels of p-EGFR, EGFR, p-AKT, AKT, p-mTOR and mTOR were determined by Western blot .RESULTS:The expression level of miRNA-126 was significantly in-creased in the A549 cells compared with negative control ( NC) group and control group ( P<0.01 ) .The proliferation of A549 cells was decreased extremely after transfected with the miRNA-126 agomir (P<0.01), so did the result of the cell colony-formation test.The migration and invasion abilities of the lung cancer cells were also significantly inhibited .The protein levels of p-EGFR, p-AKT and p-mTOR were significantly down-regulated compared with NC group and control group ( P<0.01) .CONCLUSION:Over-expression of miRNA-126 significantly inhibits the proliferation , migration and invasion ability of human lung cancer A 549 cells by down-regulation of EGFR/AKT/mTOR pathway .

Twenty kinds of amino acids are simplified into 3 types: hydrophobic amino acids (H), hydrophilic amino acids (P) and neutral amino acids (N). Each residue is reduced to a bead which locates in the position of the C?琢 atom. The off-lattice model is adopted and the relative entropy is used as a minimization function to predict the tertiary structure of a protein. A new contact intensity function is given to consist with protein design research based on the relative entropy. Testing on several real proteins from Protein Data Bank (PDB) shows the good results obtained with the model and method. The root mean square deviations (RMSD) of the predicted structures relative to the native structures range from 0.30 to 0.70 nm. A foundation for studying protein design using the HNP model and the relative entropy was made.

Objective To explore the effect of Schisandrin B (Sch B) on nuclear transcription factor E2-related factor 2 (Nrf2)/kelch-like epichlorohydrin-associated protein (Keap-1)/ peroxisome proliferation-activated receptor γ coactivator-1α (PGC-1α) signaling pathway in lung tissue of rats with severe pneumonia. Methods A rat model of severe pneumonia was first established and then randomly divided into model group, Sch B low, medium, and high dose groups and positive control group, with 10 rats in each group, and another 10 rats was selected as a blank control group. Sch B low, medium and high dose groups were given intragastrically with 2.50, 5.0, 10.0 mg/kg Sch B for intervention, the positive control group was given 1.04 mg/kg dexamethasone for intervention, and the rest of groups were given equal volume of normal saline, for 14 consecutive days. Aorta blood was taken to detect blood gas index. Lung tissue was isolated, and pathological changes, inflammatory factors and pathway-related protein expression were detected. Results The rats in the control group had normal diet, no abnormal mental state, and clear lung tissue structure. Compared with the control group, the rats in the model group were in a worse state, with symptoms such as unresponsiveness, sluggishness, and shortness of breath, inflammatory infiltration of the lung tissue, edema of the alveolar interstitium, and thickening of the alveolar wall. The PaCO2 value, TNF-α, IL-6 and IL-1β contents, Keap-1 protein expression all increased significantly (P<0.05), the PaO2 and SaO2 levels, Nrf2 and PGC-1ɑ protein expression reduced significantly (P<0.05). Compared with the model group, the adverse symptoms of rats in the Sch B low, medium, and high dose groups alleviated gradually, and the inflammatory infiltration of lung tissue and alveolar interstitial edema reduced gradually, the PaCO2 value, TNF-ɑ, IL-6 and IL-1β contents, and Keap-1 protein expression all decreased sequentially (P<0.05), the PaO2 and SaO2 values, Nrf2 and PGC-1ɑ protein expression levels increased sequentially (P<0.05). The indicators were no significant difference between the Sch B high-dose group and the positive control group (P>0.05). Conclusions Sch B can alleviate the adverse symptoms of severe pneumonia caused by Klebsiella in rats, which may be related to the activation of the NRF2/PGC-1α signaling pathway and the reduction of Keap1 protein expression.

Adolescent ; Biopsy ; Female ; Hepatocytes ; diagnostic imaging ; pathology ; Humans ; Jaundice, Chronic Idiopathic ; pathology ; Sibling Relations ; Ultrasonography

ObjectiveTo study HIV-1 DNA levels in different parts of HIV patients during the early stage of antiretroviral therapy.MethodsThe peripheral blood,gut associated lymphoid tissues and lymph nodes samples were collected before and 12 weeks after treatment in regular follow-up HIV-1/AIDS patients in Beijing Youan Hospital ( n =11 ).The average age was 39 years old ( 25 to 55 ).Mononuclear Cells were isolated by density gradient centrifugation and then used DNA extraction kit to extract DNA.Realtime quantitative polymerase chain reaction was used to examine HIV-1 DNA copy-number.Non-parametric test was used to analyse the differences of HIV-1 DNA copy numbers among groups.Results Before treatment,HIV-1 DNA copy-number in both gut associated lymphoid tissues ( 10 714 ± 2043 ) copies/106 cells and lymph nodes (9145 ± 1202) copies/106 cells were higher than that in the peripheral blood (66 ± 8) copies/106 cells ( U =0.00,P ＜0.05 ),There was no significant difference between lymph nodes and gut associated lymphoid tissues (U =46.00,P ＞0.05).After 12 weeks of treatment,HIV-1 DNA copy-number in both gut associated lymphoid tissues (1701 ± 790) copies/106 cells and lymph node (11 591 ± 1781 ) copies/106 cells were higher than the peripheral blood ( 18 ± 3 ) copies/106 cells ( Z =- 2.934,P ＜ 0.05 ).There was a significant reduction of DNA copy-number in gut associated lymphoid tissues and peripheral blood after treatment (Z =- 2.934,P ＜ 0.05 ).Conclusion Gut associated lymphoid tissues and lymph nodes may be important latent reservoirs for HIV-1 DNA.

Objective To investigate the percentage of CD5-positive B cells in peripheral blood mononuclear cells(PBMC) of patients with chronic HCV infection and its clinical significance.Methods The expression of CD5 molecule on B cell surface was detected by flow cytometry and HCV RNA copies were detected by real-time PCR.Results The percentage of CD5+-B cells significantly increased in the patients with chronic HCV infection(58.4%?9.8%) compared with healthy controls(22.5%?5.9%)(P

Objective To investigate the effects of human interlukin-13 (hIL-13) on the expression of E- selectin and intercellular adhesion molecule-1(ICAM-1) on bovine aortic endothelial cells(BAECs) stimulated by tumor necrosis factor alpha(TNF-?), and to provide experimental basis for hIL-13 inducing immunity endure and relieving the repulsion reaction of xenograft. Methods BAECs were co-cultured with different concentrations of hIL-13 for 2 h and followed by co-cultured with 4 ng/ml TNF-? for 6 h or 18 h. The expressions of E-selectin and ICAM-1 on BAECs were detected by Cell-ELISA. The effect of hIL-13 on activity of BAECs was detected by MTT colorimetry.Results BAECs pretreateded with hIL-13 could inhibit the expression of E-selectin and ICAM-1 induced by TNF-?, and showed a does-dependent manner from 5 ng/ml to 20 ng/ml of hIL-13 (P

Objective:To investigate the effect of RNA-mediated interference EGFR (epidermal growth factor receptor) expression on the apoptosis of muitidrug-resisitant ovarian cancer cell line SKOV3/DDP. Methods: Small hairpin RNA (shRNA) targeting EGFR was synthesized and recombinant plasmid containing pEGFR-shRNA was constructed, pEGFR-shRNA was tansfected into SKOV3/DDP cells by liposome system, untransfected cells and SKOV3/DDP cells tansfected with nonspecific-shRNA (Ctrl-shRNA) were used as control. Expression of EGFR mRNA and protein in SKOV3/DDP cells was examined by RT-PCR and immunocytochemistry after transfection, respectively. The apopototic rates and cell cy-cles of SKOV3/DDP cells were detected by flow cytometry. Results: Compared with Ctrl-shRNA-transfected cells, the ex-pression of EGFR mRNA and protein in pEGFR-shRNA-transfected SKOV3/DDP cells was significantly inhibited. Flow cytometry results showed that cell cycle distribution in pEGFR-shRNA-transfected SKOV3/DDP cells was dramatically changed, and the apoptosis rate was significantly increased after further treatment with cisplatin for 24 h. Conclusion: EGFR-targeted interference RNA can inhibit the expression of EGFR in SKOV3/DDP cells, thereby regulating the cell cy-cle and increasing apoptosis of multidrug-resistant SKOV3/DDP cells.

Objective:To research whether ectopic over-expression of Pim-2 could cause chang-liver cell (LO2) malignant transformation,to explore the relationship between Pim-2 protein and hepatocellular carcinoma.Methods:Three groups of cells were arranged including human chang liver cell line LO2 (group C),LO2 cells transfected with empty-vector (group B) and LO2 cells transfected with Pim-2 gene (group A).Pim-2 expression levels were detected.The morphology,proliferation level,apoptosis rate and migration ability of the cells were detected respectively.The cells were subcutaneously inoculated into athymic mice and the microstructures of the neoplasm were observed by optical and electron microscopy.Results:Compared with group B,Pim-2 expression levels were significantly higher in group A (P＜0.05),and their morphology had obvious malignant changes.They also showed a significantly increased proliferation rate (P＜0.05) and migration capacity (P＜0.05),as well as a significantly decreased apoptosis rate (P＜0.05).Only the athymic mice inoculated with group A could generate neoplasm,and the morphology of the neoplasm coincided with that of the hepatoma.Conclusion:Both the morphological and biological changes of LO2/Pim-2 cells indicate the trend of malignant transformation,which could generate hepatoma in athymic mice.Pim-2 could induce malignant transformation of human liver.