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Objective:To assess the impacts of feeding type and non-nutritive sucking activity on occlusion in deciduous dentition in WeiFang city.Methods:The occlusion of 958 children aged 3 -5 years old in WeiFang city and their feeding types as well as the non-nutritive sucking habit during the first 1 2 months after birth were investigated by questionaire study.Data were statistically ana-lysed.Results:The prevalence of malocclusion in non-nutritive sucking habit group and non-habit group was 42% and 22% respec-tively(P =0.000 2).The type of feeding did not have effect on occlusion and openbite.The prevalence of openbite in the children with sucking habit and in those without habit was 17% and 4% respectively(P <0.000 1 ).The prevalence of posterior crossbite in the chil-dren with bottlefeeding and those with breastfeeding was 1 1 % and 4% respectively(P =0.000 2).The prevalence of posterior crossbite in the children with sucking habit and those without habit was 9% and 4% respectively(P =0.036 7).Conclusion:Non-nutritive sucking habit rather than feeding type in the first 1 2 months after birth is the main risk factor of malocclusion,breastfeeding is the pro-tective factor to occlusion.
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OBJECTIVE: To study the effect of transplanting autologous bone marrow mesenchymal stem cells (BMSCs) at different time point after myocardial infarction on cardiac function, and to approach its mechanism. METHODS: Thirty healthy Taihu Meishan swine were prepared for myocardial infarction models, and divided into 6 experimental groups, with 5 animals in each group. BMSCs were transplanted into 3 groups through coronary artery at 3 hours, 2 weeks and 4 weeks after myocardial infarction, named G1, G2 and G4, respectively. Meantime, DMEM culture medium was injected in the control group at correspond periods. Each swine was examined by MRI and Doppler before infarction, before transplantation, and at 8 weeks after infarction, respectively, to observe the change of cardiac function. The VEGF values of blood serum in different periods after transplantation were detected. All swine hearts were harvested after 8 weeks (the experimental terminus), and the planting and differentiation of transplanted cells in cardiac muscle were detected by the method of immunity histochemistry. The density of blood vessels in cardiac muscle was acquired simultaneously. RESULTS: There was no statistic difference of cardiac function between G1 and its control groups. The groups of G2 and G4 could improve cardiac function compared to the control groups, and G4 was superior to G2 (P < 0.05). There was no statistics difference of the decreased absolute value of myocardial infarcted area between G1 and the control groups. The myocardial infarcted area of G4 was greater than G2 (P < 0.05). The value of blood serum VEGF rose obviously in the G2 and G4, while G1 and all control groups did not present any marked changes, the rising amplitude of G4 was larger than G2 (P < 0.05). There were not any planting and differentiation of transplanted stem cells in G1 and all control groups at 8 weeks after infarction, but G2 and G4 could display, especially in G4 group (P < 0.05). There was no statistic difference of the density of blood vessels in cardiac muscle between G1 and all control groups at 8 weeks after infarction, but the differences were significant in all experimental groups, which was superior in G4 group to G1 and G2 groups (P < 0.05).CONCLUSION: There is disparity of transplanting BMSCs at different time point after myocardial infarction on cardiac function. Transplantation in acute period of myocardial infarction has no significant effect, but transplantation in non-acute period can ameliorate cardiac function. The therapeutic effect of transplanted at 4 weeks is superior to other time point. The MRI can display the location and compass of infarct cardiac muscle, and reflect the variation of cardiac function.
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BACKGROUND: A great quantity of cell loss in early stage following stem cell transplantation can significantly affect transplantation effect. Presently, it is confirmed that overexpression of AKT1 gene significantly inhibit cell apoptosis. OBJECTIVE: To explore whether AKT1 gene overexpression can block stem cell apoptosis under hypoxic condition following pig autologous bone marrow mesenchymal stem cell (BMSC) transplantation, and the effect of repairing damaged myocardium. DESIGN, TIME AND SETTING: The randomized controlled animal study was performed at the Soochow University from August 2005 to February 2007.MATERIALS: A total of 24 healthy male Meishan pigs were supplied by the Animal Experimental Center of Soochow University. METHODS: The CDS (regulation domin of AKT1) AKT1-cDNA fragment was amplified. Lentivector Packaging Kit was used to transfect BMSCs after synthesized with pCDH1-AKT1 shuttling plasmid. Following BrdU labeling, models of myocardial infarction were constructed by occluding the distal left anterior descending coronary artery in pigs with gelatin sponge. 4 weeks later, pigs were randomly divided into four groups: the model control group, the DMEM group, the BMSCs group, and the AKT-transfected group. In model control group, there was no other injection after occluding the left anterior descending coronary artery. In the DMEM group, 5 mL DMEM was injected into the coronary artery. 5 mL BMSCs (1×10~7 cells) were infused into the coronary artery in the BMSCs group. 5 mL BMSCs transfected with the AKT1 gene were injected in the AKT-transfected group MAIN OUTCOME MEASURES: Western blot analysis and real time RT-PCR were used to test the plasmid. The cardiac function was evaluated by magnetic resonance image. Histological characteristics of the myocardium were observed using immunohistochemistry. Serum vascular endothelial growth factor and transforming growth factor β1 levels were determined by ELISA. RESULTS: AKT1-cDNA was cloned into pCDH1-MCS1-EF1-copGFP and the sequence was confirmed in comparison with the published one. AKT mRNA expression could be detected distinctly 24 and 48 hours after transfecting cells. The expression of AKT1 intensity in MSCs remained strong 2 weeks later with detected by real time RT-PCR and Western blot analysis. AKT1-mRNA transcriptional levels were 120 times of primary cells. Before the cell implantation, the left ventricular end-diastolic dimension increased and the stroke volume decreased in the myocardial infarction hearts. The cardiac function was significantly improved after cell implantation, and the implanted MSCs prevented the infarct region from thinning and expanding, improved contraction and increased perfusion in all groups relative to the control hearts. The left ventricular chamber size was smaller in the hearts with being transplanted cells than that in the control hearts. Moreover, the improvement was even markedly greater in AKT-transfected group (P < 0.05). Hematoxylin-eosin staining results showed that fibering was significant in the model control group and DMEM group. Island-like myocardium was observed in the infarct zone of the BMSCs group and AKT-transfected group, and plenty of small vessels-shape structure was detected in the AKT-transfected group. Immunohistochemistry demonstrated that Von Willebrand Factor (vWF) and Cx-43 expression was determined in the myocardium in the BMSCs group and AKT-transfected group, and the proportion of BrdU and Cx-43-positive cells to BrdU-positive cells was significantly greater in the AKT-transfected group compared with the BMSCs group 4 weeks following transplantation (P < 0.05). Following cell transplantation, vascular endothelial growth factor levels were gradually increased, peaked at 1 week, gradually decreased, and reached a normal level at 4 weeks. Transforming growth factor p1 levels were gradually reduced, and significantly less than the model control group, DMEM group 4 weeks later (P < 0.05), and significantly lower than that pretransplantation (P < 0.05).CONCLUSION: Using lentiviral vector to construct with AKT1 gene could stably make BMSCs overexpress AKT1. The BMSCs engraftment in host myocardium might improve the left ventricle function by attenuating the contractile dysfunction and pathologic thinning in this model of left ventricular wall infarction. AKT1 overexpression can significantly improve cardiac function following infarction.