考试应激对大学生心理状态和咬合功能的影响

目的:评估考试作为一过性应激事件对在校大学生心理健康和咬合功能的影响.方法:47名学生志愿者[17男,30女;(19.30±1.53)岁],无咬合异常.于期末考试前一周和假期后一周分别用SCL-90量表评估心理状态,检测紧咬与咀嚼不同类型食物块时颞肌和咬肌的肌电活动.结果:受试者躯体化、人际关系、抑郁、焦虑和偏执5个因子改变明显(P＜0.05).配对t检验分析咀嚼肌功能表明,咬肌重叠指数在咀嚼胡萝卜和活动指数在咀嚼山楂糕时差异有统计学意义(P=0.014,0.018),其他咀嚼状态指标未见显著改变.结论:考试应激显著影响大学生心理水平,咬合功能无明显改变.     

Transwell共培养条件下诱导脂肪干细胞成骨能力的改变

BACKGROUND:Under co-culture conditions, mesenchymal stem cells could regulate osteogenic differentiation and osteogenesis of osteoblasts. OBJECTIVE:To observe the osteogenic efficiency of osteoblastic precursor cells co-cultured with undifferentiated bone marrow-derived mesenchymal stem cells, umbilical cord-derived mesenchymal stem cells, or placenta-derived mesenchymal stem cells in mineralization medium. METHODS:Adipose-derived stem cells were induced in osteogenic differentiation medium for 7 days before being indirectly co-cultured with undifferentiated mesenchymal stem cells isolated from different tissues (bone marrow group, umbilical cord group and placenta group) in Transwell plates. Induced adipose-derived stem cells cultured alone served as control group. At different experimental intervals, quantitative analysis of alkaline phosphatase activity and calcified matrix was preformed to observe the effects of mesenchymal stem cells from different sources on the osteogenic efficiency of induced adipose-derived stem cells. RESULTS AND CONCLUSION:Expression of alkaline phosphatase was significantly higher in different experimental groups than the control group (P < 0.05), and it was also higher in the bone marrow group than the umbilical cord and placenta groups (P < 0.05). Quantitative analysis of calcified matrix revealed that the experimental groups were significantly higher than the control group (P < 0.05); and in experimental groups, the umbilical cord group was higher than bone marrow group and placenta group(P < 0.05). These findings indicate that the osteogenic efficiency of induced adipose-derived stem cells is improved dramatically under co-culture conditions.