Objective To study the molecular mechanism of different sensitivities to apoptosis induced by low concentration of As2O3 in PML-RARα negative HL-60 cells and PML-RARα positive NB4 cells. Meth-ods NB4 and HL-60 cells were cultured with As2O3 for 1 to 4 days; cell proliferation were detected by MTT method; the apoptosis was detected by flow cytometry,Bcl-2,Bax and Fas mRNA were determined by RT-PCR. Results The proliferation of NB4 cells was inhibited obviously by As2O3(1.0 μmol/L)with the induction of apoptosis( P <0.05) ,which was accompanied by the down-regulation of Bcl-2 mRNA expression( P <0.05)and the ratio of Bcl-2/Bax(P <0.05), but there was no obvious variation of Bax and Fas expression( P >0.05). Inhibition of proliferation and apoptosis were not obvious in PML-RARα negative HL-60 cells induced by low concentration As2O3 ( P >0.05), and there was no obvious variation of Bcl-2, Bax, Fas mRNA expres-sion or Bcl/Bax ratio( P >0.05). Conclusion The ratio of Bcl-2/Bax is contributed to the different sensitiv-ities of PML-RARα negative HL-60 cells and positive NB4 cells induced by low concentration of As2O3.

OBJECTIVE: To determine the effective rule of protraction in different directions,strains, and shifts of maxillary bone,and to supply the scientific data for treatment of the maxilla in patients with cleft lip and palate. METHODS: " Based on the establishment of 3-dimensional finite element model of maxilla with cleft lip and palate,ANSYS 10.0 software was used to simulate protraction,and then we analyzed the change of maxillary stress and shift in the same force of traction in different directions. RESULTS: With 500 g per lateral protraction and the protraction angle from 20 degree to 45 degree,the maxillary shifted upward, forward, and outward, and the shape of maxillary plate bow showed internal shrinkage. There was a close relation between the internal shrinkage and the direction of protraction. The smaller the angle between the direction of protraction and the functional occlusion plane,the larger the internal shrinkage of tooth bow. The larger the angle between the direction of protraction and the functional occlusion plane,the smaller the internal shrinkage of tooth bow. CONCLUSION With protraction,the maxilla grows upward, forward, and outward, and the maxillary palate shinks internally. There is a close relation between the direction of protraction and the range of internal shrinkage.
Biomechanical Phenomena ; Cleft Lip ; therapy ; Cleft Palate ; therapy ; Extraoral Traction Appliances ; Finite Element Analysis ; Humans ; Imaging, Three-Dimensional ; Malocclusion ; therapy ; Maxilla ; physiology ; Retrognathia ; therapy

To approach the effect of CCAAT/enhancer binding proteins (C/EBPs) on un-terminal differentiation of HL-60 cells after treatment with Arsenic Trioxide ( As_2O_3) . Methods The changes of cell morphology were observed by Wright staining, the alteration in the cell proliferation was determined by WST1 experiment and the NBT reduction assay was used to detect the differentiation condition of cells, determination and analysis cell cycle. The expressions of C/EBP? and C/EBP? mRNA in HL-60 cells exposed to ATRA and As_2O_3 were assayed by semi-quantitative RT-PCR. Results It was found that ATRA could up- regulate the mRNA expression of C/EBP? obviously, but down-regulate the mRNA expression of C/EBP?. As_2O_3 could up-regulate the mRNA expression of C/EBP? lightly, down-regulate the expression of C/EBP?. Conclusion Both of ATRA and As_2O_3 can down-regulate the mRNA expression of C/EBP?,but there is no significant difference between these two groups,ATRA and As2O3 can up- regulate the mRNA expression of C/EBP?, with significant differences (P