ABSTRACT
BACKGROUND:During the percutaneous vertebroplasty, the optimal dose of bone cement that can bring favorable cement dispersion and remodel the biomechanical balance of the fractured vertebrae remains controversial. OBJECTIVE:To investigate the dispersion degree of small dose of bone cement in vertebroplasty. METHODS: In this experiment, 18 sheep selected with the same condition were randomly divided into three groups (group A, group B, group C), 6 in each group. A model of thoracolumbar vertebral compression fracture (T12, L1, L2) was made in each sheep. The injected volume of bone cement in groups A, B, C was 15％, 20％, 25％ of the average volume of adjacent vertebral bodies, respectively. Postoperative CT images were used to evaluate the bone cement dispersion. Dispersion degree of bone cement among the three groups was compared by the Kruskal-Wallis test. RESULTS AND CONCLUSION:There was no statistical difference in the dispersion degree of bone cement among the three groups, and the excellent and good rate of dispersion was over 80％. To conclude, the optimal dose of bone cement injected into the fractured vertebra is 15％ of the average volume of adjacent vertebral bodies, which can achieve good dispersion degree and restore the biomechanical stability of the vertebral body.
ABSTRACT
<p><b>OBJECTIVE</b>To explore the relationship between the methylation status of CpG islands in the promoter region of 10 genes in breast cancer cells and their sensitivity to 5-fluouracil (5-Fu), and to identify the genes responsible for the 5-Fu resistance in breast cancer.</p><p><b>METHODS</b>Three cell lines (differently resistant to chemotherapy) were used in this study: Bcap-37 (IC(50): 289.77 microg/ml), T47D (IC(50): 134.16 microg/ml) and ZR-75-30 (IC(50): 4.20 microg/ml). The methylation profile of 10 genes (BAG1, C11ORF31, CBR1, CBR4, GJA1, FOXL2, IGFBP6, P4HA1, SRI and TYMS) in the 3 breast cancer cell lines was determined by methylation specific PCR. The steady-state mRNAs of ABCC8, CHFR and IGFBP6 genes were quantified by real-time RT PCR analysis.</p><p><b>RESULTS</b>Among the 10 genes, only genes IGFBP6 and FOXL2 displayed differential DNA methylation pattern between the 5-Fu-resistant and 5-Fu-sensitive cell lines. The mRNA expression level of genes PRSS21, LOX, IGFBP6, ABCC8 and CHFR was quantified by real-time RT-PCR analysis. Except for CHFR, the expression level of the other 4 genes was correlated with the methylation status of CpG islands, namely, a lower expression level with methylation status and a higher level with demethylation status.</p><p><b>CONCLUSION</b>The results of the present study have demonstrated that there are 8 genes with differential methylation status in chemosensitive and chemoresistant breast cancer cell lines, i.e. two genes more than the six genes we reported previously. Our findings provide both mechanistic insights for the drug resistance of breast cancer and the basis for further studies on potential application of the DNA methylation in this set of genes for prediction of chemosensitivity of breast cancer.</p>