Objective To explore the relevance between lymphatic metastasis and CT findings in colorectal cancer,and to estab-lish the logistic regression model to realize CT prediction for N staging in colorectal cancer.Methods Take 53 patients with complete data and colorectal cancer confirmed by pathology,and conduct correlation and regression analysis on pathological results based on the size,shape,density,edge and distribution characteristics of the regional lymph nodes that were expressed on CT images.Results It was predicted that patients with colorectal cancer showed lymph node metastasis,a number of lymph nodes with the minor axis≥ 8 mm and the irregular margin were selected in Logistic stepwise regression,the sensitivity of probabilistic model was predicted to be 85.7 %,specificity was 91.7 % and accuracy was 88.9 %;predict whether it had N2 stage,a number of lymph nodes with the heterogeneous density and the fuzzy margin were selected in Logistic stepwise regression,the sensitivity of probabilistic model was predicted to be 60.0 %,specificity 94.3 % and accuracy 86.7 %.Conclusion Lymph nodes with minor axis ≥ 8 mm,irregular margin,and heterogeneous density were the most important indicators for N staging in colorectal cancer,the combination and weigh-ting of these indicators can improve the accuracy of N staging in colorectal cancer.

Objective To investigate the correlation between drug-resistant genes and mobile genetic elements in multi-drug resistant Escherichia coli,and to explore phylogeny among the strains.MethodsTotally 20 strains of multi-drug resistant Escherichia coli were collected from Pan' an Hospital,Zhejiang Province during June 2009 and June 2010.Beta-lactam-resistance genes,aminoglycoside-resistance genes,genetic markers of mobile genetic elements were analyzed by PCR.Index and sample cluster analysis were performed on above results. Results In 20 strains of Escherichia coli,4 kinds of beta-lactamresistance genes,4 kinds of aminoglycoside-resistance genes,and 5 kinds of genetic markers of mobile genetic elements were detected.Index cluster analysis showed that correlation existed between resistance genes TEM,CTX-M-1,aadA5 and mobile genetic elements traA,IS26,ISEcpl; and correlation also existed between resistance genes OXA-1,aac(6′)-Ⅰ b,ant(3)-Ⅰ,rmtB and mobile genetic elements trbC,IS903.Sample cluster analysis showed that this group of Escherichia coli could be divided into 2 groups which were genetically different.ConclusionsDrug-resistant genes in multi-drug resistant Escherichia coli are correlated with mobile genetic elements.Sample cluster analysis can reveal phylogeny among the strains,which is important for hospital infection control.

Objective:To discuss the effect of downregulating microRNA-208a(miR-208a)on the resistance of the colorectal cancer cells to 5-fluorouracil(5-FU),and to clarify its related molecular mechanism.Methods:Real-time fluorescence quantitative PCR(RT-qPCR)method was used to detect the expression levels of miR-208a and secreted frizzled-related protein 1(SFRP1)mRNA in the 5-FU-resistant colorectal cancer cell line HT-29/5-FU and its parent HT-29 cells.The HT-29/5-FU cells were transfected with miR-208a inhibitor plasmid and its negative control plasmid(inhibitor-NC),and SFRP1 small interfering RNA(si-SFRP1)and its negative control plasmid(si-NC),either separately or in combination,followed by treatment with 5-FU.The cells were divided into inhibitor-NC group,miR-208a inhibitor group,miR-208a inhibitor+si-NC group,and miR-208a inhibitor+si-SFRP1 group.MTT assay was used to detect the proliferation activities of the cells and the resistance indexes were calculated;Annexin V-FITC/PI double staining and flow cytometry were used to detect the apoptotic rates of the cells after treated with different concentrations of 5-FU;Western blotting method was used to detect the expression levels of SFRP1,β-catenin,P-glycoprotein(P-gp),and ATP-binding cassette subfamily B member 1(ABCB1)proteins in the cells in various groups;dual-luciferase reporter gene assay was used to validate the targeting relationship between miR-208a and SFRP1.Results:Compared with HT-29 cells,the expression level of miR-208a in the HT-29/5-FU cells was increased(P＜0.05),and the expression level of SFRP1 mRNA was decreased(P＜0.05).Compared with inhibitor-NC group,the proliferation activity of the cells in miR-208a inhibitor group was decreased(P＜0.05),the resistance index was decreased,the apoptotic rate was increased(P＜0.05),and the expression levels of β-catenin,P-gp,and ABCB1 proteins in the cells were decreased(P＜0.05).The dual-luciferase reporter gene assay results showed that SFRP1 was a target gene of miR-208a and miR-208a could negatively regulate the expression of SFRP1.Compared with miR-208a inhibitor+si-NC group,the proliferation activity of the cells in miR-208a inhibitor+si-SFRP1 group was increased(P＜0.05),the resistance index was increased,the apoptotic rate was decreased(P＜0.05),and the expression levels of β-catenin,P-gp,and ABCB1 proteins in the cells were increased(P＜0.05).Conclusion:Downregulation of miR-208a can improve the resistance of the HT-29/5-FU cells to 5-FU by targeting and upregulating the SFRP1 expression,thereby inhibiting the transmission of the Wnt signaling pathway.