Objective:To analyze the effects of espO gene knockout on the biological characteristics of enterhemorrhagic Escherichia coli (EHEC). Methods:Two-step methods mediated by the suicide plasmid pCVD442-Δ espO and plasmid pTrc99a were used to construct the espO gene-deleted strain (Δ espO) and the complemented mutant (CΔ espO), respectively. HeLa cells were infected with different EHEC strains to analyze the biological functions and lethal effects of espO gene during infection. Results:PCR, electrophoresis and gene sequencing showed that the Δ espO and CΔ espO mutants were successfully constructed. Compared with the wild-type strain, neither the Δ espO nor CΔ espO mutant showed significant difference in growth rate, indicating that the espO gene had no influence on the growth and replication of EHEC. Furthermore, EspO could activate the tumor necrosis factor receptor (TNF)-induced NF-κB signaling pathway, while the effector protein NleB could inhibit the process. EspO could not inhibit the death of HeLa cells induced by TNF or TNF-related apoptosis-inducing ligand (TRAIL) after EHEC infection. Conclusions:In this study, we successfully constructed the espO gene-deleted and complemented mutants of EHEC and preliminarily analyzed the interaction between espO gene and host cells and the effects of espO gene on cell apoptosis during infection, which provided reference for further research on the in vitro biochemical activity and in vivo pathogenic roles of EspO.

ObjectiveTo investigate the clinical effect of vitamin E in the treatment of nonalcoholic fatty liver disease (NAFLD) in children. MethodsPubMed, Web of Science, The Cochran Library, Embase, OVID/NEJM, CNKI, and Wanfang Data were searched for the articles on vitamin E in the treatment of NAFLD in children published up to December 2019. The data of 8 parameters were analyzed, i.e., body mass index (BMI), liver enzymes ［alanine aminotransferase (ALT) and aspartate aminotransferase (AST)］, blood lipid levels ［triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL), and high-density lipoprotein (HDL)］, and remission rate of hepatic steatosis. RevMan 5.3 was used to perform a Meta-analysis. Continuous variables were analyzed by standardized mean difference (SMD) and 95% confidence interval (CI), and the changes after intervention were analyzed; categorical variables were analyzed by risk difference (RD) and 95%CI. A fixed effects model was used for homogeneous data, and a random effects model was used for heterogeneous data. Funnel plots were used to evaluate publication bias. ResultsA total of 599 articles were retrieved, among which 9 were included in the Meta-analysis, with 607 subjects in total. Vitamin E significantly improved the level of ALT (SMD = -0.27, 95%CI: -0.48 to -0.06, P=0.01), but it did not improve the levels of BMI (SMD=-0.09, 95%CI: -0.28 to 0.10, P=0.34), AST (SMD=-020, 95%CI: -0.42 to 0.02, P=0.07), TG (SMD=-0.19, 95%CI: -0.51 to 0.12, P=0.22), TCHO (SMD=-0.11, 95%CI: -0.31 to 0.08, P=0.24), HDL (SMD=-0.02, 95%CI: -0.27 to 0.23, P=0.88), LDL (SMD= -0.04, 95%CI: -0.27 to 019, P=072), and the remission rate of hepatic steatosis (RD=0.06, 95%CI: -0.05 to 0.17, P=0.29). ConclusionVitamin E can significantly improve the level of ALT in children with NAFLD and can be considered as an adjuvant drug for clinical treatment.

【Objective】 To develop an assay to determine β-lactam antibiotics using microcolumn gels and to study the β-lactam antibiotics present in the blood of patients and their clinical significances. 【Methods】 446 patients with a history of taking β-lactam antibiotics from January 2019 to June 2019 were randomly selected from Trauma Emergency Center, Department of Arthrosis, Department of Spine and Department of Bone Oncology of our hospital, and 4 mL(per capita) venous blood was collected. Irregular antibody screening, anti-globulin detection and drug antibody determination were performed by microcolumn gel method. The data of gender, age, disease, blood transfusion history and medication were collected. The test results and clinical data were retrospective analyzed. 【Results】 The yielding rate of antibody was 0.45%(2/446) in patients with a history of taking β -lactam antibiotics. 16.38%(73/446) of the samples were positive in direct antiglobulin test, and 64.38%(47/73) of them did not agglutinate with RBCs treated with drugs. The yielding rate of specific antibodies against drug was 4.93%(22/446), and the titer ranged from 2 to 128(8). 1 case of auto-IgM antibody, 1 case of blood group related antibody and 2 cases of non-specific protein adsorption were detected. The yielding rate of drug antibody in patients with blood transfusion history reached to 12.10 %(22/124), so it was also high in patients with bone tumor. 【Conclusion】 Direct antiglobulin assay is helpful for the detection of β-lactam antibodies. The negative results of antibody screening cannot completely exclude the presence of drug antibodies. The yielding rate of drug antibody can be greatly improved by specific drug antibody detection, and it was higher in transfused patients relative to non-transfused one.