Advances of enzymes related to microbial cement / 生物工程学报

Microbial induced calcium carbonate precipitation (MICP) refers to the natural biological process of calcium carbonate precipitation induced by microbial metabolism in its surrounding environment. Based on the principles of MICP, microbial cement has been developed and has received widespread attention in the field of biology, civil engineering, and environment owing to the merits of environmental friendliness and economic competence. Urease and carbonic anhydrase are the key enzymes closely related to microbial cement. This review summarizes the genes, protein structures, regulatory mechanisms, engineering strains and mutual synergistic relationship of these two enzymes. The application of bioinformatics and synthetic biology is expected to develop biocement with a wide range of environmental adaptability and high performance, and will bring the MICP research to a new height.

Application of CT Portography in Esophagogastric Varices in Cirrhotic Patients / 胃肠病学

Background:CT portography(CTP)permits comprehensive evaluation of portal vein and its collateral pathways. It is widely used for assessment of portal hypertension in clinical practice. Aims:To assess the value of CTP in esophagogastric varices in cirrhotic patients. Methods:A retrospective cohort study was performed in 143 cirrhotic patients admitted from Jan. 2013 to Sep. 2015 at the Affiliated Hospital of Qingdao University. All patients fulfilled the inclusion criteria and underwent CTP and gastroscopy within 7 days after admission. According to the occurrence of gastrointestinal bleeding at admission,patients were allocated into two groups:bleeding group( n = 70 ) and non-bleeding group( n = 73 ). Consistency of the results of CTP and gastroscopy was analyzed by kappa coefficient;the accuracy of CTP parameters, including diameters of main portal vein(MPV),splenic vein(SPV)and left gastric vein(LGV)for prediction of variceal bleeding was evaluated by ROC curve. Results:CTP and gastroscopy had a good consistency in typing and grading of esophagogastric varices,with the kappa value of 0. 793 and 0. 775,respectively. The diameters of MPV,SPV and LGV were significantly higher in bleeding group than in non-bleeding group(P < 0. 01),and their area under the ROC curve (AUC)in predicting variceal bleeding was 0. 741,0. 627 and 0. 816,respectively. The accuracy of diameter of LGV was superior to that of MPV and SPV. With the cutoff value of 6. 1 mm,the sensitivity and specificity of diameter of LGV were 65. 71% and 84. 93% ,respectively. With the cutoff value of 16. 3 mm,the sensitivity of diameter of MPV was 75. 71% , which was higher than that of LGV and SPV. Conclusions:CTP can be used in clinical diagnosis of esophagogastric varices in cirrhotic patients,and two CTP parameters,the diameters of LGV and MPV,might be helpful for prediction of variceal bleeding.