The necessity and importance of medical equipment quality control are analyzed on the basis of clinical cases of ventilator using.It is necessary because it assures the technical performance in the process of medical diagnosis and treatment.It is important because it extends the work range of medical engineers in hospital,changing them from the state of passive maintenance to active quality control,thus contributing to the combination of engineering and clinical diagnosis and treatment.Further more,it promotes the development of clinical medical engineering in hospital.

Objective To observe the clinical efficacy of plasma exchange(PE),PE combined with plasma bilirubin absorp-tion(PE+PBA),and PE combined with double plasma molecule absorption system(PE+DPMAS),to investigate the best treat-ment options for the patients of hepatitis B-associated subacute severe.Methods Totally 140 patients who had hepatitis B-associat-ed were randomly divided into a PE group,a PE+PBA group,and a PE+DPMAS group.The dinical symptoms and blood rontine, electrolytc and the main biochemical indexes were recorded both before and after treatment and compared among the three groups. Results The total effective rate was higher in the PE +DPMAS group than in the PE group and PE+PBA group,which were 70.8%,60.9%,67.4% respectively,but there was no significant difference(P >0.05).compared with before treatment,serum total bilirubin (TBIL),alanine aminotransferase (ALT),aspartic acid amino shift enzyme (AST),valley aminoacyl transfer peptidase (GGT),alkaline phosphatase (ALP),globulin (GLB)and other biochemical indexes decreased significantly after treatment in 3 groups (P <0.001).PA was increased in the PE group and decreased in the PE+PBA and PE+DPMAS group after treatment,the differences were significant(P <0.05).After treatment,PT was shortened in the PE group,the differences were significant(P <0.05),but there were no significant difference between the PE+PBA and PE+DPMAS groups(P >0.05).Serum K+ and Cl- was obviously declined after treatment in the PE group,there was significant difference(P <0.001).Serum Na+ was obviously declined after treatment between the PE + PBA and PE + DPMAS groups (P < 0.001 ),but the difference was no significant in the PE groups.Serum Ca2+ was significantly decreased in the three groups of patients after treatment(P <0.001).WBC,Hb and PLT were significantly statistical difference after treatment(P <0.05).Conclusion The three groups also can improve liver function and the treatment rate for the patients of subacute hepatitis B-associated severe hepatitis.PE+PBA and PE+DPMAS groups can effective-ly reduce two thirds of the overall usage of the plasma.PE+DPMAS groups that the quantity of Cl- ,Ca2+ ,Hb decline much least in the three groups show larger value in the clinical application.

The knock out vector pHK was constructed with E coli vector pET 28a and shuttle vector pHY300PL, by using denatured DNA and homologous recombination technique, the kanamycin resistance gene ( Kan r) from integrated alkaline protease gene engineering strain BP071 was knocked out successfully, and the 11 positive clones were obtained The yield of the best positive clone BP0715 was stable as same as BP071 The methods provided the good experience for the industrial microbiology research, and it was foundation for studying on the safety of genetically modified organisms