Study on the transfer mechanism and destructive law of the bacterial antibiotic resistance genes disinfected by chlorination / 中华预防医学杂志

Objective@#To study the response of Escherichia coli (E. coli) HB101 (plasmid pUC19) and its carried antibiotic resistance genes to the process of cholorination under different environmental conditions.@*Methods@#The E. coli strain was reacted with sodium hypochlorite at the concentration of 0.5, 0.75, 1.00, and 0.55 mg/L, then the residual chlorine and the colonies were detected at the 0.25, 1, 2, 5, 10, 20, and 30 min of the reaction, respectively. The first order disinfection kinetic model and EFH model were used to evaluate the inactivation effect of E. coli (plasmid pUC19) treated by sodium hypochlorite, while the plasmid pUC19 and antibiotic resistance gene ampr were detected by PCR method. Besides, the logarithm of Ct (residual chlorine in t) under different concentration were calculated.@*Results@#The temperature and pH value played important roles on the inactivation of E. coli and elimination of plasmid pUC19 and ampr under the function of sodium hypochlorite. The Ct value needed for 5-log of E.coli HB101(pUC19) inactivation at 4, 20, 36 ℃ was 11.92, 10.28, 7.67, respectively, and when the pH was in 6.0, 7.0, 8.0, with chloride concentration were 0.75, 0.70, 0.55 mg/L, the Ct value needed for reached to 6.68, 10.28, 15.73 min·mg/L. At pH 7.2 condition, when the temperature was 4, 20, 36 ℃, and chloride concentration were 9, 5, 3 mg/L.The required Ct values to completely destroy the transformation function of free antibiotic resistant plasmids were 36.11, 34.17,16.09 min·mg/L. Sodium hypochlorite disinfection can release free ampr gene and even the transformed plasmid pUC19, and pollute the water body. Only when the Ct value reached 903.03 min·mg/L, the complete ampr gene can be destroyed which was far more exceed the bacterial lethal Ct value.@*Conclusion@#Even if all the antibiotic resistant bacteria were inactivated, the antibiotic resistant plasmids or genes might still maintain complete with the transformable function, which may result in new potential risks of waterborne diseases.

Meta Analysis of the relationship between serum adenosine deaminase and acute,chronic hepatitis / 中国综合临床

Objective To evaluate the role of serum adenosine deaminase in the diagnosis and treatment of acute,chronic hepatitis.Methods WanFang Data,CNKI and PubMed were retrieved in order to screen literature about the relationship between serum ADA and acute and chronic hepatitis,the retrieval time was from the beginning of the database to December 1st,2016.After evaluating quality of the included studies, the meta-analysis was conducted to analyze the relationship between the level of serum ADA and acute,chronic hepatitis via RevMan 5.2 software.Results A total of 28 articles were identified including 1688 cases with acute hepatitis and 1843 cases with chronic hepatitis.The results of meta-analysis showed that the levels and positive rate of serum ADA were significantly higher in the acute hepatitis groups than that in chronic hepatitis groups(MD=4.13,95%CI(0.43,7.84),P=0.03;OR=1.94,95%CI(1.19,3.14),P=0.007).Funnel plots showed significant publication bias,and may have implications for Meta analysis(P=0.001).Conclusion Heterogeneity of the literatures mainly comes from the clinical heterogeneity and statistical heterogeneity.The serum ADA has certain value in the diagnosis and treatment of acute and chronic hepatitis.

Mechanism of Escherichia coli injury under UV disinfection / 军事医学

Objective To study the inactivation kinetics and injury mechanism of Escherichia coli under UV disinfection in drinking water.Methods The inactivation kinetics of E.coli ATCC 25922 was determined by plate count methods in the UV disinfection experiment.The morphology,cell membrane permeabilization and injury of biological macromolecules were observed under a transmission electron microscope (TEM).The rate of ONPG hydrolysis and changes in activities of antioxidant enzymes were observed Raman spectroscopy.Results the changes of damaged cells involved morphological damage such as loss of the structural integrity of the wall and membrane,condensation of cellular material and leakage of significant amounts of cytoplasmic material,a more than four-fold increase of cell membrane permeabilization and damage to the structure of protein,nucleic acids and phospholipid.Conclusion UV disinfection can lead to a multi-target damage.

Practice of Grade Protection Assessment on the Hospital Information System / 医学信息学杂志

Starting from the practices of grade protection assessment on the information system of Peking Union Medical College Hos -pital, the paper introduces the information system grade and assessment contents and processes , discusses common problems found in specific work and risk analysis approaches so as to provide a reference for work related to information security .

Construction and evaluation of reference standards for detection and quantification of Klebsiella pneumoniae using real-time PCR / 药物分析学报

Objective To construct reference standards for detection and quantification of Klebsiella pneumoniae (K.pneumoniae) with SYBR Green I-based real-time PCR assay. Methods Primers were designed based on the published sequence of the phoE gene of K.pneumoniae. The standard was prepared by cell culture, PCR and T-A clone methods, and was identified by colony PCR and DNA sequencing. Results The standard curve showed a very good linear negative regression between threshold cycle (Ct) and Log starting quantity of copy number. The detection range was from 5.2 to 5.2×106 copies per reaction, and the detection limit was 6 copies per reaction. The coefficients of variance (CVs) of three parallel experiments were in the range of 0.05%-0.91%. Conclusion The reference standards have high stability and reproducibility. They can be used in the quantitative detection of K.pneumoniae.

Operative stress response, energy metabolism, and visceral proteins after laparoscopic-assisted resection of rectal carcinoma / 中国微创外科杂志

Objective To compare the differences between laparoscopic-assisted and open resection of rectal carcinoma in respect of peri-operative levels of C-reactive protein (CRP), rest energy expenditure (REE), and visceral proteins. Methods According to patients' choice of operation, either laparoscopic-assisted (n=20, Laparoscopic Group) or open (n=25, Open Group) resection of rectal carcinoma was performed. The levels of CRP and visceral proteins-including albumin (ALB), prealbumin (PRE), transferrin (TRF), and retinal-binding protein (RbP)-were assayed preoperatively and on the 1st, 2nd, and 3rd day postoperatively. The levels of REE were also measured by indirect calorimetry in the morning. Results Compared with the preoperative period, the CRP levels in both groups were significantly increased on the 1st, 2nd, and 3rd day (P0.05). The levels of PRE in the Laparoscopic Group were significantly higher than those in the Open Group on the 2nd postoperative day (P

The Mechanism of Al_2O_3 Nanoparticle Influence on RP4-mediated Conjugation:a Preliminary Research in Bacterium Morphology / 环境与健康杂志

Objective To explore the influence of Al2O3 nanoparticle (20nm in average) on RP4-mediated conjugation and its mechanism was explored further. Methods Mating was conducted between E.coli HB101(RP4) and Salmonella aberdeen Kauffmann 50312(strR) in saline at 25 ℃ without stirring for 8 h,the concentrations of Al2O3 nanoparticle were 0.005,0.05,0.5,5,50 mmol/L respectively. The initial concentration of donor and recipient were both about 109 cfu/ml(donor per recipient ratio was 1∶3).Later transmission electron microscope(TEM) and laser scan confocal microscope (LSCM) were exploited to investigate cell morphology and structure. Results 5 mmol/L and 50 mmol/L Al2O3 nanoparticle could increase the conjugal transfer frequency by 150-fold and 40-fold respectively. TEM observation on thin section indicated several bacterial were prone to form conjugational junction together in 5 mmol/L and 50 mmol/L Al2O3 nanoparticle treated group,which was rarely seen in control group. Meanwhile the cell envelope of bacterial was significantly damaged upon the treatment by 50 mmol/L Al2O3,which might be the reason why transfer frequency of 50 mmol/L Al2O3 group was less than 5 mmol/L Al2O3 group. LSCM result indicated that Al2O3 nanoparticle might damage cell envelope and the damage was positively related to the accumulation of Al2O3 in bacterial. Conclusion Al2O3 nanoparticle can stimulate RP4 conjugal transfer. Conjugative gene is highly regulated. Al2O3 nanoparticle might modulate conjugative gene expression directly or influence cell membrane permeability and thus modulate the process of conjugation indirectly .