This study aims to investigate the biological function of the Clumping factor B(clfB)gene in Staphylococcus aureus.The recombinant plasmid pBT2-△clfB was constructed and elec-troporated into Staphylococcus aureus J57 to delete clfB by homologous recombination.The ex-pression plasmid pLI50-clfB was constructed,modified,and electroporated into clfB gene deletion strain △clfB and constructed a complementation strain(C△clfB).J57,△clfB,and C△clfB were cultured at 37℃ for 12 h,and the growth curves of each strain were plotted.The hemolytic properties of each strain were analyzed by contact method,the motility of each strain on TSA plates was determined,and the autolysis rate of each strain under the action of TritonX-100 was determined.Crystal violet staining was used to detect each strain's biofilm formation ability,and biofilm components formed by each strain were quantitatively analyzed.The K-B method was used to determine the sensitivity of each strain to commonly used antibiotics.ClfB gene deletion strain△clfB and the complemented strain C△clfB were successfully constructed.The growth curves of the deletion strain were almost consistent with those of the wild and complemented strains,and there was no significant difference.Compared with J57 and C△clfB,the hemoly ability and the athletic of △clfB decreased.In the condition of TritonX-100,the autolysis rate of △clfB was significantly lower than that of J57 and C△clfB(P＜0.01).Compared with J57 and C△clfB,the ability of △clfB to form biofilm was significantly lower than that of J57 and C△clfB(P＜0.05),and the content of extracellular DNA and protein in the biofilm was significantly decreased.In con-trast,the content of soluble polysaccharides was significantly increased(P＜0.05).Compared with J57 and C△clfB,△clfB was more sensitive to chloramphenicol,gentamicin,and kanamycin while more resistant to linezolid.ClfB gene is closely related to the autolysis,hemolytic activity,athlet-ic,and biofilm formation ability of Staphylococcus aureus,affecting the sensitivity of bacteria to certain antibiotics.

This study aims to investigate the biological function of the Clumping factor B(clfB)gene in Staphylococcus aureus.The recombinant plasmid pBT2-△clfB was constructed and elec-troporated into Staphylococcus aureus J57 to delete clfB by homologous recombination.The ex-pression plasmid pLI50-clfB was constructed,modified,and electroporated into clfB gene deletion strain △clfB and constructed a complementation strain(C△clfB).J57,△clfB,and C△clfB were cultured at 37℃ for 12 h,and the growth curves of each strain were plotted.The hemolytic properties of each strain were analyzed by contact method,the motility of each strain on TSA plates was determined,and the autolysis rate of each strain under the action of TritonX-100 was determined.Crystal violet staining was used to detect each strain's biofilm formation ability,and biofilm components formed by each strain were quantitatively analyzed.The K-B method was used to determine the sensitivity of each strain to commonly used antibiotics.ClfB gene deletion strain△clfB and the complemented strain C△clfB were successfully constructed.The growth curves of the deletion strain were almost consistent with those of the wild and complemented strains,and there was no significant difference.Compared with J57 and C△clfB,the hemoly ability and the athletic of △clfB decreased.In the condition of TritonX-100,the autolysis rate of △clfB was significantly lower than that of J57 and C△clfB(P＜0.01).Compared with J57 and C△clfB,the ability of △clfB to form biofilm was significantly lower than that of J57 and C△clfB(P＜0.05),and the content of extracellular DNA and protein in the biofilm was significantly decreased.In con-trast,the content of soluble polysaccharides was significantly increased(P＜0.05).Compared with J57 and C△clfB,△clfB was more sensitive to chloramphenicol,gentamicin,and kanamycin while more resistant to linezolid.ClfB gene is closely related to the autolysis,hemolytic activity,athlet-ic,and biofilm formation ability of Staphylococcus aureus,affecting the sensitivity of bacteria to certain antibiotics.

Objective To systematically compare the combined spinal-epidural block versus epidural block for labor analgesia.Methods PubMed,Embase,Cochrane Library and Web of Science were searched for randomized controlled trials involving the comparison of combined spinal-epidural block versus epidural block for labor analgesia from the date of database establishment up to September 2016.Evaluation indexes included visual analog scale scores (at 5,10 and 15 min after analgesia),onset time of analgesia,duration of analgesia,duration of the second stage of labor,cesarean section and assisted vaginal delivery,development of Apgar scores of the neonates＜7 (at 1 and 5 min after birth) and occurrence of adverse reactions.The quality of the trials was evaluated according to Cochrane Handbook 5.1.0 criteria,and meta-analysis was conducted using the Cochrane Collaboration's RevMan 5.3 software.Results Twenty studies involving 6 297 patients were included in this meta-analysis.Compared with group epidural block,visual analog scale scores were significantly decreased at 5,10 and 15 min after analgesia,the onset time of analgesia was shortened,and the incidence of pruritus and hypotension was increased in group combined spinalepidural block (P＜0.05).Conclusion Compared with epidural block,although the combined spinalepidural block has faster onset,the adverse effects are more when used for labor analgesia.

Objective To evaluate the effect of sufentanil postconditioning on renal ischemia-reperfusion (I/R) injury in rats and the relationship with autophagy.Methods Thirty pathogen-free healthy adult male Wistar rats,aged 6-8 weeks,weighing 180-220 g,were divided into 3 groups (n=10 each)using a random nunber table:sham operation group (group S),group I/R and sufentanil postconditioning group (group SP).The left renal pedicle was clamped for 45 mnin with an atraumatic vascular clamp followed by reperfusion,and the right kidney was removed immediately after onset of reperfusion in anesthetized rats to establish the model of renal I/R injury in I/R and SP groups.In group S,the left renal pedicle was only isolated,and the right kidney was removed.Sufentanil 1 μg/kg was injected via the tail vein at 5 min before reperfusion in group SP,while the equal volume of normal saline was given instead in S and I/R groups.At 24 h of reperfusion,blood samples were collected by cardiac puncture for measurement of serum creatinine (Cr) and blood urea nitrogen (BUN) concentrations.The animnals were then sacrificed,and the left renal specimens were obtained for examination of pathological changes (with light microscopes) and for determination of the expression of microtubule-associated protein 1 light chain 3 (LC3) and Beclin-1 in renal tissues (by immuno-histochemistry).Results Conpared with group S,the serum Cr and BUN concentrations were significantly increased,and the expression of LC3 and Beclin-1 in renal tissues was up-regulated (P＜0.05),and the pathological changes of kidneys were aggravated in I/R and SP groups.Compared with group I/R,the serum Cr and BUN concentrations were significantly decreased,the expression of LC3 and Beclin-1 in renal tissues was down-regulated (P＜0.05),and the pathological changes of kidneys were significantly attenuated in group SP.Conclusion Sufentanil postconditioning can attenuate renal I/R injury,and the mechanism may be related to inhibition of autophagy in rats.

Objective To evaluate the effect of oxycodone pretreatment on cell apoptosis during renal ischemia-reperfusion (I/R) in rats.Methods Thirty-six healthy male Wistar rats,weighing 180-220 g,aged 6-9 weeks,were divided into 3 groups (n=12 each) using a random number table:sham operation group (group S),renal I/R group (group I/R) and oxycodone pretreatment group (group O).The left renal pedicles were clamped with atraumatic microclips for 45 min followed by reperfusion,and the right kidney was removed immediately after onset of reperfusion to establish the model of renal I/R injury in I/R and O groups.At 10 min before ischemia,oxycodone 0.5 mg/kg was injected via the tail vein in group O,while the equal volume of normal saline was given via the tail vein instead of oxycodone in I/R and S groups.Blood samples were collected by cardiac puncture at 24 h of reperfusion for measurement of serum blood urea nitrogen (BUN) and creatinine (Cr) concentrations.The animals were then sacrificed,and the left renal specimens were obtained for examination of the pathological changes (with a light microscope) and for determination of the expression of Bcl-2,Bax and caspase-3 in renal tissues (by immunohistochemistry).Bcl-2/Bax ratio was calculated.Results Compared with group S,the serum Cr and BUN concentrations were significantly increased,the expression of Bcl-2,Bax and caspase-3 in renal tissues was up-regulated,and the Bcl-2/Bax ratio was decreased in I/R and O groups (P＜0.05).Compared with group I/R,the serum Cr and BUN concentrations were significantly decreased,the expression of Bcl-2 in renal tissues was up-regulated,the expression of Bax and caspase-3 in renal tissues was down-regulated,the Bcl-2/Bax ratio was increased (P＜0.05),and the pathological changes were significantly attenuated in group O.Conclusion The mechanism by which oxycodone pretreatment reduces renal I/R injury may be related to inhibition of cell apoptosis in rats.

Objective To evaluate the effect of oxycodone pretreatment on autophagy during renal ischemia-reperfusion (I/R) in rats.Methods Thirty-six SPF healthy adult male Wistar rats,aged 6-9 weeks,weighing 180-220 g,were divided into 3 groups (n=12 each) using a random number table:sham operation group (Sham group),I/R group and oxycodone pretreatment group (Oxy group).The left renal pedicles were clamped with atraumatic microclips for 45 min followed by reperfusion to establish the model of renal I/R injury in I/R and Oxy groups.Oxycodone 0.5 mg/kg was injected via the caudal vein at 15 min before ischemia in group Oxy,and the equal volume of normal saline was given instead in I/R and Sham groups.At 24 h of reperfusion,blood samples were collected from hearts for measurement of serum creatinine (Cr) and blood urea nitrogen (BUN) concentrations.The animals were then sacrificed and left renal tissues were obtained for examination of pathological changes (with a light microscope) and for determination of Bcl-2 and Beclin-1 expression (by immunohistochemistry).Results Compared with Sham group,the concentrations of serum Cr and BUN were significantly increased,and the expression of Bcl-2 and Beclin-1 in renal tissues was up-regulated at 24 h of reperfusion in I/R and Oxy groups (P<0.05).Compared with I/R group,the concentrations of serum Cr and BUN were significantly decreased,the expression of Bcl-2 in renal tissues was up-regulated,and the expression of Beclin-1 in renal tissues was down-regulated at 24 h of reperfusion (P<0.05),and the pathological changes were significantly attenuated in Oxy group.Conclusion Oxycodone pretreatment inhibits autophagy through up-regulating the expression of Bcl-2 and down-regulating the expression of Beclin-1,thus attenuating renal I/R injury in rats.

Objective To evaluate the effect of dexmedetomidine on lipid peroxidation during lung ischemia-reperfusion (I/R) in rats.Methods Fifty-four pathogen-free healthy male Wistar rats,weighing 250-350 g,were randomly divided into 3 groups (n=18 each) using a random number table:sham operation group (S group),I/R group,and dexmedetomidine group (Dex group).In group Dex,dexmedetomidine 5 μg/kg was injected via the caudal vein once a day for 2 consecutive days.The equal volume of normal saline was given in S and I/R groups.At 30 min after administration on 2nd day,lung I/R was produced by clamping the left hilum of lung for 45 min followed by 120 min of reperfusion in I/R and Dex groups.At 45 min of ischemia,and 60 and 120 min of reperfusion,6 rats selected from each group were sacrificed,and the left lungs were removed for examination of the pathological changes and for determination of wet/dry lung weight ratio (W/D ratio),malondialdehyde (MDA) content and superoxide dismutase (SOD) activity.Results Compared with S group,the SOD activity was significantly decreased,and the MDA content and W/D ratio were significantly increased at 60 and 120 min of reperfusion in I/R and Dex groups (P＜0.05).Compared with I/R group,the SOD activity was significantly increased,and the MDA content and W/D ratio were significantly decreased at 60 and 120 min of reperfusion in Dex group (P＜0.05).The pathological changes of lungs were significantly attenuated in Dex group as compared with I/R group.Conclusion Dexmedetomidine mitigates lung I/R injury through inhibiting lipid peroxidation in rats.