RESUMO
The antibacterial activity and mechanism of the antimicrobial peptide mutant Cbf-14-2 against NDM-1 carrying recombinant bacteria (E.coli BL21 (DE3)-NDM-1) was investigated in this study.The minimum inhibitory concentration (MIC),minimum bactericidal concentration (MBC) and killing curves (KCs) in vitro were determined by the broth microdilution method.Mice septicemia model was established by interaperitotoneal injection of E.coli BL21 (DE3)-NDM-1 to evaluate the antibacterial activity of this peptide in vivo.Results showed that Cbf-14-2 exhibited a potent antibacterial activity with MIC of 16 μg/mL and killed almost all recombinant bacteria within 120 min.Meanwhile,it significantly improved the survival rate of infected mice up to 70％ with the decreasing of bacterial load in mice lung,liver,spleen and kidney.This powerful clearance ability of Cbf-14-2 against bacteria mainly related to its enhanced membrane penetration ability through neutralizing the negative charges and disrupting the integrity of the bacterial cell membrane.Therefore,Cbf-14-2 is expected to be a potential antimicrobial agent for the treatment of infection induced by multi-drug resistant bacteria,especially for the NDM-1carrying bacteria.
RESUMO
Objective To observe the change in IL-1β,IL-13mRNA expression in drowning rat lungs and serum,so as to investigate the significance of IL-1β and IL-13 mechanism in the development of drowning.Methods SD rats were randomly divided into control group,drowning group.Then using TaqMan probe method to determine the expression of IL-1β and IL-13 mRNA in Right lower lobe of lung tissue and the serum of right ventricle,which were extracted respectively from each group of rats.Results (1) The lung tissue morphological changes:Typical appearance signs and anatomy of drowning group meet ante-mortem drowning feature.(2) The expression of IL-1β,IL-13 in lung tissue:compared with the control group,the expression of IL-1β and IL-13 were slightly decreased,which has no statistical significance.(3) The expression of IL-1β and IL-13 in serum:compared with the control group,the expression of IL-1β and IL-13 were significant increased,both of which has statistical significance.Conclusion (1)The expression of IL-1β and IL-13 were decreased in lung tissue may be due to drowned rats present compensatory anti-inflammatory response syndrome which causes immune incompetent performance.(2) The expression of IL-1β and IL-13 were significant increased in serum may be relate to drown stress and drowning associated acute lung injury after traumatic stress.
RESUMO
Objective To evaluate the effects of dexmedetomidine on perioperative pulmonary compliance and the expression of Toll?like recep?tor(TLR)?2 and TLR?4 in the peripheral blood during perioperative period in patients undergoing open colorectal cancer radical surgery. Meth?ods Twenty patients with colorectal cancer underwent elective general anesthesia,with ASA gradeⅠ?Ⅱand body mass index(BMI)<30 kg/m2, aged 30 to 68 years old,were enrolled for the study. They were randomly divided into control group(group C,n=10)and dexmedetomidine group (group D,n=10). In group D,dexmedetomidine was infused at a rate of 0.4μg·kg-1·h-1 from the beginning of surgery till 30 min before the end of surgery. The patients in group C received same manipulation as in group D except dexmedetomidine was replaced by normal saline. The mean ar?terial pressure(MAP)and heart rate(HR)were recorded before anesthesia induction(T0),30 min(T2),60 min(T3),and 90 min(T4)after the beginning of surgery,extubation(T6),and 3 min after extubation(T7). Airway pressure and lung dynamic compliance were recorded at T1?T7 time points,respectively. Vein blood samples were drawn to analyze the TLR?2,TLR?4 and tumor necrosis factorα(TNF?α)concentration at T0,T4,T7 and the day after operation(T8),respectively. Results Compared with group C,MAP and HR increased in group D at T6(P<0.05);lung dynamic compliance increased in group D at T4(P<0.05);TLR?2 and TLR?4 concentration in serum decreased in group D at T4, T7 and T8(P<0.05);TNF?αconcentration in serum decreased in group D at T4,T7 and T8(P<0.05). Conclusion Continuous infusion of 0.4μg·kg-1·h-1 dexmedetomidine can help to stabilize hemodynamics,relieve inflammatory stress response,maintain the relative stability of intra?operative hemodynamic parameters,and also can improve the pulmonary dynamic compliance of patients.