ABSTRACT
Objective:To investigate the in vitro antibacterial effects of imipenem combined with common antibiotics on bla KPC-2 type carbapenem resistant klebsiella pneumoniae (CRKP) targeting bla KPC-2 gene. Methods:Six strains of unrepeated bla KPC-2 type confirmed by polymerase chain reaction and DNA sequence were isolated in Yueqing People's Hospital, China between January 2018 and January 2019 were included in this study. The susceptibility rate of imipenem against nine conventionally used antibiotics was determined. The sensitivity test of imipenem combined with eight antibiotics was performed with the checkerboard method. Fractional inhibitory concentration was calculated to assess the efficacy of imipenem combined with common antibiotics. The in vitro treatment time-antibacterial effect curve was drawn to evaluate the antibacterial effects. Results:The resistance rate of six strains of bla KPC-2 type was 100.00% (6/6) for imipenem, meropenem, ceftazidime, ciprofloxacin, rifampicin and cefotaxime, and it was 66.67% (4/6) for minocycline and clavulanic acid and 33.33% (2/6) for tigecycline. Imipenem combined with tigecycline had a better antibacterial effect and exhibited a synergistic effect on four strains of bla KPC-2 type CRKP and an additive effect on two strains of Bla KPC-2 type CRKP. The curve of time for in vitro treatment of KPN2 with imipenem combined with tigecycline against bactericidal effect revealed that the antibacterial rate of imipenem at the 1/2 minimum inhibitory concentration combined with tigecycline at the 1/4 minimum inhibitory concentration was > 95% at (t+2) and the antibacterial effect could maintain (t+10) hours to (t+12) hours. The antibacterial rate of imipenem combined with tigecycline against strain 002 was gradually decreased with time, and the growth curve of strain 002 rised gradually. Conclusion:In vitro drug sensitivity test revealed that imipenem combined with tigecycline exhibits a good synergistic effect on bla KPC-2 type CRKP. Findings from this study provide a reference for clinical treatment of bla KPC-2 type CRKP.
ABSTRACT
Objective To study the ginseng polysaccharides for prolonging the life span of the C.elegans and inhibit the toxic effects of polyQ accumulation.Methods Caenorhabditis elegans of HA759 and AM141 were divided into control group and Ginseng group, seprately.Control group didn’ t do any special treatment, Ginseng group were given 10 mg/mL polysaccharide and OP50-1 in the proportion of 1:4 mixed volume to 50 mL.C.elegans of glutamine ( polyQ) polymer HA759 neurotoxicity model test of glutamine protein polymer toxicity experiment were done.The ASH neuron survival condition were tested.After sampling statistics gathered nematodes in the whole fluorescent points every day, study ginseng polysaccharide on polymers glutamine aggregation inhibition.Finally the solid life of two C.elegans were studied.Results The survival rate of ASH neurons in Caenorhabditis elegans HA759 of control group after 3 days culture was 53%.which of Ginseng group was 64% (P<0.05).The fluorescence of 48~96h aggregation points in Caenorhabditis elegans AM141 of control group were(6 ±1), (27 ±2), (56 ±4), which of Ginseng group were (4 ±1) in 48 h, (20 ±3) in 72 h and (45 ±2) in 96 h, the differences between two groups were all significant(P <0.05).The average survival time of Caenorhabditis elegans AM141 of control group was (23 ±2)days, which of Ginseng group was (27 ±2)days;average survival time of Caenorhabditis elegans HA759 of control group was (24 ±2)days, which of Ginseng group was (27 ±2)days,the difterences were all signiyicant(P<0.05).Conclusion Ginseng polysaccharides can not only prolong the lifespan of the C.elegans, but also can restrain polyQ gathered and ease the polyQ neurotoxicity associated with aging.
ABSTRACT
Objective To evaluate the efficacy of high performance liquid chromatography (HPLC) for simultaneous determination of propofol and remifentanil concentrations in human plasma.Methods Methods Eighteen healthy volunteers of both sexes,aged 18-45 yr,weighing 52-81 kg,were enrolled in the study.Venous blood samples were collected,and the concentrations of propofol and remifentanil in human plasma were detected simultaneously by HPLC.The internal standard was thymol.Potassium dihydrogen phosphate 0.1 mol/L was added to the plasma and then the plasma samples were extracted with extract liquor (ethyl acetate ∶ hexane =4 ∶ 1,V/V).The analytical column was ZORBAX Eclipse XDB-C18 (4.6 mm×250 mm,5 μm).The mobile phase was methano ∶ 0.02 mol/L NaH2PO4 ∶ acetonitrile,the flow rate was 1.0 ml/min,the detection wavelength was 210 nm within 1-7 min,and 266 nm within 7-16 min,and the sample size was 20 μl.Linear regression analysis was performed by using the least-squares method.The specimens of the blood with the final concentration of remifentanil 1.00,5.00 and 20.00 ng/ml and propofol 0.50,2.00 and 10.00 μg/ml were obtained to determine the recovery,precision and stability.Results Linear regression equation of remifentanil was C=12.853 5Ai/As+0.084 8 (R2 =0.999 4),and this system showed a good linear relationship with the concentration of remifentanil ranged 0.5-40.0 ng/ml.Linear regression equation of propofol was C=8.554 3 Ai/As+0.029 1 (R2=0.998 6),and this system showed a good linear relationship with the concentration of propofol ranged 0.2-20.0 μg/ml.For both propofol and remifentanil concentrations,the relative recovery was within the range of 85％-115％,the absolute recovery was larger than 75％,and the relative standard deviation of intra-and inter-day precision and stability was less than 5％.The method was proved to meet the requirements of biological sample analysis.Conclusion For HPLC method established in this trial,the determination is sensitive,reproducible,rapid and simple,and it can be used for simultaneous determination of propofol and remifentanil concentrations in human plasma and for clinical pharmacokinetic research.