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Objective To investigate the effect of a novel lymphotoxin with selectively binding to p55 tumor necrosis factor receptor (p55TNFR) on myocardial ischemia-reperfusion injury in rats in order to explore the mechanism.Methods A total of 40 SD rats were randomly (random number) assigned into four groups (n =10 in each),namely sham operation group (group A),I/R group (group B),wild type rhLTα treatment group (group C),and p55TNFR selective rhLTα (rhLTα-Q107E) treatment group (group D).After I/R model rats were established,various therapeutic agents or saline were given by continuous intravenous infusion for 24 h via a micropump.After 24 hours of treatment,serum myocardial zymogram,such as aspartate aminotransferase (AST),lactate dehydrogenase (LDH) and creatine kinase (CK),as well as superoxide dismutase (SOD),malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) activities were determined.Myocardial infarction size (MIS) was measured by nitro blue tetrazolium chloride (NBT) staining.Results Compared to sham operation group,MIS,AST,LDH,CK,MDA were increased,while the activities of SOD and GSH-Px were decreased.However,all the effects were significantly reversed by treatment with rhLTα-Q107E (P ＜ 0.05) but not rhLTα (P ＞ 0.05).Conclusions The rhLTα-Q107E plays a role in the protection against myocardial ischemia-reperfusion injury in rats by the mechanism of scavenging oxygen free radicals and increasing the activity of endogenous antioxidant system.
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Objective To analyze the epidemiological characteristic of New Delhi metallo-β-lactamase (NDM)-1-positive bacteria in China and explore its mechanism of drug-resistance.Methods The published papers from 2010 to 2015 about domestic blaNDM-1 were collected and analyzed according to the bacteria species,regional distribution,NDM-1-positive bacteria,infectious source,drug-resistance spectra and transfer mechanism.Results NDM-1-positive bacteria were isola-ted from 25 provinces (municipalities)in China,Guangdong Province was predominant and accounted for 39.49%(P <0.05).The number of Klebsiella pneumoniae and Enterobacter cloacae were predominant in the NDM-1-positive bacteria (P <0.05).Number of patients under the age of ten and among 60 -80 years which infected by NDM-1-positive bacteria were predominant of all the reported patients(P <0.05).The most kinds of samples and diseases were sputum sample (P <0.05)and pulmonary diseases(P <0.05).NDM-1-positive bacteria which found in China had the lowest resistance to amikacin and tigecycline accounted for 7.69% and 2.33%(P <0.05).Conclusion Antibiotic resistant bacteria with NDM-1 resistant gene have become a global public health problem,and significant difference among age,districts and sources,which need active surveillance and more studies to find how it happens and epidemic in the future.
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Objective To study the serotype , biochemical characteristics , virulence gene and multilocus sequence typ-ing(MLST) of S.flexneri 4c in Beijing, Shanghai and Shenyang .Methods Seventy-six strains of S.flexneri 4c isolated from stool samples which had been collected from above-mentioned cities of China were identified with Denka Seiken serum and MASF monoclonal serum .Biochemical characteristics of each strain were identified by API 20E test strip and PCR technology was used for detecting 12 pair virulence genes of S.flexneri.MLST was used to analyze the characteristics . Results The serum agglutination antigen structure of S.flexneri 4c was(Ⅳ:7,8).MASF:B+,Ⅳ:Ⅰ+,7 (8) +.S.flexneri 4c developed different results in biochemical reactions and carried different rates of virulence genes , respectively .The IND test positive rate was 17.11%; MEL weakly positive rate was 3.9%, and ARA test weakly positive rate was 22.37%. Virulence genes were carried at a rate of 89.47% -100%, MLST typing was ST245.Conclusion S.flexneri 4c with serum agglutination antigen structure (Ⅳ:7,8) is a new serotype of S.flexneri.The main biochemical reactions are glucose fermentation and mannitol decomposition .A variety of Shigella related virulence genes are carried .MLST generation is consistent,suggesting that the bacteria might have evolved from ST 270 cloning.
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Objective To study the effect of Dachengqi decoction on expression of triggering receptor on myeloid cell 1(TREM-1)in septic rats in order to further provide a theoretical basis concerning the mechanism of this decoction for treatment of sepsis. Methods 100 male Sprague-Dawley(SD)rats were randomly divided into five groups:normal control,sham operation,sepsis model,low-dose and high-dose Dachengqi decoction groups (each,n=20). The sepsis models were reproduced by cecal ligated perforation(CLP). The low-dose and high-dose Dachengqi decoction groups were lavaged separately by low dose(5 mL/kg)and normal dose(10 mL/kg)Dachengqi decoction at 2 hours before CLP and after CLP twice per day(interval 8 hours),and the other three groups were lavaged with 10 mL/kg normal saline. Five rats in each group were killed randomly at the time points of 6,12,24,48 hours after CLP;the abdominal aorta blood and the liver tissue were collected. The plasma levels of TREM-1,interleukin-6 (IL-6),tumor necrosis factor-α(TNF-α)were tested by enzyme linked immunosorbent assay(ELISA). The expression level of TREM-1 mRNA in the liver was measured by reverse transcription - polymerase chain reaction (RT-PCR). Results Compared with normal control group and sham operation group, the plasma levels of TREM-1, IL-6, TNF-α and the expression of liver TREM-1 mRNA were increased significantly in model group. Compared with model group,the above indexes in low-dose and high-dose Dachengqi decoction groups were reduced obviously,the changes being more marked in the high-dose group;the levels of TREM-1,IL-6 at 6 hours after operation and the levels of TNF-αand TREM-1 mRNA at 24 hours after operation in high-dose group were lower than those of low-dose group〔6 hours TREM-1(ng/L):179.19±4.43 vs. 213.86±2.84,6 hours IL-6 (ng/L):136.80±7.70 vs. 162.90±3.87;24 hours TNF-α(ng/L):71.61±5.07 vs. 108.53±6.29,24 hours TREM-1 mRNA:24.33±3.16 vs. 27.22±3.34,all P<0.05〕. Conclusion The partial mechanism of the efficacy of Dachengqi decoction for treatment of sepsis was probably related to the inhibition of TREM-1 expression.
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OBJECTIVE To detect ESBLs genes in 5 Shigella sonnei isolates.METHODS Susceptibility test to common antibiotics was performed through disk diffusion test,and ESBLs were confirmed according to CLSI.Conjugation experiment was performed to determine whether the resistance was transferable.The ESBLs gene was detected by PCR using universal primers for TEM,SHV,CTX-M,and the PCR products were also directly sequenced and analyzed.At the same time,the five isolates were analyzed by PFGE. RESULTS The five S.sonnei isolates were ESBLs producers and produced CTX-M-15 ESBLs,which were resistant to the most of the ?-lactams such as aztreonam,the first and second generation cephalosporins,cefotaxime,and non ?-lactam such as gentamicin,SF,but susceptible to ceftazidime,the 4th generation cephalosporins,Amikacin and meropenem.These strains were also intermediate to quinolones.CTX-M-15 gene could be transferred through conjugation.PFGE patterns of one isolate were different from the others.CONCLUSIONS Five S.sonnei isolates producing CTX-M-15 ESBLs are resistant to the most antibiotics.Clone spread is evident in these isolates.We should pay more attention to monitor these strains.