In vitro susceptibility of commonly used antibiotics on community-acquired uncomplicated urinary tract infection pathogens in Beijing / 中华泌尿外科杂志

Objective To investigate the distribution and susceptibility patterns of common uropathogens causing community-acquired urinary tract infection (UTI) in Beijing.MethodsA total of 300non-duplicate isolates were randomly collected from 3 hospitals in Beijing between Jan,1 2010 and Mar,312011.Minimal inhibitory concentrations (MICs) were determined by the broth microdilution methods,which were performed and interpreted according to the guidelines established by the Clinical and Laboratory Standards Institute (CLSI).A panel of 8 antimicrobial agents were tested:amikacin,cefaclor,cefepime,cefoperazone/sulbactam,ciprofloxacin,levofloxacin,gentamicin and nitrofurantoin. Fosfomycin trometamol MICs were determined by the agar-dilution method in cation-adjusted MH agar supplemented with glucose 6-phosphate at a concentration of 25 mg/L as detailed in the guidelines issued by 2010 CLSI. All the Escherichia coli,Klebsiella pneumoniae and Proteus mirabilis strains were screened and confirmed by double-disk synergy test for extended-spectrum β-lactamase (ESBLs).Results Among the organisms cultured,E.coli wasthepredominantpathogen(65.0％ ), followedby Enterococcus(11.7％ ),Staphylococcus( 6.3％ ), Klebsiella pneumoniae( 5. 3％ ), Proteus mirabilis( 4. 7％ ), and Pseudomonas aeruginosa (3.0％).Lower susceptibility rates to ciprofloxacin and levofloxacin (31.4％ -47.4％ ) were observed among all the stains.Amikacin,cefoperazone/sulbactam,nitrofurantoin and fosfomycin trometamol were the most active drugs (92.1％,92.1％,88.4％ and 87.9％ susceptible strains,respectively) among the Gram-negative strains.Isolates of Staphylococcus were highly sensitive to amikacin ( 100.0％ ),cefoperazone/sulbactam (94.7％),nitrofurantoin ( 100.0％ ).Higher susceptibility rates to nitrofurantoin (91.4％) and fosfomycin trometamol (90.0％) were observed in Enterococcus.ESBLs-producing strains accounted for 52.3％ (102/195) in E.coli,43.8％ (7/16) in K.pneumoniae and 14.3％(2/14) in P.mirabilis,respectively.ConclusionsResistance is most common to ciprofloxacin and levofloxacin of all the stains.Currently,the most appropriate agents for the empirical management of uncomplicated UTI seems to be amikacin,cefoperazone/sulbactam,nitrofurantoin and fosfomycin trometamol.

Three different drug interaction mathematical models used to evaluate the cytotoxicity of SAHA and arsenic trioxide in combination / 药学学报

To clarify the source of deviations of drug combination effects evaluated with different drug interaction mathematical models, the cytotoxicity of SAHA and arsenic trioxide and their combinations were observed in a series of human cancer cell lines and a normal cell line. The combined effects were evaluated with three drug interaction models: Loewe Additivity (LA), Bliss Independence (BI) and Chou's Median Effect Model. The evaluations with three different models were further compared with each other. We demonstrated that when dose-response curves were fitted with the same method, similar evaluated results for drug combinations would be derived with different models. The deviations of evaluated effects of drug combinations were attributed to different curve fitting methods used rather than the models themselves. The effects of drug combinations showed discrepancies on different cell lines, and at different combined drug concentrations on same cell line.

Application of circular dichroism to the study of interactions between small molecular compounds and DNA / 药学学报

Circular dichroism (CD) is an useful technique for monitoring DNA conformation changes resulting from changes in environmental conditions, such as temperature, ionic strength, and pH, and also for the study of the interaction between DNA and ligands (including small molecules and proteins). CD spectroscopy of DNA arises from the asymmetric backbone sugars and by the helical structures often adopted by nucleic acids. By the interpretation of induced circular dichroism (ICD) of ligand signals resulting from the coupling of electric transition moments of the ligand, DNA bases within the asymmetric DNA environment, ligand-DNA interactions, as well as the DNA-binding mode can be assessed. A number of important conclusions have been reported that related to the observed ICD signals resulting from the interactions between intercalators and groove binders with DNA. If short oligonucleotide sequences are used in the study, sequences-specific of binding also can be deduced. CD determination requires smaller amounts of sample, and not limited by the molecular weight or size and can be performed rapidly; though CD is of low resolution, but it's a complement to NMR and X-ray diffraction methods. This review will introduce the characters of the CD spectra of DNA, and its application to the studies of DNA with small molecules; some progress of the studies in our laboratory will also be discussed. CD is expected to be used as a screening method in seeking more DNA-targeted drugs, such as, antineoplastic, antimicrobial and antiviral drugs.

The interaction between C5aR,C5L2 and chemotaxis inhibitory protein secreted by Staphylococcus aureus / 基础医学与临床

Objective To investigate the mutual effect between G protein-coupled receptors(GPCR)including C5a receptor(C5aR),C5a like receptor 2(C5L2)and chemotaxis inhibitory protein(CHIPs)secreted by Staphylococcus aureus.Methods The purified CHIPs was incubated with HEK 293T cells overexpressing C5aR,C5L2 and C-X-C chemokine receptor type 3(CXCR3).Binding signal was detected by Western blot.Results HEK 293T cells overexpressing C5aR can efficiently bind to CHIPs.No apparent relation between CHIPs and C5L2 or CXCR3 was identified.Conclusion C5aR but not C5L2 is a membrane receptor for binding CHIPs,suggesting a difference between C5aR and C5L2 in association with binding CHIPs.