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Three kinds of 4-hydroxycoumarin derivatives, namely, biscoumarins (1-4), epoxydicoumarins (5-8) and dihydropyrans (9-12), were synthesized and the antibacterial activity of each of them was evaluated. The result of preliminary bioassay shows that the lowest minimal inhibitory concentration (MIC) of compounds 1 and 2 against drug-sensitive S. aureus (ATCC 29213) and methicillin-resistant S. aureus (MRSA XJ 75302, Mu50, ATCC 700699 and USA 300) is 4-64 ug/mL. Additionally, there are two classical intramolecular O-H⋯O hydrogen bonds (HBs) in the structures of biscoumarins (1-4), and their corresponding HB energies were further calculated by the density functional theory (DFT) [B3LYP/6-31G*] method. [ABSTRACT FROM AUTHOR]

Objectives Due to the increasing prevalence of drug-resistant S taphylococcus aureus infection, we develop novel 4-hydroxycoumarin derivatives as antimicrobials. Methods The antibacterial activity of 4-hydroxycoumarin derivatives against drug-susceptive S . aureus ( ATCC 29213) and methicillin-resistant S . aureus ( MRSA) were evaluated using minimal inhibitory concentration ( MIC) assay; the activity of favourable compound was further observed using bacterial growth curves assay and in the MRSA infection mice. Key findings Compared with dihydropyran derivatives, compound 1 as one of biscoumarins showed most potent activity with MIC values of 4-8 μg/ml and apparently inhibited the growth rate of S . aureus ATCC 29213 and USA300 strain in concentrations of both 16 and 32 mg/ml. In the mice infected with MRSA USA300, administration of 5 mg/kg compound 1 improved the animal survival rate to 66.7%, and improved the pathological change in lung tissue compared with the infection model animals. No significant cytotoxicity of compound 1 was observed on the umbilical vein endothelial cells ( HUVECs) under the concentration of 800 μg/ml. Conclusion Compared with the dihydropyran derivatives, biscoumarins exhibited more promising activity against both drug-sensitive and drug-resistant S . aureus, and it is efficacious in treating MRSA infections in mouse models with a favourable safety in human cells. [ABSTRACT FROM AUTHOR]

To find potential enhancers for facilitating the buccal delivery of insulin, a TR146 cell-culture model of buccal epithelium, cultured on commercially available insert plates, was used to evaluate the permeability-enhancing effects of several traditional and new types of chemical enhancers, including N-acetyl-L-cysteine (NAC), sodium deoxycholate (SDC), sodium nitroprusside (SNP), reduced glutathione (GSH), glutamine (Gln), chitosan (CS), L-arginine (Arg), 1-dodecylazacycloheptan-2-one (Azone), and soybean lecithin (SPC) (50 and 10 μg/mL respectively). Permeability studies were performed to determine the enhancing effects of these compounds on insulin permeation across the cell-culture model. The enhancing effects of the enhancers were assessed by calculating the apparent permeability coefficients and enhancement ratio. Cytotoxicity of the permeation enhancers at different concentrations was investigated by using the methylthiazolydiphenyl-tetrazolium bromide (MTT) assay. Results showed that 50 μg/mL of NAC, SDC, GSH, CS, Arg, Azone, SPC, SNP, and 10 μg/mL of SNP had a significant enhancing effect on promoting the transport of insulin across the TR146 cell model. MTT assays showed that 50 μg/mL of Gln, Azone, SDC, SNP, Arg, 10 μg/mL SDC, and Arg had obvious toxic effects on TR146 cells. Therefore, NAC, GSH, CS, SPC, and SNP appear to be safe, effective permeability enhancers that promote the transport of insulin across the TR146 cell-culture model of buccal epithelium and may be potential enhancers for buccal delivery of insulin with both low toxicity and high efficiency. [ABSTRACT FROM AUTHOR]

Objective: The purpose of the present study was to investigate the effects of the combination of aspirin, simvastatin in diabetic rat on platelet function., Methods: Eight-week-old male Wistar rats were selected and randomly divided into diabetic group ( n =48) and normal control group ( n =48). Diabetic rats were injected with 1% STZ (65mg/kg, dissolved in 0.l mmol/L, pH 4.5 citrate buffer) to induce diabetic model and the rats in normal control group were injected with the same dose of citrate buffer. A rat with blood glucose greater than 16.8 mmol/L and along with diabetic symptoms of polydipsia, polyuria and weight loss was considered the successful model of diabetes. Diabetic rats and normal Wistar rats were randomly divided into 4 groups and given aspirin(10 mg/kg), simvastatin(2 mg/kg), combination of aspirin(10mg/kg) and simvastatin(2 mg/kg), PBS for 8 weeks, respectively. The platelet function and the expression of CD62P were evaluated. The levels of nitric oxide (NO), endothelin (ET), thromboxane B2(TXB2), prostacyclin (PGI2), adiponectin (APN), TXB2 were detected in the serum. The expressions of heme oxygenase-1(HO-1), HO-2, endothelial nitric oxide synthase(e-NOS), p-eNOS, B-cell lymphoma-2(Bcl-2), cyclooxygenase-2(COX-2) in thoracic aorta were evaluated by Western blot., Results: Compared with control rats, diabetic rats had high platelet aggregation and activation ( P <0.05), which treated aspirin also showed lower aspirin sensitivity ( P <0.05). The combination of drugs upregulated the expression of HO-1, eNOS, p-eNOS, BCL-2, APN levels and decreased the expression of COX-2, and had a greater inhibitory effect on platelet aggregation and activation. The combination of drugs improved endothelial function, adjusted TXA2/PGI2 levels and increased NO levels, which resulted in a great potential antiplatelet effect., Conclusions: These results suggest that simvastatin may improvethe effect of aspirin on anti-platelet function in diabetic rats.

Four dicoumarols (DC, 2-PyDC, 3-PyDC and 4-PyDC) were synthesized and characterized via IR, (1)H NMR, HRMS, and single crystal X-ray crystallography. Two classical intramolecular O-H···O hydrogen bonds (HBs) stabilized their structures. The total HB energies in DC, 2-PyDC, 3-PyDC and 4-PyDC were calculated with the density functional theory (DFT) [B3LYP/6-31G*] method. The in vitro antibacterial activity of DC, 2-PyDC, 3-PyDC and 4-PyDC against Staphylococcus aureus (S. aureus ATCC 29213), methicillin-resistant S. aureus (MRSA XJ 75302), vancomycin-intermediate S. aureus (Mu50 ATCC 700699), and USA 300 (Los Angeles County clone, LAC) was evaluated by observing the minimum inhibitory concentration and time-kill curves. The results showed that among all the compounds, 2-PyDC exhibited the most potent antibacterial activity.

Objective: To investigate the central auditory processing function in children with functional articulation disorders (FAD), and possible causes of FAD., Methods: Twenty-seven children with FAD were selected as the case group and 50 age-matched normal children were selected as the control group. The two groups were compared with respect to the following factors: percentage of individuals with a positive history of language development disorder, and the form, peak latency and peak amplitude of mismatch negativity (MMN) on auditory event-related potentials., Results: Compared with the control group, the case group had a significantly higher percentage of individuals with a positive history of language development disorder (70% vs 8%; P<0.01), a significantly prolonged peak latency of MMN (209 ± 31 ms vs 175 ± 32 ms; P<0.01), and an insignificantly lower peak amplitude of MMN (P>0.05)., Conclusions: Prolonged central auditory processing may be one of the causes of FAD in children.

Aim: To investigate the oxacillin susceptibility restoration of methicillin-resistant Staphylococcus aureus (MRSA) by targeting the signaling pathway of blaR1- blaZ with a DNAzyme., Methods: A DNAzyme (named PS-DRz602) targeting blaR1 mRNA was designed and synthesized. After DRz602 was introduced into a MRSA strain WHO-2, the colony-forming units of WHO-2 on the Mueller-Hinton agar containing 6 mg/L oxacillin and the minimum inhibitory concentrations of oxacillin were determined. The inhibitory effects of DRz602 on the expressions of antibiotic- resistant gene blaR1 and its downstream gene blaZ were detected by real time RT-PCR., Results: PS-DRz602 significantly decreased the transcription of blaR1 mRNA and led to the significant reduction of blaZ in a concentration-dependent manner. Consequently, the resistance of S aureus WHO-2 to the beta-lactam antibiotic oxacillin was significantly inhibited., Conclusion: Our results indicated that blocking the blaR1-blaZ signaling pathway via DNAzyme might provide a viable strategy for inhibiting the resistance of MRSA to beta-lactam antibiotics and that BlaR1 might be a potential target for pharmacological agents combating MRSA.