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Numerous studies have indicated that the expression of matrix metalloproteinase-9 (MMP-9) contributes to the atherosclerotic plaque hemorrhage and rupture. Aspirin, a non-steroidal anti-inflammation drug, has been known for its anti-platelet effect in the prevention of the vascular complications of atherosclerosis. The present study aimed to investigate the pharmacological effects of aspirin on tumor necrosis factor-α (TNF-α)-induced MMP-9 expression and the underlying molecular mechanisms in murine macrophage RAW264.7 cells. Western blot analysis indicated that the protein level of MMP-9 was reduced by aspirin in a dose-dependent manner. In addition, downregulation of MMP-9 mRNA and activity were detected in aspirin-treated cells using quantitative polymerase chain reaction and a gelatin zymography assay separately. It was also observed that aspirin has a suppressive effect on the activation of nuclear factor (NF)-κB and inhibits the phosphorylation of mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinases 1/2, p38 and c-Jun N-terminal kinase. Furthermore, subsequent to inhibition of the MAPK pathway by specific inhibitors (PD98059, SB203580 and SP600125), the expression of MMP-9 was reduced, indicating that the inhibitory effect of aspirin on MMP-9 in TNF-α-treated RAW264.7 cells may be, at least in part, through suppression of NF-κB activation and the MAPK pathway. These findings support the notion that aspirin has therapeutic potential application in the prevention and treatment of atherosclerosis disease. [ABSTRACT FROM AUTHOR]

Tranexamic Acid (TXA) is commonly administered in total knee arthroplasty for reducing blood loss. There has been a growing interest in the topical use of TXA except intravenous use for prevention of bleeding in TKA. The aim of this study was to develop and validate a HPLC-MS method to detect TXA and apply to compare the pharmacokinetic profile of TXA after intravenous (IV) and topical intra-articular (IA) application of TXA at a dose of 20 mg/kg in rabbits. In order to prove intra-articular administration is better than that of intravenous administration from the point of rabbit pharmacokinetic. Two groups of rabbits (n=6/group) respectively received TXA intra-articularly or intravenously. Blood samples were collected at scheduled time. The concentration of TXA in plasma was determined by a validated HPLCMS method. Excellent linearity was found between 0.015 and 70.0μg/ml with a lower limit of quantitation (LLOQ) of 0.015μg/ml (r>0.99); moreover, all the validation data including accuracy and precision (intra- and inter-day) were all within the required limits. The pharmacokinetic parameters in IA and IV group were: Cmax: 30.65±3.31 VS 54.05± 6.21μg/ml (p<0.01); t1/2: 1.26±0.05 VS 0.68±0.13h (p<0.05); AUC0-t: 42.98±7.73 VS 23.39±4.14μg/ml· h (p<0.01), time above the minimum effective concentration (%T > MEC): 1.5-2.2 VS 0.7-1.2h (p<0.05). HPLC-MS method is suitable for TXA pharmacokinetic studies. The results demonstrated that topical intra-articular application of TXA showed a reduced peak plasma concentration and prolonged therapeutic drug level compared with intravenous TXA from the point of rabbit pharmacokinetic. [ABSTRACT FROM AUTHOR]

Aim: To investigate the mechanism of the interaction between montmorillonite and bacteria by studying the reactions of different charges of montmorillonites with bacteria., Methods: Bacteriostatic test: one loop of E. coli and Staphylococcus aureus at the concentration of 1 x 10(6).mL-1 was incubated to the plate culture medium containing different concentrations of montmorillonite, and incubated 24 h to observe the growth of bacteria. Bacterial adsorptive test: different amounts of montmorillonite were added into the artificially simulated intestinal solution (containing bacteria 1 x 10(7).mL-1). After the culture, the bacterial colonies were counted., Results: The results showed that montmorillonite per se showed no bacteriostatic or bactericidal effect, but after exchange with metal ion and functional groups which inhibits bacteria, then it showed these activities. Adsorption was the main way between montmorillonite and bacteria. The special way of fixing bacteria into the "carriage" of montmorillonite gel which carry this structure was its pharmacological basis of curing diarrhea. The adsorption effect was related to layer charge density of the montmorillonites., Conclusion: Montmorillonite showed adsorption ability of bacteria with minus related to its layer charge, but has no bacteriostatic and bactericidal effect.