Background and aim: The role of Helicobacter pylori and aspirin in peptic ulcer formation and recurrence remains an important clinical topic. The interaction between aspirin and H pylori in vitro is also not clear. We investigated the effect of aspirin on the growth of H pylori and on the susceptibility of H pylori to antimicrobials. Methods: Time killing studies of H pylori were performed with different concentrations of aspirin and salicylate. Growth of bacteria was assessed spectrophotometrically and by viable colony count. The effects of aspirin on the efficiency of colony formation and on metronidazole induced mutation to rifampicin resistance in H pylori were determined. Minimal inhibitory concentrations (MICs) of aspirin and metronidazole were tested by the standard agar dilution method. MICs of amoxycillin and clarithromycin were determined by the E test method. Results: Aspirin and salicylate inhibited the growth of H pylori in a dose dependent manner and bactericidal activity was due to cell lysis. Aspirin 400 µg/ml caused a 2 logs decrease in colony forming units/ml at 48 hours, and suppressed the normal ability of metronidazole to induce new mutations to rifampicin. The IC 90 of aspirin was 512 µg/ml. Increased susceptibility of amoxycillin, clarithromycin, and metronidazole to H pylori was observed at 1 mM (180 µg/ml) aspirin. Conclusions: Aspirin inhibited the growth of H pylori, suppressed the mutagenic effect of metronidazole, and enhanced the susceptibility of H pylori to antimicrobial agents. This mechanism is important in future drug development for effective clearing and overcoming resistance.

Objective: The current study aimed to investigate the effect of SNS use on graduate students’ depression and further explored the effect of negative social comparison and an individual’s implicit personality theory. Methods: Scales for Social Networking Site Use Intensity, the Negative Social Comparison Measure, the Implicit Personality Theory Inventory, and CES-D were used to investigate 1792 graduate students from a full-time university in Wuhan. Result: (1) Social networking site use was positively correlated with negative social comparison and depression; (2) the mediating effect of negative social comparison was significant in social networking site use’s influence on depression; (3) after controlling for negative social comparison, graduate students’ use of SNS could negatively predict depression; and (4) the mediation effect of negative social comparison was moderated by an individual’s implicit personality theory. Specifically, the mediation effect was more pronounced among the entity theorists, while the graduate students’ incremental implicit personality theory may buffer the depressive effect of negative social comparison. Conclusions: Negative social comparison mediates the relationship between SNS use and depression; in addition, individual differences in implicit personality theory (the entity theorist vs. incremental theorist) moderate the link between negative social comparison and depression.