BackgroundQuercetin is the most abundant flavonoid in fruit and vegetables and is believed to attenuate cardiovascular disease. We hypothesized that quercetin inhibits cardiac hypertrophy by blocking AP-1 (c-fos, c-jun) and activating PPAR-γ signaling pathways.Methodology/Principal FindingsThe aim of this study was to identify the mechanism underlying quercetin-mediated attenuation of cardiac hypertrophy. Quercetin therapy reduced blood pressure and markedly reduced the ratio of left ventricular to body weight (LVW/BW) (P<0.05, vs. spontaneously hypertensive rats (SHRs)). In vitro, quercetin also significantly attenuated Ang II-induced H9C2 cells hypertrophy, as indicated by its concentration dependent inhibitory effects on [3H]leucine incorporation into H9C2 cells (64% reduction) and by the reduced hypertrophic surface area in H9C2 cells compared with the Ang II group (P<0.01, vs. Ang II group). Concurrently, we found that PPAR-γ activity was significantly increased in the quercetin-treated group both in vivo and in vitro when analyzed using immunofluorescent or immunohistochemical assays (P<0.05, vs. SHRs or P<0.01, vs. the Ang II group). Conversely, in vivo, AP-1 (c-fos, s-jun) activation was suppressed in the quercetin-treated group, as was the downstream hypertrophy gene, including mRNA levels of ANP and BNP (P<0.05, vs. SHRs). Additionally, both western blotting and real time-PCR demonstrated that PPAR-γ protein and mRNA were increased in the myocardium and AP-1 protein and mRNA were significantly decreased in the quercetin-treated group (P<0.05, vs. SHRs). Furthermore, western blotting and real time-PCR analyses also showed that transfection with PPAR-γ siRNA significantly increased AP-1 signaling and reversed the effects of quercetin inhibition on mRNA expression levels of genes such as ANP and BNP in hypertrophic H9C2 cells.ConclusionsOur data indicate that quercetin may inhibit cardiac hypertrophy by enhancing PPAR-γ expression and by suppressing the AP-1 signaling pathway.

Objective Empirical evidence on the availability bias associated with diagnostic errors is still insufficient. We investigated whether or not recent experience with clinical problems can lead physicians to make diagnostic errors due to availability bias and whether or not reflection counteracts this bias. Methods Forty-six internal medicine residents were randomly divided into a control group (CG) and experimental group (EG). Among the eight clinical cases used in this study, three experimental cases were similar to the disease of dengue fever (DF) but exhibited different diagnoses, one was actually DF, and the other four filler cases were not associated with DF. First, only the EG received information on DF, while the CG knew nothing about this study. Then, six hours later, all participants were asked to diagnose eight clinical cases via nonanalytic reasoning. Finally, four cases were diagnosed again via reflective reasoning. Results In stage 2, the average score of the CG in the diagnosis of experimental cases was significantly higher than that of the filler cases (0.80 vs. 0.59, p<0.01), but the EG's average score in the two types of cases was not significantly different (0.66 vs. 0.64, p=0.756). The EG and CG had significantly different scores for each experimental case, while no difference was observed in the filler cases. The proportion of diseases incorrectly diagnosed as DF among experimental cases ranged from 71% to 100% in the EG. There were no significant differences between the mean diagnostic accuracy scores obtained by nonanalytic reasoning and those obtained by the reflective reasoning in any cases. Conclusion Availability bias led to diagnostic errors. Misdiagnoses cannot always be repaired solely by adopting a reflective approach.