ABSTRACT
For the last decade, porcine epidemic diarrhea virus (PEDV) variant strains have caused severe damage to the global pig industry. Until now, no effective antivirals have been developed for the therapeutic treatment of PEDV infection. In the present study, we found that quercetin significantly suppressed PEDV infection at noncytotoxic concentrations. A molecular docking study indicated that quercetin might bind the active site and binding pocket of PEDV 3C-like protease (3CLpro). Surface plasmon resonance (SPR) analysis revealed that quercetin exhibited a binding affinity to PEDV 3CLpro. Based on the results of the fluorescence resonance energy transfer (FRET) assay, quercetin was proven to exert an inhibitory effect on PEDV 3CLpro. Since coronavirus 3CLpro is an important drug target and participates in the viral replication process, quercetin should be developed as a novel drug in the control of PEDV infection.
ABSTRACT
Background: High-flow nasal cannula (HFNC) oxygen therapy provides effective respiratory support in patients with hypoxemic respiratory failure. However, the efficacy of HFNC for patients with COVID-19 has not been established. This study was performed to assess the efficacy of HFNC for patients with COVID-19 and describe early predictors of HFNC treatment success in order to develop a prediction tool that accurately identifies the need for invasive mechanical ventilation (IMV). Methods: We retrospectively reviewed the records of patients with COVID-19 who underwent HFNC in 2 hospitals in Wuhan between 1 January and 1 March 2020. Overall survival, the success rate of HFNC treatment and respiratory variables to predict the outcome of HFNC treatment were evaluated.Results: A total of 105 patients were analyzed. Of these, 65 patients (61.9%) showed improved oxygenation and were successfully withdrawn from HFNC. The oxygenation index (PaO2/FiO2), Oxygen saturation index (SpO2/FiO2) and respiratory rate-oxygenation index (ROX index: SpO2/FiO2*RR) at 6h, 12h and 24h of HFNC initiation were closely related to the prognosis. The best predictor was the ROX index at 24h after initiating HFNC (area under the receiver operating characteristic curve, 0.874). In the multivariate logistic regression analysis, young age, gender of female, and lower SOFA score all have predictive value, while a ROX index greater than 6.10 at 24 h after initiation was significantly associated with HFNC success (OR, 104.212; 95% CI, 11.399-952.757; p＜0.001).Conclusions: Our study indicated that HFNC was an effective way of respiratory support in the treatment of severe COVID-19. The ROX index greater than 6.10 at 24 h after initiating HFNC was a good predictor of successful HFNC treatment.