The global COVID-19 coronavirus pandemic has infected over 109 million people, leading to over 2 million deaths up to date and still lacking of effective drugs for patient treatment. Here, we screened about 1.8 million small molecules against the main protease (M^pro) and papain like protease (PL^pro), two major proteases in severe acute respiratory syndrome-coronavirus 2 genome, and identified 1851M^pro inhibitors and 205 PL^pro inhibitors with low nmol/l activity of the best hits. Among these inhibitors, eight small molecules showed dual inhibition effects on both M^pro and PL^pro, exhibiting potential as better candidates for COVID-19 treatment. The best inhibitors of each protease were tested in antiviral assay, with over 40% of M^pro inhibitors and over 20% of PL^pro inhibitors showing high potency in viral inhibition with low cytotoxicity. The X-ray crystal structure of SARS-CoV-2 M^pro in complex with its potent inhibitor 4a was determined at 1.8 Å resolution. Together with docking assays, our results provide a comprehensive resource for future research on anti-SARS-CoV-2 drug development.
Humans ; Antiviral Agents/chemistry* ; COVID-19 ; COVID-19 Drug Treatment ; High-Throughput Screening Assays ; Molecular Docking Simulation ; Protease Inhibitors/chemistry* ; SARS-CoV-2/enzymology* ; Viral Nonstructural Proteins

Objective:To investigate the diagnostic and prognostic value of D-dimer level in patients with hepatitis B-related acute-on-chronic liver failure (HBV-ACLF).Methods:A total of 142 cases diagnosed with ACLF were randomly selected as research objects in the open cohort using the Chinese Group on the Study of Severe Hepatitis B-ACLF (COSSH-ACLF). Plasma D-dimer levels were compared between patients with ACLF and non-ACLF and patients with different ACLF grades. Survival and death group D-dimer levels were compared with the end points of 28 days and 90 days, respectively. The correlation between D-dimer and other laboratory indicators and prognostic scores were investigated. Area under receiver operating characteristic curve (AUROC) was used to evaluate the D-dimer value for predicting the prognosis of ACLF patients. 125 external ACLF cases were used for validation. A Student t test or Mann-Whitney U test was used to compare continuous measurement data between two groups. Kruskal-Wallis test was used to compare continuous measurement data between multiple groups.Results:Plasma D-dimer levels in the ACLF [2 588.5 (1 142.8, 5 472.8) μg/L] ] and non-ACLF group [1 385.5 (612.0, 3 840.3) μg/L] had a significant difference ( P<0.001). ACLF-3 patients had significantly higher D-dimer levels than ACLF-1/2 patients (ACLF-3 vs. ACLF-1, P<0.001; ACLF-3 vs. ACLF-2, P<0.05). Patients who died at 28/90 days had significantly higher D-dimer levels than those whom survived ( P<0.001). There was a significant positive correlation between D-dimer level with prothrombin time (PT), international normalized ratio (INR), high-density lipoprotein C, as well as various prognostic scores (COSSH-ACLFs, CLIF-C ACLFs, CLIF-OFs, MELDs). AUROC of D-dimer in predicting the prognosis of ACLF patients at 28 days and 90 days was 0.751 (95% CI: 0.649-0.852) and 0.787 (95% CI: 0.695-0.878), respectively, which did not differ significantly compared with the predictive ability of other scores ( P<0.05), and similar results were confirmed by an external validation group of 125 cases. Conclusion:D-dimer level is significantly higher in patients with ACLF, so it is an independent predictor of prognosis at 28 and 90 days.

Objective:To screen serum protein markers and evaluate their diagnostic application value in hepatitis B-related acute-on-chronic liver failure (HBV-ACLF).Methods:Serum samples of patients with HBV-ACLF, chronic hepatitis B (CHB) and normal healthy volunteers ( n = 5/group) were determined by cytokine antibody chip in line with the Chinese Diagnostic Standards Study for HBV-ACLF (COSSH-ACLF) cohort. The differentially expressed proteins significance were identified by microarray analysis and prediction. The preliminary serological markers of HBV-ACLF were screened for diagnosis. The potential markers were determined by enzyme-linked immunosorbent assay (ELISA), area under the receiver operating characteristic curve (AUROC) analysis and liver tissue immunohistochemistry for the diagnosis of HBV-ACLF. Student t-test or Mann-Whitney U test were used to compare the continuous measurement data between the two groups, and analysis of variance and Kruskal-Wallis test were used to compare the continuous measurement data between multiple groups. Results:Cytokine antibody chip preliminary screening results showed that the expression levels of these six cytokines, namely, macrophage inflammatory protein 3α (MIP-3α), hepatocyte growth factor, E-selectin, osteopontin, growth differentiation factor 15 and carcinoembryonic antigen-related cellular adhesion molecule 1 were significantly increased in the HBV-ACLF group. Among them, the expression level of MIP-3α was significantly higher in the HBV-ACLF group (99.6 times higher than CHB group and 146.9 times higher than healthy volunteers’ group, respectively, P < 0.0001) as validated by serum ELISA in 132 HBV-ACLF cases, 91 CHB cases and 72 healthy volunteers. AUROC analysis showed that the high expression of MIP-3α could be used as a marker to distinguish patients with HBV-ACLF from CHB. The AUROC was 0.995 (95% CI: 0.990 ~ 1.000), with sensitivity and specificity of 95.5% and. 98.9%, respectively. Immunohistochemistry showed that MIP-3α was positively expressed in HBV-ACLF-derived liver tissues, and negatively expressed in CHB-derived liver and normal liver tissues. Conclusion:Serum MIP-3α level is closely related to the pathological characteristics of HBV-ACLF. Therefore, it may be used as a potential serological marker for the diagnosis of HBV-ACLF.

The correct differentiation of oligodendrocyte precursor cells (OPCs) is essential for the myelination and remyelination processes in the central nervous system. Determining the regulatory mechanism is fundamental to the treatment of demyelinating diseases. By analyzing the RNA sequencing data of different neural cells, we found that cyclin-dependent kinase 18 (CDK18) is exclusively expressed in oligodendrocytes. In vivo studies showed that the expression level of CDK18 gradually increased along with myelin formation during development and in the remyelination phase in a lysophosphatidylcholine-induced demyelination model, and was distinctively highly expressed in oligodendrocytes. In vitro overexpression and interference experiments revealed that CDK18 directly promotes the differentiation of OPCs, without affecting their proliferation or apoptosis. Mechanistically, CDK18 activated the RAS/mitogen-activated protein kinase kinase 1/extracellular signal-regulated kinase pathway, thus promoting OPC differentiation. The results of the present study suggest that CDK18 is a promising cell-type specific target to treat demyelinating disease.

Objective To investigate the teaching effects of flipped class model on the Surgery Intensive Care Unit (SICU) nurses' ability of autonomic learning. Methods From July to December 2015, a total of 38 nurses who worked in SICU of Zhejiang Cancer Hospital were selected as the research objects by convenience sampling method. The nurses were trained in postoperative pain management knowledge by flipped class model, and were evaluated before and after the training by rating scale of self-directed learning competence for nurses. Results The total score of rating scale of self-directed learning competence for nurses, self motivation belief, task analysis, self monitoring and regulation, self evaluation were (128.26±18.69), (54.50±7.65), (22.05±3.66), (37.57±5.82) and (14.13±2.67) after the training, which all improved than (108.89±15.71), (47.18±6.61), (18.03±3.33), (31.37±5.24) and (12.32±2.14) respectively before training. The differences were statistically significant (t=-4.889, -4.460, -5.013, -4.883, -3.266; P<0.05). Conclusions Flipped class teaching model improves nurses' autonomous learning ability comprehensively and provide a new teaching mode for nurses' training.

OBJECTIVE:To establish a method for the simultaneous determination of 6 kinds of residual organic solvents in Omeprazole magnesium,such as methanol,isopropanol,acetonitrile,dichloromethane,ethyl acetate and toluenein. METHODS:Headspace GC was adopted. The determination was performed on the column of DB-624 column by temperature programming. The inlet temperature was 200 ℃,and hydrogen flame ionization detector was adopted with the temperature of 250 ℃;nitrogen gas was used as carrier gas with flow rate of 2.0 mL/min;the splitting-radio was 5 : 1,and sample size was 1 mL;the headspace tem-perature was 80 ℃ and the equilibrium time was 20 min. RESULTS:The linear range were 12.56-628.00 μg/mL for methanol(r=0.9997),20.22-1011.20 μg/mL for isopropanol(r=0.9999),1.96-97.76 μg/mL for acetonitrile(r=0.9997),3.10-154.88 μg/mL for dichloromethane(r=0.9998),20.69-1034.56 μg/mL for ethyl acetate(r=0.9998),and 3.53-176.72 μg/mL for toluene(r=0.9998);the limits of quantitation were 1.00,0.91,0.47,0.93,0.41 and 0.35 μg/mL respectively;the limits of detection were 0.31,0.30,0.14,0.31,0.12 and 0.11 μg/mL respectively;RSDs of precision,stability and reproducibility tests were lower than 3%;the recoveries were 94.53%-101.29%(RSD=2.15%,n=9),97.78%-103.42%(RSD=1.77%,n=9),96.99%-105.76%(RSD=2.59%,n=9),96.83%-102.05%(RSD=1.86%,n=9),97.98%-101.13%(RSD=0.88%,n=9)and 97.80%-102.40%(RSD=1.41%,n=9). CONCLUSIONS:The method is sensitive and accurate,can be used for the simultaneous determination of 6 kinds of residual organic solvents in Omeprazole magnesium,such as methanol,isopropanol,acetonitrile,dichloromethane,eth-yl acetate and toluenein.

Objective·To analyze clinical and pathological characteristics of gastric malignancies from a single center of Ruijin Hospital,and provide references for making healthy policy on gastric tumors.Methods·The data sources were from hospital in-patients database including demographic information,family history,clinicopathological information,and census registering information during 2005 to 2014.The demographic data and clinicopathological data were analyzed.Results·The total number was 3 315 cases with gastric malignancies (2 184 male patients and 1 131 female patients).It was about 2 times as high in males as in females.The patient age was between 18 to 98 years old (mean 59.71 years old).Based on pathologic diagnosis,3 122 cases (94.2％) were gastric adenocarcinoma,others were gastrointestinal stromal tumors (5.5％),neuroendocrine tumor (0.2％) and malignant lymphoma (0.1％).Out of patients with gastric carcinoma,about 4.46％ of cases ran in families.Conclusion·Over 94％ cases of gastric malignancies are gastric carcinomas.Specific risk profiles of gastric carcinomas include age,gender and family factors.

Objective:To establish a method for the content determination of magnesium in esomeprazole magnesium. Methods:The content of magnesium in esomeprazole magnesium was determined by inductive coupled plasma atomic emission spectrometry. Re-sults:The linear range was 10.0-80.0 μg·ml-1(r=0.999 8). The average recovery was 99.55% with RSD of 1.35% (n=9). The detection limit was 0. 000 75 μg·ml-1 and the quantitative limit was 0. 002 5 μg·ml-1 . Conclusion:The method is accurate, sensitive and reproducible, which can be used for the content determination of magnesium in esomeprazole magnesium.

Objective: To explore the application of real-time three-dimensional ultrasound in locating the course, the brand and the blind end of internal opening of congenital preauricular fistula. Methods: Congenital preauricular fistula patients from Changhai Hospital were studied. All the cases were evaluated using two-dimensional and three-dimensional ultrasound before surgeries. The surgery findings were utilized as the gold standard. The imaging features of 3D ultrasound were described to determine the accuracy of the blind end location, the course of the main fistula tract and the branch tracts. The diagnosis was compared with the surgery findings. Results: In 89 cases, among which there were 21 branch fistulae. There were 68 bend fistulae without branch. The diagnostic accuracy of both two-dimensional ultrasound and three-dimensional ultrasound was 100%. The accuracy in locating the blind end of internal opening, the course of the branch tracts with 3D ultrasound was 92.1%(82/89), 85.7%(18/21) , compared to 80.9%(72/89), 57.1%(12/21) with 2D ultrasound. It was obvious that 3D ultrasound had more advantages. These differences were statistically significant (χ²=4.8, P<0.05; χ²=4.2, P<0.05). Conclusions Compared with 2D ultrasound, 3D ultrasound can accurately locate the blind end of internal opening, the course, and the branch of preauricular fistula, clearly display the morphology and the spatial structure of preauricular fistulaand its surroundings. It has high clinical application value in preoperative imaging examination.

Objective:To establish a headspace capillary gas chromatography method for the determination of residual solvents in erlotinib hydrochloride .Methods:A DB-624 capillary column (30 m ×0.53 mm, 3.0 μm) was used and the carrier gas was nitro-gen.The flow rate was 2.0 ml· min-1 and the inlet temperature was 190℃.The FID detector temperature was 230 ℃.The column temperature program was with the initial temperature of 35℃( maitaining 8 min) , risen to 170℃with the rate of 28℃· min-1 ( main-taining 8 min) , and then risen to 200℃with the rate of 32℃· min-1 ( maintaining 7 min) .The headspace vial temperature was 100℃and the time was 30 min.Results:Ethanol, isopropanol, methylene chloride and n-butanol had a good linear relationship within the range of 0.68-409.14 μg· ml-1 (r=0.999 8),0.67-404.88 μg· ml-1 (r=0.999 8),1.71-51.31μg· ml-1 (r=0.999 7) and 0.72-431.12 μg· ml-1(r=0.999 8), respectively.The average recovery was 99.0% (RSD=0.41%, n=9), 100.2%(RSD=0.52%, n=9),97.1%(RSD=1.75%, n =9) and 102.5% (RSD=1.08%, n=9), respectively.Conclusion: The method is simple and accurate , which can be used for the determination of four residual organic solvents in erlotinib hydrochloride .