Evaluation of two different domestic colloidal gold assay kit fornew coronavirus antibody in low endemic areas

This study aimed to evaluate the application and diagnostic efficacy of two different colloidal gold kits for the detection of 2019-nCoV immunoglobulin M antibody (anti-IgM) and immunoglobulin G antibody (anti-IgG) in Beijing, a low endemic area, and to guide the rational clinical application. The sera of 29 patients with confirmed novel coronavirus pneumonia (COVID-19) and 19 411 patients from the non-infected screening population were selected to evaluate the sensitivity, specificity and false-positive rate of the 2019-nCoV antibody test kits from Zhuhai Lizhu and Tangshan Innotek using colloidal gold immunochromatography. The sensitivity of Inotec 2019-nCoV was slightly higher than that of Lizhu 2019-nCoV, with a sensitivity of 58.62% and 55.17%, respectively;the specimen collection time of the all-negative group was significantly less than that of the antibody-positive group (P < 0.05);the false-positive rate of the two reagents in the low-prevalence area was 0.16%, and the false-positive rate of 2019-nCoV IgG was higher in Inotec than in Lizhu. The false positive rate for 2019-nCoV IgM was significantly higher than that for IgG for the same brand (Inotec ?2=14.756 09, P=0.000 0;Lizhu ?2=27.492 62, P=0.000). Conclusion The 2019-nCoV antibody test is rapid, simple and easy to perform, with high specificity, and can be used as a rapid screening indicator for new crowns;the specificity, correctness and negative predictive value of the two kits are good, and the application of the other kit for retesting when a positive result occurs can reduce the false positive rate of informing the clinic;the application and analysis of positive reports of new crown antibodies should be combined with the endemic area and clinical comprehensive judgment.

Analysis of Continuous Mutation and Evolution on Circulating SARS-CoV-2

Monitoring the mutation and evolution of the virus is important for tracing its ongoing transmission and facilitating effective vaccine development. A total of 342 complete genomic sequences of SARS-CoV-2 were analyzed in this study. Compared to the reference genome reported in December 2019, 465 mutations were found, among which, 347 occurred in only 1 sequence, while 26 occurred in more than 5 sequences. For these 26 further identified as SNPs, 14 were closely linked and were grouped into 5 profiles. Phylogenetic analysis revealed the sequences formed 2 major groups. Most of the sequences in late period (March and April) constituted the Cluster II, while the sequences before March in this study and the reported S/L and A/B/C types in previous studies were all in Cluster I. The distributions of some mutations were specific geographically or temporally, the potential effect of which on the transmission and pathogenicity of SARS-CoV-2 deserves further evaluation and monitoring. Two mutations were found in the receptor-binding domain (RBD) but outside the receptor-binding motif (RBM), indicating that mutations may only have marginal biological effects but merit further attention. The observed novel sequence divergence is of great significance to the study of the transmission, pathogenicity, and development of an effective vaccine for SARS-CoV-2.

The spatiotemporal trend of renal involvement in COVID-19: A pooled analysis of 17 134 patients.

BACKGROUND: The spatiotemporal trend of renal involvement in coronavirus disease 2019 (COVID-19) patients is still unclear. Therefore, the aim of this study was to reveal the dynamics of renal involvement superimposed COVID-19 according to time and space. METHODS: COVID-19 patients reporting renal involvement were included in this study. The following information was collected from relevant articles: first author, patient demographics, patient enrollment period, location, definition of acute kidney injury (AKI), prevalence of AKI, and use of renal replacement therapy (RRT). RESULTS: A total of 17 134 patients were finally included. The overall prevalence of AKI in COVID-19 patients was 19%, with 7% of them undergoing RRT. The overall risk of AKI in patients enrolled before March 1, 2020 (9%) was significantly lower than that after March 1, 2020 (36%) (P < 0.00001). Moreover, the overall risk of AKI outside Asia (35%) was significantly higher than that in Asia (10%) (P < 0.00001). Additionally, similar to patients requiring RRT, AKI patients were more likely to become seriously ill or even to die (P < 0.00001). CONCLUSIONS: This study found that renal involvement superimposed COVID-19, a comorbidity portending a poor prognosis, has become an increasingly serious problem over time and is more common outside Asia. Thus, more attention should be paid to the management of this specific group of patients.

Differentiation between COVID‐19 and bacterial pneumonia using radiomics of chest computed tomography and clinical features

To develop and validate an effective model for distinguishing COVID‐19 from bacterial pneumonia. In the training group and internal validation group, all patients were randomly divided into a training group (n = 245) and a validation group (n = 105). The whole lung lesion on chest computed tomography (CT) was drawn as the region of interest (ROI) for each patient. Both feature selection and model construction were first performed in the training set and then further tested in the validation set with the same thresholds. Additional tests were conducted on an external multicentre cohort with 105 subjects. The diagnostic model of LightGBM showed the best performance, achieving a sensitivity of 0.941, specificity of 0.981, accuracy of 0.962 on the validation dataset. In this study, we established a differential model to distinguish between COVID‐19 and bacterial pneumonia based on chest CT radiomics and clinical indexes.

Potential effects of SARS-CoV-2 on the gastrointestinal tract and liver.

COVID-19 is a pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Early reported symptoms include fever, cough, and respiratory symptoms. There were few reports of digestive symptoms. However, with COVID-19 spreading worldwide, symptoms such as vomiting, diarrhoea, and abdominal pain have gained increasing attention. Research has found that angiotensin-converting enzyme 2 (ACE2), the SARS-CoV-2 receptor, is strongly expressed in the gastrointestinal tract and liver. Whether theoretically or clinically, many studies have suggested a close connection between COVID-19 and the digestive system. In this review, we summarize the digestive symptoms reported in existing research, discuss the impact of SARS-CoV-2 on the gastrointestinal tract and liver, and determine the possible mechanisms and aetiology, such as cytokine storm. In-depth exploration of the relationship between COVID-19 and the digestive system is urgently needed.

Screening research of anti-SARS-CoV-2 peptides from Mizuhopecten yessoensis based on molecular docking

In order to screen bioactive peptides against SARS-CoV-2 from food raw materials, Mizuhopecten yessoensis myosin was selected as the target sequence, which was enzymatically digested in silico, and then the toxicity and bioactivity of the peptides were predicted. The non-toxicity peptides with activity scores exceeding 0.5 were selected, and SARS-CoV-S/ACE2 complex protein and COVID-19 Mpro hydrolase were selected as targets for molecular docking to identify their viral resistance. The molecular docking results showed that the peptide CSNAIPEL could bind to the two key amino acids GLN42 and GLU329 on the SARS-CoV-S/ACE2 complex protein, and the LibDock Score was 136.03. LPIY could not only combine with ASP38 and TYR491 on the SARS-CoV-S/ACE2 complex protein, but also potentially combine with THR24, THR25 and THR26 on COVID-19 Mpro, and the LibDock Score was 142.85 and 168.04 respectively. QRPR combined with THR24, THR25 and THR26 on the COVID-19 Mpro hydrolase crystal, and the LibDock Score was 154.93. In summary, peptides CSNAIPEL, LPIY and QRPR exhibited well anti-SARS-CoV-2 capability. This study could provide novel ideas for the development of new function foods of anti-SARS-CoV-2 in the future.

A general onepot-method for nucleic acid detection with CRISPR-Cas12a (preprint)

CRISPR/Cas12a system has been shown promising for nucleic acid diagnostics due to its rapid, portable and accurate features. In combination with isothermal amplification technology, single-copy sensitivity can be achieved. However, cleavage of the amplicons and primers by the cis- and trans-activity of Cas12a hinders the attempts to integrate the amplification and detection steps into a single reaction. Through phosphorothioate modification of primer and design of crRNA that allow for the cutting site locating at the modified site of the primer, we realized onepot detection of SARS-CoV-2 with single-copy sensitivity. We also identified the activated Cas12a has a much higher affinity to C nucleotide-rich reporter than others. By applying such reporters, we significantly reduced the reaction time required for the lateral-flow readout. Furthermore, to improve the specificity of the strip-based assay, we created a novel reporter and, when combined with a customized strip, the unspecific signal could be completely eliminated. This established system termed Targeting DNA by Cas12a-based Eye Sight Testing in Onepot Reaction (TESTOR) was validated using clinical cervical samples for human papillomaviruses (HPVs) detection. Our system represents a general approach to integrating the nucleic acid amplification and detection into a onepot reaction in CRISPR-Cas systems, highlighting its potential as a rapid, portable and accurate detection platform of nucleic acids.

Potential Factors for Prediction of Disease Severity of COVID-19 Patients (preprint)

ObjectiveCoronavirus disease 2019 (COVID-19) is an escalating global epidemic caused by SARS-CoV-2, with a high mortality in critical patients. Effective indicators for predicting disease severity in SARS-CoV-2 infected patients are urgently needed. MethodsIn this study, 43 COVID-19 patients admitted in Chongqing Public Health Medical Center were involved. Demographic data, clinical features, and laboratory examinations were obtained through electronic medical records. Peripheral blood specimens were collected from COVID-19 patients and examined for lymphocyte subsets and cytokine profiles by flow cytometry. Potential contributing factors for prediction of disease severity were further analyzed. ResultsA total of 43 COVID-19 patients were included in this study, including 29 mild patients and 14 sever patients. Severe patients were significantly older (61.9{+/-}9.4 vs 44.4{+/-}15.9) and had higher incidence in co-infection with bacteria compared to mild group (85.7%vs27.6%). Significantly more severe patients had the clinical symptoms of anhelation (78.6%) and asthma (71.4%). For laboratory examination, 57.1% severe cases showed significant reduction in lymphocyte count. The levels of Interluekin-6 (IL6), IL10, erythrocyte sedimentation rate (ESR) and D-Dimer (D-D) were significantly higher in severe patients than mild patients, while the level of albumin (ALB) was remarkably lower in severe patients. Further analysis demonstrated that ESR, D-D, age, ALB and IL6 were the major contributing factors for distinguishing severe patients from mild patients. Moreover, ESR was identified as the most powerful factor to predict disease progression of COVID-19 patients. ConclusionAge and the levels of ESR, D-D, ALB and IL6 are closely related to the disease severity of COVID-19 patients. ESR can be used as a valuable indicator for distinguishing severe COVID-19 patients in early stage, so as to increase the survival of severe patients.