DNA-scaffolded multivalent vaccine against SARS-CoV-2.

Short peptides are poor immunogens. One way to increase their immune responses is by arraying immunogens in multivalency. Simple and efficient scaffolds for spatial controlling the inter-antigen distance and enhancing immune activation are required. Here, we report a molecular vaccine design principle that maximally drives potent SARS-CoV-2 RBD subunit vaccine on DNA duplex to induce robust and efficacious immune responses in vivo. We expect that the DNA-peptide epitope platform represents a facile and generalizable strategy to enhance the immune response. STATEMENT OF SIGNIFICANCE: DNA scaffolds offer a biocompatible and convenient platform for arraying immunogens in multivalency antigenic peptides, and spatially control the inter-antigen distance. This can effectively enhance immune response. Peptide (instead of entire protein) vaccines are highly attractive. However, short peptides are poor immunogens. Our DNA scaffolded multivalent peptide immunogen system induced robust and efficacious immune response in vivo as demonstrated by the antigenic peptide against SARS-CoV-2. The present strategy could be readily generalized and adapted to prepare multivalent vaccines against other viruses or disease. Particularly, the different antigens could be integrated into one single vaccine and lead to super-vaccines that can protect the host from multiple different viruses or multiple variants of the same virus.

Label-free impedimetric immunosensor for point-of-care detection of COVID-19 antibodies.

The COVID-19 pandemic has posed enormous challenges for existing diagnostic tools to detect and monitor pathogens. Therefore, there is a need to develop point-of-care (POC) devices to perform fast, accurate, and accessible diagnostic methods to detect infections and monitor immune responses. Devices most amenable to miniaturization and suitable for POC applications are biosensors based on electrochemical detection. We have developed an impedimetric immunosensor based on an interdigitated microelectrode array (IMA) to detect and monitor SARS-CoV-2 antibodies in human serum. Conjugation chemistry was applied to functionalize and covalently immobilize the spike protein (S-protein) of SARS-CoV-2 on the surface of the IMA to serve as the recognition layer and specifically bind anti-spike antibodies. Antibodies bound to the S-proteins in the recognition layer result in an increase in capacitance and a consequent change in the impedance of the system. The impedimetric immunosensor is label-free and uses non-Faradaic impedance with low nonperturbing AC voltage for detection. The sensitivity of a capacitive immunosensor can be enhanced by simply tuning the ionic strength of the sample solution. The device exhibits an LOD of 0.4 BAU/ml, as determined from the standard curve using WHO IS for anti-SARS-CoV-2 immunoglobulins; this LOD is similar to the corresponding LODs reported for all validated and established commercial assays, which range from 0.41 to 4.81 BAU/ml. The proof-of-concept biosensor has been demonstrated to detect anti-spike antibodies in sera from patients infected with COVID-19 within 1 h. Photolithographically microfabricated interdigitated microelectrode array sensor chips & label-free impedimetric detection of COVID-19 antibody.

Additive-controlled asymmetric iodocyclization enables enantioselective access to both α- and ß-nucleosides.

ß-Nucleosides and their analogs are dominant clinically-used antiviral and antitumor drugs. α-Nucleosides, the anomers of ß-nucleosides, exist in nature and have significant potential as drugs or drug carriers. Currently, the most widely used methods for synthesizing ß- and α-nucleosides are via N-glycosylation and pentose aminooxazoline, respectively. However, the stereoselectivities of both methods highly depend on the assisting group at the C2' position. Herein, we report an additive-controlled stereodivergent iodocyclization method for the selective synthesis of α- or ß-nucleosides. The stereoselectivity at the anomeric carbon is controlled by the additive (NaI for ß-nucleosides; PPh3S for α-nucleosides). A series of ß- and α-nucleosides are prepared in high yields (up to 95%) and stereoselectivities (ß:α up to 66:1, α:ß up to 70:1). Notably, the introduced iodine at the C2' position of the nucleoside is readily functionalized, leading to multiple structurally diverse nucleoside analogs, including stavudine, an FDA-approved anti-HIV agent, and molnupiravir, an FDA-approved anti-SARS-CoV-2 agent.

Label-free impedimetric immunosensor for point-of-care detection of COVID-19 antibodies

The COVID-19 pandemic has posed enormous challenges for existing diagnostic tools to detect and monitor pathogens. Therefore, there is a need to develop point-of-care (POC) devices to perform fast, accurate, and accessible diagnostic methods to detect infections and monitor immune responses. Devices most amenable to miniaturization and suitable for POC applications are biosensors based on electrochemical detection. We have developed an impedimetric immunosensor based on an interdigitated microelectrode array (IMA) to detect and monitor SARS-CoV-2 antibodies in human serum. Conjugation chemistry was applied to functionalize and covalently immobilize the spike protein (S-protein) of SARS-CoV-2 on the surface of the IMA to serve as the recognition layer and specifically bind anti-spike antibodies. Antibodies bound to the S-proteins in the recognition layer result in an increase in capacitance and a consequent change in the impedance of the system. The impedimetric immunosensor is label-free and uses non-Faradaic impedance with low nonperturbing AC voltage for detection. The sensitivity of a capacitive immunosensor can be enhanced by simply tuning the ionic strength of the sample solution. The device exhibits an LOD of 0.4 BAU/ml, as determined from the standard curve using WHO IS for anti-SARS-CoV-2 immunoglobulins;this LOD is similar to the corresponding LODs reported for all validated and established commercial assays, which range from 0.41 to 4.81 BAU/ml. The proof-of-concept biosensor has been demonstrated to detect anti-spike antibodies in sera from patients infected with COVID-19 within 1 h. Photolithographically microfabricated interdigitated microelectrode array sensor chips & label-free impedimetric detection of COVID-19 antibody.

Experience of using a smartphone WeChat applet for dental anxiety assessment and preoperative evaluation: A nationwide multicenter study

Introduction Dental anxiety is a multivariate phenomenon that regularly occurs during a dental procedure. Although it may lead to patients' safety concerns and adverse events in routine treatment, it is often ignored. The purpose of this research is to develop a novel WeChat Applet for dental anxiety (WADA) with the following features and aims: (1) to help patients with dental anxiety management;(2) provide patient with a physical status self-evaluation;and(3) provide a platform for online assessment and tele-consultancy by dentists. We aimed to test and verify whether such an applet could play a beneficial role before and after a dental procedure and facilitate management of high-risk patients during the COVID-19 pandemic. Materials and methods During the 12-month survey period (August 2020 to July 2021), a total of 180 patients aged 3–74 years from eight different cities (n = 180 at the end of treatment, n = 25 for the System Usability Scale (SUS) and follow-up interview) and 20 medical staff from eight different cities (n =20 for follow-up interview) were evaluated by WADA. At the end of the survey period, the results of the interviews were analyzed thematically. Results WADA assessment results from 180 patients and follow-up interview results from 45 participants were analyzed. In this study with a male to female ratio of 2:3, 75% were found to be suffering from dental anxiety, 86% were found with postoperative complications, and 11 cases were found to have contraindications to surgery. The total SUS score for WADA is 72.25 above the mean score, proving that WADA is a relevant and useful tool before and after dental treatment. Based on the results of the interviews, the following themes were identified: patient satisfaction;dentists' effectiveness;multi-center data integration;and increase its frequency of usage. Conclusions The WADA was developed for dental procedures and is effective for reducing treatment risks, improving patients' satisfaction and dentists' convenience, especially in terms of facilitating management of high-risk patient during the COVID-19 pandemic.

A gold nanoparticle-protein G electrochemical affinity biosensor for the detection of SARS-CoV-2 antibodies: a surface modification approach.

As COVID-19 waves continue to spread worldwide, demand for a portable, inexpensive and convenient biosensor to determine community immune/infection status is increasing. Here we describe an impedance-based affinity biosensor using Interdigitated Electrode (IDE) arrays to detect antibodies to SARS-CoV-2 in serum. We created the biosensor by functionalizing the IDEs' surface with abaculaovirus-expressed and purified Spike (S) protein to bind anti-SARS CoV-2antibodies. Gold nanoparticles (GNP) fused to protein G were used to probe for bound antibodies. An ELISA assay using horseradish peroxidase-protein G to probe for bound IgG confirmed that the purified S protein bound a commercial source of anti-SARS-CoV-2 antibodies specifically and bound anti-SARS-CoV-2 antibodies in COVID-19 positive serum. Then we demonstrated that our biosensor could detect anti-SARS-CoV-2 antibodies with 72% sensitivity in 2 h. Using GNP-protein G, the affinity biosensor had increased impedance changes with COVID-19positive serum and minimal or decreased impedance changes with negative serum. This demonstrated that our biosensor could discriminate between COVID-19 positive and negative sera, which were further improved using poly(vinyl alcohol)as a blocking agent.

Improving immunoassay detection accuracy of anti-SARS-CoV-2 antibodies through dual modality validation.

A novel test strategy is proposed with dual-modality detection techniques for COVID-19 antibody detection. The full-length S protein of SARS-CoV-2 was chemically immobilized on a glass surface to capture anti-SARS-CoV-2 IgG in patient serum and was detected through either Electrochemical Impedance Spectroscopy (EIS) or fluorescence imaging with labeled secondary antibodies. Gold nanoparticles conjugated with protein G were used as the probe and the bound GNP-G was detected through EIS measurements. Anti-human-IgG conjugated with the fluorescent tag Alexa Fluor 488 was used as the probe for fluorescence imaging. Clinical SARS-CoV-2 IgG positive serum and negative controls were used to validate both modalities. For fluorescence-based detection, a high sensitivity was noticed with a quantification range of 0.01-0.1 A.U.C. and a LOD of 0.004 A.U.C. This study demonstrates the possibility of utilizing different measurement techniques in conjunction for improved COVID-19 serology testing.

An impedimetric biosensor for COVID-19 serology test and modification of sensor performance via dielectrophoresis force.

Coronavirus disease 2019 (COVID-19) has caused significant global morbidity and mortality. The serology test that detects antibodies against the disease causative agent, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has often neglected value in supporting immunization policies and therapeutic decision-making. The ELISA-based antibody test is time-consuming and bulky. This work described a gold micro-interdigitated electrodes (IDE) biosensor for COVID antibody detection based on Electrochemical Impedance Spectroscopy (EIS) responses. The IDE architecture allows easy surface modification with the viral structure protein, Spike (S) protein, in the gap of the electrode digits to selectively capture anti-S antibodies in buffer solutions or human sera. Two strategies were employed to resolve the low sensitivity issue of non-faradic impedimetric sensors and the sensor fouling phenomenon when using the serum. One uses secondary antibody-gold nanoparticle (AuNP) conjugates to further distinguish anti-S antibodies from the non-specific binding and obtain a more significant impedance change. The second strategy consists of increasing the concentration of target antibodies in the gap of IDEs by inducing an AC electrokinetic effect such as dielectrophoresis (DEP). AuNP and DEP methods reached a limit of detection of 200 ng/mL and 2 µg/mL, respectively using purified antibodies in buffer, while the DEP method achieved a faster testing time of only 30 min. Both strategies could qualitatively distinguish COVID-19 antibody-positive and -negative sera. Our work, especially the impedimetric detection of COVID-19 antibodies under the assistance of the DEP force presents a promising path toward rapid, point-of-care solutions for COVID-19 serology tests.

Management strategies and outcomes of acute coronary syndrome (ACS) during Covid-19 pandemic.

BACKGROUND: The COVID-19 outbreak represents a significant challenge to international health. Several studies have reported a substantial decrease in the number of patients attending emergency departments with acute coronary syndromes (ACS) and there has been a concomitant rise in early mortality or complications during the COVID-19 pandemic. A modified management system that emphasizes nearby treatment, safety, and protection, alongside a closer and more effective multiple discipline collaborative team was developed by our Chest Pain Center at an early stage of the pandemic. It was therefore necessary to evaluate whether the newly adopted management strategies improved the clinical outcomes of ACS patients in the early stages of the COVID-19 pandemic. METHODS: Patients admitted to our Chest Pain Center from January 25th to April 30th, 2020 based on electronic data in the hospitals ACS registry, were included in the COVID-19 group. Patients admitted during the same period (25 January to 30 April) in 2019 were included in the pre-COVID-19 group. The characteristics and clinical outcomes of the ACS patients in the COVID-19 period group were compared with those of the ACS patients in the pre-COVID-19 group. Multivariate logistic regression analyses were used to identify the risk factors associated with clinical outcomes. RESULTS: The number of patients presenting to the Chest Pain Center was reduced by 45% (p = 0.01) in the COVID-19 group, a total of 223 ACS patients were included in the analysis. There was a longer average delay from the onset of symptom to first medical contact (FMC) (1176.9 min vs. 625.2 min, p = 0.001) in the COVID-19 period group compared to the pre-COVID-19 group. Moreover, immediate percutaneous coronary intervention (PCI) (80.1% vs. 92.3%, p = 0.008) was performed less frequently on ACS patients in the COVID-19 group compared to the pre-COVID-19 group. However, more ACS patients received thrombolytic therapy (5.8% vs. 0.6%, p = 0.0052) in the COVID-19 group than observed in the pre-COVID-19 group. Interestingly, clinical outcome did not worsen in the COVID-19 group when cardiogenic shock, sustained ventricular tachycardia, ventricular fibrillation or use of mechanical circulatory support (MCS) were compared against the pre-COVID-19 group (13.5% vs. 11.6%, p = 0.55). Only age was independently associated with composite clinical outcomes (HR = 1.3; 95% CI 1.12-1.50, p = 0.003). CONCLUSION: This retrospective study showed that the adverse outcomes were not different during the COVID-19 pandemic compared to historical control data, suggesting that newly adopted management strategies might provide optimal care for ACS patients. Larger sample sizes and longer follow-up periods on this issue are needed in the future.

Aspulvins A-H, Aspulvinone Analogues with SARS-CoV-2 Mpro Inhibitory and Anti-inflammatory Activities from an Endophytic Cladosporium sp.

Eight new aspulvinone analogues, aspulvins A-H (1-8) and aspulvinones D, M, O, and R (9-12), were isolated from cultures of the endophytic fungus Cladosporium sp. 7951. Detailed spectroscopic analyses were conducted to determine the structures of the new compounds. All isolates displayed different degrees of inhibitory activity against the severe acute respiratory syndrome coronavirus 2 main protease (SARS-CoV-2 Mpro) at 10 µM. Notably, compounds 9, 10, and 12 showed potential SARS-CoV-2 Mpro inhibition with IC50 values of 10.3 ± 0.6, 9.4 ± 0.6, and 7.7 ± 0.6 µM, respectively. For all compounds except 3 and 4, the anti-inflammatory activity occurred by inhibiting the release of lactate dehydrogenase (LDH) with IC50 values ranging from 0.7 to 7.4 µM. Compound 10 showed the most potent anti-inflammatory activity by inhibiting Casp-1 cleavage, IL-1ß maturation, NLRP3 inflammasome activation, and pyroptosis. The findings reveal that the aspulvinone analogues 9, 10, and 12 could be promising candidates for coronavirus disease 2019 (COVID-19) treatment as they inhibit SARS-CoV-2 infection and reduce inflammatory reactions caused by SARS-CoV-2.

The effect of previous oral anticoagulant use on clinical outcomes in COVID-19: A systematic review and meta-analysis.

Data on the prognosis of patients treated with oral anticoagulation (OAC) prior to hospital admission for COVID-19 remains controversial and insufficient. Therefore, we endeavored to perform a systematic review and meta-analysis to evaluate the effect of chronic use of OAC prior to the diagnosis of COVID-19 on intensive care unit (ICU) admission and mortality. An electronic search of the Pubmed, Embase, Cochrane library databases was conducted. Meta-analysis and statistical analyses were completed with using the RevMan 5.3 and Stata 12.0. A total of 13 articles representing data from 1,266,231 participants were included in this study. The meta-analysis of unadjusted results showed no decrease in mortality (OR = 1.31, 95% CI: 0.99 to 1.73, P = 0.059) or ICU admission rate (OR = 0.71, 95% CI: 0.29 to 1.77, P = 0.46) in COVID-19 patients with prior OAC therapy at hospital admission compared to patients without prior use of OAC. Moreover, the meta-analysis of adjusted results showed no lower risk of mortality (OR = 1.08, 95% CI: 0.90 to 1.30, P = 0.415) or ICU admission (OR = 1.50, 95% CI: 0.72 to 3.12, P = 0.284) in patients with prior OAC use compared to patients without previous OAC use. In conclusion, the results of this study revealed that the use of OAC prior to hospital admission appeared to be ineffective in reducing the risk of intensive care need and mortality in COVID-19 patients. Randomized controlled trials are needed to evaluate and optimize the use of OAC in COVID-19 infection.

Quantitative CT imaging features for COVID-19 evaluation: The ability to differentiate COVID-19 from non- COVID-19 (highly suspected) pneumonia patients during the epidemic period.

OBJECTIVES: COVID-19 and Non-Covid-19 (NC) Pneumonia encountered high CT imaging overlaps during pandemic. The study aims to evaluate the effectiveness of image-based quantitative CT features in discriminating COVID-19 from NC Pneumonia. MATERIALS AND METHODS: 145 patients with highly suspected COVID-19 were retrospectively enrolled from four centers in Sichuan Province during January 23 to March 23, 2020. 88 cases were confirmed as COVID-19, and 57 patients were NC. The dataset was randomly divided by 3:2 into training and testing sets. The quantitative CT radiomics features were extracted and screened sequentially by correlation analysis, Mann-Whitney U test, the least absolute shrinkage and selection operator (LASSO) logistic regression (LR) and backward stepwise LR with minimum AIC methods. The selected features were used to construct the LR model for differentiating COVID-19 from NC. Meanwhile, the differentiation performance of traditional quantitative CT features such as lesion volume ratio, ground glass opacity (GGO) or consolidation volume ratio were also considered and compared with Radiomics-based method. The receiver operating characteristic curve (ROC) analysis were conducted to evaluate the predicting performance. RESULTS: Compared with traditional CT quantitative features, radiomics features performed best with the highest Area Under Curve (AUC), sensitivity, specificity and accuracy in the training (0.994, 0.942, 1.0 and 0.965) and testing sets (0.977, 0.944, 0.870, 0.915) (Delong test, P < 0.001). Among CT volume-ratio based models using lesion or GGO component ratio, the model combining CT lesion score and component ratio performed better than others, with the AUC, sensitivity, specificity and accuracy of 0.84, 0.692, 0.853, 0.756 in the training set and 0.779, 0.667, 0.826, 0.729 in the testing set. The significant difference of the most selected wavelet transformed radiomics features between COVID-19 and NC might well reflect the CT signs. CONCLUSIONS: The differentiation between COVID-19 and NC could be well improved by using radiomics features, compared with traditional CT quantitative values.

Rethinking the geography of gentrification: From a scale perspective

This article proposes that the lens of scale may potentially yield fresh insights into the comparative research on gentrification. First, the flows of capital, people, and knowledge in re-scaling furnish a point of departure for a holistic theory of planetary gentrification and a vital reference point for comparison. Second, to harness upscaling and downscaling in tandem, comparative studies should adequately connect gentrification with similar regional/local ontologies to obtain greater ontological power. The disadvantaged should take advantage of a loose and shifting alliance among the pro-gentrification forces to find a “real choice” (instead of a “perfect choice”) for those affected. Moreover, a pragmatic solution is opprobrium against predatory flows, particularly the flows of capital, whose nature is defined by local peculiarities.

How to optimize the Radiology protocol during the global COVID-19 epidemic: Keypoints from Sichuan Provincial People's Hospital.

Currently, the COVID-19 pneumonia epidemic is spreading worldwide. Pulmonary imaging plays an important role. The pulmonary imaging (chest computed tomography and Digital radiography) are indispensable for definitive diagnosis and reexamination. It should be noted that nosocomial infection is not uncommon. Many cases including health workers are infected. This is the experience of our radiology department's protocols during the outbreak, we used this protocol to cope with the COVID-19 in Sichuan Province， besides，there is zero infection for health workers during the whole epidemic. So, we would like to share our experience to other radiologists to avoid the nosocomial infection as low as possible. We have six key points for updating the protocol in the epidemic period of COVID-19: 1. Triage system: three-level triage, 2. Maximum Protection Principle, 3. Technical operation principle: careful, fast and stable, 4. Radiologist's Responsibility and Notice, 5. Disinfection measures of machine room, 6. Hospital information construction, network office, accelerate the sharing of imaging, and carry out MDT consultation.

[Large- scale prospective clinical study on prophylactic intervention of COVID-19 in community population using Huoxiang Zhengqi Oral Liquid and Jinhao Jiere Granules].

To scientifically evaluate the intervention effect of Chinese medicine preventive administration(combined use of Huo-xiang Zhengqi Oral Liquid and Jinhao Jiere Granules) on community population in the case of coronavirus disease 2019(COVID-19), a large cohort, prospective, randomized, and parallel-controlled clinical study was conducted. Total 22 065 subjects were included and randomly divided into 2 groups. The non-intervention group was given health guidance only, while the traditional Chinese medicine(TCM) intervention group was given two coordinated TCM in addition to health guidance. The medical instructions were as follows. Huoxiang Zhengqi Oral Liquid: oral before meals, 10 mL/time, 2 times/day, a course of 5 days. Jinhao Jiere Granules: dissolve in boiling water and take after meals, 8 g/time, 2 times/day, a course of 5 days, followed up for 14 days, respectively. The study found that with the intake of medication, the incidence rate of TCM intervention group was basically maintained at a low and continuous stable level(0.01%-0.02%), while the non-intervention group showed an overall trend of continuous growth(0.02%-0.18%) from 3 to 14 days. No suspected or confirmed COVID-19 case occurred in either group. There were 2 cases of colds in the TCM intervention group and 26 cases in the non-intervention group. The incidence of colds in the TCM intervention group was significantly lower(P<0.05) than that in the non-intervention group. In the population of 16-60 years old, the incidence rate of non-intervention and intervention groups were 0.01% and 0.25%, respectively. The difference of colds incidence between the two groups was statistically significant(P<0.05). In the population older than 60 years old, they were 0.04% and 0.21%, respectively. The incidence of colds in the non-intervention group was higher than that in the intervention group, but not reaching statistical difference. The protection rate of TCM for the whole population was 91.8%, especially for the population of age 16-60(95.0%). It was suggested that TCM intervention(combined use of Huoxiang Zhengqi Oral Liquid and Jinhao Jiere Granules) could effectively protect community residents against respiratory diseases, such as colds, which was worthy of promotion in the community. In addition, in terms of safety, the incidence of adverse events and adverse reactions in the TCM intervention group was relatively low, which was basically consistent with the drug instructions.

Challenges of SARS-CoV-2 and lessons learnt from SARS in Guangdong Province, China.

With lessons learnt from the SARS outbreak in 2003, Guangdong Province is taking the lead in bringing COVID-19 under control by multiple strict regulations in combination with effective healthcare provision.