Accurate quantification of DNA using on-site PCR (osPCR) by characterizing DNA amplification at single-molecule resolution.

Despite the need in various applications, accurate quantification of nucleic acids still remains a challenge. The widely-used qPCR has reduced accuracy at ultralow template concentration and is susceptible to nonspecific amplifications. The more recently developed dPCR is costly and cannot handle high-concentration samples. We combine the strengths of qPCR and dPCR by performing PCR in silicon-based microfluidic chips and demonstrate high quantification accuracy in a large concentration range. Importantly, at low template concentration, we observe on-site PCR (osPCR), where only certain sites of the channel show amplification. The sites have almost identical ct values, showing osPCR is a quasi-single molecule phenomenon. Using osPCR, we can measure both the ct values and the absolute concentration of templates in the same reaction. Additionally, osPCR enables identification of each template molecule, allowing removal of nonspecific amplification during quantification and greatly improving quantification accuracy. We develop sectioning algorithm that improves the signal amplitude and demonstrate improved detection of COVID in patient samples.

Characteristics and result reporting of registered COVID-19 clinical trials of Chinese and Indian traditional medicine: A comparative analysis.

Objective: To assess the main characteristics and result reporting of registered COVID-19 interventional trials of traditional Chinese medicine and traditional Indian medicine. Materials and methods: We assessed design quality and result reporting of COVID-19 trials of traditional Chinese medicine (TCM) and traditional Indian medicine (TIM) registered before 10 February 2021, respectively, on Chinese Clinical Trial Registry (ChiCTR) and Clinical Trial Registry-India (CTRI). Comparison groups included registered COVID-19 trials of conventional medicine conducted in China (WMC), India (WMI), and in other countries (WMO). Cox regression analysis was used to assess the association between time from trial onset to result reporting and trial characteristics. Results: The proportion of COVID-19 trials investigating traditional medicine was 33.7% (130/386) among trials registered on ChiCTR, and 58.6% (266/454) on CTRI. Planned sample sizes were mostly small in all COVID-19 trials (median 100, IQR: 50-200). The proportion of trials that were randomized was 75.4 and 64.8%, respectively, for the TCM and TIM trials. Blinding measures were used in 6.2% of the TCM trials, and 23.6% of the TIM trials. Cox regression analysis revealed that planned COVID-19 clinical trials of traditional medicine were less likely to have results reported than trials of conventional medicine (hazard ratio 0.713, 95% confidence interval: 0.541-0.939; p = 0.0162). Conclusion: There were considerable between-country and within-country differences in design quality, target sample size, trial participants, and reporting of trial results. Registered COVID-19 clinical trials of traditional medicine were less likely to report results than trials of conventional medicine.

Investigation on knowledge, belief and practice of COVID-19 during the epidemic

Objective: To examine the impact of the outbreak of novel Coronavirus disease (COVlD-19) upon public health-related knowledge. belief and practice among the public in China for providing references to public health decision-making.

Voluntary disclosure of pandemic exposure and stock price crash risk.

We examine whether a firm's voluntary disclosure of pandemic exposure increases stock price crash risk in a turbulent stock market caused by the spread of COVID-19 and other epidemic diseases. Pandemic risk is an unprecedented type of economic shock that alters the firm's stock price. Using an innovative firm-level pandemic exposure dataset based on the textual analysis of earnings conference calls, we show that there is a strong positive correlation between firm-level disclosure of pandemic exposure and one-quarter-ahead stock price crash risk.

Cytokine Signature Induced by SARS-CoV-2 Spike Protein in a Mouse Model.

Although COVID-19 has become a major challenge to global health, there are currently no efficacious agents for effective treatment. Cytokine storm syndrome (CSS) can lead to acute respiratory distress syndrome (ARDS), which contributes to most COVID-19 mortalities. Research points to interleukin 6 (IL-6) as a crucial signature of the cytokine storm, and the clinical use of the IL-6 inhibitor tocilizumab shows potential for treatment of COVID-19 patient. In this study, we challenged wild-type and adenovirus-5/human angiotensin-converting enzyme 2-expressing BALB/c mice with a combination of polyinosinic-polycytidylic acid and recombinant SARS-CoV-2 spike-extracellular domain protein. High levels of TNF-α and nearly 100 times increased IL-6 were detected at 6 h, but disappeared by 24 h in bronchoalveolar lavage fluid (BALF) following immunostimulant challenge. Lung injury observed by histopathologic changes and magnetic resonance imaging at 24 h indicated that increased TNF-α and IL-6 may initiate CSS in the lung, resulting in the continual production of inflammatory cytokines. We hypothesize that TNF-α and IL-6 may contribute to the occurrence of CSS in COVID-19. We also investigated multiple monoclonal antibodies (mAbs) and inhibitors for neutralizing the pro-inflammatory phenotype of COVID-19: mAbs against IL-1α, IL-6, TNF-α, and granulocyte-macrophage colony-stimulating factor (GM-CSF), and inhibitors of p38 and JAK partially relieved CSS; mAbs against IL-6, TNF-α, and GM-CSF, and inhibitors of p38, extracellular signal-regulated kinase, and myeloperoxidase somewhat reduced neutrophilic alveolitis in the lung. This novel murine model opens a biologically safe, time-saving avenue for clarifying the mechanism of CSS/ARDS in COVID-19 and developing new therapeutic drugs.

Recombinant SARS-CoV-2 RBD with a built in T helper epitope induces strong neutralization antibody response.

Without approved vaccines and specific treatments, COVID-19 is spreading around the world with above 26 million cases and approximately 864 thousand deaths until now. An efficacious and affordable vaccine is urgently needed. The Val308 - Gly548 of spike protein of SARS-CoV-2 linked with Gln830 - Glu843 of Tetanus toxoid (TT peptide) (designated as S1-4) and without TT peptide (designated as S1-5) were expressed and renatured. The antigenicity and immunogenicity of S1-4 were evaluated by Western Blotting (WB) in vitro and immune responses in mice, respectively. The protective efficiency was measured preliminarily by microneutralization assay (MN50). The soluble S1-4 and S1-5 protein was prepared to high homogeneity and purity. Adjuvanted with Alum, S1-4 protein stimulated a strong antibody response in immunized mice and caused a major Th2-type cellular immunity supplemented with Th1-type immunity. Furthermore, the immunized sera could protect the Vero E6 cells from SARS-CoV-2 infection with neutralizing antibody titer 256. Recombinant SARS-CoV-2 RBD with a built in T helper epitope could stimulate both strong humoral immunity supplemented with cellular immunity in mice, demonstrating that it could be a promising subunit vaccine candidate.