The clinical features and immune responses of asymptomatic individuals infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have not been well described. We studied 37 ...asymptomatic individuals in the Wanzhou District who were diagnosed with RT-PCR-confirmed SARS-CoV-2 infections but without any relevant clinical symptoms in the preceding 14 d and during hospitalization. Asymptomatic individuals were admitted to the government-designated Wanzhou People's Hospital for centralized isolation in accordance with policy
. The median duration of viral shedding in the asymptomatic group was 19 d (interquartile range (IQR), 15-26 d). The asymptomatic group had a significantly longer duration of viral shedding than the symptomatic group (log-rank P = 0.028). The virus-specific IgG levels in the asymptomatic group (median S/CO, 3.4; IQR, 1.6-10.7) were significantly lower (P = 0.005) relative to the symptomatic group (median S/CO, 20.5; IQR, 5.8-38.2) in the acute phase. Of asymptomatic individuals, 93.3% (28/30) and 81.1% (30/37) had reduction in IgG and neutralizing antibody levels, respectively, during the early convalescent phase, as compared to 96.8% (30/31) and 62.2% (23/37) of symptomatic patients. Forty percent of asymptomatic individuals became seronegative and 12.9% of the symptomatic group became negative for IgG in the early convalescent phase. In addition, asymptomatic individuals exhibited lower levels of 18 pro- and anti-inflammatory cytokines. These data suggest that asymptomatic individuals had a weaker immune response to SARS-CoV-2 infection. The reduction in IgG and neutralizing antibody levels in the early convalescent phase might have implications for immunity strategy and serological surveys.
Abstract
Background
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel β-coronavirus, causes severe pneumonia and has spread throughout the globe rapidly. The disease associated ...with SARS-CoV-2 infection is named coronavirus disease 2019 (COVID-19). To date, real-time reverse-transcription polymerase chain reaction (RT-PCR) is the only test able to confirm this infection. However, the accuracy of RT-PCR depends on several factors; variations in these factors might significantly lower the sensitivity of detection.
Methods
In this study, we developed a peptide-based luminescent immunoassay that detected immunoglobulin (Ig)G and IgM. The assay cutoff value was determined by evaluating the sera from healthy and infected patients for pathogens other than SARS-CoV-2.
Results
To evaluate assay performance, we detected IgG and IgM in the sera from confirmed patients. The positive rate of IgG and IgM was 71.4% and 57.2%, respectively.
Conclusions
Therefore, combining our immunoassay with real-time RT-PCR might enhance the diagnostic accuracy of COVID-19.
A peptide-based magnetic chemiluminescence enzyme immunoassay for the detection of SARS-CoV-2 antibodies was developed; 71.4% (197 of 276) and 57.2% (158 of 276) of the COVID-19 inpatients were positive for IgG and IgM against SARS-CoV-2.
We report acute antibody responses to SARS-CoV-2 in 285 patients with COVID-19. Within 19 days after symptom onset, 100% of patients tested positive for antiviral immunoglobulin-G (IgG). ...Seroconversion for IgG and IgM occurred simultaneously or sequentially. Both IgG and IgM titers plateaued within 6 days after seroconversion. Serological testing may be helpful for the diagnosis of suspected patients with negative RT-PCR results and for the identification of asymptomatic infections.
This study aimed to determine long non‐coding RNA (lncRNA) small nucleolar RNA host gene 14 (SNHG14) expression in pancreatic cancer and to explore the potential molecular actions of SNHG14 in ...mediating pancreatic cancer progression. Gene expression was detected by quantitative real‐time PCR. Cell proliferation, growth and invasion were detected by respective CCK‐8, colony formation, and transwell invasion assays. Protein levels were measured by Western blotting. Cell apoptosis and caspase‐3 activity were detected by flow cytometry and caspase‐3 activity assay. The link between miR‐613 and its targets was evaluated by luciferase reporter assay. In vivo tumour growth was evaluated using a xenograft model of nude mice. SNHG14 expression was up‐regulated in cancerous tissues from pancreatic cancer patients. High expression of SNHG14 was associated with poor tumour differentiation, advanced TNM stage and nodal metastasis. SNHG14 overexpression enhanced cell proliferative, growth and invasive abilities, and suppressed apoptotic rates and caspase‐3 activity in pancreatic cancer cells, while SNHG14 knockdown exerted opposite effects. Mechanistic studies revealed that miR‐613 was targeted by SNHG14, and Annexin A2 (ANXA2) was targeted and inversely regulated by miR‐613 in pancreatic cancer cells. In vivo studies showed that SNHG14 knockdown attenuated tumour growth. MiR‐613 was down‐regulated and ANXA2 was up‐regulated in the pancreatic cancer tissues, and SNHG14 expression levels were inversely correlated with miR‐613 expression levels and positively correlated with the ANXA2 mRNA expression levels. Collectively, our results suggest that SNHG14 potentiates pancreatic cancer progression through modulation of annexin A2 expression via acting as a competing endogenous RNA for miR‐613.
Objective
Few studies have explored the clinical features in children infected with SARS‐CoV‐2 and other common respiratory viruses, including respiratory syncytial virus (RSV), Influenza virus (IV), ...and adenovirus (ADV). Herein, we reported the clinical characteristics and cytokine profiling in children with COVID‐19 or other acute respiratory tract infections (ARTI).
Methods
We enrolled 20 hospitalized children confirmed as COVID‐19 positive, 58 patients with ARTI, and 20 age and sex‐matched healthy children. The clinical information and blood test results were collected. A total of 27 cytokines and chemokines were measured and analyzed.
Results
The median age in the COVID‐19 positive group was 14.5 years, which was higher than that of the ARTI groups. Around one‐third of patients in the COVID‐19 group experienced moderate fever, with a peak temperature of 38.27°C. None of the patients displayed wheezing or dyspnea. In addition, patients in the COVID‐19 group had lower white blood cells, platelet counts as well as a neutrophil‐lymphocyte ratio. Lower serum concentrations of 14 out of 27 cytokines were observed in the COVID‐19 group than in healthy individuals. Seven cytokines (IL‐1Ra, IL‐1β, IL‐9, IL‐10, TNF‐α, MIP‐1α, and VEGF) changed serum concentration in COVID‐19 compared with other ARTI groups.
Conclusion
Patients with COVID‐19 were older and showed milder symptoms and a favorable prognosis than ARTI caused by RSV, IV, and ADV. There was a low grade or constrained innate immune reaction in children with mild COVID‐19.
Abstract
Background
Coronavirus disease 2019 (COVID-19) is a global pandemic with no licensed vaccine or specific antiviral agents for therapy. Little is known about the longitudinal dynamics of ...severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–specific neutralizing antibodies (NAbs) in patients with COVID-19.
Methods
Blood samples (n = 173) were collected from 30 patients with COVID-19 over a 3-month period after symptom onset and analyzed for SARS-CoV-2–specific NAbs using the lentiviral pseudotype assay, coincident with the levels of IgG and proinflammatory cytokines.
Results
SARS-CoV-2–specific NAb titers were low for the first 7–10 days after symptom onset and increased after 2–3 weeks. The median peak time for NAbs was 33 days (interquartile range IQR, 24–59 days) after symptom onset. NAb titers in 93.3% (28/30) of the patients declined gradually over the 3-month study period, with a median decrease of 34.8% (IQR, 19.6–42.4%). NAb titers increased over time in parallel with the rise in immunoglobulin G (IgG) antibody levels, correlating well at week 3 (r = 0.41, P < .05). The NAb titers also demonstrated a significant positive correlation with levels of plasma proinflammatory cytokines, including stem cell factor (SCF), TNF-related apoptosis-inducing ligand (TRAIL), and macrophage colony-stimulating factor (M-CSF).
Conclusions
These data provide useful information regarding dynamic changes in NAbs in patients with COVID-19 during the acute and convalescent phases.
Abstract
Background
Alignment is indispensable for the foot and ankle function, especially in the hindfoot alignment. In the preoperative planning of patients with varus or valgus deformity, the ...precise measurement of the hindfoot alignment is important. A new method of photographing and measuring hindfoot alignment based on X-ray was proposed in this study, and it was applied in the assessment of flatfoot.
Methods
This study included 28 patients (40 feet) with flatfeet and 20 volunteers (40 feet) from January to December 2018. The hindfoot alignment shooting stand independently designed by our department was used to take hindfoot alignment X-rays at 10 degree, 15 degree, 20 degree, 25 degree, and 30 degree. We measured the modified tibio-hindfoot angle (THA) at the standard hindfoot aligment position (shooting at 20 degree) and evaluated consistency with the van Dijk method and the modified van Dijk method. In addition, we observed the visibility of the tibiotalar joint space from all imaging data at five projection angles and evaluated the consistency of the modified THA method at different projection angles. The angle of hindfoot valgus of flatfoot patients was measured using the modified THA method.
Results
The mean THA in the standard hindfoot aligment view in normal people was significantly different among the three evaluation methods (P < .001). The results from the modified THA method were significantly larger than those from the Van Dijk method (P < .001) and modified Van Dijk method (P < .001). There was no significant difference between the results of the modified THA method and the weightbearing CT (P = .605), and the intra- and intergroup consistency were the highest in the modified THA group. The tibiotalar space in the normal group was visible in all cases at 10 degree, 15 degree, and 20 degree; visible in some cases at 25 degree; and not visible in all cases at 30 degree. In the flatfoot group, the tibiotalar space was visible in all cases at 10 degree, visible in some cases at 15 degree and 20 degree, and not visible in all cases at 25 degree and 30 degree. In the normal group, the modified THA was 4.84 ± 1.81 degree at 10 degree, 4.96 ± 1.77 degree at 15 degree, and 4.94 ± 2.04 degree at 20 degree. No significant differences were found among the three groups (P = .616). In the flatfoot group, the modified THA of 18 feet, which was visible at 10 degree, 15 degree and 20 degree, was 13.58 ± 3.57 degree at 10 degree, 13.62 ± 3.83 degree at 15 degree and 13.38 ± 4.06 degree at 20 degree. There were no significant differences among the three groups (P = .425).
Conclusions
The modified THA evaluation method is simple to use and has high inter- and intragroup consistency. It can be used to evaluate hindfoot alignment. For patients with flatfeet, the 10 degree position view and modified THA measurement can be used to evaluate hindfoot valgus.
Hepatitis B virus (HBV) infection remains a major health problem worldwide. Maintenance of the covalently closed circular DNA (cccDNA), which serves as a template for HBV RNA transcription, is ...responsible for the failure of eradicating chronic HBV during current antiviral therapy. cccDNA is assembled with cellular histone proteins into chromatin, but little is known about the regulation of HBV chromatin by histone posttranslational modifications. In this study, we identified silent mating type information regulation 2 homolog 3 (SIRT3) as a host factor restricting HBV transcription and replication by screening seven members of the sirtuin family, which is the class III histone deacetylase. Ectopic SIRT3 expression significantly reduced total HBV RNAs, 3.5‐kb RNA, as well as replicative intermediate DNA in HBV‐infected HepG2‐Na+/taurocholate cotransporting polypeptide cells and primary human hepatocytes. In contrast, gene silencing of SIRT3 promoted HBV transcription and replication. A mechanistic study found that nuclear SIRT3 was recruited to the HBV cccDNA, where it deacetylated histone 3 lysine 9. Importantly, occupancy of SIRT3 on cccDNA could increase the recruitment of histone methyltransferase suppressor of variegation 3‐9 homolog 1 to cccDNA and decrease recruitment of SET domain containing 1A, leading to a marked increase of trimethyl‐histone H3 (Lys9) and a decrease of trimethyl‐histone H3 (Lys4) on cccDNA. Moreover, SIRT3‐mediated HBV cccDNA transcriptional repression involved decreased binding of host RNA polymerase II and transcription factor Yin Yang 1 to cccDNA. Finally, hepatitis B viral X protein could relieve SIRT3‐mediated cccDNA transcriptional repression by inhibiting both SIRT3 expression and its recruitment to cccDNA. Conclusion: SIRT3 is a host factor epigenetically restricting HBV cccDNA transcription by acting cooperatively with histone methyltransferase; these data provide a rationale for the use of SIRT3 activators in the prevention or treatment of HBV infection. (Hepatology 2018).
Experimental observations have shown that peptides are chemically modified under plasma treatment, which impacts the function and lifetime of a protein. This paper investigates the interactions of ...reactive oxygen species (ROS) produced in atmospheric plasmas and peptides. Results show that the reactions typically start with the H ion from the side chain of amino acids. As the reactions continue, the introduction of O atoms is the most common reaction, and the formation of double C = C bonds, detachment of carboxyl groups, and cleavage of the ring are also observed. Moreover, the degree of oxidative modification of the peptides increases with increasing doses of ROS. This study reveals the formation and breaking of chemical bonds and the generation of new reactive groups in the structure of peptides under plasma treatment, which enables us to understand the mechanisms of plasma medicine deeply.
In this manuscript, we present a modeling study on the interactions of CAP and peptides by a reactive molecular dynamic simulation. The formation and breaking of chemical bonds and the generation of new reactive groups on the structure of peptides are carefully investigated upon the impact of reactive oxygen species, and the final products are given, which agree well with the experimental observation.
Current antiviral therapies help keep HBV under control, but they are not curative, as they are unable to eliminate the intracellular viral replication intermediate termed covalently closed circular ...DNA (cccDNA). Therefore, there remains an urgent need to develop strategies to cure CHB. Functional silencing of cccDNA is a crucial curative strategy that may be achieved by targeting the viral protein HBx.
We screened 2,000 small-molecule compounds for their ability to inhibit HiBiT-tagged HBx (HiBiT-HBx) expression by using a HiBiT lytic detection system. The antiviral activity of a candidate compound and underlying mechanism of its effect on cccDNA transcription were evaluated in HBV-infected cells and a humanised liver mouse model.
Dicoumarol, an inhibitor of NAD(P)H:quinone oxidoreductase 1 (NQO1), significantly reduced HBx expression. Moreover, dicoumarol showed potent antiviral activity against HBV RNAs, HBV DNA, HBsAg and HBc protein in HBV-infected cells and a humanised liver mouse model. Mechanistic studies demonstrated that endogenous NQO1 binds to and protects HBx protein from 20S proteasome-mediated degradation. NQO1 knockdown or dicoumarol treatment significantly reduced the recruitment of HBx to cccDNA and inhibited the transcriptional activity of cccDNA, which was associated with the establishment of a repressive chromatin state. The absence of HBx markedly blocked the antiviral effect induced by NQO1 knockdown or dicoumarol treatment in HBV-infected cells.
Herein, we report on a novel small molecule that targets HBx to combat chronic HBV infection; we also reveal that NQO1 has a role in HBV replication through the regulation of HBx protein stability.
Current antiviral therapies for hepatitis B are not curative because of their inability to eliminate covalently closed circular DNA (cccDNA), which persists in the nuclei of infected cells. HBV X (HBx) protein has an important role in regulating cccDNA transcription. Thus, targeting HBx to silence cccDNA transcription could be an important curative strategy. We identified that the small molecule dicoumarol could block cccDNA transcription by promoting HBx degradation; this is a promising therapeutic strategy for the treatment of chronic hepatitis B.
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•Dicoumarol, a competitive NADPH quinone oxidoreductase (NQO1) inhibitor, is identified as an inhibitor of HBx expression.•NQO1 stabilises HBx protein by inhibiting 20S proteasome-mediated protein degradation.•NQO1 knockdown or dicoumarol treatment blocks cccDNA transcription by establishing a repressive chromatin structure.•Dicoumarol exhibits potent antiviral activity in HBV-infected hepatocytes and a humanised liver mouse model.
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