Detection of SARS-CoV-2 receptor binding domain using fluorescence probe and DNA flowers enabled by rolling circle amplification.

Using rolling circle amplification (RCA) and two different ways of signal readout, we developed analytical methods to detect the receptor-binding domain (RBD) of SARS-CoV-2 spike protein (S protein). We modified streptavidin-coated magnetic beads with an aptamer of RBD through a biotin-tagged complementary DNA strand (biotin-cDNA). Binding of RBD caused the aptamer to dissociate from the biotin-cDNA, making the cDNA available to initiate RCA on the magnetic beads. Detection of RBD was achieved using a dual signal output. For fluorescence signaling, the RCA products were mixed with a dsDNA probe labeled with fluorophore and quencher. Hybridization of the RCA products caused the dsDNA to separate and to emit fluorescence (λex = 488 nm, λem = 520 nm). To generate easily detectable UV-vis absorbance signal, the RCA amplification was extended to produce DNA flower to encapsulate horseradish peroxidase (HRP). The HRP-encapsulated DNA flower catalyzed a colorimetric reaction between H2O2 and 3,3',5,5'-tetramethylbenzidine (TMB) to generate an optical signal (λabs = 450 nm). The fluorescence and colorimetric assays for RBD have low detection limits (0.11 pg mL-1 and 0.904 pg mL-1) and a wide linear range (0.001-100 ng mL-1). For detection of RBD in human saliva, the recovery was 93.0-100% for the fluorescence assay and 87.2-107% for the colorimetric assay. By combining fluorescence and colorimetric detection with RCA, detection of the target RBD in human saliva was achieved with high sensitivity and selectivity.

Surgical workflow and infection prevention and control strategies for patients with COVID-19 during the epidemic in Children's Hospitals.

Background: This study sought to investigate the surgical workflow and practical effects of infection prevention and control in specialist pediatric hospitals during the Corona Virus Disease 2019 (COVID-19) epidemic to provide a foundation for ensuring the safety of children and medical staff. Methods: The Guidelines for the Management of Surgical Procedures and Infection Prevention and Control of COVID-19 Pneumonia in Children were formulated according to the industry specifications and standards, the prevention and control work system for hospitals in China, and the experiences of the Chinese Nursing Association in infection prevention and control in the operating room. These guidelines focus on the characteristics of children, and provide management priorities in relation to personnel management, infection prevention and control during surgery, intraoperative safety, and the cooperation of medical staff teams. These operation management and prevention and control strategies were applied to children who were suspected or confirmed to have COVID-19. Results: The operation process and prevention and control measures were effectively implemented. During the epidemic, a total of 219 surgeries which patients' COVID-19 nucleic test result are not out were completed. No medical staff or nosocomial infection occurred during the surgeries. Conclusions: As a special group, children are susceptible to COVID-19, and should receive special attention. As the only hospital designated to treat children with COVID-19 in Hubei Province, our hospital effectively implemented the infection prevention and control measures in surgery according to the characteristics of children. These measures ensured the safety of the surgeries and reduced the risk of infection in children and medical staff.

A novel inhalable quercetin-alginate nanogel as a promising therapy for acute lung injury.

BACKGROUND: Acute lung injury (ALI), a severe health-threatening disease, has a risk of causing chronic pulmonary fibrosis. Informative and powerful evidence suggests that inflammation and oxidative stress play a central role in the pathogenesis of ALI. Quercetin is well recognized for its excellent antioxidant and anti-inflammatory properties, which showed great potential for ALI treatment. However, the application of quercetin is often hindered by its low solubility and bioavailability. Therefore, to overcome these challenges, an inhalable quercetin-alginate nanogel (QU-Nanogel) was fabricated, and by this special "material-drug" structure, the solubility and bioavailability of quercetin were significantly enhanced, which could further increase the activity of quercetin and provide a promising therapy for ALI. RESULTS: QU-Nanogel is a novel alginate and quercetin based "material-drug" structural inhalable nanogel, in which quercetin was stabilized by hydrogen bonding to obtain a "co-construct" water-soluble nanogel system, showing antioxidant and anti-inflammatory properties. QU-Nanogel has an even distribution in size of less than 100 nm and good biocompatibility, which shows a stronger protective and antioxidant effect in vitro. Tissue distribution results provided evidence that the QU-Nanogel by ultrasonic aerosol inhalation is a feasible approach to targeted pulmonary drug delivery. Moreover, QU-Nanogel was remarkably reversed ALI rats by relieving oxidative stress damage and acting the down-regulation effects of mRNA and protein expression of inflammation cytokines via ultrasonic aerosol inhalation administration. CONCLUSIONS: In the ALI rat model, this novel nanogel showed an excellent therapeutic effect by ultrasonic aerosol inhalation administration by protecting and reducing pulmonary inflammation, thereby preventing subsequent pulmonary fibrosis. This work demonstrates that this inhalable QU-Nanogel may function as a promising drug delivery strategy in treating ALI.

Comparative research on nucleocapsid and spike glycoprotein as the rapid immunodetection targets of COVID-19 and establishment of immunoassay strips.

The SARS-CoV-2 virus responsible for coronavirus 2019 (COVID-19) poses a significant challenge to healthcare systems worldwide. According to the World Health Organization (WHO), the outbreak of COVID-19 has been a pandemic that infected more than 25.32 million people and caused more than 848.25 thousand deaths worldwide at the time of 1st September 2020. Despite governmental initiatives aimed to contain the spread of the disease, several countries are experiencing unmanageable increases in medical equipment and larger testing capacity. The current diagnosis based on nuclear acid requires specialized instruments, time-consuming, and laborious, the low-cost and convenient technologies were still urgently needed. Both spike and nucleocapsid are key structural proteins of COVID-19 with good immunogenicity, can serve as primary targets for immunoassay. After comparative research, we certified nucleocapsid antigen-monoclonal antibody (mAbs) system was more suitable for the COVID-19 immunodetection. Subsequently, we designed a rapid test strip based on it that can be used in large-scale screening of COVID-19 in population and more suitable for some remote and special needs areas were restricted by a medical condition or for quick and large quantities of screenings.

Psychological Impact of the COVID-19 Outbreak on Nurses in China: A Nationwide Survey During the Outbreak.

Background: The COVID-19 pandemic is a major public health issue and challenge to health professionals. In similar epidemics, nurses experienced more distress than other providers. Methods: We surveyed both on-duty nurses caring for infected patients and second-line nurses caring for uninfected patients from Hubei and other provinces throughout China. Results: We received completed surveys from 1,364 nurses from 22 provinces: 658 front-line and 706 second-line nurses. The median (IQR) GHQ-28 score of all nurses was 17 (IQR 11-24). The overall incidence of mild-to-moderate distress (GHQ score > 5) was 28%; that for severe distress (GHQ score > 11) was 6%. The incidence of mild-to-moderate distress in the second-line nurses was higher than that in the front-line nurses (31 vs. 25%; OR, 0.74; 95 CI, 0.58-0.94). Living alone (OR, 0.62; 95% CI, 0.44-0.86) and feeling supported (OR, 0.82, 95% CI, 0.74-0.90) independently predicted lower anxiety. Conclusions: During the COVID-19 pandemic, the psychological problems of all nurses were generally serious. The interviewed second-line nurses face more serious issues than the front-line nurses.

Digestive system manifestations and clinical significance of coronavirus disease 2019: A systematic literature review.

BACKGROUND AND AIM: A worldwide outbreak of coronavirus disease 2019 (COVID-19) has drawn global attention. Several reports have described the gastrointestinal (GI) manifestations in the infected patients. The systematic review was designed to highlight the gaps in our knowledge about the prevalence and clinical significance of GI symptoms in patients with COVID-19. METHODS: We searched PubMed database and Google articles published in both English and Chinese up to June 3, 2020, using search terms "clinical features," "2019 novel coronavirus," "2019-nCoV," "COVID-19," or "SARS-Cov-2." Observational studies, case reports, or letters describing the clinical features or observational studies regarding the detection and/or isolation of severe acute respiratory syndrome coronavirus 2 viruses in stools were included. RESULTS: A total of 22 publications were finally selected. It was reported that GI symptoms occurred in about 3-40.7% of patients. GI manifestations included nausea, diarrhea, anorexia, vomiting, abdominal pain, belching, abdominal distension, and GI hemorrhage. Diarrhea was the most common GI symptom. Infected patients had various degrees of liver dysfunction, and the severity of liver dysfunction was significantly associated with the severity of the disease. Therapy focusing on digestive system like liver supportive therapy or nutrition support or probiotics has been demonstrated to be effective interventions, which greatly improve prognosis. Fecal-oral transmission route is a potential risk for transmission. CONCLUSIONS: GI symptoms are common in COVID-19. Strengthening the recognition on abnormalities in digestive system of patients with COVID-19 is crucial for early identification and timely treatment, especially for those atypical patients. Hygiene protection and keeping the drainpipe free flowing are necessary for everyone.

Single-Cell Sequencing of Glioblastoma Reveals Central Nervous System Susceptibility to SARS-CoV-2.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the recent global COVID-19 outbreak, which led to a public health emergency. Entry of SARS-CoV-2 into human cells is dependent on the SARS-CoV receptor, angiotensin converting enzyme 2 (ACE2) receptor, and cathepsin. Cathepsin degrades the spike protein (S protein), which results in the entry of viral nucleic acid into the human host cell. METHODS: We explored the susceptibility of the central nervous system (CNS) to SARS-CoV-2 infection using single-cell transcriptome analysis of glioblastoma. RESULTS: The results showed that ACE2 expression is relatively high in endothelial cells (ECs), bone marrow mesenchymal stem cells (BMSCs), and neural precursor cells (NPCs). Cathepsin B (Cat B) and cathepsin (Cat L) were also strongly expressed in various cell clusters within the glioblastoma microenvironment. Immunofluorescence staining of glioma and normal brain tissue chips further confirmed that ACE2 expression co-localized with CD31, CD73, and nestin, which confirmed the susceptibility to SARS-CoV-2 of nervous system cells, including ECs, BMSCs, and NPCs, from clinical specimens. CONCLUSIONS: These findings reveal the mechanism of SARS-CoV-2 neural invasion and suggest that special attention should be paid to SARS-CoV-2-infected patients with neural symptoms, especially those who suffered a glioma.

Prevalence and associated factors of depression and anxiety among nurses during the outbreak of COVID-19 in China: A cross-sectional study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a public health emergency of international concern and has caused traumatic experience for nurses worldwide. However, the prevalence of depression and anxiety symptoms in nurses, and how psychosocial factors influence nurses in this public crisis are unknown. OBJECTIVES: To determine the effect of COVID-19 on the mental health of nurses and the prevalence of anxiety and depression symptoms among nurses in China during the outbreak. DESIGN: A cross-sectional study. SETTINGS AND PARTICIPANTS: A total of 3,228 nurses in Sichuan Province and Wuhan City were selected by convenience sampling. All participants were invited to complete the questionnaire through WeChat from January 27 to February 3, 2020. METHODS: A self-reported questionnaire combining depression and anxiety scale was used to collect data anonymously. Binary and multivariate logistic regression was applied to measure the odds of psychosocial factors of anxiety and depression and perceived health, respectively. RESULTS: The total incidence of depression (34.3%) and anxiety (18.1%) during the COVID-19 outbreak was lower than that during the SARS outbreak; however, the rate of depression in our study (47.1%) was high and similar in a recent study (50.4%) about the health care workers exposed to COVID-19 in China. The results indicated that COVID-19-related stress, relationship quality with family, and demographic characteristics were associated with depression, anxiety, and perceived health status. Furthermore, the prevalence of depression was similar between nurses working in low-risk COVID-19 wards was as high as working in high-risk COVID-19 wards (OR, 1.078; 95% CI, 0.784-1.481). CONCLUSIONS: Our study revealed the high prevalence of depression and anxiety among nurses during the outbreak of COVID-19. COVID-19 factors and psychosocial factors were associated with mental health of nurses. The results suggest that hospitals should implement effective mental health promotion programs focused on occupational safety and family support to improve the well-being of nurses.

Development of a droplet digital PCR for detection and quantification of porcine epidemic diarrhea virus.

Porcine epidemic diarrhea, a disease caused by porcine epidemic diarrhea virus (PEDV), results in large economic losses to the global swine industry. To manage this disease effectively, it is essential to detect PEDV early and accurately. We developed a sensitive and accurate droplet digital PCR (ddPCR) assay to detect PEDV. The optimal primer-to-probe concentration and melting temperature were identified as 300:200 nM and 59.2°C, respectively. The specificity of the ddPCR assay was confirmed by negative test results for common swine pathogens. The detection limit for the ddPCR was 0.26 copies/µL, which is a 5.7-fold increase in sensitivity compared to that of real-time PCR (rtPCR). Both ddPCR and rtPCR assays exhibited good linearity, although ddPCR provided higher sensitivity for clinical detection compared to that of rtPCR. Our ddPCR methodology provides a promising tool for evaluating the PEDV viral load when used for clinical testing, particularly for detecting samples with low-copy viral loads.

Clinical features and outcomes of pregnant women with COVID-19: a systematic review and meta-analysis.

BACKGROUND: The recent COVID-19 outbreak in Wuhan, China, has quickly spread throughout the world. In this study, we systematically reviewed the clinical features and outcomes of pregnant women with COVID-19. METHODS: PubMed, Web of Science, EMBASE and MEDLINE were searched from January 1, 2020, to April 16, 2020. Case reports and case series of pregnant women infected with SARS-CoV-2 were included. Two reviewers screened 366 studies and 14 studies were included. Four reviewers independently extracted the features from the studies. We used a random-effects model to analyse the incidence (P) and 95% confidence interval (95% CI). Heterogeneity was assessed using the I2 statistic. RESULTS: The meta-analysis included 236 pregnant women with COVID-19. The results were as follows: positive CT findings (71%; 95% CI, 0.49-0.93), caesarean section (65%; 95% CI, 0.42-0.87), fever (51%; 95% CI, 0.35-0.67), lymphopenia (49%; 95% CI, 0.29-0.70), coexisting disorders (33%; 95% CI, 0.21-0.44), cough (31%; 95% CI, 0.23-0.39), fetal distress (29%; 95% CI, 0.08-0.49), preterm labor (23%; 95% CI, 0.14-0.32), and severe case or death (12%; 95% CI, 0.03-0.20). The subgroup analysis showed that compared with non-pregnant patients, pregnant women with COVID-19 had significantly lower incidences of fever (pregnant women, 51%; non-pregnant patients, 91%; P < 0.00001) and cough (pregnant women, 31%; non-pregnant patients, 67%; P < 0.0001). CONCLUSIONS: The incidences of fever, cough and positive CT findings in pregnant women with COVID-19 are less than those in the normal population with COVID-19, but the rate of preterm labor is higher among pregnant with COVID-19 than among normal pregnant women. There is currently no evidence that COVID-19 can spread through vertical transmission.

Spatiotemporal distribution and trend of COVID-19 in the Yangtze River Delta region of the People's Republic of China.

An outbreak of atypical pneumonia, now called COVID-19 and known to be caused by the novel coronavirus SARS-CoV-2, first detected in Wuhan, Hubei Province of the People's Republic of China in December 2019 and afterwards rapidly spread worldwide. Wuhan and the Yangtze River Delta (YRD) region implemented first-level public health emergency responses to stop the spread of the virus on January 23rd, 2020. We tracked the geographical gravity centre of the disease and calculated spatial autocorrelation to explore the spatiotemporal patterns of distribution of imported and locally disseminated COVID-19 cases under the emergency-response control measure. We also applied polynomial regression analysis to estimate the trend of the COVID-19 in the YRD region before and after the control activities against the spread of the infection were instituted. The results show that the control measures applied have been effective. And, in the YRD region, areas with a large influx of population flow from Wuhan and Hubei Province had high risks of COVID-19. Therefore, identification of the spatiotemporal trends should be the first step when developing effective policies to manage and control any new epidemic. The results are not only informative locally but also useful for the rest of the world.