The outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in China and rapidly spread worldwide. To prevent SARS-CoV-2 ...dissemination, understanding the in vivo characteristics of SARS-CoV-2 is a high priority. We report a ferret model of SARS-CoV-2 infection and transmission that recapitulates aspects of human disease. SARS-CoV-2-infected ferrets exhibit elevated body temperatures and virus replication. Although fatalities were not observed, SARS-CoV-2-infected ferrets shed virus in nasal washes, saliva, urine, and feces up to 8 days post-infection. At 2 days post-contact, SARS-CoV-2 was detected in all naive direct contact ferrets. Furthermore, a few naive indirect contact ferrets were positive for viral RNA, suggesting airborne transmission. Viral antigens were detected in nasal turbinate, trachea, lungs, and intestine with acute bronchiolitis present in infected lungs. Thus, ferrets represent an infection and transmission animal model of COVID-19 that may facilitate development of SARS-CoV-2 therapeutics and vaccines.
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•SARS-CoV-2-infected ferrets exhibit elevated body temperature and virus replication•SARS-CoV-2 is shed in nasal washes, saliva, urine and feces•SARS-CoV-2 is effectively transmitted to naive ferrets by direct contact•SARS-CoV-2 infection leads acute bronchiolitis in infected ferrets
The outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapidly spreads, leading to a pandemic infection. Kim et al. show that ferrets are highly susceptible to SARS-CoV-2 infection and effectively transmit the virus by direct or indirect contact, recapitulating human infection and transmission.
infection and a family history of gastric cancer are the main risk factors for gastric cancer. Whether treatment to eradicate
can reduce the risk of gastric cancer in persons with a family history of ...gastric cancer in first-degree relatives is unknown.
In this single-center, double-blind, placebo-controlled trial, we screened 3100 first-degree relatives of patients with gastric cancer. We randomly assigned 1838 participants with
infection to receive either eradication therapy (lansoprazole 30 mg, amoxicillin 1000 mg, and clarithromycin 500 mg, each taken twice daily for 7 days) or placebo. The primary outcome was development of gastric cancer. A prespecified secondary outcome was development of gastric cancer according to
eradication status, assessed during the follow-up period.
A total of 1676 participants were included in the modified intention-to-treat population for the analysis of the primary outcome (832 in the treatment group and 844 in the placebo group). During a median follow-up of 9.2 years, gastric cancer developed in 10 participants (1.2%) in the treatment group and in 23 (2.7%) in the placebo group (hazard ratio, 0.45; 95% confidence interval CI, 0.21 to 0.94; P = 0.03 by log-rank test). Among the 10 participants in the treatment group in whom gastric cancer developed, 5 (50.0%) had persistent
infection. Gastric cancer developed in 0.8% of participants (5 of 608) in whom
infection was eradicated and in 2.9% of participants (28 of 979) who had persistent infection (hazard ratio, 0.27; 95% CI, 0.10 to 0.70). Adverse events were mild and were more common in the treatment group than in the placebo group (53.0% vs. 19.1%; P<0.001).
Among persons with
infection who had a family history of gastric cancer in first-degree relatives,
eradication treatment reduced the risk of gastric cancer. (Funded by the National Cancer Center, South Korea; ClinicalTrials.gov number, NCT01678027.).
For wireless charging of electric vehicle (EV) batteries, high-frequency magnetic fields are generated from magnetically coupled coils. The large air-gap between two coils may cause high leakage of ...magnetic fields and it may also lower the power transfer efficiency (PTE). For the first time, in this paper, we propose a new set of coil design formulas for high-efficiency and low harmonic currents and a new design procedure for low leakage of magnetic fields for high-power wireless power transfer (WPT) system. Based on the proposed design procedure, a pair of magnetically coupled coils with magnetic field shielding for a 1-kW-class golf-cart WPT system is optimized via finite-element simulation and the proposed design formulas. We built a 1-kW-class wireless EV charging system for practical measurements of the PTE, the magnetic field strength around the golf cart, and voltage/current spectrums. The fabricated system has achieved a PTE of 96% at the operating frequency of 20.15 kHz with a 156-mm air gap between the coils. At the same time, the highest magnetic field strength measured around the golf cart is 19.8 mG, which is far below the relevant electromagnetic field safety guidelines (ICNIRP 1998/2010). In addition, the third harmonic component of the measured magnetic field is 39 dB lower than the fundamental component. These practical measurement results prove the effectiveness of the proposed coil design formulas and procedure of a WPT system for high-efficiency and low magnetic field leakage.
Vaccines and therapeutics are urgently needed for the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we screen human monoclonal antibodies (mAb) targeting the ...receptor binding domain (RBD) of the viral spike protein via antibody library constructed from peripheral blood mononuclear cells of a convalescent patient. The CT-P59 mAb potently neutralizes SARS-CoV-2 isolates including the D614G variant without antibody-dependent enhancement effect. Complex crystal structure of CT-P59 Fab/RBD shows that CT-P59 blocks interaction regions of RBD for angiotensin converting enzyme 2 (ACE2) receptor with an orientation that is notably different from previously reported RBD-targeting mAbs. Furthermore, therapeutic effects of CT-P59 are evaluated in three animal models (ferret, hamster, and rhesus monkey), demonstrating a substantial reduction in viral titer along with alleviation of clinical symptoms. Therefore, CT-P59 may be a promising therapeutic candidate for COVID-19.
While the seroprevalence of SARS-CoV-2 in healthy people does not differ significantly among age groups, those aged 65 years or older exhibit strikingly higher COVID-19 mortality compared to younger ...individuals. To further understand differing COVID-19 manifestations in patients of different ages, three age groups of ferrets are infected with SARS-CoV-2. Although SARS-CoV-2 is isolated from all ferrets regardless of age, aged ferrets (≥3 years old) show higher viral loads, longer nasal virus shedding, and more severe lung inflammatory cell infiltration, and clinical symptoms compared to juvenile (≤6 months) and young adult (1-2 years) groups. Furthermore, direct contact ferrets co-housed with the virus-infected aged group shed more virus than direct-contact ferrets co-housed with virus-infected juvenile or young adult ferrets. Transcriptome analysis of aged ferret lungs reveals strong enrichment of gene sets related to type I interferon, activated T cells, and M1 macrophage responses, mimicking the gene expression profile of severe COVID-19 patients. Thus, SARS-CoV-2-infected aged ferrets highly recapitulate COVID-19 patients with severe symptoms and are useful for understanding age-associated infection, transmission, and pathogenesis of SARS-CoV-2.
Few studies have used a longitudinal approach to describe the immune response to SARS-CoV-2 infection. Here, we perform single-cell RNA sequencing of bronchoalveolar lavage fluid cells longitudinally ...obtained from SARS-CoV-2-infected ferrets. Landscape analysis of the lung immune microenvironment shows distinct changes in cell proportions and characteristics compared to uninfected control, at 2 and 5 days post-infection (dpi). Macrophages are classified into 10 distinct subpopulations with transcriptome changes among monocyte-derived infiltrating macrophages and differentiated M1/M2 macrophages, notably at 2 dpi. Moreover, trajectory analysis reveals gene expression changes from monocyte-derived infiltrating macrophages toward M1 or M2 macrophages and identifies a macrophage subpopulation that has rapidly undergone SARS-CoV-2-mediated activation of inflammatory responses. Finally, we find that M1 or M2 macrophages show distinct patterns of gene modules downregulated by immune-modulatory drugs. Overall, these results elucidate fundamental aspects of the immune response dynamics provoked by SARS-CoV-2 infection.
The human gut hosts a diverse community of bacteria referred to as the gut microbiome. We investigated the association between the relative abundance of gastric microbiota and gastric cancer (GC) ...risk in a Korean population. The study participants included 268 GC patients and 288 controls. DNA was extracted from gastric biopsies, and 16S rRNA gene analysis was performed. Unconditional logistic regression models were used to observe the associations. Of the participants, those who had the highest level (highest tertile) of relative Helicobacter pylori and Propionibacterium acnes abundances showed a significantly higher risk for GC after adjusting for potential confounding variables (odds ratio (OR) = 1.86, 95% confidence interval (CI) = 1.17-2.97, p for trend = 0.017 and OR = 4.77, 95% CI = 2.94-7.74, p for trend <0.001, respectively). Subjects who carried Prevotella copri had a significantly higher risk of GC than noncarriers (OR = 2.54, 95% CI = 1.42-4.55, p for trend = 0.002). There was a lower risk of GC in subjects carrying Lactococcus lactis than in noncarriers (OR = 0.21, 95% CI = 0.10-0.44, p for trend <0.001). H. pylori, P. acnes and P. copri are strong risk factors, whereas L. lactis is a protective factor, for GC development in Koreans. Further microbiome studies are warranted to verify the findings of the current study.
Patients with early gastric cancers that are limited to gastric mucosa or submucosa usually have an advanced loss of mucosal glandular tissue (glandular atrophy) and are at high risk for subsequent ...(metachronous) development of new gastric cancer. The long-term effects of treatment to eradicate Helicobacter pylori on histologic improvement and the prevention of metachronous gastric cancer remain unclear.
In this prospective, double-blind, placebo-controlled, randomized trial, we assigned 470 patients who had undergone endoscopic resection of early gastric cancer or high-grade adenoma to receive either H. pylori eradication therapy with antibiotics or placebo. Two primary outcomes were the incidence of metachronous gastric cancer detected on endoscopy performed at the 1-year follow-up or later and improvement from baseline in the grade of glandular atrophy in the gastric corpus lesser curvature at the 3-year follow-up.
A total of 396 patients were included in the modified intention-to-treat analysis population (194 in the treatment group and 202 in placebo group). During a median follow-up of 5.9 years, metachronous gastric cancer developed in 14 patients (7.2%) in the treatment group and in 27 patients (13.4%) in the placebo group (hazard ratio in the treatment group, 0.50; 95% confidence interval, 0.26 to 0.94; P=0.03). Among the 327 patients in the subgroup that underwent histologic analysis, improvement from baseline in the atrophy grade at the gastric corpus lesser curvature was observed in 48.4% of the patients in the treatment group and in 15.0% of those in the placebo group (P<0.001). There were no serious adverse events; mild adverse events were more common in the treatment group (42.0% vs. 10.2%, P<0.001).
Patients with early gastric cancer who received H. pylori treatment had lower rates of metachronous gastric cancer and more improvement from baseline in the grade of gastric corpus atrophy than patients who received placebo. (Funded by the National Cancer Center, South Korea; ClinicalTrials.gov number, NCT02407119 .).
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is the cause of a present pandemic, infects human lung alveolar type 2 (hAT2) cells. Characterizing pathogenesis is crucial for ...developing vaccines and therapeutics. However, the lack of models mirroring the cellular physiology and pathology of hAT2 cells limits the study. Here, we develop a feeder-free, long-term, three-dimensional (3D) culture technique for hAT2 cells derived from primary human lung tissue and investigate infection response to SARS-CoV-2. By imaging-based analysis and single-cell transcriptome profiling, we reveal rapid viral replication and the increased expression of interferon-associated genes and proinflammatory genes in infected hAT2 cells, indicating a robust endogenous innate immune response. Further tracing of viral mutations acquired during transmission identifies full infection of individual cells effectively from a single viral entry. Our study provides deep insights into the pathogenesis of SARS-CoV-2 and the application of defined 3D hAT2 cultures as models for respiratory diseases.
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•Long-term 3D culture of primary hAT2 cells in chemically defined conditions•SARS-CoV-2 infects in vitro hAT2 models with substantial ultrastructural changes•Single-cell RNA-seq finds two cellular states of distinct innate immune phenotypes•Mutation analysis reveals single SARS-CoV-2 entry to a hAT2 cell for full infection
To study infection response to SARS-CoV-2, Youk et al. developed a 3D culture model of human alveolar stem cells in chemically defined conditions. They reveal that SARS-CoV-2 productively infects alveolar type 2 cells, resulting in an innate immune response. Full infection of individual cells was exhibited from a single viral entry.
The previous outbreaks of SARS-CoV and MERS-CoV have led researchers to study the role of diagnostics in impediment of further spread and transmission. With the recent emergence of the novel ...SARS-CoV-2, the availability of rapid, sensitive, and reliable diagnostic methods is essential for disease control. Hence, we have developed a reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for the specific detection of SARS-CoV-2. The primer sets for RT-LAMP assay were designed to target the nucleocapsid gene of the viral RNA, and displayed a detection limit of 10
2
RNA copies close to that of qRT-PCR
.
Notably, the assay has exhibited a rapid detection span of 30 min combined with the colorimetric visualization. This test can detect specifically viral RNAs of the SARS-CoV-2 with no cross-reactivity to related coronaviruses, such as HCoV-229E, HCoV-NL63, HCoV-OC43, and MERS-CoV as well as human infectious influenza viruses (type B, H1N1pdm, H3N2, H5N1, H5N6, H5N8, and H7N9), and other respiratory disease-causing viruses (RSVA, RSVB, ADV, PIV, MPV, and HRV). Furthermore, the developed RT-LAMP assay has been evaluated using specimens collected from COVID-19 patients that exhibited high agreement to the qRT-PCR. Our RT-LAMP assay is simple to perform, less expensive, time-efficient, and can be used in clinical laboratories for preliminary detection of SARS-CoV-2 in suspected patients. In addition to the high sensitivity and specificity, this isothermal amplification conjugated with a single-tube colorimetric detection method may contribute to the public health responses and disease control, especially in the areas with limited laboratory capacities.
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