ABSTRACT
We introduce a magnetic bead-based sample preparation scheme for enabling a Raman spectroscopic differentiation of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) positive and negative samples. The beads were functionalized with the angiotensin-converting enzyme 2 (ACE2) receptor protein, which is used as recognition element to selectively enrich SARS-CoV-2 on the surface of the magnetic beads. Subsequent Raman measurements directly enable discriminating SARS-CoV-2 positive and negative samples. The proposed approach is applicable for other virus species, too, when the specific recognition element is exchanged. Series of Raman spectra were measured on three types of samples, namely SARS-CoV-2, Influenza A H1N1 virus and a negative control. For each sample type, eight independent replicates were considered. All spectra are dominated by the magnetic bead substrate and no obvious differences between sample types are apparent. In order to address the subtle differences in the spectra, we calculated different correlation coefficients, namely the Pearson coefficient and the Normalized Cross Correlation coefficient. By comparing the correlation with the negative control differentiating between SARS-CoV-2 and Influenza A virus is possible. This study provides a first step towards the detection and potential classification of different viruses with the use of conventional Raman spectroscopy.
Subject(s)
Coronavirus InfectionsABSTRACT
The SARS-CoV-2 pandemic has had the world in suspense for more than a year. Even if more and more vaccines are approved there is still an urgent need for efficient antiviral treatment strategies. Here, we present data on the inhibitory effect of the local anaesthetic procaine, especially the prodrugs ProcCluster ® and Procaine-hydrochloride on SARS-CoV-2 infection in vitro . Remarkably, similar effects could be shown on the replication of influenza A viruses in cell culture systems. Since the active ingredient procaine is well-tolerated and already used in the clinics for anaesthetic purposes, the further investigation of this substance could enable its reuse in antiviral therapy, including SARS-CoV-2.
Subject(s)
COVID-19ABSTRACT
Background: It is essential to avoid admission of patients with undetected corona virus disease 2019 (COVID-19) to hospitals’ general wards. Even repeated negative reverse transcription polymerase chain reaction (RT-PCR) results do not rule-out COVID-19 with certainty. The study aimed to evaluate a rule-out strategy for COVID-19 using chest computed tomography (CT) in adults being admitted to the emergency department and suspected of COVID-19. Methods: In this prospective, single centre, diagnostic accuracy cohort study, consecutive adults (≥ 18 years) presenting with symptoms consistent with COVID-19 or previous contact to infected individuals, admitted to the emergency department and supposed to be referred to general ward were included in March and April 2020. All participants underwent low-dose chest CT. RT-PCR- and specific antibody tests were used as reference standard. Main outcome measures were sensitivity and specificity of chest CT. Predictive values were calculated based on the theorem of Bayes using Fagan’s nomogram. Results: : Of 165 participants (56.4% male, 71± 16 years) included in the study, the diagnosis of COVID-19 was confirmed with RT-PCR and AB tests in 13 participants (prevalence 7.9%). Sensitivity and specificity of chest CT were 84.6% (95% confidence interval [CI], 54.6-98.1) and 94.7% (95% CI, 89.9-97.7), respectively. Positive and negative likelihood ratio of chest CT were 16.1 (95% CI, 7.9-32.8) and 0.16 (95% CI, 0.05-0.58) and positive and negative predictive value were 57.9% (95% CI, 40.3-73.7) and 98.6% (95% CI, 95.3-99.6), respectively. Conclusion: At a low prevalence of COVID-19, chest CT chest-CT could be used as a complement to repeated RT-PCR testing for early COVID-19 exclusion in adults with suspected infection before referral to hospital’s general wards. Trial registration: ClinicalTrials.gov: NCT04357938 April 22, 2020
Subject(s)
COVID-19ABSTRACT
Infections with SARS-CoV-2 lead to mild to severe coronavirus disease-19 (COVID-19) with systemic symptoms. Although the viral infection originates in the respiratory system, it is unclear how the virus can overcome the alveolar barrier, which is observed in severe COVID-19 disease courses. To elucidate the viral effects on the barrier integrity and immune reactions, we used mono-cell culture systems and a complex human alveolus-on-a-chip model composed of epithelial, endothelial, and mononuclear cells. Our data show that SARS-CoV-2 efficiently infected epithelial cells with high viral loads and inflammatory response, including the interferon expression. By contrast, the adjacent endothelial layer was no infected and did neither show productive virus replication or interferon release. With prolonged infection, both cell types are damaged, and the barrier function is deteriorated, allowing the viral particles to overbear. In our study, we demonstrate that although SARS-CoV-2 is dependent on the epithelium for efficient replication, the neighboring endothelial cells are affected, e.g., by the epithelial cytokine release, which results in the damage of the alveolar barrier function and viral dissemination.
Subject(s)
COVID-19 , Adenocarcinoma, Bronchiolo-AlveolarABSTRACT
Clinical observations indicate that COVID-19 is a systemic disease. An investigation of the viral distribution within the human body in correlation to tissue damage can help understanding the pathophysiology of SARS-CoV-2 infection.We present a detailed mapping of viral RNA in 61 tissues and organs of 11 deceased patients with the diagnosis COVID-19. The autopsies were performed within the (very) early postmortem interval (mean: 5.6 hours) to avoid bias due to viral RNA and tissue degradation. Viral loads, blood levels of cytokines, prothrombotic factors as well as macro- and micro-morphology were correlated.Very high (> 104 copies/ml) viral loads were detected in the lungs of most patients and then correlated to severe tissue damage. Intact viral particles could be verified in the lung tissue by transmission electron microscopy. Viral loads in the lymph nodes were associated with a loss of follicular architecture. Viral RNA was detected throughout further extra-pulmonary tissues and organs without visible tissue damage. Inflammatory cytokines as well as the prothrombotic factors were elevated in all patients.In conclusion, the dissemination of SARS-CoV-2-RNA throughout the body supports the hypothesis of a maladaptive host response with viremia and multi-organ dysfunction.View Full Text