A plasmid DNA-launched SARS-CoV-2 reverse genetics system and coronavirus toolkit for COVID-19 research.

The recent emergence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the underlying cause of Coronavirus Disease 2019 (COVID-19), has led to a worldwide pandemic causing substantial morbidity, mortality, and economic devastation. In response, many laboratories have redirected attention to SARS-CoV-2, meaning there is an urgent need for tools that can be used in laboratories unaccustomed to working with coronaviruses. Here we report a range of tools for SARS-CoV-2 research. First, we describe a facile single plasmid SARS-CoV-2 reverse genetics system that is simple to genetically manipulate and can be used to rescue infectious virus through transient transfection (without in vitro transcription or additional expression plasmids). The rescue system is accompanied by our panel of SARS-CoV-2 antibodies (against nearly every viral protein), SARS-CoV-2 clinical isolates, and SARS-CoV-2 permissive cell lines, which are all openly available to the scientific community. Using these tools, we demonstrate here that the controversial ORF10 protein is expressed in infected cells. Furthermore, we show that the promising repurposed antiviral activity of apilimod is dependent on TMPRSS2 expression. Altogether, our SARS-CoV-2 toolkit, which can be directly accessed via our website at https://mrcppu-covid.bio/, constitutes a resource with considerable potential to advance COVID-19 vaccine design, drug testing, and discovery science.

Shallow water equations for equatorial tsunami waves.

We present derivations of shallow water model equations of Korteweg-de Vries and Boussinesq type for equatorial tsunami waves in the f-plane approximation and discuss their applicability.This article is part of the theme issue 'Nonlinear water waves'.

Spectral stability of periodic waves in the generalized reduced Ostrovsky equation.

We consider stability of periodic travelling waves in the generalized reduced Ostrovsky equation with respect to co-periodic perturbations. Compared to the recent literature, we give a simple argument that proves spectral stability of all smooth periodic travelling waves independent of the nonlinearity power. The argument is based on the energy convexity and does not use coordinate transformations of the reduced Ostrovsky equations to the semi-linear equations of the Klein-Gordon type.

Effects of clobazam for treatment of refractory status epilepticus.

BACKGROUND: Clobazam (CLB) is a well characterized antiepileptic drug (AED) that differs from other benzodiazepines by its basic chemical structure and pharmacodynamic properties. Only one previous study examined the efficacy of CLB as add-on therapy in refractory status epilepticus (RSE). METHODS: We analyzed RSE episodes treated in our institution between 2001 and 2012. Successful treatment with CLB was scored if CLB was the last AED added to therapy before RSE termination. We assessed the differences between patients with and without CLB and correlated CLB with outcome. Among patients treated with CLB, we studied responders and non-responders and compared our CLB cohort with recently published data. RESULTS: CLB was part of the AED regimen in 24/70 (34.3 %) RSE episodes. In six of these (25.0 %) RSE resolution was attributed to CLB. Baseline characteristics of episodes with and without CLB treatment showed no significant differences and RSE termination rates were very similar (83.3 % vs. 80.4 %). CLB was administered in clinically more complex RSE with longer RSE duration and worse outcome, but CLB was not related independently to outcome. Comparison of our results with previously published data revealed that baseline characteristics as well as CLB maintenance doses and time of treatment initiation were similar in both cohorts. CLB was less frequently the last AED added to RSE therapy in our patients indicating a lower treatment success rate than previously reported. CONCLUSIONS: CLB represents a reasonable AED and promising add-on agent for treatment of RSE. However, rates of successful CLB response were substantially lower than in a recently published study. Differing RSE characteristics and treatment strategies may account for the discrepancy between study results, as RSE etiologies and seizures types associated with unfavorable prognosis were more common in our cohort, while anesthetics tended to be less frequently applied to achieve seizure control.

Association of seizure duration and outcome in refractory status epilepticus.

The aim of the study was to identify factors influencing long-term outcome and to evaluate the prognostic power of the Status Epilepticus Severity Score (STESS) in refractory status epilepticus (RSE). We retrospectively extracted data on baseline characteristics, RSE details, and hospital course including complications from all patients treated for RSE in our institution between January 2001 and January 2013. Functional outcome was assessed using the modified Rankin Scale (mRS) and was defined as good when either RSE did not lead to functional decline or when the resulting mRS score was 2 or below. Seventy-one episodes in 65 patients were analyzed. The median follow-up time was 12 weeks (IQR 6-35), two patients were lost to follow-up. Poor functional long-term outcome was observed in 42/69 (60.9%) episodes. In-hospital mortality occurred in 13/71 (18.3%) episodes. Multivariable analysis revealed that STESS ≥ 3, longer RSE duration, and sepsis were independently related to poor functional long-term outcome. Receiver operating characteristics (ROC) curve analyses confirmed the cut-off dichotomization into STESS ≥ 3 and STESS < 3 for optimal discrimination between good and poor outcome (AUC = 0.671, p = 0.002, YI = 0.368, NPV = 0.607, PPV = 0.756) and revealed an RSE duration of 10 days as a significant cut-off point associated with outcome (AUC = 0.712, p = 0.012, YI = 0.310; NPV = 0.545, PPV = 0.750). In conclusion, STESS and RSE duration represent relevant scores and parameters impacting long-term outcome after RSE. A shorter RSE duration is associated with better outcome and, therefore, rapid and adequate treatment for seizure termination should be enforced.

Traveling surface waves of moderate amplitude in shallow water.

We study traveling wave solutions of an equation for surface waves of moderate amplitude arising as a shallow water approximation of the Euler equations for inviscid, incompressible and homogeneous fluids. We obtain solitary waves of elevation and depression, including a family of solitary waves with compact support, where the amplitude may increase or decrease with respect to the wave speed. Our approach is based on techniques from dynamical systems and relies on a reformulation of the evolution equation as an autonomous Hamiltonian system which facilitates an explicit expression for bounded orbits in the phase plane to establish existence of the corresponding periodic and solitary traveling wave solutions.