Bunyaviridae RNA Polymerases (L-Protein) Have an N-Terminal, Influenza-Like Endonuclease Domain, Essential for Viral Cap-Dependent Transcription

Bunyaviruses are a large family of segmented RNA viruses which, like influenza virus, use a cap-snatching mechanism for transcription whereby short capped primers derived by endonucleolytic cleavage of host mRNAs are used by the viral RNA-dependent RNA polymerase (L-protein) to transcribe viral mRNAs. It was recently shown that the cap-snatching endonuclease of influenza virus resides in a discrete N-terminal domain of the PA polymerase subunit. Here we structurally and functionally characterize a similar endonuclease in La Crosse orthobunyavirus (LACV) L-protein. We expressed N-terminal fragments of the LACV L-protein and found that residues 1-180 have metal binding and divalent cation dependent nuclease activity analogous to that of influenza virus endonuclease. The 2.2 Å resolution X-ray crystal structure of the domain confirms that LACV and influenza endonucleases have similar overall folds and identical two metal binding active sites. The in vitro activity of the LACV endonuclease could be abolished by point mutations in the active site or by binding 2,4-dioxo-4-phenylbutanoic acid (DPBA), a known influenza virus endonuclease inhibitor. A crystal structure with bound DPBA shows the inhibitor chelating two active site manganese ions. The essential role of this endonuclease in cap-dependent transcription was demonstrated by the loss of transcriptional activity in a RNP reconstitution system in cells upon making the same point mutations in the context of the full-length LACV L-protein. Using structure based sequence alignments we show that a similar endonuclease almost certainly exists at the N-terminus of L-proteins or PA polymerase subunits of essentially all known negative strand and cap-snatching segmented RNA viruses including arenaviruses (2 segments), bunyaviruses (3 segments), tenuiviruses (4–6 segments), and orthomyxoviruses (6–8 segments). This correspondence, together with the well-known mapping of the conserved polymerase motifs to the central regions of the L-protein and influenza PB1 subunit, suggests that L-proteins might be architecturally, and functionally equivalent to a concatemer of the three orthomyxovirus polymerase subunits in the order PA-PB1-PB2. Furthermore, our structure of a known influenza endonuclease inhibitor bound to LACV endonuclease suggests that compounds targeting a potentially broad spectrum of segmented RNA viruses, several of which are serious or emerging human, animal and plant pathogens, could be developed using structure-based optimisation

Evaluation of young smokers and non-smokers with Electrogustometry and Contact Endoscopy

<p>Abstract</p> <p>Background</p> <p>Smoking is the cause of inducing changes in taste functionality under conditions of chronic exposure. The objective of this study was to evaluate taste sensitivity in young smokers and non-smokers and identify any differences in the shape, density and vascularisation of the fungiform papillae (fPap) of their tongue.</p> <p>Methods</p> <p>Sixty-two male subjects who served in the Greek military forces were randomly chosen for this study. Thirty-four were non-smokers and 28 smokers. Smokers were chosen on the basis of their habit to hold the cigarette at the centre of their lips. Taste thresholds were measured with Electrogustometry (EGM). The morphology and density of the fungiform papillae (fPap) at the tip of the tongue were examined with Contact Endoscopy (CE).</p> <p>Results</p> <p>There was found statistically important difference (<it>p </it>< 0.05) between the taste thresholds of the two groups although not all smokers presented with elevated taste thresholds: Six of them (21%) had taste thresholds similar to those of non-smokers. Differences concerning the shape and the vessels of the fungiform papillae between the groups were also detected. Fewer and flatter fPap were found in 22 smokers (79%).</p> <p>Conclusion</p> <p>The majority of smokers shown elevated taste thresholds in comparison to non-smokers. Smoking is an important factor which can lead to decreased taste sensitivity. The combination of methods, such as EGM and CE, can provide useful information about the vascularisation of taste buds and their functional ability.</p

Efficacy of the mRNA-1273 SARS-CoV-2 vaccine at completion of blinded phase

BACKGROUND At interim analysis in a phase 3, observer-blinded, placebo-controlled clinical trial, the mRNA-1273 vaccine showed 94.1% efficacy in preventing coronavirus disease 2019 (Covid-19). After emergency use of the vaccine was authorized, the protocol was amended to include an open-label phase. Final analyses of efficacy and safety data from the blinded phase of the trial are reported. METHODS We enrolled volunteers who were at high risk for Covid-19 or its complications; participants were randomly assigned in a 1:1 ratio to receive two intramuscular injections of mRNA-1273 (100 μg) or placebo, 28 days apart, at 99 centers across the United States. The primary end point was prevention of Covid-19 illness with onset at least 14 days after the second injection in participants who had not previously been infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The data cutoff date was March 26, 2021. RESULTS The trial enrolled 30,415 participants; 15,209 were assigned to receive the mRNA-1273 vaccine, and 15,206 to receive placebo. More than 96% of participants received both injections, 2.3% had evidence of SARS-CoV-2 infection at baseline, and the median follow-up was 5.3 months in the blinded phase. Vaccine efficacy in preventing Covid-19 illness was 93.2% (95% confidence interval [CI], 91.0 to 94.8), with 55 confirmed cases in the mRNA-1273 group (9.6 per 1000 person-years; 95% CI, 7.2 to 12.5) and 744 in the placebo group (136.6 per 1000 person-years; 95% CI, 127.0 to 146.8). The efficacy in preventing severe disease was 98.2% (95% CI, 92.8 to 99.6), with 2 cases in the mRNA-1273 group and 106 in the placebo group, and the efficacy in preventing asymptomatic infection starting 14 days after the second injection was 63.0% (95% CI, 56.6 to 68.5), with 214 cases in the mRNA-1273 group and 498 in the placebo group. Vaccine efficacy was consistent across ethnic and racial groups, age groups, and participants with coexisting conditions. No safety concerns were identified. CONCLUSIONS The mRNA-1273 vaccine continued to be efficacious in preventing Covid-19 illness and severe disease at more than 5 months, with an acceptable safety profile, and protection against asymptomatic infection was observed

Minimal Length Scale Scenarios for Quantum Gravity

We review the question of whether the fundamental laws of nature limit our ability to probe arbitrarily short distances. First, we examine what insights can be gained from thought experiments for probes of shortest distances, and summarize what can be learned from different approaches to a theory of quantum gravity. Then we discuss some models that have been developed to implement a minimal length scale in quantum mechanics and quantum field theory. These models have entered the literature as the generalized uncertainty principle or the modified dispersion relation, and have allowed the study of the effects of a minimal length scale in quantum mechanics, quantum electrodynamics, thermodynamics, black-hole physics and cosmology. Finally, we touch upon the question of ways to circumvent the manifestation of a minimal length scale in short-distance physics.Comment: Published version available at http://www.livingreviews.org/lrr-2013-

Beyond equilibrium climate sensitivity

ISSN:1752-0908ISSN:1752-089

Limitations of real-world treatment with atorvastatin monotherapy for lowering LDL-C in high-risk cardiovascular patients in the US

Elizabeth Marrett,1 Changgeng Zhao,1 Ning Jackie Zhang,2 Qiaoyi Zhang,1 Dena R Ramey,1 Joanne E Tomassini,1 Andrew M Tershakovec,1 David R Neff11Merck &amp; Co, Inc., Whitehouse Station, NJ, USA; 2College of Health and Public Affairs, University of Central Florida, Orlando, FL, USABackground: Guidelines endorse statin therapy for lowering low-density lipoprotein cholesterol (LDL-C) to recommended levels, in patients with cardiovascular disease (CVD) risk, if needed, after lifestyle changes. Atorvastatin is a common statin with greater LDL-C lowering efficacy than most other statins; its availability in generic form will likely increase its use. This study assessed attainment of guideline-recommended LDL-C levels in high-risk CVD patients treated with atorvastatin monotherapy.Methods: Analyses of two retrospective US cohorts of patients who received a prescription for atorvastatin monotherapy between January 1, 2008 and December 31, 2010 (index date defined as first prescription date) in the GE Centricity Electronic Medical Record (EMR) (N=10,693) and Humana Medicare (N=16,798) databases. Eligible patients were &ge;18 years, diagnosed with coronary heart disease or atherosclerotic vascular disease, with &ge;1 LDL-C measurement between 3 months and 1 year postindex date, and continuously enrolled for 1 year prior to and following the index date.Results: Of the eligible patients, 21.8%, 29.6%, 29.9%, and 18.7% (GE Centricity EMR) and 25.4%, 32.9%, 27.8%, and 14.0% (Humana Medicare) received 10, 20, 40, and 80 mg doses of atorvastatin, respectively. The mean &plusmn; standard deviation (SD) follow-up LDL-C levels were 2.1&plusmn;0.8 mmol/L (83&plusmn;30 mg/dL) and 2.3&plusmn;0.8 mmol/L (88&plusmn;31 mg/dL) for the GE Centricity EMR and Humana Medicare cohorts, respectively. Regardless of dose, only 28.3%-34.8% of patients had LDL-C levels &lt;1.8 mmol/L (&lt;70 mg/dL), and 72.0%-78.0% achieved LDL-C &lt;2.6 mmol/L (&lt;100 mg/dL) in both cohorts. As many as 41% and 13% of patients had LDL-C levels &ge;0.5 mmol/L (&ge;20 mg/dL) above LDL-C 1.8 mmol/L (70 mg/dL) and 2.6 mmol/L (100 mg/dL), respectively, in both cohorts; these percentages were generally similar across atorvastatin doses.Conclusion: In this real-world US setting, a large number of high-risk CVD patients did not attain guideline-recommended LDL-C levels with atorvastatin monotherapy. More than 65% of the patients had LDL-C levels &gt;1.8 mmol/L (&gt;70 mg/dL), and of these, 30%-40% had LDL-C levels &ge;0.5 mmol/L (&ge;20 mg/dL) above this, regardless of dose. This suggests that more effective lipid-lowering strategies, such as statin uptitration, switching to a higher efficacy statin, and/or combination therapy, may be required to achieve optimal LDL-C lowering in high-risk patients.Keywords: statin therapy, managed-care, lipid-lowering therap

Changes in LDL-C levels and goal attainment associated with addition of ezetimibe to simvastatin, atorvastatin, or rosuvastatin compared with titrating statin monotherapy

JoAnne M Foody,1 Peter P Toth,2 Joanne E Tomassini,3 Shiva Sajjan,3 Dena R Ramey,3 David Neff,3 Andrew M Tershakovec,3 Henry Hu,3 Kaan Tunceli31Brigham and Women&#39;s Hospital, Boston, MA, 2CGH Medical Center, Sterling, IL, and University of Illinois College of Medicine, Peoria, IL, 3Merck &amp; Co., Inc., Whitehouse Station, NJ, USABackground: Many high-risk coronary heart disease (CHD) patients on statin monotherapy do not achieve guideline-recommended low-density lipoprotein cholesterol (LDL-C) goals, and combination lipid-lowering therapy may be considered for these individuals. The effect of adding ezetimibe to simvastatin, atorvastatin, or rosuvastatin therapy versus titrating these statins on LDL-C changes and goal attainment in CHD or CHD risk-equivalent patients was assessed in a large, managed-care database in the US.Methods: Eligible patients (n = 17,830), initially on statin monotherapy who were &ge;18 years with baseline and follow-up LDL-C values, no concomitant use of other lipid-lowering therapy, and on lipid-lowering therapy for &ge;42 days, were identified between November 1, 2002 and September 30, 2009. The percent change from baseline in LDL-C levels and the odds ratios for attainment of LDL-C <1.8 and <2.6 mmol/L (70 and 100 mg/dL) were estimated using an analysis of covariance and logistic regression, respectively, adjusted for various baseline factors.Results: LDL-C reductions from baseline and goal attainment improved substantially in patients treated with ezetimibe added onto simvastatin, atorvastatin, or rosuvastatin therapy (n = 2,312) versus those (n = 13,053) who titrated these statins. In multivariable models, percent change from baseline in LDL-C was -13.1% to -14.8% greater for those who added ezetimibe onto simvastatin, atorvastatin, or rosuvastatin versus those who titrated. The odds of attaining LDL-C <1.8 and <2.6 mmol/L (70 and 100 mg/dL) increased by 2.6&ndash;3.2-fold and 2.5&ndash;3.1-fold, respectively, in patients who added ezetimibe onto simvastatin, atorvastatin, or rosuvastatin versus titrating statins.Conclusion: CHD/CHD risk-equivalent patients in a large US managed-care database, who added ezetimibe onto simvastatin, atorvastatin, or rosuvastatin, had greater LDL-C reductions and goal attainment than those who uptitrated these statin therapies. Our study suggests that high-risk CHD patients in need of more intensive LDL-C lowering therapy may benefit by adding ezetimibe onto statin therapy.Keywords: low-density lipoprotein cholesterol goal, ezetimibe, atorvastatin, rosuvastati