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Background Coronavirus disease 2019 (COVID-19) is a respiratory disease associated with thrombotic outcomes with coagulation and endothelial disorders. Based on that, several anticoagulation guidelines have been proposed. We aimed to determine whether anticoagulation therapy modifies the risk of developing severe COVID-19. Methods and Results Patients with COVID-19 initially admitted in medical wards of 24 French hospitals were included prospectively from February 26 to April 20, 2020. We used a Poisson regression model, Cox proportional hazard model, and matched propensity score to assess the effect of anticoagulation on outcomes (intensive care unit admission or in-hospital mortality). The study enrolled 2878 patients with COVID-19, among whom 382 (13.2%) were treated with oral anticoagulation therapy before hospitalization. After adjustment, anticoagulation therapy before hospitalization was associated with a better prognosis with an adjusted hazard ratio of 0.70 (95% CI, 0.55-0.88). Analyses performed using propensity score matching confirmed that anticoagulation therapy before hospitalization was associated with a better prognosis, with an adjusted hazard ratio of 0.43 (95% CI, 0.29-0.63) for intensive care unit admission and adjusted hazard ratio of 0.76 (95% CI, 0.61-0.98) for composite criteria intensive care unit admission or death. In contrast, therapeutic or prophylactic low- or high-dose anticoagulation started during hospitalization were not associated with any of the outcomes. Conclusions Anticoagulation therapy used before hospitalization in medical wards was associated with a better prognosis in contrast with anticoagulation initiated during hospitalization. Anticoagulation therapy introduced in early disease could better prevent COVID-19-associated coagulopathy and endotheliopathy, and lead to a better prognosis.

Purpose: Medical education videos can enhance learning and easily integrate into common instructional methods. YouTube permits worldwide access to high-quality medical education videos; however, no studies have described the reach of medical education videos on YouTube or what topics are preferred., Method: One year of YouTube analytics data (February 1, 2016, to January 31, 2017) was collected for a medical-education-focused channel called Osmosis. Created December 20, 2015, the channel had 189 disease-focused videos by January 2017. Viewer and subscriber data were analyzed according to the World Bank's four income and seven region classifications. Topic viewing was analyzed according to income level., Results: The channel had accumulated 105,117 subscribers and 5,226,405 views for 20,153,093 minutes (38.3 years) from viewers located in 213/218 (97.7%) World Bank economies. While the number of videos increased 4.8-fold from February 2016 to January 2017, monthly views increased 50-fold and subscribers increased 117-fold. Low- or middle-income countries generated 2.2 million (42%) views and 52,942 (50%) subscribers, with similar view proportions across income level during the 12 months. A plurality of views (1.5 million; 29%) came from North America; Sub-Saharan Africa had the lowest number (150,065; 2.9%). Topic viewing generally corresponded to population health statistics., Conclusions: Medical education content on YouTube can immediately and consistently reach a global viewership with relevant content. Educators may consider posting videos to YouTube to reach a broad audience. Future work should seek to optimize assessment of learning and investigate how videos may affect patients.

The homotetrameric Escherichia coli single-stranded DNA binding protein (SSB) plays a central role in DNA replication, repair and recombination. E. coli SSB can bind to long single-stranded DNA (ssDNA) in multiple binding modes using all four subunits [(SSB)65 mode] or only two subunits [(SSB)35 binding mode], with the binding mode preference regulated by salt concentration and SSB binding density. These binding modes display very different ssDNA binding properties with the (SSB)35 mode displaying highly cooperative binding to ssDNA. SSB tetramers also bind an array of partner proteins, recruiting them to their sites of action. This is achieved through interactions with the last 9 amino acids (acidic tip) of the intrinsically disordered linkers (IDLs) within the four C-terminal tails connected to the ssDNA binding domains. Here, we show that the amino acid composition and length of the IDL affects the ssDNA binding mode preferences of SSB protein. Surprisingly, the number of IDLs and the lengths of individual IDLs together with the acidic tip contribute to highly cooperative binding in the (SSB)35 binding mode. Hydrodynamic studies and atomistic simulations suggest that the E. coli SSB IDLs show a preference for forming an ensemble of globular conformations, whereas the IDL from Plasmodium falciparum SSB forms an ensemble of more extended random coils. The more globular conformations correlate with cooperative binding., (Copyright © 2015 Elsevier Ltd. All rights reserved.)