Structure and Function Analysis of an Antibody Recognizing All Influenza A Subtypes.

Influenza virus remains a threat because of its ability to evade vaccine-induced immune responses due to antigenic drift. Here, we describe the isolation, evolution, and structure of a broad-spectrum human monoclonal antibody (mAb), MEDI8852, effectively reacting with all influenza A hemagglutinin (HA) subtypes. MEDI8852 uses the heavy-chain VH6-1 gene and has higher potency and breadth when compared to other anti-stem antibodies. MEDI8852 is effective in mice and ferrets with a therapeutic window superior to that of oseltamivir. Crystallographic analysis of Fab alone or in complex with H5 or H7 HA proteins reveals that MEDI8852 binds through a coordinated movement of CDRs to a highly conserved epitope encompassing a hydrophobic groove in the fusion domain and a large portion of the fusion peptide, distinguishing it from other structurally characterized cross-reactive antibodies. The unprecedented breadth and potency of neutralization by MEDI8852 support its development as immunotherapy for influenza virus-infected humans.

Association between First-pass Intubation Success and Enhanced PPE Use during the COVID-19 Pandemic.

OBJECTIVES: We evaluated first-pass endotracheal intubation (ETI) success within the critical care transport (CCT) environment using a natural experiment created by the COVID-19 pandemic. Our primary objective was to evaluate if the use of personal protective equipment (PPE) or the COVID-19 time period was associated with differences in first-pass success rates of ETI within a large CCT system with a high baseline ETI first-pass success rate. We hypothesized that pandemic-related challenges would be associated with decreased first-pass success rates. METHODS: We performed a retrospective before-after cohort study of airway management by CCT personnel relative to the COVID-19 pandemic. We used a mixed effects logistic regression to evaluate the association between enhanced PPE (N95 mask, eye protection) use and the pandemic time period on first-pass intubation success, while controlling for other factors potentially associated with intubation success. Variables in the final model included patient demographics (age, sex, and race), body mass index, medical category (trauma versus non-trauma), interfacility or scene response, blade size (Macintosh 3 versus 4), use of face mask, use of eye protection, and crew member length of service. RESULTS: We identified 1279 cases involving intubation attempts on adult patients during the study period. A total of 1133 cases were included in the final analysis, with an overall first-pass success rate of 95.7% (96.4% pre-COVID-19 and 94.8% during COVID-19). In our final mixed effects logistic regression model, enhanced PPE use and the COVID-19 time period were not associated with first-pass intubation success rate. CONCLUSION: In a large regional CCT system with a high ETI first-pass success rate, neither PPE use nor the COVID-19 time period were associated with differences in ETI first-pass success while controlling for relevant patient and operational factors. Other emergency medical services (EMS) systems may have encountered different effects of pandemic-related PPE use on intubation success rates. Further studies are needed to evaluate the influence of sustained use of enhanced PPE or changes in training or procedural experience on post-pandemic ETI first-pass success rates for non-CCT EMS clinicians.

Characterizing Air Medical Transport Experiences in Emergency Medicine Residency Training Programs.

OBJECTIVE: Air medical transportation (AMT) of patients plays a critical role in the prehospital care of the ill patient. Despite its importance, there is no requirement in emergency medicine training programs to have direct experience or education on the topic, and data detailing current AMT experiences across programs are limited. METHODS: A survey detailing program characteristics, AMT experience characteristics, and curriculum factors relating to AMT experience was sent to all 275 credentialed emergency medicine residency training programs in the United States. Our outcomes were to describe the characteristics of AMT and non-AMT programs (proportions) and to evaluate associations (odds ratios with 95% confidence intervals) between program characteristics and 1) AMT experience opportunity and 2) level of resident participation among AMT programs. RESULTS: Two hundred (73%) programs responded, with 135 of 200 (68%) offering some type of AMT experience. The majority of programs offering AMT were 3 years (113 [84%]), university based (63 [47%]), and located in small urban areas (57 [42%]). When AMT was offered, most programs reported that the overall resident participation was low (≤ 20%). Programs that did not offer shift reduction or additional pay for participation in AMT were significantly more likely to have low participation than those with incentives (odds ratio = 4.8; 95% confidence interval, 1.8-15.3). Around one third of AMT experiences allowed for direct patient care. Less than half of the responding programs reported a dedicated AMT curriculum. CONCLUSION: The majority of emergency medicine residency training programs offer an AMT experience, but this experience is highly variable, and overall participation by residents is low. Given the importance of AMT in the care of emergency patients, standardization and increased access to AMT experience and education should be considered by emergency medicine training programs moving forward.

Balancing food acquisition and predation risk drives demographic changes in snowshoe hare population cycles.

Snowshoe hare cycles are one of the most prominent phenomena in ecology. Experimental studies point to predation as the dominant driving factor, but previous experiments combining food supplementation and predator removal produced unexplained multiplicative effects on density. We examined the potential interactive effects of food limitation and predation in causing hare cycles using an individual-based food-supplementation experiment over-winter across three cycle phases that naturally varied in predation risk. Supplementation doubled over-winter survival with the largest effects occurring in the late increase phase. Although the proximate cause of mortality was predation, supplemented hares significantly decreased foraging time and selected for conifer habitat, potentially reducing their predation risk. Supplemented hares also lost less body mass which resulted in the production of larger leverets. Our results establish a mechanistic link between how foraging time, mass loss and predation risk affect survival and reproduction, potentially driving demographic changes associated with hare cycles.

Tissue-specific mRNA profiling of the Brassica napus-Sclerotinia sclerotiorum interaction uncovers novel regulators of plant immunity.

White mold is caused by the fungal pathogen Sclerotinia sclerotiorum and leads to rapid and significant loss in plant yield. Among its many brassicaceous hosts, including Brassica napus (canola) and Arabidopsis, the response of individual tissue layers directly at the site of infection has yet to be explored. Using laser microdissection coupled with RNA sequencing, we profiled the epidermis, mesophyll, and vascular leaf tissue layers of B. napus in response to S. sclerotiorum. High-throughput tissue-specific mRNA sequencing increased the total number of detected transcripts compared with whole-leaf assessments and provided novel insight into the conserved and specific roles of ontogenetically distinct leaf tissue layers in response to infection. When subjected to pathogen infection, the epidermis, mesophyll, and vasculature activate both specific and shared gene sets. Putative defense genes identified through transcription factor network analysis were then screened for susceptibility against necrotrophic, hemi-biotrophic, and biotrophic pathogens. Arabidopsis deficient in PR5-like RECEPTOR KINASE (PR5K) mRNA levels were universally susceptible to all pathogens tested and were further characterized to identify putative interacting partners involved in the PR5K signaling pathway. Together, these data provide insight into the complexity of the plant defense response directly at the site of infection.

Efficacy of virtual and asynchronous teaching of computer-assisted diagnosis of genetic diseases seen in clinics.

We studied if clinicians could gain sufficient working knowledge of a computer-assisted diagnostic decision support system (DDSS) (SimulConsult), to make differential diagnoses (DDx) of genetic disorders. We hypothesized that virtual training could be convenient, asynchronous, and effective in teaching clinicians how to use a DDSS. We determined the efficacy of virtual, asynchronous teaching for clinicians to gain working knowledge to make computer-assisted DDx. Our study consisted of three surveys (Baseline, Training, and After Use) and a series of case problems sent to clinicians at Vanderbilt University Medical Center. All participants were able to generate computer-assisted DDx that achieved passing scores of the case problems. Between 75% and 92% agreed/completely agreed the DDSS was useful to their work and for clinical decision support and was easy to use. Participants' use of the DDSS resulted in statistically significant time savings in key tasks and in total time spent on clinical tasks. Our results indicate that virtual, asynchronous teaching can be an effective format to gain a working knowledge of a DDSS, and its clinical use could result in significant time savings across multiple tasks as well as facilitate synergistic interaction between clinicians and lab specialists. This approach is especially pertinent and offers value amid the COVID-19 pandemic.

Treatment of Malignant Hyperthermia During Interfacility Transport of a Patient With Methamphetamine Toxicity.

Malignant hyperthermia (MH) is a rare disorder that leads to a hypermetabolic response; if unrecognized, it can quickly lead to serious morbidity and mortality. It is imperative that critical care transport providers are able to recognize and initiate treatment for MH. A 33-year-old man presented to the emergency department with seizures and altered mental status after ingesting methamphetamine. The patient was intubated in the emergency department with succinylcholine and propofol. After intubation, the patient became tetanic, hyperthermic, and hypercarbic. Given the concern for MH, the patient was treated with dantrolene and transported by helicopter air ambulance to the affiliated quaternary care center where he progressed to multiorgan failure and died. MH is a genetic disorder that manifests after exposure to certain stimuli, most notably inhaled anesthetics and succinylcholine. The hypermetabolic response is triggered by unregulated release of intracellular calcium secondary to a dysfunctional calcium channel. MH is often diagnosed clinically. Early clinical manifestations of MH include an increase in end-tidal carbon dioxide, tachycardia, muscle rigidity, and hyperthermia. For prehospital clinicians, the most likely offending agent is succinylcholine. The pharmacologic treatment of MH is dantrolene. Prompt recognition and treatment of MH can decrease morbidity and mortality.

The library's role in countering infodemics.

Internet and communication technologies enable the creation of tremendous amounts of textual, graphic, and pictorial information. User-generated content published through personal web pages, blogs, and social media platforms has not only increased the amount of information available, but also expanded its reach. However, this ubiquity of information and empowerment of its creators leads to potentially controversial, futile, and inaccurate content circulating throughout the world. In the case of the COVID-19 pandemic, this can create false hope, fear, anxiety, harm, and confusion amongst information stakeholders. The World Health Organization recently applied the term "infodemic" to the COVID-19 pandemic. This commentary briefly discusses the current infodemic, its potential consequences, and the role of libraries-specifically health sciences, biomedical, and medical libraries-to help counter the COVID-19 infodemic. The discussion also has relevance for infodemics relating to other health and non-health affairs.

The Never-Ending Evolutionary Saga of Assessing and Demonstrating the Value of Information Services in a Biomedical Library.

Demonstrating added value can be very challenging, yet it is becoming important in academic libraries. The current literature primarily discusses citation analysis and usage reports to demonstrate return on investment for collections or impact on scholarly activity. However, value is not only in our collections but also in the library staff who support the institutional mission. Vanderbilt University's Annette and Irwin Eskind Family Biomedical Library and Learning Center has been experimenting with several methods to supplement the collections data with services performed by the staff. This article discusses the project's four phases as part of the goal to strategically demonstrate the biomedical library's added value to the university and medical center.

Structural basis of lentiviral subversion of a cellular protein degradation pathway.

Lentiviruses contain accessory genes that have evolved to counteract the effects of host cellular defence proteins that inhibit productive infection. One such restriction factor, SAMHD1, inhibits human immunodeficiency virus (HIV)-1 infection of myeloid-lineage cells as well as resting CD4(+) T cells by reducing the cellular deoxynucleoside 5'-triphosphate (dNTP) concentration to a level at which the viral reverse transcriptase cannot function. In other lentiviruses, including HIV-2 and related simian immunodeficiency viruses (SIVs), SAMHD1 restriction is overcome by the action of viral accessory protein x (Vpx) or the related viral protein r (Vpr) that target and recruit SAMHD1 for proteasomal degradation. The molecular mechanism by which these viral proteins are able to usurp the host cell's ubiquitination machinery to destroy the cell's protection against these viruses has not been defined. Here we present the crystal structure of a ternary complex of Vpx with the human E3 ligase substrate adaptor DCAF1 and the carboxy-terminal region of human SAMHD1. Vpx is made up of a three-helical bundle stabilized by a zinc finger motif, and wraps tightly around the disc-shaped DCAF1 molecule to present a new molecular surface. This adapted surface is then able to recruit SAMHD1 via its C terminus, making it a competent substrate for the E3 ligase to mark for proteasomal degradation. The structure reported here provides a molecular description of how a lentiviral accessory protein is able to subvert the cell's normal protein degradation pathway to inactivate the cellular viral defence system.

Receptor binding by H10 influenza viruses.

H10N8 follows H7N9 and H5N1 as the latest in a line of avian influenza viruses that cause serious disease in humans and have become a threat to public health. Since December 2013, three human cases of H10N8 infection have been reported, two of whom are known to have died. To gather evidence relating to the epidemic potential of H10 we have determined the structure of the haemagglutinin of a previously isolated avian H10 virus and we present here results relating especially to its receptor-binding properties, as these are likely to be major determinants of virus transmissibility. Our results show, first, that the H10 virus possesses high avidity for human receptors and second, from the crystal structure of the complex formed by avian H10 haemagglutinin with human receptor, it is clear that the conformation of the bound receptor has characteristics of both the 1918 H1N1 pandemic virus and the human H7 viruses isolated from patients in 2013 (ref. 3). We conclude that avian H10N8 virus has sufficient avidity for human receptors to account for its infection of humans but that its preference for avian receptors should make avian-receptor-rich human airway mucins an effective block to widespread infection. In terms of surveillance, particular attention will be paid to the detection of mutations in the receptor-binding site of the H10 haemagglutinin that decrease its avidity for avian receptor, and could enable it to be more readily transmitted between humans.

Epsom Salt Ingestion Leading to Severe Hypermagnesemia Necessitating Dialysis.

BACKGROUND: Hypermagnesemia is an often overlooked electrolyte abnormality that has a myriad of presenting symptoms. It has been observed after both accidental and intentional ingestions of magnesium-containing compounds, and as in the case presented, Epsom salts, which are primarily magnesium sulfate. CASE REPORT: A 56-year-old man presented to the emergency department reporting weakness after an ingestion of Epsom salts used as a laxative and was found to be bradycardic and hypotensive. He subsequently developed altered mental status and respiratory depression necessitating intubation. His magnesium level was found to be > 3.91 mmol/L (> 9.5 mg/dL). He was given multiple doses of calcium gluconate and generous i.v. fluids with furosemide, with minimal improvement. However, his magnesium level corrected rapidly after initiation of dialysis, and 3 days later he was discharged home in good condition with normal neurologic function. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Keeping a high level of suspicion for, and quickly recognizing, hypermagnesemia allows for prompt initiation of treatment, which can avoid significant hemodynamic or respiratory compromise. Mainstays of treatment are i.v. calcium and i.v. fluids. Loop diuretics may be given as an adjunct as well. Dialysis should be considered in cases of severe hypermagnesemia because it results in rapid correction of magnesium levels.

Transcriptome Analysis of Rlm2-Mediated Host Immunity in the Brassica napus-Leptosphaeria maculans Pathosystem.

Our study investigated disease resistance in the Brassica napus-Leptosphaeria maculans pathosystem using a combination of laser microdissection, dual RNA sequencing, and physiological validations of large-scale gene sets. The use of laser microdissection improved pathogen detection and identified putative L. maculans effectors and lytic enzymes operative during host colonization. Within 24 h of inoculation, we detected large shifts in gene activity in resistant cotyledons associated with jasmonic acid and calcium signaling pathways that accelerated the plant defense response. Sequencing data were validated through the direct quantification of endogenous jasmonic acid levels. Additionally, resistance against L. maculans was abolished when the calcium chelator EGTA was applied to the inoculation site, providing physiological evidence of the role of calcium in B. napus immunity against L. maculans. We integrated gene expression data with all available information on cis-regulatory elements and transcription factor binding affinities to better understand the gene regulatory networks underpinning plant resistance to hemibiotrophic pathogens. These in silico analyses point to early cellular reprogramming during host immunity that are coordinated by CAMTA, BZIP, and bHLH transcription factors. Together, we provide compelling genetic and physiological evidence into the programming of plant resistance against fungal pathogens.

Forecasting aortic aneurysm rupture: A systematic review of seasonal and atmospheric associations.

BACKGROUND: Abdominal aortic aneurysms (AAAs) represent a significant burden of disease worldwide, and their rupture, without treatment, has an invariably high mortality rate. Whereas some risk factors for ruptured AAAs (rAAAs) are well established, such as hypertension, smoking, and female sex, the impact of seasonal and meteorologic variables is less clear. We systematically reviewed the literature to determine whether these variables are associated with rAAA. METHODS: Review methods were according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We calculated pooled proportions and incidence rate ratios (IRRs) for the different months and seasons. Funnel plots were constructed to assess for publication bias. Given the poor methodologic quality of included studies, a sensitivity analysis was performed on better-quality studies, which scored 6 and above of 9 in the author-modified Newcastle-Ottawa Scale. RESULTS: The pooled proportion of rAAA was highest in the autumn season (incidence rate, 26.6%; 95% confidence interval [CI], 25.6%-27.7%; I2 = 15.4%), followed by winter (incidence rate, 26.2%; 95% CI, 24.1%-28.2%; I2 = 72.4%), and lowest in summer (incidence rate, 21.1%; 95% CI, 19.3%-23.0%; I2 = 70.4%). The IRRs of rAAA were -6.9% (95% CI, -9.8% to -3.9%), -19.5% (95% CI, -22% to -16.8%), +10.5% (95% CI, 7.2%-13.9%), and +18.1% (95% CI, 15%-22%) in spring, summer, autumn, and winter compared with the remaining seasons, respectively (all P < .0001), thus affirming existence of seasonal variation. The pooled proportion of rAAA was highest in December (incidence rate, 8.9%; 95% CI, 7.1%-10.9%; I2 = 54.5%) but lowest in July (incidence rate, 5.7%; 95% CI, 4.2%-7.3%; I2 = 54.5%). The IRR was significantly the highest in January (IRR, 1.14; 95% CI, 1.01-1.29; P = .031) but lowest in July (IRR, 0.75; 95% CI, 0.65-0.87; P < .0001). There is also some evidence for a possible association with atmospheric pressure. Associations with temperature and daylight hours, however, are at best speculative. CONCLUSIONS: Autumn and winter are significantly associated with a higher incidence of rAAAs, and autumn is associated with the highest rupture incidence of all the seasons. However, the inability to appropriately control for other confounding factors known to increase the risk of AAA rupture precludes any additional recommendations to alter current provision of vascular services on the basis of these data.

Receptor binding by an H7N9 influenza virus from humans.

Of the 132 people known to have been infected with H7N9 influenza viruses in China, 37 died, and many were severely ill. Infection seems to have involved contact with infected poultry. We have examined the receptor-binding properties of this H7N9 virus and compared them with those of an avian H7N3 virus. We find that the human H7 virus has significantly higher affinity for α-2,6-linked sialic acid analogues ('human receptor') than avian H7 while retaining the strong binding to α-2,3-linked sialic acid analogues ('avian receptor') characteristic of avian viruses. The human H7 virus does not, therefore, have the preference for human versus avian receptors characteristic of pandemic viruses. X-ray crystallography of the receptor-binding protein, haemagglutinin (HA), in complex with receptor analogues indicates that both human and avian receptors adopt different conformations when bound to human H7 HA than they do when bound to avian H7 HA. Human receptor bound to human H7 HA exits the binding site in a different direction to that seen in complexes formed by HAs from pandemic viruses and from an aerosol-transmissible H5 mutant. The human-receptor-binding properties of human H7 probably arise from the introduction of two bulky hydrophobic residues by the substitutions Gln226Leu and Gly186Val. The former is shared with the 1957 H2 and 1968 H3 pandemic viruses and with the aerosol-transmissible H5 mutant. We conclude that the human H7 virus has acquired some of the receptor-binding characteristics that are typical of pandemic viruses, but its retained preference for avian receptor may restrict its further evolution towards a virus that could transmit efficiently between humans, perhaps by binding to avian-receptor-rich mucins in the human respiratory tract rather than to cellular receptors.

Receptor binding by a ferret-transmissible H5 avian influenza virus.

Cell-surface-receptor binding by influenza viruses is a key determinant of their transmissibility, both from avian and animal species to humans as well as from human to human. Highly pathogenic avian H5N1 viruses that are a threat to public health have been observed to acquire affinity for human receptors, and transmissible-mutant-selection experiments have identified a virus that is transmissible in ferrets, the generally accepted experimental model for influenza in humans. Here, our quantitative biophysical measurements of the receptor-binding properties of haemagglutinin (HA) from the transmissible mutant indicate a small increase in affinity for human receptor and a marked decrease in affinity for avian receptor. From analysis of virus and HA binding data we have derived an algorithm that predicts virus avidity from the affinity of individual HA-receptor interactions. It reveals that the transmissible-mutant virus has a 200-fold preference for binding human over avian receptors. The crystal structure of the transmissible-mutant HA in complex with receptor analogues shows that it has acquired the ability to bind human receptor in the same folded-back conformation as seen for HA from the 1918, 1957 (ref. 4), 1968 (ref. 5) and 2009 (ref. 6) pandemic viruses. This binding mode is substantially different from that by which non-transmissible wild-type H5 virus HA binds human receptor. The structure of the complex also explains how the change in preference from avian to human receptors arises from the Gln226Leu substitution, which facilitates binding to human receptor but restricts binding to avian receptor. Both features probably contribute to the acquisition of transmissibility by this mutant virus.

EventFinder: a program for screening remotely captured images.

Camera traps are becoming ubiquitous tools for ecologists. While easily deployed, they require human time to organize, review, and classify images including sequences of images of the same individual, and non-target images triggered by environmental conditions. For such cases, we developed an automated computer program, named EventFinder, to reduce operator time by pre-processing and classifying images using background subtraction techniques and color histogram comparisons. We tested the accuracy of the program against images previously classified by a human operator. The automated classification, on average, reduced the data requiring human input by 90.8% with an accuracy of 96.1%, and produced a false positive rate of only 3.4%. Thus, EventFinder provides an efficient method for reducing the time for human operators to review and classify images making camera trap projects, which compile a large number of images, less costly to process. Our testing process used medium to large animals, but will also work with smaller animals, provided their images occupy a sufficient area of the frame. While our discussion focuses on camera trap image reduction, we also discuss how EventFinder might be used in conjunction with other software developments for managing camera trap data.

Transcriptome analysis of the Brassica napus-Leptosphaeria maculans pathosystem identifies receptor, signaling and structural genes underlying plant resistance.

The hemibiotrophic fungal pathogen Leptosphaeria maculans is the causal agent of blackleg disease in Brassica napus (canola, oilseed rape) and causes significant loss of yield worldwide. While genetic resistance has been used to mitigate the disease by means of traditional breeding strategies, there is little knowledge about the genes that contribute to blackleg resistance. RNA sequencing and a streamlined bioinformatics pipeline identified unique genes and plant defense pathways specific to plant resistance in the B. napus-L. maculans LepR1-AvrLepR1 interaction over time. We complemented our temporal analyses by monitoring gene activity directly at the infection site using laser microdissection coupled to quantitative PCR. Finally, we characterized genes involved in plant resistance to blackleg in the Arabidopsis-L. maculans model pathosystem. Data reveal an accelerated activation of the plant transcriptome in resistant host cotyledons associated with transcripts coding for extracellular receptors and phytohormone signaling molecules. Functional characterization provides direct support for transcriptome data and positively identifies resistance regulators in the Brassicaceae. Spatial gradients of gene activity were identified in response to L. maculans proximal to the site of infection. This dataset provides unprecedented spatial and temporal resolution of the genes required for blackleg resistance and serves as a valuable resource for those interested in host-pathogen interactions.

Structures of complexes formed by H5 influenza hemagglutinin with a potent broadly neutralizing human monoclonal antibody.

H5N1 avian influenza viruses remain a threat to public health mainly because they can cause severe infections in humans. These viruses are widespread in birds, and they vary in antigenicity forming three major clades and numerous antigenic variants. The most important features of the human monoclonal antibody FLD194 studied here are its broad specificity for all major clades of H5 influenza HAs, its high affinity, and its ability to block virus infection, in vitro and in vivo. As a consequence, this antibody may be suitable for anti-H5 therapy and as a component of stockpiles, together with other antiviral agents, for health authorities to use if an appropriate vaccine was not available. Our mutation and structural analyses indicate that the antibody recognizes a relatively conserved site near the membrane distal tip of HA, near to, but distinct from, the receptor-binding site. Our analyses also suggest that the mechanism of infectivity neutralization involves prevention of receptor recognition as a result of steric hindrance by the Fc part of the antibody. Structural analyses by EM indicate that three Fab fragments are bound to each HA trimer. The structure revealed by X-ray crystallography is of an HA monomer bound by one Fab. The monomer has some similarities to HA in the fusion pH conformation, and the monomer's formation, which results from the presence of isopropanol in the crystallization solvent, contributes to considerations of the process of change in conformation required for membrane fusion.