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We report genome-wide ancient DNA from 49 individuals forming four parallel time transects in Belize, Brazil, the Central Andes, and the Southern Cone, each dating to at least â¼9,000 years ago. The common ancestral population radiated rapidly from just one of the two early branches that contributed to Native Americans today. We document two previously unappreciated streams of gene flow between North and South America. One affected the Central Andes by â¼4,200 years ago, while the other explains an affinity between the oldest North American genome associated with the Clovis culture and the oldest Central and South Americans from Chile, Brazil, and Belize. However, this was not the primary source for later South Americans, as the other ancient individuals derive from lineages without specific affinity to the Clovis-associated genome, suggesting a population replacement that began at least 9,000 years ago and was followed by substantial population continuity in multiple regions.
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Genética de Población/historia , Genoma Humano , América Central , ADN Antiguo/análisis , ADN Mitocondrial/genética , Flujo Génico , Historia Antigua , Humanos , Modelos Teóricos , América del SurRESUMEN
Malaria-causing protozoa of the genus Plasmodium have exerted one of the strongest selective pressures on the human genome, and resistance alleles provide biomolecular footprints that outline the historical reach of these species1. Nevertheless, debate persists over when and how malaria parasites emerged as human pathogens and spread around the globe1,2. To address these questions, we generated high-coverage ancient mitochondrial and nuclear genome-wide data from P. falciparum, P. vivax and P. malariae from 16 countries spanning around 5,500 years of human history. We identified P. vivax and P. falciparum across geographically disparate regions of Eurasia from as early as the fourth and first millennia BCE, respectively; for P. vivax, this evidence pre-dates textual references by several millennia3. Genomic analysis supports distinct disease histories for P. falciparum and P. vivax in the Americas: similarities between now-eliminated European and peri-contact South American strains indicate that European colonizers were the source of American P. vivax, whereas the trans-Atlantic slave trade probably introduced P. falciparum into the Americas. Our data underscore the role of cross-cultural contacts in the dissemination of malaria, laying the biomolecular foundation for future palaeo-epidemiological research into the impact of Plasmodium parasites on human history. Finally, our unexpected discovery of P. falciparum in the high-altitude Himalayas provides a rare case study in which individual mobility can be inferred from infection status, adding to our knowledge of cross-cultural connectivity in the region nearly three millennia ago.
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ADN Antiguo , Genoma Mitocondrial , Genoma de Protozoos , Malaria , Plasmodium , Femenino , Humanos , Masculino , Altitud , Américas/epidemiología , Asia/epidemiología , Evolución Biológica , Resistencia a la Enfermedad/genética , ADN Antiguo/análisis , Europa (Continente)/epidemiología , Genoma Mitocondrial/genética , Genoma de Protozoos/genética , Historia Antigua , Malaria/parasitología , Malaria/historia , Malaria/transmisión , Malaria/epidemiología , Malaria Falciparum/epidemiología , Malaria Falciparum/historia , Malaria Falciparum/parasitología , Malaria Falciparum/transmisión , Malaria Vivax/epidemiología , Malaria Vivax/historia , Malaria Vivax/parasitología , Malaria Vivax/transmisión , Plasmodium/genética , Plasmodium/clasificación , Plasmodium falciparum/genética , Plasmodium falciparum/aislamiento & purificación , Plasmodium malariae/genética , Plasmodium malariae/aislamiento & purificación , Plasmodium vivax/genética , Plasmodium vivax/aislamiento & purificaciónRESUMEN
BACKGROUND: Distinct endothelial cell cycle states (early G1 versus late G1) provide different "windows of opportunity" to enable the differential expression of genes that regulate venous versus arterial specification, respectively. Endothelial cell cycle control and arteriovenous identities are disrupted in vascular malformations including arteriovenous shunts, the hallmark of hereditary hemorrhagic telangiectasia (HHT). To date, the mechanistic link between endothelial cell cycle regulation and the development of arteriovenous malformations (AVMs) in HHT is not known. METHODS: We used BMP (bone morphogenetic protein) 9/10 blocking antibodies and endothelial-specific deletion of activin A receptor like type 1 (Alk1) to induce HHT in Fucci (fluorescent ubiquitination-based cell cycle indicator) 2 mice to assess endothelial cell cycle states in AVMs. We also assessed the therapeutic potential of inducing endothelial cell cycle G1 state in HHT to prevent AVMs by repurposing the Food and Drug Administration-approved CDK (cyclin-dependent kinase) 4/6 inhibitor (CDK4/6i) palbociclib. RESULTS: We found that endothelial cell cycle state and associated gene expressions are dysregulated during the pathogenesis of vascular malformations in HHT. We also showed that palbociclib treatment prevented AVM development induced by BMP9/10 inhibition and Alk1 genetic deletion. Mechanistically, endothelial cell late G1 state induced by palbociclib modulates the expression of genes regulating arteriovenous identity, endothelial cell migration, metabolism, and VEGF-A (vascular endothelial growth factor A) and BMP9 signaling that collectively contribute to the prevention of vascular malformations. CONCLUSIONS: This study provides new insights into molecular mechanisms leading to HHT by defining how endothelial cell cycle is dysregulated in AVMs because of BMP9/10 and Alk1 signaling deficiencies, and how restoration of endothelial cell cycle control may be used to treat AVMs in patients with HHT.
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Malformaciones Arteriovenosas , Telangiectasia Hemorrágica Hereditaria , Humanos , Ratones , Animales , Telangiectasia Hemorrágica Hereditaria/genética , Telangiectasia Hemorrágica Hereditaria/patología , Factor A de Crecimiento Endotelial Vascular/metabolismo , Malformaciones Arteriovenosas/metabolismo , Células Endoteliales/metabolismo , Factor 2 de Diferenciación de Crecimiento/metabolismo , Puntos de Control del Ciclo CelularRESUMEN
Pestis secunda (1356-1366 CE) is the first of a series of plague outbreaks in Europe that followed the Black Death (1346-1353 CE). Collectively this period is called the Second Pandemic. From a genomic perspective, the majority of post-Black Death strains of Yersinia pestis thus far identified in Europe display diversity accumulated over a period of centuries that form a terminal sub-branch of the Y. pestis phylogeny. It has been debated if these strains arose from local evolution of Y. pestis or if the disease was repeatedly reintroduced from an external source. Plague lineages descended from the pestis secunda, however, are thought to have persisted in non-human reservoirs outside Europe, where they eventually gave rise to the Third Pandemic (19th and 20th centuries). Resolution of competing hypotheses on the origins of the many post-Black Death outbreaks has been hindered in part by the low representation of Y. pestis genomes in archaeological specimens, especially for the pestis secunda. Here we report on five individuals from Germany that were infected with lineages of plague associated with the pestis secunda. For the two genomes of high coverage, one groups within the known diversity of genotypes associated with the pestis secunda, while the second carries an ancestral genotype that places it earlier. Through consideration of historical sources that explore first documentation of the pandemic in today's Central Germany, we argue that these data provide robust evidence to support a post-Black Death evolution of the pathogen within Europe rather than a re-introduction from outside. Additionally, we demonstrate retrievability of Y. pestis DNA in post-cranial remains and highlight the importance of hypothesis-free pathogen screening approaches in evaluations of archaeological samples.
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Peste , Yersinia pestis , Humanos , Yersinia pestis/genética , Peste/epidemiología , ADN Bacteriano/genética , Genoma Bacteriano , Europa (Continente)/epidemiología , FilogeniaRESUMEN
BACKGROUND: Pulmonary hypertension (PH) accompanying COPD (PH-COPD) is associated with worse outcomes than COPD alone. There are currently no approved therapies to treat PH-COPD. The PERFECT study (ClinicalTrials.gov: NCT03496623) evaluated the safety and efficacy of inhaled treprostinil (iTRE) in this patient population. METHODS: Patients with PH-COPD (mean pulmonary arterial pressure ≥30â mmHg and pulmonary vascular resistance ≥4â WU) were enrolled in a multicentre, randomised (1:1), double-blind, placebo-controlled, 12-week, crossover study. A contingent parallel design was also prespecified and implemented, based on a blinded interim analysis of missing data. Patients received treatment with iTRE up to 12 breaths (72â µg) 4 times daily or placebo. The primary efficacy end-point was change in peak 6-min walk distance (6MWD) at week 12. RESULTS: In total, 76 patients were randomised, 64 in the original crossover design and 12 in the contingent parallel design; 66 patients received iTRE and 58 received placebo. The study was terminated early at the recommendation of the data and safety monitoring committee based on the totality of evidence that iTRE increased the risk of serious adverse events and suggestive evidence of an increased risk of mortality. The change in 6MWD was numerically worse with iTRE exposure than with placebo exposure. CONCLUSIONS: The risk-benefit observations associated with iTRE in patients with PH-COPD did not support continuation of the PERFECT study. The results of this study do not support iTRE as a viable treatment option in patients with PH-COPD.
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Antihipertensivos , Estudios Cruzados , Epoprostenol , Hipertensión Pulmonar , Enfermedad Pulmonar Obstructiva Crónica , Prueba de Paso , Humanos , Enfermedad Pulmonar Obstructiva Crónica/tratamiento farmacológico , Enfermedad Pulmonar Obstructiva Crónica/complicaciones , Epoprostenol/análogos & derivados , Epoprostenol/administración & dosificación , Epoprostenol/uso terapéutico , Femenino , Masculino , Hipertensión Pulmonar/tratamiento farmacológico , Administración por Inhalación , Anciano , Persona de Mediana Edad , Método Doble Ciego , Antihipertensivos/administración & dosificación , Antihipertensivos/uso terapéutico , Resultado del TratamientoRESUMEN
The last century has witnessed progress in the study of ancient infectious disease from purely medical descriptions of past ailments to dynamic interpretations of past population health that draw upon multiple perspectives. The recent adoption of high-throughput DNA sequencing has led to an expanded understanding of pathogen presence, evolution, and ecology across the globe. This genomic revolution has led to the identification of disease-causing microbes in both expected and unexpected contexts, while also providing for the genomic characterization of ancient pathogens previously believed to be unattainable by available methods. In this review we explore the development of DNA-based ancient pathogen research, the specialized methods and tools that have emerged to authenticate and explore infectious disease of the past, and the unique challenges that persist in molecular paleopathology. We offer guidelines to mitigate the impact of these challenges, which will allow for more reliable interpretations of data in this rapidly evolving field of investigation.
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Enfermedades Transmisibles/historia , ADN Antiguo/análisis , Fósiles/microbiología , Paleopatología/métodos , Evolución Biológica , ADN Bacteriano , Fósiles/parasitología , Genoma Bacteriano , Genómica/métodos , Helicobacter pylori/genética , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Historia Antigua , Humanos , Mycobacterium leprae/genética , Mycobacterium tuberculosis/genética , Paleontología/métodos , Filogenia , Yersinia pestis/genéticaRESUMEN
BACKGROUND: Male sex workers (MSWs), specifically cisgender men who exchange sex for money, goods, drugs, or other items of value with other cisgender men, are at high risk for HIV infection. Compared to men not engaged in sex work, MSWs are more likely to engage in frequent condomless sex with paying and non-paying sexual partners. While MSWs are often included as a subgroup of gay and bisexual men, data show that a large proportion identify as heterosexual; additionally, most MSWs do not identify as "sex workers." This places MSWs in a unique position where they may not engage with traditional HIV prevention programs, and when they do, they may not feel comfortable, leading to poor retention. Thus, HIV prevention interventions that address MSWs' unique life circumstances and provide support in exploring their sexual health options are needed. METHODS: In this protocol paper, we describe the design and procedures for a National Institute of Health-funded, randomized controlled trial testing the efficacy of "PrEPare for Work,"- a theory-based, manualized PrEP uptake and adherence intervention for MSW - using a 2-stage randomization design. Stage 1: MSWs are equally randomized to receive either the "PrEPare for Work Stage 1 intervention" (strength-based case management and facilitated PrEP linkage) or Standard of Care (SOC) to evaluate successful PrEP uptake (prescription filled) within two months post-randomization. Stage 2: Those who initiate PrEP are then equally re-randomized to receive either the "PrEPare for Work Stage 2 intervention" (1-on-1 skills training, problem-solving, and motivational interviewing adherence counseling and personalized, daily text message reminders) or SOC to assess adherence (Tenofovir concentrations in hair) over 12 months of follow up. Planned analyses will examine intervention efficacy, specific conceptual mediators, and hypothesized moderators. DISCUSSION: Based on our extensive preliminary research, multi-component, theory-informed interventions targeting this subpopulation of MSWs' unique life circumstances are urgently needed. In this study, we are evaluating whether "PrEPare for Work" can improve PrEP uptake and adherence among MSWs. If this intervention is efficacious, it would be readily disseminated to diverse community organizations that serve MSWs and possibly other community or clinic-based settings. TRIAL REGISTRATION: ClinicalTrials.gov number NCT05736614, registered February 8, 2023.
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Fármacos Anti-VIH , Infecciones por VIH , Profilaxis Pre-Exposición , Trabajadores Sexuales , Masculino , Humanos , Infecciones por VIH/prevención & control , Infecciones por VIH/psicología , Homosexualidad Masculina/psicología , Conducta Sexual , Consejo , Profilaxis Pre-Exposición/métodos , Fármacos Anti-VIH/uso terapéutico , Ensayos Clínicos Controlados Aleatorios como AsuntoRESUMEN
Diabetic foot ulcers (DFUs) often become infected and are treated with antimicrobials, with samples collected to inform care. Swab samples are easier than tissue sampling but report fewer organisms. Compared with culture and sensitivity (C&S) methods, molecular microbiology identifies more organisms. Clinician perspectives on sampling and processing are unknown. We explored clinician perspectives on DFU sampling-tissue samples/wound swabs-and on processing techniques, culture and sensitivity or molecular techniques. The latter provides information on organisms which have not survived transport to the laboratory for culture. We solicited feedback on molecular microbiology reports. Qualitative study using semi-structured interview, with analysis using a Framework approach. CODIFI2 clinicians from UK DFU clinics. Seven consultants agreed to take part. They reported, overall, a preference for tissue samples over swabbing. Clinicians were not confident replacing C&S with molecular microbiology as the approach to reporting was unfamiliar. The study was small and did not recruit any podiatrists or nurses, who may have discipline-specific attitudes or perspectives on DFU care. Both sampling approaches appear to be used by clinicians. Molecular microbiology reports would not be, at present, suitable for replacement of traditional culture and sensitivity.
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Pie Diabético , Investigación Cualitativa , Manejo de Especímenes , Pie Diabético/microbiología , Pie Diabético/terapia , Humanos , Manejo de Especímenes/métodos , Masculino , Femenino , Reino Unido , Persona de Mediana Edad , Adulto , Anciano , Infección de Heridas/microbiología , Infección de Heridas/terapiaRESUMEN
Fast frame rates are desirable in scanning transmission electron microscopy for a number of reasons: controlling electron beam dose, capturing in situ events, or reducing the appearance of scan distortions. While several strategies exist for increasing frame rates, many impact image quality or require investment in advanced scan hardware. Here, we present an interlaced imaging approach to achieve minimal loss of image quality with faster frame rates that can be implemented on many existing scan controllers. We further demonstrate that our interlacing approach provides the best possible strain precision for a given electron dose compared with other contemporary approaches.
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Neglected diseases caused by arenaviruses such as Lassa virus (LASV) and filoviruses like Ebola virus (EBOV) primarily afflict resource-limited countries, where antiviral drug development is often minimal. Previous studies have shown that many approved drugs developed for other clinical indications inhibit EBOV and LASV and that combinations of these drugs provide synergistic suppression of EBOV, often by blocking discrete steps in virus entry. We hypothesize that repurposing of combinations of orally administered approved drugs provides effective suppression of arenaviruses. In this report, we demonstrate that arbidol, an approved influenza antiviral previously shown to inhibit EBOV, LASV, and many other viruses, inhibits murine leukemia virus (MLV) reporter viruses pseudotyped with the fusion glycoproteins (GPs) of other arenaviruses (Junin virus [JUNV], lymphocytic choriomeningitis virus [LCMV], and Pichinde virus [PICV]). Arbidol and other approved drugs, including aripiprazole, amodiaquine, sertraline, and niclosamide, also inhibit infection of cells by infectious PICV, and arbidol, sertraline, and niclosamide inhibit infectious LASV. Combining arbidol with aripiprazole or sertraline results in the synergistic suppression of LASV and JUNV GP-bearing pseudoviruses. This proof-of-concept study shows that arenavirus infection in vitro can be synergistically inhibited by combinations of approved drugs. This approach may lead to a proactive strategy with which to prepare for and control known and new arenavirus outbreaks.
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Antivirales/uso terapéutico , Infecciones por Arenaviridae/tratamiento farmacológico , Arenavirus/efectos de los fármacos , Administración Oral , Animales , Infecciones por Arenaviridae/virología , Línea Celular , Chlorocebus aethiops , Sinergismo Farmacológico , Quimioterapia Combinada/métodos , Células HEK293 , Humanos , Ratones , Prueba de Estudio Conceptual , Células VeroRESUMEN
OBJECTIVE: To explore whether placebo surgery controlled trials achieve what they set out to do by investigating discrepancy between projected and actual design aspects of trials identified through systematic review methods. SUMMARY BACKGROUND: Interest in placebo surgery controlled trials is growing in response to concerns regarding unnecessary surgery and the societal cost of low-value healthcare. As questions about the justifiability of using placebo controls in surgery have been addressed, attention is now being paid to more practical concerns. METHODS: Six databases were searched from inception - May 2020 (MEDLINE, Embase, Emcare, APA PsycInfo, CINAHL, Cochrane Library). Placebo surgery controlled trials with a published protocol were included. Three authors extracted "projected" design aspects from protocols and "actual" design aspects from main findings papers. Absolute and relative difference between projected and actual design aspects were presented for each trial. Trials were grouped according to whether they met their target sample size ("completed") and were concluded in a timely fashion. Pairs of authors assessed risk of bias. RESULTS: Of 24 trials with data available to analyse; 3 were completed and concluded within target timeframe; 10 were completed and concluded outside the target timeline; 4 were completed without clear target timeframes; 2 were incomplete and concluded within the target framework; 5 were incomplete and concluded outside the target timeline. Trials which reached the recruitment target underestimated trial duration by 88% and number of recruitment sites by 87%. CONCLUSIONS: Trialists need to factor additional time and sites into future placebo surgery controlled trials. A robust reporting framework of projected and actual trial design is imperative for trialists to learn from their predecessors. REVIEW REGISTRATION: PROSPERO (CRD42019133296).
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Ensayos Clínicos Controlados como Asunto/métodos , Placebos , Procedimientos Quirúrgicos Operativos , HumanosRESUMEN
The foundations of medical education have drawn from the Flexner Report to prepare students for practice for over a century. These recommendations relied, however, upon a limited set of competencies and a relatively narrow view of the physician's role. There have been increasing calls and recommendations to expand those competencies and the professional identity of the physician to better meet the current and future needs of patients, health systems, and society. We propose a framework for the twenty-first century physician that includes an expectation of new competency in health systems science (HSS), creating 'system citizens' who are effective stewards of the health care system. Experiential educational strategies, in addition to knowledge-centered learning, are critically important for students to develop their professional identity as system citizens working alongside interprofessional colleagues. Challenges to HSS adoption range from competing priorities for learners, to the need for faculty development, to the necessity for buy-in by medical schools and their associated health care systems. Ultimately, success will depend on our ability to articulate, encourage, support, and evaluate system citizenship and its impact on health care and health care systems.
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Educación Médica , Profesionalismo , Curriculum , Atención a la Salud , Humanos , Rol del MédicoRESUMEN
BACKGROUND: An innovative medical student elective combined student-directed, faculty-supported online learning with COVID-19 response field placements. This study evaluated students' experience in the course, the curriculum content and format, and its short-term impact on students' knowledge and attitudes around COVID-19. METHODS: Students responded to discussion board prompts throughout the course and submitted pre-/post-course reflections. Pre-/post-course questionnaires assessed pandemic knowledge and attitudes using 4-point Likert scales. Authors collected aggregate data on enrollment, discussion posts, field placements, and scholarly work resulting from course activities. After the elective, authors conducted a focus group with a convenience sample of 6 participants. Institutional elective evaluation data was included in analysis. Authors analyzed questionnaire data with summary statistics and paired t-tests comparing knowledge and attitudes before and after the elective. Reflection pieces, discussion posts, and focus group data were analyzed using content analysis with a phenomenological approach. RESULTS: Twenty-seven students enrolled. Each student posted an average of 2.4 original discussion posts and 3.1 responses. Mean knowledge score increased from 43.8 to 60.8% (p < 0.001) between pre- and post-course questionnaires. Knowledge self-assessment also increased (2.4 vs. 3.5 on Likert scale, p < 0.0001), and students reported increased engagement in the pandemic response (2.7 vs. 3.6, p < 0.0001). Students reported increased fluency in discussing the pandemic and increased appreciation for the field of public health. There was no difference in students' level of anxiety about the pandemic after course participation (3.0 vs. 3.1, p = 0.53). Twelve students (44.4%) completed the institutional evaluation. All rated the course "very good" or "excellent." Students favorably reviewed the field placements, suggested readings, self-directed research, and learning from peers. They suggested more clearly defined expectations and improved balance between volunteer and educational hours. CONCLUSIONS: The elective was well-received by students, achieved stated objectives, and garnered public attention. Course leadership should monitor students' time commitment closely in service-learning settings to ensure appropriate balance of service and education. Student engagement in a disaster response is insufficient to address anxiety related to the disaster; future course iterations should include a focus on self-care during times of crisis. This educational innovation could serve as a model for medical schools globally.
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COVID-19/epidemiología , Educación Médica/organización & administración , Curriculum , Educación a Distancia/métodos , Educación a Distancia/organización & administración , Educación Médica/métodos , Educación en Salud Pública Profesional/métodos , Educación en Salud Pública Profesional/organización & administración , Evaluación Educacional , Femenino , Humanos , Masculino , Estudiantes de MedicinaRESUMEN
OBJECTIVE: To describe a modified celiotomy to improve access to cranial abdominal structures in horses. ANIMALS: Four horses. STUDY DESIGN: Short case series. METHODS: Three horses with gastric impactions were treated with gastrotomies. One horse was treated for a diaphragmatic hernia with herniorrhaphy and mesh augmentation. In all horses, the ventral midline celiotomy was modified cranially with a J-incision through the body wall, along the paracostal arch. RESULTS: The only surgical complications were midline incisional infections in all horses. Three of the four horses had good long-term outcomes; the remaining horse underwent euthanasia for reasons likely unrelated to incisional complications. CONCLUSION: The J-incision improved access to the stomach and diaphragm in these horses. The paracostal component healed in all cases without evidence of infection or dehiscence. CLINICAL SIGNIFICANCE: This modified celiotomy may be considered to improve access during gastrotomy and repair of dorsally located diaphragmatic hernias.
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Abdomen/cirugía , Laparotomía/veterinaria , Infección de la Herida Quirúrgica/veterinaria , Herida Quirúrgica/veterinaria , Animales , Hernia Diafragmática/cirugía , Hernia Diafragmática/veterinaria , Caballos , Laparotomía/métodos , Masculino , Estómago/cirugía , Herida Quirúrgica/complicaciones , Infección de la Herida Quirúrgica/etiologíaRESUMEN
Influenza virus is an RNA virus encapsulated in a lipid bilayer derived from the host cell plasma membrane. Previous studies showed that influenza virus infection depends on cellular lipids, including the sphingolipids sphingomyelin and sphingosine. Here we examined the role of a third sphingolipid, glucosylceramide, in influenza virus infection following clustered regularly interspaced short palindromic repeats with Cas9 (CRISPR-Cas9)-mediated knockout (KO) of its metabolizing enzyme glucosylceramidase (GBA). After confirming GBA knockout of HEK 293 and A549 cells by both Western blotting and lipid mass spectrometry, we observed diminished infection in both KO cell lines by a PR8 (H1N1) green fluorescent protein (GFP) reporter virus. We further showed that the reduction in infection correlated with impaired influenza virus trafficking to late endosomes and hence with fusion and entry. To examine whether GBA is required for other enveloped viruses, we compared the results seen with entry mediated by the glycoproteins of Ebola virus, influenza virus, vesicular stomatitis virus (VSV), and measles virus in GBA knockout cells. Entry inhibition was relatively robust for Ebola virus and influenza virus, modest for VSV, and mild for measles virus, suggesting a greater role for viruses that enter cells by fusing with late endosomes. As the virus studies suggested a general role for GBA along the endocytic pathway, we tested that hypothesis and found that trafficking of epidermal growth factor (EGF) to late endosomes and degradation of its receptor were impaired in GBA knockout cells. Collectively, our findings suggest that GBA is critically important for endocytic trafficking of viruses as well as of cellular cargos, including growth factor receptors. Modulation of glucosylceramide levels may therefore represent a novel accompaniment to strategies to antagonize "late-penetrating" viruses, including influenza virus.IMPORTANCE Influenza virus is the pathogen responsible for the second largest pandemic in human history. A better understanding of how influenza virus enters host cells may lead to the development of more-efficacious therapies against emerging strains of the virus. Here we show that the glycosphingolipid metabolizing enzyme glucosylceramidase is required for optimal influenza virus trafficking to late endosomes and for consequent fusion, entry, and infection. We also provide evidence that promotion of influenza virus entry by glucosylceramidase extends to other endosome-entering viruses and is due to a general requirement for this enzyme, and hence for optimal levels of glucosylceramide, for efficient trafficking of endogenous cargos, such as the epidermal growth factor (EGF) receptor, along the endocytic pathway. This work therefore has implications for the basic process of endocytosis as well as for pathogenic processes, including virus entry and Gaucher disease.
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Endocitosis/fisiología , Glucosilceramidasa/metabolismo , Orthomyxoviridae/metabolismo , Células A549 , Ebolavirus/metabolismo , Endosomas/metabolismo , Factor de Crecimiento Epidérmico/metabolismo , Receptores ErbB/metabolismo , Glucosilceramidasa/fisiología , Células HEK293 , Humanos , Subtipo H1N1 del Virus de la Influenza A/metabolismo , Virus de la Influenza A/fisiología , Virus del Sarampión/metabolismo , Internalización del VirusRESUMEN
Ebolavirus (EBOV), an enveloped filamentous RNA virus causing severe hemorrhagic fever, enters cells by macropinocytosis and membrane fusion in a late endosomal compartment. Fusion is mediated by the EBOV envelope glycoprotein GP, which consists of subunits GP1 and GP2. GP1 binds to cellular receptors, including Niemann-Pick C1 (NPC1) protein, and GP2 is responsible for low pH-induced membrane fusion. Proteolytic cleavage and NPC1 binding at endosomal pH lead to conformational rearrangements of GP2 that include exposing the hydrophobic fusion loop (FL) for insertion into the cellular target membrane and forming a six-helix bundle structure. Although major portions of the GP2 structure have been solved in pre- and postfusion states and although current models place the transmembrane (TM) and FL domains of GP2 in close proximity at critical steps of membrane fusion, their structures in membrane environments, and especially interactions between them, have not yet been characterized. Here, we present the structure of the membrane proximal external region (MPER) connected to the TM domain: i.e., the missing parts of the EBOV GP2 structure. The structure, solved by solution NMR and EPR spectroscopy in membrane-mimetic environments, consists of a helix-turn-helix architecture that is independent of pH. Moreover, the MPER region is shown to interact in the membrane interface with the previously determined structure of the EBOV FL through several critical aromatic residues. Mutation of aromatic and neighboring residues in both binding partners decreases fusion and viral entry, highlighting the functional importance of the MPER/TM-FL interaction in EBOV entry and fusion.
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Ebolavirus/química , Proteínas del Envoltorio Viral/química , Proteínas Virales de Fusión/química , Membrana Celular/química , Membrana Celular/metabolismo , Membrana Celular/virología , Ebolavirus/fisiología , Dominios Proteicos , Estructura Secundaria de Proteína , Relación Estructura-Actividad , Proteínas del Envoltorio Viral/metabolismo , Proteínas Virales de Fusión/metabolismo , Internalización del VirusRESUMEN
Issue: Despite clear relevance, need, descriptive literature, and student interest, few schools offer required curriculum to develop leadership skills. This paper outlines a proposed shared vision for leadership development drawn from a coalition of diverse medical schools. We advocate that leadership development is about self (looking inward), teams (not hierarchy), and change (looking outward). We propose that leadership development is for all medical students, not for a subset, and we believe that leadership curricula and programs must be experiential and applied. Evidence: This paper also draws on the current literature and the experience of medical schools participating in the American Medical Association's (AMA) Accelerating Change in Medical Education Consortium, confronts the common arguments against leadership training in medical education, and provides three cross-cutting principles that we believe must each be incorporated in all medical student-centered leadership development programs as they emerge and evolve at medical schools. Implications: By confronting common arguments against leadership training and providing a framework for such training, we give medical educators important tools and insights into developing leadership training for all students at their institutions.
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Consenso , Liderazgo , Facultades de Medicina , Estudiantes de Medicina , Curriculum , Educación de Pregrado en MedicinaRESUMEN
Background: A need to develop therapeutics to treat Ebola virus disease patients in remote and resource-challenged settings remains in the wake of the 2013-2016 epidemic in West Africa. Toward this goal, we screened drugs under consideration as treatment options and other drugs of interest, most being small molecules approved by the Food and Drug Administration. Drugs demonstrating in vitro antiviral activity were advanced for evaluation in combinations because of advantages often provided by drug cocktails. Methods: Drugs were screened for blockade of Ebola virus infection in cultured cells. Twelve drugs were tested in all (78 pair-wise) combinations, and 3 were tested in a subset of combinations. Results: Multiple synergistic drug pairs emerged, with the majority comprising 2 entry inhibitors. For the pairs of entry inhibitors studied, synergy was demonstrated at the level of virus entry into host cells. Highly synergistic pairs included aripiprazole/piperacetazine, sertraline/toremifene, sertraline/bepridil, and amodiaquine/clomiphene. Conclusions: Our study shows the feasibility of identifying pairs of approved drugs that synergistically block Ebola virus infection in cell cultures. We discuss our findings in terms of the theoretic ability of these or alternate combinations to reach therapeutic levels. Future research will assess selected combinations in small-animal models of Ebola virus disease.
Asunto(s)
Antivirales/administración & dosificación , Ebolavirus/efectos de los fármacos , Animales , Antivirales/uso terapéutico , Chlorocebus aethiops , Aprobación de Drogas , Sinergismo Farmacológico , Quimioterapia Combinada , Células Vero , Virión/efectos de los fármacos , Internalización del Virus/efectos de los fármacosRESUMEN
Psychiatrist Édouard Toulouse (1865-1947) is known today for his 1896 psychometric study of the novelist Émile Zola, and his contributions to mental hygiene, sexology, eugenics, and labour efficiency in inter-war France. This paper examines research undertaken in Toulouse's Laboratory of Experimental Psychology at the Villejuif asylum near Paris. In 1905, Toulouse created a test that could differentiate between dementia and mental confusion, a test that could aid in the classification of patients at the overcrowded Villejuif facility. By 1920, however, the test's early promise was undercut by unforeseen, 'machinic' resistance that emerged in the experimental process. This case study demonstrates the non-linear nature of scientific practice and limits of even the most innovative asylum reforms in this period.
Asunto(s)
Demencia/historia , Psicología Experimental/historia , Investigación Biomédica/historia , Demencia/diagnóstico , Diagnóstico Diferencial , Francia , Historia del Siglo XIX , Historia del Siglo XX , Hospitales Psiquiátricos/historia , Humanos , Encuestas y CuestionariosRESUMEN
BACKGROUND: Currently, seven equine papillomaviruses (PV) are known and are associated with one of three different and distinct clinical presentations. HYPOTHESIS/OBJECTIVES: To report the clinical, histopathological and immunohistochemical findings in horses with generalized papillomatosis associated with a novel equine PV, Equus caballus papillomavirus 8 (EcPV8). ANIMALS: Three client-owned quarter horses. METHODS: Case report, retrospective. RESULTS: Dozens to thousands of papillomas involved the axilla, inguinal area and proximal limbs as well as the ventral and lateral neck, thorax and abdomen. Lesions were sometimes confluent in ventral areas. Fewer lesions were on the face, ears, distal limbs and genitalia. Plaque-type papillomas were small, 0.5 to 1.5 cm in diameter and hyperkeratotic. Histologically, plaque-type papillomas prominently involved follicular infundibula. Immunohistochemical findings demonstrated PV antigen in superficial keratinocyte nuclei. PCR using degenerate primers for the PV L1 gene and sequencing of amplicons revealed PV DNA sequences that were 98% identical for all three cases, but shared <70% identity to other PVs. Horses were otherwise healthy; serum immunoglobulin levels and peripheral blood lymphocyte phenotyping did not identify a known immunodeficiency syndrome. Lesions nearly completely resolved after 1.5 years in one horse and persisted for two years in another, despite intralesional human IFN-alpha treatment. The oldest horse was lost to follow-up. CONCLUSION AND CLINICAL IMPORTANCE: A novel equine papillomavirus (EcPV8) is associated with a distinct, plaque-type, generalized papillomatosis. Papillomas persisted for months to years, with or without treatment.