113 research outputs found

    Effects of Entomopathogenic Chromobacterium (Csp_P) Exposure on the Microbiota and Fitness of Anopheles gambiae

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    Evidence that the mosquito’s microbiota can alter Plasmodium susceptibility has led to interest in manipulating the mosquito microbiome to interfere with malaria transmission. Microbes that mosquitoes naturally harbor may modulate vectorial capacity by altering vector competence, daily survival, blood-feeding behavior or vector density. Anopheles exposed to Chromobacterium (Csp_P), a bacterium isolated from field-caught Aedes aegypti, are more resistant to Plasmodium infection and are killed efficiently. This study evaluated the impact of Csp_P on fitness, multigenerational killing efficiency, and midgut microbiota composition in exposed Anopheles gambiae. To assess the effects on fitness parameters in exposed females, mosquitoes were fed a low (10^2 CFU/mL) or a high (10^7 CFU/mL) dose of Csp_P or Pantoea spp. (P. sp.) in an artificial nectar meal, and were subsequently offered a blood meal and allowed to oviposit. In a separate experiment, the offspring of females fed Csp_P (10^7 CFU/mL) were reared to measure transgenerational fitness effects. First generation offspring were exposed to Csp_P as either larvae or adults to test Csp_P’s multigenerational killing capacity. To measure the effect of Csp_P ingestion on the cultivable midgut microbiota, females were fed a high dose of either Csp_P, Enterobacter sp. Zambia (Esp_Z), or P sp., and, at 24 and 96 hours, individual midguts were dissected and plated on LB agar. Exposure to either dose of Csp_P or P. sp. did not alter the proportion ovipositing females or the number of eggs oviposited. Only adults fed Csp_P at the higher dose experienced reduced longevity. Maternal exposure to Csp_P significantly decreased survival, time to pupation, and survival of larval offspring; however, the life span and sex ratio of adult offspring was unaffected. When challenged with Csp_P, the F1 offspring of Csp_P-exposed females were killed as quickly as the F1 larvae of PBS-controls. Ingestion of Csp_P does not affect the total number or prevalence of the endogenous, cultivable bacteria. Overall, Csp_P (10^7 CFU/mL) attenuates the lifespan of exposed females without significantly impacting fecundity, oviposition, or midgut microbiota composition. Furthermore, this bacterial strain perturbs the development and eclosion of first-generation offspring and maintains killing efficiency over at least two consecutive generations

    Distancing Measures and Challenges Discussed by COVID-19 Outbreak Teams of Dutch Nursing Homes:The COVID-19 MINUTES Study

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    The most severe COVID-19 infections and highest mortality rates are seen among long-term care residents. To reduce the risk of infection, physical distancing is important. This study investigates what physical distancing measures were discussed by COVID-19 outbreak teams of Dutch long-term care organizations and what challenges they encountered. The COVID-19 MINUTES study is a qualitative multi-center study (n = 41) that collected minutes of COVID-19 outbreak teams from March 2020 to October 2021. Textual units about distancing measures were selected and analyzed using manifest content analysis for the first wave: early March-early May 2020; the intermediate period of 2020: mid-May-mid-September 2020; and the second wave: late September 2020-mid-June 2021. During all periods, COVID-19 outbreak teams often discussed distancing visitors from residents. Moreover, during the first wave they often discussed isolation measures, during the intermediate period they often discussed distancing staff and volunteers from residents, and during both the intermediate period and the second wave they often discussed distancing among residents. During all periods, less often admission measures were discussed. Challenges persisted and included unrest among and conflicts between visitors and staff, visitors violating measures, resident non-adherence to measures, and staffing issues. The discussed distancing measures and corresponding challenges may guide local long-term care and (inter)national policymakers during the further course of the COVID-19 pandemic, outbreaks of other infectious diseases, and long-term care innovations

    COVID-19 management in nursing homes by outbreak teams (MINUTES)-study description and data characteristics:A qualitative study

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    OBJECTIVES: Nursing homes are hit relatively hard by the COVID-19 pandemic. Dutch long-term care (LTC) organisations installed outbreak teams (OTs) to coordinate COVID-19 infection prevention and control. LTC organisations and relevant national policy organisations expressed the need to share experiences from these OTs that can be applied directly in COVID-19 policy. The aim of the ‘COVID-19 management in nursing homes by outbreak teams’ (MINUTES) study is to describe the challenges, responses and the impact of the COVID-19 pandemic in Dutch nursing homes. In this first article, we describe the MINUTES Study and present data characteristics. DESIGN: This large-scale multicentre study has a qualitative design using manifest content analysis. The participating organisations shared their OT minutes and other meeting documents on a weekly basis. Data from week 16 (April) to week 53 (December) 2020 included the first two waves of COVID-19. SETTING: National study with 41 large Dutch LTC organisations. PARTICIPANTS: The LTC organisations represented 563 nursing home locations and almost 43 000 residents. RESULTS: At least 36 of the 41 organisations had one or more SARS-CoV-2 infections among their residents. Most OTs were composed of management, medical staff, support services staff, policy advisors and communication specialists. Topics that emerged from the documents were: crisis management, isolation of residents, personal protective equipment and hygiene, staff, residents’ well-being, visitor policies, testing and vaccination. CONCLUSIONS: OT meeting minutes are a valuable data source to monitor the impact of and responses to COVID-19 in nursing homes. Depending on the course of the COVID-19 pandemic, data collection and analysis will continue until November 2021. The results are used directly in national and organisational COVID-19 policy

    Orbitofrontal gray matter relates to early morning awakening: a neural correlate of insomnia complaints?

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    Sleep complaints increase profoundly with age; prevalence estimates of insomnia in elderly people reach up to 37%. The three major types of nocturnal complaints are difficulties initiating sleep (DIS), difficulties maintaining sleep (DMS) and early morning awakening (EMA), of which the latter appears most characteristic for aging. The neural correlates associated with these complaints have hardly been investigated, hampering the development of rational treatment and prevention. A recent study on structural brain correlates of insomnia showed that overall severity, but not duration, of insomnia complaints is associated with lower gray matter (GM) density in part of the left orbitofrontal cortex. Following up on this, we investigated, in an independent sample of people not diagnosed with insomnia, whether individual differences in GM density are associated with differences in DIS, DMS and EMA.65 healthy participants filled out questionnaires and underwent structural magnetic resonance imaging. Three compound Z-scores were computed for questionnaire items relating to DIS, DMS and EMA. Whole-brain voxel-based morphometry was used to investigate their association with GM density. Results show that participants with lower GM density in a region where the left inferior orbitofrontal cortex borders the insula report more EMA, but not DIS or DMS.This is the first study to investigate structural brain correlates of specific sleep characteristics that can translate into complaints in insomniacs. The selective association of EMA with orbitofrontal GM density makes our findings particularly relevant to elderly people, where EMA represents the most characteristic complaint. It is hypothesized that low GM density in aforementioned orbitofrontal area affects its role in sensing comfort. An intact ability to evaluate comfort may be crucial to maintain sleep, especially at the end of the night when sleep is vulnerable because homeostatic sleep propensity has dissipated

    Resectability and Ablatability Criteria for the Treatment of Liver Only Colorectal Metastases:Multidisciplinary Consensus Document from the COLLISION Trial Group

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    The guidelines for metastatic colorectal cancer crudely state that the best local treatment should be selected from a 'toolbox' of techniques according to patient- and treatment-related factors. We created an interdisciplinary, consensus-based algorithm with specific resectability and ablatability criteria for the treatment of colorectal liver metastases (CRLM). To pursue consensus, members of the multidisciplinary COLLISION and COLDFIRE trial expert panel employed the RAND appropriateness method (RAM). Statements regarding patient, disease, tumor and treatment characteristics were categorized as appropriate, equipoise or inappropriate. Patients with ECOG≤2, ASA≤3 and Charlson comorbidity index ≤8 should be considered fit for curative-intent local therapy. When easily resectable and/or ablatable (stage IVa), (neo)adjuvant systemic therapy is not indicated. When requiring major hepatectomy (stage IVb), neo-adjuvant systemic therapy is appropriate for early metachronous disease and to reduce procedural risk. To downstage patients (stage IVc), downsizing induction systemic therapy and/or future remnant augmentation is advised. Disease can only be deemed permanently unsuitable for local therapy if downstaging failed (stage IVd). Liver resection remains the gold standard. Thermal ablation is reserved for unresectable CRLM, deep-seated resectable CRLM and can be considered when patients are in poor health. Irreversible electroporation and stereotactic body radiotherapy can be considered for unresectable perihilar and perivascular CRLM 0-5cm. This consensus document provides per-patient and per-tumor resectability and ablatability criteria for the treatment of CRLM. These criteria are intended to aid tumor board discussions, improve consistency when designing prospective trials and advance intersociety communications. Areas where consensus is lacking warrant future comparative studies.</p

    Molecular basis of Lys11-polyubiquitin specificity in the deubiquitinase Cezanne

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    The post-translational modification of proteins with polyubiquitin regulates virtually all aspects of cell biology. Eight distinct chain linkage types in polyubiquitin co-exist and are independently regulated in cells. This ‘ubiquitin code’ determines the fate of the modified protein1. Deubiquitinating enzymes of the Ovarian Tumour (OTU) family regulate cellular signalling by targeting distinct linkage types within polyubiquitin2, and understanding their mechanisms of linkage specificity gives fundamental insights into the ubiquitin system. We here reveal how the deubiquitinase Cezanne/OTUD7B specifically targets Lys11-linked polyubiquitin. Crystal structures of Cezanne alone and in complex with mono- and Lys11-linked diubiquitin, in combination with hydrogen-deuterium exchange mass spectrometry, enable reconstruction of the enzymatic cycle in exquisite detail. An intricate mechanism of ubiquitin-assisted conformational changes activate the enzyme, and while all chain types interact with the enzymatic S1 site, only Lys11-linked chains can bind productively across the active site and stimulate catalytic turnover. Our work highlights the fascinating plasticity of deubiquitinases, and indicates that new conformational states can occur when a true substrate, such as diubiquitin, is bound at the active site
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