97 research outputs found

    The Absence of C-5 DNA Methylation in Leishmania donovani Allows DNA Enrichment from Complex Samples.

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    Cytosine C5 methylation is an important epigenetic control mechanism in a wide array of eukaryotic organisms and generally carried out by proteins of the C-5 DNA methyltransferase family (DNMTs). In several protozoans, the status of this mechanism remains elusive, such as in Leishmania, the causative agent of the disease leishmaniasis in humans and a wide array of vertebrate animals. In this work, we showed that the Leishmania donovani genome contains a C-5 DNA methyltransferase (DNMT) from the DNMT6 subfamily, whose function is still unclear, and verified its expression at the RNA level. We created viable overexpressor and knock-out lines of this enzyme and characterized their genome-wide methylation patterns using whole-genome bisulfite sequencing, together with promastigote and amastigote control lines. Interestingly, despite the DNMT6 presence, we found that methylation levels were equal to or lower than 0.0003% at CpG sites, 0.0005% at CHG sites, and 0.0126% at CHH sites at the genomic scale. As none of the methylated sites were retained after manual verification, we conclude that there is no evidence for DNA methylation in this species. We demonstrated that this difference in DNA methylation between the parasite (no detectable DNA methylation) and the vertebrate host (DNA methylation) allowed enrichment of parasite vs. host DNA using methyl-CpG-binding domain columns, readily available in commercial kits. As such, we depleted methylated DNA from mixes of Leishmania promastigote and amastigote DNA with human DNA, resulting in average Leishmania:human enrichments from 62× up to 263×. These results open a promising avenue for unmethylated DNA enrichment as a pre-enrichment step before sequencing Leishmania clinical samples

    Barriers to apply cardiovascular prediction rules in primary care: a postal survey

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    BACKGROUND: Although cardiovascular prediction rules are recommended by guidelines to evaluate global cardiovascular risk for primary prevention, they are rarely used in primary care. Little is known about barriers for application. The objective of this study was to evaluate barriers impeding the application of cardiovascular prediction rules in primary prevention. METHODS: We performed a postal survey among general physicians in two Swiss Cantons by a purpose designed questionnaire. RESULTS: 356 of 772 dispatched questionnaires were returned (response rate 49.3%). About three quarters (74%) of general physicians rarely or never use cardiovascular prediction rules. Most often stated barriers to apply prediction rules among rarely- or never-users are doubts concerning over-simplification of risk assessment using these instruments (58%) and potential risk of (medical) over-treatment (54%). 57% report that the numerical information resulting from prediction rules is often not helpful for decision-making in practice. CONCLUSION: If regular application of cardiovascular prediction rules in primary care is in demand additional interventions are needed to increase acceptance of these tools for patient management among general physicians

    Intervenção em saúde aos portadores de hipertensão arterial e diabetes mellitus pela ESF São Pedro 1 em Governador Valadares - MG

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    A cidade de Governador Valadares possui 41 equipes de Estratégia Saúde da Família (ESF), dentre elas a ESF São Pedro 1, com alta prevalência de hipertensos e diabéticos na área de abrangência, necessitando de acompanhamento multiprofissional contínuo. A Hipertensão Arterial Sistêmica (HAS) e o Diabetes Mellitus (DM) são duas condições de saúde de alta morbimortalidade e muito prevalentes em saúde pública, especialmente na atenção primária à saúde (APS), sendo desafio constante para os profissionais que trabalham nas unidades básicas de saúde. A prevenção, o diagnóstico, o controle e a reabilitação das condições crônicas fazem parte das funções da APS. Pelo caráter multifatorial no acompanhamento da HAS e DM deve-se buscar um trabalho multidisciplinar e multiprofissional para o bom controle individual e coletivo destas doenças. Este estudo pretende demonstrar a importância da atuação de uma equipe multiprofissional dentro de uma unidade de APS no controle da HAS e DM através da criação de uma agenda específica e grupo operativo para o atendimento destes pacientes

    An Image-Based High-Content Screening Assay for Compounds Targeting Intracellular Leishmania donovani Amastigotes in Human Macrophages

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    Leishmaniasis is a tropical disease threatening 350 million people from endemic regions. The available drugs for treatment are inadequate, with limitations such as serious side effects, parasite resistance or high cost. Driven by this need for new drugs, we developed a high-content, high-throughput image-based screening assay targeting the intracellular amastigote stage of different species of Leishmania in infected human macrophages. The in vitro infection protocol was adapted to a 384-well-plate format, enabling acquisition of a large amount of readouts by automated confocal microscopy. The reading method was based on DNA staining and required the development of a customized algorithm to analyze the images, which enabled the use of non-modified parasites. The automated analysis generated parameters used to quantify compound activity, including infection ratio as well as the number of intracellular amastigote parasites and yielded cytotoxicity information based on the number of host cells. Comparison of this assay with one that used the promastigote form to screen 26,500 compounds showed that 50% of the hits selected against the intracellular amastigote were not selected in the promastigote screening. These data corroborate the idea that the intracellular amastigote form of the parasite is the most appropriate to be used in primary screening assay for Leishmania

    Using a Non-Image-Based Medium-Throughput Assay for Screening Compounds Targeting N-myristoylation in Intracellular Leishmania Amastigotes

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    We have refined a medium-throughput assay to screen hit compounds for activity against N-myristoylation in intracellular amastigotes of Leishmania donovani. Using clinically-relevant stages of wild type parasites and an Alamar blue-based detection method, parasite survival following drug treatment of infected macrophages is monitored after macrophage lysis and transformation of freed amastigotes into replicative extracellular promastigotes. The latter transformation step is essential to amplify the signal for determination of parasite burden, a factor dependent on equivalent proliferation rate between samples. Validation of the assay has been achieved using the anti-leishmanial gold standard drugs, amphotericin B and miltefosine, with EC50 values correlating well with published values. This assay has been used, in parallel with enzyme activity data and direct assay on isolated extracellular amastigotes, to test lead-like and hit-like inhibitors of Leishmania Nmyristoyl transferase (NMT). These were derived both from validated in vivo inhibitors of Trypanosoma brucei NMT and a recent high-throughput screen against L. donovani NMT. Despite being a potent inhibitor of L. donovani NMT, the activity of the lead T. brucei NMT inhibitor (DDD85646) against L. donovani amastigotes is relatively poor. Encouragingly, analogues of DDD85646 show improved translation of enzyme to cellular activity. In testing the high-throughput L. donovani hits, we observed macrophage cytotoxicity with compounds from two of the four NMT-selective series identified, while all four series displayed low enzyme to cellular translation, also seen here with the T. brucei NMT inhibitors. Improvements in potency and physicochemical properties will be required to deliver attractive lead-like Leishmania NMT inhibitors

    Putting prevention into practice: qualitative study of factors that inhibit and promote preventive care by general practitioners, with a focus on elderly patients

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    <p>Abstract</p> <p>Background</p> <p>General practitioners (GPs) have a key role in providing preventive care, particularly for elderly patients. However, various factors can inhibit or promote the implementation of preventive care. In the present study, we identified and examined factors that inhibit and promote preventive care by German GPs, particularly for elderly patients, and assessed changes in physicians' attitudes toward preventive care throughout their careers.</p> <p>Methods</p> <p>A qualitative, explorative design was used to identify inhibitors and promoters of preventive care in German general medical practice. A total of 32 GPs in Berlin and Hannover were surveyed. Questions about factors that promote or inhibit implementation of preventive care and changes in physicians' perceptions of promoting and inhibiting factors throughout their careers were identified. Episodic interviews, which encouraged the reporting of anecdotes regarding daily knowledge and experiences, were analyzed using ATLAS/ti. Socio-demographic data of GPs and structural information about their offices were collected using short questionnaires. The factors identified as inhibitory or promoting were classified as being related to patients, physicians, or the healthcare system. The changes in GP attitudes toward preventive care throughout their careers were classified as personal transitions or as social and health policy transitions.</p> <p>Results</p> <p>Most of the identified barriers to preventive care were related to patients, such as a lack of motivation for making lifestyle changes and a lack of willingness to pay for preventive interventions. In addition, the healthcare system seemed to inadequately promote preventive care, mainly due to poor reimbursement for preventive care and fragmentation of care. GPs own attitudes and health habits seemed to influence the implementation of preventive care. GPs recognized their own lack of awareness of effective preventive interventions, particularly for elderly patients. GPs were motivated by positive preventive experiences, but often lacked the necessary training to counsel and support their patients.</p> <p>Conclusions</p> <p>German GPs had positive attitudes towards prevention, but the implementation of preventive care was neither systematic nor continuous. Identification and elimination of barriers to preventive care is crucial. Further research is needed to identify effective practice-based approaches to overcome these barriers.</p

    The impact of tubal ectopic pregnancy in Papua New Guinea - a retrospective case review

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    BACKGROUND: Ectopic pregnancy (EP) is an important cause of morbidity and mortality amongst women of reproductive age. Tubal EP is well described in industrialised countries, but less is known about its impact in low-resource countries, in particular in the South Pacific Region. METHODS: We undertook a retrospective review of women with tubal EP treated at a provincial referral hospital in coastal Papua New Guinea over a period of 56 months. Demographic and clinical variables were obtained from patients’ medical records and analysed. The institutional rate of tubal EP was calculated, and diagnosis and management reviewed. Potential risk factors for tubal EP were identified, and delays contributing to increased morbidity described. RESULTS: A total of 73 women had tubal EP. The institutional rate of tubal EP over the study period was 6.3 per 1,000 deliveries. There were no maternal deaths due to EP. The mean age of women was 31.5+/−5.7 years, 85% were parous, 67% were rural dwellers and 62% had a history of sub-fertility. The most commonly used diagnostic aid was culdocentesis. One third of women had clinical evidence of shock on arrival. All women with tubal EP were managed by open salpingectomy. Tubal rupture was confirmed for 48% of patients and was more common amongst rural dwellers. Forty-three percent of women had macroscopic evidence of pelvic infection. Two-thirds of patients received blood transfusions, and post-operative recovery lasted six days on average. Late presentation, lack of clinical suspicion, and delays with receiving appropriate treatments were observed. CONCLUSIONS: Tubal EP is a common gynaecological emergency in a referral hospital in coastal PNG, and causes significant morbidity, in particular amongst women residing in rural areas. Sexually transmitted infections are likely to represent the most important risk factor for tubal EP in PNG. Interventions to reduce the morbidity due to tubal EP include the prevention, detection and treatment of sexually transmitted infections, identification and reduction of barriers to prompt presentation, increasing health workers’ awareness of ectopic pregnancy, providing pregnancy test kits to rural health centres, and strengthening hospital blood transfusion services, including facilities for autotransfusion

    Screening out irrelevant cell-based models of disease

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    The common and persistent failures to translate promising preclinical drug candidates into clinical success highlight the limited effectiveness of disease models currently used in drug discovery. An apparent reluctance to explore and adopt alternative cell-and tissue-based model systems, coupled with a detachment from clinical practice during assay validation, contributes to ineffective translational research. To help address these issues and stimulate debate, here we propose a set of principles to facilitate the definition and development of disease-relevant assays, and we discuss new opportunities for exploiting the latest advances in cell-based assay technologies in drug discovery, including induced pluripotent stem cells, three-dimensional (3D) co-culture and organ-on-a-chip systems, complemented by advances in single-cell imaging and gene editing technologies. Funding to support precompetitive, multidisciplinary collaborations to develop novel preclinical models and cell-based screening technologies could have a key role in improving their clinical relevance, and ultimately increase clinical success rates

    ESCAIDE 2022: Translating the COVID-19 epidemiological situation into policies and measures: the Belgian experience

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    Background In 2008, in line with the WHO International Health Regulation, Belgium put in place a Risk Assessment Group (RAG) and a Risk Management Group (RMG) to ensure optimal health crisis management. The RAG, involving permanent (public health) experts supported by specific experts, analyses events causing possible risk to health and proposes prevention and control measures to the RMG. The RMG, composed of health authorities, decides on measures to be taken and follows-up the implementation. During the COVID-19 pandemic, the RAG provided advises on a wide range of topics. Among those, a weekly assessment of the epidemiological situation was performed to guide policy makers. We present here the method used for this assessment, and the link with recommended&nbsp;measures. &nbsp; Methods A comprehensive evaluation of the epidemiological situation was performed on a weekly basis using basic (cases, hospitalisations, testing, positivity rates, …) and supporting (waste water, nursing homes, schools, mobility, …) surveillance&nbsp;indicators. Results The first epidemiological risk assessment on COVID-19 was performed by the RAG on January 20, 2020, followed by regular updates. From August 2020 onwards, a weekly update was provided, with as of early May 2022, 87 weekly assessments done. In addition, a dynamic tool was developed to link the epidemiological situation to a risk level, using colours and/or phases. The indicators and thresholds evolved over time, depending on advancing knowledge, immunity and vaccination of the population, changes in test strategy and new&nbsp;variants. Discussion and&nbsp;conclusion The assessment by experts from different disciplines in an autonomous scientific advisory body and the classification of the risk according to different levels supported policy makers to decide on non-pharmaceutical interventions and testing strategy, at national and regional&nbsp;level.</p
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