2,301 research outputs found

    Contrast-enhanced micro-CT imaging in murine carotid arteries : a new protocol for computing wall shear stress

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    Background: Wall shear stress (WSS) is involved in the pathophysiology of atherosclerosis. The correlation between WSS and atherosclerosis can be investigated over time using a WSS-manipulated atherosclerotic mouse model. To determine WSS in vivo, detailed 3D geometry of the vessel network is required. However, a protocol to reconstruct 3D murine vasculature using this animal model is lacking. In this project, we evaluated the adequacy of eXIA 160, a small animal contrast agent, for assessing murine vascular network on micro-CT. Also, a protocol was established for vessel geometry segmentation and WSS analysis. Methods: A tapering cast was placed around the right common carotid artery (RCCA) of ApoE(-/-) mice (n = 8). Contrast-enhanced micro-CT was performed using eXIA 160. An innovative local threshold-based segmentation procedure was implemented to reconstruct 3D geometry of the RCCA. The reconstructed RCCA was compared to the vessel geometry using a global threshold-based segmentation method. Computational fluid dynamics was applied to compute the velocity field and WSS distribution along the RCCA. Results: eXIA 160-enhanced micro-CT allowed clear visualization and assessment of the RCCA in all eight animals. No adverse biological effects were observed from the use of eXIA 160. Segmentation using local threshold values generated more accurate RCCA geometry than the global threshold-based approach. Mouse-specific velocity data and the RCCA geometry generated 3D WSS maps with high resolution, enabling quantitative analysis of WSS. In all animals, we observed low WSS upstream of the cast. Downstream of the cast, asymmetric WSS patterns were revealed with variation in size and location between animals. Conclusions: eXIA 160 provided good contrast to reconstruct 3D vessel geometry and determine WSS patterns in the RCCA of the atherosclerotic mouse model. We established a novel local threshold-based segmentation protocol for RCCA reconstruction and WSS computation. The observed differences between animals indicate the necessity to use mouse-specific data for WSS analysis. For our future work, our protocol makes it possible to study in vivo WSS longitudinally over a growing plaque

    Advance Care Planning in the Netherlands

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    The Dutch health care system fosters a strong public health sector offering accessible generalist care including generalist palliative care. General practitioners are well positioned to conduct ACP, for example, to continue or initiate conversations after hospitalization. However, research shows that ACP conversations are often ad hoc and in frail patients, ACP is often only initiated when admitted to a nursing home by elderly care physicians who are on the staff. Tools that raise awareness of triggers to initiate ACP, screening tools, information brochures, checklists and training have been developed and implemented with funding by national programs which currently focus on implementation projects rather than or in addition to, research. The programs commonly require educational deliverables, patient and public involvement and addressing diversity in patient groups. A major challenge is how to implement ACP systematically and continuously across sectors and disciplines in a way that supports a proactive yet person-centered approach rather than an approach with an exclusive focus on medical procedures. Digital solutions can support continuity of care and communication about care plans. Solutions should fit a culture that prefers trust-based, informal deliberative approaches. This may be supported by involving disciplines other than medicine, such as nursing and spiritual caregiving, and public health approaches.</p

    Aspects determining the risk of pesticides to wild bees : risk profiles for focal crops on three continents

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    Globally, agricultural production systems are under pressure to meet multiple challenges: to sustain or increase production from the same area of land and reduce negative impacts on the environment amid uncertainties resulting from climate change. As farming systems adapt to meet these challenges, one of agriculture’s greatest assets in meeting them is nature itself. Many of the ecosystem services provided by nature – such as pollination – directly contribute to agricultural production. Beneficial insects such as pollinators may be heavily impacted by pesticides. This document makes a contribution to understanding the context of pesticide exposure of key crop pollinators – honey bees, but also wild bee species – through the development of risk profiles for cropping systems in Brazil, Kenya and the Netherlands. Risk profiles such as those showcased here can provide a qualitative evaluation of pesticide risks to bees in specific settings, and can be used to compare risks between different settings, facilitate discussion amongst stakeholders, identify gaps in information, set priorities for research, and establish priorities for risk mitigation

    Een cultuurvergelijkend onderzoek naar behandelbesluiten van artsen met betrekking tot demente verpleeghuispatie¨nten met pneumonie

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    Uit dit kwalitatieve onderzoek op basis van interviews in Nederland en in North Carolina (VS) bleek dat medische beslissingen door de arts worden beïnvloed door contextuele verschillen in de opleiding van artsen en in de structuur van de gezondheidszorg in de Verenigde Staten en Nederland. De Nederlandse artsen die verpleeghuispatiënten met dementie en pneumonie behandelden, namen actief de primaire verantwoordelijkheid voor behandelbesluiten, terwijl de Amerikaanse artsen zich passiever opstelden en zich meer voegden naar de voorkeuren van de familie, zelfs wanneer zij deze medisch niet zinvol vonden. De Nederlandse artsen kenden hun patiënten goed; zij namen hun beslissingen op basis van wat zij als het meest in overeenstemming achtten met het belang van de patiënt, terwijl Amerikaanse artsen aangaven hun patiënten in het verpleeghuis niet erg goed te kennen, omdat zij slechts beperkt tijd hadden voor contact met hen. Bij verbetering van zorg voor wilsonbekwame patiënten met een beperkte kwaliteit van leven dient rekening te worden gehouden met deze contextuele factoren en met de processen die bepalen hoe artsen zorgvoorkeuren van patiënt en familie vaststellen en bespreken

    AUTOMATED QUANTITATIVE ASSESSMENT OF CORONARY CALCIFICATION USING INTRAVASCULAR ULTRASOUND

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    Coronary calcification represents a challenge in the treatment of coronary artery disease by stent placement. It negatively affects stent expansion and has been related to future adverse cardiac events. Intravascular ultrasound (IVUS) is known for its high sensitivity in detecting coronary calcification. At present, automated quantification of calcium as detected by IVUS is not available. For this reason, we developed and validated an optimized framework for accurate automated detection and quantification of calcified plaque in coronary atherosclerosis as seen by IVUS. Calcified lesions were detected by training a supported vector classifier per IVUS A-line on manually annotated IVUS images, followed by post-processing using regional information. We applied our framework to 35 IVUS pullbacks from each of the three commonly used IVUS systems. Cross-validation accuracy for each system was >0.9, and the testing accuracy was 0.87, 0.89 and 0.89 for the three systems. Using the detection result, we propose an IVUS calcium score, based on the fraction of calcium-positive A-lines in a pullback segment, to quantify the extent of calcified plaque. The high accuracy of the proposed classifier suggests that it may provide a robust and accurate tool to assess the presence and amount of coronary calcification and, thus, may play a role in imageguided coronary interventions. (E-mail: [email protected]

    Simultaneous Morphological and Flow Imaging Enabled by Megahertz Intravascular Doppler Optical Coherence Tomography

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    We demonstrate three-dimensional intravascular flow imaging compatible with routine clinical image acquisition workflow by means of megahertz (MHz) intravascular Doppler Optical Coherence Tomography (OCT). The OCT system relies on a 1.1 mm diameter motorized imaging catheter and a 1.5 MHz Fourier Domain Mode Locked (FDML) laser. Using a post processing method to compensate the drift of the FDML laser output, we can resolve the Doppler phase shift between two adjoining OCT A-line datasets. By interpretation of the velocity field as measured around the zero phase shift, the flow direction at specific angles can be qualitatively estimated. Imaging experiments were carried out in phantoms, micro channels, and swine coronary artery in vitro at a speed of 600 frames/s. The MHz wavelength sweep rate of the OCT system allows us to directly investigate flow velocity of up to 37.5 cm/s while computationally expensive phase-unwrapping has to be applied to measure such high speed using conventional OCT system. The MHz sweep rate also enables a volumetric Doppler imaging even with a fast pullback at 40 mm/s. We present the first simultaneously recorded 3D morphological images and Doppler flow profiles. Flow pattern estimation and three-dimensional structural reconstruction of entire coronary artery are achieved using a single OCT pullback dataset

    Consensus on treatment for residents in long-term care facilities : perspectives from relatives and care staff in the PACE cross-sectional study in 6 European countries

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    Background: In long-term care facilities often many care providers are involved, which could make it difficult to reach consensus in care. This may harm the relation between care providers and can complicate care. This study aimed to describe and compare in six European countries the degree of consensus among everyone involved in care decisions, from the perspective of relatives and care staff. Another aim was to assess which factors are associated with reporting that full consensus was reached, from the perspective of care staff and relatives.Methods: In Belgium, England, Finland, Italy, the Netherlands and Poland a random sample of representative long-term care facilities reported all deaths of residents in the previous three months (n = 1707). This study included residents about whom care staff (n = 1284) and relatives (n = 790) indicated in questionnaires the degree of consensus among all involved in the decision or care process. To account for clustering on facility level, Generalized Estimating Equations were conducted to analyse the degree of consensus across countries and factors associated with full consensus.Results: Relatives indicated full consensus in more than half of the residents in all countries (NL 57.9% - EN 68%), except in Finland (40.7%). Care staff reported full consensus in 59.5% of residents in Finland to 86.1% of residents in England. Relatives more likely reported full consensus when: the resident was more comfortable or talked about treatment preferences, a care provider explained what palliative care is, family-physician communication was well perceived, their relation to the resident was other than child (compared to spouse/partner) or if they lived in Poland or Belgium (compared to Finland). Care staff more often indicated full consensus when they rated a higher comfort level of the resident, or if they lived in Italy, the Netherland, Poland or England (compared to Finland).Conclusions: In most countries the frequency of full consensus among all involved in care decisions was relatively high. Across countries care staff indicated full consensus more often and no consensus less often than relatives. Advance care planning, comfort and good communication between relatives and care professionals could play a role in achieving full consensus

    Future policy and research for advance care planning in dementia:consensus recommendations from an international Delphi panel of the European Association for Palliative Care

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    Advance care planning (ACP) is increasingly recognised in the global agenda for dementia care. The European Association for Palliative Care (EAPC) Taskforce on ACP in Dementia aimed to provide recommendations for policy initiatives and future research. We conducted a four-round Delphi study with a 33-country panel of 107 experts between September, 2021, and June, 2022, that was approved by the EAPC Board. Consensus was achieved on 11 recommendations concerning the regulation of advance directives, equity of access, and dementia-inclusive approaches and conversations to express patients' values. Identified research gaps included the need for an evidence-based dementia-specific practice model that optimises engagement and communication with people with fluctuating and impaired capacity and their families to support decision making, while also empowering people to adjust their decisions if their goals or preferences change over time. Policy gaps included insufficient health services frameworks for dementia-inclusive practice. The results highlight the need for more evidence and policy development that support inclusive ACP practice models.</p
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