191 research outputs found

    High-impact entrepreneurs are key to overcoming the economic fallout in Europe from Covid-19

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    How can European economies recover from Covid-19? Dirk Jan van den Berg writes that as entrepreneurship takes a hit, Europe needs collaboration to develop, identify and implement innovative solutions

    High-impact entrepreneurs are key to overcoming the economic fallout from covid-19

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    As entrepreneurship takes a hit, Europe needs collaboration to develop, identify and implement innovative solutions, writes Dirk Jan van den Ber

    Von Willebrand factor and the thrombophilia of severe COVID-19: in situ evidence from autopsies

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    BACKGROUND: COVID-19 is accompanied by a hypercoagulable state and characterized by microvascular and macrovascular thrombotic complications. In plasma samples from patients with COVID-19, von Willebrand factor (VWF) levels are highly elevated and predictive of adverse outcomes, especially mortality. Yet, VWF is usually not included in routine coagulation analyses, and histologic evidence of its involvement in thrombus formation is lacking. OBJECTIVES: To determine whether VWF, an acute-phase protein, is a bystander, ie, a biomarker of endothelial dysfunction, or a causal factor in the pathogenesis of COVID-19. METHODS: We compared autopsy samples from 28 patients with lethal COVID-19 to those from matched controls and systematically assessed for VWF and platelets by immunohistochemistry. The control group comprised 24 lungs, 23 lymph nodes, and 9 hearts and did not differ significantly from the COVID-19 group in age, sex, body mass index (BMI), blood group, or anticoagulant use. RESULTS: In lungs, assessed for platelets by immunohistochemistry for CD42b, microthrombi were more frequent in patients with COVID-19 (10/28 [36%] vs 2/24 [8%]; P = .02). A completely normal pattern of VWF was rare in both groups. Accentuated endothelial staining was found in controls, while VWF-rich thrombi were only found in patients with COVID-19 (11/28 [39%] vs 0/24 [0%], respectively; P < .01), as were NETosis thrombi enriched with VWF (7/28 [25%] vs 0/24 [0%], respectively; P < .01). Forty-six percent of the patients with COVID-19 had VWF-rich thrombi, NETosis thrombi, or both. Trends were also seen in pulmonary draining lymph nodes (7/20 [35%] vs 4/24 [17%]; P = .147), where the overall presence of VWF was very high. CONCLUSION: We provide in situ evidence of VWF-rich thrombi, likely attributable to COVID-19, and suggest that VWF may be a therapeutic target in severe COVID-19

    Pupillary Responses to High-Irradiance Blue Light Correlate with Glaucoma Severity

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    PurposeTo evaluate whether a chromatic pupillometry test can be used to detect impaired function of intrinsically photosensitive retinal ganglion cells (ipRGCs) in patients with primary open-angle glaucoma (POAG) and to determine if pupillary responses correlate with optic nerve damage and visual loss.DesignCross-sectional study.ParticipantsOne hundred sixty-one healthy controls recruited from a community polyclinic (55 men; 151 ethnic Chinese) and 40 POAG patients recruited from a glaucoma clinic (22 men; 35 ethnic Chinese) 50 years of age or older.MethodsSubjects underwent monocular exposure to narrowband blue light (469 nm) or red light (631 nm) using a modified Ganzfeld dome. Each light stimulus was increased gradually over 2 minutes to activate sequentially the rods, cones, and ipRGCs that mediate the pupillary light reflex. Pupil diameter was recorded using an infrared pupillography system.Main Outcome MeasuresPupillary responses to blue light and red light were compared between control subjects and those with POAG by constructing dose-response curves across a wide range of corneal irradiances (7–14 log photons/cm2 per second). In patients with POAG, pupillary responses were evaluated relative to standard automated perimetry testing (Humphrey Visual Field [HVF]; Carl Zeiss Meditec, Dublin, CA) and scanning laser ophthalmoscopy parameters (Heidelberg Retinal Tomography [HRT]; Heidelberg Engineering, Heidelberg, Germany).ResultsThe pupillary light reflex was reduced in patients with POAG only at higher irradiance levels, corresponding to the range of activation of ipRGCs. Pupillary responses to high-irradiance blue light associated more strongly with disease severity compared with responses to red light, with a significant linear correlation observed between pupil diameter and HVF mean deviation (r = −0.44; P = 0.005) as well as HRT linear cup-to-disc ratio (r = 0.61; P < 0.001) and several other optic nerve head parameters.ConclusionsIn glaucomatous eyes, reduced pupillary responses to high-irradiance blue light were associated with greater visual field loss and optic disc cupping. In POAG, a short chromatic pupillometry test that evaluates the function of ipRGCs can be used to estimate the degree of damage to retinal ganglion cells that mediate image-forming vision. This approach could prove useful in detecting glaucoma

    Rate control efficacy in permanent atrial fibrillation:a comparison between lenient versus strict rate control in patients with and without heart failure. Background, aims, and design of RACE II

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    BACKGROUND: Recent studies demonstrated that rate control is an acceptable alternative for rhythm control in patients with persistent atrial fibrillation (AF). However, optimal heart rate during AF is still unknown. OBJECTIVE: To show that in patients with permanent AF, lenient rate control is not inferior to strict rate control in terms of cardiovascular mortality, morbidity, neurohormonal activation, New York Heart Association class for heart failure, left ventricular function, left atrial size, quality of life, and costs. METHODS: The RACE II study is a prospective multicenter trial in The Netherlands that will randomize 500 patients with permanent AF (< or = 12 months) to strict or lenient rate control. Strict rate control is defined as a mean resting heart rate < 80 beats per minute (bpm) and heart rate during minor exercise < 110 bpm. After reaching the target, a 24-hour Holter monitoring will be performed. If necessary, drug dose reduction and/or pacemaker implantation will be performed. Lenient rate control is defined as a resting heart rate < 110 bpm. Patients will be seen after 1, 2, and 3 months (for titration of rate control drugs) and yearly thereafter. We anticipate a 25% 2.5-year cardiovascular morbidity and mortality in both groups. RESULTS: Enrollment started in January 2005 in 29 centers in The Netherlands and is expected to be concluded in June 2006. Follow-up will be at least 2 years with a maximum of 3 years. CONCLUSION: This study should provide data how to treat patients with permanent AF

    Dynamic location problems with limited look-ahead

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    Background Among the most frequently encountered mutations in dilated cardiomyopathy (DCM) are those in the lamin A/C (LMNA) gene. Our goal was to analyze the LMNA gene in patients with DCM and/or conduction disease referred to the cardiogenetics outpatient clinic and to evaluate the prevalence of LMNA mutations and their clinical expression. Methods and Results The LMNA gene was screened in 61 index patients. Eleven mutations (including 6 novel) were identified, mainly in the subgroup of familial DCM with cardiac conduction disease (3/10 index patients) and in patients with DCM and Emery-Dreifuss, Limb-Girdle, or unclassified forms of muscular dystrophy (7/8 index patients). In addition, a mutation was identified in 1 of 4 families with only cardiac conduction disease. We did not identify any large deletions or duplications.Genotype-phenotype relationships revealed a high rate of sudden death and cardiac transplants in carriers of the p.N 195K mutation. Our study confirmed that the p.R225X mutation leads to cardiac conduction disease with late or no development of DCM, underscoring the importance of this mutation in putative familial "lone conduction disease." Nearly one third of LMNA mutation carriers had experienced a thromboembolic event. Conclusions This study highlights the role of LMNA mutations in DCM and related disorders. A severe phenotype in p.N 195K mutation carriers and preferential cardiac conduction disease in p.R225X carriers was encountered. Because of the clinical variability, including the development of associated symptoms in time, LMNA screening should be considered in patients with DCM or familial lone conduction diseas

    Direct Measurements of Meltwater Runoff on the Greenland Ice Sheet Surface

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    Meltwater runoff from the Greenland Ice Sheet surface influences surface mass balance (SMB), ice dynamics and global sea level rise, but is estimated with climate models and thus difficult to validate. We present a way to measure ice surface runoff directly, from hourly in situ supraglacial river discharge measurements and simultaneous high-resolution satellite/drone remote sensing of upstream fluvial catchment area. A first 72-hour trial for a 63.1 square kilometer moulin-terminating internally drained catchment (IDC) on Greenland's mid-elevation (1207-1381 meters above sea level) ablation zone is compared with melt and runoff simulations from HIRHAM5, MAR3.6.1 (Modele Atmospherique Regionale 3.6.1), RACMO2.3 (Regional Atmospheric Climate Model 2.3), MERRA-2 (Modern Era Retrospective-analysis for Research and Applications-2) and SEB climate/SMB models. Current models cannot reproduce peak discharges or timing of runoff entering moulins, but are improved using synthetic unit hydrograph theory (SUH). Retroactive SUH applications to two older field studies reproduces their findings, signifying that remotely sensed IDC area, shape, and river-length are useful for predicting delays in peak runoff delivery to moulins. Applying SUH to HIRHAM5, MAR3.6.1, RACMO2.3 gridded melt products for 799 surrounding IDCs suggests their terminal moulins receive lower peak discharges, less diurnal variability, and asynchronous runoff timing relative to climate/SMB model output alone. Conversely, large IDCs produce high moulin discharges, even at high elevations where melt rates are low. During this particular field experiment models overestimated runoff by plus 21 percent to plus 58 percent, linked to overestimated ablation and possible meltwater retention in bare, low-density ice. Direct measurements of ice surface runoff will improve climate/SMB models, and incorporating remotely sensed IDCs will aid coupling of surface mass balance with ice dynamics and subglacial systems

    Tumor biomarkers:association with heart failure outcomes

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    Background: There is increasing recognition that heart failure (HF) and cancer are conditions with a number of shared characteristics. Objectives: To explore the association between tumor biomarkers and HF outcomes. Methods: In 2,079 patients of BIOSTAT-CHF cohort, we measured six established tumor biomarkers: CA125, CA15-3, CA19-9, CEA, CYFRA 21-1, and AFP. Results: During a median follow-up of 21 months, 555 (27%) patients reached the primary endpoint of all-cause mortality. CA125, CYFRA 21-1, CEA, and CA19-9 levels were positively correlated with NT-proBNP quartiles (all P&lt;0.001, P for trend &lt;0.001), and were respectively associated with a hazard ratio of 1.17 (95% CI 1.12 – 1.23; P&lt;0.0001), 1.45 (95% CI 1.30 – 1.61; P&lt;0.0001), 1.19 (95% CI 1.09 – 1.30; P =0.006), and 1.10 (95% CI 1.05 – 1.16; P&lt;0.001)for all-cause mortality after correction for BIOSTAT risk model (age, BUN, NT-proBNP, hemoglobin, and beta-blocker). All tumor biomarkers (except AFP) had significant associations with secondary endpoints (composite of all-cause mortality and HF hospitalization, HF hospitalization, cardiovascular (CV) mortality, and non-CV mortality). ROC curves showed the AUC of CYFRA 21-1 (0.64) had a non-inferior AUC compared to NT-proBNP (0.68) for all-cause mortality (P =0.08). A combination of CYFRA 21-1 and NT-proBNP (AUC =0.71) improved the predictive value of the model for all-cause mortality (P =0.0002 compared to NT-proBNP). Conclusions: Several established tumor biomarkers showed independent associations with indices of severity of HF and independent prognostic value for HF outcomes. This demonstrates that pathophysiological pathways sensed by these tumor biomarkers are also dysregulated in HF

    Direct measurements of meltwater runoff on the Greenland ice sheet surface

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    Meltwater runoff from the Greenland ice sheet surface influences surface mass balance (SMB), ice dynamics, and global sea level rise, but is estimated with climate models and thus difficult to validate. We present a way to measure ice surface runoff directly, from hourly in situ supraglacial river discharge measurements and simultaneous high-resolution satellite/drone remote sensing of upstream fluvial catchment area. A first 72-h trial for a 63.1-km2 moulin-terminating internally drained catchment (IDC) on Greenland?s midelevation (1,207?1,381 m above sea level) ablation zone is compared with melt and runoff simulations from HIRHAM5, MAR3.6, RACMO2.3, MERRA-2, and SEB climate/SMB models. Current models cannot reproduce peak discharges or timing of runoff entering moulins but are improved using synthetic unit hydrograph (SUH) theory. Retroactive SUH applications to two older field studies reproduce their findings, signifying that remotely sensed IDC area, shape, and supraglacial river length are useful for predicting delays in peak runoff delivery to moulins. Applying SUH to HIRHAM5, MAR3.6, and RACMO2.3 gridded melt products for 799 surrounding IDCs suggests their terminal moulins receive lower peak discharges, less diurnal variability, and asynchronous runoff timing relative to climate/SMB model output alone. Conversely, large IDCs produce high moulin discharges, even at high elevations where melt rates are low. During this particular field experiment, models overestimated runoff by +21 to +58%, linked to overestimated surface ablation and possible meltwater retention in bare, porous, low-density ice. Direct measurements of ice surface runoff will improve climate/SMB models, and incorporating remotely sensed IDCs will aid coupling of SMB with ice dynamics and subglacial systemspublishersversionPeer reviewe
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