[Show abstract][Hide abstract] ABSTRACT: Atrial fibrillation (AF), whether silent or symptomatic, is a frequent and severe complication of acute myocardial infarction (AMI). Asymmetric dimethylarginine (ADMA), an endogenous eNOS inhibitor, is a risk factor for endothelial dysfunction. We addressed the relationship between ADMA plasma levels and AF occurrence in AMI.
273 patients hospitalized for AMI were included. Continuous electrocardiographic monitoring (CEM) ≥48 hours was recorded and ADMA was measured by High Performance Liquid Chromatography on admission blood sample.
The incidence of silent and symptomatic AF was 39(14%) and 29 (11%), respectively. AF patients were markedly older than patients without AF (≈ 20 y). There was a trend towards higher ADMA levels in patients with symptomatic AF than in patients with silent AF or no AF (0.53 vs 0.49 and 0.49 μmol/L, respectively, p = 0.18,). After matching on age, we found that patients with symptomatic AF had a higher heart rate on admission and a higher rate of patients with LV dysfunction (28% vs. 3%, p = 0.025). Patients who developed symptomatic AF had a higher ADMA level than patients without AF (0.53 vs. 0.43 μmol/L; p = 0.001). Multivariate logistic regression analysis to estimate symptomatic AF occurrence showed that ADMA was independently associated with symptomatic AF (OR: 2.46 [1.21-5.00], p = 0.013) beyond history of AF, LVEF<40% and elevated HR.
We show that high ADMA level is associated with the occurrence of AF. Although no causative role can be concluded from our observational study, our work further supports the hypothesis that endothelial dysfunction is involved in the pathogenesis of AF in AMI.
PLoS ONE 07/2015; 10(7):e0131439. DOI:10.1371/journal.pone.0131439 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Silent atrial fibrillation (AF), assessed by continuous ECG monitoring (CEM), has recently been shown to be common in acute myocardial infarction (AMI), and associated with higher hospital mortality. However, the long-term prognosis is still unknown. We aimed to assess 1-year prognosis in patients experiencing silent AF in AMI.
All consecutive patients with AMI who were prospectively analysed by CEM during the first 48 h after admission and who survived at hospital discharge were included. Silent AF was defined as asymptomatic episodes lasting at least 30 s. Patients were followed up at 1 year for cardiovascular (CV) outcomes.
Among the 737 patients analysed, 106 (14%) developed silent AF and 32 (4%) symptomatic AF. Compared with the no-AF group, patients with silent AF were markedly older (79 vs 62 years, p<0.001), more frequently hypertensive (71% vs 49%, p<0.001) and less likely to be smokers (23% vs 37%, p<0.001). Also, they were more likely to have impaired LVEF (50% vs 55%, p<0.001). Risk factors in patients with silent AF were similar to those in patients with symptomatic AF. However, a history of stroke or AF was less frequent in silent AF than in symptomatic-AF patients (10% vs 25% and 10% vs 38%, respectively). At 1 year, CV events including hospitalisation for heart failure (HF) and CV mortality were markedly higher in silent-AF patients than in no-AF patients (6.6% vs 1.3% and 5.7% vs 2.0%, p<0.001, respectively).
Our large prospective study showed for the first time that silent AF is associated with worse 1-year prognosis after AMI. Systematic screening and specific management should be investigated in order to improve outcomes of patients after AMI.
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[Show abstract][Hide abstract] ABSTRACT: A number of liquid argon time projection chambers (LAr TPCs) are being built or are proposed for neutrino experiments on long- and short baseline beams. For these detectors, a distortion in the drift field due to geometrical or physics reasons can affect the reconstruction of the events. Depending on the TPC geometry and electric drift field intensity, this distortion could be of the same magnitude as the drift field itself. Recently, we presented a method to calibrate the drift field and correct for these possible distortions. While straight cosmic ray muon tracks could be used for calibration, multiple coulomb scattering and momentum uncertainties allow only a limited resolution. A UV laser instead can create straight ionization tracks in liquid argon, and allows one to map the drift field along different paths in the TPC inner volume. Here we present a UV laser feed-through design with a steerable UV mirror immersed in liquid argon that can point the laser beam at many locations through the TPC. The straight ionization paths are sensitive to drift field distortions, a fit of these distortion to the linear optical path allows to extract the drift field, by using these laser tracks along the whole TPC volume one can obtain a 3D drift field map. The UV laser feed-through assembly is a prototype of the system that will be used for the MicroBooNE experiment at the Fermi National Accelerator Laboratory (FNAL).
Journal of Instrumentation 11/2014; 9(11):T11007. DOI:10.1088/1748-0221/9/11/T11007 · 1.40 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The maintenance of stable extracellular and intracellular iron concentrations requires the coordinated regulation of iron transport into plasma. Iron is a fundamental cofactor for several enzymes involved in oxidation–reduction reactions. The redox ability of iron can lead to the production of oxygen free radicals, which can damage various cellular components. Therefore, the appropriate regulation of systemic iron homeostasis is decisive in vital processes. Hepcidin has emerged as the central regulatory molecule of systemic iron homeostasis. It is synthesized in hepatocytes and in other cells and released into the circulation. It inhibits the release of iron from enterocytes of the duodenum and from macrophages by binding to the iron exporter protein, ferroportin (FPN). FPN is a transmembrane protein responsible for iron export from cells into the plasma. Hepcidin is internalized with FPN and both are degraded in lysosomes. The hepcidin-FPN axis is the principal regulator of extracellular iron homeostasis in health and disease. Its manipulation via agonists and antagonists is an attractive and novel therapeutic strategy. Hepcidin agonists include compounds that mimic the activity of hepcidin and agents that increase the production of hepcidin by targeting hepcidin-regulatory molecules. The inhibition of hepcidin could be a potentially attractive therapeutic strategy in patients suffering from anaemia or chronic inflammation. In this review, we will summarize the role of hepcidin in iron homeostasis and its contribution to the pathophysiology of inflammation and iron disorders. We will examine emerging new strategies that modulate hepcidin metabolism.
[Show abstract][Hide abstract] ABSTRACT: ARGONTUBE is a liquid argon time projection chamber (TPC) with an electron
drift length of up to 5 m equipped with cryogenic charge-sensitive
preamplifiers. In this work, we present results on its performance including a
comparison of the new cryogenic charge-sensitive preamplifiers with the
previously used room-temperature-operated charge preamplifiers.
Journal of Instrumentation 08/2014; 9(11). DOI:10.1088/1748-0221/9/11/P11022 · 1.40 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective
Growth differentiation factor-15 (GDF-15) has been identified as a strong marker of cardiovascular disease; however, no data are available concerning the role of GDF-15 in the occurrence of organ dysfunction during coronary artery bypass grafting (CABG) associated with cardiopulmonary bypass (CPB).
Five arterial blood samples were taken sequentially in 34 patients from anesthesia induction (IND) until 24 h after arrival at the intensive care unit (ICU). Plasma levels of GDF-15, follistatin-like 1 (FLST1), myeloperoxidases (MPO), hydroperoxides and plasma antioxidant status (PAS) were measured at each time-point. Markers of cardiac (cardiac-troponin I, cTnI) and renal dysfunction (neutrophil gelatinase-associated lipocalin, NGAL) and other classical biological factors and clinical data were measured.
Plasma GDF-15 levels increased gradually during and after surgery, reaching nearly three times the IND levels in the ICU (3,075±284 ng/L vs. 1,061±90 ng/L, p<0.001). Plasma MPO levels increased dramatically during surgery, attaining their highest level after unclamping (UNCLAMP) (49±11 ng/mL vs. 1,679±153 ng/mL, p<0.001) while PAS significantly decreased between IND and UNCLAMP (p<0.05), confirming the high oxidative status induced by this surgical procedure. ICU levels of GDF-15 correlated positively with cTnI and NGAL (p = 0.006 and p = 0.036, respectively), and also with hemoglobin and estimated glomerular filtration rate (eGFR). Among all the post-operative biomarkers available, only eGFR, NGAL and GDF-15 measured at ICU arrival were significantly associated with the onset of acute kidney injury (AKI). Patients with a EuroSCORE >3 were shown to have higher GDF-15 levels.
During cardiac surgery associated with CPB, GDF-15 levels increased substantially and were associated with markers of cardiac injury and renal dysfunction.
PLoS ONE 08/2014; 9(8):e105759. DOI:10.1371/journal.pone.0105759 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: ARGONTUBE is a liquid argon time projection chamber (LAr TPC) with a drift
field generated in-situ by a Greinacher voltage multiplier circuit. We present
results on the measurement of the drift field distribution based on a
simplified model of a multi-stage Greinacher circuit, by using straight
ionization tracks generated by an intense UV laser beam.
Journal of Instrumentation 08/2014; 9(11). DOI:10.1088/1748-0221/9/11/P11010 · 1.40 Impact Factor