398 research outputs found

    Permeability estimation directly from logging-while-drilling Induced Polarization data

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    n this study, we present the prediction of permeability from time domain spectral induced polarization (IP) data, measured in boreholes on undisturbed formations using the El-log logging-while-drilling technique. We collected El-log data and hydraulic properties on unconsolidated Quaternary and Miocene deposits in boreholes at three locations at a field site in Denmark, characterized by different electrical water conductivity and chemistry. The high vertical resolution of the El-log technique matches the lithological variability at the site, minimizing ambiguity in the interpretation originating from resolution issues. The permeability values were computed from IP data using a laboratory-derived empirical relationship presented in a recent study for saturated unconsolidated sediments, without any further calibration. A very good correlation, within 1 order of magnitude, was found between the IP-derived permeability estimates and those derived using grain size analyses and slug tests, with similar depth trends and permeability contrasts. Furthermore, the effect of water conductivity on the IP-derived permeability estimations was found negligible in comparison to the permeability uncertainties estimated from the inversion and the laboratory-derived empirical relationship

    Subsurface imaging of water electrical conductivity, hydraulic permeability and lithology at contaminated sites by induced polarization

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    At contaminated sites, knowledge about geology and hydraulic properties of the subsurface and extent of the contamination is needed for assessing the risk and for designing potential site remediation. In this study, we have developed a new approach for characterizing contaminated sites through time-domain spectral induced polarization. The new approach is based on: (1) spectral inversion of the induced polarization data through a reparametrization of the Cole-Cole model, which disentangles the electrolytic bulk conductivity from the surface conductivity for delineating the contamination plume; (2) estimation of hydraulic permeability directly from the inverted parameters using a laboratory-derived empirical equation without any calibration; (3) the use of the geophysical imaging results for supporting the geological modelling and planning of drilling campaigns. The new approach was tested on a data set from the Grindsted stream (Denmark), where contaminated groundwater from a factory site discharges to the stream. Two overlapping areas were covered with seven parallel 2-D profiles each, one large area of 410 m 790m(5melectrode spacing) and one detailed area of 126m 742m(2melectrode spacing). The geophysical results were complemented and validated by an extensive set of hydrologic and geologic information, including 94 estimates of hydraulic permeability obtained from slug tests and grain size analyses, 89 measurements of water electrical conductivity in groundwater, and four geological logs. On average the IP-derived and measured permeability values agreed within one order of magnitude, except for those close to boundaries between lithological layers (e.g. between sand and clay), where mismatches occurred due to the lack of vertical resolution in the geophysical imaging. An average formation factor was estimated from the correlation between the imaged bulk conductivity values and the water conductivity values measured in groundwater, in order to convert the imaging results from bulk conductivity to water conductivity. The geophysical models were actively used for supporting the geological modelling and the imaging of hydraulic permeability andwater conductivity allowed for a better discrimination of the clay/lignite lithology from the porewater conductivity. Furthermore, high water electrical conductivity values were found in a deep confined aquifer, which is separated by a low-permeability clay layer from a shallow aquifer. No contamination was expected in this part of the confined aquifer, and confirmation wells were drilled in the zone of increased water electrical conductivity derived from the geophysical results.Water samples from the new wells showed elevated concentrations of inorganic compounds responsible for the increased water electrical conductivity in the confined aquifer and high concentrations of xenobiotic organic contaminants such as chlorinated ethenes, sulfonamides and barbiturates

    Circulating endothelial progenitor cells are actively involved in the reparative mechanisms of stable ischemic myocardium

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    Background: Myocardial fibrosis (MF) is an adverse correlate of severe aortic valve stenosis (SAVS). microRNA expression modulates different pathophysiological pathways in cardiovascular disease. In particular miRNA­21, has been associated to MF due to pressure overload. Non­invasive estimation of MF, using speckle­tracking echocardiography (2D­STE), could be useful in determining early myocardial damage. Purpose: To analyze the correlation between 2D­STE parameters, MF, plasmatic and tissue miRNA­21 in SAVS. Methods: We evaluated 36 consecutive patients (75.2±8 y.o., 63% F) with SAVS and preserved ejection fraction (EF), undergoing to surgical aortic valve replacement (AVR; Euroscore II 2.28±1.13%; Logistic Euroscore: 6±4.1%). Clinical, ECG, biohumoral evaluation (including plasma miRNA­21) and a complete echocardiography, including 2D­STE, was performed before AVR. 28 patients eventually underwent AVR and, in 23 of them, a basal interventricular septum biopsy was performed. MF and tissue miRNA­21 expression (micro­dissection) were evaluated in each sample. Results: All patients with SAVS (AVAi 0.33±0.1 cm2/m2; V max 4.4±0.4 m/sec; Mean Grad. 50±9 mmHg) showed concentric hypertrophy (LVMi 147±20.7 g/m2, RWT 0.51±0.07), diastolic dysfunction and increased Valvulo­Arterial Impedance (ZVA: 5.9±2.3 mmHg/ml/m2). Despite a preserved EF (66±11%), an altered global and septal deformation (Global longitudinal strain, GLS −13±6.1; Global longitudinal strain rate, GLSr −0.8±0.2 1/sec; Global early diastolic Sr, GLSrE 1±0.35 1/sec; Septal longitudinal strain, SLS −8.6±2.8%; SL­Sr −0,6±0.1 1/sec; SL­SrE 0.6±0.29 1/sec) were observed. We found a significant association between MF and 2D­STE parameters, stroke volume and end­diastolic pressure (all p<0.05). Tissue miRNA­21 was mainly expressed in fibrous tissue than in myocardium (p<0.0001). Myocardial miRNA­21 was associated with AVAi (r=0.46; p=0.043) and cardiac index (r=0.5; p=0.02) while fibrous tissue miRNA­21 was associated to GLS (r=0.8; p=0.0003), GLSrE (r=−0.72; p=0.005), SLS (r=0.6; p=0.01), SL­Sr (r=0.54; p=0.03), SL­SrE (r=0.5; p=0.04) and PAPs (r=0.66; p=0.004). Plasma miRNA­21 was associated to MF (r=0.5; p=0.02) and septal longitudinal strain (r=0.38; p=0.037). Conclusions: In SAVS with preserved EF, MF is associated to impaired myocardial deformation. miRNA­21 has a potential pathophysiological role in fibrogenesis. Non­invasive evaluation of plasmatic miRNA­21 and 2D­STE could be useful in risk stratification, to optimize the timing of surgery in SAVS patients

    Inflammatory and Autoimmune Reactions in Atherosclerosis and Vaccine Design Informatics

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    Atherosclerosis is the leading pathological contributor to cardiovascular morbidity and mortality worldwide. As its complex pathogenesis has been gradually unwoven, the regime of treatments and therapies has increased with still much ground to cover. Active research in the past decade has attempted to develop antiatherosclerosis vaccines with some positive results. Nevertheless, it remains to develop a vaccine against atherosclerosis with high affinity, specificity, efficiency, and minimal undesirable pathology. In this review, we explore vaccine development against atherosclerosis by interpolating a number of novel findings in the fields of vascular biology, immunology, and bioinformatics. With recent technological breakthroughs, vaccine development affords precision in specifying the nature of the desired immune response—useful when addressing a disease as complex as atherosclerosis with a manifold of inflammatory and autoimmune components. Moreover, our exploration of available bioinformatic tools for epitope-based vaccine design provides a method to avoid expenditure of excess time or resources

    Clinical correlates of complicated grief among individuals with acute coronary syndromes

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    OBJECTIVE: The study aimed at exploring bereavement and complicated grief (CG) symptoms among subjects without a history of coronary heart disease (CHD) at the time of a first acute coronary syndrome (ACS) and to evaluate the relationship of CG symptoms and ACS. METHOD: Overall, 149 subjects with ACS (namely, acute myocardial infarct with or without ST-segment elevation or unstable angina), with no previous history of CHD, admitted to three cardiac intensive care units were included and evaluated by the Structured Clinical Interview for Complicated Grief (SCI-CG), Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale, and the 36-item Short-Form Health Survey (MOS-SF-36). RESULTS: Of the total sample of 149 subjects with ACS, 118 (79.2%) met criteria for DSM-5 persistent complex bereavement disorder. Among these, subjects who lost a partner, child, or sibling were older (P=0.008), less likely to be working (P=0.032), and more likely to be suffering from hypertension (P=0.021), returned higher scores on the SCI-CG (P=0.001) and developed the index ACS more frequently between 12 and 48 months after the death than those who lost a parent or another relative (P≤0.0001). The occurrence of ACS 12-48 months (P=0.019) after the loss was positively correlated with SCI-CG scores. An inverse relationship with SCI-CG scores was observed for patients who experienced ACS more than 48 months after the loss (P=0.005). The SCI-CG scores significantly predicted lower scores on the "general health" domain of MOS-SF-36 (P=0.030), as well as lower scores on "emotional well-being" domain (P=0.010). CONCLUSION: A great proportion of subjects with ACS report the loss of a loved one. Among these, the loss of a close relative and the severity of CG symptoms are associated with poorer health status. Our data corroborate previous data indicating a strong relationship between CG symptoms and severe cardiac problems

    Methods for evaluating endothelial function: a position statement from the European Society of Cardiology Working Group on Peripheral Circulation

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    The endothelium holds a pivotal role in cardiovascular health and disease. Assessment of its function was until recently limited to experimental designs due to its location. The advent of novel techniques has facilitated testing on a more detailed basis, with focus on distinct pathways. This review presents available in-vivo and ex-vivo methods for evaluating endothelial function with special focus on more recent ones. The diagnostic modalities covered include assessment of epicardial and microvascular coronary endothelial function, local vasodilation by venous occlusion plethysmography and flow-mediated dilatation, arterial pulse wave analysis and pulse amplitude tonometry, microvascular blood flow by laser Doppler flowmetry, biochemical markers and bioassays, measurement of endothelial-derived microparticles and progenitor cells, and glycocalyx measurements. Insights and practical information on the theoretical basis, methodological aspects, and clinical application in various disease states are discussed. The ability of these methods to detect endothelial dysfunction before overt cardiovascular disease manifests make them attractive clinical tools for prevention and rehabilitation

    Transvenous removal of pacing and implantable cardiac defibrillating leads using single sheath mechanical dilatation and multiple venous approaches: high success rate and safety in more than 2000 leads

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    Abstract: The aim of the present study was to describe a 10 years single-centre experience in pacing and defibrillating leads removal using an effective and safe modified mechanical dilatation technique. We developed a single mechanical dilating sheath extraction technique with multiple venous entry site approaches. We performed a venous entry site approach (VEA) in cases of exposed leads and an alternative transvenous femoral approach (TFA) combined with an internal transjugular approach (ITA) in the presence of very tight binding sites causing failure of VEA extraction or in cases of free-floating leads. We attempted to remove 2062 leads [1825 pacing and 237 implantable cardiac defibrillating (ICD) leads; 1989 exposed at the venous entry site and 73 free-floating] in 1193 consecutive patients. The VEA was effective in 1799 leads, the TFA in 28, and the ITA in 205; in the overall population, we completely removed 2032 leads (98.4%), partially removed 18 (0.9%), and failed to remove 12 leads (0.6%). Major complications were observed in eight patients (0.7%), causing three deaths (0.3%). Mechanical single sheath extraction technique with multiple venous entry site approaches is effective, safe, and with a good cost effective profile for pacing and ICD leads removal

    HAS-1 genetic polymorphism in sporadic abdominal aortic aneurysm

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    The hyaluronan synthase 1 (HAS-1) gene encodes a plasma membrane protein that synthesizes hyaluronan (HA), an extracellular matrix molecule. Accumulating evidence emphasizes the relevance of HA metabolism in an increasing number of processes of clinical interest, including abdominal aortic aneurysm (AAA). The existence of aberrant splicing variants of the HAS-1 gene could partly explain the altered extracellular matrix architecture and influence various biological functions, resulting in progressive arterial wall failure in the development of AAA. In the present study, we assessed the hypothesis that HAS-1 genetic 833A/G polymorphism could be associated with the risk of AAA by performing a case-control association study, involving AAA patients and healthy matched donors
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