564 research outputs found

    Modulation of Cardiac Function: Titin Springs into Action

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    Methods for Treating Congestive Heart Failure

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    The invention features methods of treating or preventing congestive heart failure by administering a polypeptide containing an epidermal growth factor-like domain encoded by a neuregulin gene

    Methods for treating congestive heart failure

    Get PDF
    The invention features methods of treating or preventing congestive heart failure by administering a polypeptide containing an epidermal growth factor-like domain encoded by a neuregulin gene

    Methods for Treating Congestive Heart Failure

    Get PDF
    The invention features methods of treating or preventing congestive heart failure by administering a polypeptide containing an epidermal growth factor-like domain encoded by a neuregulin gene

    Inverse Design of Three-Dimensional Nanoantennas for Metasurface Applications

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    Recent advances in manufacturing techniques have been made to match the demand for high performance optical devices. To this end, tremendous research activity has been focused on optical metasurfaces as they offer a unique potential to achieve disruptive designs when paired with innovative fabrication techniques and inverse design tools. However, most metasurface designs have revolved around canonical geometries. While these elements are relatively easy to fabricate, they represent only a small portion of the design space, and rarely offer peak performance in transmission, phase range or field of view. In this work, a Lazy Ant Colony Optimization (LACO) technique is applied in conjunction with a full-wave solver using the Periodic Finite Element Boundary Integral (PFEBI) method to reveal high performing three-dimensional nanoantenna designs with potential applications for a variety of optical devices

    Titin Determines the Frank-Starling Relation in Early Diastole

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    Titin, a giant protein spanning half the sarcomere, is responsible for passive and restoring forces in cardiac myofilaments during sarcomere elongation and compression, respectively. In addition, titin has been implicated in the length-dependent activation that occurs in the stretched sarcomere, during the transition from diastole to systole. The purpose of this study was to investigate the role of titin in the length-dependent deactivation that occurs during early diastole, when the myocyte is shortened below slack length. We developed a novel in vitro assay to assess myocyte restoring force (RF) by measuring the velocity of recoil in Triton-permeabilized, unloaded rat cardiomyocytes after rigor-induced sarcomere length (SL) contractions. We compared rigor-induced SL shortening to that following calcium-induced (pCa) contractions. The RF–SL relationship was linearly correlated, and the SL-pCa curve displayed a characteristic sigmoidal curve. The role of titin was defined by treating myocytes with a low concentration of trypsin, which we show selectively degrades titin using mass spectroscopic analysis. Trypsin treatment reduced myocyte RF as shown by a decrease in the slope of the RF-SL relationship, and this was accompanied by a downward and leftward shift of the SL-pCa curve, indicative of sensitization of the myofilaments to calcium. In addition, trypsin digestion did not alter the relationship between SL and interfilament spacing (assessed by cell width) after calcium activation. These data suggest that as the sarcomere shortens below slack length, titin-based restoring forces act to desensitize the myofilaments. Furthermore, in contrast to length-dependent activation at long SLs, length-dependent deactivation does not depend on interfilament spacing. This study demonstrates for the first time the importance of titin-based restoring force in length-dependent deactivation during the early phase of diastole

    3D Co-culture of hiPSC-Derived Cardiomyocytes With Cardiac Fibroblasts Improves Tissue-Like Features of Cardiac Spheroids

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    Purpose: Both cardiomyocytes and cardiac fibroblasts (CF) play essential roles in cardiac development, function, and remodeling. Properties of 3D co-cultures are incompletely understood. Hence, 3D co-culture of cardiomyocytes and CF was characterized, and selected features compared with single-type and 2D culture conditions.Methods: Human cardiomyocytes derived from induced-pluripotent stem cells (hiPSC-CMs) were obtained from Cellular Dynamics or Ncardia, and primary human cardiac fibroblasts from ScienCell. Cardiac spheroids were investigated using cryosections and whole-mount confocal microscopy, video motion analysis, scanning-, and transmission-electron microscopy (SEM, TEM), action potential recording, and quantitative PCR (qPCR).Results: Spheroids formed in hanging drops or in non-adhesive wells showed spontaneous contractions for at least 1 month with frequent media changes. SEM of mechanically opened spheroids revealed a dense inner structure and no signs of blebbing. TEM of co-culture spheroids at 1 month showed myofibrils, intercalated disc-like structures and mitochondria. Ultrastructural features were comparable to fetal human myocardium. We then assessed immunostained 2D cultures, cryosections of spheroids, and whole-mount preparations by confocal microscopy. CF in co-culture spheroids assumed a small size and shape similar to the situation in ventricular tissue. Spheroids made only of CF and cultured for 3 weeks showed no stress fibers and strongly reduced amounts of alpha smooth muscle actin compared to early spheroids and 2D cultures as shown by confocal microscopy, western blotting, and qPCR. The addition of CF to cardiac spheroids did not lead to arrhythmogenic effects as measured by sharp-electrode electrophysiology. Video motion analysis showed a faster spontaneous contraction rate in co-culture spheroids compared to pure hiPSC-CMs, but similar contraction amplitudes and kinetics. Spontaneous contraction rates were not dependent on spheroid size. Applying increasing pacing frequencies resulted in decreasing contraction amplitudes without positive staircase effect. Gene expression analysis of selected cytoskeleton and myofibrillar proteins showed more tissue-like expression patterns in co-culture spheroids than with cardiomyocytes alone or in 2D culture.Conclusion: We demonstrate that the use of 3D co-culture of hiPSC-CMs and CF is superior over 2D culture conditions for co-culture models and more closely mimicking the native state of the myocardium with relevance to drug development as well as for personalized medicine.Peer reviewe

    Potential of vascular endothelial growth factor as a biomarker of coronary artery disease in subjects undergoing CABG surgery

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    Introduction: • Coronary artery disease (CAD) causes local hypoxia due to reduced blood flow • Hypoxic conditions are known to induce vascular endothelial growth factor (VEGF) production, a key contributor to angiogenesis • The purpose of this study was to determine the potential of VEGF as a marker of myocardial stress in subjects with CAD undergoing coronary artery bypass grafting (CABG) surger

    A criança asmática: Relação e terreno alérgico.

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    Relata-se o caso clínico de uma criança com asma alérgica. Efectua-se uma abordagem compreensiva através do modelo multidimensional de somatização proposto por Sami-Ali.ABSTRACT: Clinical report on a case study of a child with a psychosomatic disorder: bronquial asthma. The main focus of this paper is on an approach based on the Sami-Ali's somatization multidimensional model.info:eu-repo/semantics/publishedVersio

    Clinical and Research Considerations for Patients with Hypertensive Acute Heart Failure

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    Management approaches for patients in the emergency department (ED) who present with acute heart failure (AHF) have largely focused on intravenous diuretics. Yet, the primary pathophysiologic derangement underlying AHF in many patients is not solely volume overload. Patients with hypertensive AHF (H-AHF) represent a clinical phenotype with distinct pathophysiologic mechanisms that result in elevated ventricular filling pressures. To optimize treatment response and minimize adverse events in this subgroup, we propose that clinical management be tailored to a conceptual model of disease based on these mechanisms. This consensus statement reviews the relevant pathophysiology, clinical characteristics, approach to therapy, and considerations for clinical trials in ED patients with H-AHF
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