The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform
Huajian Gao - One of the best experts on this subject based on the ideXlab platform.
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Epicardial prestrained confinement and residual stresses: a newly observed Heart Ventricle confinement interface.
Journal of The Royal Society Interface, 2019Co-Authors: Xiaodan Shi, Yue Liu, Katherine M. Copeland, Sara R. Mcmahan, Song Zhang, J. Ryan Butler, Yi Hong, Michael Cho, Pietro Bajona, Huajian GaoAbstract:The Heart epicardial layer, with elastin as the dominant component, has not been well investigated, specifically on how it contributes to ventricular biomechanics. In this study, we revealed and qu...
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Supplementary material from Epicardial prestrained confinement and residual stresses: a newly observed Heart Ventricle confinement interface
2019Co-Authors: Xiaodan Shi, Yue Liu, Katherine M. Copeland, Sara R. Mcmahan, Song Zhang, Yi Hong, Michael Cho, Pietro Bajona, Ryan J. Butler, Huajian GaoAbstract:The Heart epicardial layer, with elastin as the dominant component, has not been well investigated, specifically on how it contributes to ventricular biomechanics. In this study, we revealed and quantitatively assessed the overall status of prestraining and residual stresses exerted by the epicardial layer on the Heart left Ventricle (LV). During porcine Heart wall dissection, we discovered that bi-layered LV surface strips, consisting of an epicardial layer and cardiac muscle, always curled towards the epicardial side due to epicardial residual stresses. We hence developed a curling angle characterization technique to intuitively and qualitatively reveal the location-dependency and direction-dependency of epicardial residual stresses. Moreover, by combining prestrain measurement and biaxial mechanical testing, we were able to quantify the epicardial prestrains and residual stresses on the unpressurized intact LV. To investigate the potential mechanical effect of epicardial prestraining, a finite-element (FE) model has been constructed, and we demonstrate that it is the prestraining of the epicardial layer, not the epicardial layer alone, providing an additional resistance mechanism during LV diastolic expansion and ventricular wall protection by reducing myocardial stress. In short, our study on healthy, native porcine Hearts has revealed an important phenomenon—the epicardial layer, rich in elastin, acts like a prestrained ‘balloon’ that wraps around the Heart and functions as an extra confinement and protection interface. The obtained knowledge fills a gap in ventricular biomechanics and will help design novel biomimicking materials or prosthetic devices to target the maintenance/recreation of this Ventricle confinement interface
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Supplementary material from Epicardial prestrained confinement and residual stresses: a newly observed Heart Ventricle confinement interface
2019Co-Authors: Xiaodan Shi, Yue Liu, Katherine M. Copeland, Sara R. Mcmahan, Song Zhang, Yi Hong, Michael Cho, Pietro Bajona, Ryan J. Butler, Huajian GaoAbstract:The Heart epicardial layer, with elastin as the dominant component, has not been well investigated, specifically on how it contributes to ventricular biomechanics. In this study, we revealed and quantitatively assessed the overall status of prestraining and residual stresses exerted by the epicardial layer on the Heart left Ventricle (LV). During porcine Heart wall dissection, we discovered that bi-layered LV surface strips, consisting of an epicardial layer and cardiac muscle, always curled towards the epicardial side due to epicardial residual stresses. We hence developed a curling angle characterization technique to intuitively and qualitatively reveal the location-dependency and direction-dependency of epicardial residual stresses. Moreover, by combining prestrain measurement and biaxial mechanical testing, we were able to quantify the epicardial prestrains and residual stresses on the unpressurized intact LV. To investigate the potential mechanical effect of epicardial prestraining, a finite-element (FE) model has been constructed, and we demonstrate that it is the prestraining of epicardial layer, not the epicardial layer alone, providing an additional resistance mechanism during LV diastolic expansion and ventricular wall protection by reducing myocardial stress. In short, our study on healthy, native porcine Hearts has revealed an important phenomenon—the epicardial layer, rich in elastin, acts like a prestrained ‘balloon’ that wraps around the Heart and functions as an extra confinement and protection interface. The obtained knowledge fills a gap in ventricular biomechanics and will help design novel biomimicking materials or prosthetic devices to target the maintenance/recreation of this Ventricle confinement interface
Francesco S Pasqualini - One of the best experts on this subject based on the ideXlab platform.
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A tissue-engineered scale model of the Heart Ventricle
Nature Biomedical Engineering, 2018Co-Authors: Luke A Macqueen, John F. Zimmerman, Xujie Liu, Grant M Gonzalez, Christophe O Chantre, Patrick H Campbell, Josue A Goss, Francesco S Pasqualini, Sean P Sheehy, Sung-jin ParkAbstract:Laboratory studies of the Heart use cell and tissue cultures to dissect Heart function yet rely on animal models to measure pressure and volume dynamics. Here, we report tissue-engineered scale models of the human left Ventricle, made of nanofibrous scaffolds that promote native-like anisotropic myocardial tissue genesis and chamber-level contractile function. Incorporating neonatal rat ventricular myocytes or cardiomyocytes derived from human induced pluripotent stem cells, the tissue-engineered Ventricles have a diastolic chamber volume of ~500 µl (comparable to that of the native rat Ventricle and approximately 1/250 the size of the human Ventricle), and ejection fractions and contractile work 50–250 times smaller and 10^4–10^8 times smaller than the corresponding values for rodent and human Ventricles, respectively. We also measured tissue coverage and alignment, calcium-transient propagation and pressure–volume loops in the presence or absence of test compounds. Moreover, we describe an instrumented bioreactor with ventricular-assist capabilities, and provide a proof-of-concept disease model of structural arrhythmia. The model Ventricles can be evaluated with the same assays used in animal models and in clinical settings.Scale models of the human left Ventricle made of tissue-engineered nanofibrous scaffolds and primary rat cardiomyocytes or human-stem-cell-derived cardiomyocytes enable the study of contractile function and the modelling of structural arrhythmia.
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a tissue engineered scale model of the Heart Ventricle
Nature Biomedical Engineering, 2018Co-Authors: John F. Zimmerman, Luke A Macqueen, Christophe O Chantre, Francesco S Pasqualini, Sean P SheehyAbstract:Laboratory studies of the Heart use cell and tissue cultures to dissect Heart function yet rely on animal models to measure pressure and volume dynamics. Here, we report tissue-engineered scale models of the human left Ventricle, made of nanofibrous scaffolds that promote native-like anisotropic myocardial tissue genesis and chamber-level contractile function. Incorporating neonatal rat ventricular myocytes or cardiomyocytes derived from human induced pluripotent stem cells, the tissue-engineered Ventricles have a diastolic chamber volume of ~500 µl (comparable to that of the native rat Ventricle and approximately 1/250 the size of the human Ventricle), and ejection fractions and contractile work 50–250 times smaller and 104–108 times smaller than the corresponding values for rodent and human Ventricles, respectively. We also measured tissue coverage and alignment, calcium-transient propagation and pressure–volume loops in the presence or absence of test compounds. Moreover, we describe an instrumented bioreactor with ventricular-assist capabilities, and provide a proof-of-concept disease model of structural arrhythmia. The model Ventricles can be evaluated with the same assays used in animal models and in clinical settings.
D. Wierzbicka - One of the best experts on this subject based on the ideXlab platform.
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Computer assessment and modelling of left Heart Ventricle contractility based on kinetic model
Proceedings of the 22nd Annual International Conference of the IEEE Engineering in Medicine and Biology Society (Cat. No.00CH37143), 1Co-Authors: J.l. Kulikowski, M. Przytulska, D. WierzbickaAbstract:Ventricles' contractility is one of basic indicators of Heart function. A Fourier spectrum of the function describing the variations of left chamber's shape contains a useful diagnostic information about sector and time contractility pathologies. An examination of regional Ventricles' contractility leads to the detection of local cardiac dysfunctions like wall motion akinesis, diskinesis or hypokinesis. The authors present a mathematical model of left chamber shape variations within a single Heart-beating cycle. The model is given in its direct and incremental forms. The methods of model coefficients evaluation based on the investigation of a series of cardiac images is described.
Paul R. Benjamin - One of the best experts on this subject based on the ideXlab platform.
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Two types of voltage-gated K(+) currents in dissociated Heart ventricular muscle cells of the snail Lymnaea stagnalis.
Journal of neurophysiology, 1999Co-Authors: Mark Yeoman, Paul R. BenjaminAbstract:We have used a combination of current-clamp and voltage-clamp techniques to characterize the electrophysiological properties of enzymatically dissociated Lymnaea Heart Ventricle cells. Dissociated ...
D.r. Gardner - One of the best experts on this subject based on the ideXlab platform.
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A review of the electrophysiological, pharmacological and single channel properties of Heart Ventricle muscle cells in the snail Lymnaea stagnalis.
Experientia, 1992Co-Authors: B.l. Brezden, D.r. GardnerAbstract:Although a considerable body of information has accumulated describing the pharmacological properties of a wide range of molluscan muscle types, the physiological bases underlying these properties have not been thoroughly investigated. At present, little is known about the types of ion channels and their regulation in molluscan muscle cell membranes. Voltage-clamp, and more recently, patch-clamp techniques have revealed molluscan muscles possess a complex array of channel types with various pharmacological and electrophysiological properties. The gating properties of these channels and their modulation by chemical agents, however, are still poorly understood. This review summarizes some aspects of molluscan muscle function with particular reference to the Heart Ventricle muscle of the pond snail, Lymnaea stagnalis.
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A review of the electrophysiological, pharmacological and single channel properties of Heart Ventricle muscle cells in the snailLymnaea stagnalis
Experientia, 1992Co-Authors: B.l. Brezden, D.r. GardnerAbstract:Although a considerable body of information has accumulated describing the pharmacological properties of a wide range of molluscan muscle types, the physiological bases underlying these properties have not been thoroughly investigated. At present, little is known about the types of ion channels and their regulation in molluscan muscle cell membranes. Voltage-clamp, and more recently, patch-clamp techniques have revealed molluscan muscles possess a complex array of channel types with various pharmacological and electrophysiological properties. The gating properties of these channels and their modulation by chemical agents, however, are still poorly understood. This review summarizes some aspects of molluscan muscle function with particular reference to the Heart Ventricle muscle of the pond snail, Lymnaea stagnalis .
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Activation of a divalent cation-conducting channel in Heart Ventricle muscle cells of the snail Lymnaea stagnalis by the molluscan cardioactive peptide FMRFamide.
Acta biologica Hungarica, 1992Co-Authors: D.r. GardnerAbstract:Ion channels with characteristics of Ca2+ channels have been found in isolated Heart Ventricle cells of the snail Lymnaea stagnalis. Although spontaneous Ca2+ or Ba2+ currents were seen only occasionally, spontaneous inward Na+ currents were readily observed in the absence of patch pipette Ca2+ between membrane potentials of -100 mV and +20 mV. These currents were blocked by 2 mM Ni2+, 2 mM Co2+ and 10 microM Ca2+. The channels usually ceased conducting within a few minutes after seal formation with the patch pipette and could not be re-activated with depolarizing voltage steps. However, at the cell's resting potential, 10(-8) to 10(-6) M of the molluscan cardioactive peptide FMRFamide or its analogue FLRFamide2+ applied to the cell membrane away from the patch pipette, induced unitary Ba2+ currents or, in the absence of Ca2+ in the patch pipette, Na+ currents. This suggests that a secondary messenger is involved in the FMRFamide-induced activation of these channels rather than a direct activation of a channel-receptor complex by the peptide.
