scholarly journals Multiscale FEM Modeling of Vascular Tone: From Membrane Currents to Vessel Mechanics

2011 ◽  
Vol 58 (12) ◽  
pp. 3456-3459 ◽  
Author(s):  
A. Kapela ◽  
N. M. Tsoukias
Keyword(s):  
Vascular Tone ◽  
Membrane Currents ◽  
Fem Modeling ◽  
Multiscale Fem ◽  
Vessel Mechanics

scholarly journals Multiscale model of the physiological control of myocardial perfusion to delineate putative metabolic feedback mechanisms

2021 ◽  
Author(s):  
Hamidreza Gharahi ◽  
C. Alberto Figueroa ◽  
Johnathan D. Tune ◽  
Daniel A Beard
Keyword(s):  
Experimental Data ◽  
Myocardial Perfusion ◽  
Oxygen Delivery ◽  
Vascular Tone ◽  
Control Mechanisms ◽  
Modeling Framework ◽  
Feedback Mechanisms ◽  
Mechanics Model ◽  
Metabolic Mechanism ◽  
Vessel Mechanics

Coronary blood flow is tightly regulated to ensure that myocardial oxygen delivery meets local metabolic demand via the concurrent action of myogenic, neural, and metabolic mechanisms. While several competing hypotheses exist, the specific nature of the local metabolic mechanism(s) remains poorly defined. To gain insights into the viability of putative metabolic feedback mechanisms and into the coordinated action of parallel regulatory mechanisms, we applied a multi-scale modeling framework to analyze experimental data on coronary pressure, flow, and myocardial oxygen delivery in the porcine heart in vivo. The modeling framework integrates a previously established lumped-parameter model of myocardial perfusion used to account for transmural hemodynamic variations and a simple vessel mechanics model used to simulate the vascular tone in each of three myocardial layers. Vascular tone in the resistance vessel mechanics model is governed by input stimuli from the myogenic, metabolic, and autonomic control mechanisms. Seven competing formulations of the metabolic feedback mechanism are implemented in the modeling framework, and associated model simulations are compared to experimental data on coronary pressures and flows under a range of experimental conditions designed to interrogate the governing control mechanisms. Analysis identifies a maximally likely metabolic mechanism among the seven tested models, in which production of a metabolic signaling factor is proportional to MVO2 and delivery proportional to flow. Finally, the identified model is validated based on comparisons of simulations to data on the myocardial perfusion response to conscious exercise that were not used for model identification.

Immunoelectron microscope detection of C-type natriuretic peptide in normal human atrial tissue

1993 ◽  
Vol 51 ◽  
pp. 388-389
Author(s):  
Chi-Ming Wei ◽  
Margaret Hukee ◽  
Christopher G.A. McGregor ◽  
John C. Burnett
Keyword(s):  
Amino Acid ◽  
Natriuretic Peptide ◽  
Vascular Tone ◽  
Cardiac Tissue ◽  
Ring Structure ◽  
Terminal Amino Acid ◽  
Amino Acid Peptide ◽  
Normal Human ◽  
Terminal Amino ◽  
The Brain

C-type natriuretic peptide (CNP) is a newly identified peptide that is structurally related to atrial (ANP) and brain natriuretic peptide (BNP). CNP exists as a 22-amino acid peptide and like ANP and BNP has a 17-amino acid ring formed by a disulfide bond. Unlike these two previously identified cardiac peptides, CNP lacks the COOH-terminal amino acid extension from the ring structure. ANP, BNP and CNP decrease cardiac preload, but unlike ANP and BNP, CNP is not natriuretic. While ANP and BNP have been localized to the heart, recent investigations have failed to detect CNP mRNA in the myocardium although small concentrations of CNP are detectable in the porcine myocardium. While originally localized to the brain, recent investigations have localized CNP to endothelial cells consistent with a paracrine role for CNP in the control of vascular tone. While CNP has been detected in cardiac tissue by radioimmunoassay, no studies have demonstrated CNP localization in normal human heart by immunoelectron microscopy.

Vascular adaptations to hypoxia: molecular and cellular mechanisms regulating vascular tone

2007 ◽  
Vol 43 ◽  
pp. 105-120 ◽  
Author(s):  
Michael L. Paffett ◽  
Benjimen R. Walker
Keyword(s):  
Vascular Tone ◽  
Cellular Proliferation ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Hypoxia Inducible Factor ◽  
Systemic Circulation ◽  
Cellular Mechanisms ◽  
Hypoxia Inducible Factor 1 ◽  
Pulmonary Vasoconstriction ◽  
Adaptive Mechanisms ◽  
Adaptive Processes

Several molecular and cellular adaptive mechanisms to hypoxia exist within the vasculature. Many of these processes involve oxygen sensing which is transduced into mediators of vasoconstriction in the pulmonary circulation and vasodilation in the systemic circulation. A variety of oxygen-responsive pathways, such as HIF (hypoxia-inducible factor)-1 and HOs (haem oxygenases), contribute to the overall adaptive process during hypoxia and are currently an area of intense research. Generation of ROS (reactive oxygen species) may also differentially regulate vascular tone in these circulations. Potential candidates underlying the divergent responses between the systemic and pulmonary circulations may include Nox (NADPH oxidase)-derived ROS and mitochondrial-derived ROS. In addition to alterations in ROS production governing vascular tone in the hypoxic setting, other vascular adaptations are likely to be involved. HPV (hypoxic pulmonary vasoconstriction) and CH (chronic hypoxia)-induced alterations in cellular proliferation, ionic conductances and changes in the contractile apparatus sensitivity to calcium, all occur as adaptive processes within the vasculature.

Why is a new journal dedicated to vascular biology required?

2018 ◽  
Author(s):  
Paolo Madeddu
Keyword(s):  
Myocardial Ischemia ◽  
Tumor Growth ◽  
Vascular Tone ◽  
50Th Anniversary ◽  
Vascular Biology ◽  
Active Process ◽  
Master Regulators ◽  
Relaxing Factor ◽  
Tissue Healing ◽  
Endothelium Derived Relaxing Factor

The year 2018 marked the 110th anniversary of Goldmann’s discovery that vascularization is an active process in tissues1 and the 50th anniversary of the concomitant reports from Greenblatt and Shubik2 and Ehrmann and Knoth3 that soluble morphogenic factors are required for cancer angiogenesis. Many other radically transformative paradigms have been introduced in the last decades. To name a few, the molecular search for the identity of master regulators of vascular tone led to the discovery of the Endothelium-Derived Relaxing Factor (EDRF; i.e., NO4), while clinically inspired investigations led to the recognition of the pathophysiological relevance of neoangiogenesis in cancer and tissue healing. This brought about the proposal of blocking angiogenesis to halt tumor growth and stimulating angiogenesis to treat myocardial ischemia and heart failure5-7.

Finite-Element Modeling and Quantitative Measurement Using Scanning Microwave Microscopy to Characterize Dielectric Films

2018 ◽  
Author(s):  
K. A. Rubin ◽  
W. Jolley ◽  
Y. Yang
Keyword(s):  
Thin Films ◽  
Dielectric Film ◽  
Dielectric Constants ◽  
Dielectric Films ◽  
Silicon Substrates ◽  
Fem Modeling ◽  
Dielectric Thin Films ◽  
Microwave Microscopy ◽  
Scanning Microwave Microscopy ◽  
Low K

Abstract Scanning Microwave Impedance Microscopy (sMIM) can be used to characterize dielectric thin films and to quantitatively discern film thickness differences. FEM modeling of the sMIM response provides understanding of how to connect the measured sMIM signals to the underlying properties of the dielectric film and its substrate. Modeling shows that sMIM can be used to characterize a range of dielectric film thicknesses spanning both low-k and medium-k dielectric constants. A model system consisting of SiO2 thin films of various thickness on silicon substrates is used to illustrate the technique experimentally.

Pathophysiology of Thrombosis in Peripheral Artery Disease

2020 ◽  
Vol 18 (3) ◽  
pp. 204-214 ◽  
Author(s):  
Aida Habib ◽  
Giovanna Petrucci ◽  
Bianca Rocca
Keyword(s):  
Vascular Tone ◽  
Platelet Reactivity ◽  
Coagulation Factors ◽  
Peripheral Artery ◽  
Antithrombotic Agents ◽  
Pharmacological Interventions ◽  
Physiological Conditions ◽  
Vasoactive Mediators ◽  
Artery Disease

<P>Under physiological conditions, peripheral arteries release endogenous vascular-protective and antithrombotic agents. Endothelial cells actively synthesize vasoactive mediators, which regulate vascular tone and platelet reactivity thus preventing thrombosis. Atherosclerosis disrupts homeostasis and favours thrombosis by triggering pro-thrombotic responses in the vessels, platelet activation, aggregation as well as vasoconstriction, phenomena that ultimately lead to symptomatic lumen restriction or complete occlusion. <P> In the present review, we will discuss the homeostatic role of arterial vessels in releasing vascular-protective agents, such as nitric oxide and prostacyclin, the role of pro- and anti-thrombotic vascular receptors as well as the contribution of circulating platelets and coagulation factors in triggering the pro-thrombotic response(s). We will discuss the pathological consequences of disrupting the protective pathways in the arteries and the pharmacological interventions along these pathways.</P>

scholarly journals Unique Aspects of the Developing Lung Circulation: Structural Development and Regulation of Vasomotor Tone

2016 ◽  
Vol 6 (4) ◽  
pp. 407-425 ◽  
Author(s):  
Yuangsheng Gao ◽  
David N. Cornfield ◽  
Kurt R. Stenmark ◽  
Bernard Thébaud ◽  
Steven H. Abman ◽  
...  
Keyword(s):  
Lung Development ◽  
Lung Diseases ◽  
Vascular Tone ◽  
Current Knowledge ◽  
Normal Lung ◽  
Pulmonary Vasculature ◽  
Structural Development ◽  
Vasomotor Tone ◽  
Disease States ◽  
Vasculogenesis And Angiogenesis

This review summarizes our current knowledge on lung vasculogenesis and angiogenesis during normal lung development and the regulation of fetal and postnatal pulmonary vascular tone. In comparison to that of the adult, the pulmonary circulation of the fetus and newborn displays many unique characteristics. Moreover, altered development of pulmonary vasculature plays a more prominent role in compromised pulmonary vasoreactivity than in the adult. Clinically, a better understanding of the developmental changes in pulmonary vasculature and vasomotor tone and the mechanisms that are disrupted in disease states can lead to the development of new therapies for lung diseases characterized by impaired alveolar structure and pulmonary hypertension.

Microstructure-Based FEM Modeling of Phase Transformation During Quenching of Large-Size Steel Forgings

2021 ◽  
Vol 52 (5) ◽  
pp. 1883-1900
Author(s):  
Yassine Bouissa ◽  
Muftah Zorgani ◽  
Davood Shahriari ◽  
Henri Champliaud ◽  
Jean-Benoit Morin ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Fem Modeling ◽  
Large Size
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