Journal articles on the topic 'Imaging-based cardiovascular fluid-structure interactions'
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bin Zakaria, Nazri Huzaimi, Mohd Zamani Ngali, and Ahmad Rivai. "Review on Fluid Structure Interaction Solution Method for Biomechanical Application." Applied Mechanics and Materials 660 (October 2014): 927–31. http://dx.doi.org/10.4028/www.scientific.net/amm.660.927.
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Fluid-Structure Interaction engages with complex geometry especially in biomechanical problem. In order to solve critical case studies such as cardiovascular diseases, we need the structure to be flexible and interact with the surrounding fluids. Thus, to simulate such systems, we have to consider both fluid and structure two-way interactions. An extra attention is needed to develop FSI algorithm in biomechanic problem, namely the algorithm to solve the governing equations, the coupling between the fluid and structural parameter and finally the algorithm for solving the grid connectivity. In this article, we will review essential works that have been done in FSI for biomechanic. Works on Navier–Stokes equations as the basis of the fluid solver and the equation of motion together with the finite element methods for the structure solver are thoroughly discussed. Important issues on the interface between structure and fluid solvers, discretised via Arbitrary Lagrangian–Eulerian grid are also pointed out. The aim is to provide a crystal clear understanding on how to develop an efficient algorithm to solve biomechanical Fluid-Structure Interaction problems in a matrix based programming platform.
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Manzoni, Andrea, and Luca Ponti. "An adjoint-based method for the numerical approximation of shape optimization problems in presence of fluid-structure interaction." ESAIM: Mathematical Modelling and Numerical Analysis 52, no. 4 (July 2018): 1501–32. http://dx.doi.org/10.1051/m2an/2017006.
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In this work, we propose both a theoretical framework and a numerical method to tackle shape optimization problems related with fluid dynamics applications in presence of fluid-structure interactions. We present a general framework relying on the solution to a suitable adjoint problem and the characterization of the shape gradient of the cost functional to be minimized. We show how to derive a system of (first-order) optimality conditions combining several tools from shape analysis and how to exploit them in order to set a numerical iterative procedure to approximate the optimal solution. We also show how to deal efficiently with shape deformations (resulting from both the fluid-structure interaction and the optimization process). As benchmark case, we consider an unsteady Stokes flow in an elastic channel with compliant walls, whose motion under the effect of the flow is described through a linear Koiter shell model. Potential applications are related e.g. to design of cardiovascular prostheses in physiological flows or design of components in aerodynamics.
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Samyn, Margaret M., Ronak Dholakia, Hongfeng Wang, Jennifer Co-Vu, Ke Yan, Michael E. Widlansky, John F. LaDisa, Pippa Simpson, and Ramin Alemzadeh. "Cardiovascular Magnetic Resonance Imaging-Based Computational Fluid Dynamics/Fluid–Structure Interaction Pilot Study to Detect Early Vascular Changes in Pediatric Patients with Type 1 Diabetes." Pediatric Cardiology 36, no. 4 (January 11, 2015): 851–61. http://dx.doi.org/10.1007/s00246-014-1071-7.
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Bracamonte, Johane H., Sarah K. Saunders, John S. Wilson, Uyen T. Truong, and Joao S. Soares. "Patient-Specific Inverse Modeling of In Vivo Cardiovascular Mechanics with Medical Image-Derived Kinematics as Input Data: Concepts, Methods, and Applications." Applied Sciences 12, no. 8 (April 14, 2022): 3954. http://dx.doi.org/10.3390/app12083954.
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Inverse modeling approaches in cardiovascular medicine are a collection of methodologies that can provide non-invasive patient-specific estimations of tissue properties, mechanical loads, and other mechanics-based risk factors using medical imaging as inputs. Its incorporation into clinical practice has the potential to improve diagnosis and treatment planning with low associated risks and costs. These methods have become available for medical applications mainly due to the continuing development of image-based kinematic techniques, the maturity of the associated theories describing cardiovascular function, and recent progress in computer science, modeling, and simulation engineering. Inverse method applications are multidisciplinary, requiring tailored solutions to the available clinical data, pathology of interest, and available computational resources. Herein, we review biomechanical modeling and simulation principles, methods of solving inverse problems, and techniques for image-based kinematic analysis. In the final section, the major advances in inverse modeling of human cardiovascular mechanics since its early development in the early 2000s are reviewed with emphasis on method-specific descriptions, results, and conclusions. We draw selected studies on healthy and diseased hearts, aortas, and pulmonary arteries achieved through the incorporation of tissue mechanics, hemodynamics, and fluid–structure interaction methods paired with patient-specific data acquired with medical imaging in inverse modeling approaches.
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Abe, Haruhiko, Giuseppe Caracciolo, Arash Kheradvar, Jagat Narula, and Partho P. Sengupta. "DETERMINANTS OF LEFT VENTRICULAR VORTEX RING CIRCULATION IN REMODELED HEARTS: IMPROVED VISUALIZATION OF CARDIAC FLUID-STRUCTURE INTERACTIONS BY ECHO CONTRAST PARTICLE IMAGING VELOCIMETRY." Journal of the American College of Cardiology 57, no. 14 (April 2011): E814. http://dx.doi.org/10.1016/s0735-1097(11)60814-0.
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Fujimoto, Shinichiro, Tomonori Kawasaki, Kanako K. Kumamaru, Yuko Kawaguchi, Tomotaka Dohi, Taichi Okonogi, Keiken Ri, et al. "Diagnostic performance of on-site computed CT-fractional flow reserve based on fluid structure interactions: comparison with invasive fractional flow reserve and instantaneous wave-free ratio." European Heart Journal - Cardiovascular Imaging 20, no. 3 (August 10, 2018): 343–52. http://dx.doi.org/10.1093/ehjci/jey104.
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Tang, Dalin, Chun Yang, Jie Zheng, Pamela K. Woodard, Jeffrey E. Saffitz, Gregorio A. Sicard, Thomas K. Pilgram, and Chun Yuan. "Quantifying Effects of Plaque Structure and Material Properties on Stress Distributions in Human Atherosclerotic Plaques Using 3D FSI Models." Journal of Biomechanical Engineering 127, no. 7 (July 29, 2005): 1185–94. http://dx.doi.org/10.1115/1.2073668.
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Background: Atherosclerotic plaques may rupture without warning and cause acute cardiovascular syndromes such as heart attack and stroke. Methods to assess plaque vulnerability noninvasively and predict possible plaque rupture are urgently needed. Method: MRI-based three-dimensional unsteady models for human atherosclerotic plaques with multi-component plaque structure and fluid-structure interactions are introduced to perform mechanical analysis for human atherosclerotic plaques. Results: Stress variations on critical sites such as a thin cap in the plaque can be 300% higher than that at other normal sites. Large calcification block considerably changes stress/strain distributions. Stiffness variations of plaque components (50% reduction or 100% increase) may affect maximal stress values by 20–50 %. Plaque cap erosion causes almost no change on maximal stress level at the cap, but leads to 50% increase in maximal strain value. Conclusions: Effects caused by atherosclerotic plaque structure, cap thickness and erosion, material properties, and pulsating pressure conditions on stress/strain distributions in the plaque are quantified by extensive computational case studies and parameter evaluations. Computational mechanical analysis has good potential to improve accuracy of plaque vulnerability assessment.
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Karantalis, Vasileios, Wayne Balkan, Ivonne H. Schulman, Konstantinos E. Hatzistergos, and Joshua M. Hare. "Cell-based therapy for prevention and reversal of myocardial remodeling." American Journal of Physiology-Heart and Circulatory Physiology 303, no. 3 (August 1, 2012): H256—H270. http://dx.doi.org/10.1152/ajpheart.00221.2012.
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Although pharmacological and interventional advances have reduced the morbidity and mortality of ischemic heart disease, there is an ongoing need for novel therapeutic strategies that prevent or reverse progressive ventricular remodeling following myocardial infarction, the process that forms the substrate for ventricular failure. The development of cell-based therapy as a strategy to repair or regenerate injured tissue offers extraordinary promise for a powerful anti-remodeling therapy. In this regard, the field of cell therapy has made major advancements in the past decade. Accumulating data from preclinical studies have provided novel insights into stem cell engraftment, differentiation, and interactions with host cellular elements, as well as the effectiveness of various methods of cell delivery and accuracy of diverse imaging modalities to assess therapeutic efficacy. These findings have in turn guided rationally designed translational clinical investigations. Collectively, there is a growing understanding of the parameters that underlie successful cell-based approaches for improving heart structure and function in ischemic and other cardiomyopathies.
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Wang, Jiaqiu, Jessica Benitez Mendieta, Phani Kumari Paritala, Yuqiao Xiang, Owen Christopher Raffel, Tim McGahan, Thomas Lloyd, and Zhiyong Li. "Case Report: Evaluating Biomechanical Risk Factors in Carotid Stenosis by Patient-Specific Fluid-Structural Interaction Biomechanical Analysis." Cerebrovascular Diseases 50, no. 3 (2021): 262–69. http://dx.doi.org/10.1159/000514138.
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<b><i>Background:</i></b> Carotid atherosclerosis is one of the main underlying inducements of stroke, which is a leading cause of disability. The morphological feature and biomechanical environment have been found to play important roles in atherosclerotic plaque progression. However, the biomechanics in each patient’s blood vessel is complicated and unique. <b><i>Method:</i></b> To analyse the biomechanical risk of the patient-specific carotid stenosis, this study used the fluid-structure interaction (FSI) computational biomechanical model. This model coupled both structural and hemodynamic analysis. Two patients with carotid stenosis planned for carotid endarterectomy were included in this study. The 3D models of carotid bifurcation were reconstructed using our in-house-developed protocol based on multisequence magnetic resonance imaging (MRI) data. Patient-specific flow and pressure waveforms were used in the computational analysis. Multiple biomechanical risk factors including structural and hemodynamic stresses were employed in post-processing to assess the plaque vulnerability. <b><i>Results:</i></b> Significant difference in morphological and biomechanical conditions between 2 patients was observed. Patient I had a large lipid core and serve stenosis at carotid bulb. The stenosis changed the cross-sectional shape of the lumen. The blood flow pattern changed consequently and led to a complex biomechanical environment. The FSI results suggested a potential plaque progression may lead to a high-risk plaque, if no proper treatment was performed. The patient II had significant tandem stenosis at both common and internal carotid artery (CCA and ICA). From the results of biomechanical factors, both stenoses had a high potential of plaque progression. Especially for the plaque at ICA branch, the current 2 small plaques might further enlarge and merge as a large vulnerable plaque. The risk of plaque rupture would also increase. <b><i>Conclusions:</i></b> Computational biomechanical analysis is a useful tool to provide the biomechanical risk factors to help clinicians assess and predict the patient-specific plaque vulnerability. The FSI computational model coupling the structural and hemodynamic computational analysis, better replicates the in vivo biomechanical condition, which can provide multiple structural and flow-based risk factors to assess plaque vulnerability.
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Vlasov, Alexey V., Nina L. Maliar, Sergey V. Bazhenov, Evelina I. Nikelshparg, Nadezda A. Brazhe, Anastasiia D. Vlasova, Stepan D. Osipov, et al. "Raman Scattering: From Structural Biology to Medical Applications." Crystals 10, no. 1 (January 15, 2020): 38. http://dx.doi.org/10.3390/cryst10010038.
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This is a review of relevant Raman spectroscopy (RS) techniques and their use in structural biology, biophysics, cells, and tissues imaging towards development of various medical diagnostic tools, drug design, and other medical applications. Classical and contemporary structural studies of different water-soluble and membrane proteins, DNA, RNA, and their interactions and behavior in different systems were analyzed in terms of applicability of RS techniques and their complementarity to other corresponding methods. We show that RS is a powerful method that links the fundamental structural biology and its medical applications in cancer, cardiovascular, neurodegenerative, atherosclerotic, and other diseases. In particular, the key roles of RS in modern technologies of structure-based drug design are the detection and imaging of membrane protein microcrystals with the help of coherent anti-Stokes Raman scattering (CARS), which would help to further the development of protein structural crystallography and would result in a number of novel high-resolution structures of membrane proteins—drug targets; and, structural studies of photoactive membrane proteins (rhodopsins, photoreceptors, etc.) for the development of new optogenetic tools. Physical background and biomedical applications of spontaneous, stimulated, resonant, and surface- and tip-enhanced RS are also discussed. All of these techniques have been extensively developed during recent several decades. A number of interesting applications of CARS, resonant, and surface-enhanced Raman spectroscopy methods are also discussed.
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van de Vosse, F. N., J. de Hart, C. H. G. A. van Oijen, D. Bessems, T. W. M. Gunther, A. Segal, B. J. B. M. Wolters, J. M. A. Stijnen, and F. P. T. Baaijens. "Finite-element-based computational methods for cardiovascular fluid-structure interaction." Journal of Engineering Mathematics 47, no. 3/4 (December 2003): 335–68. http://dx.doi.org/10.1023/b:engi.0000007985.17625.43.
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Tang, Elaine, Zhenglun (Alan) Wei, Mark A. Fogel, Alessandro Veneziani, and Ajit P. Yoganathan. "Fluid-Structure Interaction Simulation of an Intra-Atrial Fontan Connection." Biology 9, no. 12 (November 24, 2020): 412. http://dx.doi.org/10.3390/biology9120412.
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Total cavopulmonary connection (TCPC) hemodynamics has been hypothesized to be associated with long-term complications in single ventricle heart defect patients. Rigid wall assumption has been commonly used when evaluating TCPC hemodynamics using computational fluid dynamics (CFD) simulation. Previous study has evaluated impact of wall compliance on extra-cardiac TCPC hemodynamics using fluid-structure interaction (FSI) simulation. However, the impact of ignoring wall compliance on the presumably more compliant intra-atrial TCPC hemodynamics is not fully understood. To narrow this knowledge gap, this study aims to investigate impact of wall compliance on an intra-atrial TCPC hemodynamics. A patient-specific model of an intra-atrial TCPC is simulated with an FSI model. Patient-specific 3D TCPC anatomies were reconstructed from transverse cardiovascular magnetic resonance images. Patient-specific vessel flow rate from phase-contrast magnetic resonance imaging (MRI) at the Fontan pathway and the superior vena cava under resting condition were prescribed at the inlets. From the FSI simulation, the degree of wall deformation was compared with in vivo wall deformation from phase-contrast MRI data as validation of the FSI model. Then, TCPC flow structure, power loss and hepatic flow distribution (HFD) were compared between rigid wall and FSI simulation. There were differences in instantaneous pressure drop, power loss and HFD between rigid wall and FSI simulations, but no difference in the time-averaged quantities. The findings of this study support the use of a rigid wall assumption on evaluation of time-averaged intra-atrial TCPC hemodynamic metric under resting breath-held condition.
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Cai, Li, Yu Hao, Pengfei Ma, Guangyu Zhu, Xiaoyu Luo, and Hao Gao. "Fluid-structure interaction simulation of calcified aortic valve stenosis." Mathematical Biosciences and Engineering 19, no. 12 (2022): 13172–92. http://dx.doi.org/10.3934/mbe.2022616.
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<abstract><p>Calcified aortic valve stenosis (CAVS) is caused by calcium buildup and tissue thickening that impede the blood flow from left ventricle (LV) to aorta. In recent years, CAVS has become one of the most common cardiovascular diseases. Therefore, it is necessary to study the mechanics of aortic valve (AV) caused by calcification. In this paper, based on a previous idealized AV model, the hybrid immersed boundary/finite element method (IB/FE) is used to study AV dynamics and hemodynamic performance under normal and calcified conditions. The computational CAVS model is realized by dividing the AV leaflets into a calcified region and a healthy region, and each is described by a specific constitutive equation. Our results show that calcification can significantly affect AV dynamics. For example, the elasticity and mobility of the leaflets decrease due to calcification, leading to a smaller opening area with a high forward jet flow across the valve. The calcified valve also experiences an increase in local stress and strain. The increased loading due to AV stenosis further leads to a significant increase in left ventricular energy loss and transvalvular pressure gradients. The model predicted hemodynamic parameters are in general consistent with the risk classification of AV stenosis in the clinic. Therefore, mathematical models of AV with calcification have the potential to deepen our understanding of AV stenosis-induced ventricular dysfunction and facilitate the development of computational engineering-assisted medical diagnosis in AV related diseases.</p></abstract>
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Ha, Truong Sang. "A NUMERICAL INVESTIGATION OF BLOOD FLOW THROUGH THE AORTIC VALVE." Journal of Science and Technique 17, no. 5 (November 29, 2022): 16–27. http://dx.doi.org/10.56651/lqdtu.jst.v17.n05.527.
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This article aims to present a numerical analysis of blood flow in the aortic valve using fluid-structure interaction simulation. The finite element method is employed both for fluid and solid domains, and the monolithic scheme is used for the strong fluid-structure interaction coupling to solve well the two challenges: add-mass and large deformation problems. The Navier-Stokes equations are solved using the integrated method based on the unstructured grid on Arbitrary Lagrangian-Eulerian (ALE) framework with the total Lagrangian formulation is used for the non-linear behavior of the aortic valve. A smoothing technique based on the Laplace equation is employed to improve the mesh quality for both 2D and 3D geometries. The fluid characteristics, such as the velocity and pressure in the valve, are evaluated and analyzed in detail. The results show that velocity and pressure reach their maximum values when the valve is at its maximum opening. On the other hand, more vortices appear behind the valve during the closing phases. The simulation results can be used to help fully to predict and treat cardiovascular diseases.
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Yu, Yue, David Kamensky, Ming-Chen Hsu, Xin Yang Lu, Yuri Bazilevs, and Thomas J. R. Hughes. "Error estimates for projection-based dynamic augmented Lagrangian boundary condition enforcement, with application to fluid–structure interaction." Mathematical Models and Methods in Applied Sciences 28, no. 12 (November 2018): 2457–509. http://dx.doi.org/10.1142/s0218202518500537.
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In this work, we analyze the convergence of the recent numerical method for enforcing fluid–structure interaction (FSI) kinematic constraints in the immersogeometric framework for cardiovascular FSI. In the immersogeometric framework, the structure is modeled as a thin shell, and its influence on the fluid subproblem is imposed as a forcing term. This force has the interpretation of a Lagrange multiplier field supplemented by penalty forces, in an augmented Lagrangian formulation of the FSI kinematic constraints. Because of the non-matching fluid and structure discretizations used, no discrete inf-sup condition can be assumed. To avoid solving (potentially unstable) discrete saddle point problems, the penalty forces are treated implicitly and the multiplier field is updated explicitly. In the present contribution, we introduce the term dynamic augmented Lagrangian (DAL) to describe this time integration scheme. Moreover, to improve the stability and conservation of the DAL method, in a recently-proposed extension we projected the multiplier onto a coarser space and introduced the projection-based DAL method. In this paper, we formulate this projection-based DAL algorithm for a linearized parabolic model problem in a domain with an immersed Lipschitz surface, analyze the regularity of solutions to this problem, and provide error estimates for the projection-based DAL method in both the [Formula: see text] and [Formula: see text] norms. Numerical experiments indicate that the derived estimates are sharp and that the results of the model problem analysis can be extrapolated to the setting of nonlinear FSI, for which the numerical method was originally proposed.
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Takizawa, Kenji, Yuri Bazilevs, Tayfun E. Tezduyar, Christopher C. Long, Alison L. Marsden, and Kathleen Schjodt. "ST and ALE-VMS methods for patient-specific cardiovascular fluid mechanics modeling." Mathematical Models and Methods in Applied Sciences 24, no. 12 (August 15, 2014): 2437–86. http://dx.doi.org/10.1142/s0218202514500250.
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This paper provides a review of the space–time (ST) and Arbitrary Lagrangian–Eulerian (ALE) techniques developed by the first three authors' research teams for patient-specific cardiovascular fluid mechanics modeling, including fluid–structure interaction (FSI). The core methods are the ALE-based variational multiscale (ALE-VMS) method, the Deforming-Spatial-Domain/Stabilized ST formulation, and the stabilized ST FSI technique. A good number of special techniques targeting cardiovascular fluid mechanics have been developed to be used with the core methods. These include: (i) arterial-surface extraction and boundary condition techniques, (ii) techniques for using variable arterial wall thickness, (iii) methods for calculating an estimated zero-pressure arterial geometry, (iv) techniques for prestressing of the blood vessel wall, (v) mesh generation techniques for building layers of refined fluid mechanics mesh near the arterial walls, (vi) a special mapping technique for specifying the velocity profile at an inflow boundary with non-circular shape, (vii) a scaling technique for specifying a more realistic volumetric flow rate, (viii) techniques for the projection of fluid–structure interface stresses, (ix) a recipe for pre-FSI computations that improve the convergence of the FSI computations, (x) the Sequentially-Coupled Arterial FSI technique and its multiscale versions, (xi) techniques for calculation of the wall shear stress (WSS) and oscillatory shear index (OSI), (xii) methods for stent modeling and mesh generation, (xiii) methods for calculation of the particle residence time, and (xiv) methods for an estimated element-based zero-stress state for the artery. Here we provide an overview of the special techniques for WSS and OSI calculations, stent modeling and mesh generation, and calculation of the residence time with application to pulsatile ventricular assist device (PVAD). We provide references for some of the other special techniques. With results from earlier computations, we show how these core and special techniques work.
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Yang, Guang-Zhong, Robert Merrifield, Sharmeen Masood, and Philip J. Kilner. "Flow and myocardial interaction: an imaging perspective." Philosophical Transactions of the Royal Society B: Biological Sciences 362, no. 1484 (June 21, 2007): 1329–41. http://dx.doi.org/10.1098/rstb.2007.2119.
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Heart failure due to coronary artery disease has considerable morbidity and poor prognosis. An understanding of the underlying mechanics governing myocardial contraction is a prerequisite for interpreting and predicting changes induced by heart disease. Gross changes in contractile behaviour of the myocardium are readily detected with existing techniques. For more subtle changes during early stages of cardiac dysfunction, however, a sensitive method for measuring, as well as a precise criterion for quantifying, normal and impaired myocardial function is required. The purpose of this paper is to outline the role of imaging, particularly cardiovascular magnetic resonance (CMR), for investigating the fundamental relationships between cardiac morphology, function and flow. CMR is emerging as an important clinical tool owing to its safety, versatility and the high-quality images it produces that allow accurate and reproducible quantification of cardiac structure and function. We demonstrate how morphological and functional assessment of the heart can be achieved by CMR and illustrate how blood flow imaging can be used to study flow and structure interaction, particularly for elucidating the underlying haemodynamic significance of directional changes and asymmetries of the cardiac looping. Future outlook on combining imaging with engineering approaches in subject-specific biomechanical simulation is also provided.
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Guo, Jian, Liang Wang, David Monoly, Habib Samady, Jie Zheng, Xiaoya Guo, Akiko Maehara, et al. "In Vivo Intravascular Ultrasound-Based 3D Thin-Walled Model for Human Coronary Plaque Progression Study: Transforming Research to Potential Commercialization." International Journal of Computational Methods 16, no. 03 (March 17, 2019): 1842011. http://dx.doi.org/10.1142/s0219876218420112.
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Cardiovascular disease (CVD) is the leading cause of death in the world. Considerable research has been done linking various mechanical risk factors to plaque progression and rupture. However, methods transforming research results to clinical implementation are limited by time-consuming processes. In this study, a 3D thin-wall (TW) model was developed to approximate the 3D fluid–structure interaction (FSI) model to save time for clinical implementations. Results from one patient data (100 TW models) indicated that the relative errors of the average plaque wall stress (APWS) and strain were less than 7%, meanwhile the correlation results of the TW models were similar with that of the FSI models.
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Kratzke, Jonas, Michael Schick, and Vincent Heuveline. "Fluid-Structure Interaction Simulation of an Aortic Phantom with Uncertain Young's Modulus Using the Polynomial Chaos Expansion." Applied Mechanics and Materials 807 (November 2015): 34–44. http://dx.doi.org/10.4028/www.scientific.net/amm.807.34.
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To add reliability to numerical simulations, Uncertainty Quantification is considered to be a crucial tool for clinical decision making. This especially holds for risk assessment of cardiovascular surgery, for which threshold parameters computed by numerical simulations are currently being discussed. A corresponding biomechanical model includes blood flow, soft tissue deformation, as well as fluid-structure coupling. Thereby, structural material parameters have a strong impact on the dynamic behavior. In practice, however, particularly the value of the Young's modulus is rarely known in a precise way, and therefore, it reflects a natural level of uncertainty. In this work we introduce a stochastic model for representing variations in the Young's modulus and quantify its effect on the wall sheer stress and von Mises stress by means of the Polynomial Chaos method. We demonstrate the use of uncertainty quantification in this context and provide numerical results based on an aortic phantom benchmark model.
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Attaran, Seyed Hamidreza, Hanieh Niroomand-oscuii, and Farzan Ghalichi. "Local hemodynamic analysis of the C-Pulse Device by 3D fluid-structure interaction simulation." Future Cardiology 16, no. 4 (July 2020): 297–308. http://dx.doi.org/10.2217/fca-2019-0004.
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Background: C-Pulse is a new, nonblood contacting device based on the concept of counter-pulsation that is designed for long-term implantation. However, there is a lack of comprehensive investigation of the pressure and velocity fields under the action of C-Pulse. Aim: In this paper, we aim to conduct a numerical simulation of the underlying mechanism of the device in order to analyze its performance and related undesirable issues. Materials & methods: A 3D finite element model is utilized to simulate the mechanism of the blood pumping. Results & conclusion: The simulation well reproduced the essential characteristics of the C-Pulse. Preliminary results were in a reasonable range while a couple of irregular flow patterns were identified.
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Kato, Etsuro, Shinichiro Fujimoto, Kanako K. Kumamaru, Yuko O. Kawaguchi, Tomotaka Dohi, Chihiro Aoshima, Yuki Kamo, et al. "Adjustment of CT-fractional flow reserve based on fluid–structure interaction underestimation to minimize 1-year cardiac events." Heart and Vessels 35, no. 2 (August 7, 2019): 162–69. http://dx.doi.org/10.1007/s00380-019-01480-4.
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Hassani, Kamran, Alireza Karimi, Ali Dehghani, Ali Tavakoli Golpaygani, Hamed Abdi, and Daniel M. Espino. "Development of a fluid-structure interaction model to simulate mitral valve malcoaptation." Perfusion 34, no. 3 (November 3, 2018): 225–30. http://dx.doi.org/10.1177/0267659118811045.
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Object: Mitral regurgitation (MR) is a condition in which the mitral valve does not prevent the reversal of blood flow from the left ventricle into the left atrium. This study aimed at numerically developing a model to mimic MR and poor leaflet coaptation and also comparing the performance of a normal mitral valve to that of the MR conditions at different gap junctions of 1, 3 and 5 mm between the anterior and posterior leaflets. Results: The results revealed no blood flow to the left ventricle when a gap between the leaflets was 0 mm. However, MR increased this blood flow, with increases in the velocity and pressure within the atrium. However, the pressure within the aorta did not vary meaningfully (ranging from 22 kPa for a ‘healthy’ model to 25 kPa for severe MR). Conclusions: The findings from this study have implications not only for understanding the changes in pressure and velocity as a result of MR in the ventricle, atrium or aorta, but also for the development of a computational model suitable for clinical translation when diagnosing and determining treatment for MR.
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Takizawa, Kenji, Yuri Bazilevs, Tayfun E. Tezduyar, and Ming-Chen Hsu. "Computational Cardiovascular Flow Analysis with the Variational Multiscale Methods." Journal of Advanced Engineering and Computation 3, no. 2 (June 30, 2019): 366. http://dx.doi.org/10.25073/jaec.201932.245.
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Computational cardiovascular flow analysis can provide valuable information to medical doctors in a wide range of patientspecific cases, including cerebral aneurysms, aortas and heart valves. The computational challenges faced in this class of flow analyses also have a wide range. They include unsteady flows, complex cardiovascular geometries, moving boundaries and interfaces, such as the motion of the heart valve leaflets, contact between moving solid surfaces, such as the contact between the leaflets, and the fluid–structure interaction between the blood and the cardiovascular structure. Many of these challenges have been or are being addressed by the Space–Time Variational Multiscale (ST-VMS) method, Arbitrary Lagrangian–Eulerian VMS (ALE-VMS) method, and the VMS-based Immersogeometric Analysis (IMGA-VMS), which serve as the core computational methods, and the special methods used in combination with them. We provide an overview of the core and special methods and present examples of challenging computations carried out with these methods, including aorta and heart valve flow analyses. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.
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Goedemans, Laurien, Jeroen J. Bax, and Victoria Delgado. "COPD and acute myocardial infarction." European Respiratory Review 29, no. 156 (June 23, 2020): 190139. http://dx.doi.org/10.1183/16000617.0139-2019.
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COPD is strongly associated with cardiovascular disease, in particular acute myocardial infarction (AMI). Besides shared risk factors, COPD-related factors, such as systemic inflammation and hypoxia, underlie the pathophysiological interaction between COPD and AMI. The prevalence of COPD amongst AMI populations ranges from 7% to 30%, which is possibly even an underestimation due to underdiagnoses of COPD in general. Following the acute event, patients with COPD have an increased risk of mortality, heart failure and arrhythmias during follow-up. Adequate risk stratification can be performed using various imaging techniques, evaluating cardiac size and function after AMI. Conventional imaging techniques such as echocardiography and cardiac magnetic resonance imaging have already indicated impaired cardiac function in patients with COPD without known cardiovascular disease. Advanced imaging techniques such as speckle-tracking echocardiography and T1 mapping could provide more insight into cardiac structure and function after AMI and have proven to be of prognostic value. Future research is required to better understand the impact of AMI on patients with COPD in order to provide effective secondary prevention. The present article summarises the current knowledge on the pathophysiologic factors involved in the interaction between COPD and AMI, the prevalence and outcomes of AMI in patients with COPD and the role of imaging in the acute phase and risk stratification after AMI in patients with COPD.
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Wu, Xinlei, Clemens von Birgelen, Su Zhang, Daixin Ding, Jiayue Huang, and Shengxian Tu. "Simultaneous evaluation of plaque stability and ischemic potential of coronary lesions in a fluid–structure interaction analysis." International Journal of Cardiovascular Imaging 35, no. 9 (May 3, 2019): 1563–72. http://dx.doi.org/10.1007/s10554-019-01611-y.
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Lucor, Didier, and Olivier P. Le Maître. "Cardiovascular Modeling With Adapted Parametric Inference." ESAIM: Proceedings and Surveys 62 (2018): 91–107. http://dx.doi.org/10.1051/proc/201862091.
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Computational modeling of the cardiovascular system, promoted by the advance of fluid-structure interaction numerical methods, has made great progress towards the development of patient-specific numerical aids to diagnosis, risk prediction, intervention and clinical treatment. Nevertheless, the reliability of these models is inevitably impacted by rough modeling assumptions. A strong in-tegration of patient-specific data into numerical modeling is therefore needed in order to improve the accuracy of the predictions through the calibration of important physiological parameters. The Bayesian statistical framework to inverse problems is a powerful approach that relies on posterior sampling techniques, such as Markov chain Monte Carlo algorithms. The generation of samples re-quires many evaluations of the cardiovascular parameter-to-observable model. In practice, the use of a full cardiovascular numerical model is prohibitively expensive and a computational strategy based on approximations of the system response, or surrogate models, is needed to perform the data as-similation. As the support of the parameters distribution typically concentrates on a small fraction of the initial prior distribution, a worthy improvement consists in gradually adapting the surrogate model to minimize the approximation error for parameter values corresponding to high posterior den-sity. We introduce a novel numerical pathway to construct a series of polynomial surrogate models, by regression, using samples drawn from a sequence of distributions likely to converge to the posterior distribution. The approach yields substantial gains in efficiency and accuracy over direct prior-based surrogate models, as demonstrated via application to pulse wave velocities identification in a human lower limb arterial network.
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Abdul Khader, S. M., Anurag Ayachit, Raghuvir Pai, M. Zubair, K. A. Ahmed, and V. R. Rao. "Study of the Influence of Normal and High Blood Pressure on Normal and Stenosed Carotid Bifurcation Using Fluid-Structure Interaction." Applied Mechanics and Materials 315 (April 2013): 982–86. http://dx.doi.org/10.4028/www.scientific.net/amm.315.982.
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Atherosclerosis (stenosis) is a common cardiovascular disease in which the blood vessel restructures by narrowing, thickening and gets hardened due to the deposition of plaque. A detailed study of narrowing of arteries applying computational aspects which leads to better findings in order to know the underlying mechanics of development and progression of such diseases. Such kind of analysis can be a useful tool for the medical professionals to study the realistic physiological conditions. They can simulate and observe the blood flow in arteries. In the present study, a case of normal and stenosed carotid bifurcation is simulated. The models are generated in CATIA based on the clinical data obtained from a patient using Ultrasound Doppler. A transient FSI analysis considering Newtonian behavior is performed to compare the significance of High Blood Pressure (HBP) and Normal Blood Pressure (NBP) on carotid bifurcation. The FSI simulation is carried out for both HBP and NBP conditions for several pulse cycles on normal and stenosed models using ANSYS13.0 to demonstrate the changes in flow behavior at various sections of the model. The computed results agree well with clinical observations and available literature as seen in case of NBP.
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Fuss, Cristina, Julio C. Palmaz, and Eugene A. Sprague. "Fibrinogen: Structure, Function, and Surface Interactions." Journal of Vascular and Interventional Radiology 12, no. 6 (June 2001): 677–82. http://dx.doi.org/10.1016/s1051-0443(07)61437-7.
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Haslem, Landon, Jennifer M. Hays, and Franklin A. Hays. "p66Shc in Cardiovascular Pathology." Cells 11, no. 11 (June 6, 2022): 1855. http://dx.doi.org/10.3390/cells11111855.
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p66Shc is a widely expressed protein that governs a variety of cardiovascular pathologies by generating, and exacerbating, pro-apoptotic ROS signals. Here, we review p66Shc’s connections to reactive oxygen species, expression, localization, and discuss p66Shc signaling and mitochondrial functions. Emphasis is placed on recent p66Shc mitochondrial function discoveries including structure/function relationships, ROS identity and regulation, mechanistic insights, and how p66Shc-cyt c interactions can influence p66Shc mitochondrial function. Based on recent findings, a new p66Shc mitochondrial function model is also put forth wherein p66Shc acts as a rheostat that can promote or antagonize apoptosis. A discussion of how the revised p66Shc model fits previous findings in p66Shc-mediated cardiovascular pathology follows.
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Wu, Xian-Jun, Xin-Bin Zhou, Chen Chen, and Wei Mao. "Systematic Investigation of Quercetin for Treating Cardiovascular Disease Based on Network Pharmacology." Combinatorial Chemistry & High Throughput Screening 22, no. 6 (September 5, 2019): 411–20. http://dx.doi.org/10.2174/1386207322666190717124507.
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Aim and Objective: Cardiovascular disease is a serious threat to human health because of its high mortality and morbidity rates. At present, there is no effective treatment. In Southeast Asia, traditional Chinese medicine is widely used in the treatment of cardiovascular diseases. Quercetin is a flavonoid extract of Ginkgo biloba leaves. Basic experiments and clinical studies have shown that quercetin has a significant effect on the treatment of cardiovascular diseases. However, its precise mechanism is still unclear. Therefore, it is necessary to exploit the network pharmacological potential effects of quercetin on cardiovascular disease. Materials and Methods: In the present study, a novel network pharmacology strategy based on pharmacokinetic filtering, target fishing, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, compound-target-pathway network structured was performed to explore the anti- cardiovascular disease mechanism of quercetin. Results:: The outcomes showed that quercetin possesses favorable pharmacokinetic profiles, which have interactions with 47 cardiovascular disease-related targets and 12 KEGG signaling pathways to provide potential synergistic therapeutic effects. Following the construction of Compound-Target-Pathway (C-T-P) network, and the network topological feature calculation, we obtained top 10 core genes in this network which were AKT1, IL1B, TNF, IL6, JUN, CCL2, FOS, VEGFA, CXCL8, and ICAM1. KEGG pathway enrichment analysis. These indicated that quercetin produced the therapeutic effects against cardiovascular disease by systemically and holistically regulating many signaling pathways, including Fluid shear stress and atherosclerosis, AGE-RAGE signaling pathway in diabetic complications, TNF signaling pathway, MAPK signaling pathway, IL-17 signaling pathway and PI3K-Akt signaling pathway.
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Schwarz, Erica L., Luca Pegolotti, Martin R. Pfaller, and Alison L. Marsden. "Beyond CFD: Emerging methodologies for predictive simulation in cardiovascular health and disease." Biophysics Reviews 4, no. 1 (March 2023): 011301. http://dx.doi.org/10.1063/5.0109400.
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Physics-based computational models of the cardiovascular system are increasingly used to simulate hemodynamics, tissue mechanics, and physiology in evolving healthy and diseased states. While predictive models using computational fluid dynamics (CFD) originated primarily for use in surgical planning, their application now extends well beyond this purpose. In this review, we describe an increasingly wide range of modeling applications aimed at uncovering fundamental mechanisms of disease progression and development, performing model-guided design, and generating testable hypotheses to drive targeted experiments. Increasingly, models are incorporating multiple physical processes spanning a wide range of time and length scales in the heart and vasculature. With these expanded capabilities, clinical adoption of patient-specific modeling in congenital and acquired cardiovascular disease is also increasing, impacting clinical care and treatment decisions in complex congenital heart disease, coronary artery disease, vascular surgery, pulmonary artery disease, and medical device design. In support of these efforts, we discuss recent advances in modeling methodology, which are most impactful when driven by clinical needs. We describe pivotal recent developments in image processing, fluid–structure interaction, modeling under uncertainty, and reduced order modeling to enable simulations in clinically relevant timeframes. In all these areas, we argue that traditional CFD alone is insufficient to tackle increasingly complex clinical and biological problems across scales and systems. Rather, CFD should be coupled with appropriate multiscale biological, physical, and physiological models needed to produce comprehensive, impactful models of mechanobiological systems and complex clinical scenarios. With this perspective, we finally outline open problems and future challenges in the field.
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Bravo, Antonio J., Miguel Vera, Delia Madriz, Julio Contreras-Velásquez, José Chacón, Sandra Wilches-Durán, Modesto Graterol-Rivas, Daniela Riaño-Wilches, Joselyn Rojas, and Valmore Bermúdez. "3D ultrasound in cardiology." Imaging and Radiation Research 5, no. 1 (January 22, 2004): 53. http://dx.doi.org/10.24294/irr.v5i1.1748.
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Cardiovascular imaging analysis is a useful tool for the diagnosis, treatment and monitoring of cardiovascular diseases. Imaging techniques allow non-invasive quantitative assessment of cardiac function, providing morphological, functional and dynamic information. Recent technological advances in ultrasound have made it possible to improve the quality of patient treatment, thanks to the use of modern image processing and analysis techniques. However, the acquisition of these dynamic three-dimensional (3D) images leads to the production of large volumes of data to process, from which cardiac structures must be extracted and analyzed during the cardiac cycle. Extraction, three-dimensional visualization, and qualification tools are currently used within the clinical routine, but unfortunately require significant interaction with the physician. These elements justify the development of new efficient and robust algorithms for structure extraction and cardiac motion estimation from three-dimensional images. As a result, making available to clinicians new means to accurately assess cardiac anatomy and function from three-dimensional images represents a definite advance in the investigation of a complete description of the heart from a single examination. The aim of this article is to show what advances have been made in 3D cardiac imaging by ultrasound and additionally to observe which areas have been studied under this imaging modality.
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Hudson, J. N., P. Buckley, and I. C. McMillen. "LINKING CARDIOVASCULAR THEORY TO PRACTICE IN AN UNDERGRADUATE MEDICAL CURRICULUM." Advances in Physiology Education 25, no. 4 (December 2001): 193–201. http://dx.doi.org/10.1152/advances.2001.25.4.193.
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Case-based teaching (CBT) tutorials were introduced by the Physiology Department at Adelaide University to bridge the gap between theory and practice in the early years of undergraduate medical education. With the use of a clinical case-based environment, CBT aimed to achieve integration of structure-function relationships and an increase in students’ capacity to apply a physiological understanding to clinical observations/symptoms and data. With peer-peer interactions in small groups, students could trial history taking and examination skills, interpret common investigations, and relate their findings to an understanding of structure and function. Here, the cardiovascular tutorials highlight the centrality of an understanding of structure and function in the evaluation of a case of syncope. An independent evaluation of the students’ learning experience demonstrated that CBT tutorials were successful in their aims. The “hands-on” experience was highly rated, with students reporting that the CBT approach gave relevance to structure and function. Whatever the curriculum learning style, underpinning practice with an understanding of theory remains a desirable feature of medical education.
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Singh, Vinita, Shravali Jain, Satya Prakash, and Monika Thakur. "Studies on the synergistic Interplay of Vitamin D and K for Improving Bone and Cardiovascular Health." Current Research in Nutrition and Food Science Journal 10, no. 3 (December 20, 2022): 840–57. http://dx.doi.org/10.12944/crnfsj.10.3.3.
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Nutrients perform their roles either directly or through interaction with other nutrients inside our body. The nature of interactions between nutrients can be synergistic, which brings about maximum benefit to the host, or antagonistic, i.e., one nutrient affects the uptake and availability of other nutrients in the body. These interactions need to be critically analysed and acknowledged to harness their positive health benefits. Combining nutrients having a synergistic effect may help in lowering the threat of cardiovascular ailment, osteoporosis, and other health issues. This study aims to qualitatively review the information that is currently available upon the synergistic effects of co-supplementing Vitamin D and K on bone and cardiovascular health among various age groups. The methodology followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A structured search of two databases-PubMed and Google Scholar—was carried out, and articles were identified that focused upon the dual supplementation of Vitamin D and K, which has been shown to improve bone and cardiovascular health among users. The search was restricted to the English language, conducted, and published between 2006 and 2021. Overall, 12 studies involving 8216 participants were included in the qualitative analysis. Among these, 5 were randomized controlled trials, 6 were observational studies, and 1 was interventional studies. The results were interpreted based on improved bone health by assessing the progress in Bone Mineral Content (BMC), lower extremity function, Bone Mineral Density (BMD), and bone turnover. In contrast, improvement in cardiovascular health was recorded based on the Carotid Intima-media Thickness (CIMT), arterial stiffness, high systolic and diastolic blood pressure, and the structure of the heart. Out of a total 12 studies, 11 studies showed that Vitamin D work in synergy with Vitamin K and also has a significant role in improving bone fractures, low BMD, and cardiovascular disorders. Further research and clinical trials on these Vitamins in different age groups and disease conditions are warranted.
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BESSEMS, DAVID, MARCEL RUTTEN, and FRANS VAN DE VOSSE. "A wave propagation model of blood flow in large vessels using an approximate velocity profile function." Journal of Fluid Mechanics 580 (May 21, 2007): 145–68. http://dx.doi.org/10.1017/s0022112007005344.
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Lumped-parameter models (zero-dimensional) and wave-propagation models (one-dimensional) for pressure and flow in large vessels, as well as fully three-dimensional fluid–structure interaction models for pressure and velocity, can contribute valuably to answering physiological and patho-physiological questions that arise in the diagnostics and treatment of cardiovascular diseases. Lumped-parameter models are of importance mainly for the modelling of the complete cardiovascular system but provide little detail on local pressure and flow wave phenomena. Fully three-dimensional fluid–structure interaction models consume a large amount of computer time and must be provided with suitable boundary conditions that are often not known. One-dimensional wave-propagation models in the frequency and time domain are well suited to obtaining clinically relevant information on local pressure and flow waves travelling through the arterial system. They can also be used to provide boundary conditions for fully three-dimensional models, provided that they are defined in, or transferred to, the time domain.Most of the one-dimensional wave propagation models in the time domain described in the literature assume velocity profiles and therefore frictional forces to be in phase with the flow, whereas from exact solutions in the frequency domain a phase difference between the flow and the wall shear stress is known to exist. In this study an approximate velocity profile function more suitable for one-dimensional wave propagation is introduced and evaluated. It will be shown that this profile function provides first-order approximations for the wall shear stress and the nonlinear term in the momentum equation, as a function of local flow and pressure gradient in the time domain. The convective term as well as the approximate friction term are compared to their counterparts obtained from Womersley profiles and show good agreement in the complete range of the Womersley parameter α. In the limiting cases, for Womersley parameters α → 0 and α → ∞, they completely coincide. It is shown that in one-dimensional wave propagation, the friction term based on the newly introduced approximate profile function is important when considering pressure and flow wave propagation in intermediate-sized vessels.
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Mitchell, J. B., M. D. Phillips, S. P. Mercer, H. L. Baylies, and F. X. Pizza. "Postexercise rehydration: effect of Na+ and volume on restoration of fluid spaces and cardiovascular function." Journal of Applied Physiology 89, no. 4 (October 1, 2000): 1302–9. http://dx.doi.org/10.1152/jappl.2000.89.4.1302.
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Our purpose was to study the interaction between Na+ content and fluid volume on rehydration (RH) and restoration of fluid spaces and cardiovascular (CV) function. Ten men completed four trials in which they exercised in a 35°C environment until dehydrated by 2.9% body mass, were rehydrated for 180 min, and exercised for an additional 20 min. Four RH regimens were tested: low volume (100% fluid replacement)-low (25 mM) Na+ (LL), low volume-high (50 mM) Na+ (LH), high volume (150% fluid replacement)-low Na+ (HL), and high volume-high Na+ (HH). Blood and urine samples were collected and body mass was measured before and after exercise and every hour during RH. Before and after the dehydration exercise and during the 20 min of exercise after RH, cardiac output was measured. Fluid compartment (intracellular and extracellular) restoration and percent change in plasma volume were calculated using the Cl− and hematocrit/Hb methods, respectively. RH was greater ( P < 0.05) in HL and HH (102.0 ± 15.2 and 103.7 ± 14.7%, respectively) than in LL and LH (70.7 ± 10.5 and 75.9 ± 6.3%, respectively). Intracellular RH was greater in HL (1.12 ± 0.4 liters) than in all other conditions (0.83 ± 0.3, 0.69 ± 0.2, and 0.73 ± 0.3 liter for LL, LH, and HH, respectively), whereas extracellular RH (including plasma volume) was greater in HL and HH (1.35 ± 0.8 and 1.63 ± 0.4 liters, respectively) than in LL and LH (0.83 ± 0.3 and 1.05 ± 0.4 liters, respectively). CV function (based on stroke volume, heart rate, and cardiac output) was restored equally in all conditions. These data indicate that greater RH can be achieved through larger volumes of fluid and is not affected by Na+content within the range tested. Higher Na+ content favors extracellular fluid filling, whereas intracellular fluid benefits from higher volumes of fluid with lower Na+. Alterations in Na+ and/or volume within the range tested do not affect the degree of restoration of CV function.
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Ravi, Chandni, and Daniel W. Johnson. "Optimizing Fluid Resuscitation and Preventing Fluid Overload in Patients with Septic Shock." Seminars in Respiratory and Critical Care Medicine 42, no. 05 (September 20, 2021): 698–705. http://dx.doi.org/10.1055/s-0041-1733898.
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AbstractIntravenous fluid administration remains an important component in the care of patients with septic shock. A common error in the treatment of septic shock is the use of excessive fluid in an effort to overcome both hypovolemia and vasoplegia. While fluids are necessary to help correct the intravascular depletion, vasopressors should be concomitantly administered to address vasoplegia. Excessive fluid administration is associated with worse outcomes in septic shock, so great care should be taken when deciding how much fluid to give these vulnerable patients. Simple or strict “recipes” which mandate an exact amount of fluid to administer, even when weight based, are not associated with better outcomes and therefore should be avoided. Determining the correct amount of fluid requires the clinician to repeatedly assess and consider multiple variables, including the fluid deficit, organ dysfunction, tolerance of additional fluid, and overall trajectory of the shock state. Dynamic indices, often involving the interaction between the cardiovascular and respiratory systems, appear to be superior to traditional static indices such as central venous pressure for assessing fluid responsiveness. Point-of-care ultrasound offers the bedside clinician a multitude of applications which are useful in determining fluid administration in septic shock. In summary, prevention of fluid overload in septic shock patients is extremely important, and requires the careful attention of the entire critical care team.
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Weusthoff, Sarah, Garren Gaut, Mark Steyvers, David C. Atkins, Kurt Hahlweg, Jasara Hogan, Tanja Zimmermann, et al. "The language of interpersonal interaction: An interdisciplinary approach to assessing and processing vocal and speech data." European Journal of Counselling Psychology 7, no. 1 (September 17, 2018): 69–85. http://dx.doi.org/10.5964/ejcop.v7i1.82.
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Verbal and non-verbal information is central to social interaction between humans and has been studied intensively in psychology. Especially, dyadic interactions (e.g. between romantic partners or between psychotherapist and patient) are relevant for a number of psychological research areas. However, psychological methods applied so far have not been able to handle the vast amount of data resulting from human interactions, impeding scientific discovery and progress. This paper presents an interdisciplinary approach using technology from engineering and computer science to work with continuous data from human communication and interaction on the verbal (e.g. use of words, content) and non-verbal (e.g. vocal features of the human voice) level. Text-mining techniques such as topic models take into account the semantic and syntactic information of written text (such as therapy session transcripts) and its structure and intercorrelations. Speech signal processing focuses on the vocal information in a speaker’s voice (e.g. based on audio- or videotaped interactions). For both areas, an introduction defining the respective method and related procedures, and sample applications from psychological publications complementing or generating behavioral codes (e.g. in addition to cardiovascular indices of arousal or as a form to encode empathy) are provided. We close with a summary on the opportunities and challenges of learning and applying tools from the novel approaches described in this manuscript to different areas of psychological research and provide the interested reader with a list of additional readings on the technical aspects of topic modeling and speech signal processing.
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Cho, Soohyun, Yu-Hsiang Ling, Mi Ji Lee, Shih-Pin Chen, Jong-Ling Fuh, Jiing-Feng Lirng, Jihoon Cha, Yen-Feng Wang, Shuu-Jiun Wang, and Chin-Sang Chung. "Temporal Profile of Blood-Brain Barrier Breakdown in Reversible Cerebral Vasoconstriction Syndrome." Stroke 51, no. 5 (May 2020): 1451–57. http://dx.doi.org/10.1161/strokeaha.119.028656.
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Background and Purpose— Reversible cerebral vasoconstriction syndrome (RCVS) has a unique temporal course of vasoconstriction. Blood-brain barrier (BBB) breakdown is part of the pathophysiology of RCVS, but its temporal course is unknown. We aimed to investigate the temporal profile of BBB breakdown and relevant clinical profiles in a large sample size. Methods— In this prospective observatory bicenter study, patients who underwent contrast-enhanced fluid-attenuated inversion recovery magnetic resonance imaging within 2 months from onset were included. The presence and extent of BBB breakdown were evaluated using contrast-enhanced fluid-attenuated inversion recovery magnetic resonance imaging. Contrast-enhanced fluid-attenuated inversion recovery magnetic resonance imaging data were analyzed using a semiautomated segmentation technique to quantitatively measure the area of Gadolinium leakage into cerebrospinal fluid space. The univariable and multivariable linear regressions were performed to investigate the independent effect of time from onset with adjustment for other covariates. Results— In the 186 patients with angiogram-proven RCVS included in this analysis, BBB breakdown was observed in 52.6%, 56.8%, 30.3%, 40.0%, and 23.8% in the first, second, third, fourth, and ≥fifth week after onset. The extent of BBB breakdown peaked at first and second week, whereas the peak of vasoconstriction was observed at the third week after onset. Multivariable analysis showed the second week from onset (β, 3.35 [95% CI, 0.07–6.64]; P =0.046) and blood pressure surge (β, 3.84 [95% CI, 1.75–5.92]; P <0.001) were independently associated with a greater extent of BBB breakdown. A synergistic effect of time from onset and blood pressure surge was found ( P for interaction=0.006). Conclusions— Frequency and extent of BBB breakdown are more prominent during the early stage in patients with RCVS, with an earlier peak than that of vasoconstriction. The temporal course of BBB breakdown may provide a pathophysiologic background of the temporal course of neurological complications of RCVS.
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Ighodaro, Eseosa T., Jonathan Graff-Radford, Jeremy A. Syrjanen, Hai H. Bui, Ronald C. Petersen, David S. Knopman, Clifford R. Jack, Samantha M. Zuk, Prashanthi Vemuri, and Michelle M. Mielke. "Associations Between Plasma Ceramides and Cerebral Microbleeds or Lacunes." Arteriosclerosis, Thrombosis, and Vascular Biology 40, no. 11 (November 2020): 2785–93. http://dx.doi.org/10.1161/atvbaha.120.314796.
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Objective: High plasma ceramide levels and ratios are associated with poor outcomes in individuals with cardiovascular disease; less is known about their relation to cerebral small vessel disease. We examined whether high plasma ceramide levels or ratios were associated with cerebral microbleeds (CMBs) and lacunes and whether associations differ by sex. Approach and Results: We included 548 participants enrolled in the MCSA (Mayo Clinic Study of Aging) with concurrent plasma ceramide assays and magnetic resonance imaging. CMBs were quantified on T2* magnetic resonance imaging and lacunes on T2 fluid-attenuated inversion recovery magnetic resonance imaging. Fasting plasma ceramides were assayed using liquid chromatography-electrospray ionization tandem mass spectrometry. We used logistic regression models adjusting for age, sex, hypertension, and diabetes mellitus to examine the relationship between ceramides and presence of a lacune; hurdle models were used for presence and number of CMBs. Each SD increase in the log ceramide C16:0/24:0 ratio was associated with greater odds of a CMB (odds ratio, 1.28 [95% CI, 1.01–1.64]). There was an interaction between sex and the ceramide C16:0/24:0 ratio ( P =0.049). The association between this ratio and presence of a CMB was stronger for women (odds ratio, 1.87 [95% CI, 1.20–3.00]) than men (odds ratio, 1.09 [95% CI, 0.80–1.46]). Several ceramides and all ceramide ratios were associated with number of CMBs. We did not find associations between plasma ceramides and lacunes. Conclusions: In a population-based sample, the plasma ceramide C16:0/24:0 ratio was associated with CMBs and was stronger for women. Plasma ceramides are differentially associated with cerebral small vessel pathologies.
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Kamenskiy, Alexey V., Iraklis I. Pipinos, Yuris A. Dzenis, Prateek K. Gupta, Syed A. Jaffar Kazmi, and Jason N. MacTaggart. "A mathematical evaluation of hemodynamic parameters after carotid eversion and conventional patch angioplasty." American Journal of Physiology-Heart and Circulatory Physiology 305, no. 5 (September 1, 2013): H716—H724. http://dx.doi.org/10.1152/ajpheart.00034.2013.
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Carotid endarterectomy has a long history in stroke prevention, yet controversy remains concerning optimal techniques. Two methods frequently used are endarterectomy with patch angioplasty (CEAP) and eversion endarterectomy (CEE). The objective of this study was to compare hemodynamics-related stress and strain distributions between arteries repaired using CEAP and CEE. Mathematical models were based on in vivo three-dimensional arterial geometry, pulsatile velocity profiles, and intraluminal pressure inputs obtained from 16 patients with carotid artery disease. These data were combined with experimentally derived nonlinear, anisotropic carotid artery mechanical properties to create fluid-structure interaction models of CEAP and CEE. These models were then used to calculate hemodynamic parameters thought to promote recurrent disease and restenosis. Combining calculations of stress and strain into a composite risk index, called the integral abnormality factor, allowed for an overall comparison between CEAP and CEE. CEE demonstrated lower mechanical stresses in the arterial wall, whereas CEAP straightened the artery and caused high stress and strain concentrations at the suture-artery interface. CEAP produced a larger continuous region of oscillatory, low-shear, vortical flow in the carotid bulb. There was a more than two-fold difference in the integral abnormality factor, favoring CEE. In conclusion, in a realistically simulated carotid artery, fluid-structure interaction modeling demonstrated CEE to produce less mechanical wall stress and improved flow patterns compared with CEAP. Clinical validation with larger numbers of individual patients will ultimately be required to support modeling approaches to help predict arterial disease progression and comparative effectiveness of reconstruction methods and devices.
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Torres, Manuel, Sebastià Parets, Javier Fernández-Díaz, Roberto Beteta-Göbel, Raquel Rodríguez-Lorca, Ramón Román, Victoria Lladó, Catalina A. Rosselló, Paula Fernández-García, and Pablo V. Escribá. "Lipids in Pathophysiology and Development of the Membrane Lipid Therapy: New Bioactive Lipids." Membranes 11, no. 12 (November 24, 2021): 919. http://dx.doi.org/10.3390/membranes11120919.
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Membranes are mainly composed of a lipid bilayer and proteins, constituting a checkpoint for the entry and passage of signals and other molecules. Their composition can be modulated by diet, pathophysiological processes, and nutritional/pharmaceutical interventions. In addition to their use as an energy source, lipids have important structural and functional roles, e.g., fatty acyl moieties in phospholipids have distinct impacts on human health depending on their saturation, carbon length, and isometry. These and other membrane lipids have quite specific effects on the lipid bilayer structure, which regulates the interaction with signaling proteins. Alterations to lipids have been associated with important diseases, and, consequently, normalization of these alterations or regulatory interventions that control membrane lipid composition have therapeutic potential. This approach, termed membrane lipid therapy or membrane lipid replacement, has emerged as a novel technology platform for nutraceutical interventions and drug discovery. Several clinical trials and therapeutic products have validated this technology based on the understanding of membrane structure and function. The present review analyzes the molecular basis of this innovative approach, describing how membrane lipid composition and structure affects protein-lipid interactions, cell signaling, disease, and therapy (e.g., fatigue and cardiovascular, neurodegenerative, tumor, infectious diseases).
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A.K., Moharana,, Laxmi, V., and Prasad, L. "Computational Design for Human Angiotensin Converting Enzyme as a Target for Arjunolic Acid Causes Coronary Artery Disease." CARDIOMETRY, no. 24 (November 30, 2022): 345–52. http://dx.doi.org/10.18137/cardiometry.2022.24.345352.
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A leading cause of mortality around the globe is coronary artery disease (CAD). Major improvements in CAD therapy have been developed during the last ten years. According to the degree, kind, and clinical manifestation of CAD, the current treatments are either chemical treatments, surgical, or a combination of both. The bark of the Indian medicinal plant “Terminalia arjuna” has been used for decades as a heart stimulant. Several medicinal elements, including saponins and flavonoids, have been isolated from the bark. Terminalia arjuna has been the subject of numerous experimental and clinical research for its ability to treat cardiovascular diseases. Because protein-ligand interactions are important in structure-based treatment discovery, we used molecular docking to analyze Arjunolic acid (phytochemical found in T. arjuna) and examined their binding affinity against the cardiovascular target protein. The three-dimensional (3D) structure of the Human Angiotensin Converting Enzyme (Target Cardiovascular Protein) was obtained from Protein Data Bank and docked using the Autodock tool. As a result of our research, T. arjuna seems to be a good option for producing broad-spectrum medicines to treat cardiovascular disease.
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V., Laxmi,, Chakraborty, P., and Mishra, K. "In-Silico Docking Studies of Angiotensin Converting Enzyme Using Natural Inhibitor." CARDIOMETRY, no. 24 (November 30, 2022): 1046–52. http://dx.doi.org/10.18137/cardiometry.2022.24.10461052.
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Lowering blood pressure (BP) using antihypertensive medicines lowers the risk of target organ failure as well as the occurrence of cardiovascular disease. The most common modifiable risk factor for death and disability is hypertension, which is associated with strokes, increased coronary and systemic atherosclerosis, heart problems, and chronic kidney diseases (CKD). The majority of deaths and disabilities globally now result from cardiovascular diseases (CVDs), mainly in low- and middle-income nations. Numerous genetic, behavioral, and environmental risk factors all contribute to hypertension, a significant component in the advancement of CVD. Given the significance of protein-ligand interactions in structure-based therapy development, we molecularly docked nifedipine to the cardiovascular target protein to determine the drug’s binding affinity. The Angiotensin Converting Enzyme (Target hypertension Protein) three-dimensional (3D) structure was docked using the Autodock tool, which was retrieved from the Protein Data Bank (PDB). Our analysis indicates that nifedipine is an effective choice for treating hypertension and reducing the symptoms of angina (chest pain).
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Golpanian, Samuel, Ariel Wolf, Konstantinos E. Hatzistergos, and Joshua M. Hare. "Rebuilding the Damaged Heart: Mesenchymal Stem Cells, Cell-Based Therapy, and Engineered Heart Tissue." Physiological Reviews 96, no. 3 (July 2016): 1127–68. http://dx.doi.org/10.1152/physrev.00019.2015.
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Mesenchymal stem cells (MSCs) are broadly distributed cells that retain postnatal capacity for self-renewal and multilineage differentiation. MSCs evade immune detection, secrete an array of anti-inflammatory and anti-fibrotic mediators, and very importantly activate resident precursors. These properties form the basis for the strategy of clinical application of cell-based therapeutics for inflammatory and fibrotic conditions. In cardiovascular medicine, administration of autologous or allogeneic MSCs in patients with ischemic and nonischemic cardiomyopathy holds significant promise. Numerous preclinical studies of ischemic and nonischemic cardiomyopathy employing MSC-based therapy have demonstrated that the properties of reducing fibrosis, stimulating angiogenesis, and cardiomyogenesis have led to improvements in the structure and function of remodeled ventricles. Further attempts have been made to augment MSCs' effects through genetic modification and cell preconditioning. Progression of MSC therapy to early clinical trials has supported their role in improving cardiac structure and function, functional capacity, and patient quality of life. Emerging data have supported larger clinical trials that have been either completed or are currently underway. Mechanistically, MSC therapy is thought to benefit the heart by stimulating innate anti-fibrotic and regenerative responses. The mechanisms of action involve paracrine signaling, cell-cell interactions, and fusion with resident cells. Trans-differentiation of MSCs to bona fide cardiomyocytes and coronary vessels is also thought to occur, although at a nonphysiological level. Recently, MSC-based tissue engineering for cardiovascular disease has been examined with quite encouraging results. This review discusses MSCs from their basic biological characteristics to their role as a promising therapeutic strategy for clinical cardiovascular disease.
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Lau, Skadi, Manfred Gossen, and Andreas Lendlein. "Designing Cardiovascular Implants Taking in View the Endothelial Basement Membrane." International Journal of Molecular Sciences 22, no. 23 (December 4, 2021): 13120. http://dx.doi.org/10.3390/ijms222313120.
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Insufficient endothelialization of cardiovascular grafts is a major hurdle in vascular surgery and regenerative medicine, bearing a risk for early graft thrombosis. Neither of the numerous strategies pursued to solve these problems were conclusive. Endothelialization is regulated by the endothelial basement membrane (EBM), a highly specialized part of the vascular extracellular matrix. Thus, a detailed understanding of the structure–function interrelations of the EBM components is fundamental for designing biomimetic materials aiming to mimic EBM functions. In this review, a detailed description of the structure and functions of the EBM are provided, including the luminal and abluminal interactions with adjacent cell types, such as vascular smooth muscle cells. Moreover, in vivo as well as in vitro strategies to build or renew EBM are summarized and critically discussed. The spectrum of methods includes vessel decellularization and implant biofunctionalization strategies as well as tissue engineering-based approaches and bioprinting. Finally, the limitations of these methods are highlighted, and future directions are suggested to help improve future design strategies for EBM-inspired materials in the cardiovascular field.
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Bora, Şebnem, Vedat Evren, Sevcan Emek, and Ibrahim Çakırlar. "Agent-based modeling and simulation of blood vessels in the cardiovascular system." SIMULATION 95, no. 4 (June 9, 2017): 297–312. http://dx.doi.org/10.1177/0037549717712602.
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The purpose of this study is to develop a model to simulate the behavior of the human cardiovascular system for use in medical education. The proposed model ensures that the output of the system is accurately represented in both equilibrium conditions and imbalance conditions including in the presence of adaptive agents. In this study, field experts develop an agent-based blood vessel model, i.e., a submodel for the stated purpose. In the proposed blood vessel model, vessels are represented by agents whereas blood flow is represented by the interaction between agents. Adaptive behavior shown by vessels in terms of resistance to the blood flow is defined by the agents’ properties, which are used as the basis for calculating and graphically representing the physical parameters of blood flow, specifically blood pressure, blood flow velocity, and the resistance of the vessel. The adaptation of the vessel agents is supported by a case study, which demonstrates the adaptive behavior of the blood vessel agents through a negative feedback control mechanism. The blood vessel model proposed is flexible in nature such that it can be adapted to account for the behavior of the vessel sections in any vascular structure.
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Dixit, Vaibhav A., and Prasad V. Bharatam. "SAR and Computer-Aided Drug Design Approaches in the Discovery of Peroxisome Proliferator-Activated Receptor γ Activators: A Perspective." Journal of Computational Medicine 2013 (April 4, 2013): 1–38. http://dx.doi.org/10.1155/2013/406049.
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Activators of PPARγ, Troglitazone (TGZ), Rosiglitazone (RGZ), and Pioglitazone (PGZ) were introduced for treatment of Type 2 diabetes, but TGZ and RGZ have been withdrawn from the market along with other promising leads due cardiovascular side effects and hepatotoxicity. However, the continuously improving understanding of the structure/function of PPARγ and its interactions with potential ligands maintain the importance of PPARγ as an antidiabetic target. Extensive structure activity relationship (SAR) studies have thus been performed on a variety of structural scaffolds by various research groups. Computer-aided drug discovery (CADD) approaches have also played a vital role in the search and optimization of potential lead compounds. This paper focuses on these approaches adopted for the discovery of PPARγ ligands for the treatment of Type 2 diabetes. Key concepts employed during the discovery phase, classification based on agonistic character, applications of various QSAR, pharmacophore mapping, virtual screening, molecular docking, and molecular dynamics studies are highlighted. Molecular level analysis of the dynamic nature of ligand-receptor interaction is presented for the future design of ligands with better potency and safety profiles. Recently identified mechanism of inhibition of phosphorylation of PPARγ at SER273 by ligands is reviewed as a new strategy to identify novel drug candidates.
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James, Bryan D., Brian Caffo, Walter F. Stewart, David Yousem, Christos Davatzikos, and Brian S. Schwartz. "Genetic Risk Factors for Longitudinal Changes in Structural MRI in Former Organolead Workers." Journal of Aging Research 2011 (2011): 1–11. http://dx.doi.org/10.4061/2011/362189.
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This study examined associations between polymorphisms in three genes, apolipoprotein E (APOE), angiotensin converting enzyme (ACE), and vitamin D receptor (VDR), and longitudinal change in brain volumes and white matter lesions (WML) as well as effect modification by cardiovascular factors and tibia lead concentrations. Two MRIs, an average of 5 years apart, were obtained for 317 former organolead workers and 45 population-based controls. Both regions-of-interest and voxel-wise analyses were conducted.APOEε3/ε4andε4/ε4genotypes were associated with less decline in white matter volumes. There was some evidence of interaction between genetic polymorphisms and cardiovascular risk factors (ACEand high-density lipoprotein;VDRand diabetes) on brain volume decline. TheVDR FokIff genotype was associated with an increase in WML (no association forAPOEorACE). This study expands our understanding of how genetic precursors of dementia and cardiovascular diseases are related to changes in brain structure.
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van Bakel, Theodorus M. J., Christopher J. Arthurs, Foeke J. H. Nauta, Kim A. Eagle, Joost A. van Herwaarden, Frans L. Moll, Santi Trimarchi, Himanshu J. Patel, and C. Alberto Figueroa. "Cardiac remodelling following thoracic endovascular aortic repair for descending aortic aneurysms." European Journal of Cardio-Thoracic Surgery 55, no. 6 (December 6, 2018): 1061–70. http://dx.doi.org/10.1093/ejcts/ezy399.
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Abstract OBJECTIVES Current endografts for thoracic endovascular aortic repair (TEVAR) are much stiffer than the aorta and have been shown to induce acute stiffening. In this study, we aimed to estimate the impact of TEVAR on left ventricular (LV) stroke work (SW) and mass using a non-invasive image-based workflow. METHODS The University of Michigan database was searched for patients treated with TEVAR for descending aortic pathologies (2013–2016). Patients with available pre-TEVAR and post-TEVAR computed tomography angiography and echocardiography data were selected. LV SW was estimated via patient-specific fluid–structure interaction analyses. LV remodelling was quantified through morphological measurements using echocardiography and electrocardiographic-gated computed tomography angiography data. RESULTS Eight subjects were included in this study, the mean age of the patients was 68 (73, 25) years, and 6 patients were women. All patients were prescribed antihypertensive drugs following TEVAR. The fluid–structure interaction simulations computed a 26% increase in LV SW post-TEVAR [0.94 (0.89, 0.34) J to 1.18 (1.11, 0.65) J, P = 0.012]. Morphological measurements revealed an increase in the LV mass index post-TEVAR of +26% in echocardiography [72 (73, 17) g/m2 to 91 (87, 26) g/m2, P = 0.017] and +15% in computed tomography angiography [52 (46, 29) g/m2 to 60 (57, 22) g/m2, P = 0.043]. The post- to pre-TEVAR LV mass index ratio was positively correlated with the post- to pre-TEVAR ratios of SW and the mean blood pressure (ρ = 0.690, P = 0.058 and ρ = 0.786, P = 0.021, respectively). CONCLUSIONS TEVAR was associated with increased LV SW and mass during follow-up. Medical device manufacturers should develop more compliant devices to reduce the stiffness mismatch with the aorta. Additionally, intensive antihypertensive management is needed to control blood pressure post-TEVAR.