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1

Model Systems for Cardiovascular Regenerative Biology  

PubMed Central

There is an urgent clinical need to develop new therapeutic approaches to treat heart failure, but the biology of cardiovascular regeneration is complex. Model systems are required to advance our understanding of biological mechanisms of cardiac regeneration as well as to test therapeutic approaches to regenerate tissue and restore cardiac function following injury. An ideal model system should be inexpensive, easily manipulated, easily reproducible, physiologically representative of human disease, and ethically sound. In this review, we discuss computational, cell-based, tissue, and animal models that have been used to elucidate mechanisms of cardiovascular regenerative biology or to test proposed therapeutic methods to restore cardiac function following disease or injury. PMID:23545574

Garbern, Jessica C.; Mummery, Christine L.

2013-01-01

2

Computer model of cardiovascular control system responses to exercise  

NASA Technical Reports Server (NTRS)

Approaches of systems analysis and mathematical modeling together with computer simulation techniques are applied to the cardiovascular system in order to simulate dynamic responses of the system to a range of exercise work loads. A block diagram of the circulatory model is presented, taking into account arterial segments, venous segments, arterio-venous circulation branches, and the heart. A cardiovascular control system model is also discussed together with model test results.

Croston, R. C.; Rummel, J. A.; Kay, F. J.

1973-01-01

3

A cardiovascular model for blood pressure control systems  

Microsoft Academic Search

A cardiovascular model for blood pressure control system is developed in this paper. This model is used to simulate hypertensive patients in order to design control systems for regulation of blood pressure. The stability of the model is also investigated. The model can accurately represent human arterial blood pressure and therefore, the control system designed and simulated based on the

P. C. A. Ang; B. W. Ang; K. Y. Zhu

2009-01-01

4

Haemodynamic modeling of the cardiovascular system using mock circulation loops to test cardiovascular devices.  

PubMed

Comprehensive testing and evaluation of cardiovascular device function and performance is required prior to clinical implementation. Initial proof of concept investigations are conducted within in-vitro mock circulation loops, before proof of principle is demonstrated via in-vivo animal testing. To facilitate the rapid transition of cardiovascular devices through this development period, a testing apparatus was developed that closely models the natural human cardiovascular system haemodynamics. This mock circulation system accurately replicates cardiac function, coupled to systemic and pulmonary circulations. The physiological response produced by a number of clinical cardiovascular conditions can be actively controlled by variable parameters such as vascular resistance, arterial/venous compliance, ventricle contractility, heart rate, and heart /vascular volumes, while anatomical variations such as valve regurgitation and septal defects can be included. Auto-regulation of these parameters was attempted to reproduce the Frank-Starling mechanism, baroreceptor reflex, skeletal muscle pump, and postural changes. Steady state validation of loop performance was achieved by replicating the progression of a patient's clinical haemodynamics from heart failure, through VAD support, to heart transplantation. The system has been used to evaluate pulsatile and non-pulsatile ventricular assist devices, counter pulsation devices, non-invasive cardiac output monitors and cardiovascular stents. The interaction of these devices with the cardiovascular system was also investigated with regards to physiological control strategies and cannula placement. The system is a valuable tool for the accelerated progression of cardiovascular device development. PMID:22255291

Timms, Daniel L; Gregory, Shaun D; Stevens, Michael C; Fraser, John F

2011-01-01

5

A novel approach to modeling and diagnosing the cardiovascular system  

SciTech Connect

A novel approach to modeling and diagnosing the cardiovascular system is introduced. A model exhibits a subset of the dynamics of the cardiovascular behavior of an individual by using a recurrent artificial neural network. Potentially, a model will be incorporated into a cardiovascular diagnostic system. This approach is unique in that each cardiovascular model is developed from physiological measurements of an individual. Any differences between the modeled variables and the variables of an individual at a given time are used for diagnosis. This approach also exploits sensor fusion to optimize the utilization of biomedical sensors. The advantage of sensor fusion has been demonstrated in applications including control and diagnostics of mechanical and chemical processes.

Keller, P.E.; Kangas, L.J.; Hashem, S.; Kouzes, R.T. [Pacific Northwest Lab., Richland, WA (United States); Allen, P.A. [Life Link, Richland, WA (United States)

1995-07-01

6

Cardiovascular system  

MedlinePLUS Videos and Cool Tools

The cardiovascular system is composed of the heart and the network of arteries, veins, and capillaries that transport blood throughout the ... carries waste products from the tissues to the systems of the body through which they are eliminated. ...

7

A Computer Model of the Cardiovascular System for Effective Learning.  

ERIC Educational Resources Information Center

Presents a model of the cardiovascular system which solves a set of interacting, possibly nonlinear, differential equations. Figures present a schematic diagram of the model and printouts that simulate normal conditions, exercise, hemorrhage, reduced contractility. The nine interacting equations used to describe the system are described in the…

Rothe, Carl F.

1980-01-01

8

A Computer Model of the Cardiovascular System for Effective Learning.  

ERIC Educational Resources Information Center

Described is a physiological model which solves a set of interacting, possibly nonlinear, differential equations through numerical integration on a digital computer. Sample printouts are supplied and explained for effects on the components of a cardiovascular system when exercise, hemorrhage, and cardiac failure occur. (CS)

Rothe, Carl F.

1979-01-01

9

Modeling, Estimation and Control of Cardiovascular Systems with A Left Ventricular Assist Device  

E-print Network

to approximate the response of human cardiovascular circulatory system. This system model has one critical time as test environments for human cardiovascular circulatory systems with a left ventric- ular assist device patient are restored back to the normal physiologic range. Keywords: Cardiovascular circulatory system

Wu, Yi

10

Mathematical modelling of flow distribution in the human cardiovascular system  

NASA Technical Reports Server (NTRS)

The paper presents a detailed model of the entire human cardiovascular system which aims to study the changes in flow distribution caused by external stimuli, changes in internal parameters, or other factors. The arterial-venous network is represented by 325 interconnected elastic segments. The mathematical description of each segment is based on equations of hydrodynamics and those of stress/strain relationships in elastic materials. Appropriate input functions provide for the pumping of blood by the heart through the system. The analysis employs the finite-element technique which can accommodate any prescribed boundary conditions. Values of model parameters are from available data on physical and rheological properties of blood and blood vessels. As a representative example, simulation results on changes in flow distribution with changes in the elastic properties of blood vessels are discussed. They indicate that the errors in the calculated overall flow rates are not significant even in the extreme case of arteries and veins behaving as rigid tubes.

Sud, V. K.; Srinivasan, R. S.; Charles, J. B.; Bungo, M. W.

1992-01-01

11

Reintrepreting the cardiovascular system as a mechanical model  

NASA Astrophysics Data System (ADS)

The simulation of the different physiological systems is very useful as a pedagogical tool, allowing a better understanding of the mechanisms and the functions of the processes. The observation of the physiological phenomena through mechanical simulators represents a great asset. Furthermore, the development of these simulators allows reinterpreting physiological systems, with the advantage of using the same transducers and sensors that are commonly used in diagnostic and therapeutic cardiovascular procedures for the monitoring of system' parameters. The cardiovascular system is one of the most important systems of the human body and has been the target of several biomedical studies. The present work describes a mechanical simulation of the cardiovascular system, in particularly, the systemic circulation, which can be described in terms of its hemodynamic variables. From the mechanical process and parameters, physiological system's behavior was reproduced, as accurately as possible.

Lemos, Diogo; Machado, José; Minas, Graça; Soares, Filomena; Barros, Carla; Leão, Celina Pinto

2013-10-01

12

[Study of modeling and simulation of the multi-branch cardiovascular system].  

PubMed

By the Power Band Graph(PBG) method, this paper presents a computer simulation model of the multi-branch cardiovascular circulation system, which describes the blood fluid dynamic law in the cardiovacular system by the state equation. The model gives a minute description on physiological characters of cardiovascular circulation system (CVS). An integrate computer model on CVS has been established. The model can simulate physiological characters of cardiovascular circulation system and get the simulation data and the curves of CVS hemodynamics variables. The model can be used widely in the field of physiological system simulation study, medical study, and computer-aided instruction. PMID:12557777

Feng, Y; Hang, X; Tian, S

2000-06-01

13

Mathematical modeling of human cardiovascular system for simulation of orthostatic response  

NASA Technical Reports Server (NTRS)

This paper deals with the short-term response of the human cardiovascular system to orthostatic stresses in the context of developing a mathematical model of the overall system. It discusses the physiological issues involved and how these issues have been handled in published cardiovascular models for simulation of orthostatic response. Most of the models are stimulus specific with no demonstrated capability for simulating the responses to orthostatic stimuli of different types. A comprehensive model incorporating all known phenomena related to cardiovascular regulation would greatly help to interpret the various orthostatic responses of the system in a consistent manner and to understand the interactions among its elements. This paper provides a framework for future efforts in mathematical modeling of the entire cardiovascular system.

Melchior, F. M.; Srinivasan, R. S.; Charles, J. B.

1992-01-01

14

Space physiology IV: mathematical modeling of the cardiovascular system in space exploration.  

PubMed

Mathematical modeling represents an important tool for analyzing cardiovascular function during spaceflight. This review describes how modeling of the cardiovascular system can contribute to space life science research and illustrates this process via modeling efforts to study postflight orthostatic intolerance (POI), a key issue for spaceflight. Examining this application also provides a context for considering broader applications of modeling techniques to the challenges of bioastronautics. POI, which affects a large fraction of astronauts in stand tests upon return to Earth, presents as dizziness, fainting and other symptoms, which can diminish crew performance and cause safety hazards. POI on the Moon or Mars could be more critical. In the field of bioastronautics, POI has been the dominant application of cardiovascular modeling for more than a decade, and a number of mechanisms for POI have been investigated. Modeling approaches include computational models with a range of incorporated factors and hemodynamic sophistication, and also physical models tested in parabolic and orbital flight. Mathematical methods such as parameter sensitivity analysis can help identify key system mechanisms. In the case of POI, this could lead to more effective countermeasures. Validation is a persistent issue in modeling efforts, and key considerations and needs for experimental data to synergistically improve understanding of cardiovascular responses are outlined. Future directions in cardiovascular modeling include subject-specific assessment of system status, as well as research on integrated physiological responses, leading, for instance, to assessment of subject-specific susceptibility to POI or effects of cardiovascular alterations on muscular, vision and cognitive function. PMID:23539439

Keith Sharp, M; Batzel, Jerry Joseph; Montani, Jean-Pierre

2013-08-01

15

A bond graph model of the cardiovascular system Le Rolle Virginie 1 2  

E-print Network

. In this paper, a new model of the CVS, representing the ventricles, the circulatory system and the regulation activity, the circulatory system and evidently the autonomic baroreflex loop includingi) ii) iii) affereA bond graph model of the cardiovascular system Le Rolle Virginie 1 2 , Hernandez Alfredo I. 1

Boyer, Edmond

16

from SIAM News, Volume 34, Number 6 Modeling the Cardiovascular System--  

E-print Network

, and are certainly not applicable to the circulatory system as a whole1 from SIAM News, Volume 34, Number 6 Modeling the Cardiovascular System-- A Mathematical Adventure system, and the difficulty of coupling the different mathematical models appropriate for the different

Canic, Suncica

17

A Mathematical Model for the First-Pass Dynamics of Antibiotics Acting on the Cardiovascular System  

E-print Network

delivered to the lungs on a first circulatory pass. Key words: Compartmental model, circulatory system, drugA Mathematical Model for the First-Pass Dynamics of Antibiotics Acting on the Cardiovascular System compounds to the lungs and heart. We use a compartmental mass balance approach to develop a system

18

A forward model-based analysis of cardiovascular system identification methods  

E-print Network

Cardiovascular system identification is a potentially powerful approach for intelligent patient monitoring of cardiovascular function. Rather than merely recording hemodynamic signals, the signals are mathematically analyzed ...

Mukkamala, Ramakrishna, 1971-

2000-01-01

19

A cardiovascular system model for lower-body negative pressure response  

NASA Technical Reports Server (NTRS)

Mathematical models used to study complex physiological control systems are discussed. Efforts were made to modify a model of the cardiovascular system for use in studying lower body negative pressure. A computer program was written which allows orderly, straightforward expansion to include exercise, metabolism (thermal stress), respiration, and other body functions.

Mitchell, B. A., Jr.; Giese, R. P.

1971-01-01

20

Mathematical modelling of the human cardiovascular system in the presence of stenosis  

NASA Technical Reports Server (NTRS)

This paper reports a theoretical study on the distribution of blood flow in the human cardiovascular system when one or more blood vessels are affected by stenosis. The analysis employs a mathematical model of the entire system based on the finite element method. The arterial-venous network is represented by a large number of interconnected segments in the model. Values for the model parameters are based upon the published data on the physiological and rheological properties of blood. Computational results show how blood flow through various parts of the cardiovascular system is affected by stenosis in different blood vessels. No significant changes in the flow parameters of the cardiovascular system were found to occur when the reduction in the lumen diameter of the stenosed vessels was less than 65%.

Sud, V. K.; Srinivasan, R. S.; Charles, J. B.; Bungo, M. W.

1993-01-01

21

Study report on guidelines and test procedures for investigating stability of nonlinear cardiovascular control system models  

NASA Technical Reports Server (NTRS)

A general study of the stability of nonlinear as compared to linear control systems is presented. The analysis is general and, therefore, applies to other types of nonlinear biological control systems as well as the cardiovascular control system models. Both inherent and numerical stability are discussed for corresponding analytical and graphic methods and numerical methods.

Fitzjerrell, D. G.

1974-01-01

22

Adaptive life simulator: A novel approach to modeling the cardiovascular system  

SciTech Connect

In this paper, an adaptive life simulator (ALS) is introduced. The ALS models a subset of the dynamics of the cardiovascular behavior of an individual by using a recurrent artificial neural network. These models are developed for use in applications that require simulations of cardiovascular systems, such as medical mannequins, and in medical diagnostic systems. This approach is unique in that each cardiovascular model is developed from physiological measurements of an individual. Any differences between the modeled variables and the actual variables of an individual can subsequently be used for diagnosis. This approach also exploits sensor fusion applied to biomedical sensors. Sensor fusion optimizes the utilization of the sensors. The advantage of sensor fusion has been demonstrated in applications including control and diagnostics of mechanical and chemical processes.

Kangas, L.J.; Keller, P.E.; Hashem, S. [and others

1995-06-01

23

Review of Zero-D and 1-D Models of Blood Flow in the Cardiovascular System  

PubMed Central

Background Zero-dimensional (lumped parameter) and one dimensional models, based on simplified representations of the components of the cardiovascular system, can contribute strongly to our understanding of circulatory physiology. Zero-D models provide a concise way to evaluate the haemodynamic interactions among the cardiovascular organs, whilst one-D (distributed parameter) models add the facility to represent efficiently the effects of pulse wave transmission in the arterial network at greatly reduced computational expense compared to higher dimensional computational fluid dynamics studies. There is extensive literature on both types of models. Method and Results The purpose of this review article is to summarise published 0D and 1D models of the cardiovascular system, to explore their limitations and range of application, and to provide an indication of the physiological phenomena that can be included in these representations. The review on 0D models collects together in one place a description of the range of models that have been used to describe the various characteristics of cardiovascular response, together with the factors that influence it. Such models generally feature the major components of the system, such as the heart, the heart valves and the vasculature. The models are categorised in terms of the features of the system that they are able to represent, their complexity and range of application: representations of effects including pressure-dependent vessel properties, interaction between the heart chambers, neuro-regulation and auto-regulation are explored. The examination on 1D models covers various methods for the assembly, discretisation and solution of the governing equations, in conjunction with a report of the definition and treatment of boundary conditions. Increasingly, 0D and 1D models are used in multi-scale models, in which their primary role is to provide boundary conditions for sophisticate, and often patient-specific, 2D and 3D models, and this application is also addressed. As an example of 0D cardiovascular modelling, a small selection of simple models have been represented in the CellML mark-up language and uploaded to the CellML model repository http://models.cellml.org/. They are freely available to the research and education communities. Conclusion Each published cardiovascular model has merit for particular applications. This review categorises 0D and 1D models, highlights their advantages and disadvantages, and thus provides guidance on the selection of models to assist various cardiovascular modelling studies. It also identifies directions for further development, as well as current challenges in the wider use of these models including service to represent boundary conditions for local 3D models and translation to clinical application. PMID:21521508

2011-01-01

24

Silicon Baroreceptors: Modeling Cardiovascular  

E-print Network

Silicon Baroreceptors: Modeling Cardiovascular Pressure Transduction in Analog VLSI John Lazzaro of the baroreceptors in the carotid vessel. Inspired by re- cent work in silicon models of the cochlea [3

Lazzaro, John

25

Flow and pressure regulation in the cardiovascular system. [engineering systems model  

NASA Technical Reports Server (NTRS)

Principles and descriptive fragments which may contribute to a model of the regulating chains in the cardiovascular system are presented. Attention is given to the strain sensitivity of blood vessels, the law of the autonomy of the heart beat oscillator, the law of the encapsulation of body fluids, the law of the conservation of protein, the law of minimum 'arterial' pressure, the design of the 'mammalian' kidney, questions of homeokinetic organization, and the development of self-regulatory chains. Details concerning the development program for the heart muscle are considered along with the speed of response of the breathing rate and the significance of the pulmonary vascular pressure-flow characteristics.

Iberall, A.

1974-01-01

26

Confronting a Cardiovascular System Model with Heart Rate and Blood Pressure Data  

E-print Network

to a range of disorders including congestive heart failure, stroke, myocardial infarction and kidney failureConfronting a Cardiovascular System Model with Heart Rate and Blood Pressure Data PE McSharry1 fluctuations in the heart rate, blood pressure and rate of respiration. Its time evolution is governed

McSharry, Patrick E.

27

Confronting a Cardiovascular System Model with Heart Rate and Blood Pressure Data  

E-print Network

to a range of disorders including congestive heart failure, stroke, myocardial infarction and kidney failureConfronting a Cardiovascular System Model with Heart Rate and Blood Pressure Data PE McSharry 1 fluctuations in the heart rate, blood pressure and rate of respiration. Its time evolution is governed

McSharry, Patrick E.

28

Confronting a cardiovascular system model with heart rate and blood pressure data  

Microsoft Academic Search

The cardiovascular system may be investigated by observing fluctuations in the heart rate, blood pressure and rate of respiration. Its time evolution is governed by the baroreflex control mechanism, where the sympathetic and vagal nerves compete to increase and decrease the heart rate respectively. A nonlinear delay-differential equation model is constructed to describe this control mechanism and to explore the

P. E. McSharry; M. J. McGuinness; A. C. Fowler

2005-01-01

29

Computational Models of the Cardiovascular System and Its Response to Microgravity  

NASA Technical Reports Server (NTRS)

Computational models of the cardiovascular system are powerful adjuncts to ground-based and in-flight experiments. We will provide NSBRI with a model capable of simulating the short-term effects of gravity on cardiovascular function. The model from this project will: (1) provide a rational framework which quantitatively defines interactions among complex cardiovascular parameters and which supports the critical interpretation of experimental results and testing of hypotheses. (2) permit predictions of the impact of specific countermeasures in the context of various hypothetical cardiovascular abnormalities induced by microgravity. Major progress has been made during the first 18 months of the program: (1) We have developed an operational first-order computer model capable of simulating the cardiovascular response to orthostatic stress. The model consists of a lumped parameter hemodynamic model and a complete reflex control system. The latter includes cardiopulmonary and carotid sinus reflex limbs and interactions between the two. (2) We have modeled the physiologic stress of tilt table experiments and lower body negative pressure procedures (LBNP). We have verified our model's predictions by comparing them with experimental findings from the literature. (3) We have established collaborative efforts with leading investigators interested in experimental studies of orthostatic intolerance, cardiovascular control, and physiologic responses to space flight. (4) We have established a standardized method of transferring data to our laboratory from the ongoing NSBRI bedrest studies. We use this data to estimate input parameters to our model and compare our model predictions to actual data to further verify our model. (5) We are in the process of systematically simulating current hypotheses concerning the mechanism underlying orthostatic intolerance by matching our simulations to stand test data from astronauts pre- and post-flight. (6) We are in the process of developing a JAVA version of the simulator which will be distributed amongst the cardiovascular team members. Future work on this project involves modifications of the model to represent a rodent (rat) model, further evaluation of the bedrest astronaut and animal data, and systematic investigation of specific countermeasures.

Kamm, Roger D.

1999-01-01

30

Modeling the cardiovascular system using a nonlinear additive autoregressive model with exogenous input  

NASA Astrophysics Data System (ADS)

The parameters of heart rate variability and blood pressure variability have proved to be useful analytical tools in cardiovascular physics and medicine. Model-based analysis of these variabilities additionally leads to new prognostic information about mechanisms behind regulations in the cardiovascular system. In this paper, we analyze the complex interaction between heart rate, systolic blood pressure, and respiration by nonparametric fitted nonlinear additive autoregressive models with external inputs. Therefore, we consider measurements of healthy persons and patients suffering from obstructive sleep apnea syndrome (OSAS), with and without hypertension. It is shown that the proposed nonlinear models are capable of describing short-term fluctuations in heart rate as well as systolic blood pressure significantly better than similar linear ones, which confirms the assumption of nonlinear controlled heart rate and blood pressure. Furthermore, the comparison of the nonlinear and linear approaches reveals that the heart rate and blood pressure variability in healthy subjects is caused by a higher level of noise as well as nonlinearity than in patients suffering from OSAS. The residue analysis points at a further source of heart rate and blood pressure variability in healthy subjects, in addition to heart rate, systolic blood pressure, and respiration. Comparison of the nonlinear models within and among the different groups of subjects suggests the ability to discriminate the cohorts that could lead to a stratification of hypertension risk in OSAS patients.

Riedl, M.; Suhrbier, A.; Malberg, H.; Penzel, T.; Bretthauer, G.; Kurths, J.; Wessel, N.

2008-07-01

31

Interactive Cardiovascular System Map  

NSDL National Science Digital Library

The cardiovascular portion of the InnerBody website is a road map to the human cardiovascular system. It displays all of the main veins and arteries of the human body allowing the user to click on various parts of body and dozens of links to the many different systems appear. Users can hover over the links to discover what each part is named, or click on the link to be brought to a thorough definition and description of the selected system. Users may also �zoom in� on certain parts to view more detail. In addition to the interactive �map,� InnerBody also has images and descriptions about common issues that arise within the cardiovascular system.

32

Fluctuations in a coupled-oscillator model of the cardiovascular system  

NASA Astrophysics Data System (ADS)

We present a model of the cardiovascular system (CVS) based on a system of coupled oscillators. Using this approach we can describe several complex physiological phenomena that can have a range of applications. For instance, heart rate variability (HRV), can have a new deterministic explanation. The intrinsic dynamics of the HRV is controlled by deterministic couplings between the physiological oscillators in our model and without the need to introduce external noise as is commonly done. This new result provides potential applications not only for physiological systems but also for the design of very precise electronic generators where the frequency stability is crucial. Another important phenomenon is that of oscillation death. We show that in our CVS model the mechanism leading to the quenching of the oscillations can be controlled, not only by the coupling parameter, but by a more general scheme. In fact, we propose that a change in the relative current state of the cardiovascular oscillators can lead to a cease of the oscillations without actually changing the strength of the coupling among them. We performed real experiments using electronic oscillators and show them to match the theoretical and numerical predictions. We discuss the relevance of the studied phenomena to real cardiovascular systems regimes, including the explanation of certain pathologies, and the possible applications in medical practice.

González, Jorge A.; Suárez-Vargas, Jose J.; Stefanovska, Aneta; McClintock, Peter V. E.

2007-06-01

33

A Delay Recruitment Model of the Cardiovascular Control System  

E-print Network

system, and use it to explore blood pressure and heart rate variability under short-term baroreflex of baroreflex health, using natural variations in heart rate and blood pressure data, requires a deep. Understanding the way that natural vari- ability in blood pressure and heart rate depend on the health

McGuinness, Mark

34

Receding Horizon Controller for the Baroreceptor Loop in a Model for the Cardiovascular System  

Microsoft Academic Search

In this article, we discuss the design and implementation of a receding horizon control (RHC) which will be used to represent\\u000a the control for the baroreceptor loop in the human cardiovascular system (CVS). This control will be applied to a model of\\u000a the CVS developed in a previous work by Kappel and Peer. In that earlier work, a linear quadratic

Mark Mutsaers; Mostafa Bachar; Jerry Batzel; Franz Kappel; Stefan Volkwein

2008-01-01

35

A Closed-Loop Lumped Parameter Computational Model for Human Cardiovascular System  

NASA Astrophysics Data System (ADS)

For purpose of a better understanding of the behavior of the global hemodynamic interactions, a closed-loop lumped parameter computational model was developed for the human cardiovascular system with a detailed compartmental description of the heart and the main vascular circulations. Construction of the model was implemented based on a phenomenological characterization of hemodynamics using an electrical analog method and solution of the governing differential equations of the model was carried out by use of a fourth-order Runge-Kutta method. Most of the hemodynamic parameters predicted by the present model were either consonant with the clinical measurements or within reasonable physiological ranges. Furthermore, the present model was applied to predict the clinical cardiac hemodynamic characteristics observed in patients with heart abnormalities. Reasonable agreements between predictions and measurements indicate that the present computational model can serve as a useful assistant tool for computer-aided diagnosis and surgical treatment, as well as posttreatment prediction.

Liang, Fuyou; Liu, Hao

36

A multiformalism and multiresolution modelling environment: application to the cardiovascular system and its regulation  

PubMed Central

The role of modelling and simulation on the systemic analysis of living systems is now clearly established. Emerging disciplines, such as Systems Biology, and world-wide research actions, such as the Physiome project or the Virtual Physiological Human, are based on an intensive use of modelling and simulation methodologies and tools. One of the key aspects in this context is to perform an efficient integration of various models representing different biological or physiological functions, at different resolutions, spanning through different scales. This paper presents a multi-formalism modelling and simulation environment (M2SL) that has been conceived to ease model integration. A given model is represented as a set of coupled and atomic model components that may be based on different mathematical formalisms with heterogeneous structural and dynamical properties. A co-simulation approach is used to solve these hybrid systems. The pioneering model of the overall regulation of the cardiovascular system, proposed by Guyton, Coleman & Granger in 1972 has been implemented under M2SL and a pulsatile ventricular model, based on a time-varying elastance has been integrated, in a multi-resolution approach. Simulations reproducing physiological conditions and using different coupling methods show the benefits of the proposed environment. PMID:19884187

Hernández, Alfredo I.; Le Rolle, Virginie; Defontaine, Antoine; Carrault, Guy

2009-01-01

37

Optimization in Cardiovascular Modeling  

NASA Astrophysics Data System (ADS)

Fluid mechanics plays a key role in the development, progression, and treatment of cardiovascular disease. Advances in imaging methods and patient-specific modeling now reveal increasingly detailed information about blood flow patterns in health and disease. Building on these tools, there is now an opportunity to couple blood flow simulation with optimization algorithms to improve the design of surgeries and devices, incorporating more information about the flow physics in the design process to augment current medical knowledge. In doing so, a major challenge is the need for efficient optimization tools that are appropriate for unsteady fluid mechanics problems, particularly for the optimization of complex patient-specific models in the presence of uncertainty. This article reviews the state of the art in optimization tools for virtual surgery, device design, and model parameter identification in cardiovascular flow and mechanobiology applications. In particular, it reviews trade-offs between traditional gradient-based methods and derivative-free approaches, as well as the need to incorporate uncertainties. Key future challenges are outlined, which extend to the incorporation of biological response and the customization of surgeries and devices for individual patients.

Marsden, Alison L.

2014-01-01

38

Modeling high-order synchronization epochs and transitions in the cardiovascular system  

NASA Astrophysics Data System (ADS)

We study a system consisting of two coupled phase oscillators in the presence of noise. This system is used as a model for the cardiorespiratory interaction in wakefulness and anaesthesia. We show that longrange correlated noise produces transitions between epochs with different n:m synchronisation ratios, as observed in the cardiovascular system. Also, we see that, the smaller the noise (specially the one acting on the slower oscillator), the bigger the synchronisation time, exactly as happens in anaesthesia compared with wakefulness. The dependence of the synchronisation time on the couplings, in the presence of noise, is studied; such dependence is softened by low-frequency noise. We show that the coupling from the slow oscillator to the fast one (respiration to heart) plays a more important role in synchronisation. Finally, we see that the isolines with same synchronisation time seem to be a linear combination of the two couplings.

García-Álvarez, David; Bahraminasab, Alireza; Stefanovska, Aneta; McClintock, Peter V. E.

2007-12-01

39

Effects of nicotine on cardiovascular remodeling in a mouse model of systemic hypertension.  

PubMed

Usage of nicotine-only formulations, such as transdermal patches, nicotine gum, or electronic nicotine delivery systems is increasing, as they are perceived as healthier alternatives to traditional cigarettes. Unfortunately, there is little data available on the effect of isolated nicotine on myocardial and aortic remodeling, especially in the setting of cardiovascular disease risk factors, such as hypertension. We hypothesized that nicotine would exacerbate cardiovascular remodeling induced by angiotensin-II (Ang II) treatment. Subcutaneous osmotic minipumps were implanted to administer Ang II, Nic, nicotine plus Ang II or saline to C57Bl/6 mice for 4 weeks. Heart weights were increased by all treatments, with control < nicotine < Ang II < nicotine + Ang II. Activity levels of matrix metalloproteinase-2 mirrored these changes and demonstrated clear additivity between nicotine and Ang II. Histopathological analysis of aortas revealed that mice receiving combined nicotine and Ang II treatment induced significant hypertrophy compared to all other groups. This study reveals possible cardiotoxic interactions between nicotine and a common model of systemic hypertension. Safety testing of novel nicotine delivery devices should consider that hypertension is a common impetus to begin smoking cessation therapy, and potential interactions should be more thoroughly studied. PMID:23959951

Colombo, E Sage; Davis, Joshua; Makvandi, Mehran; Aragon, Mario; Lucas, Selita N; Paffett, Michael L; Campen, Matthew J

2013-12-01

40

Receding horizon controller for the baroreceptor loop in a model for the cardiovascular system.  

PubMed

In this article, we discuss the design and implementation of a receding horizon control (RHC) which will be used to represent the control for the baroreceptor loop in the human cardiovascular system (CVS). This control will be applied to a model of the CVS developed in a previous work by Kappel and Peer. In that earlier work, a linear quadratic control strategy (LQR) was implemented to represent this baroreflex control which was designed to stabilize the system under an ergometric workload. The RHC approach will be examined as an alternate to the LQR implementation. The control parameters in the cost functional of the RHC will be estimated using the same experimental data as was used in the LQR study. The results of the RHQ implementation will be compared with the LQR implementation. PMID:18058021

Mutsaers, Mark; Bachar, Mostafa; Batzel, Jerry; Kappel, Franz; Volkwein, Stefan

2008-03-01

41

A computational physiology approach to personalized treatment models: the beneficial effects of slow breathing on the human cardiovascular system.  

PubMed

Heart rate variability biofeedback intervention involves slow breathing at a rate of ?6 breaths/min (resonance breathing) to maximize respiratory and baroreflex effects on heart period oscillations. This intervention has wide-ranging clinical benefits and is gaining empirical support as an adjunct therapy for biobehavioral disorders, including asthma and depression. Yet, little is known about the system-level cardiovascular changes that occur during resonance breathing or the extent to which individuals differ in cardiovascular benefit. This study used a computational physiology approach to dynamically model the human cardiovascular system at rest and during resonance breathing. Noninvasive measurements of heart period, beat-to-beat systolic and diastolic blood pressure, and respiration period were obtained from 24 healthy young men and women. A model with respiration as input was parameterized to better understand how the cardiovascular processes that control variability in heart period and blood pressure change from rest to resonance breathing. The cost function used in model calibration corresponded to the difference between the experimental data and model outputs. A good match was observed between the data and model outputs (heart period, blood pressure, and corresponding power spectral densities). Significant improvements in several modeled cardiovascular functions (e.g., blood flow to internal organs, sensitivity of the sympathetic component of the baroreflex, ventricular elastance) were observed during resonance breathing. Individual differences in the magnitude and nature of these dynamic responses suggest that computational physiology may be clinically useful for tailoring heart rate variability biofeedback interventions for the needs of individual patients. PMID:25063789

Fonoberova, Maria; Mezi?, Igor; Buckman, Jennifer F; Fonoberov, Vladimir A; Mezi?, Adriana; Vaschillo, Evgeny G; Mun, Eun-Young; Vaschillo, Bronya; Bates, Marsha E

2014-10-01

42

An Integrated Model of the Cardiovascular and Central Nervous Systems for Analysis of Microgravity Induced Fluid Redistribution  

NASA Technical Reports Server (NTRS)

A recognized side effect of prolonged microgravity exposure is visual impairment and intracranial pressure (VIIP) syndrome. The medical understanding of this phenomenon is at present preliminary, although it is hypothesized that the headward shift of bodily fluids in microgravity may be a contributor. Computational models can be used to provide insight into the origins of VIIP. In order to further investigate this phenomenon, NASAs Digital Astronaut Project (DAP) is developing an integrated computational model of the human body which is divided into the eye, the cerebrovascular system, and the cardiovascular system. This presentation will focus on the development and testing of the computational model of an integrated model of the cardiovascular system (CVS) and central nervous system (CNS) that simulates the behavior of pressures, volumes, and flows within these two physiological systems.

Price, R.; Gady, S.; Heinemann, K.; Nelson, E. S.; Mulugeta, L.; Ethier, C. R.; Samuels, B. C.; Feola, A.; Vera, J.; Myers, J. G.

2015-01-01

43

Modeling of short-term mechanism of arterial pressure control in the cardiovascular system: object-oriented and acausal approach.  

PubMed

This letter introduces an alternative approach to modeling the cardiovascular system with a short-term control mechanism published in Computers in Biology and Medicine, Vol. 47 (2014), pp. 104-112. We recommend using abstract components on a distinct physical level, separating the model into hydraulic components, subsystems of the cardiovascular system and individual subsystems of the control mechanism and scenario. We recommend utilizing an acausal modeling feature of Modelica language, which allows model variables to be expressed declaratively. Furthermore, the Modelica tool identifies which are the dependent and independent variables upon compilation. An example of our approach is introduced on several elementary components representing the hydraulic resistance to fluid flow and the elastic response of the vessel, among others. The introduced model implementation can be more reusable and understandable for the general scientific community. PMID:25240104

Kulhánek, Tomáš; Kofránek, Ji?í; Mateják, Marek

2014-11-01

44

MODELING BLOOD FLOW IN THE CARDIOVASCULAR  

E-print Network

to be produced and consumed at the ends of a transport system whereas idea of a circulatory blood system of the circulatory cardiovasclar system § Harvey discovered the circulation of blood 46 year before the discoveryMODELING BLOOD FLOW IN THE CARDIOVASCULAR SYSTEM MA325 ­ Spring 2013 Department of Mathematics

Olufsen, Mette Sofie

45

Mathematical multi-scale model of the cardiovascular system including mitral valve dynamics. Application to ischemic mitral insufficiency  

PubMed Central

Background Valve dysfunction is a common cardiovascular pathology. Despite significant clinical research, there is little formal study of how valve dysfunction affects overall circulatory dynamics. Validated models would offer the ability to better understand these dynamics and thus optimize diagnosis, as well as surgical and other interventions. Methods A cardiovascular and circulatory system (CVS) model has already been validated in silico, and in several animal model studies. It accounts for valve dynamics using Heaviside functions to simulate a physiologically accurate "open on pressure, close on flow" law. However, it does not consider real-time valve opening dynamics and therefore does not fully capture valve dysfunction, particularly where the dysfunction involves partial closure. This research describes an updated version of this previous closed-loop CVS model that includes the progressive opening of the mitral valve, and is defined over the full cardiac cycle. Results Simulations of the cardiovascular system with healthy mitral valve are performed, and, the global hemodynamic behaviour is studied compared with previously validated results. The error between resulting pressure-volume (PV) loops of already validated CVS model and the new CVS model that includes the progressive opening of the mitral valve is assessed and remains within typical measurement error and variability. Simulations of ischemic mitral insufficiency are also performed. Pressure-Volume loops, transmitral flow evolution and mitral valve aperture area evolution follow reported measurements in shape, amplitude and trends. Conclusions The resulting cardiovascular system model including mitral valve dynamics provides a foundation for clinical validation and the study of valvular dysfunction in vivo. The overall models and results could readily be generalised to other cardiac valves. PMID:21942971

2011-01-01

46

MODELING BLOOD FLOW IN THE CARDIOVASCULAR  

E-print Network

was thought to be produced and consumed at the ends of a transport system whereas idea of a circulatory blood the discovery of the circulatory cardiovasclar system § Harvey discovered the circulation of blood 46 yearMODELING BLOOD FLOW IN THE CARDIOVASCULAR SYSTEM MA432 ­ Spring 2013 Department of Mathematics

Olufsen, Mette Sofie

47

Cardiovascular Biology of the Incretin System  

PubMed Central

Glucagon-like peptide-1 (GLP-1) is an incretin hormone that enhances glucose-stimulated insulin secretion and exerts direct and indirect actions on the cardiovascular system. GLP-1 and its related incretin hormone, glucose-dependent insulinotropic polypeptide (GIP), are rapidly inactivated by the enzyme dipeptidyl peptidase 4 (DPP-4), a key determinant of incretin bioactivity. Two classes of medications that enhance incretin action, GLP-1R agonists and DPP-4 inhibitors, are used for the treatment of type 2 diabetes mellitus (T2DM). We review herein the cardiovascular biology of GLP-1R agonists and DPP-4 inhibitors, including direct and indirect effects on cardiomyocytes, blood vessels, adipocytes, the control of blood pressure and postprandial lipoprotein secretion. Both GLP-1R activation and DPP-4 inhibition exert multiple cardioprotective actions in preclinical models of cardiovascular dysfunction, and short term studies in human subjects appear to demonstrate modest yet beneficial actions on cardiac function in subjects with ischemic heart disease. Incretin-based agents control body weight, improve glycemic control with a low risk of hypoglycemia, decrease blood pressure, inhibit the secretion of intestinal chylomicrons, and reduce inflammation in preclinical studies. Nevertheless, there is limited information on the cardiovascular actions of these agents in patients with diabetes and established cardiovascular disease. Hence, a more complete understanding of the cardiovascular risk:benefit ratio of incretin-based therapies will require completion of long term cardiovascular outcome studies currently underway in patients with T2DM. PMID:22323472

Ussher, John R.; Drucker, Daniel J.

2012-01-01

48

Biofluid Dynamics in Cardiovascular System  

NASA Astrophysics Data System (ADS)

Biofluid dynamics is characterized by the study of fluids in biological systems. Common biofluid systems include blood flow in the cardiovascular system and airflow in the lungs. The mathematical modeling of blood flow through the complex geometry of a prosthetic heart valve is a difficult task. In such a problem the complex geometries of the valve must be modeled properly so that they can be studied numerically. The present analysis is performed on a disk-type prosthetic heart valve. The valve is assumed to be in the aortic position and observed the structure of the valve cage influence the flow field near an aortic valve. For the purpose of mathematical modeling, the laminar incompressible two-dimensional steady flow of a homogeneous Newtonian fluid with constant viscosity is assumed. The flow is considered during the greater part of systole when the valve is fully open. Convergent numerical solutions are obtained for Reynolds numbers of 30, 180, 900 and 4500. Stream function, horizontal velocity, vertical velocity and shear stress solutions are computed at every grid point.

Chung, Hansol; Yoo, Su Jung; Kyung, Richard

2011-11-01

49

Cardiovascular system effects of marijuana.  

PubMed

Marijuana and delta9-tetrahydrocannabinol (THC) increase heart rate, slightly increase supine blood pressure, and on occasion produce marked orthostatic hypotension. Cardiovascular effects in animals are different, with bradycardia and hypotension the most typical response. Cardiac output increases, and peripheral vascular resistance and maximum exercise performance decrease. Tolerance to most of the initial cardiovascular effects appears rapidly. With repeated exposure, supine blood pressure decreases slightly, orthostatic hypotension disappears, blood volume increases, heart rate slows, and circulatory responses to exercise and Valsalva maneuver are diminished, consistent with centrally mediated, reduced sympathetic, and enhanced parasympathetic activity. Receptor-mediated and probably nonneuronal sites of action account for cannabinoid effects. The endocannabinoid system appears important in the modulation of many vascular functions. Marijuana's cardiovascular effects are not associated with serious health problems for most young, healthy users, although occasional myocardial infarction, stroke, and other adverse cardiovascular events are reported. Marijuana smoking by people with cardiovascular disease poses health risks because of the consequences of the resulting increased cardiac work, increased catecholamine levels, carboxyhemoglobin, and postural hypotension. PMID:12412837

Jones, Reese T

2002-11-01

50

The heart and cardiovascular system  

SciTech Connect

This book contains 72 chapters. Some of the chapter titles are: Nuclear Magnetic Resonance; Radionuclide Methods to Assess Cardiac Function, Perfusion Viability and Necrosis; NMR Imaging of the Cardiovascular System; Quantitative Angiographic Techniques; RNA Transcription in Heart Muscle; Reentry Rhythms; and Effect of Ischemia on Cardiac Electrophysiology.

Fozzard, H.A. (Univ. of Chicago, Chicago, IL (US)); Haber, E. (Harvard Medical School, Massachusetts General Hospital, Boston, MA (US)); Jennings, R.B. (Duke Univ. Medical Center, Durham, NC (US)); Katz, A.M. (Univ. of Connecticut School of Medicine, Farmington, CT (US))

1986-01-01

51

Bioengineering and the cardiovascular system  

PubMed Central

The development of the modern era of bioengineering and the advances in our understanding of the cardiovascular system have been intertwined over the past one-half century. This is true of bioengineering as an area for research in universities. Bioengineering is ultimately the beginning of a new engineering discipline, as well as a new discipline in the medical device industry. PMID:24688999

Nerem, Robert M

2013-01-01

52

The Gross Physiology of the Cardiovascular System  

NSDL National Science Digital Library

This site is the online text of Dr. Robert M. Anderson's book The Gross Physiology of the Cardiovascular System. Even though biomedical knowledge is continually advancing and becoming more specific, Anderson feels that it is important to "have a clear understanding of the gross mechanical function of the cardiovascular system as a whole." This resource is provided as a model to do just that. The text is well organized and easy to navigate; additionally, a video that provides a summary of the online text can be viewed online.

Anderson, Robert M.

53

Closed-loop real-time simulation model of hemodynamics and oxygen transport in the cardiovascular system  

PubMed Central

Background Computer technology enables realistic simulation of cardiovascular physiology. The increasing number of clinical surgical and medical treatment options imposes a need for better understanding of patient-specific pathology and outcome prediction. Methods A distributed lumped parameter real-time closed-loop model with 26 vascular segments, cardiac modelling with time-varying elastance functions and gradually opening and closing valves, the pericardium, intrathoracic pressure, the atrial and ventricular septum, various pathological states and including oxygen transport has been developed. Results Model output is pressure, volume, flow and oxygen saturation from every cardiac and vascular compartment. The model produces relevant clinical output and validation of quantitative data in normal physiology and qualitative directions in simulation of pathological states show good agreement with published data. Conclusion The results show that it is possible to build a clinically relevant real-time computer simulation model of the normal adult cardiovascular system. It is suggested that understanding qualitative interaction between physiological parameters in health and disease may be improved by using the model, although further model development and validation is needed for quantitative patient-specific outcome prediction. PMID:23842033

2013-01-01

54

Cardiovascular-Respiratory HUT Model including Optimal Control and Comparison to LBNP models  

E-print Network

introduces a model of the cardiovascular and respiratory system which is used to simulate orthostatic stress;2 CONTENTS Contents Contents 2 1 Physiology 3 1.1 General cardiovascular and respiratory system functionCardiovascular-Respiratory HUT Model including Optimal Control and Comparison to LBNP models Martin

Batzel, Jerry

55

Cardiovascular-Respiratory HUT Model including Optimal Control and Comparison to LBNP models  

E-print Network

introduces a model of the cardiovascular and respiratory system which is used to simulate orthostatic stress CONTENTS Contents Contents 2 1 Physiology 3 1.1 General cardiovascular and respiratory system functionCardiovascular-Respiratory HUT Model including Optimal Control and Comparison to LBNP models Martin

Batzel, Jerry

56

Cardiovascular system simulation in biomedical engineering education.  

NASA Technical Reports Server (NTRS)

Use of complex cardiovascular system models, in conjunction with a large hybrid computer, in biomedical engineering courses. A cardiovascular blood pressure-flow model, driving a compartment model for the study of dye transport, was set up on the computer for use as a laboratory exercise by students who did not have the computer experience or skill to be able to easily set up such a simulation involving some 27 differential equations running at 'real time' rate. The students were given detailed instructions regarding the model, and were then able to study effects such as those due to septal and valve defects upon the pressure, flow, and dye dilution curves. The success of this experiment in the use of involved models in engineering courses was such that it seems that this type of laboratory exercise might be considered for use in physiology courses as an adjunct to animal experiments.

Rideout, V. C.

1972-01-01

57

Cardiovascular disease in systemic sclerosis  

PubMed Central

Cardiovascular (CV) system involvement is a frequent complication of autoimmune diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). It still remains unclear if a premature atherosclerosis (ATS) occurs even in systemic sclerosis (SSc). Although microvascular disease is a hallmark of SSc, in the last few years a number of studies highlighted a higher prevalence of macrovascular disease in SSc patients in comparison to healthy individuals and these data have been correlated with a poorer prognosis. The mechanisms promoting ATS in SSc are not fully understood, but it is believed to be secondary to multi-system organ inflammation, endothelial wall damage and vasculopathy. Both traditional risk factors and endothelial dysfunction have been proposed to participate to the onset and progression of ATS in such patients. In particular, endothelial cell injury induced by anti-endothelial antibodies, ischemia/reperfusion damage, immune-mediated cytotoxicity represent the main causes of vascular injury together with an impaired vascular repair mechanism that determine a defective vasculogenesis. Aim of this review is to analyse both causes and clinical manifestations of macrovascular involvement and ATS in SSc. PMID:25705640

Cannarile, Francesca; Valentini, Valentina; Mirabelli, Giulia; Alunno, Alessia; Terenzi, Riccardo; Luccioli, Filippo; Bartoloni, Elena

2015-01-01

58

Cardiovascular disease in systemic sclerosis.  

PubMed

Cardiovascular (CV) system involvement is a frequent complication of autoimmune diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). It still remains unclear if a premature atherosclerosis (ATS) occurs even in systemic sclerosis (SSc). Although microvascular disease is a hallmark of SSc, in the last few years a number of studies highlighted a higher prevalence of macrovascular disease in SSc patients in comparison to healthy individuals and these data have been correlated with a poorer prognosis. The mechanisms promoting ATS in SSc are not fully understood, but it is believed to be secondary to multi-system organ inflammation, endothelial wall damage and vasculopathy. Both traditional risk factors and endothelial dysfunction have been proposed to participate to the onset and progression of ATS in such patients. In particular, endothelial cell injury induced by anti-endothelial antibodies, ischemia/reperfusion damage, immune-mediated cytotoxicity represent the main causes of vascular injury together with an impaired vascular repair mechanism that determine a defective vasculogenesis. Aim of this review is to analyse both causes and clinical manifestations of macrovascular involvement and ATS in SSc. PMID:25705640

Cannarile, Francesca; Valentini, Valentina; Mirabelli, Giulia; Alunno, Alessia; Terenzi, Riccardo; Luccioli, Filippo; Gerli, Roberto; Bartoloni, Elena

2015-01-01

59

Efficacy of Female Rat Models in Translational Cardiovascular Aging Research  

PubMed Central

Cardiovascular disease is the leading cause of death in women in the United States. Aging is a primary risk factor for the development of cardiovascular disease as well as cardiovascular-related morbidity and mortality. Aging is a universal process that all humans undergo; however, research in aging is limited by cost and time constraints. Therefore, most research in aging has been done in primates and rodents; however it is unknown how well the effects of aging in rat models translate into humans. To compound the complication of aging gender has also been indicated as a risk factor for various cardiovascular diseases. This review addresses the systemic pathophysiology of the cardiovascular system associated with aging and gender for aging research with regard to the applicability of rat derived data for translational application to human aging. PMID:25610649

Rice, K. M.; Fannin, J. C.; Gillette, C.; Blough, E. R.

2014-01-01

60

A multi-scale cardiovascular system model can account for the load-dependence of the end-systolic pressure-volume relationship  

PubMed Central

Background The end-systolic pressure-volume relationship is often considered as a load-independent property of the heart and, for this reason, is widely used as an index of ventricular contractility. However, many criticisms have been expressed against this index and the underlying time-varying elastance theory: first, it does not consider the phenomena underlying contraction and second, the end-systolic pressure volume relationship has been experimentally shown to be load-dependent. Methods In place of the time-varying elastance theory, a microscopic model of sarcomere contraction is used to infer the pressure generated by the contraction of the left ventricle, considered as a spherical assembling of sarcomere units. The left ventricle model is inserted into a closed-loop model of the cardiovascular system. Finally, parameters of the modified cardiovascular system model are identified to reproduce the hemodynamics of a normal dog. Results Experiments that have proven the limitations of the time-varying elastance theory are reproduced with our model: (1) preload reductions, (2) afterload increases, (3) the same experiments with increased ventricular contractility, (4) isovolumic contractions and (5) flow-clamps. All experiments simulated with the model generate different end-systolic pressure-volume relationships, showing that this relationship is actually load-dependent. Furthermore, we show that the results of our simulations are in good agreement with experiments. Conclusions We implemented a multi-scale model of the cardiovascular system, in which ventricular contraction is described by a detailed sarcomere model. Using this model, we successfully reproduced a number of experiments that have shown the failing points of the time-varying elastance theory. In particular, the developed multi-scale model of the cardiovascular system can capture the load-dependence of the end-systolic pressure-volume relationship. PMID:23363818

2013-01-01

61

The Gross Physiology of the Cardiovascular System  

NSDL National Science Digital Library

A global analysis of the mechanical function of the cardiovascular system that explains fundamental concepts, such as: The unique hydraulic characteristics of the heart as a pump and the cardiovascular system; the determinants of cardiac output; the mechanism that maintains blood volume equilibrium between the systemic and pulmonary circuits; and the primary contribution of the atria to circulation rate. Free downloadable text and online video available.

Dr. Robert M Anderson (University of Arizona)

2012-01-20

62

Cardiovascular Toxicities from Systemic Breast Cancer Therapy  

PubMed Central

Cardiovascular toxicity is unfortunately a potential short- or long-term sequela of breast cancer therapy. Both conventional chemotherapeutic agents such as anthracyclines and newer targeted agents such as trastuzumab can cause varying degrees of cardiac dysfunction. Type I cardiac toxicity is dose-dependent and irreversible, whereas Type II is not dose-dependent and is generally reversible with cessation of the drug. In this review, we discuss what is currently known about the cardiovascular effects of systemic breast cancer treatments, with a focus on the putative mechanisms of toxicity, the role of biomarkers, and potential methods of preventing and minimizing cardiovascular complications. PMID:25538891

Guo, Shuang; Wong, Serena

2014-01-01

63

A mathematical model of cardiovascular response to dynamic exercise  

Microsoft Academic Search

A mathematical model of cardiovascular response to dynamic exercise is presented. The model includes the pulsating heart, the systemic and pulmonary circulation, a functional description of muscle exercise hyperemia, the mechanical effects of muscle contractions on hemodynamics, and various neural regulatory mechanisms working on systemic resistance, venous unstressed volume, heart rate and ventricle contractility. These mechanisms comprehend the direct effect

E. Magosso; A. Felicani; M. Ursino

2001-01-01

64

MODELING CARDIOVASCULAR AND RESPIRATORY DYNAMICS IN CONGESTIVE HEART FAILURE  

E-print Network

MODELING CARDIOVASCULAR AND RESPIRATORY DYNAMICS IN CONGESTIVE HEART FAILURE LAURA M. ELLWEIN1 heart failure. The model is a lumped parameter model giving rise to a system of ordinary differential physiologically reasonable for a patient with congestive heart failure. 1. Introduction. The strong

Olufsen, Mette Sofie

65

Feedback control of mean aortic pressure in a dynamic model of the cardiovascular system.  

PubMed

Orbital measurements of the cardiac function of Space Shuttle crew members have shown an initial increase in cardiac stroke volume upon entry into weightlessness, followed by a gradual reduction in stroke volume to a level approximately 15% less than preflight values. In an effort to explain this response, it was hypothesized that gravity plays a role in cardiac filling. A mock circulatory system was designed to investigate this effect. Preliminary studies carried out with this system on the NASA KC-135 aircraft, which provides brief periods of weightlessness, showed a strong correlation between cardiac filling, stroke volume, and the presence or absence of gravity. The need for extended periods of high quality zero gravity was identified to verify this observation. To accomplish this, the aircraft version of the experiment was reduced in size and fully automated for eventual integration into a Get Away Special canister to conduct an orbital version of the experiment. This article describes the automated system, as well as the development and implementation of a control algorithm for the servoregulation of the mean aortic pressure in the orbital experiment. Three nonlinearities that influence the ability of the apparatus to regulate to a mean aortic pressure of 95 mm Hg were identified and minimized. In preparation for a Space Shuttle flight, the successful function of the servoregulatory scheme was demonstrated during ground tests and additional test flights aboard the KC-135. The control algorithm was successful in carrying out the experimental protocol, including regulation of mean aortic pressure. The algorithm could also be used for the automated operation of long-term tests of circulatory support systems, which may require a scheduled cycling of the pumping conditions on a daily basis. PMID:10593691

O'Leary, D S; Pantalos, G M; Sharp, M K

1999-01-01

66

Evaluating the Hemodynamical Response of a Cardiovascular System under Support of a Continuous Flow Left Ventricular Assist Device via Numerical Modeling and Simulations  

PubMed Central

Dilated cardiomyopathy is the most common type of the heart failure which can be characterized by impaired ventricular contractility. Mechanical circulatory support devices were introduced into practice for the heart failure patients to bridge the time between the decision to transplant and the actual transplantation which is not sufficient due to the state of donor organ supply. In this study, the hemodynamic response of a cardiovascular system that includes a dilated cardiomyopathic heart under support of a newly developed continuous flow left ventricular assist device—Heart Turcica Axial—was evaluated employing computer simulations. For the evaluation, a numerical model which describes the pressure-flow rate relations of Heart Turcica Axial, a cardiovascular system model describing the healthy and pathological hemodynamics, and a baroreflex model regulating the heart rate were used. Heart Turcica Axial was operated between 8000?rpm and 11000?rpm speeds with 1000?rpm increments for assessing the pump performance and response of the cardiovascular system. The results also give an insight about the range of the possible operating speeds of Heart Turcica Axial in a clinical application. Based on the findings, operating speed of Heart Turcica Axial should be between 10000?rpm and 11000?rpm. PMID:24363780

Safak, Koray K.

2013-01-01

67

Role of TRP channels in the cardiovascular system.  

PubMed

The transient receptor potential (TRP) superfamily consists of a large number of nonselective cation channels with variable degree of Ca(2+)-permeability. The 28 mammalian TRP channel proteins can be grouped into six subfamilies: canonical, vanilloid, melastatin, ankyrin, polycystic, and mucolipin TRPs. The majority of these TRP channels are expressed in different cell types including both excitable and nonexcitable cells of the cardiovascular system. Unlike voltage-gated ion channels, TRP channels do not have a typical voltage sensor, but instead can sense a variety of other stimuli including pressure, shear stress, mechanical stretch, oxidative stress, lipid environment alterations, hypertrophic signals, and inflammation products. By integrating multiple stimuli and transducing their activity to downstream cellular signal pathways via Ca(2+) entry and/or membrane depolarization, TRP channels play an essential role in regulating fundamental cell functions such as contraction, relaxation, proliferation, differentiation, and cell death. With the use of targeted deletion and transgenic mouse models, recent studies have revealed that TRP channels are involved in numerous cellular functions and play an important role in the pathophysiology of many diseases in the cardiovascular system. Moreover, several TRP channels are involved in inherited diseases of the cardiovascular system. This review presents an overview of current knowledge concerning the physiological functions of TRP channels in the cardiovascular system and their contributions to cardiovascular diseases. Ultimately, TRP channels may become potential therapeutic targets for cardiovascular diseases. PMID:25416190

Yue, Zhichao; Xie, Jia; Yu, Albert S; Stock, Jonathan; Du, Jianyang; Yue, Lixia

2015-02-01

68

Cardiovascular Interactions: An Interactive Tutorial and Mathematical Model  

NSDL National Science Digital Library

The maintenance of an adequate cardiac output and systemic arterial blood pressure is a complex process with intricacies that are often difficult to understand. Cardiovascular Interactions is an active learning tool that demonstrates the interactions between the functions of the heart and peripheral circulation. This learning package consists of a Lab Book, a Model, and an Information file. The Lab Book is an interactive tutorial for exploring the relative influences of parameter changes on the cardiovascular system under normal, stressful, or pathophysiological conditions. The learners are guided to predict the direction and relative magnitude of changes of key variables in the cardiovascular system, evaluate the accuracy of their predictions, and describe the cause-and-effect mechanisms involved. Consequences of heart failure, hemorrhage, exercise, and changes in intrathoracic pressure can be explored. The results obtained in the Lab Book are based on a five-compartment mathematical Model, which reflects our current understanding of the basic control of the cardiovascular system. The Model was designed to be complex enough to be realistic, yet not so complex as to be overwhelming. An Information File contains definitions and descriptions of classical physiology about key concepts, including figures, and a detailed description of the Model. Hypertext tags embedded in the Lab Book are used to access the Information File. The Cardiovascular Interactions learning package was designed to run from its CD and so does not need to be installed.

PhD Carl F. Rothe (Indiana University School of Medicine Department of Cellular and Integrative Physiology)

2002-06-01

69

A Population Model of Integrative Cardiovascular Physiology  

PubMed Central

We present a small integrative model of human cardiovascular physiology. The model is population-based; rather than using best fit parameter values, we used a variant of the Metropolis algorithm to produce distributions for the parameters most associated with model sensitivity. The population is built by sampling from these distributions to create the model coefficients. The resulting models were then subjected to a hemorrhage. The population was separated into those that lost less than 15 mmHg arterial pressure (compensators), and those that lost more (decompensators). The populations were parametrically analyzed to determine baseline conditions correlating with compensation and decompensation. Analysis included single variable correlation, graphical time series analysis, and support vector machine (SVM) classification. Most variables were seen to correlate with propensity for circulatory collapse, but not sufficiently to effect reasonable classification by any single variable. Time series analysis indicated a single significant measure, the stressed blood volume, as predicting collapse in situ, but measurement of this quantity is clinically impossible. SVM uncovered a collection of variables and parameters that, when taken together, provided useful rubrics for classification. Due to the probabilistic origins of the method, multiple classifications were attempted, resulting in an average of 3.5 variables necessary to construct classification. The most common variables used were systemic compliance, baseline baroreceptor signal strength and total peripheral resistance, providing predictive ability exceeding 90%. The methods presented are suitable for use in any deterministic mathematical model. PMID:24058546

Pruett, William A.; Husband, Leland D.; Husband, Graham; Dakhlalla, Muhammad; Bellamy, Kyle; Coleman, Thomas G.; Hester, Robert L.

2013-01-01

70

Verification of a computational cardiovascular system model comparing the hemodynamics of a continuous flow to a synchronous valveless pulsatile flow left ventricular assist device  

PubMed Central

The purpose of this investigation is to utilize a computational model to compare a synchronized valveless pulsatile left ventricular assist device to continuous flow left ventricular assist devices at the same level of device flow, and to verify the model with in vivo porcine data. A dynamic system model of the human cardiovascular system was developed to simulate support of a healthy or failing native heart from a continuous flow left ventricular assist device or a synchronous, pulsatile, valveless, dual piston positive displacement pump. These results were compared to measurements made during in vivo porcine experiments. Results from the simulation model and from the in vivo counterpart show that the pulsatile pump provides higher cardiac output, left ventricular unloading, cardiac pulsatility, and aortic valve flow as compared to the continuous flow model at the same level of support. The dynamic system model developed for this investigation can effectively simulate human cardiovascular support by a synchronous pulsatile or continuous flow ventricular assist device. PMID:23438771

Gohean, Jeffrey R.; George, Mitchell J.; Pate, Thomas D.; Kurusz, Mark; Longoria, Raul G.; Smalling, Richard W.

2012-01-01

71

The Heart of Our Cardiovascular System  

NSDL National Science Digital Library

Students learn about the heart and its role at the center of the human cardiovascular system. In the associated activity, students play out a scenario in which they are biomedical engineers asked to design artificial hearts. They learn about the path of blood flow through the heart and use that knowledge to evaluate designs of artificial hearts on the market.

Bio-Inspired Technology and Systems (BITS) RET,

72

Effect of Photochemotherapy on the Cardiovascular System  

Microsoft Academic Search

The effect of PUVA therapy on the cardiovascular system was studied in 2 groups of patients. The first group consisted of 9 otherwise healthy patients, who were treated without airconditioning. The second group was formed by 15 otherwise healthy psoriasis patients, who were treated with photochemotherapy, using airconditioning. In both groups the cabinet-skin and rectal temperature rose significantly. The most

E. P. Prens; G. Smeenk

1983-01-01

73

Magnetic resonance imaging and spectroscopy of the murine cardiovascular system  

PubMed Central

Magnetic resonance imaging (MRI) has emerged as a powerful and reliable tool to noninvasively study the cardiovascular system in clinical practice. Because transgenic mouse models have assumed a critical role in cardiovascular research, technological advances in MRI have been extended to mice over the last decade. These have provided critical insights into cardiac and vascular morphology, function, and physiology/pathophysiology in many murine models of heart disease. Furthermore, magnetic resonance spectroscopy (MRS) has allowed the nondestructive study of myocardial metabolism in both isolated hearts and in intact mice. This article reviews the current techniques and important pathophysiological insights from the application of MRI/MRS technology to murine models of cardiovascular disease. PMID:23292717

Akki, Ashwin; Gupta, Ashish

2013-01-01

74

Modelling of long-term and short-term mechanisms of arterial pressure control in the cardiovascular system: an object-oriented approach.  

PubMed

A mathematical model that provides an overall description of both the short- and long-term mechanisms of arterial pressure regulation is presented. Short-term control is exerted through the baroreceptor reflex while renal elimination plays a role in long-term control. Both mechanisms operate in an integrated way over the compartmental model of the cardiovascular system. The whole system was modelled in MODELICA, which uses a hierarchical object-oriented modelling strategy, under the DYMOLA simulation environment. The performance of the controlled system was analysed by simulation in light of the existing hypothesis and validation tests previously performed with physiological data, demonstrating the effectiveness of both regulation mechanisms under physiological and pathological conditions. PMID:24561348

Fernandez de Canete, J; Luque, J; Barbancho, J; Munoz, V

2014-04-01

75

Stochastic dynamics of the cardiovascular system  

NASA Astrophysics Data System (ADS)

The human cardiovascular system (CVS), responsible for the delivery of nutrients and removal of waste products to/from the entire body, is a highly complex system involving many control mechanisms. Signals derived from the CVS are inherently difficult to analyse because they are noisy, time-varying, and of necessarily limited duration. The application of techniques drawn from nonlinear science has, however, yielded many insights into the nature of the CVS, and has provided strong evidence for a large degree of determinism in the way it functions. Yet there is compelling evidence that random fluctuations (noise) also play an essential role. There are at least five oscillatory processes of widely differing frequency involved in the blood distribution. The evidence for them, and their probable physiological origins, are discussed. Interactions between some of the processes can give rise to modulation and synchronization phenomena, very similar to those observed in classical oscillators in many areas of physics. The extent to which the CVS can be modelled as a stochastic nonlinear dynamical system is reviewed, and future research directions and possible applications based on this perception are considered.

McClintock, Peter V. E.; Stefanovska, Aneta

2004-05-01

76

Modeling and simulating human cardiovascular response to acceleration  

E-print Network

The human cardiovascular system routinely encounters conditions that cause it to adapt. For example, when an astronaut enters microgravity, his/her cardiovascular system adapts rapidly to the weightless environment with ...

Zamanian, Sam Ahmad

2007-01-01

77

Mathematical biomarkers for the autonomic regulation of cardiovascular system  

PubMed Central

Heart rate and blood pressure are the most important vital signs in diagnosing disease. Both heart rate and blood pressure are characterized by a high degree of short term variability from moment to moment, medium term over the normal day and night as well as in the very long term over months to years. The study of new mathematical algorithms to evaluate the variability of these cardiovascular parameters has a high potential in the development of new methods for early detection of cardiovascular disease, to establish differential diagnosis with possible therapeutic consequences. The autonomic nervous system is a major player in the general adaptive reaction to stress and disease. The quantitative prediction of the autonomic interactions in multiple control loops pathways of cardiovascular system is directly applicable to clinical situations. Exploration of new multimodal analytical techniques for the variability of cardiovascular system may detect new approaches for deterministic parameter identification. A multimodal analysis of cardiovascular signals can be studied by evaluating their amplitudes, phases, time domain patterns, and sensitivity to imposed stimuli, i.e., drugs blocking the autonomic system. The causal effects, gains, and dynamic relationships may be studied through dynamical fuzzy logic models, such as the discrete-time model and discrete-event model. We expect an increase in accuracy of modeling and a better estimation of the heart rate and blood pressure time series, which could be of benefit for intelligent patient monitoring. We foresee that identifying quantitative mathematical biomarkers for autonomic nervous system will allow individual therapy adjustments to aim at the most favorable sympathetic-parasympathetic balance. PMID:24109456

Campos, Luciana A.; Pereira, Valter L.; Muralikrishna, Amita; Albarwani, Sulayma; Brás, Susana; Gouveia, Sónia

2013-01-01

78

Clinical models of cardiovascular regulation after weightlessness  

NASA Technical Reports Server (NTRS)

After several days in microgravity, return to earth is attended by alterations in cardiovascular function. The mechanisms underlying these effects are inadequately understood. Three clinical disorders of autonomic function represent possible models of this abnormal cardiovascular function after spaceflight. They are pure autonomic failure, baroreflex failure, and orthostatic intolerance. In pure autonomic failure, virtually complete loss of sympathetic and parasympathetic function occurs along with profound and immediate orthostatic hypotension. In baroreflex failure, various degrees of debuffering of blood pressure occur. In acute and complete baroreflex failure, there is usually severe hypertension and tachycardia, while with less complete and more chronic baroreflex impairment, orthostatic abnormalities may be more apparent. In orthostatic intolerance, blood pressure fall is minor, but orthostatic symptoms are prominent and tachycardia frequently occurs. Only careful autonomic studies of human subjects in the microgravity environment will permit us to determine which of these models most closely reflects the pathophysiology brought on by a period of time in the microgravity environment.

Robertson, D.; Jacob, G.; Ertl, A.; Shannon, J.; Mosqueda-Garcia, R.; Robertson, R. M.; Biaggioni, I.

1996-01-01

79

Estimation of cardiac output and systemic vascular resistance using a multivariate regression model with features selected from the finger photoplethysmogram and routine cardiovascular measurements  

PubMed Central

Background Cardiac output (CO) and systemic vascular resistance (SVR) are two important parameters of the cardiovascular system. The ability to measure these parameters continuously and noninvasively may assist in diagnosing and monitoring patients with suspected cardiovascular diseases, or other critical illnesses. In this study, a method is proposed to estimate both the CO and SVR of a heterogeneous cohort of intensive care unit patients (N=48). Methods Spectral and morphological features were extracted from the finger photoplethysmogram, and added to heart rate and mean arterial pressure as input features to a multivariate regression model to estimate CO and SVR. A stepwise feature search algorithm was employed to select statistically significant features. Leave-one-out cross validation was used to assess the generalized model performance. The degree of agreement between the estimation method and the gold standard was assessed using Bland-Altman analysis. Results The Bland-Altman bias ±precision (1.96 times standard deviation) for CO was -0.01 ±2.70 L min-1 when only photoplethysmogram (PPG) features were used, and for SVR was -0.87 ±412 dyn.s.cm-5 when only one PPG variability feature was used. Conclusions These promising results indicate the feasibility of using the method described as a non-invasive preliminary diagnostic tool in supervised or unsupervised clinical settings. PMID:23452705

2013-01-01

80

A clinical decision support system prototype for cardiovascular intensive care  

Microsoft Academic Search

This paper describes the development and validation of a decision-support system prototype that can help manage hypovolemic\\u000a hypotension in the Cardiovascular Intensive Care Unit (CVICU). The prototype uses physiologic pattern-matching, therapeutic\\u000a protocols, computational drug-dosage response modeling and expert reasoning heuristics in its selection of intervention strategies\\u000a and choices. As part of model testing, the prototype simulated real-time operation by processing

Francis Lau

1994-01-01

81

Cardiovascular response to dynamic aerobic exercise: A methematical model  

Microsoft Academic Search

An original mathematical model of the cardiovascular response to dynamic exercise is presented. It includes the pulsating\\u000a heart, the pulmonary and systemic circulation, a separate description of the vascular bed in active tissues, the local metabolic\\u000a vasodilation in these tissues and the mechanical effects of muscular contractions on venous return. Moreover, the model provides\\u000a a description of the ventilatory response

E. Magosso; M. Ursino

2002-01-01

82

Proteome analysis in cardiovascular pathophysiology using Dahl rat model  

Microsoft Academic Search

Dahl salt-sensitive (DS) and salt-resistant (DR) inbred rat strains represent a well established animal model for cardiovascular research. Upon prolonged administration of high-salt-containing diet, DS rats develop systemic hypertension, and as a consequence they develop left ventricular hypertrophy, followed by heart failure.The aim of this work was to explore whether this animal model is suitable to identify biomarkers that characterize

Thomas Grussenmeyer; Silvia Meili-Butz; Volker Roth; Thomas Dieterle; Marijke Brink; Bernhard Winkler; Peter Matt; Thierry P. Carrel; Friedrich S. Eckstein; Ivan Lefkovits; Martin T. R. Grapow

2011-01-01

83

Molecular targets of tea polyphenols in the cardiovascular system  

Microsoft Academic Search

Tea-derived polyphenols have attracted considerable attention in the prevention of cancer and cardiovascular diseases. In comparison to tumour cells, the elucidation of their molecular targets in cardiovascular relevant cells is still at the beginning. Although promising experimental and clinical data demonstrate protective effects for the cardiovascular system, little information is actually available on how these beneficial effects of tea polyphenols

Verena Stangl; Henryk Dreger; Karl Stangl; Mario Lorenz

2007-01-01

84

A Pulsatile Cardiovascular Computer Model for Teaching Heart-Blood Vessel Interaction.  

ERIC Educational Resources Information Center

Describes a model which gives realistic predictions of pulsatile pressure, flow, and volume events in the cardiovascular system. Includes computer oriented laboratory exercises for veterinary and graduate students; equations of the dynamic and algebraic models; and a flow chart for the cardiovascular teaching program. (JN)

Campbell, Kenneth; And Others

1982-01-01

85

A wave dynamics criterion for optimization of mammalian cardiovascular system.  

PubMed

The cardiovascular system in mammals follows various optimization criteria covering the heart, the vascular network, and the coupling of the two. Through a simple dimensional analysis we arrived at a non-dimensional number (wave condition number) that can predict the optimum wave state in which the left ventricular (LV) pulsatile power (LV workload) is minimized in a mammalian cardiovascular system. This number is also universal among all mammals independent of animal size maintaining a value of around 0.1. By utilizing a unique in vitro model of human aorta, we tested our hypothesis against a wide range of aortic compliance (pulse wave velocity). We concluded that the optimum value of the wave condition number remains to be around 0.1 for a wide range of aorta compliance that we could simulate in our in-vitro system. PMID:24642352

Pahlevan, Niema M; Gharib, Morteza

2014-05-01

86

Physiological homology between Drosophila melanogaster and vertebrate cardiovascular systems  

E-print Network

The physiology of the Drosophila melanogaster cardiovascular system remains poorly characterized compared with its vertebrate counterparts. Basic measures of physiological performance remain unknown. It also is unclear ...

Choma, Michael A.

87

Space weather and cardiovascular system. New findings  

NASA Astrophysics Data System (ADS)

Researches of last two decades have shown that the cardiovascular system represents the most probable target for influence of helio - and geomagnetic activity. Both cardiovascular system and system of blood are connected very closely: one system cannot exist without another. For the same reason the effects perceived by one system, are easily transferred to another. Laboratory tests such as blood coagulation, platelet aggregation, and capillary blood velocity (CBV) performed in Scientific Clinical Center JSC "Russian Railways in patients suffering from coronary heart disease (CHD) revealed a high dependence with a level of geomagnetic activity. Results of these and other findings allow to assume that blood itself can be a sensor of geomagnetic fields variations because erythrocytes, platelets, and leucocytes bearing electric charge on membranes, and in a comparable magnetic field can change as own properties and properties of blood flow. It is interesting that not only geomagnetic disturbances, but also the periods of very quiet geomagnetic conditions affect a capillary blood velocity, slowing down it. It was shown during long-term experiment with isolation named 'MARS-500' in spatial facility of the Institute of Biomedical Problems in Moscow as imitation of an extended space mission to Mars. Using digital capillaroscope 'Russia', two crewmembers - medical doctors made records of microcirculation parameters at themselves and other four participants of 'Martian' team. Capillary records were performed before, during, and after period of isolation in medical module of MARS-500 facility. At the period of experiment nobody of crewmembers knew about real geomagnetic conditions. In days of active geomagnetic conditions average CBV has registered as 389 ± 167 ?m/s, that statistically significant (p

Gurfinkel, Yury; Breus, Tamara

2014-05-01

88

Degradation Model of Bioabsorbable Cardiovascular Stents  

PubMed Central

This study established a numerical model to investigate the degradation mechanism and behavior of bioabsorbable cardiovascular stents. In order to generate the constitutive degradation material model, the degradation characteristics were characterized with user-defined field variables. The radial strength bench test and analysis were used to verify the material model. In order to validate the numerical degradation model, in vitro bench test and in vivo implantation studies were conducted under physiological and normal conditions. The results showed that six months of degradation had not influenced the thermodynamic properties and mechanical integrity of the stent while the molecular weight of the stents implanted in the in vivo and in vitro models had decreased to 61.8% and 68.5% respectively after six month's implantation. It was also found that the degradation rate, critical locations and changes in diameter of the stents in the numerical model were in good consistency in both in vivo and in vitro studies. It implies that the numerical degradation model could provide useful physical insights and prediction of the stent degradation behavior and evaluate, to some extent, the in-vivo performance of the stent. This model could eventually be used for design and optimization of bioabsorbable stent. PMID:25365310

Luo, Qiyi; Liu, Xiangkun; Li, Zhonghua; Huang, Chubo; Zhang, Wen; Meng, Juan; Chang, Zhaohua; Hua, Zezhao

2014-01-01

89

Predictions of cardiovascular responses during STS reentry using mathematical models  

NASA Technical Reports Server (NTRS)

The physiological adaptation to weightless exposure includes cardiovascular deconditioning arising in part from a loss of total circulating blood volume and resulting in a reduction of orthostatic tolerance. The crew of the Shuttle orbiter are less tolerant to acceleration forces in the head-to-foot direction during the reentry phase of the flight at a time they must function at a high level of performance. The factors that contribute to orthostatic intolerance during and following reentry and to predict the likelihood of impaired crew performance are evaluated. A computer simulation approach employing a mathematical model of the cardiovascular system is employed. It is shown that depending on the severity of blood volume loss, the reentry acceleration stress may be detrimental to physiologic function and may place the physiologic status of the crew near the borderline of some type of impairment. They are in agreement with conclusions from early ground-based experiments and from observations of early Shuttle flights.

Leonard, J. I.; Srinivasan, R.

1985-01-01

90

Regulation of sympathetic nervous system function after cardiovascular deconditioning  

NASA Technical Reports Server (NTRS)

Humans subjected to prolonged periods of bed rest or microgravity undergo deconditioning of the cardiovascular system, characterized by resting tachycardia, reduced exercise capability, and a predisposition for orthostatic intolerance. These changes in cardiovascular function are likely due to a combination of factors, including changes in control of body fluid balance or cardiac alterations resulting in inadequate maintenance of stroke volume, altered arterial or venous vascular function, reduced activation of cardiovascular hormones, and diminished autonomic reflex function. There is evidence indicating a role for each of these mechanisms. Diminished reflex activation of the sympathetic nervous system and subsequent vasoconstriction appear to play an important role. Studies utilizing the hindlimb-unloaded (HU) rat, an animal model of deconditioning, evaluated the potential role of altered arterial baroreflex control of the sympathetic nervous system. These studies indicate that HU results in blunted baroreflex-mediated activation of both renal and lumbar sympathetic nerve activity in response to a hypotensive stimulus. HU rats are less able to maintain arterial pressure during hemorrhage, suggesting that diminished ability to increase sympathetic activity has functional consequences for the animal. Reflex control of vasopressin secretion appears to be enhanced following HU. Blunted baroreflex-mediated sympathoexcitation appears to involve altered central nervous system function. Baroreceptor afferent activity in response to changes in arterial pressure is unaltered in HU rats. However, increases in efferent sympathetic nerve activity for a given decrease in afferent input are blunted after HU. This altered central nervous system processing of baroreceptor inputs appears to involve an effect at the rostral ventrolateral medulla (RVLM). Specifically, it appears that tonic GABAA-mediated inhibition of the RVLM is enhanced after HU. Augmented inhibition apparently arises from sources other than the caudal ventrolateral medulla. If similar alterations in control of the sympathetic nervous system occur in humans in response to cardiovascular deconditioning, it is likely that they play an important role in the observed tendency for orthostatic intolerance. Combined with potential changes in vascular function, cardiac function, and hypovolemia, the predisposition for orthostatic intolerance following cardiovascular deconditioning would be markedly enhanced by blunted ability to reflexly activate the sympathetic nervous system.

Hasser, E. M.; Moffitt, J. A.

2001-01-01

91

Systems-based approaches to cardiovascular disease  

Microsoft Academic Search

Common cardiovascular diseases, such as atherosclerosis and congestive heart failure, are exceptionally complex, involving a multitude of environmental and genetic factors that often show nonlinear interactions as well as being highly dependent on sex, age, and even the maternal environment. Although focused, reductionistic approaches have led to progress in elucidating the pathophysiology of cardiovascular diseases, such approaches are poorly powered

W. Robb MacLellan; Yibin Wang; Aldons J. Lusis

2012-01-01

92

Two-layered model of Casson fluid flow through stenotic blood vessels: applications to the cardiovascular system.  

PubMed

The effects of peripheral layer viscosity on physiological characteristics of blood flow through the artery with mild stenosis have been investigated. Blood has been represented by a two-fluid model, consisting of a core region of suspension of all the erythrocytes assumed to be a Casson fluid and a peripheral layer of plasma as a Newtonian fluid. The study is based on theoretical considerations and numerical evaluations and is restricted to the flow of blood through small arteries (130-1000 microns in diameter). It has been found that the resistance to flow and the wall shear stress decrease as the peripheral layer viscosity decreases. These characteristics are found to be decreasing as peripheral layer thickness increases. The numerical results show that the existence of the peripheral layer is helpful in functioning of the diseased arterial system. The analysis has been applied to calculate the resistance to flow and wall shear stress in different blood vessels. PMID:8063842

Srivastava, V P; Saxena, M

1994-07-01

93

Model-referenced cardiovascular circulatory simulator: construction and control.  

PubMed

Physiological feasibility is the most important requirement for cardiovascular circulatory simulators (CCSs). However, previous simulators have been validated by a comparison with specific human data sets, which are valid only for very limited conditions, and so it is difficult to validate the fidelity of a CCS for various body conditions. To overcome this critical limitation, we propose a model-referenced CCS that reproduces the behavior of an electrical-analog model of the cardiovascular circulatory system, for which physiological fidelity is well established over a wide range. In this study, the electrical-analog reference model was realized in the hardware simulator using fluidic element modeling and by the feedback control of a mock ventricle. The proposed simulator showed a good match with the reference model behavior, and its physiological validity was thereby verified. The proposed simulator is able to show responsiveness to various body conditions as well. To the best of the author's knowledge, this is the first report of an in vitro CCS verified to be consistent with reference model behavior. PMID:25345617

Gwak, Kwan-Woong

2015-04-01

94

Gravitational Force and the Cardiovascular System  

NASA Technical Reports Server (NTRS)

Cardiovascular responses to changes in gravitational force are considered. Man is ideally suited to his 1-g environment. Although cardiovascular adjustments are required to accommodate to postural changes and exercise, these are fully accomplished for short periods (min). More challenging stresses are those of short-term microgravity (h) and long-term microgravity (days) and of gravitational forces greater than that of Earth. The latter can be simulated in the laboratory and quantitative studies can be conducted.

Pendergast, D. R.; Olszowka, A. J.; Rokitka, M. A.; Farhi, L. E.

1991-01-01

95

Cardiovascular model for the simulation of exercise, lower body negative pressure, and tilt experiments  

NASA Technical Reports Server (NTRS)

A mathematical model and digital computer simulation of the human cardiovascular system and its controls have been developed to simulate pulsatile dynamic responses to the cardiovascular experiments of the Skylab missions and to selected physiological stresses of manned space flight. Specific model simulations of the bicycle ergometry, lower body negative pressure, and tilt experiments have been developed and verified for 1-g response by comparison with available experimental data. The zero-g simulations of two Skylab experiments are discussed.

Croston, R. C.; Fitzjerrell, D. G.

1974-01-01

96

Human thermoregulation and the cardiovascular system.  

PubMed

A key but little understood function of the cardiovascular system is to exchange heat between the internal body tissues, organs and the skin to maintain internal temperature within a narrow range in a variety of conditions that produce vast changes in external (exogenous) and/or internal (endogenous) thermal loads. Heat transfer via the flowing blood (i.e. vascular convective heat transfer) is the most important heat-exchange pathway inside the body. This pathway is particularly important when metabolic heat production increases many-fold during exercise. During exercise typical of many recreational and Olympic events, heat is transferred from the heat-producing contracting muscles to the skin surrounding the exercising limbs and to the normally less mobile body trunk and head via the circulating blood. Strikingly, a significant amount of heat produced by the contracting muscles is liberated from the skin of the exercising limbs. The local and central mechanisms regulating tissue temperature in the exercising limbs, body trunk and head are essential to avoid the deleterious consequences on human performance of either hyperthermia or hypothermia. This brief review focuses on recent literature addressing the following topics: (i) the dynamics of heat production in contracting skeletal muscle; (ii) the influence of exercise and environmental heat and cold stress on limb and systemic haemodynamics; and (iii) the impact of changes in muscle blood flow on heat exchange in human limbs. The paper highlights the need to investigate the responses and mechanisms of vascular convective heat exchange in exercising limbs to advance our understanding of local tissue temperature regulation during exercise and environmental stress. PMID:22227198

González-Alonso, José

2012-03-01

97

Thematic review series: Systems Biology Approaches to Metabolic and Cardiovascular Disorders. Network perspectives of cardiovascular metabolism  

Microsoft Academic Search

In this review, we examine cardiovascular metabo- lism from three different, but highly complementary, perspectives. First, from the abstract perspective of a me- tabolite network, composed of nodes and links. We present fundamental concepts in network theory, including emer- gence, to illustrate how nature has designed metabolism with a hierarchal modular scale-free topology to provide a robust system of energy

James N. Weiss; Ling Yang; Zhilin Qu

2006-01-01

98

A behavioral link between the oculomotor and cardiovascular systems  

Microsoft Academic Search

Although the eyes and the heart serve very different purposes, each receives autonomic innervation. Capitalizing on recent\\u000a theoretical and technological innovations in the understanding and assessment of oculomotor and cardiovascular behavior, three\\u000a experiments measured behavioral covariation between the oculomotor and cardiovascular systems. Measures of dark focus and\\u000a dark vergence indexed oculomotor tone, and the spectral decomposition of variations in heart

Richard A. Tyrrell; Julian F. Thayer; Bruce H. Friedman; Herschel W. Leibowitz; Ellie L. Francis

1995-01-01

99

The Role of Shear Stress on ET-1, KLF2, and NOS-3 Expression in the Developing Cardiovascular System of Chicken Embryos in a Venous Ligation Model  

NSDL National Science Digital Library

In this review, the role of wall shear stress in the chicken embryonic heart is analyzed to determine its effect on cardiac development through regulating gene expression. Therefore, background information is provided for fluid dynamics, normal chicken and human heart development, cardiac malformations, cardiac and vitelline blood flow, and a chicken model to induce cardiovascular anomalies. A set of endothelial shear stress-responsive genes coding for endothelin-1 (ET-1), lung Krüppel-like factor (LKLF/KLF2), and endothelial nitric oxide synthase (eNOS/NOS-3) are active in development and are specifically addressed.

2007-12-01

100

Physiological system integrations with emphasis on the respiratory-cardiovascular system  

NASA Technical Reports Server (NTRS)

The integration of two types of physiological system simulations is presented. The long term model is a circulatory system model which simulates long term blood flow variations and compartmental fluid shifts. The short term models simulate transient phenomena of the respiratory, thermoregulatory, and pulsatile cardiovascular systems as they respond to stimuli such as LBNP, exercise, and environmental gaseous variations. An overview of the interfacing approach is described. Descriptions of the variable interface for long term to short term and between the three short term models are given.

Gallagher, R. R.

1975-01-01

101

BE 508: Quantitative Studies of Respiratory and Cardiovascular Systems Spring Semester, 2013  

E-print Network

1 BE 508: Quantitative Studies of Respiratory and Cardiovascular Systems Spring Semester, 2013 of the respiratory system (1 lecture) (Bates, Ch 1) 2. Measurement of respiratory function (2 lectures) (Bates, Ch 2 in disease · Development of morphometric models of the respiratory system · Simulation of lung disease

Vajda, Sandor

102

Large Blood Vessels 1.1 Introduction --The Cardiovascular System  

E-print Network

Chapter 1 Large Blood Vessels 1.1 Introduction -- The Cardiovascular System The heart is a pump that circulates blood to the lungs for oxygenation (pul- monary circulation) and then throughout the systemic arterial system with a total cycle time of about one minute. From the left ventricle of the heart, blood

Luo, Xiaoyu

103

Cardiovascular and nervous system changes during meditation  

PubMed Central

Background: A number of benefits have been described for the long-term practice of meditation, yet little is known regarding the immediate neurological and cardiovascular responses to meditation. Wireless sensor technology allows, for the first time, multi-parameter and quantitative monitoring of an individual's responses during meditation. The present study examined inter-individual variations to meditation through continuous monitoring of EEG, blood pressure, heart rate and its variability (HRV) in novice and experienced meditators. Methods: Participants were 20 experienced and 20 novice meditators involved in a week-long wellness retreat. Monitoring took place during meditation sessions on the first and last full days of the retreat. All participants wore a patch that continuously streamed ECG data, while half of them also wore a wireless EEG headset plus a non-invasive continuous blood pressure monitor. Results: Meditation produced variable but characteristic EEG changes, significantly different from baseline, even among novice meditators on the first day. In addition, although participants were predominately normotensive, the mean arterial blood pressure fell a small (2–3 mmHg) but significant (p < 0.0001) amount during meditation. The effect of meditation on HRV was less clear and influenced by calculation technique and respiration. No clear relationship between EEG changes, HRV alterations, or mean blood pressure during meditation was found. Conclusion: This is the first study to investigate neurological and cardiovascular responses during meditation in both novice and experienced meditators using novel, wearable, wireless devices. Meditation produced varied inter-individual physiologic responses. These results support the need for further investigation of the short- and long-term cardiovascular effects of mental calm and individualized ways to achieve it. PMID:25852526

Steinhubl, Steven R.; Wineinger, Nathan E.; Patel, Sheila; Boeldt, Debra L.; Mackellar, Geoffrey; Porter, Valencia; Redmond, Jacob T.; Muse, Evan D.; Nicholson, Laura; Chopra, Deepak; Topol, Eric J.

2015-01-01

104

Bench to Bedside Primer: The Cardiovascular System and Heart Arrhythmia  

NSDL National Science Digital Library

This bench-to-bedside is a four-page Â?primerÂ? (a booklet of basic principles) that highlights cardiovascular physiology. This primer should be readable by your students or the general public to help inform them about the organ system, diseases that affect it, and basic and clinical research being done on it. It could also be used as a teaching model your students could follow in creating their own bench-to-beside primer.This teaching resource was developed by a K-12 science teacher in the American Physiological SocietyÂ?s 2011 Frontiers Online in Physiology Program. For more information on this program, please visit www.frontiersinphys.org.

Cora James (Haskell High School)

2011-10-07

105

Obesity May Shut Down Circadian Clock in the Cardiovascular System  

NSDL National Science Digital Library

Researchers at the Georgia Health Sciences University in Augusta have found that a master clock gene Â? which regulates the cardiovascular system Â? does not fluctuate regularly as it does in non-obese animals. This means that a key gene clock of the cardiovascular system does not work properly when obesity is present. These findings are believed to be the first of their kind. The study was conducted by Shuiqing Qiu, Eric Belin de Chantemele, James Mintz, David J. Fulton, R. Daniel Rudic and David W. Stepp.

APS Communications Office (American Physiological Society Communications Office)

2011-04-10

106

Recent advances in circadian rhythms in cardiovascular system  

PubMed Central

Growing evidence shows that intrinsic circadian clocks are tightly related to cardiovascular functions. The diurnal changes in blood pressure and heart rate are well known circadian rhythms. Endothelial function, platelet aggregation and thrombus formation exhibit circadian changes as well. The onset of many cardiovascular diseases (CVDs) or events, such as myocardial infarction, stroke, arrhythmia, and sudden cardiac death, also exhibits temporal trends. Furthermore, there is strong evidence from animal models and epidemiological studies showing that disruption of circadian rhythms is a significant risk factor for many CVDs, and the intervention of CVDs may have a time dependent effect. In this mini review, we summarized recent advances in our understanding of the relationship between circadian rhythm and cardiovascular physiology and diseases including blood pressure regulation and myocardial infarction.

Chen, Lihong; Yang, Guangrui

2015-01-01

107

Noise, radio frequency radiation and the cardiovascular system  

SciTech Connect

It is postulated that noise acting as an inducer of stress can produce widespread cardiovascular effects through the central nervous mechanism. As already documented, measurable changes are reported on blood pressure, circulating hormone levels and urinary catecholamine excretion, serum cholesterol and even platelet aggregation (in experimental animals). The majority of the studies are concerned with short-term effects in man and in animals, and data relating to long-term effects of noise on the cardiovascular system is not available. Further study is needed to determine the circumstances under which noise exposure produces increases in blood pressure and to define susceptible population groups. The relationship between noise exposure at specified levels and duration and the development of chronic established hypertension and cardiovascular disease can be explored.

Resnekov, L.

1981-01-01

108

Cardiovascular defects in a mouse model of HOXA1 syndrome  

E-print Network

artery (ASC), ventricular septal defect (VSD), bicuspid aortic valve (BAV) and Tetralogy of Fallot (7Cardiovascular defects in a mouse model of HOXA1 syndrome Nadja Makki and Mario R. Capecchi Howard is one of the most common human birth defects, yet many genes and pathways regulating heart development

Capecchi, Mario R.

109

Hydroxybenzoic acid isomers and the cardiovascular system.  

PubMed

Today we are beginning to understand how phytochemicals can influence metabolism, cellular signaling and gene expression. The hydroxybenzoic acids are related to salicylic acid and salicin, the first compounds isolated that have a pharmacological activity. In this review we examine how a number of hydroxyphenolics have the potential to ameliorate cardiovascular problems related to aging such as hypertension, atherosclerosis and dyslipidemia. The compounds focused upon include 2,3-dihydroxybenzoic acid (Pyrocatechuic acid), 2,5-dihydroxybenzoic acid (Gentisic acid), 3,4-dihydroxybenzoic acid (Protocatechuic acid), 3,5-dihydroxybenzoic acid (?-Resorcylic acid) and 3-monohydroxybenzoic acid. The latter two compounds activate the hydroxycarboxylic acid receptors with a consequence there is a reduction in adipocyte lipolysis with potential improvements of blood lipid profiles. Several of the other compounds can activate the Nrf2 signaling pathway that increases the expression of antioxidant enzymes, thereby decreasing oxidative stress and associated problems such as endothelial dysfunction that leads to hypertension as well as decreasing generalized inflammation that can lead to problems such as atherosclerosis. It has been known for many years that increased consumption of fruits and vegetables promotes health. We are beginning to understand how specific phytochemicals are responsible for such therapeutic effects. Hippocrates' dictum of 'Let food be your medicine and medicine your food' can now be experimentally tested and the results of such experiments will enhance the ability of nutritionists to devise specific health-promoting diets. PMID:24943896

Juurlink, Bernhard H J; Azouz, Haya J; Aldalati, Alaa M Z; AlTinawi, Basmah M H; Ganguly, Paul

2014-01-01

110

Acetaldehyde, polymorphisms and the cardiovascular system.  

PubMed

To date, the only genes that have been consistently replicated across racial and ethnic groups to influence alcoholism vulnerability are polymorphisms in the alcohol-metabolizing enzymes, i.e. cytosolic alcohol dehydrogenase 1B (ADH1B) and mitochondrial aldehyde dehydrogenase 2 (ALDH2). Both the variant ADHIB*2 and ALDH2*2 alleles significantly protect against developing alcoholism. The protection has been thought to result from accumulation of acetaldehyde after drinking. Unlike ALDH2*2, direct correlation between ADHI1B*2 and blood acetaldehyde has not been verified. ALDH2*2/*2 homozygosity appeared to almost completely protect against alcoholism, whereas ALDH2* 1/*2 heterozygosity appeared to reduce risk of the disease only about threefold. Direct correlations of blood ethanol and acetaldehyde concentrations, cardiovascular haemodynamic responses, and the subjective perceptions after challenge with low (0.2g/kg) to moderate (0.5g/kg) alcohol in individuals with different ALDH2 genotypes support the notion that full protection against alcoholism byALDH2*2/*2 may derive from either abstinence or deliberate moderation in alcohol consumption due to strong discomfort from physiological and psychological responses caused by persistently elevated blood acetaldehyde after ingestion of a small amount of alcohol, and that the partial protection by ALDH2*1/*2 can be ascribed to significantly lower acetaldehyde build-up in blood and the according adverse reactions. PMID:17590986

Yin, Shih-Jiun; Peng, Giia-Sheun

2007-01-01

111

Hydroxybenzoic acid isomers and the cardiovascular system  

PubMed Central

Today we are beginning to understand how phytochemicals can influence metabolism, cellular signaling and gene expression. The hydroxybenzoic acids are related to salicylic acid and salicin, the first compounds isolated that have a pharmacological activity. In this review we examine how a number of hydroxyphenolics have the potential to ameliorate cardiovascular problems related to aging such as hypertension, atherosclerosis and dyslipidemia. The compounds focused upon include 2,3-dihydroxybenzoic acid (Pyrocatechuic acid), 2,5-dihydroxybenzoic acid (Gentisic acid), 3,4-dihydroxybenzoic acid (Protocatechuic acid), 3,5-dihydroxybenzoic acid (?-Resorcylic acid) and 3-monohydroxybenzoic acid. The latter two compounds activate the hydroxycarboxylic acid receptors with a consequence there is a reduction in adipocyte lipolysis with potential improvements of blood lipid profiles. Several of the other compounds can activate the Nrf2 signaling pathway that increases the expression of antioxidant enzymes, thereby decreasing oxidative stress and associated problems such as endothelial dysfunction that leads to hypertension as well as decreasing generalized inflammation that can lead to problems such as atherosclerosis. It has been known for many years that increased consumption of fruits and vegetables promotes health. We are beginning to understand how specific phytochemicals are responsible for such therapeutic effects. Hippocrates’ dictum of ‘Let food be your medicine and medicine your food’ can now be experimentally tested and the results of such experiments will enhance the ability of nutritionists to devise specific health-promoting diets. PMID:24943896

2014-01-01

112

An allometric analysis of the giraffe cardiovascular system  

Microsoft Academic Search

There has been co-evolution of a long neck and high blood pressure in giraffes. How the cardiovascular system (CVS) has adapted to produce a high blood pressure, and how it compares with other similar sized mammals largely is unknown. We have measured body mass and heart structure in 56 giraffes of both genders ranging in body mass from 18kg to

G. Mitchell; J. D. Skinner

2009-01-01

113

Systemic Inflammation in Cardiovascular and Periodontal Disease: Comparative Study  

Microsoft Academic Search

Epidemiological studies have implicated periodontal disease (PD) as a risk factor for the development of cardiovascular disease (CVD). These studies addressed the premise that local infection may perturb the levels of systemic inflammatory mediators, thereby promoting mechanisms of atherosclerosis. Levels of inflammatory mediators in the sera of subjects with only PD, only CVD, both diseases, or neither condition were compared.

Ingrid Glurich; Sara Grossi; Boris Albini; Alex Ho; Rashesh Shah; Mohamed Zeid; Heinz Baumann; Robert J. Genco; Ernesto De Nardin

2002-01-01

114

Mutations affecting the formation and function of the cardiovascular system in the zebrafish embryo  

Microsoft Academic Search

Abstract As part of a large-scale mutagenesis screen of the zebrafish genome, we have identified 58 mutations that affect the formation and function of the cardiovascular system. The cardiovascular system is

J N Chen; M A Mohideen; L Solnica-Krezel; A F Schier; J Malicki

1996-01-01

115

Decadal Cycles in the Human Cardiovascular System.  

PubMed

Seven of the eight authors of this report each performed physiologic self-surveillance, some around the clock for decades. We here document the presence of long cycles (decadals, including circaundecennians) in the time structure of systolic (S) and diastolic (D) blood pressure (BP) and heart rate (HR). Because of the non-stationary nature in time and space of these and other physiologic and environmental periodic components that, like the wind, can appear and disappear in a given or other geographic location at one or another time, they have been called "Aeolian". The nonlinear estimation of the uncertainties of the periods (?s) of two or more variables being compared has been used to determine whether these components are congruent or not, depending on whether their CIs (95% confidence intervals) overlap or not. Among others, congruence has been found for components with ?s clustering around 10 years in us and around us. There is a selective assortment among individuals, variables and cycle characteristics (mean and circadian amplitude and acrophase). Apart from basic interest, like other nonphotic solar signatures such as transyears with periods slightly longer than one year or about 33-year Brückner-Egeson-Lockyer (BEL) cycles, about 10-year and longer cycles present in 7 of 7 self-monitoring individuals are of interest in the diagnosis of Vascular Variability Anomalies (VVAs), including MESOR-hypertension, and others. Some of the other VVAs, such as a circadian overswing, i.e., CHAT (Circadian Hyper-Aplitude-Tension), or an excessive pulse pressure, based on repeated 7-day around-the-clock records, can represent a risk of severe cardiovascular events, greater than that of a high BP. The differential diagnosis of physiologic cycles, infradians (components with a ? longer than 28 hours) as well as circadians awaits the collection of reference values for the infradian parameters of the cycles described herein. Just as in stroke-prone spontaneously hypertensive rats during the weeks after weaning CHAT precedes an elevation of the BP MESOR, a decadal overswing seems to precede the occurrence of high BP in two of the subjects here examined. Only around-the-clock monitoring in health for the collection of reference values will allow on their basis the differential diagnosis of the onsets of a circadian versus a circadecadal overswing in BP and the specification whether, and if so, when to initiate hypotensive non-drug or drug treatment. PMID:24860279

Halberg, Franz; Cornelissen, Germaine; Sothern, Robert B; Hillman, Dewayne; Watanabe, Yoshihiko; Haus, Erhard; Schwartzkopff, Othild; Best, William R

2012-01-01

116

Decadal Cycles in the Human Cardiovascular System  

PubMed Central

Seven of the eight authors of this report each performed physiologic self-surveillance, some around the clock for decades. We here document the presence of long cycles (decadals, including circaundecennians) in the time structure of systolic (S) and diastolic (D) blood pressure (BP) and heart rate (HR). Because of the non-stationary nature in time and space of these and other physiologic and environmental periodic components that, like the wind, can appear and disappear in a given or other geographic location at one or another time, they have been called “Aeolian”. The nonlinear estimation of the uncertainties of the periods (?s) of two or more variables being compared has been used to determine whether these components are congruent or not, depending on whether their CIs (95% confidence intervals) overlap or not. Among others, congruence has been found for components with ?s clustering around 10 years in us and around us. There is a selective assortment among individuals, variables and cycle characteristics (mean and circadian amplitude and acrophase). Apart from basic interest, like other nonphotic solar signatures such as transyears with periods slightly longer than one year or about 33-year Brückner-Egeson-Lockyer (BEL) cycles, about 10-year and longer cycles present in 7 of 7 self-monitoring individuals are of interest in the diagnosis of Vascular Variability Anomalies (VVAs), including MESOR-hypertension, and others. Some of the other VVAs, such as a circadian overswing, i.e., CHAT (Circadian Hyper-Aplitude-Tension), or an excessive pulse pressure, based on repeated 7-day around-the-clock records, can represent a risk of severe cardiovascular events, greater than that of a high BP. The differential diagnosis of physiologic cycles, infradians (components with a ? longer than 28 hours) as well as circadians awaits the collection of reference values for the infradian parameters of the cycles described herein. Just as in stroke-prone spontaneously hypertensive rats during the weeks after weaning CHAT precedes an elevation of the BP MESOR, a decadal overswing seems to precede the occurrence of high BP in two of the subjects here examined. Only around-the-clock monitoring in health for the collection of reference values will allow on their basis the differential diagnosis of the onsets of a circadian versus a circadecadal overswing in BP and the specification whether, and if so, when to initiate hypotensive non-drug or drug treatment. PMID:24860279

Halberg, Franz; Cornelissen, Germaine; Sothern, Robert B.; Hillman, Dewayne; Watanabe, Yoshihiko; Haus, Erhard; Schwartzkopff, Othild; Best, William R.

2013-01-01

117

Assessment of Cardiovascular Disease Risk Prediction Models: Evaluation Methods  

Microsoft Academic Search

\\u000a This paper uses a real world anaesthesia time-series monitoring data in the prediction of cardiovascular disease risk in a\\u000a manner similar to exercise electrocardiography. Models derived using the entire anaesthesia population and subgroups based\\u000a on pre-anaesthesia likelihood of complications are compared in an attempt to ascertain which model performance measures are\\u000a best suited to populations with differing pre-test probability of

Richi Nayak; Ellen Pitt

2011-01-01

118

Method of Propulsion of a Ferromagnetic Core in the Cardiovascular System Through Magnetic Gradients Generated by an MRI System  

Microsoft Academic Search

This paper reports the use of a magnetic resonance imaging (MRI) system to propel a ferromagnetic core. The con- cept was studied for future development of microdevices designed to perform minimally invasive interventions in remote sites acces- sible through the human cardiovascular system. A mathematical model is described taking into account various parameters such as the size of blood vessels,

Jean-Baptiste Mathieu; Gilles Beaudoin; Sylvain Martel

2006-01-01

119

Proteome analysis in cardiovascular pathophysiology using Dahl rat model.  

PubMed

Dahl salt-sensitive (DS) and salt-resistant (DR) inbred rat strains represent a well established animal model for cardiovascular research. Upon prolonged administration of high-salt-containing diet, DS rats develop systemic hypertension, and as a consequence they develop left ventricular hypertrophy, followed by heart failure. The aim of this work was to explore whether this animal model is suitable to identify biomarkers that characterize defined stages of cardiac pathophysiological conditions. The work had to be performed in two stages: in the first part proteomic differences that are attributable to the two separate rat lines (DS and DR) had to be established, and in the second part the process of development of heart failure due to feeding the rats with high-salt-containing diet has to be monitored. This work describes the results of the first stage, with the outcome of protein expression profiles of left ventricular tissues of DS and DR rats kept under low salt diet. Substantial extent of quantitative and qualitative expression differences between both strains of Dahl rats in heart tissue was detected. Using Principal Component Analysis, Linear Discriminant Analysis and other statistical means we have established sets of differentially expressed proteins, candidates for further molecular analysis of the heart failure mechanisms. PMID:21338724

Grussenmeyer, Thomas; Meili-Butz, Silvia; Roth, Volker; Dieterle, Thomas; Brink, Marijke; Winkler, Bernhard; Matt, Peter; Carrel, Thierry P; Eckstein, Friedrich S; Lefkovits, Ivan; Grapow, Martin T R

2011-05-01

120

REGULARIZED IMAGE RECONSTRUCTION FOR PS MODEL-BASED CARDIOVASCULAR MRI  

PubMed Central

Real-time cardiovascular MRI is a useful and challenging dynamic imaging application. The partial separability (PS) model enables reconstruction of dynamic cardiac images from highly undersampled (k, t)-space data. However, the underlying PS model-based reconstruction problem is ill-conditioned, so regularization is often necessary to stabilize its solution. It has been shown that ?1 regularization is useful for finding sparse solutions, and ?2 regularization is widely used to incorporate anatomical constraints. An important practical question is which regularization scheme to use for PS model-based cardiovascular imaging. We address this problem by implementing both schemes and evaluating their performances in terms of reconstruction error, image artifacts, image noise, computation time, and performance characterizability. The ?1-regularized results exhibit lower reconstruction error, artifact energy, and noise variance, while ?2 regularization is much faster and produces predictable reconstruction results. This study indicates that the ?1 scheme is preferable when image quality is the main concern. PMID:25283177

Christodoulou, Anthony G.; Zhao, Bo; Liang, Zhi-Pei

2012-01-01

121

Autonomic nervous system mediated effects of food intake : Interaction between gastrointestinal and cardiovascular systems  

Microsoft Academic Search

The studies presented in this thesis focused on the autonomic nervous system mediated interactions between the gastrointestinal and cardiovascular systems in response to food intake and on potential consequences of failure of these interactions. The effects of food intake on cardiovascular parameters, including muscle sympathetic nerve activity, were studied in healthy young and healthy elderly individuals, in patients who were

N. P. van Orshoven

2008-01-01

122

CaMKII in the Cardiovascular System: Sensing Redox States  

PubMed Central

The multifunctional Ca2+ and calmodulin-dependent protein kinase II (CaMKII) is now recognized to play a central role in pathological events in the cardiovascular system. CaMKII has diverse downstream targets that promote vascular disease, heart failure and arrhythmias, so improved understanding of CaMKII signaling has the potential to lead to new therapies for cardiovascular disease. CaMKII is a multimeric serine-threonine kinase that is initially activated by binding calcified calmodulin (Ca2+/CaM). Under conditions of sustained exposure to elevated Ca2+/CaM CaMKII transitions into a Ca2+/CaM-autonomous enzyme by two distinct but parallel processes. Autophosphorylation of threonine 287 in the CaMKII regulatory domain ‘traps’ CaMKII into an open configuration even after Ca2+/CaM unbinding. More recently, our group identified a pair of methionines (281/282) in the CaMKII regulatory domain that undergo a partially reversible oxidation which, like autophosphorylation, prevents CaMKII from inactivating after Ca2+/CaM unbinding. Here we review roles of CaMKII in cardiovascular disease with an eye to understanding how CaMKII may act as a transduction signal to connect pro-oxidant conditions into specific downstream pathological effects that are relevant to rare and common forms of cardiovascular disease. PMID:21742790

Erickson, Jeffrey R.; He, B. Julie; Grumbach, Isabella M.; Anderson, Mark E

2013-01-01

123

Cardiovascular Changes in Animal Models of Metabolic Syndrome  

PubMed Central

Metabolic syndrome has been defined as a group of risk factors that directly contribute to the development of cardiovascular disease and/or type 2 diabetes. Insulin resistance seems to have a fundamental role in the genesis of this syndrome. Over the past years to the present day, basic and translational research has used small animal models to explore the pathophysiology of metabolic syndrome and to develop novel therapies that might slow the progression of this prevalent condition. In this paper we discuss the animal models used for the study of metabolic syndrome, with particular focus on cardiovascular changes, since they are the main cause of death associated with the condition in humans. PMID:23691518

Lehnen, Alexandre M.; Rodrigues, Bruno; Irigoyen, Maria Cláudia; De Angelis, Kátia; Schaan, Beatriz D'Agord

2013-01-01

124

Human Induced Pluripotent Stem Cell Models of Inherited Cardiovascular Diseases.  

PubMed

Cardiovascular cells derived from patient specific induced Pluripotent Stem Cell (iPSC) harbor gene mutations associated with the pathogenesis of inherited cardiac diseases and congenital heart diseases (CHD). Numerous reports have demonstrated the utilization of human induced Pluripotent Stem Cell (hiPSC) to model cardiac diseases as a means of investigating their underlying mechanisms. So far, they have been shown to investigate the molecular mechanisms of many cardiac disorders, such as long-QT syndrome (LQT), catecholaminergic polymorphic ventricular tachycardia (CPVT), dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), LEOPARD syndrome (LS), arrhythmogenic cardiomyopathy (ACM), Friedreich ataxia (FRDA), Barth syndrome (BTHS), hypoplastic left heart syndrome (HLHS), Marfan syndrome (MFS) and other CHD. This article summarizes the growing body of research related to modeling various cardiac diseases using hiPSCs. Moreover, by reviewing the methods used in previous studies, we propose multiple novel applications of hiPSCs to investigate comprehensive cardiovascular disorders and facilitate drug discovery. PMID:25322695

Jiang, Wenjian; Lan, Feng; Zhang, Hongjia

2014-10-16

125

[Helical (spiral or swirling) blood flow in cardiovascular system].  

PubMed

In article covers theoretical preconditions for the hypothesis about helical (spiral or swirling) blood flow in cardiovascular system followed by its experimental corroboration. The role of the modern blood flow visualization methods--such as Color Doppler ultrasound and magnetic-resonance angiography--in registration and investigation of the regularities of the given phenomenon is described. The data describing the known parameters of helical blood flow--such as direction of the rotation and its quantitative parameters in large arteries--are given. The main hypotheses for flow screw mechanisms are considered from the point of view of cardiovascular system structural organization. Biological role of helical blood flow is discussed, in respect of which there are diametrically opposed points of view, which consider it as a physiological phenomenon on one side, and as a patogenetic factor of atherosclerosis development on the other. PMID:23789353

Kirsanov, R I; Kulikov, V P

2013-01-01

126

Clinical Application of Stem Cells in the Cardiovascular System  

Microsoft Academic Search

\\u000a Regenerative medicine encompasses “tissue engineering” – the in vitro fabrication of tissues and\\/or organs using scaffold\\u000a material and viable cells – and “cell therapy” – the transplantation or manipulation of cells in diseased tissue in vivo.\\u000a In the cardiovascular system, tissue engineering strategies are being pursued for the development of viable replacement blood\\u000a vessels, heart valves, patch material, cardiac pacemakers

Christof Stamm; Kristin Klose; Yeong-Hoon Choi

2010-01-01

127

Therapy Insight: cardiovascular disease in pediatric systemic lupus erythematosus  

Microsoft Academic Search

In 15–20% of cases, systemic lupus erythematosus (SLE) presents before the age of 18 years, and such early-onset SLE seems to be particularly severe. SLE is an independent risk factor for premature atherosclerosis and death in young, premenopausal women with SLE, even after controlling for traditional cardiovascular risk factors. Children and adolescents with SLE are particularly susceptible to this long-term

Stacy P Ardoin; Laura Schanberg; Christy Sandborg

2008-01-01

128

Rational macromodeling of 1D blood flow in the human cardiovascular system.  

PubMed

In this paper, we present a novel rational macromodeling approach for the description of 1D blood flow in the human cardiovascular system, which is suitable for time-domain simulations. Using the analogy of the blood flow propagation problem with transmission lines and considering the hypothesis of linearized Navier-Stokes equations, a frequency-domain rational macromodel for each arterial segment has been built. The poles and the residues of each arterial segment macromodel have been calculated by means of the Vector Fitting technique. Finally, the rational macromodel of the whole cardiovascular system is obtained by properly combining the macromodels of the single arterial segments using an interconnect matrix. The rational form of the proposed cardiovascular model leads to a state-space or electrical circuit model suitable for time-domain analysis. The stability and passivity properties of the global cardiovascular model are discussed to guarantee stable time-domain simulations. The proposed macromodeling approach has been validated by pertinent numerical results. Copyright © 2015?John Wiley & Sons, Ltd. PMID:25656004

Ferranti, Francesco; Tamburrelli, Vincenzopio; Antonini, Giulio

2015-03-01

129

competency Course Objective 1 1a Describe the pathophysiology of common and major diseases of the cardiovascular organ system.  

E-print Network

of common and major diseases of the cardiovascular organ system. 2 1a,1b Recognize abnormalities of these mechanisms produce important cardiovascular diseases. 3 1c Describe of the common cardiovascular disease, including behavioral, pharmacological, and interventional

Myers, Lawrence C.

130

Sex and the Cardiovascular System: The Intriguing Tale of How Women and Men Regulate Cardiovascular Function Differently  

NSDL National Science Digital Library

The ability to recognize and appreciate from a reproductive standpoint that males and females possess different attributes has been long standing. Only more recently have we begun to look more deeply into both the similarities and differences between men and women, as well as between boys and girls, with respect to the structure and function of other organ systems. This article focuses on the cardiovascular system, with examples of sex differences in the control of coronary function, blood pressure, and volume. Recognizing the differences between the sexes with respect to cardiovascular function facilitates understanding of the mechanisms whereby homeostasis can be achieved using different contributions or components of the living system. Furthermore, recognition of the differences as well as the similarities permits the design of appropriate diagnostic instruments, recognition of sex-specific pathophysiology, and implementation of appropriate treatment of cardiovascular disease in men and women.

PhD Virginia H. Huxley (University of Missouri School of Medicine Department of Medical Pharmacology and Physiology)

2007-03-01

131

Endocannabinoid system in cardiovascular disorders - new pharmacotherapeutic opportunities  

PubMed Central

The long history of Cannabis sativa had its development stimulated and oriented for medicine after the discovery and chemical characterization of its main active ingredient, the 9-tetrahydrocannabinol (9-THC). Consequently, a binding site for 9-THC was identified in rat brains and the first cannabinoid receptor (CB1) was cloned, followed by the CB2 and by the discover of two endogenous agonists: anandamide and 2-arachidonoyl glycerol. Cannabinoid receptors, endocannabinoids and the enzymes that catalyze its synthesis and degradation constitute the endocannabinoid system (ECS), which plays an important role in the cardiovascular system. In vivo experiments with rats have demonstrated the action of anandamide and 2-AG on the development of atherosclerotic plaque, as well as an effect on heart rate, blood pressure, vasoactivity and energy metabolism (action in dyslipidemia and obesity). Recent studies with an antagonist of CB1 receptors showed that the modulation of ECS can play an important role in reducing cardiovascular risk in obese and dyslipidemic patients. Similarly, studies in rats have demonstrated the action of CB2 receptors in adhesion, migration, proliferation and function of immune cells involved in the atherosclerotic plaque formation process. The evidence so far gathered shows that the modulation of ECS (as agonism or antagonism of its receptors) is an enormous potential field for research and intervention in multiple areas of human pathophysiology. The development of selective drugs for the CB1 and CB2 receptors may open a door to new therapeutic regimens.This review article aims to address the key findings and evidences on the modulation of ECS, in order to prospect future forms of therapeutic intervention at the cardiovascular level. A recent, emerging, controversial and of undoubted scientific interest subject, which states as a potential therapeutic target to reach in the 21st century. PMID:21966155

Cunha, Pedro; Romão, Ana M.; Mascarenhas-Melo, Filipa; Teixeira, Helena M.; Reis, Flávio

2011-01-01

132

Neuropeptide control of the cardiovascular system in fish and reptiles.  

PubMed

Accumulating evidence shows the involvement of neuropeptides in cardiovascular control in mammals as well as non-mammalian species. Our own immunohistochemical studies indicate a sparse innervation only in cyclostomes, holostean fish and lungfish, a more extensive variation and distribution in elasmobranchs and teleosts, and a rich and varied innervation of the cardiovascular system in crocodiles and lizards. Vasoactive intestinal polypeptide (VIP), neuropeptie Y (NPY), gastrin releasing peptide (GRP) and tachykinins are present in most vertebrate groups. VIP is vasodilatory in the Atlantic cod (Gadus morhua) as in most mammalian species, but increases gut vascular resistance in the spiny dogfish (Squalus acanthias). NPY potentiates the effect of noradrenaline on skate (Raja rhina) coronary vessels, suggesting an interaction between adrenergic mechanisms and NPY early in evolution, but studies in the spiny dogfish and the crocodile also demonstrate different mechanisms for the action of NPY and adrenaline in some species. Bombesin/GRP increases flow to the gut in the spiny dogfish by an increase in somatic vascular resistance, while visceral resistance remains unchanged. In the caiman (Caiman crocodylus crocodylus) bombesin causes a shunting of blood from the lung to the gut. Substance P and other tachykinins in general increase flow to the gut, and on some occasions also increase somatic blood flow. Flow in the anastomosis of the crocodile (Crocodylus porosus) gut is increased by substance P. The results presented here are a review of several published and unpublished studies. PMID:8728849

Holmgren, S

1995-01-01

133

Impact of atrial fibrillation on the cardiovascular system through a lumped-parameter approach.  

PubMed

Atrial fibrillation (AF) is the most common arrhythmia affecting millions of people in the Western countries and, due to the widespread impact on the population and its medical relevance, is largely investigated in both clinical and bioengineering sciences. However, some important feedback mechanisms are still not clearly established. The present study aims at understanding the global response of the cardiovascular system during paroxysmal AF through a lumped-parameter approach, which is here performed paying particular attention to the stochastic modeling of the irregular heartbeats and the reduced contractility of the heart. AF can be here analyzed by means of a wide number of hemodynamic parameters and avoiding the presence of other pathologies, which usually accompany AF. Reduced cardiac output with correlated drop of ejection fraction and decreased amount of energy converted to work by the heart during blood pumping, as well as higher left atrial volumes and pressures are some of the most representative results aligned with the existing clinical literature and here emerging during acute AF. The present modeling, providing new insights on cardiovascular variables which are difficult to measure and rarely reported in literature, turns out to be an efficient and powerful tool for a deeper comprehension and prediction of the arrythmia impact on the whole cardiovascular system. PMID:25192922

Scarsoglio, Stefania; Guala, Andrea; Camporeale, Carlo; Ridolfi, Luca

2014-11-01

134

A Large-Scale, Energetic Model of Cardiovascular Homeostasis Predicts Dynamics of Arterial Pressure in Humans  

PubMed Central

The energetic balance of forces in the cardiovascular system is vital to the stability of blood flow to all physiological systems in mammals. Yet, a large-scale, theoretical model, summarizing the energetic balance of major forces in a single, mathematically closed system has not been described. Although a number of computer simulations have been successfully performed with the use of analog models, the analysis of energetic balance of forces in such models is obscured by a big number of interacting elements. Hence, the goal of our study was to develop a theoretical model that represents large-scale, energetic balance in the cardiovascular system, including the energies of arterial pressure wave, blood flow, and the smooth muscle tone of arterial walls. Because the emphasis of our study was on tracking beat-to-beat changes in the balance of forces, we used a simplified representation of the blood pressure wave as a trapezoidal pressure-pulse with a strong-discontinuity leading front. This allowed significant reduction in the number of required parameters. Our approach has been validated using theoretical analysis, and its accuracy has been confirmed experimentally. The model predicted the dynamics of arterial pressure in human subjects undergoing physiological tests and provided insights into the relationships between arterial pressure and pressure wave velocity. PMID:18269976

Roytvarf, Alexander; Shusterman, Vladimir

2008-01-01

135

Resonances in the cardiovascular system caused by rhythmical muscle tension.  

PubMed

Paced 0.1 Hz breathing causes high-amplitude HR oscillation, triggering resonance in the cardiovascular system (CVS). This oscillation is considered to be a primary therapeutic factor in HRV biofeedback treatments. This study examined whether rhythmical skeletal muscle tension (RSMT) can also cause 0.1 Hz resonance in the CVS, and compared oscillatory reactivity in CVS functions caused by RSMT and paced breathing (PB). Sixteen young healthy participants completed five tasks: baseline, three RSMT tasks at frequencies of 0.05, 0.1, and 0.2 Hz, and a 0.1 Hz PB task. ECG, respiration, finger pulse, and skin conductance data were collected. Results showed that 0.1 Hz RSMT as well as 0.1 Hz PB triggered resonance in the CVS and caused equivalent oscillations in all measured CVS functions, although in women, RSMT compared to PB caused lower HR oscillation. Clinical application of 0.1 Hz RSMT is discussed. PMID:21143610

Vaschillo, Evgeny G; Vaschillo, Bronya; Pandina, Robert J; Bates, Marsha E

2011-07-01

136

Weighted hurdle regression method for joint modeling of cardiovascular events likelihood and rate in the US dialysis population.  

PubMed

We propose a new weighted hurdle regression method for modeling count data, with particular interest in modeling cardiovascular events in patients on dialysis. Cardiovascular disease remains one of the leading causes of hospitalization and death in this population. Our aim is to jointly model the relationship/association between covariates and (i) the probability of cardiovascular events, a binary process, and (ii) the rate of events once the realization is positive-when the 'hurdle' is crossed-using a zero-truncated Poisson distribution. When the observation period or follow-up time, from the start of dialysis, varies among individuals, the estimated probability of positive cardiovascular events during the study period will be biased. Furthermore, when the model contains covariates, then the estimated relationship between the covariates and the probability of cardiovascular events will also be biased. These challenges are addressed with the proposed weighted hurdle regression method. Estimation for the weighted hurdle regression model is a weighted likelihood approach, where standard maximum likelihood estimation can be utilized. The method is illustrated with data from the United States Renal Data System. Simulation studies show the ability of proposed method to successfully adjust for differential follow-up times and incorporate the effects of covariates in the weighting. PMID:24930810

Sentürk, Damla; Dalrymple, Lorien S; Mu, Yi; Nguyen, Danh V

2014-11-10

137

76 FR 62164 - VASRD Improvement Forum-Updating Disability Criteria for the Respiratory System, Cardiovascular...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Cardiovascular System, Hearing Impairment, and Ear, Nose and Throat Diseases AGENCY: Department...Cardiovascular System, Hearing Impairment, and Ear, Nose and Throat Diseases. The purpose...Acuity (38 CFR 4.85 and 4.86) and (4) Ear, Nose and Throat Diseases (38 CFR...

2011-10-06

138

National Training Course. Emergency Medical Technician. Paramedic. Instructor's Lesson Plans. Module VI. Cardiovascular System.  

ERIC Educational Resources Information Center

This instructor's lesson plan guide on the cardiovascular system is one of fifteen modules designed for use in the training of emergency medical technicians (paramedics). Seven units of study are presented: (1) the anatomy and physiology of the cardiovascular system; (2) patient assessment for the cardiac patient; (3) pathophysiology; (4) reading…

National Highway Traffic Safety Administration (DOT), Washington, DC.

139

Influence of physical fields of active geological faults on the human cardiovascular system  

NASA Astrophysics Data System (ADS)

Results of studying the human cardiovascular system within zones of Altai Mountain geological faults are presented. It is shown that features of the geological-geophysical characteristics have an effect on different control circuits of the human cardiovascular system and cause a change in its functioning.

Shitov, A. V.; Borodin, A. S.; Tuzhilkin, D. A.; Apryatkina, M. L.

2014-12-01

140

Modeling and Simulation Approaches for Cardiovascular Function and Their Role in Safety Assessment  

PubMed Central

Systems pharmacology modeling and pharmacokinetic-pharmacodynamic (PK/PD) analysis of drug-induced effects on cardiovascular (CV) function plays a crucial role in understanding the safety risk of new drugs. The aim of this review is to outline the current modeling and simulation (M&S) approaches to describe and translate drug-induced CV effects, with an emphasis on how this impacts drug safety assessment. Current limitations are highlighted and recommendations are made for future effort in this vital area of drug research.

Collins, TA; Bergenholm, L; Abdulla, T; Yates, JWT; Evans, N; Chappell, MJ; Mettetal, JT

2015-01-01

141

Neural Control of the Cardiovascular System in Space  

NASA Technical Reports Server (NTRS)

During the acute transition from lying supine to standing upright, a large volume of blood suddenly moves from the chest into the legs. To prevent fainting, the blood pressure control system senses this change immediately, and rapidly adjusts flow (by increasing heart rate) and resistance to flow (by constricting the blood vessels) to restore blood pressure and maintain brain blood flow. If this system is inadequate, the brain has a backup plan. Blood vessels in the brain can adjust their diameter to keep blood flow constant. If blood pressure drops, the brain blood vessels dilate; if blood pressure increases, the brain blood vessels constrict. This process, which is called autoregulation, allows the brain to maintain a steady stream of oxygen, even when blood pressure changes. We examined what changes in the blood pressure control system or cerebral autoregulation contribute to the blood pressure control problems seen after spaceflight. We asked: (1) does the adaptation to spaceflight cause an adaptation in the blood pressure control system that impairs the ability of the system to constrict blood vessels on return to Earth?; (2) if such a defect exists, could we pinpoint the neural pathways involved?; and (3) does cerebral autoregulation become abnormal during spaceflight, impairing the body s ability to maintain constant brain blood flow when standing upright on Earth? We stressed the blood pressure control system using lower body negative pressure, upright tilt, handgrip exercise, and cold stimulation of the hand. Standard cardiovascular parameters were measured along with sympathetic nerve activity (the nerve activity causing blood vessels to constrict) and brain blood flow. We confirmed that the primary cardiovascular effect of spaceflight was a postflight reduction in upright stroke volume (the amount of blood the heart pumps per beat). Heart rate increased appropriately for the reduction in stroke volume, thereby showing that changes in heart rate regulation alone cannot be responsible for orthostatic hypotension after spaceflight. All of the astronauts in our study had an increase in sympathetic nerve activity during upright tilting on Earth postflight. This increase was well calibrated for the reduction in stroke volume induced by the upright posture. The results obtained from stimulating the sympathetic nervous system using handgrip exercise or cold stress were also entirely normal during and after spaceflight. No astronaut had reduced cerebral blood flow during upright tilt, and cerebral autoregulation was normal or even enhanced inflight. These experiments show that the cardiovascular adaptation to spaceflight does not lead to a defect in the regulation of blood vessel constriction via sympathetic nerve activity. In addition, cerebral autoregulation is well-maintained. It is possible that despite the increased sympathetic nerve activity, blood vessels did not respond with a greater degree of constriction than occurred preflight, possibly uncovering a limit of vasoconstrictor reserve.

Levine, Benjamin D.; Pawelczyk, James A.; Zuckerman, Julie; Zhang, Rong; Fu, Qi; Iwasaki, Kenichi; Ray, Chet; Blomqvist, C. Gunnar; Lane, Lynda D.; Giller, Cole A.

2003-01-01

142

Embedding a cardiac pulsatile model into an integrated model of the cardiovascular regulation for heart failure followup  

PubMed Central

The analysis of follow-up data from patients suffering from heart failure is a difficult task, due to the complex and multifactorial nature of this pathology. In this paper, we present a coupled model, integrating a pulsatile heart into a model of the short to long-term regulations of the cardiovascular system. An interface method is proposed to couple these models, which present significantly different time scales. Results from a sensitivity analysis of the original and integrated models are proposed, with simulations reproducing the main effects of the short and long-term responses of an acute decompensated heart failure episode on a patient undergoing cardiac resynchronization therapy. PMID:21690004

Le Rolle, Virginie; Ojeda, David; Hernández, Alfredo I.

2011-01-01

143

Prediction and management of cardiovascular outcomes in systemic lupus erythematosus.  

PubMed

Atherosclerosis is the major cause of cardiovascular disease (CVD), which represents the major cause of death. During recent years, it has become clear that atherosclerosis is a chronic inflammatory condition where immunity could play an important role. Usually, it is when atherosclerotic plaques rupture that CVD follows, but some cases of CVD can occur without apparent atherosclerosis. In systemic lupus erythematosus, the risk of CVD is very high and the prevalence of atherosclerotic plaques, including vulnerable ones, is increased. A combination of traditional and non-traditional risk factors is implicated for the prediction of CVD in systemic lupus erythematosus. Traditional risk factors include hypertension, dyslipidemia, smoking and diabetes, though the exact importance of each of these in systemic lupus erythematosus is not clear. Anti-phospholipid antibodies, systemic inflammation and low levels of natural antibodies such as those against phosphorylcholine (anti-PC) are examples of non-traditional risk factors. Control of disease activity and disease manifestations and of established risk factors is important. PMID:25517760

Frostegård, Johan

2015-02-01

144

An integrative model of respiratory and cardiovascular control in sleep-disordered breathing  

PubMed Central

While many physiological control models exist in the literature, none thus far has focused on characterizing the interactions among the respiratory, cardiovascular and sleep-wake regulation systems that occur in sleep-disordered breathing. The model introduced in this study integrates the autonomic control of the cardiovascular system, chemoreflex and state-related control of respiration, including respiratory and upper airway mechanics, along with a model of circadian and sleep-wake regulation. The integrative model provides realistic predictions of the physiological responses under a variety of conditions including: the sleep-wake cycle, hypoxia-induced periodic breathing, Cheyne-Stokes respiration in chronic heart failure, and obstructive sleep apnoea (OSA). It can be used to investigate the effects of a variety of interventions, such as isocapnic and hypercapnic and/or hypoxic gas administration, the Valsalva and Mueller maneuvers, and the application of continuous positive airway pressure on OSA subjects. By being able to delineate the influences of the various interacting physiological mechanisms, the model is useful in providing a more lucid understanding of the complex dynamics that characterize state-cardiorespiratory control in the different forms of sleep-disordered breathing. PMID:20542148

Cheng, Limei; Ivanova, Olga; Fan, Hsing-Hua; Khoo, Michael C. K.

2010-01-01

145

A system identification approach to non-invasive central cardiovascular monitoring  

E-print Network

This thesis presents a new system identification approach to non-invasive central cardiovascular monitoring problem. For this objective, this thesis will develop and analyze blind system identification and input signal ...

Hahn, Jin-Oh, Ph. D. Massachusetts Institute of Technology

2008-01-01

146

Theory and developments in an unobtrusive cardiovascular system representation: ballistocardiography.  

PubMed

Due to recent technological improvements, namely in the field of piezoelectric sensors, ballistocardiography - an almost forgotten physiological measurement - is now being object of a renewed scientific interest.Transcending the initial purposes of its development, ballistocardiography has revealed itself to be a useful informative signal about the cardiovascular system status, since it is a non-intrusive technique which is able to assess the body's vibrations due to its cardiac, and respiratory physiological signatures.Apart from representing the outcome of the electrical stimulus to the myocardium - which may be obtained by electrocardiography - the ballistocardiograph has additional advantages, as it can be embedded in objects of common use, such as a bed or a chair. Moreover, it enables measurements without the presence of medical staff, factor which avoids the stress caused by medical examinations and reduces the patient's involuntary psychophysiological responses.Given these attributes, and the crescent number of systems developed in recent years, it is therefore pertinent to revise all the information available on the ballistocardiogram's physiological interpretation, its typical waveform information, its features and distortions, as well as the state of the art in device implementations. PMID:21673836

Pinheiro, Eduardo; Postolache, Octavian; Girão, Pedro

2010-01-01

147

A Simple Ballistocardiographic System for a Medical Cardiovascular Physiology Course  

NSDL National Science Digital Library

Ballistocardiography is an old, noninvasive technique used to record the movements of the body synchronous with the heartbeat due to left ventricular pump activity. Despite the fact that this technique to measure cardiac output has been superseded by more advanced and precise techniques, it is useful for teaching cardiac cycle physiology in an undergraduate practical course because of its noninvasive application in humans, clear physiological and physiopathological analysis, and practical approach to considering cardiac output issues. In the present report, a simple, low cost, easy-to-build ballistocardiography system is implemented together with a theoretical and practical session that includes NewtonÂ?s laws, cardiac output, cardiac pump activity, anatomy and physiology of the vessel circulation, vectorial composition, and signal transduction, which makes cardiovascular physiology easy to understand and focuses on the study of cardiac output otherwise seen only with the help of computer simulation or echocardiography. The proposed system is able to record body displacement or force as ballistocardiography traces and its changes caused by different physiological factors. The ballistocardiography session was included in our medical physiology course six years ago with very high acceptance and approval rates from the students.

Antonio Eblen-Zajjur (Universidad de Carabobo Departamento Ciencias Fisiológicas)

2003-12-01

148

Theory and Developments in an Unobtrusive Cardiovascular System Representation: Ballistocardiography  

PubMed Central

Due to recent technological improvements, namely in the field of piezoelectric sensors, ballistocardiography – an almost forgotten physiological measurement – is now being object of a renewed scientific interest. Transcending the initial purposes of its development, ballistocardiography has revealed itself to be a useful informative signal about the cardiovascular system status, since it is a non-intrusive technique which is able to assess the body’s vibrations due to its cardiac, and respiratory physiological signatures. Apart from representing the outcome of the electrical stimulus to the myocardium – which may be obtained by electrocardiography – the ballistocardiograph has additional advantages, as it can be embedded in objects of common use, such as a bed or a chair. Moreover, it enables measurements without the presence of medical staff, factor which avoids the stress caused by medical examinations and reduces the patient’s involuntary psychophysiological responses. Given these attributes, and the crescent number of systems developed in recent years, it is therefore pertinent to revise all the information available on the ballistocardiogram’s physiological interpretation, its typical waveform information, its features and distortions, as well as the state of the art in device implementations. PMID:21673836

Pinheiro, Eduardo; Postolache, Octavian; Girão, Pedro

2010-01-01

149

Computational models of cardiovascular response to orthostatic stress  

E-print Network

The cardiovascular response to changes in posture has been the focus of numerous investigations in the past. Yet despite considerable, targeted experimental effort, the mechanisms underlying orthostatic intolerance (OI) ...

Heldt, Thomas, 1972-

2004-01-01

150

A Novel Model of Cardiovascular Risk Based on Kidney Function  

Microsoft Academic Search

Background\\/Aims: Although creatinine-based estimated glomerular filtration rate (eGFR) is associated with cardiovascular events, threshold values for optimum discrimination are unclear. We aimed to identify serum creatinine and eGFR thresholds of maximum sensitivity and specificity (MaxSn+Sp) for a composite outcome of coronary heart disease, stroke, and death. Methods: Classification tree methodology defined the hierarchical rank of serum creatinine, eGFR, and cardiovascular

Robert N. Foley; Allan J. Collins

2011-01-01

151

Protective effects of AMP-activated protein kinase in the cardiovascular system  

PubMed Central

Abstract Cardiovascular diseases remain the leading cause of mortality worldwide. Recent studies of AMP-activated protein kinase (AMPK), a highly conserved sensor of cellular energy status, suggest that there might be therapeutic value in targeting the AMPK signaling pathway. AMPK is found in most mammalian tissues, including those of the cardiovascular system. As cardiovascular diseases are typically associated with blood flow occlusion and blood occlusion may induce rapid energy deficit, AMPK activation may occur during the early phase upon nutrient deprivation in cardiovascular organs. Therefore, investigation of AMPK in cardiovascular organs may help us to understand the pathophysiology of defence mechanisms in these organs. Recent studies have provided proof of concept for the idea that AMPK is protective in heart as well as in vascular endothelial and smooth muscle cells. Moreover, dysfunction of the AMPK signalling pathway is involved in the genesis and development of various cardiovascular diseases, including atherosclerosis, hypertension and stroke. The roles of AMPK in the cardiovascular system, as they are currently understood, will be presented in this review. The interaction between AMPK and other cardiovascular signalling pathways such as nitric oxide signalling is also discussed. PMID:20874722

Xu, Qiang; Si, Liang-Yi

2010-01-01

152

Introduction: Cardiovascular physics  

NASA Astrophysics Data System (ADS)

The number of patients suffering from cardiovascular diseases increases unproportionally high with the increase of the human population and aging, leading to very high expenses in the public health system. Therefore, the challenge of cardiovascular physics is to develop high-sophisticated methods which are able to, on the one hand, supplement and replace expensive medical devices and, on the other hand, improve the medical diagnostics with decreasing the patient's risk. Cardiovascular physics-which interconnects medicine, physics, biology, engineering, and mathematics-is based on interdisciplinary collaboration of specialists from the above scientific fields and attempts to gain deeper insights into pathophysiology and treatment options. This paper summarizes advances in cardiovascular physics with emphasis on a workshop held in Bad Honnef, Germany, in May 2005. The meeting attracted an interdisciplinary audience and led to a number of papers covering the main research fields of cardiovascular physics, including data analysis, modeling, and medical application. The variety of problems addressed by this issue underlines the complexity of the cardiovascular system. It could be demonstrated in this Focus Issue, that data analyses and modeling methods from cardiovascular physics have the ability to lead to significant improvements in different medical fields. Consequently, this Focus Issue of Chaos is a status report that may invite all interested readers to join the community and find competent discussion and cooperation partners.

Wessel, Niels; Kurths, Jürgen; Ditto, William; Bauernschmitt, Robert

2007-03-01

153

How did Haly Abbas look at the cardiovascular system?  

PubMed

Persian scholars, especially those who lived during the Golden Age of Islamic Medicine (9th-12th century AD), made significant contributions to the healing arts and secured a place of honor for themselves in the history of this science. Ab? l-?asan Al? ibn al-'Abb?s al-Maj?s? Ahvazi (? 930-994AD), with the Latinized name of Haly Abbas, was a scientist from this part of the world who contributed to the advancement of medicine. He is the author of K?mil al-Sin?'ah al-Tibb?yah (The Perfect Book of the Art of Medicine), also commonly known as al-Kit?b al-Malik? (The Royal Book), a medical encyclopedia renowned for its systematic and precise content. This textbook covers a wide variety of medical issues, among them topics related to the science of cardiology. This paper reviews the main points of Haly Abbas' knowledge of the cardiovascular system, of which little has been written until now. PMID:24452226

Dalfardi, Behnam; Mahmoudi Nezhad, Golnoush Sadat; Mehdizadeh, Alireza

2014-03-01

154

Vasopressin and Oxytocin in Control of the Cardiovascular System  

PubMed Central

Vasopressin (VP) and oxytocin (OT) are mainly synthesized in the magnocellular neurons of the paraventricular (PVN) and supraoptic nucleus (SON) of the hypothalamus. Axons from the magnocellular part of the PVN and SON project to neurohypophysis where VP and OT are released in blood to act like hormones. Axons from the parvocellular part of PVN project to extra-hypothalamic brain areas (median eminence, limbic system, brainstem and spinal cord) where VP and OT act like neurotransmitters/modulators. VP and OT act in complementary manner in cardiovascular control, both as hormones and neurotransmitters. While VP conserves water and increases circulating blood volume, OT eliminates sodium. Hyperactivity of VP neurons and quiescence of OT neurons in PVN underlie osmotic adjustment to pregnancy. In most vascular beds VP is a potent vasoconstrictor, more potent than OT, except in the umbilical artery at term. The vasoconstriction by VP and OT is mediated via V1aR. In some vascular beds, i.e. the lungs and the brain, VP and OT produce NO dependent vasodilatation. Peripherally, VP has been found to enhance the sensitivity of the baro-receptor while centrally, VP and OT increase sympathetic outflow, suppresse baro-receptor reflex and enhance respiration. Whilst VP is an important mediator of stress that triggers ACTH release, OT exhibits anti-stress properties. Moreover, VP has been found to contribute considerably to progression of hypertension and heart failure while OT has been found to decrease blood pressure and promote cardiac healing. PMID:23997756

Japundži?-Žigon, Nina

2013-01-01

155

Hyperhomocysteinemia: a biochemical link between bone and cardiovascular system diseases?  

PubMed

Homocysteine (HCY) is a sulfur-containing amino acid involved in two metabolic pathways, catalized by cystathionine-B-synthase and methionine synthase, depending on vitamin (vit) B6, B12, and folate levels and enzymatic activity of methylenetetrahydrofolate. High HCY levels (HHCY) are associated with cardiovascular (CV) and bone diseases, in particular osteoporosis (OP)/hip fracture. As regards the mechanisms involved in the link between HHCY, CV diseases (CVD), and OP, it has been proposed the role of lysyl-oxydase inhibition that might interfere with collagen crosslink formation. Some studies suggested the dysregulation of the osteoprotegerin/receptor activator of nuclear factor-kappaB (RANK) ligand/RANK axis, others the involvement of oxidative stress. These mechanisms may act both on bone and CV system, but whether the common denominator is HCY itself or HCY is merely a marker, remains to be clearly established. Folate, vit B6, and B12 supplementation is associated with HCY reduction, but is unable to certainly reduce the incidence of OP/fracture and CVD, probably because, in the majority of patients, HCY is only moderately increased. PMID:19724160

Petramala, L; Acca, M; Francucci, C M; D'Erasmo, E

2009-01-01

156

A Prediction System for Cardiovascularity Diseases Using Genetic Fuzzy Rule-Based Systems  

Microsoft Academic Search

In this paper we present a fuzzy rule-based system to predict cardiovascularity diseases. The input variables of the system\\u000a are the most in ffuent factors for that type of diseases and the output is a risk prediction of suffering from them. Our objective\\u000a is to get an accurate prediction value and a system description with a high degree of interpretability.

Oscar Cordón; Francisco Herrera; J. De La Montaña; A. M. Sánchez; Pedro Villar

2002-01-01

157

Feasability of a ARFI/B-mode/Doppler system for real-time, freehand scanning of the cardiovascular system  

NASA Astrophysics Data System (ADS)

Acoustic radiation force impulse (ARFI) imaging has been previously described for the visualization of the cardiovascular system, including assessment of cerebral and lower-limb vascular disease, myocardial function, and cardiac RF ablation monitoring. Given that plaque imposes a 3-dimensional burden on the artery and that accurate visualization of all lesion borders are important for ablation guidance, it would be convenient if an entire plaque or lesion volume could be acquired, either using a 3D system or 2D freehand scanning. Currently, ARFI imaging uses single-frame acquisition, with acquisition times ranging from 100-200ms. Such a system would be cumbersome for real-time, freehand scanning. In this work, we evaluate the feasibility of using ARFI for freehand, real-time scanning of the cardiovascular system. New techniques are presented which acquire B-mode / ARFI/ and Color-flow Doppler (BACD) information in less than 50 ms. Freehand feasibility is evaluated by sweeping the BACD system across lesion phantoms and vascular phantoms modeling a thin-cap fibroatheroma at sweep rates currently utilized in conventional B-mode systems. Stationary in vivo BACD images were then formed from the carotid artery of a canine model, demonstrating the system's potential. The results suggest that little loss in either ARFI or Doppler quality occurs during translational-stage controlled, quasi-freehand sweeps.

Dumont, Douglas M.; Lee, Seung-Yun; Doherty, Joshua R.; Trahey, Gregg E.

2011-03-01

158

Pulmonary Complications Resulting from Genetic Cardiovascular Disease in Two Rat Models  

EPA Science Inventory

Underlying cardiovascular disease (CVD) has been considered a risk factor for exacerbation of air pollution health effects. Therefore, rodent models of CVD are increasingly used to examine mechanisms of variation in susceptibility. Pulmonary complications and altered iron homeost...

159

Pulmonary oxidative stress, inflammation and dysregulated iron homeostatis in rat models of cardiovascular disease  

EPA Science Inventory

Underlying cardiovascular disease (CVD) is considered a risk factor for the exacerbation of air pollution health effects. Therefore, rodent models of CVD are increasingly used to examine mechanisms ofvariation in susceptibility. Pulmonary oxidative stress, inflammation and altere...

160

Thioredoxin in the Cardiovascular System—Towards a Thioredoxin-Based Antioxidative Therapy  

Microsoft Academic Search

\\u000a Oxidative stress results from an imbalance between the production of reactive oxygen species (ROS) and the endogenous antioxidant\\u000a systems, which detoxify the reactive intermediates. Diseases of the cardiovascular system, including atherosclerosis, diabetes,\\u000a cardiac hypertrophy, and congestive heart disease are characterized by enhanced production of ROS. In these conditions ROS\\u000a promote cardiovascular pathology in part by activating inflammatory signaling pathways. One

Bradford C. Berk

161

[Psychosocial factors as predictors of atherosclerosis and cardiovascular events: contribution from animal models].  

PubMed

Conventional risk factors (abnormal lipids, hypertension, etc.) are independent predictors of atherosclerosis and cardiovascular events; however, these factors are not specific since about half patients with acute myocardial infarction paradoxically result at low cardiovascular risk. Recent prospective studies provide convincing evidence that some psychosocial factors are independent predictors of atherosclerosis and cardiovascular events, as well. Psychosocial factors that promote atherosclerosis can be divided into two general categories: chronic stressors, including social isolation/low social support and work stress (subordination without job control) and emotional factors, including affective disorders such as depression, severe anxiety and hostility/anger. The emotional factors, such as the chronic stressors, activate the biological mechanisms of chronic stress: increased activity of the hypothalamic-pituitary-adrenal axis, sympathetic system and inflammation processes, which have atherogenic effects, and an increase in blood coagulation. In spite of the amount of published data, psychosocial factors receive little attention in the medical setting. About 30 years ago, Kuller defined the criteria for a causal relation between a risk factor and atherosclerosis and cardiac events. The first of these criteria states that experimental research should demonstrate that any new factor would increase the extent of atherosclerosis or its complications in suitable animal models. We carried out a bibliographic research in order to investigate whether the results of the studies dealing with animal examination and experimentation support the psychosocial factors as predictors of atherosclerosis. Contributions related to some of the psychosocial factors such as social isolation, subordination and hostility/anger have been found. In these studies atherosclerotic extension has been evaluated at necroscopy; however, the incidence of cardiovascular events has not been investigated. As regards the biological mechanisms of chronic stress, the hypothalamic-pituitary-adrenal axis and the sympathetic system have been investigated. The studies have mainly been carried out on primates, and, to a less extent, on other mammals such as rabbit and wolf and on some species of birds. In the animals under social isolation, subordination or hostility/anger, a significantly more severe atherosclerosis was present, besides an increased activity of the hypothalamic-pituitary-adrenal axis and sympathetic system. In conclusion, the results offered by animal models seem to satisfy the first of Kuller's criteria, as for the three above-mentioned psychosocial factors. PMID:17216916

Alboni, Paolo; Alboni, Marco

2006-11-01

162

Modeling Cardiovascular Anatomy from Patient-Specific Imaging  

NASA Astrophysics Data System (ADS)

The importance of modern imaging techniques for capturing detailed structural information of a biological system cannot be understated. Unfortunately images do not reveal the "full functional story" and a spatially realistic computer model is often necessary for a comprehensive understanding of the complicated structural and physiological properties of the biological system's entities under investigation [1]. Deeper insights into structure-to-function relationships of different entities is achieved via finite element simulations of the modeled biomedical process. A 3D (three dimensional) finite element meshed computer model of the biological system is therefore a first step to perform such simulations.

Bajaj, Chandrajit; Goswami, Samrat

163

AptaCDSS-E: A classifier ensemble-based clinical decision support system for cardiovascular disease level prediction  

E-print Network

AptaCDSS-E: A classifier ensemble-based clinical decision support system for cardiovascular disease); Cardiovascular disease; Classifier ensemble; Support vector machines; Neural networks; Decision trees; Bayesian that cardiovascular disease (CVD), which includes heart disease and stroke, is one of the lead- ing causes of death

164

Site specific gene delivery in the cardiovascular system  

Microsoft Academic Search

Gene therapy holds great promise for treating both genetic and acquired disorders. However, progress toward effective human gene therapy has been thwarted by a number of problems including vector toxicity, poor targeting of diseased tissues, and host immune and inflammatory activity to name but a few of the challenges. Gene therapy for cardiovascular disease has been the subject of many

Ilia Fishbein; Stanley J. Stachelek; Jeanne M. Connolly; Robert L. Wilensky; Ivan Alferiev; Robert J. Levy

2005-01-01

165

Applicability of implantable telemetry systems in cardiovascular research.  

NASA Technical Reports Server (NTRS)

This paper briefly describes the results of an experimental program undertaken to develop and apply implanted telemetry to cardiovascular research. Because of the role the kidney may play in essential hypertension, emphasis is placed on telemetry's applicability in the study of renal physiology. Consequently, the relationship between pressure, flow, and hydraulic impedance are stressed. Results of an exercise study are given.

Krutz, R. W.; Rader, R. D.; Meehan, J. P.; Henry, J. P.

1971-01-01

166

An in vitro arterial model for testing cardiovascular drugs  

Microsoft Academic Search

Cardiovascular drug-eluting stents (DESs) have been used to prevent restenosis occurring after the implantation of bare metal stents (BMSs). Recent studies, however, have indicated that DESs can result in late in-stent thrombosis (LST) with a probability comparable to that of BMSs. LST can be best prevented by promoting endothelial cell (EC) growth in the stented region. One way of achieving

Somali Chaterji

2009-01-01

167

Choosing the Right Cardiovascular Delivery Model for Your Hospital: \\  

Microsoft Academic Search

Cardiovascular (CV) services garner significant attention in healthcare these days, and for good reason. Just look at the financial statements for the average American hospital. Our experience indicates that CV services account for 30-40% of revenue and can be as much as a whopping 60-70% of profit (net income). Add to that the projected population growth rate for the prime

Oliver Wendell Holmes

168

A common data model to assess cardiovascular hospitalization and mortality in atrial fibrillation patients using administrative claims and medical records  

PubMed Central

Purpose Atrial fibrillation/flutter (AF) is frequently associated with cardiovascular comorbidities. Observational health care databases are commonly used for research purposes in studies of quality of care, health economics, outcomes research, drug safety, and epidemiology. This retrospective cohort study applied a common data model to administrative claims data (Truven Health Analytics MarketScan® claims databases [MS-Claims]) and electronic medical records data (Geisinger Health System’s MedMining electronic medical record database [MG-EMR]) to examine the risk of cardiovascular hospitalization and all-cause mortality in relation to clinical risk factors in recent-onset AF and to assess the consistency of analyses for each data source. Methods Cohorts of patients with newly diagnosed AF (n=105,262 [MS-Claims] and n=3,919 [MG-EMR]) and demographically similar patients without AF (n=105,262 [MS-Claims] and n=3,872 [MG-EMR]) were followed from the qualifying AF diagnosis until cardiovascular hospitalization, death, database disenrollment, or study completion. A common data model standardized the data in structure, format, content, and nomenclature to allow for systematic assessment and comparison of outcomes from two disparate data sets. Results In both databases, AF patients had greater overall baseline comorbidity and higher incidence rates of cardiovascular hospitalization (threefold higher) and all-cause mortality (46% higher) than non-AF patients. For AF patients, incidence rates of cardiovascular hospitalization and all-cause mortality were increased by the concomitant presence of coronary disease, chronic obstructive pulmonary disease, and stroke at baseline. Overall, the pattern of cardiovascular hospitalization in the MS-Claims database was similar to that in the MG-EMR database. Compared with the MS-Claims database, the use of cardiovascular medications and the capture of certain comorbidities among AF patients appeared to be higher in the MG-EMR data set. Conclusion Similar standardized analyses across EMR and Claims databases were consistent in the association of AF with acute morbidity and an increased risk of all-cause mortality. Areas of inconsistency were due to differences in underlying population demographics and cardiovascular risks and completeness of certain data fields. PMID:25624771

Panaccio, Mary P; Cummins, Gordon; Wentworth, Charles; Lanes, Stephan; Reynolds, Shannon L; Reynolds, Matthew W; Miao, Raymond; Koren, Andrew

2015-01-01

169

[Adverse effects of ultrafine particles on the cardiovascular system and its mechanisms].  

PubMed

Cardiovascular disease is one of the major threats to human. Air pollution, which , as it become a problem too serious to be ignored in China, is known to be an important risk factor for cardiovascular disease. Among all pollutants, ultrafine particles ( UFPs) , defined as particles with their diameter less than 0. 1 f.Lm, are a specific composition. They are very small in size, large in quantity and surface area, and most important, capable of passing through the air-blood barrier. These unique features of UFPs make them special in their impact on cardiovascular system. Nowadays, the influence of UFPs on the cardiovascular system has become a hot topic. On the one side, studies have shown that UFPs can cause inflammation and oxidative stress in the lung, and then induce systemic inflammation by releasing cytokine and reactive oxygen species into the circulation. On the other side, UFPs themselves can "spillout"into the circulation and interact with their targets. By this way, UFPs directly affect endothelial cells, myocardial cells and the autonomic nervous system, which ultimately result in increased cardiovascular events. We intend to make an overview about the recent progress about the influence of UFPs on human cardiovascular disease and the related mechanisms, and argue for more attention to this issue. PMID:25651605

Yi, Tie-ci; Li, Jian-ping

2014-12-18

170

Modeling effects of age and sex on cardiovascular variability responses to aerobic ergometer exercise  

Microsoft Academic Search

After collecting data on the cardiovascular responses to ramp-type exercise tests on a cycle ergometer from 194 healthy male\\u000a and female subjects aged from 20 to 69 years, we constructed a mathematical model that simulates typical patterns of the cardiovascular\\u000a variability responses to ramp-type exercise loads below the anaerobic threshold. This was done by reflecting the following\\u000a physiological mechanisms: (1) suppression

Kohzoh Yoshino; Kimihiro Adachi; Keiko Ihochi; Katsunori Matsuoka

2007-01-01

171

The renin-angiotensin system and its blockade in diabetic renal and cardiovascular disease  

Microsoft Academic Search

Diabetic nephropathy, the most common cause of end-stage renal disease in the United States, is also associated with increased\\u000a cardiovascular mortality. The renin-angiotensin-aldosterone system (RAAS) plays a central role in the development and progression\\u000a of kidney disease and cardiovascular disease. Randomized, controlled trials have demonstrated renoprotection with the use\\u000a of angiotensin receptor blockers (ARBs) in type 2 and angiotensin-converting enzyme

Kambiz Kalantarinia; Mark D. Okusa

2006-01-01

172

Cardiovascular Disease Risk Models and Longitudinal Changes in Cognition: A Systematic Review  

PubMed Central

Background Cardiovascular disease and its risk factors have consistently been associated with poor cognitive function and incident dementia. Whether cardiovascular disease prediction models, developed to predict an individual's risk of future cardiovascular disease or stroke, are also informative for predicting risk of cognitive decline and dementia is not known. Objective The objective of this systematic review was to compare cohort studies examining the association between cardiovascular disease risk models and longitudinal changes in cognitive function or risk of incident cognitive impairment or dementia. Materials and Methods Medline, PsychINFO, and Embase were searched from inception to March 28, 2014. From 3,413 records initially screened, 21 were included. Results The association between numerous different cardiovascular disease risk models and cognitive outcomes has been tested, including Framingham and non-Framingham risk models. Five studies examined dementia as an outcome; fourteen studies examined cognitive decline or incident cognitive impairment as an outcome; and two studies examined both dementia and cognitive changes as outcomes. In all studies, higher cardiovascular disease risk scores were associated with cognitive changes or risk of dementia. Only four studies reported model prognostic performance indices, such as Area Under the Curve (AUC), for predicting incident dementia or cognitive impairment and these studies all examined non-Framingham Risk models (AUC range: 0.74 to 0.78). Conclusions Cardiovascular risk prediction models are associated with cognitive changes over time and risk of dementia. Such models are easily obtainable in clinical and research settings and may be useful for identifying individuals at high risk of future cognitive decline and dementia. PMID:25478916

Harrison, Stephanie L.; Ding, Jie; Tang, Eugene Y. H.; Siervo, Mario; Robinson, Louise; Jagger, Carol; Stephan, Blossom C. M.

2014-01-01

173

The effects of music on the cardiovascular system and cardiovascular health.  

PubMed

Music may not only improve quality of life but may also effect changes in heart rate and heart rate variability. It has been shown that cerebral flow was significantly lower when listening to 'Va pensiero' from Verdi's 'Nabucco' (70.4±3.3 cm/s) compared with 'Libiam nei lieti calici' from Verdi's 'La Traviata' (70.2±3.1 cm/s) (p<0.02) or Bach's Cantata No. 169 'Gott soll allein mein Herze haben' (70.9±2.9 cm/s) (p<0.02). There was no significant difference in cerebral flow during rest (67.6±3.3 cm/s) or when listening to Beethoven's Ninth Symphony (69.4±3.1 cm/s). It was reported that relaxing music significantly decreases the level of anxiety of patients in a preoperative setting (State-Trait Anxiety Inventory (STAI)-X-1 score 34)-to a greater extent even than orally administered midazolam (STAI-X-1 score 36) (p<0.001). In addition the score was better after surgery in the music group (STAI-X-1 score 30) compared with the midazolam group (STAI-X-1 score 34) (p<0.001). Higher effectiveness and absence of apparent adverse effects make relaxing, preoperative music a useful alternative to midazolam for premedication. In addition, there is sufficient practical evidence of stress reduction suggesting that a proposed regimen of listening to music while resting in bed after open-heart surgery is important in clinical use. After 30 min of bed rest, there was a significant difference in cortisol levels between the music (484.4 mmol/l) and the non-music group (618.8 mmol/l) (p<0.02). Vocal and orchestral music produce significantly better correlations between cardiovascular or respiratory signals compared with music with a more uniform emphasis (p<0.05). The greatest benefit on health is visible with classical music and meditation music, whereas heavy metal music or techno are not only ineffective but possibly dangerous and can lead to stress and/or life-threatening arrhythmias. The music of many composers most effectively improves quality of life, will increase health and probably prolong life, particularly music by Bach, Mozart or Italian composers. PMID:21062776

Trappe, Hans-Joachim

2010-12-01

174

Autonomic Nervous System Dysfunction and Inflammation Contribute to the Increased Cardiovascular Mortality Risk Associated With Depression  

PubMed Central

Objective To investigate prospectively whether autonomic nervous system (ANS) dysfunction and inflammation play a role in the increased cardiovascular disease (CVD)-related mortality risk associated with depression. Methods Participants in the Cardiovascular Health Study (n = 907; mean age, 71.3 ± 4.6 years; 59.1% women) were evaluated for ANS indices derived from heart rate variability (HRV) analysis (frequency and time domain HRV, and nonlinear indices, including detrended fluctuation analysis (DFA1) and heart rate turbulence). Inflammation markers included C-reactive protein, interleukin-6, fibrinogen, and white blood cell count). Depressive symptoms were assessed, using the 10-item Centers for Epidemiological Studies Depression scale. Cox proportional hazards models were used to investigate the mortality risk associated with depression, ANS, and inflammation markers, adjusting for demographic and clinical covariates. Results Depression was associated with ANS dysfunction (DFA1, p = .018), and increased inflammation markers (white blood cell count, p = .012, fibrinogen p = .043) adjusting for covariates. CVD-related mortality occurred in 121 participants during a median follow-up of 13.3 years. Depression was associated with an increased CVD mortality risk (hazard ratio, 1.88; 95% confidence interval, 1.23–2.86). Multivariable analyses showed that depression was an independent predictor of CVD mortality (hazard ratio, 1.72; 95% confidence interval, 1.05–2.83) when adjusting for independent HRV and inflammation predictors (DFA1, heart rate turbulence, interleukin-6), attenuating the depression-CVD mortality association by 12.7% (p < .001). Conclusion Autonomic dysfunction and inflammation contribute to the increased cardiovascular mortality risk associated with depression, but a large portion of the predictive value of depression remains unexplained by these neuroimmunological measures. PMID:20639389

Kop, Willem J.; Stein, Phyllis K.; Tracy, Russell P.; Barzilay, Joshua I.; Schulz, Richard; Gottdiener, John S.

2011-01-01

175

Part 2: The cardiovascular system and congenital heart disease.  

PubMed

Midwives are increasingly performing the examination of the newborn. In the second of a four-part series, this article considers the importance of the cardiovascular examination in the screening process. The significance of history taking, knowledge of risk factors and auscultation of the heart will be explored. The necessity for early detection and treatment of congenital cardiac abnormalities, along with the prerequisite referral pathways that the Newborn infant physical examination (NIPE) requires will also be highlighted. PMID:24600830

Carr, Natasha; Foster, Paula

2014-02-01

176

Physiology and pathology of the cardiovascular system: A physical perspective  

Microsoft Academic Search

\\u000a The purpose of this chapter is to introduce the reader to cardiovascular physiology and pathology. These are vast, complex\\u000a subjects, each filling large tomes and severely exercising the memory of medical students. By necessity, this will be a very\\u000a brief and, in places, simplistic introduction to the subject. Despite its simplicity, it can be very daunting to the newcomer\\u000a who

Marc Thiriet; Kim H. Parker

177

The P-glycoprotein transport system and cardiovascular drugs.  

PubMed

Permeability glycoprotein (P-gp) mediates the export of drugs from cells located in the small intestine, blood-brain barrier, hepatocytes, and kidney proximal tubule, serving a protective function for the body against foreign substances. Intestinal absorption, biliary excretion, and urinary excretion of P-gp substrates can therefore be altered by either the inhibition or induction of P-gp. A wide spectrum of drugs, such as anticancer agents and steroids, are known P-gp substrates and/or inhibitors, and many cardiovascular drugs have recently been observed to have clinically relevant interactions as well. We review the interactions among commonly prescribed cardiovascular drugs that are P-gp substrates and observe interactions involving P-gp that may be relevant to clinical practice. Cardiovascular drugs with narrow therapeutic indexes (e.g., antiarrhythmic agents, anticoagulant agents) have demonstrated large increases in concentrations when coadministered with potent P-gp inhibitors, thus increasing the risk for drug toxicity. Therefore, dose adjustment or use of alternative agents should be considered when strong P-gp-mediated drug-drug interactions are present. Finally, interactions between novel drugs and known P-gp inhibitors are now being systematically evaluated during drug development, and recommended guidelines for the administration of P-gp substrate drugs will be expanded. PMID:23563132

Wessler, Jeffrey D; Grip, Laura T; Mendell, Jeanne; Giugliano, Robert P

2013-06-25

178

Advantages of renin-angiotensin system blockade in the treatment of cardiovascular diseases.  

PubMed

The renin angiotensin system (RAS) plays a key role in the regulation of cardiovascular function, with angiotensin II being involved in hemodynamic and non-hemodynamic mechanism in the pathophysiology of cardiovascular disease. A number of studies demonstrated that pharamacological modulation of the RAS, either with angiotensin converting (ACE) inhibitor or an angiotensin II receptor blocker (ARB), provides cardiovascular and renal protection. Blockade of the RAS, either with ACE inhibitors or ARBs, decreases cardiovascular morbidity and mortality in high risk patients. ACE inhibitors as well as ARBs are drugs of choice in congestive heart failure, as well as in diabetic nephropathy. Especially, the combined RAS blockade with ACE inhibitors and ARBs was more effective than monotherapy in diabetic or non-diabetic nephropathy with proteinuria. However, this combined RAS blockade was not equally dominant in treatment of hypertension and was not recommended for widespread antihypertensive use. PMID:21287956

Gerc, Vjekoslav; Buksa, Marko

2010-01-01

179

Nprl3 is required for normal development of the cardiovascular system.  

PubMed

C16orf35 is a conserved and widely expressed gene lying adjacent to the human ?-globin cluster in all vertebrate species. In-depth sequence analysis shows that C16orf35 (now called NPRL3) is an orthologue of the yeast gene Npr3 (nitrogen permease regulator 3) and, furthermore, is a paralogue of its protein partner Npr2. The yeast Npr2/3 dimeric protein complex senses amino acid starvation and appropriately adjusts cell metabolism via the TOR pathway. Here we have analysed a mouse model in which expression of Nprl3 has been abolished using homologous recombination. The predominant effect on RNA expression appears to involve genes that regulate protein synthesis and cell cycle, consistent with perturbation of the mTOR pathway. Embryos homozygous for this mutation die towards the end of gestation with a range of cardiovascular defects, including outflow tract abnormalities and ventriculoseptal defects consistent with previous observations, showing that perturbation of the mTOR pathway may affect development of the myocardium. NPRL3 is a candidate gene for harbouring mutations in individuals with developmental abnormalities of the cardiovascular system. PMID:22538705

Kowalczyk, Monika S; Hughes, Jim R; Babbs, Christian; Sanchez-Pulido, Luis; Szumska, Dorota; Sharpe, Jacqueline A; Sloane-Stanley, Jacqueline A; Morriss-Kay, Gillian M; Smoot, Leslie B; Roberts, Amy E; Watkins, Hugh; Bhattacharya, Shoumo; Gibbons, Richard J; Ponting, Chris P; Wood, William G; Higgs, Douglas R

2012-08-01

180

Physiological interdependence of the cardiovascular and postural control systems under orthostatic stress.  

PubMed

The cardiovascular system has been observed to respond to changes in human posture and the environment. On the same lines, frequent fallers have been observed to suffer from cardiovascular deficits. The present article aims to demonstrate the existence of interactions between the cardiovascular and postural control systems. The behavior of the two systems under orthostatic challenge was studied through novel adaptations of signal processing techniques. To this effect, the interactions between the two systems were assessed with two metrics, coherence and phase lock value, based on the wavelet transform. Measurements from the cardiovascular system (blood pressure), lower limb muscles (surface electromyography), and postural sway (center of pressure) were acquired from young healthy adults (n = 28, men = 12, age = 20-28 yr) during quiet stance. The continuous wavelet transform was applied to decompose the representative signals on a time-scale basis in a frequency region of 0.01 to 0.1 Hz. Their linear coupling was quantified through a coherence metric, and the synchrony was characterized via the phase information. The outcomes of this study present evidence that the cardiovascular and postural control systems work together to maintain homeostasis under orthostatic challenge. The inferences open a new direction of study for effects under abnormalities and extreme environmental conditions. PMID:24858845

Garg, Amanmeet; Xu, Da; Laurin, Alexandre; Blaber, Andrew P

2014-07-15

181

Development of patient specific cardiovascular models predicting dynamics  

E-print Network

. Special attention is paid to the control of blood pressure, cerebral blood flow velocity, and heart rate autoregulation. The barorecepter system controls blood pressure by regulating heart rate (see Fig. 3), vascular control models predicting baroreflex and cerebral autonomic regulation of blood flow and pressure during

182

Changes in diet, cardiovascular risk factors and modelled cardiovascular risk following diagnosis of diabetes: 1-year results from the ADDITION-Cambridge trial cohort  

PubMed Central

Aims To describe change in self-reported diet and plasma vitamin C, and to examine associations between change in diet and cardiovascular disease risk factors and modelled 10-year cardiovascular disease risk in the year following diagnosis of Type 2 diabetes. Methods Eight hundred and sixty-seven individuals with screen-detected diabetes underwent assessment of self-reported diet, plasma vitamin C, cardiovascular disease risk factors and modelled cardiovascular disease risk at baseline and 1 year (n = 736) in the ADDITION-Cambridge trial. Multivariable linear regression was used to quantify the association between change in diet and cardiovascular disease risk at 1 year, adjusting for change in physical activity and cardio-protective medication. Results Participants reported significant reductions in energy, fat and sodium intake, and increases in fruit, vegetable and fibre intake over 1 year. The reduction in energy was equivalent to an average-sized chocolate bar; the increase in fruit was equal to one plum per day. There was a small increase in plasma vitamin C levels. Increases in fruit intake and plasma vitamin C were associated with small reductions in anthropometric and metabolic risk factors. Increased vegetable intake was associated with an increase in BMI and waist circumference. Reductions in fat, energy and sodium intake were associated with reduction in HbA1c, waist circumference and total cholesterol/modelled cardiovascular disease risk, respectively. Conclusions Improvements in dietary behaviour in this screen-detected population were associated with small reductions in cardiovascular disease risk, independently of change in cardio-protective medication and physical activity. Dietary change may have a role to play in the reduction of cardiovascular disease risk following diagnosis of diabetes. PMID:24102972

Savory, L A; Griffin, S J; Williams, K M; Prevost, A T; Kinmonth, A-L; Wareham, N J; Simmons, R K

2014-01-01

183

Cardiovascular physiology in space flight  

NASA Technical Reports Server (NTRS)

The effects of space flight on the cardiovascular system have been studied since the first manned flights. In several instances, the results from these investigations have directly contradicted the predictions based on established models. Results suggest associations between space flight's effects on other organ systems and those on the cardiovascular system. Such findings provide new insights into normal human physiology. They must also be considered when planning for the safety and efficiency of space flight crewmembers.

Charles, John B.; Bungo, Michael W.

1991-01-01

184

Cardiovascular consequences of loss of supraspinal control of the sympathetic nervous system after spinal cord injury  

Microsoft Academic Search

Teasell RW, Arnold JMO, Krassioukov A, Delaney GA. Cardiovascular consequences of loss of supraspinal control of the sympathetic nervous system after spinal cord injury. Arch Phys Med Rehabil 2000;81:506-16. Spinal cord injury (SCI) with resultant quadriplegia or high paraplegia is associated with significant dysfunction of the sympathetic nervous system. This alteration of sympathetic nervous system activity occurs as a consequence

Robert W. Teasell; J. Malcolm O. Arnold; Andrei Krassioukov; Gail A. Delaney

2000-01-01

185

The effects of exercise on blood flow with reference to the human cardiovascular system: a finite element study  

NASA Technical Reports Server (NTRS)

This paper reports on a theoretical investigation into the effects of vasomotion on blood through the human cardiovascular system. The finite element method has been used to analyse the model. Vasoconstriction and vasodilation may be effected either through the action of the central nervous system or autoregulation. One of the conditions responsible for vasomotion is exercise. The proposed model has been solved and quantitative results of flows and pressures due to changing the conductances of specific networks of arterioles, capillaries and venules comprising the arms, legs, stomach and their combinations have been obtained.

Sud, V. K.; Srinivasan, R. S.; Charles, J. B.; Bungo, M. W.

1992-01-01

186

Design and implementation of multimedia display system for electronic cardiovascular conferences with radiological consultation services  

Microsoft Academic Search

We present a networked multimedia display system based on component technologies for the electronic cardiovascular conferences with radiological consultation services. The system consists of two parts: a data acquisition gateway and a multimedia display workstation. The acquisition gateway is used to collect digital data from difference modalities and authorize them in different sessions for conference presentation. The display workstation is

Jianguo Zhang; Johannes N. Stahl; Gaoping Li; H. K. Huang; Jun Liu; Jian Li; Peng Zhou

2000-01-01

187

Imaging the small animal cardiovascular system in real-time with multispectral optoacoustic tomography  

NASA Astrophysics Data System (ADS)

Multispectral Optoacoustic Tomography (MSOT) is an emerging technique for high resolution macroscopic imaging with optical and molecular contrast. We present cardiovascular imaging results from a multi-element real-time MSOT system recently developed for studies on small animals. Anatomical features relevant to cardiovascular disease, such as the carotid arteries, the aorta and the heart, are imaged in mice. The system's fast acquisition time, in tens of microseconds, allows images free of motion artifacts from heartbeat and respiration. Additionally, we present in-vivo detection of optical imaging agents, gold nanorods, at high spatial and temporal resolution, paving the way for molecular imaging applications.

Taruttis, Adrian; Herzog, Eva; Razansky, Daniel; Ntziachristos, Vasilis

2011-03-01

188

Modeling cardiovascular hemodynamics using the lattice Boltzmann method on massively parallel supercomputers  

NASA Astrophysics Data System (ADS)

Accurate and reliable modeling of cardiovascular hemodynamics has the potential to improve understanding of the localization and progression of heart diseases, which are currently the most common cause of death in Western countries. However, building a detailed, realistic model of human blood flow is a formidable mathematical and computational challenge. The simulation must combine the motion of the fluid, the intricate geometry of the blood vessels, continual changes in flow and pressure driven by the heartbeat, and the behavior of suspended bodies such as red blood cells. Such simulations can provide insight into factors like endothelial shear stress that act as triggers for the complex biomechanical events that can lead to atherosclerotic pathologies. Currently, it is not possible to measure endothelial shear stress in vivo, making these simulations a crucial component to understanding and potentially predicting the progression of cardiovascular disease. In this thesis, an approach for efficiently modeling the fluid movement coupled to the cell dynamics in real-patient geometries while accounting for the additional force from the expansion and contraction of the heart will be presented and examined. First, a novel method to couple a mesoscopic lattice Boltzmann fluid model to the microscopic molecular dynamics model of cell movement is elucidated. A treatment of red blood cells as extended structures, a method to handle highly irregular geometries through topology driven graph partitioning, and an efficient molecular dynamics load balancing scheme are introduced. These result in a large-scale simulation of the cardiovascular system, with a realistic description of the complex human arterial geometry, from centimeters down to the spatial resolution of red-blood cells. The computational methods developed to enable scaling of the application to 294,912 processors are discussed, thus empowering the simulation of a full heartbeat. Second, further extensions to enable the modeling of fluids in vessels with smaller diameters and a method for introducing the deformational forces exerted on the arterial flows from the movement of the heart by borrowing concepts from cosmodynamics are presented. These additional forces have a great impact on the endothelial shear stress. Third, the fluid model is extended to not only recover Navier-Stokes hydrodynamics, but also a wider range of Knudsen numbers, which is especially important in micro- and nano-scale flows. The tradeoffs of many optimizations methods such as the use of deep halo level ghost cells that, alongside hybrid programming models, reduce the impact of such higher-order models and enable efficient modeling of extreme regimes of computational fluid dynamics are discussed. Fourth, the extension of these models to other research questions like clogging in microfluidic devices and determining the severity of co-arctation of the aorta is presented. Through this work, a validation of these methods by taking real patient data and the measured pressure value before the narrowing of the aorta and predicting the pressure drop across the co-arctation is shown. Comparison with the measured pressure drop in vivo highlights the accuracy and potential impact of such patient specific simulations. Finally, a method to enable the simulation of longer trajectories in time by discretizing both spatially and temporally is presented. In this method, a serial coarse iterator is used to initialize data at discrete time steps for a fine model that runs in parallel. This coarse solver is based on a larger time step and typically a coarser discretization in space. Iterative refinement enables the compute-intensive fine iterator to be modeled with temporal parallelization. The algorithm consists of a series of prediction-corrector iterations completing when the results have converged within a certain tolerance. Combined, these developments allow large fluid models to be simulated for longer time durations than previously possible.

Randles, Amanda Elizabeth

189

Cyclooxygenase-1, not cyclooxygenase-2, is responsible for physiological production of prostacyclin in the cardiovascular system.  

PubMed

Prostacyclin is an antithrombotic hormone produced by the endothelium, whose production is dependent on cyclooxygenase (COX) enzymes of which two isoforms exist. It is widely believed that COX-2 drives prostacyclin production and that this explains the cardiovascular toxicity associated with COX-2 inhibition, yet the evidence for this relies on indirect evidence from urinary metabolites. Here we have used a range of experimental approaches to explore which isoform drives the production of prostacyclin in vitro and in vivo. Our data show unequivocally that under physiological conditions it is COX-1 and not COX-2 that drives prostacyclin production in the cardiovascular system, and that urinary metabolites do not reflect prostacyclin production in the systemic circulation. With the idea that COX-2 in endothelium drives prostacyclin production in healthy individuals removed, we must seek new answers to why COX-2 inhibitors increase the risk of cardiovascular events to move forward with drug discovery and to enable more informed prescribing advice. PMID:23045674

Kirkby, Nicholas S; Lundberg, Martina H; Harrington, Louise S; Leadbeater, Philip D M; Milne, Ginger L; Potter, Claire M F; Al-Yamani, Malak; Adeyemi, Oladipupo; Warner, Timothy D; Mitchell, Jane A

2012-10-23

190

Predictors of the first cardiovascular event in patients with systemic lupus erythematosus - a prospective cohort study  

PubMed Central

Introduction Cardiovascular disease (CVD) is a major cause of premature mortality among Systemic lupus erythematosus (SLE) patients. Many studies have measured and evaluated risk factors for premature subclinical atherosclerosis, but few studies are prospective and few have evaluated risk factors for hard endpoints, i.e. clinically important cardiovascular events (CVE). We investigated the impact of traditional and lupus associated risk factors for the first ever CVE in a longitudinal cohort of SLE patients. Methods A total of 182 SLE patients (mean age 43.9 years) selected to be free of CVE were included. Cardiovascular and autoimmune biomarkers were measured on samples collected after overnight fasting at baseline. Clinical information was collected at baseline and at follow up. End point was the first ever CVE (ischemic heart, cerebrovascular or peripheral vascular disease or death due to CVD). Impact of baseline characteristics/biomarkers on the risk of having a first CVE was evaluated with Cox regression. Results Follow up was 99.5% after a mean time of 8.3 years. Twenty-four patients (13%) had a first CVE. In age-adjusted Cox regression, any positive antiphospholipid antibody (aPL), elevated markers of endothelial activation (von Willebrand factor (vWf), soluble vascular cellular adhesion molecule-1 (sVCAM-1)) and fibrinogen predicted CVEs. Of SLE manifestations, arthritis, pleuritis and previous venous occlusion were positively associated with future CVEs while thrombocytopenia was negatively associated. Among traditional risk factors only age and smoking were significant predictors. In a multivariable Cox regression model age, any positive aPL, vWf and absence of thrombocytopenia were all predictors of the first CVE. Conclusions In addition to age, positive aPL, biomarkers indicating increased endothelial cell activity/damage, and absence of thrombocytopenia were independent predictors of CVEs in this prospective study. Our results indicate that activation of the endothelium and the coagulation system are important features in SLE related CVD. Furthermore, we observed that the risk of CVEs seems to differ between subgroups of SLE patients. PMID:20003285

2009-01-01

191

Job strain (demands and control model) as a predictor of cardiovascular risk factors among petrochemical personnel  

PubMed Central

Background: One of the practical models for the assessment of stressful working conditions due to job strain is job demand and control model, which explains how physical and psychological adverse consequences, including cardiovascular risk factors can be established due to high work demands (the amount of workload, in addition to time limitations to complete that work) and low control of the worker on his/her work (lack of decision making) in the workplace. The aim of this study was to investigate how certain cardiovascular risk factors (including body mass index [BMI], heart rate, blood pressure, cholesterol and smoking) and the job demand and job control are related to each other. Materials and Methods: This prospective cohort study was conducted on 500 workers of the petrochemical industry in south of Iran, 2009. The study population was selected using simple random statistical method. They completed job demand and control questionnaire. The cardiovascular risk factors data was extracted from the workers hygiene profiles. Chi-square (?2) test and hypothesis test (?) were used to assess the possible relationship between different quantified variables, individual demographic and cardiovascular risk factors. Results: The results of this study revealed that a significant relationship can be found between job demand control model and cardiovascular risk factors. Chi-square test result for the heart rate showed the highest (?2 = 145.078) relationship, the corresponding results for smoking and BMI were ?2 = 85.652 and ?2 = 30.941, respectively. Subsequently, hypothesis testing results for cholesterol and hypertension was 0.469 and 0.684, respectively. Discussion: Job strain is likely to be associated with an increased risk of cardiovascular risk factors among male staff in a petrochemical company in Iran. The parameters illustrated in the Job demands and control model can act as acceptable predictors for the probability of job stress occurrence followed by showing a high trend of CVD risk factors. PMID:25861661

Habibi, Ehsanollah; Poorabdian, Siamak; Shakerian, Mahnaz

2015-01-01

192

Implementation strategies of Systems Medicine in clinical research and home care for cardiovascular disease patients.  

PubMed

Insights from the "-omics" science have recently emphasized the need to implement an overall strategy in medical research. Here, the development of Systems Medicine has been indicated as a potential tool for clinical translation of basic research discoveries. Systems Medicine also gives the opportunity of improving different steps in medical practice, from diagnosis to healthcare management, including clinical research. The development of Systems Medicine is still hampered however by several challenges, the main one being the development of computational tools adequate to record, analyze and share a large amount of disparate data. In addition, available informatics tools appear not yet fully suitable for the challenge because they are not standardized, not universally available, or with ethical/legal concerns. Cardiovascular diseases (CVD) are a very promising area for translating Systems Medicine into clinical practice. By developing clinically applied technologies, the collection and analysis of data may improve CV risk stratification and prediction. Standardized models for data recording and analysis can also greatly broaden data exchange, thus promoting a uniform management of CVD patients also useful for clinical research. This advance however requires a great organizational effort by both physicians and health institutions, as well as the overcoming of ethical problems. This narrative review aims at providing an update on the state-of-art knowledge in the area of Systems Medicine as applied to CVD, focusing on current critical issues, providing a road map for its practical implementation. PMID:25283057

Montecucco, Fabrizio; Carbone, Federico; Dini, Frank Lloyd; Fiuza, Manuela; Pinto, Fausto J; Martelli, Antonietta; Palombo, Domenico; Sambuceti, Gianmario; Mach, François; De Caterina, Raffaele

2014-11-01

193

Sympathetic neural activity to the cardiovascular system: integrator of systemic physiology and interindividual characteristics.  

PubMed

The sympathetic nervous system is a ubiquitous, integrating controller of myriad physiological functions. In the present article, we review the physiology of sympathetic neural control of cardiovascular function with a focus on integrative mechanisms in humans. Direct measurement of sympathetic neural activity (SNA) in humans can be accomplished using microneurography, most commonly performed in the peroneal (fibular) nerve. In humans, muscle SNA (MSNA) is composed of vasoconstrictor fibers; its best-recognized characteristic is its participation in transient, moment-to-moment control of arterial blood pressure via the arterial baroreflex. This property of MSNA contributes to its typical "bursting" pattern which is strongly linked to the cardiac cycle. Recent evidence suggests that sympathetic neural mechanisms and the baroreflex have important roles in the long term control of blood pressure as well. One of the striking characteristics of MSNA is its large interindividual variability. However, in young, normotensive humans, higher MSNA is not linked to higher blood pressure due to balancing influences of other cardiovascular variables. In men, an inverse relationship between MSNA and cardiac output is a major factor in this balance, whereas in women, beta-adrenergic vasodilation offsets the vasoconstrictor/pressor effects of higher MSNA. As people get older (and in people with hypertension) higher MSNA is more likely to be linked to higher blood pressure. Skin SNA (SSNA) can also be measured in humans, although interpretation of SSNA signals is complicated by multiple types of neurons involved (vasoconstrictor, vasodilator, sudomotor and pilomotor). In addition to blood pressure regulation, the sympathetic nervous system contributes to cardiovascular regulation during numerous other reflexes, including those involved in exercise, thermoregulation, chemoreflex regulation, and responses to mental stress. PMID:24715570

Charkoudian, N; Wallin, B G

2014-04-01

194

A Follow-Up Study of Medical Students' Biomedical Understanding and Clinical Reasoning Concerning the Cardiovascular System  

ERIC Educational Resources Information Center

Novice medical students usually hold initial conceptions concerning medical domains, such as the cardiovascular system, which may contradict scientific explanations and thus hinder learning. The purpose of this study was to investigate which kinds of biomedical representations medical students constructed of the central cardiovascular system in…

Ahopelto, Ilona; Mikkila-Erdmann, Mirjamaija; Olkinuora, Erkki; Kaapa, Pekka

2011-01-01

195

Mouse models to study the effect of cardiovascular risk factors on brain structure and cognition  

PubMed Central

Recent clinical data indicates that hemodynamic changes caused by cardiovascular diseases such as atherosclerosis, heart failure, and hypertension affect cognition. Yet, the underlying mechanisms of the resulting vascular cognitive impairment (VCI) are poorly understood. One reason for the lack of mechanistic insights in VCI is that research in dementia primarily focused on Alzheimer's disease models. To fill in this gap, we critically reviewed the published data and various models of VCI. Typical findings in VCI include reduced cerebral perfusion, blood–brain barrier alterations, white matter lesions, and cognitive deficits, which have also been reported in different cardiovascular mouse models. However, the tests performed are incomplete and differ between models, hampering a direct comparison between models and studies. Nevertheless, from the currently available data we conclude that a few existing surgical animal models show the key features of vascular cognitive decline, with the bilateral common carotid artery stenosis hypoperfusion mouse model as the most promising model. The transverse aortic constriction and myocardial infarction models may be good alternatives, but these models are as yet less characterized regarding the possible cerebral changes. Mixed models could be used to study the combined effects of different cardiovascular diseases on the deterioration of cognition during aging. PMID:23963364

Bink, Diewertje I; Ritz, Katja; Aronica, Eleonora; van der Weerd, Louise; Daemen, Mat JAP

2013-01-01

196

Role Models and the Psychological Characteristics That Buffer Low-Socioeconomic-Status Youth from Cardiovascular Risk  

ERIC Educational Resources Information Center

Little is understood about why some youth from low-socioeconomic-status (SES) environments exhibit good health despite adversity. This study tested whether role models and "shift-and-persist" approaches (reframing stressors more benignly while persisting with future optimism) protect low-SES youth from cardiovascular risk. A total of 163…

Chen, Edith; Lee, William K.; Cavey, Lisa; Ho, Amanda

2013-01-01

197

Iron, oxidative stress, and redox signaling in the cardiovascular system.  

PubMed

The redox state of the cell is predominantly dependent on an iron redox couple and is maintained within strict physiological limits. Iron is an essential metal for hemoglobin synthesis in erythrocytes, for oxidation-reduction reactions, and for cellular proliferation. The maintenance of stable iron concentrations requires the coordinated regulation of iron transport into plasma from dietary sources in the duodenum, from recycled senescent red cells in macrophages, and from storage in hepatocytes. The absorption of dietary iron, which is present in heme or nonheme form, is carried out by mature villus enterocytes of the duodenum and proximal jejunum. Multiple physiological processes are involved in maintaining iron homeostasis. These include its storage at the intracellular and extracellular level. Control of iron balance in the whole organism requires communication between sites of uptake, utilization, and storage. Key protein transporters and the molecules that regulate their activities have been identified. In this field, ferritins and hepcidin are the major regulator proteins. A variety of transcription factors may be activated depending on the level of oxidative stress, leading to the expression of different genes. Major preclinical and clinical trials have shown advances in iron-chelation therapy for the treatment of iron-overload disease as well as cardiovascular and chronic inflammatory diseases. PMID:24888568

Gudjoncik, Aurélie; Guenancia, Charles; Zeller, Marianne; Cottin, Yves; Vergely, Catherine; Rochette, Luc

2014-08-01

198

TEMPORAL ASSOCIATION BETWEEN PULMONARY AND SYSTEMIC EFFECTS OF PARTICULATE MATTER IN HEALTHY AND CARDIOVASCULAR COMPROMISED RATS  

EPA Science Inventory

Temporal association between pulmonary and systemic effects of particulate matter in healthy and cardiovascular compromised ratsUrmila P. Kodavanti, Mette C. Schladweiler, Allen D. Ledbetter, Russ Hauser*, David C. Christiani*, John McGee, Judy R. Richards, Daniel L. Co...

199

System identification of closed-loop cardiovascular control: effects of posture and autonomic blockade  

NASA Technical Reports Server (NTRS)

We applied system identification to the analysis of fluctuations in heart rate (HR), arterial blood pressure (ABP), and instantaneous lung volume (ILV) to characterize quantitatively the physiological mechanisms responsible for the couplings between these variables. We characterized two autonomically mediated coupling mechanisms [the heart rate baroreflex (HR baroreflex) and respiratory sinus arrhythmia (ILV-HR)] and two mechanically mediated coupling mechanisms [the blood pressure wavelet generated with each cardiac contraction (circulatory mechanics) and the direct mechanical effects of respiration on blood pressure (ILV-->ABP)]. We evaluated the method in humans studied in the supine and standing postures under control conditions and under conditions of beta-sympathetic and parasympathetic pharmacological blockades. Combined beta-sympathetic and parasympathetic blockade abolished the autonomically mediated couplings while preserving the mechanically mediated coupling. Selective autonomic blockade and postural changes also altered the couplings in a manner consistent with known physiological mechanisms. System identification is an "inverse-modeling" technique that provides a means for creating a closed-loop model of cardiovascular regulation for an individual subject without altering the underlying physiological control mechanisms.

Mullen, T. J.; Appel, M. L.; Mukkamala, R.; Mathias, J. M.; Cohen, R. J.

1997-01-01

200

Hydrogen Peroxide Sensing and Signaling by Protein Kinases in the Cardiovascular System  

PubMed Central

Abstract Significance: Oxidants were once principally considered perpetrators of injury and disease. However, this has become an antiquated view, with cumulative evidence showing that the oxidant hydrogen peroxide serves as a signaling molecule. Hydrogen peroxide carries vital information about the redox state of the cell and is crucial for homeostatic regulation during health and adaptation to stress. Recent Advances: In this review, we examine the contemporary concepts for how hydrogen peroxide is sensed and transduced into a biological response by introducing post-translational oxidative modifications on select proteins. Oxidant sensing and signaling by kinases are of particular importance as they integrate oxidant signals into phospho-regulated pathways. We focus on CAMKII, PKA, and PKG, kinases whose redox regulation has notable impact on cardiovascular function. Critical Issues: In addition, we examine the mechanism for regulating intracellular hydrogen peroxide, considering the net concentrations that may accumulate. The effects of endogenously generated oxidants are often modeled by applying exogenous hydrogen peroxide to cells or tissues. Here we consider whether model systems exposed to exogenous hydrogen peroxide have relevance to systems where the oxidant is generated endogenously, and if so, what concentration can be justified in terms of relevance to health and disease. Future Directions: Improving our understanding of hydrogen peroxide signaling and the sensor proteins that it can modify will help us develop new strategies to regulate intracellular signaling to prevent disease. Antioxid. Redox Signal. 18, 1042–1052. PMID:22867279

Burgoyne, Joseph R.; Oka, Shin-ichi; Ale-Agha, Niloofar

2013-01-01

201

Risk factors for cardiovascular mortality in patients with systemic lupus erythematosus, a prospective cohort study  

PubMed Central

Introduction Systemic lupus erythematosus (SLE) is a chronic autoimmune disease. Cardiovascular disease (CVD) is common and a major cause of mortality. Studies on cardiovascular morbidity are abundant, whereas mortality studies focusing on cardiovascular outcomes are scarce. The aim of this study was to investigate causes of death and baseline predictors of overall (OM), non-vascular (N-VM), and specifically cardiovascular (CVM) mortality in SLE, and to evaluate systematic coronary risk evaluation (SCORE). Methods 208 SLE patients were included 1995-1999 and followed up after 12 years. Clinical evaluation, CVD risk factors, and biomarkers were recorded at inclusion. Death certificates and autopsy protocols were collected. Causes of death were divided into CVM (ischemic vascular and general atherosclerotic diseases), N-VM and death due to pulmonary hypertension. Predictors of mortality were investigated using multivariable Cox regression. SCORE and standardized mortality ratio (SMR) were calculated. Results During follow-up 42 patients died at mean age of 62 years. SMR 2.4 (CI 1.7-3.0). 48% of deaths were caused by CVM. SCORE underestimated CVM but not to a significant level. Age, high cystatin C levels and established arterial disease were the strongest predictors for all- cause mortality. After adjusting for these in multivariable analyses, only smoking among traditional risk factors, and high soluble vascular cell adhesion molecule-1 (sVCAM-1), high sensitivity C-reactive protein (hsCRP), anti-beta2 glycoprotein-1 (abeta2GP1) and any antiphospholipid antibody (aPL) among biomarkers, remained predictive of CVM. Conclusion With the exception of smoking, traditional risk factors do not capture the main underlying risk factors for CVM in SLE. Rather, cystatin C levels, inflammatory and endothelial markers, and antiphospholipid antibodies (aPL) differentiate patients with favorable versus severe cardiovascular prognosis. Our results suggest that these new biomarkers are useful in evaluating the future risk of cardiovascular mortality in SLE patients. PMID:22390680

2012-01-01

202

Experimental Models of Oxidative Stress Related to Cardiovascular Diseases and Diabetes  

Microsoft Academic Search

\\u000a In this chapter we summarize the commonly used animal models employed in the study of cardiovascular diseases and diabetes,\\u000a two of the most prevalent oxidative stress-induced diseases. A number of animal models of atherosclerosis support the notion\\u000a that reactive oxygen and nitrogen species have a causal role in atherosclerosis and other vascular diseases. Experimental\\u000a atherosclerosis is induced by specific lipid-rich

Maria D. Mesa; Concepcion M. Aguilera; Angel Gil

203

Space Weather and a State of Cardiovascular System of Human Being with a Weakened Adaptation System  

NASA Astrophysics Data System (ADS)

As has been shown in [Samsonov et al., 2013] even at the considerable disturbances of space weather parameters a healthy human being did not undergo painful symptoms although measurements of objective physiological indices showed their changes. At the same time the state of health of people with the weakened adaptation system under the same conditions can considerably be deteriorated up to fatal outcome. The analysis of results of the project "Heliomed" and the number of calls for the emergency medical care (EMC) around Yakutsk as to cardiovascular diseases (CVD) has shown:- the total number of calls for EMC concerning myocardial infarction (MI) per year near the geomagnetic disturbance maximum (1992) exceeds the number of calls per year near the geomagnetic activity minimum (1998) by a factor of 1,5 and concerning to strokes - by a factor of 1,8.- maxima of MI are observed during spring and autumn periods coinciding with maxima of geophysical disturbance;- the coincidence of 30-32 daily periods in a power spectrum of MI with the same periods in power spectra of space weather parameters (speeds and density of the solar wind, interplanetary magnetic field, geophysical disturbance);- the existence of 3 maxima of the number of calls for EMC: a) at the moment of disturbance on the Sun; during a geophysical disturbance (in 2-4 days after a disturbance on the Sun); in 2-4 days after a geophysical disturbance;- the availability of coincidence of insignificant disturbances of space weather parameters with changes of the functional state of cardiovascular system of a human being with the weakened adaptation system and the occurrence of MI and strokes at considerable values of such disturbances is explained by a quasi-logarithmic dependence of the response of human being organisms to the environment disturbance intensity.

Samsonov, S. N.

204

Cardiovascular and other dynamic systems in long-term space flight  

NASA Technical Reports Server (NTRS)

The paper examines the physiology of the cardiovascular system, and to a lesser extent the endocrine, renal, and hematopoietic systems. The paper highlights the aspects of these areas that are most pertinent to space manufacturing, i.e., working in space. Areas covered include the physiological costs of working in microgravity and partial gravity (e.g., the moon or Mars), countermeasures to potentially adverse physiological adaptations, and problems associated with return to earth after long periods of weightlessness.

Tipton, David A.

1987-01-01

205

The Applicability of Nonlinear Systems Dynamics Chaos Measures to Cardiovascular Physiology Variables  

NASA Technical Reports Server (NTRS)

Three measures of nonlinear chaos (fractal dimension, Approximate Entropy (ApEn), and Lyapunov exponents) were studied as potential measures of cardiovascular condition. It is suggested that these measures have potential in the assessment of cardiovascular condition in environments of normal cardiovascular stress (normal gravity on the Earth surface), cardiovascular deconditioning (microgravity of space), and increased cardiovascular stress (lower body negative pressure (LBNP) treatments).

Hooker, John C.

1991-01-01

206

S-Nitrosothiols and the S-Nitrosoproteome of the Cardiovascular System  

PubMed Central

Abstract Significance: Since their discovery in the early 1990's, S-nitrosylated proteins have been increasingly recognized as important determinants of many biochemical processes. Specifically, S-nitrosothiols in the cardiovascular system exert many actions, including promoting vasodilation, inhibiting platelet aggregation, and regulating Ca2+ channel function that influences myocyte contractility and electrophysiologic stability. Recent Advances: Contemporary developments in liquid chromatography–mass spectrometry methods, the development of biotin- and His-tag switch assays, and the availability of cyanide dye-labeling for S-nitrosothiol detection in vitro have increased significantly the identification of a number of cardiovascular protein targets of S-nitrosylation in vivo. Critical Issues: Recent analyses using modern S-nitrosothiol detection techniques have revealed the mechanistic significance of S-nitrosylation to the pathophysiology of numerous cardiovascular diseases, including essential hypertension, pulmonary hypertension, ischemic heart disease, stroke, and congestive heart failure, among others. Future Directions: Despite enhanced insight into S-nitrosothiol biochemistry, translating these advances into beneficial pharmacotherapies for patients with cardiovascular diseases remains a primary as-yet unmet goal for investigators within the field. Antioxid. Redox Signal. 18, 270–287. PMID:22770551

Maron, Bradley A.; Tang, Shiow-Shih

2013-01-01

207

Air pollution and its impact on the cardiovascular system Poluição atmosférica e seu impacto no sistema cardiovascular  

Microsoft Academic Search

Despite the great medical advances, cardiovascular disease remains one of the major causes of mortality worldwide, especially in industrialized countries. It develops as a result of countless complex interactions between genetic factors such as those related to age, sex, family history, weight, and post-menopausal status in women; and to environment-related factors such as cigarette smoking, alcohol use, eating habits, physical

Marjorie Paris Colombini

208

Poluição atmosférica e seu impacto no sistema cardiovascular Air pollution and its impact on the cardiovascular system  

Microsoft Academic Search

Despite the great medical advances, cardiovascular disease remains one of the major causes of mortality worldwide, especially in industrialized countries. It develops as a result of countless complex interactions between genetic factors such as those related to age, sex, family history, weight, and post-menopausal status in women; and to environment-related factors such as cigarette smoking, alcohol use, eating habits, physical

Marjorie Paris Colombini

209

Characterization of Coherent Structures in the Cardiovascular System  

PubMed Central

Recent advances in blood flow modeling have provided highly resolved, four-dimensional data of fluid mechanics in large vessels. The motivation for such modeling is often to better understand how flow conditions relate to health and disease, or to evaluate interventions that affect, or are affected by, blood flow mechanics. Vessel geometry and the pulsatile pumping of blood leads to complex flow, which is often difficult to characterize. This article discusses a computational method to better characterize blood flow kinematics. In particular, we compute Lagrangian coherent structures (LCS) to study flow in large vessels. We demonstrate that LCS can be used to characterize flow stagnation, flow separation, partitioning of fluid to downstream vasculature, and mechanisms governing stirring and mixing in vascular models. This perspective allows valuable under-standing of flow features in large vessels beyond methods traditionally considered. PMID:18437573

Shadden, Shawn C.; Taylor, Charles A.

2013-01-01

210

Investigating autonomic control of the cardiovascular system: a battery of simple tests.  

PubMed

Sympathetic and parasympathetic divisions of the autonomic nervous system constantly control the heart (sympathetic and parasympathetic divisions) and blood vessels (predominantly the sympathetic division) to maintain appropriate blood pressure and organ blood flow over sometimes widely varying conditions. This can be adversely affected by pathological conditions that can damage one or both branches of autonomic control. The set of teaching laboratory activities outlined here uses various interventions, namely, 1) the heart rate response to deep breathing, 2) the heart rate response to a Valsalva maneuver, 3) the heart rate response to standing, and 4) the blood pressure response to standing, that cause fairly predictable disturbances in cardiovascular parameters in normal circumstances, which serve to demonstrate the dynamic control of the cardiovascular system by autonomic nerves. These tests are also used clinically to help investigate potential damage to this control. PMID:24292919

Johnson, Christopher D; Roe, Sean; Tansey, Etain A

2013-12-01

211

Toxic Effects of Mercury on the Cardiovascular and Central Nervous Systems  

PubMed Central

Environmental contamination has exposed humans to various metal agents, including mercury. This exposure is more common than expected, and the health consequences of such exposure remain unclear. For many years, mercury was used in a wide variety of human activities, and now, exposure to this metal from both natural and artificial sources is significantly increasing. Many studies show that high exposure to mercury induces changes in the central nervous system, potentially resulting in irritability, fatigue, behavioral changes, tremors, headaches, hearing and cognitive loss, dysarthria, incoordination, hallucinations, and death. In the cardiovascular system, mercury induces hypertension in humans and animals that has wide-ranging consequences, including alterations in endothelial function. The results described in this paper indicate that mercury exposure, even at low doses, affects endothelial and cardiovascular function. As a result, the reference values defining the limits for the absence of danger should be reduced. PMID:22811600

Fernandes Azevedo, Bruna; Barros Furieri, Lorena; Peçanha, Franck Maciel; Wiggers, Giulia Alessandra; Frizera Vassallo, Paula; Ronacher Simões, Maylla; Fiorim, Jonaina; Rossi de Batista, Priscila; Fioresi, Mirian; Rossoni, Luciana; Stefanon, Ivanita; Alonso, María Jesus; Salaices, Mercedes; Valentim Vassallo, Dalton

2012-01-01

212

Probing Human Cardiovascular Congenital Disease Using Transgenic Mouse Models  

PubMed Central

Congenital heart defects (CHDs) impact in utero embryonic viability, children, and surviving adults. Since the first transfer of genes into mice, transgenic mouse models have enabled researchers to experimentally study and genetically test the roles of genes in development, physiology, and disease progression. Transgenic mice have become a bona fide human CHD pathology model and their use has dramatically increased within the past two decades. Now that the entire mouse and human genomes are known, it is possible to knock out, mutate, misexpress, and/or replace every gene. Not only have transgenic mouse models changed our understanding of normal development, CHD processes, and the complex interactions of genes and pathways required during heart development, but they are also being used to identify new avenues for medical therapy. PMID:21377625

Snider, Paige; Conway, Simon J.

2013-01-01

213

Naturally Occurring and Iatrogenic Animal Models of Valvular, Infectious, and Arrhythmic Cardiovascular Disease  

Microsoft Academic Search

Most naturally occurring congenital cardiovascular entities found in humans have been identified in one or more species of\\u000a animals but the utility of these naturally occurring models as research subjects is not well established. Many of the congenital\\u000a diseases are associated with noncardiovascular defects and some of these may result in infertility, impotence, and other reproductive\\u000a problems that preclude the

David R. Gross

214

What Research Says: The Cardiovascular System: Children's Conceptions and Misconceptions.  

ERIC Educational Resources Information Center

Reports findings of a study on children's perceptions and alternate conceptions about the human circulatory system. Summarizes the responses of fifth and eighth grade students on questions dealing with the heart and blood. Offers examples of hands-on activities and confrontation strategies that address common misconceptions on circulation. (ML)

Arnaudin, Mary W.; Mintzes, Joel J.

1986-01-01

215

Effect of Selective Blockade of ?2-Adrenoceptor Subtypes on Cardiovascular System in Rats.  

PubMed

Selective blockade of various ?2-adrenoceptors exerts various effects on the cardiovascular system in rats. Blockade of ?2A/D-adrenoceptors in experimental animals decelerates and then accelerates HR. Blockade of ?2B-adrenoceptors produces a negative chronotropic effect; blockade of ?2C-adrenoceptors has a positive chronotropic effect. Administration of selective blockers of ?2A/D- and ?2B-adrenoceptors causes hypotension, while selective blockade of ?2C-adrenoceptors increases BP. PMID:25711659

Zefirov, T L; Khisamieva, L I; Ziyatdinova, N I; Zefirov, A L

2015-02-01

216

Nonlinear systems dynamics in cardiovascular physiology: The heart rate delay map and lower body negative pressure  

NASA Technical Reports Server (NTRS)

A preliminary study of the applicability of nonlinear dynamic systems analysis techniques to low body negative pressure (LBNP) studies. In particular, the applicability of the heart rate delay map is investigated. It is suggested that the heart rate delay map has potential as a supplemental tool in the assessment of subject performance in LBNP tests and possibly in the determination of susceptibility to cardiovascular deconditioning with spaceflight.

Hooker, John C.

1990-01-01

217

Patient-Specific Modeling of Cardiovascular Dynamics with a Major Role for Adaptation  

Microsoft Academic Search

\\u000a Over the last few decades, technological developments have made diagnostic information of the cardiovascular system far more\\u000a detailed. These improvements are prominently attributed to the general availability of many imaging techniques, such as ultrasonic\\u000a echo imaging, computer tomography (CT), Magnetic Resonance Imaging (MRI), and Positron Emission Tomography (PET). After primary\\u000a diagnosis, treatment starts by following a protocol that is considered

Theo Arts; Joost Lumens; Wilco Kroon; Dirk Donker; Frits Prinzen; Tammo Delhaas

218

Numerical fatigue life assessment of cardiovascular stents: A two-scale plasticity-damage model  

NASA Astrophysics Data System (ADS)

Cardiovascular disease has become a major global health care problem in the last decades. To tackle this problem, the use of cardiovascular stents has been considered a promising and effective approach. Numerical simulations to evaluate the in vivo behavior of stents are becoming more and more important to assess potential failures. As the material failure of a stent device has been often associated with fatigue issues, numerical approaches for fatigue life assessment of stents have gained special interest in the engineering community. Numerical fatigue life predictions can be used to modify the design and prevent failure without making and testing numerous physical devices, thus preventing from undesired fatigue failures. We present a numerical fatigue life model for the analysis of cardiovascular balloon-expandable stainless steel stents that can hopefully provide useful information either to be used for product improvement or for clinicians to make life-saving decisions. This model incorporates a two-scale continuum damage mechanics model and the so-called Soderberg fatigue failure criterion. We provide numerical results for both Palmaz-Schatz and Cypher stent designs and demonstrate that a good agreement is found between the numerical and the available experimental results.

Santos, H. A. F. A.; Auricchio, F.; Conti, M.

2013-07-01

219

Technological Innovations in the Development of Cardiovascular Clinical Information Systems  

Microsoft Academic Search

Recent studies have shown that computerized clinical case management and decision support systems can be used to assist surgeons\\u000a in the diagnosis of disease, optimize surgical operation, aid in drug therapy and decrease the cost of medical treatment.\\u000a Therefore, medical informatics has become an extensive field of research and many of these approaches have demonstrated potential\\u000a value for improving medical

Nan-Chen Hsieh; Chung-Yi Chang; Kuo-Chen Lee; Jeen-Chen Chen; Chien-Hui Chan

220

Systolic time interval data acquisition system. Specialized cardiovascular studies  

NASA Technical Reports Server (NTRS)

The development of a data acquisition system for noninvasive measurement of systolic time intervals is described. R-R interval from the ECG determines instantaneous heart rate prior to the beat to be measured. Total electromechanical systole (Q-S2) is measured from the onset of the ECG Q-wave to the onset of the second heart sound (S2). Ejection time (ET or LVET) is measured from the onset of carotid upstroke to the incisure. Pre-ejection period (PEP) is computed by subtracting ET from Q-S2. PEP/ET ratio is computed directly.

Baker, J. T.

1976-01-01

221

Nnuclear uptake and retention of a synthetic progestin in the cardiovascular system of the baboon  

SciTech Connect

It has long been known that there is a sexual dimorphism in the incidence of coronary heart disease. This observation, together with more recent reports of increased cardiovascular disease associated with the use of oral contraceptives, led to a search for steroid receptors in the cardiovascular system. In this study the nuclear uptake and retention of a synthetic progestin was examined in the cardiovascular system of the baboons. Long term oophorectomized baboons were primed with estradiol benzoate for 3 days before the experiment (50 micrograms/kg, im) and adrenalectomized 2 days before the experiment. On the day of the experiment, the animals were injected under anesthesia with 2.5 micrograms/kg BW (/sup 3/H)ORG 2058 (16 alpha-ethyl-21-hydroxy-19-nor-(6,7-/sup 3/H)pregn-4-ene-3,20-dione) or with (/sup 3/H) ORG 2058 plus a 1000-fold excess of unlabeled progesterone (control). One hour after the injection, the animals were rapidly exsanguinated, and parts of the cardiovascular system were removed and processed for autoradiography. Localization of the synthetic progestin was found in nuclei of between 25-75% of all smooth muscle cells of the media of all arteries examined and to a lesser extent in the nuclei of the fibroblasts and others cells of the adventitia. Localization of the synthetic progestin in the heart was limited to approximately 1% of the myocardial cells and less than 5% of interstitial cell nuclei. The pattern of localization found differs from that for estrogen and androgen and suggests the possible presence of estrogen-independent progesterone receptors in smooth muscle cells of the media of the aorta and coronary arteries.

Sheridan, P.J.; McGill, H.C. Jr.

1984-06-01

222

A Simple Chinese Risk Score Model for Screening Cardiovascular Autonomic Neuropathy  

PubMed Central

Background The purpose of the present study was to develop and evaluate a risk score to predict people at high risk of cardiovascular autonomic dysfunction neuropathy (CAN) in Chinese population. Methods and Materials A population-based sample of 2,092 individuals aged 30–80 years, without previously diagnosed CAN, was surveyed between 2011 and 2012. All participants underwent short-term HRV test. The risk score was derived from an exploratory set. The risk score was developed by stepwise backward multiple logistic regression. The coefficients from this model were transformed into components of a CAN score. This score was tested in a validation and entire sample. Results The final risk score included age, body mass index, hypertension, resting hear rate, items independently and significantly (P<0.05) associated with the presence of previously undiagnosed CAN. The area under the receiver operating curve was 0.726 (95% CI 0.686–0.766) for exploratory set, 0.784 (95% CI 0.749–0.818) for validation set, and 0.756 (95% CI 0.729–0.782) for entire sample. In validation set, at optimal cutoff score of 5 of 10, the risk score system has the sensitivity, specificity, and percentage that needed subsequent testing were 69, 78, and 30%, respectively. Conclusion We developed a CAN risk score system based on a set of variables not requiring laboratory tests. The score system is simple fast, inexpensive, noninvasive, and reliable tool that can be applied to early intervention to delay or prevent the disease in China. PMID:24621478

Zeng, Fangfang; Tang, Zi-Hui; Wang, Ying-Wei

2014-01-01

223

The use of animal models in developing the discipline of cardiovascular tissue engineering: a review.  

PubMed

Cardiovascular disease remains one of the major causes of death and disability in the Western world. Tissue engineering offers the prospect of being able to meet the demand for replacement of heart valves, vessels for coronary and lower limb bypass surgery and the generation of cardiac tissue for addition to the diseased heart. In order to test prospective tissue-engineered devices, these constructs must first be proven in animal models before receiving CE marking or FDA approval for a clinical trial. The choice of animal depends on the nature of the tissue-engineered construct being tested. Factors that need to be considered include technical requirements of implanting the construct, availability of the animal, cost and ethical considerations. In this paper, we review the history of animal studies in cardiovascular tissue engineering and the uses of animal tissue as sources for tissue engineering. PMID:14697864

Rashid, S Tawqeer; Salacinski, Henryk J; Hamilton, George; Seifalian, Alexander M

2004-04-01

224

Physical activity ameliorates cardiovascular health in elderly subjects: the functional role of the ? adrenergic system  

PubMed Central

Aging is a complex process characterized by a gradual decline in organ functional reserves, which eventually reduces the ability to maintain homeostasis. An exquisite feature of elderly subjects, which constitute a growing proportion of the world population, is the high prevalence of cardiovascular disorders, which negatively affect both the quality of life and the life expectancy. It is widely acknowledged that physical activity represents one of the foremost interventions capable in reducing the health burden of cardiovascular disease. Interestingly, the benefits of moderate-intensity physical activity have been established both in young and elderly subjects. Herein we provide a systematic and updated appraisal of the literature exploring the pathophysiological mechanisms evoked by physical activity in the elderly, focusing on the functional role of the ? adrenergic system. PMID:23964243

Santulli, Gaetano; Ciccarelli, Michele; Trimarco, Bruno; Iaccarino, Guido

2013-01-01

225

Injected nanoparticles: the combination of experimental systems to assess cardiovascular adverse effects.  

PubMed

When nanocarriers are used for drug delivery they can often achieve superior therapeutic outcomes over standard drug formulations. However, concerns about their adverse effects are growing due to the association between exposure to certain nanosized particles and cardiovascular events. Here we examine the impact of intravenously injected drug-free nanocarriers on the cardiovasculature at both the systemic and organ levels. We combine in vivo and in vitro methods to enable monitoring of hemodynamic parameters in conscious rats, assessments of the function of the vessels after sub-chronic systemic exposure to nanocarriers and evaluation of the direct effect of nanocarriers on vascular tone. We demonstrate that nanocarriers can decrease blood pressure and increase heart rate in vivo via various mechanisms. Depending on the type, nanocarriers induce the dilation of the resistance arteries and/or change the responses induced by vasoconstrictor or vasodilator drugs. No direct correlation between physicochemical properties and cardiovascular effects of nanoparticles was observed. The proposed combination of methods empowers the studies of cardiovascular adverse effects of the nanocarriers. PMID:24530427

Vlasova, Maria A; Tarasova, Olga S; Riikonen, Joakim; Raula, Janne; Lobach, Anatoly S; Borzykh, Anna A; Smirin, Boris V; Kauppinen, Esko I; Eletskii, Alexander V; Herzig, Karl-Heinz; Salonen, Jarno; Tavi, Pasi; Lehto, Vesa-Pekka; Järvinen, Kristiina

2014-05-01

226

OCT imaging of the musculoskeletal and cardiovascular systems  

NASA Astrophysics Data System (ADS)

In this presentation, the application of optical coherence tomography (OCT) to the prevention of myocardial infarction and early identification of osteoarthritis is discussed. Myocardial infarction or a heart attack is the leading cause of death worldwide. It results from an acute loss of blood flow to a region of the heart resulting in death to that heart tissue. Most heart attacks are caused by small, thin walled lipid filled plaques which can not be detected by currently available imaging technologies. This paper outlines some of the advances demonstrating the potential of OCT for the identification of high risk plaque. Osteoarthritis is a major cause of mobility in the industrialized world. The hallmark of the disease is a degradation of articular cartilage. As new therapeutics have been shown to be effective in animal models, there effectiveness in humans remains unclear as there is no effective method for accurate monitoring changes in cartilage. In the second part of this manuscript, the effectiveness of OCT for monitoring articular cartilage is described.

Li, Xing D.; Stamper, Debra L.; Patel, Nirlep A.; Saunders, Kathleen; Plummer, Sam; Schenck, John; Rogowska, Ika; Fujimoto, James G.; Brezinski, Mark E.

2002-07-01

227

Improving the Prevention of Cardiovascular Disease in Primary Health Care: The Model for Prevention Study Protocol  

PubMed Central

Background Cardiovascular disease (CVD) is the leading cause of death globally, and accounted for nearly 31% of all deaths in Australia in 2011. The primary health care sector is at the frontline for addressing CVD, however, an evidence-to-practice gap exists in CVD risk assessment and management. General practice plays a key role in CVD risk assessment and management, but this sector cannot provide ongoing lifestyle change support in isolation. Community-based lifestyle modification services and programs provided outside the general practice setting have a key role in supporting and sustaining health behavior change. Fostering linkages between the health sector and community-based lifestyle services, and creating sustainable systems that support these sectors is important. Objective The objective of the study Model for Prevention (MoFoP) is to take a case study approach to examine a CVD risk reduction intervention in primary health care, with the aim of identifying the key elements required for an effective and sustainable approach to coordinate CVD risk reduction across the health and community sectors. These elements will be used to consider a new systems-based model for the prevention of CVD that informs future practice. Methods The MoFoP study will use a mixed methods approach, comprising two complementary research elements: (1) a case study, and (2) a pre/post quasi-experimental design. The case study will consider the organizations and systems involved in a CVD risk reduction intervention as a single case. The pre/post experimental design will be used for HeartLink, the intervention being tested, where a single cohort of patients between 45 and 74 years of age (or between 35 and 74 years of age if Aboriginal or Torres Strait Islander) considered to be at high risk for a CVD event will be recruited through general practice, provided with enhanced usual care and additional health behavior change support. A range of quantitative and qualitative data will be collected. This will include individual health and well being data collected at baseline and again at 12 months for HeartLink participants, and systems related data collected over the period of the intervention to inform the case study. Results The intervention is currently underway, with results expected in late 2015. Conclusions Gaining a better understanding of CVD prevention in primary health care requires a research approach that can capture and express its complexity. The MoFoP study aims to identify the key elements for effective CVD prevention across the health and community sectors, and to develop a model to better inform policy and practice in this key health priority area for Australia. PMID:25008232

Davey, Rachel C; Cochrane, Thomas; Williams, Lauren T; Clancy, Tanya

2014-01-01

228

Modelling and disentangling physiological mechanisms: linear and nonlinear identification techniques for analysis of cardiovascular regulation  

PubMed Central

Cardiovascular (CV) regulation is the result of a number of very complex control interactions. As computational power increases and new methods for collecting experimental data emerge, the potential for exploring these interactions through modelling increases as does the potential for clinical application of such models. Understanding these interactions requires the application of a diverse set of modelling techniques. Several recent mathematical modelling techniques will be described in this review paper. Starting from Granger's causality, the problem of closed-loop identification is recalled. The main aspects of linear identification and of grey-box modelling tailored to CV regulation analysis are summarized as well as basic concepts and trends for nonlinear extensions. Sensitivity analysis is presented and discussed as a potent tool for model validation and refinement. The integration of methods and models is fostered for a further physiological comprehension and for the development of more potent and robust diagnostic tools. PMID:19324714

Batzel, Jerry; Baselli, Giuseppe; Mukkamala, Ramakrishna; Chon, Ki H

2009-01-01

229

Activation of the central histaminergic system mediates arachidonic-acid-induced cardiovascular effects.  

PubMed

The aim of this study was to explain the involvement of the central histaminergic system in arachidonic acid (AA)-induced cardiovascular effects in normotensive rats using hemodynamic, immunohistochemistry, and microdialysis studies. Intracerebroventricularly (i.c.v.) administered AA (0.25, 0.5, and 1.0 ?mol) induced dose- and time-dependent increases in mean arterial pressure and decreased heart rate in conscious normotensive Sprague-Dawley rats. Central injection of AA (0.5 ?mol) also increased posterior hypothalamic extracellular histamine levels and produced strong COX-1 but not COX-2 immunoreactivity in the posterior hypothalamus of rats. Moreover, the cardiovascular effects and COX-1 immunoreactivity in the posterior hypothalamus induced by AA (0.5 ?mol; i.c.v.) were almost completely blocked by the H2 receptor antagonist ranitidine (50 and 100 nmol; i.c.v.) and partially blocked by the H1 receptor blocker chlorpheniramine (100 nmol; i.c.v.) and the H3-H4 receptor antagonist thioperamide (50 and 100 nmol; i.c.v.). In conclusion, these results indicate that centrally administered AA induces pressor and bradycardic responses in conscious rats. Moreover, we suggest that AA may activate histaminergic neurons and increase extracellular histamine levels, particularly in the posterior hypothalamus. Acting as a neurotransmitter, histamine is potentially involved in AA-induced cardiovascular effects under normotensive conditions. PMID:25065747

Altinbas, Burcin; Topuz, Bora Burak; ?lhan, Tuncay; Yilmaz, Mustafa Sertac; Erdost, Hatice; Yalcin, Murat

2014-08-01

230

Systemic glucocorticoid therapy: a review of its metabolic and cardiovascular adverse events.  

PubMed

The prevalence of use of long-term systemic glucocorticoid therapy in the general adult population is 1 %. This figure increases to up to 3 % in elderly women. Metabolic (i.e. diabetes mellitus, dyslipidemia, weight gain, lipodystrophy) and cardiovascular (i.e. hypertension, cardiovascular events) adverse events are commonly observed in these patients and can be life threatening. Paradoxically, there is very few data on some of these adverse events and many of the available studies remain inconclusive. Incidence of and risk factors for dyslipidemia, weight gain and lipodystrophy are poorly defined. The optimal treatment plan for patients diagnosed with glucocorticoid-induced diabetes or hypertension is undetermined. Finally, there is no medical consensus on the best strategies for the prevention and detection of these complications. However, certain of these questions can be answered by looking at available data on patients with endogenous hypercortisolism (i.e. Cushing's syndrome). This article reviews the pathophysiology, incidence, risk factors, screening, and treatment of glucocorticoid-induced weight gain, lipodystrophy, diabetes, dyslipidemia, hypertension, and cardiovascular events. It also focuses on the possible prevention of these adverse events by targeting the glucocorticoid receptor using selective glucocorticoid receptor modulators. PMID:25204470

Fardet, Laurence; Fève, Bruno

2014-10-01

231

New aspects of the interactions between the cardiovascular nitric oxide system and natriuretic peptides.  

PubMed

Arterial blood pressure is regulated by a variety of endocrine, autocrine and neuronal systems. Natriuretic peptides and nitric oxide are important factors that exert synergistic vascular and cardiac actions and their activities are closely linked. The existence of a novel signal transduction mechanism involved in activation of nitric oxide synthase via natriuretic peptides is currently being explored. Since several cardiovascular disorders are associated with dysfunction of natriuretic peptides activity, selective modulation of the natriuretic peptides pathway represents an important therapeutic target. This review article highlights the current findings on cross-talk between natriuretic peptides and the nitric oxide system. PMID:21329665

Costa, María A; Arranz, Cristina T

2011-03-11

232

Cardiovascular Actions of Neurotrophins  

PubMed Central

Neurotrophins were christened in consideration of their actions on the nervous system and, for a long time, they were the exclusive interest of neuroscientists. However, more recently, this family of proteins has been shown to possess essential cardiovascular functions. During cardiovascular development, neurotrophins and their receptors are essential factors in the formation of the heart and critical regulator of vascular development. Postnatally, neurotrophins control the survival of endothelial cells, vascular smooth muscle cells, and cardiomyocytes and regulate angiogenesis and vasculogenesis, by autocrine and paracrine mechanisms. Recent studies suggest the capacity of neurotrophins, via their tropomyosin-kinase receptors, to promote therapeutic neovascularization in animal models of hindlimb ischemia. Conversely, the neurotrophin low-affinity p75NTR receptor induces apoptosis of endothelial cells and vascular smooth muscle cells and impairs angiogenesis. Finally, nerve growth factor looks particularly promising in treating microvascular complications of diabetes or reducing cardiomyocyte apoptosis in the infarcted heart. These seminal discoveries have fuelled basic and translational research and thus opened a new field of investigation in cardiovascular medicine and therapeutics. Here, we review recent progress on the molecular signaling and roles played by neurotrophins in cardiovascular development, function, and pathology, and we discuss therapeutic potential of strategies based on neurotrophin manipulation. PMID:19126759

CAPORALI, ANDREA; EMANUELI, COSTANZA

2010-01-01

233

Methods for establishing a surveillance system for cardiovascular diseases in Indian industrial populations.  

PubMed Central

OBJECTIVE: To establish a surveillance network for cardiovascular diseases (CVD) risk factors in industrial settings and estimate the risk factor burden using standardized tools. METHODS: We conducted a baseline cross-sectional survey (as part of a CVD surveillance programme) of industrial populations from 10 companies across India, situated in close proximity to medical colleges that served as study centres. The study subjects were employees (selected by age and sex stratified random sampling) and their family members. Information on behavioural, clinical and biochemical determinants was obtained through standardized methods (questionnaires, clinical measurements and biochemical analysis). Data collation and analyses were done at the national coordinating centre. FINDINGS: We report the prevalence of CVD risk factors among individuals aged 20-69 years (n = 19 973 for the questionnaire survey, n = 10 442 for biochemical investigations); mean age was 40 years. The overall prevalence of most risk factors was high, with 50.9% of men and 51.9% of women being overweight, central obesity was observed among 30.9% of men and 32.8% of women, and 40.2% of men and 14.9% of women reported current tobacco use. Self-reported prevalence of diabetes (5.3%) and hypertension (10.9%) was lower than when measured clinically and biochemically (10.1% and 27.7%, respectively). There was marked heterogeneity in the prevalence of risk factors among the study centres. CONCLUSION: There is a high burden of CVD risk factors among industrial populations across India. The surveillance system can be used as a model for replication in India as well as other developing countries. PMID:16799730

Reddy, K. S.; Prabhakaran, D.; Chaturvedi, V.; Jeemon, P.; Thankappan, K. R.; Ramakrishnan, L.; Mohan, B. V. M.; Pandav, C. S.; Ahmed, F. U.; Joshi, P. P.; Meera, R.; Amin, R. B.; Ahuja, R. C.; Das, M. S.; Jaison, T. M.

2006-01-01

234

[Diabetic neuropathies. IV. Autonomous neuropathy. Peripheral sympathetic innervation and the cardiovascular system].  

PubMed

The clinical conditions due to damage to the peripheral sympathetic nervous system during diabetic neuropathy mainly involve alterations to subcutaneous vasomotility , temperature body regulation and exudation, which may take form of hyper or hypoactivity. Gustatory exudation and local anhydrosis are described in detail as well as the connection with aggravating factors like long duration, poor balance and early onset of diabetes mellitus . Change in the relevant cardiovascular reflexes, commonly used in diagnosing diabetic neuropathy, are also analysed with a discussion of their physiopathological background and clinical significance. Finally the painless infarct, sudden death and abnormal response to hypoglycaemia, that are the common features of diabetic neuropathy, are also described. PMID:6728256

Gentile, S; Marmo, R; Costume, A; Persico, M; Bronzino, P; Contaldi, P; Stroffolini, T

1984-04-28

235

Brain-derived neurotrophic factor as a regulator of systemic and brain energy metabolism and cardiovascular health  

PubMed Central

Overweight sedentary individuals are at increased risk for cardiovascular disease, diabetes, and some neurological disorders. Beneficial effects of dietary energy restriction (DER) and exercise on brain structural plasticity and behaviors have been demonstrated in animal models of aging and acute (stroke and trauma) and chronic (Alzheimer's and Parkinson's diseases) neurological disorders. The findings described later, and evolutionary considerations, suggest brain-derived neurotrophic factor (BDNF) plays a critical role in the integration and optimization of behavioral and metabolic responses to environments with limited energy resources and intense competition. In particular, BDNF signaling mediates adaptive responses of the central, autonomic, and peripheral nervous systems from exercise and DER. In the hypothalamus, BDNF inhibits food intake and increases energy expenditure. By promoting synaptic plasticity and neurogenesis in the hippocampus, BDNF mediates exercise- and DER-induced improvements in cognitive function and neuroprotection. DER improves cardiovascular stress adaptation by a mechanism involving enhancement of brainstem cholinergic activity. Collectively, findings reviewed in this paper provide a rationale for targeting BDNF signaling for novel therapeutic interventions in a range of metabolic and neurological disorders. PMID:22548651

Rothman, Sarah M; Griffioen, Kathleen J; Wan, Ruiqian; Mattson, Mark P

2012-01-01

236

Reproduction of continuous flow left ventricular assist device experimental data by means of a hybrid cardiovascular model with baroreflex control.  

PubMed

Long-term mechanical circulatory assistance opened new problems in ventricular assist device-patient interaction, especially in relation to autonomic controls. Modeling studies, based on adequate models, could be a feasible approach of investigation. The aim of this work is the exploitation of a hybrid (hydronumerical) cardiovascular simulator to reproduce and analyze in vivo experimental data acquired during a continuous flow left ventricular assistance. The hybrid cardiovascular simulator embeds three submodels: a computational cardiovascular submodel, a computational baroreflex submodel, and a hydronumerical interface submodel. The last one comprises two impedance transformers playing the role of physical interfaces able to provide a hydraulic connection with specific cardiovascular sites (in this article, the left atrium and the ascending/descending aorta). The impedance transformers are used to connect a continuous flow pump for partial left ventricular support (Synergy Micropump, CircuLite, Inc., Saddlebrooke, NJ, USA) to the hybrid cardiovascular simulator. Data collected from five animals in physiological, pathological, and assisted conditions were reproduced using the hybrid cardiovascular simulator. All parameters useful to characterize and tune the hybrid cardiovascular simulator to a specific hemodynamic condition were extracted from experimental data. Results show that the simulator is able to reproduce animal-specific hemodynamic status both in physiological and pathological conditions, to reproduce cardiovascular left ventricular assist device (LVAD) interaction and the progressive unloading of the left ventricle for different pump speeds, and to investigate the effects of the LVAD on baroreflex activity. Results in chronic heart failure conditions show that an increment of LVAD speed from 20?000 to 22?000?rpm provokes a decrement of left ventricular flow of 35% (from 2 to 1.3?L/min). Thanks to its flexibility and modular structure, the simulator is a platform potentially useful to test different assist devices, thus providing clinicians additional information about LVAD therapy strategy. PMID:24117988

Fresiello, Libera; Zieli?ski, Krzysztof; Jacobs, Steven; Di Molfetta, Arianna; Pa?ko, Krzysztof Jakub; Bernini, Fabio; Martin, Michael; Claus, Piet; Ferrari, Gianfranco; Trivella, Maria Giovanna; Górczy?ska, Krystyna; Darowski, Marek; Meyns, Bart; Kozarski, Maciej

2014-06-01

237

Absence of Cardiovascular Manifestations in a Haploinsufficient Tgfbr1 Mouse Model  

PubMed Central

Loeys-Dietz syndrome (LDS) is an autosomal dominant arterial aneurysm disease belonging to the spectrum of transforming growth factor ? (TGF?)-associated vasculopathies. In its most typical form it is characterized by the presence of hypertelorism, bifid uvula/cleft palate and aortic aneurysm and/or arterial tortuosity. LDS is caused by heterozygous loss of function mutations in the genes encoding TGF? receptor 1 and 2 (TGFBR1 and ?2), which lead to a paradoxical increase in TGF? signaling. To address this apparent paradox and to gain more insight into the pathophysiology of aneurysmal disease, we characterized a new Tgfbr1 mouse model carrying a p.Y378* nonsense mutation. Study of the natural history in this model showed that homozygous mutant mice die during embryonic development due to defective vascularization. Heterozygous mutant mice aged 6 and 12 months were morphologically and (immuno)histochemically indistinguishable from wild-type mice. We show that the mutant allele is degraded by nonsense mediated mRNA decay, expected to result in haploinsufficiency of the mutant allele. Since this haploinsufficiency model does not result in cardiovascular malformations, it does not allow further study of the process of aneurysm formation. In addition to providing a comprehensive method for cardiovascular phenotyping in mice, the results of this study confirm that haploinsuffciency is not the underlying genetic mechanism in human LDS. PMID:24587008

Renard, Marjolijn; Trachet, Bram; Casteleyn, Christophe; Campens, Laurence; Cornillie, Pieter; Callewaert, Bert; Deleye, Steven; Vandeghinste, Bert; van Heijningen, Paula M.; Dietz, Harry; De Vos, Filip; Essers, Jeroen; Staelens, Steven; Segers, Patrick; Loeys, Bart; Coucke, Paul; De Paepe, Anne; De Backer, Julie

2014-01-01

238

[Application of computed tomography to cardiovascular system: present status and perspective].  

PubMed

In spite of major limitation in the application of computerized transmission tomography to the cardiovascular system, it has several unique advantages. The aim of this lecture is to give the recent advance and perspective of cardiac CT examination. The advantages include excellent spatial and contrast resolution and obtaining three dimensional images of the heart and the great vessels. Although CT scanning of the heart without contrast medium provides vague differentiation of the cardiac structures, with contrast medium injection it gives more precise information. Rapid sequential scanning with table movement may be useful to give tomographic images covering the whole heart. Since temporal resolution is improved with rapid sequential scanning at the fixed position, functional analysis of the cardiovascular system in a slice, for example patency of the aorto-coronary bypass graft, can be easily examined with excellent accuracy. ECG-gated scanning provides anatomical information with good temporal resolution, as well as functional values, such as left ventricular mass, left ventricular volume, left ventricular ejection fraction and cardiac output. These values obtained from cardiac CT showed a good correlation with the values from cine left ventriculography and a dye-dilution study. Thrombi or tumors in the cardiovascular lumen could be detected with CT examination. Attenuation of left ventricular wall motion, thinning of the ventricular wall and reduced regional myocardial thickness seemed to be major landmarks for computed tomographic diagnosis in ischemic heart disease. Cardiac CT examination may give the comparable information with echocardiography in this field. In the future, ultra-fast CT scanners will be developed to give the multiple section capacity for three dimensional imaging and to improve temporal resolution for cardiac functional analysis. PMID:6676384

Kozuka, T; Naito, H; Kimura, M

1983-06-01

239

The fentanyl/etomidate-anaesthetised beagle (FEAB) dog: a versatile in vivo model in cardiovascular safety research.  

PubMed

The purpose of conducting cardiovascular safety pharmacology studies is to investigate the pharmacological profiles of new molecular entities (NMEs) and provide data that can be used for optimization of a possible new drug, and help make a selection of NMEs for clinical development. An anaesthetised dog preparation has been used for more than two decades by our department to measure multiple cardiovascular and respiratory parameters and to evaluate different scientific models, leading to more in-depth evaluation of drug-induced cardiovascular effects. An anaesthetic regime developed in house (induction with lofentanil, scopolamine and succinylcholine, and maintenance with fentanyl and etomidate) gives us a preparation free of pain and stress, with minimal effects on the cardiovascular system. This anaesthetic regime had minimal influences on circulating catecholamine levels, on the baroreflex sensitivity, and on all measured basal parameters compared to conscious dogs. All parameters were stable for at least 3 h, with acceptable tolerance intervals, evaluated over 99 safety studies with 3 vehicle treatments (saline, 10% and 20% hydroxypropyl-beta-cyclodextrin). This translates into a highly sensitive model for detecting possible drug-induced effects of NMEs with different mechanisms of action such as: Ca-, Na-, I(Kr)-, I(Ks)-channel blockers, K- and Ca-channel activators, alpha1- and beta-agonists, and muscarinic antagonists. Fentanyl in combination with etomidate is a successful anaesthetic regime in humans [Stockham, R.J., Stanley, T.H., Pace, N.L., King, K., Groen, F. & Gillmor, S.T. (1987). Induction of anaesthesia with fentanyl or fentanyl plus etomidate in high-risk patients. Journal of Cardiothoracic Anesthesia. 1(1), 19-23.]. In the anaesthetised dog, QT correction factors (Van de Water correction and body temperature correction) and risk factors (total, short-term and long-term instability) have been evaluated, using this regime [Van de Water, A., Verheyen, J., Xhonneux, R. & Reneman, R. (1989). An improved method to correct the QT interval of the electrocardiogram for changes in heart rate. Journal of Pharmacological Methods, 22, 207-217.; van der Linde, H.J., Van Deuren, B., Teisman, A., Towart, R. & Gallacher, D.J. (2008). The effect of changes in core body temperature on the QT interval in beagle dogs: A previously ignored phenomenon, with a method for correction. British Journal of Pharmacology, 154, 1474-1481.; van der Linde, H.J., Van de Water, A., Loots, W., Van Deuren, B., Lu, H.R., Van Ammel, K., et al. (2005) A new method to calculate the beat-to-beat instability of QT duration in drug-induced long QT in anaesthetised dogs. Journal of Pharmacological and Toxicological Methods, 52, 168-177.]. Furthermore, this anaesthetic protocol has been used to create different scientific models (long QT, short QT) with different specific end-points (ventricular fibrillation, adrenergic- or pause-dependent TdP) and also their specific precursors: e.g. aftercontractions, phase 2 EADs, phase 3 EADs, DADs, T-wave morphology changes, T-wave alternans, R-on-T, transmural and interventricular dispersion [Gallacher, D.J., Van de Water, A., van der Linde, H.J., Hermans, A.N., Lu, H.R., Towart, R., et al. (2007). In vivo mechanisms precipitating torsade de pointes in canine model of drug-induced long QT1 syndrome. Cardiovascular Research, 76-2, 247-256.]. This paper gives a brief overview of the stability, reproducibility, sensitivity and utility of a well-validated anaesthetised dog model. PMID:19422925

Van Deuren, Bruno; Van Ammel, Karel; Somers, Yves; Cools, Frank; Straetemans, Roel; van der Linde, Henk J; Gallacher, David J

2009-01-01

240

Three-dimensional optical coherence tomography of the embryonic murine cardiovascular system  

NASA Astrophysics Data System (ADS)

Optical coherence tomography (OCT) is an emerging high-resolution real-time biomedical imaging technology that has potential as a novel investigational tool in developmental biology and functional genomics. In this study, murine embryos and embryonic hearts are visualized with an OCT system capable of 2-µm axial and 15-µm lateral resolution and with real-time acquisition rates. We present, to our knowledge, the first sets of high-resolution 2- and 3-D OCT images that reveal the internal structures of the mammalian (murine) embryo (E10.5) and embryonic (E14.5 and E17.5) cardiovascular system. Strong correlations are observed between OCT images and corresponding hematoxylin- and eosin-stained histological sections. Real-time in vivo embryonic (E10.5) heart activity is captured by spectral-domain optical coherence tomography, processed, and displayed at a continuous rate of five frames per second. With the ability to obtain not only high-resolution anatomical data but also functional information during cardiovascular development, the OCT technology has the potential to visualize and quantify changes in murine development and in congenital and induced heart disease, as well as enable a wide range of basic in vitro and in vivo research studies in functional genomics.

Luo, Wei; Marks, Daniel L.; Ralston, Tyler S.; Boppart, Stephen A.

2006-03-01

241

Classification of low systemic vascular resistance using photoplethysmogram and routine cardiovascular measurements.  

PubMed

Low systemic vascular resistance (SVR) can be a useful indicator for early diagnosis of critical pathophysiological conditions such as sepsis, and the ability to identify low SVR from simple and noninvasive physiological signals is of immense clinical value. In this study, an SVR classification system is presented to recognize the occurrence of low SVR, among a heterogenous group of patients (N = 48), based on the use of routine cardiovascular measurements and features extracted from the finger photoplethysmogram (PPG) as inputs to a quadratic discriminant classifier. An exhaustive feature search was performed to identify a near optimum feature subset. Cohen's kappa coefficient (?) was used as a performance measure to compare candidate feature sets. The classifier using the following combination of features performed best (? = 0.56, sensitivity = 96.30%, positive predictivity = 92.31%): normalized low-frequency power (LFNU) derived from PPG, ratio of low-frequency power to high-frequency power (LF/HF) of the PPG variability signal, and the ratio of mean arterial pressure to heart rate (MAP/HR). Classifiers that used either LF(NU) (? = 0.43), LF/HF (? = 0.37) or MAP/HR (? = 0.43) alone showed inferior performance. Discrimination of patients with and without low SVR can be achieved with reasonable accuracy using multiple features derived from the PPG combined with routine cardiovascular measurements. PMID:21097214

Lee, Qim Y; Chan, Gregory S H; Redmond, Stephen J; Middleton, Paul M; Steel, E; Malouf, P; Critoph, C; Flynn, G; O'Lone, E; Lovell, Nigel H

2010-01-01

242

Cardiovascular Autonomic Nervous System Function and Aerobic Capacity in Type 1 Diabetes  

PubMed Central

Impaired cardiovascular autonomic nervous system (ANS) function has been reported in type 1 diabetes (T1D) patients. ANS function, evaluated by heart rate variability (HRV), systolic blood pressure variability (SBPV), and baroreflex sensitivity (BRS), has been linked to aerobic capacity (VO2peak) in healthy subjects, but this relationship is unknown in T1D. We examined cardiovascular ANS function at rest and during function tests, and its relations to VO2peak in T1D individuals. Ten T1D patients (34?±?7?years) and 11 healthy control (CON; 31?±?6?years) age and leisure-time physical activity-matched men were studied. ANS function was recorded at rest and during active standing and handgrip. Determination of VO2peak was obtained with a graded cycle ergometer test. During ANS recordings SBPV, BRS, and resting HRV did not differ between groups, but alpha1 responses to maneuvers in detrended fluctuation analyses were smaller in T1D (active standing; 32%, handgrip; 20%, medians) than in CON (active standing; 71%, handgrip; 54%, p?cardiovascular ANS function at rest compared with CON. Resting parasympathetic cardiac activity correlated with VO2peak in CON but not in T1D. Detrended fluctuation analysis could be a sensitive detector of changes in cardiac ANS function in T1D. PMID:22973238

Hägglund, Harriet; Uusitalo, Arja; Peltonen, Juha E.; Koponen, Anne S.; Aho, Jyrki; Tiinanen, Suvi; Seppänen, Tapio; Tulppo, Mikko; Tikkanen, Heikki O.

2012-01-01

243

Hypertensive Cardiovascular and Renal Disease and Target Organ Damage: Lessons from Animal Models.  

PubMed

This brief review discusses some aspects of hypertensive damage to the kidneys and cardiovascular system. A comparison of renal and cardiac manifestations of hypertensive disease between results of clinical and experimental studies was made, with a major focus on the possible role of salt and the renin-angiotensin system (RAS) in inducing target organ damage. Thus, some degree of renal impairment is often present in patients with essential hypertension, varying from microalbuminuria to end-stage renal disease, whereas in rats with spontaneous hypertension only slight renal damage is seen in old rats with little evidence of renal failure. Since renal damage in hypertensive rats is induced when they are exposed to increased salt intake, we suggested that salt may also account for kidney injury in hypertensive patients. Similarly, cardiac damage is aggravated in hypertensive human beings and rats when given salt excess. We further presented evidence that the RAS may mediate adverse cardiac and renal effects of excessive salt intake. Finally, we also discussed some aspects of the cardiovascular physiology in the giraffe, the only mammal that in comparison with the human being has extremely high pressure at the level of the heart and kidneys but no target organ damage. PMID:22258536

Susic, Dinko; Frohlich, Edward D

2011-01-01

244

An optical multi-sensing system for detection of cardiovascular toxicity.  

PubMed

A mini-microscope-based system for multisite detection of cardiovascular toxicity was developed. The mini-microscope consisted of an image sensor and lens module extracted from an inexpensive webcam. The flipped lens module enabled cells to be magnified and monitored during testing. The portability and compactness of this system enables short-term and potential long-term experimentation inside a conventional incubator. The toxicity test results demonstrated that the normalized beating rates of cardiac muscle cells selected from multiple regions increased over time when treated with 100 nM isoprenaline. The presented system could be a promising cost-effective cell-based testing tool for discovering and screening drugs. PMID:24563288

Koo, Kyo-in; Kim, Sang Bok; Kim, Keekyoung; Oh, Jonghyun

2014-05-01

245

Modeling congestive heart failure: a control system model with state delay  

E-print Network

Modeling congestive heart failure: a control system model with state delay Jerry Batzel 1 , Susanne cardiovascular-respiratory control system is presented and applied to modeling congestive heart failure to minimize de- viations of certain state variables. The model will consider the congestive heart condition

Batzel, Jerry

246

Low-grade systemic inflammation connects aging, metabolic syndrome and cardiovascular disease.  

PubMed

Aging is associated with immunosenescence and accompanied by a chronic inflammatory state which contributes to metabolic syndrome, diabetes and their cardiovascular consequences. Risk factors for cardiovascular diseases (CVDs) and diabetes overlap, leading to the hypothesis that both share an inflammatory basis. Obesity is increased in the elderly population, and adipose tissue induces a state of systemic inflammation partially induced by adipokines. The liver plays a pivotal role in the metabolism of nutrients and exhibits alterations in the expression of genes associated with inflammation, cellular stress and fibrosis. Hepatic steatosis and its related inflammatory state (steatohepatitis) are the main hepatic complications of obesity and metabolic diseases. Aging-linked declines in expression and activity of endoplasmic reticulum molecular chaperones and folding enzymes compromise proper protein folding and the adaptive response of the unfolded protein response. These changes predispose aged individuals to CVDs. CVDs and endothelial dysfunction are characterized by a chronic alteration of inflammatory function and markers of inflammation and the innate immune response, including C-reactive protein, interleukin-6, TNF-?, and several cell adhesion molecules are linked to the occurrence of myocardial infarction and stroke in healthy elderly populations and patients with metabolic diseases. PMID:25341516

Guarner, Verónica; Rubio-Ruiz, Maria Esther

2015-01-01

247

System identification of closed-loop cardiovascular control mechanisms: diabetic autonomic neuropathy  

NASA Technical Reports Server (NTRS)

We applied cardiovascular system identification (CSI) to characterize closed-loop cardiovascular regulation in patients with diabetic autonomic neuropathy (DAN). The CSI method quantitatively analyzes beat-to-beat fluctuations in noninvasively measured heart rate, arterial blood pressure (ABP), and instantaneous lung volume (ILV) to characterize four physiological coupling mechanisms, two of which are autonomically mediated (the heart rate baroreflex and the coupling of respiration, measured in terms of ILV, to heart rate) and two of which are mechanically mediated (the coupling of ventricular contraction to the generation of the ABP wavelet and the coupling of respiration to ABP). We studied 37 control and 60 diabetic subjects who were classified as having minimal, moderate, or severe DAN on the basis of standard autonomic tests. The autonomically mediated couplings progressively decreased with increasing severity of DAN, whereas the mechanically mediated couplings were essentially unchanged. CSI identified differences between the minimal DAN and control groups, which were indistinguishable based on the standard autonomic tests. CSI may provide a powerful tool for assessing DAN.

Mukkamala, R.; Mathias, J. M.; Mullen, T. J.; Cohen, R. J.; Freeman, R.

1999-01-01

248

Landmarks in understanding the central nervous control of the cardiovascular system.  

PubMed

In this Paton Lecture I have tried to trace the key experiments that have developed ideas on how the brain regulates the cardiovascular system. It is a personal view and inevitably, owing to constraints on space and time, I have not been able to cover areas such as the nucleus tractus solitarius and cardiac vagal neurones, although I acknowledge that some may consider the story is incomplete without them. Starting with the crucial discovery of vasomotor nerves and 'vasomotor tone', the patterns of activity in sympathetic nerves which led to the important idea of central oscillating networks of neurones are described. I discuss how this knowledge has informed current controversies on the origin of vasomotor activity in presympathetic neurones in the ventral medulla, which identify intrinsic pacemaker activity or synaptic input from multiple oscillators as prime mechanisms. I present an emerging view that the role of other regions of the brain, in particular supramedullary sites, has been underplayed. These regions are pivotal for the non-uniform distribution of cardiac output that is unique to each reflex and behavioural state. I discuss the most recent evidence for 'central command' neurones that offers a plausible explanation for how these patterns of sympathetic activity are achieved. Finally, I stress the importance of these current ideas to the understanding of pathological changes in sympathetic activity in cardiovascular diseases such as hypertension or congestive heart failure. PMID:17030558

Coote, John H

2007-01-01

249

Markers of Systemic Bacterial Exposure in Periodontal Disease and Cardiovascular Disease Risk: A Systematic Review and Meta-Analysis  

Microsoft Academic Search

Background: Recent meta-analyses reported a weak associ- ation between periodontal disease (PD) on clinical examination and cardiovascular disease (CVD). Systemic bacterial expo- sure from periodontitis, which correlates poorly with the clinical examination, has been proposed as the more biologically perti- nent risk factor. The purpose of this study was to review and analyze the association between PD with elevated systemic

Indra Z. Mustapha; Sarah Debrey; Michael Oladubu; Richard Ugarte

2007-01-01

250

Flipped classroom model improves graduate student performance in cardiovascular, respiratory, and renal physiology.  

PubMed

The purpose of this study was to assess the effectiveness of a traditional lecture-based curriculum versus a modified "flipped classroom" curriculum of cardiovascular, respiratory, and renal physiology delivered to first-year graduate students. Students in both courses were provided the same notes and recorded lectures. Students in the modified flipped classroom were required to watch the prerecorded lectures before class and then attend class, where they received a quiz or homework covering material in each lecture (valued at 25% of the final grade) followed by a question and answer/problem-solving period. In the traditional curriculum, attending lectures was optional and there were no quizzes. Evaluation of effectiveness and student performance was achieved by having students in both courses take the same multiple-choice exams. Within a comparable group of graduate students, participants in the flipped course scored significantly higher (P ? 0.05) on the cardiovascular, respiratory, and weighted cumulative sections by an average of >12 percentage points. Exam averages for students in the flipped course also tended to be higher on the renal section by ?11 percentage points (P = 0.06). Based on our experience and responses obtained in blinded student surveys, we propose that the use of homework and in-class quizzes were critical motivating factors that likely contributed to the increase in student exam performance. Taken together, our findings support that the flipped classroom model is a highly effective means in which to disseminate key physiological concepts to graduate students. PMID:24292907

Tune, Johnathan D; Sturek, Michael; Basile, David P

2013-12-01

251

Designing an outcome-oriented computer decision-support system for cardiovascular ICU--a preliminary report.  

PubMed

This paper describes the conceptual framework and preliminary results of an outcome-oriented decision-support system prototype for the cardiovascular intensive care unit (CVICU). The major characteristics of this design include: (1) its problem-based approach to solving clinical problems; (2) an integrated structure with the hospital information system in terms of its data, model and knowledge bases; (3) proposed alternative modes of interaction that include monitoring and critiquing; (4) and research modules that design, manage, and analyze outcome-based clinical studies. At present, an initial prototype has been implemented on a PC as a set of modules accessible from a main menu. The structural framework of the overall system is fairly well defined but only limited quantitative, statistical and expert knowledge has been captured. The second phase of the project involves porting the prototype to a Unix workstation environment, refining and adding models to the model base, expanding its knowledge bases, reasoning capability, and testing the prototype with actual clinical cases in a real-time fashion. PMID:1812188

Lau, F; Vincent, D; Fenna, D; Goebel, R; Modry, D

1991-12-01

252

Unusual fistulas and connections in the cardiovascular system: A pictorial review  

PubMed Central

A fistula is an abnormal vascular connection leading to diversion of blood from a high resistance arterial circuit to low resistance venous circuit. Coronary artery fistulas are abnormal communications of the coronary artery with a chamber of the heart, or with any segment of systemic or pulmonary circulation, bypassing the myocardial capillaries. Other unusual fistulas include connection between aorta and the right atrium/superior vena cava, aorta and the inferior vena cava or between a coronary artery bypass graft and a cardiac vein. Abnormal connections also include origin of the coronary artery from the pulmonary artery. In this article, we review the imaging, particularly computed tomography and magnetic resonance imaging of unusual fistulas and connections involving the cardiovascular system, particularly the coronary arteries and the aorta. PMID:24876921

Ghandour, Abed; Rajiah, Prabhakar

2014-01-01

253

Influence of Space Weather on a Cardiovascular System of a Human Being During Various Solar Cycle Phases  

NASA Astrophysics Data System (ADS)

The study of relationship of dynamics of space weather parameters to changes of cardiovascular system state of a human being was carried out by data of measurements of volunteer groups in October - December 2009 and March-April, 2011 by data of Yakutsk and Tixie carried out according to the program of Russian-Ukrainian "Geliomed" project. It is shown that during a phase of minimum (2009) and growth phase (2011) of the 11-year solar activity a distinction in the response of cardiovascular system of a human being connected with the level of geomagnetic activity, latitude of residing of a human being and his/her age is observed.

Samsonov, S. N.; Manykina, V. I.; Krymsky, G. F.; Parshina, S. S.; Petrova, P. G.; Palshina, A. A.; Strekalovskaya, A. A.; Shadrina, L. P., Vishnevsky, V. V.

254

The effect of blood volume loss on cardiovascular response to lower body negative pressure using a mathematical model  

NASA Technical Reports Server (NTRS)

Different mathematical models of varying complexity have been proposed in recent years to study the cardiovascular (CV) system. However, only a few of them specifically address the response to lower body negative pressure (LBNP), a stress that can be applied in weightlessness to predict changes in orthostatic tolerance. Also, the simulated results produced by these models agree only partially with experimental observations. In contrast, the model proposed by Melchior et al., and modified by Karam et al. is a simple representation of the CV system capable of accurately reproducing observed LBNP responses up to presyncopal levels. There are significant changes in LBNP response due to a loss of blood volume and other alterations that occur in weightlessness and related one-g conditions such as bedrest. A few days of bedrest can cause up to 15% blood volume loss (BVL), with consequent decreases in both stroke volume and cardiac output, and increases in heart rate, mean arterial pressure, and total peripheral resistance. These changes are more pronounced at higher levels of LBNP. This paper presents the results of a simulation study using our CV model to examine the effect of BVL on LBNP response.

Karam, E. H.; Srinivasan, R. S.; Charles, J. B.; Fortney, S. M.

1994-01-01

255

Results of a Markov model analysis to assess the cost-effectiveness of statin therapy for the primary prevention of cardiovascular disease in Korea: The Korean Individual-Microsimulation Model for Cardiovascular Health Interventions  

Microsoft Academic Search

Background: Although hyperlipidemia is well recognized as a risk factor for cardiovascular disease (CVD), there has been no appraisal of the economic impact of statin therapy in Korea.Objective: The aim of this model analysis was to determine the cost-effectiveness of statin therapy versus no treatment for the primary prevention of CVD over a lifetime in Korea, from a health care

Hye-Young Kang; Su-Kyoung Ko; Danny Liew

2009-01-01

256

Artificial neural network models for prediction of cardiovascular autonomic dysfunction in general Chinese population  

PubMed Central

Background The present study aimed to develop an artificial neural network (ANN) based prediction model for cardiovascular autonomic (CA) dysfunction in the general population. Methods We analyzed a previous dataset based on a population sample consisted of 2,092 individuals aged 30–80 years. The prediction models were derived from an exploratory set using ANN analysis. Performances of these prediction models were evaluated in the validation set. Results Univariate analysis indicated that 14 risk factors showed statistically significant association with CA dysfunction (P?model developed using ANN analysis. The mean sensitivity, specificity, positive and negative predictive values were similar in the prediction models was 0.751, 0.665, 0.330 and 0.924, respectively. All HL statistics were less than 15.0. Conclusion ANN is an effective tool for developing prediction models with high value for predicting CA dysfunction among the general population. PMID:23902963

2013-01-01

257

The effect of progressive hypoxia on the respiratory and cardiovascular systems of the pigeon and duck  

PubMed Central

1. During the initial stages of progressive hypoxia in ducks and pigeons (Pa, O2 100 ? 60 mm Hg) there were no significant changes in heart rate, blood pressure or oxygen uptake, but respiratory frequency increased. 2. As hypoxia became more profound (Pa, O2 60 ? 30 mm Hg), there was a significant tachycardia, and blood pressure fell slightly in both animals. Respiratory frequency continued to increase in both species, and ducks were able to maintain their oxygen uptake at control levels at a lower Pa, O2 than pigeons. 3. The response to progressive hypoxia of pigeons and ducks was compared with that of the domestic fowl. The former two birds could maintain control of their cardiovascular system at a lower environmental oxygen concentration than the latter. Arterial PO2 followed a similar course in all three birds in relation to environmental oxygen content. Pigeons and ducks were therefore able to endure a lower arterial PO2 than chickens. PMID:5501049

Butler, P. J.

1970-01-01

258

A practical introduction to the hemodynamic analysis of the cardiovascular system with 4D Flow MRI.  

PubMed

The 4D Flow MRI technique provides a three-dimensional representation of blood flow over time, making it possible to evaluate the hemodynamics of the cardiovascular system both qualitatively and quantitatively. In this article, we describe the application of the 4D Flow technique in a 3T scanner; in addition to the technical parameters, we discuss the advantages and limitations of the technique and its possible clinical applications. We used 4D Flow MRI to study different body areas (chest, abdomen, neck, and head) in 10 volunteers. We obtained 3D representations of the patterns of flow and quantitative hemodynamic measurements. The technique makes it possible to evaluate the pattern of blood flow in large and midsize vessels without the need for exogenous contrast agents. PMID:25447368

Pineda Zapata, J A; Delgado de Bedout, J A; Rascovsky Ramírez, S; Bustamante, C; Mesa, S; Calvo Betancur, V D

2014-01-01

259

[Main ways of improvements of the systems of medical rehabilitation of military servicemen after cardiovascular surgery].  

PubMed

For better improvement of medical rehabilitation referred to effective restoration of functional status of servicemen after cardiovascular surgery it is necessary to introduce standards of medical rehabilitation at all stages of rehabilitation, syndrome-pathologic principle of grouping patients, multidisciplinary organisation of medical activity: cardiologist-physician, specialist of functional diagnostics, specialist of physical therapy, psychotherapist, physical therapeutic, surgeon and specialist of professional rehabilitation. Basic ways of improvement of the system of rehabilitation were organisational technologies of interaction during early and late stages of rehabilitation and persistent control of quality and effectiveness of rehabilitation. Optimization of organisation of late stage of hospitalisation allowed to reduce the average time of rehabilitation to 33,3% and at the same time to improve effectiveness of rehabilitation. PMID:25546953

Iudin, V E; Klimko, V V; Shkarupa, O F; Guzenko, I E

2014-08-01

260

FRONTIERS IN CARDIOVASCULAR  

E-print Network

of Heart Failure: Sex Differences Vera Regitz-Zagrosek, MD, PhD Center for Cardiovascular Research, CharitéFRONTIERS IN CARDIOVASCULAR SCIENCE SPON S ORED BY LOCATION/TIME Li Ka Shing Center for Learning at 11:45 a.m. TUESDAY, JANUARY 10, 2012 Learning the Health System and CV Disease: a Possibility

Ford, James

261

Applied cardiovascular physiology  

Microsoft Academic Search

Physical exercise involves complex coordinated responses involving the locomotor, respiratory and cardiovascular systems. The first cardiovascular changes are initiated by a central drive, which starts either in anticipation of, or at the start of, exercise and leads to a decrease in cardiac vagal activity and an increase in sympathetic activity. Though an increase in heart rate may be the first

Roger Hainsworth

2004-01-01

262

Fabrication of polyurethane and polyurethane based composite fibres by the electrospinning technique for soft tissue engineering of cardiovascular system.  

PubMed

Electrospinning is a unique technique, which provides forming of polymeric scaffolds for soft tissue engineering, which include tissue scaffolds for soft tissues of the cardiovascular system. Such artificial soft tissues of the cardiovascular system may possess mechanical properties comparable to native vascular tissues. Electrospinning technique gives the opportunity to form fibres with nm- to ?m-scale in diameter. The arrangement of obtained fibres and their surface determine the biocompatibility of the scaffolds. Polyurethanes (PUs) are being commonly used as a prosthesis of cardiovascular soft tissues due to their excellent biocompatibility, non-toxicity, elasticity and mechanical properties. PUs also possess fine spinning properties. The combination of a variety of PU properties with an electrospinning technique, conducted at the well tailored conditions, gives unlimited possibilities of forming novel polyurethane materials suitable for soft tissue scaffolds applied in cardiovascular tissue engineering. This paper can help researches to gain more widespread and deeper understanding of designing electrospinable PU materials, which may be used as cardiovascular soft tissue scaffolds. In this paper we focus on reagents used in PU synthesis designed to increase PU biocompatibility (polyols) and biodegradability (isocyanates). We also describe suggested surface modifications of electrospun PUs, and the direct influence of surface wettability on providing enhanced biocompatibility of scaffolds. We indicate a great influence of electrospinning parameters (voltage, flow rate, working distance) and used solvents (mostly DMF, THF and HFIP) on fibre alignment and diameter - what impacts the biocompatibility and hemocompatibility of such electrospun PU scaffolds. Moreover, we present PU modifications with natural polymers with novel approach applied in electrospinning of PU scaffolds. This work may contribute with further developing of novel electrospun PUs, which may be applied as soft tissue scaffolds of the cardiovascular system. PMID:25491973

Kucinska-Lipka, J; Gubanska, I; Janik, H; Sienkiewicz, M

2015-01-01

263

Overexpression of a membrane protein, neuropilin, in chimeric mice causes anomalies in the cardiovascular system, nervous system and limbs.  

PubMed

Neuropilin is a type 1 membrane protein, which is highly conserved among Xenopus frog, chicken and mouse. The extracellular part of the neuropilin protein is composed of three unique domains, each of which is thought to be involved in molecular and/or cellular interactions. In mice, neuropilin is expressed in the cardiovascular system, nervous system and limbs at particular developmental stages. To clarify the roles of neuropilin in morphogenesis in vivo, we generated mouse embryonic stem (ES) cell clones that constitutively expressed exogenous neuropilin, then produced chimeras using these ES cell clones. The chimeras overexpressed neuropilin and were embryonic lethal. The chimeric embryos exhibited several morphological abnormalities; excess capillaries and blood vessels, dilation of blood vessels, malformed hearts, ectopic sprouting and defasciculation of nerve fibers, and extra digits. All of these abnormalities occurred in the organs in which neuropilin is expressed in normal development. The variety of abnormalities occurring in these chimeric embryos suggested diverse functions of neuropilin in embryonic morphogenesis, which may be ascribed to multiple interaction domains identified in the molecule. Correct spatiotemporal expression of neuropilin seems to be essential for normal development of the cardiovascular system, nervous system and limbs. PMID:8575331

Kitsukawa, T; Shimono, A; Kawakami, A; Kondoh, H; Fujisawa, H

1995-12-01

264

Tenascin-C and mechanotransduction in the development and diseases of cardiovascular system  

PubMed Central

Living tissue is composed of cells and extracellular matrix (ECM). In the heart and blood vessels, which are constantly subjected to mechanical stress, ECM molecules form well-developed fibrous frameworks to maintain tissue structure. ECM is also important for biological signaling, which influences various cellular functions in embryonic development, and physiological/pathological responses to extrinsic stimuli. Among ECM molecules, increased attention has been focused on matricellular proteins. Matricellular proteins are a growing group of non-structural ECM proteins highly up-regulated at active tissue remodeling, serving as biological mediators. Tenascin-C (TNC) is a typical matricellular protein, which is highly expressed during embryonic development, wound healing, inflammation, and cancer invasion. The expression is tightly regulated, dependent on the microenvironment, including various growth factors, cytokines, and mechanical stress. In the heart, TNC appears in a spatiotemporal-restricted manner during early stages of development, sparsely detected in normal adults, but transiently re-expressed at restricted sites associated with tissue injury and inflammation. Similarly, in the vascular system, TNC is strongly up-regulated during embryonic development and under pathological conditions with an increase in hemodynamic stress. Despite its intriguing expression pattern, cardiovascular system develops normally in TNC knockout mice. However, deletion of TNC causes acute aortic dissection (AAD) under strong mechanical and humoral stress. Accumulating reports suggest that TNC may modulate the inflammatory response and contribute to elasticity of the tissue, so that it may protect cardiovascular tissue from destructive stress responses. TNC may be a key molecule to control cellular activity during development, adaptation, or pathological tissue remodeling. PMID:25120494

Imanaka-Yoshida, Kyoko; Aoki, Hiroki

2014-01-01

265

Differential Distribution of Bradykinin B(2) Receptors in the Rat and Human Cardiovascular System.  

PubMed

-Bradykinin, a major vasodilator peptide, plays an important role in the local regulation of blood pressure, blood flow, and vascular permeability; however, the cellular distribution of the major bradykinin B(2) receptor in the cardiovascular system is not precisely known. Immunoblot analysis with an anti-peptide antibody to the bradykinin B(2) receptor or chemical cross-linkage with [(125)I]Tyr(0)-bradykinin revealed a band of 69+/-3 kDa at varying intensity in the homogenates of the endothelium and tunica media of the rat aorta and endocardium. Immunostaining showed that the B(2) receptor is abundant in the endothelial linings of the aorta, other elastic arteries, muscular arteries, capillaries, venules, and large veins, where it localizes preferentially to the luminal face of the endothelial cells. In marked contrast, small arterioles (ie, the principal blood-pressure regulating vessels) of the mesenterium, heart, urinary bladder, brain, salivary gland, and kidney had a different staining pattern in which B(2) receptor was prominent in the perivascular smooth muscle cells of the tunica media. A similar distribution pattern was found in mouse as well as in human tissues, indicating that the particular distribution pattern of the B(2) receptor in arterioles is not a species-specific phenomenon. During development, the distribution of B(2) receptor in the heart changes; for example, in the heart of newborn rats, the B(2) receptor was abundant in the myocardium, whereas in the adult heart, the receptor was present in the endocardium of atria, atrioventricular valves, and ventricles but not in the myocardium. Thus, B(2) receptors are localized differentially in different parts of the cardiovascular system: the arterioles have smooth muscle-localized B(2) receptors, and large elastic vessels have endothelium-localized receptors. PMID:11208765

Figueroa, Carlos D.; Marchant, Alejandra; Novoa, Ulises; Förstermann, Ulrich; Jarnagin, Kurt; Schölkens, Bernward; Müller-Esterl, Werner

2001-01-01

266

A cardiovascular disease policy model that predicts life expectancy taking into account socioeconomic deprivation  

PubMed Central

Objectives A policy model is a model that can evaluate the effectiveness and cost-effectiveness of interventions and inform policy decisions. In this study, we introduce a cardiovascular disease (CVD) policy model which can be used to model remaining life expectancy including a measure of socioeconomic deprivation as an independent risk factor for CVD. Design A state transition model was developed using the Scottish Heart Health Extended Cohort (SHHEC) linked to Scottish morbidity and death records. Individuals start in a CVD-free state and can transit to three CVD event states plus a non-CVD death state. Individuals who have a non-fatal first event are then followed up until death. Taking a competing risk approach, the cause-specific hazards of a first event are modelled using parametric survival analysis. Survival following a first non-fatal event is also modelled parametrically. We assessed discrimination, validation and calibration of our model. Results Our model achieved a good level of discrimination in each component (c-statistics for men (women)—non-fatal coronary heart disease (CHD): 0.70 (0.74), non-fatal cerebrovascular disease (CBVD): 0.73 (0.76), fatal CVD: 0.77 (0.80), fatal non-CVD: 0.74 (0.72), survival after non-fatal CHD: 0.68 (0.67) and survival after non-fatal CBVD: 0.65 (0.66)). In general, our model predictions were comparable with observed event rates for a Scottish randomised statin trial population which has an overlapping follow-up period with SHHEC. After applying a calibration factor, our predictions of life expectancy closely match those published in recent national life tables. Conclusions Our model can be used to estimate the impact of primary prevention interventions on life expectancy and can assess the impact of interventions on inequalities. PMID:25324535

Lewsey, J D; Lawson, K D; Ford, I; Fox, K A A; Ritchie, L D; Tunstall-Pedoe, H; Watt, G C M; Woodward, M; Kent, S; Neilson, M; Briggs, A H

2015-01-01

267

SUBCHRONIC PULMONARY PATHOLOGY, IRON-OVERLOAD AND TRANSCRIPTIONAL ACTIVITY AFTER LIBBY AMPHIBOLE EXPOSURE IN RAT MODELS OF CARDIOVASCULAR DISEASE  

EPA Science Inventory

Background: Surface-available iron (Fe) is proposed to contribute to asbestos-induced toxicity through the production of reactive oxygen species.Objective: Our goal was to evaluate the hypothesis that rat models of cardiovascular disease with coexistent Fe overload would be incre...

268

Abstract--Normal aging is associated with changes in the cardiovascular system and more specifically in cerebral  

E-print Network

, with different studies reporting intact and reduced reactivity [4]-[6]. Finally, sex-dependent, age- relatedAbstract-- Normal aging is associated with changes in the cardiovascular system and more specifically in cerebral circulation. Sex-dependent changes in cerebrovascular CO2 reactivity, which may

Mitsis, Georgios

269

Multifractality, sample entropy, and wavelet analyses for age-related changes in the peripheral cardiovascular system: Preliminary results  

E-print Network

of aging on the peripheral cardiovascular system. Laser Doppler flowmetry LDF signals, reflecting. © 2008 American Association of Physi- cists in Medicine. DOI: 10.1118/1.2831909 Key words: laser Doppler signals and cardiac interbeat interval dynamics show less variability with aging see for example Refs. 1

Chapeau-Blondeau, François

270

Autonomic Nervous System Activity and Decline as Prognostic Indicators of Cardiovascular and Cerebrovascular Events: The ‘PROOF’ Study  

Microsoft Academic Search

Background: Transversal studies have underlined the association between the decline in autonomic nervous system (ANS) activity and all-cause mortality. However, the predictive value of ANS has never been prospectively assessed in a general population-based cohort. Method: The PROOF (PROgnostic indicator OF cardiovascular and cerebrovascular events) cohort study was designed to prospectively assess the predictive value of ANS activity level in

Jean-Claude Barthélémy; Vincent Pichot; Virginie Dauphinot; Sébastien Celle; Bernard Laurent; Arnauld Garcin; Delphine Maudoux; Judith Kerleroux; Jean-René Lacour; Michel Kossovsky; Jean-Michel Gaspoz; Frédéric Roche

2007-01-01

271

First-Year Medical Students' Conceptual Understanding of and Resistance to Conceptual Change Concerning the Central Cardiovascular System  

ERIC Educational Resources Information Center

Medical students often have initial understanding concerning medical domains, such as the central cardiovascular system (CCVS), when they enter the study programme. These notions may to some extent be in conflict with scientific understanding, which can be seen as a challenge for medical teaching. Hence, the purpose of this study was to analyse…

Mikkila-Erdmann, Mirjamaija; Sodervik, Ilona; Vilppu, Henna; Kaapa, Pekka; Olkinuora, Erkki

2012-01-01

272

Renal and Cardiovascular Responses to Water Immersion in Essential Hypertension: Is There a Role for the Opioidergic System?  

Microsoft Academic Search

Our study aimed at elucidating the effects of acute central hypervolemia induced by water immersion (WI) on renal hemodynamics, hormonal responses and on cardiovascular control in hypertensive patients, as well as at evaluating the possible role of the opioidergic system (OS) in determining these effects. Thirteen essential hypertensives were studied for 2 h before and for 2 h during WI.

Paolo Coruzzi; Gianfranco Parati; Lorenzo Brambilla; Valerio Brambilla; Massimo Gualerzi; Almerico Novarini; Giuseppe Mancia; Paolo Castiglioni; Marco Di Rienzo

2003-01-01

273

Periodontal disease as a risk factor for cardiovascular disease: Suggestion of a further link in systemic lupus erythematosus  

Microsoft Academic Search

Cardiovascular disease (CVD) is a major cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Due to either infection or disease activity, elevated levels of inflammatory markers and up-regulation of the autoimmune process can contribute to the development of atherosclerosis in SLE patients. Periodontal diseases are among the most prevalent chronic infections in humans and are characterized

Larissa Pessoa; Virgilio Galvão; Leopoldo Santos-Neto

2011-01-01

274

The degeneration of biological cardiovascular prostheses under pro-calcific metabolic conditions in a small animal model.  

PubMed

In order to allow for a comparative evaluation of the in vivo degeneration of biological and tissue-engineered heart valves and vascular grafts, a small animal model of accelerated cardiovascular calcification is desired. Wistar rats (n = 102; 6 groups) were fed ad libitum with regular chow and 5 different regimens of pro-calcific diet supplemented with combinations of vitamin D (VD), cholesterol (CH) and dicalcium phosphate (PH). Moreover, cryopreserved (n = 7) or detergent-decellularized rat aortic conduit grafts (n = 6) were infrarenally implanted in Wistar rats under severely pro-calcific conditions. The follow-up lasted up to 12 weeks. High-dose application of VD (300,000 IU/kg), CH (2%) and PH (1.5%) resulted in elevated serum calcium and cholesterol levels as well as LDL/HDL ratio. It increased the tissue MMP activity visualized by in situ zymography and caused significantly aggravated calcification of the native aortic valve as well as the aortic wall as assessed by histology and micro-computed tomography. (Immuno)histology and quantitative real-time PCR revealed chondro-osteogenic cell transformation, lipid deposition, nitrosative stress and low-level inflammation to be involved in the formation of calcific lesions. Despite pro-calcific in vivo conditions, decellularization significantly reduced calcification, inflammation and intimal hyperplasia in aortic conduit implants. A well balanced dietary trigger for pathologic metabolic conditions may represent an appropriate mid-term treatment to induce calcifying degeneration of aortic valves as well as vascular structures in the systemic circulation in rats. With respect to experimental investigation focusing on calcifying degeneration of native or prosthetic tissue, this regimen may serve as a valuable tool with a rapid onset and multi-facetted character of cardiovascular degeneration. PMID:24917029

Assmann, Alexander; Zwirnmann, Kai; Heidelberg, Friederike; Schiffer, Franziska; Horstkötter, Kim; Munakata, Hiroshi; Gremse, Felix; Barth, Mareike; Lichtenberg, Artur; Akhyari, Payam

2014-08-01

275

A System-Level Investigation into the Mechanisms of Chinese Traditional Medicine: Compound Danshen Formula for Cardiovascular Disease Treatment  

PubMed Central

Compound Danshen Formula (CDF) is a widely used Traditional Chinese Medicine (TCM) which has been extensively applied in clinical treatment of cardiovascular diseases (CVDs). However, the underlying mechanism of clinical administrating CDF on CVDs is not clear. In this study, the pharmacological effect of CDF on CVDs was analyzed at a systemic point of view. A systems-pharmacological model based on chemical, chemogenomics and pharmacological data is developed via network reconstruction approach. By using this model, we performed a high-throughput in silico screen and obtained a group of compounds from CDF which possess desirable pharmacodynamical and pharmacological characteristics. These compounds and the corresponding protein targets are further used to search against biological databases, such as the compound-target associations, compound-pathway connections and disease-target interactions for reconstructing the biologically meaningful networks for a TCM formula. This study not only made a contribution to a better understanding of the mechanisms of CDF, but also proposed a strategy to develop novel TCM candidates at a network pharmacology level. PMID:22962593

Li, Xiuxiu; Xu, Xue; Wang, Jinan; Yu, Hua; Wang, Xia; Yang, Hongjun; Xu, Haiyu; Tang, Shihuan; Li, Yan; Yang, Ling; Huang, Luqi; Wang, Yonghua; Yang, Shengli

2012-01-01

276

The risk of cardiovascular disease in systemic sclerosis: a population-based cohort study  

PubMed Central

Objectives To evaluate the risk of incident myocardial infarction (MI), stroke and peripheral vascular disease (PVD) in individuals with systemic sclerosis (SSc) in a general population context. Methods We conducted a cohort study using a UK primary care database containing records from 1986 to 2011. SSc diagnoses, outcomes and cardiovascular risk factors were identified from electronic medical records. We conducted two cohort analyses: (1) MI and stroke, and (2) PVD, excluding individuals with prevalent disease at baseline for each analysis. We estimated HRs comparing SSc with age-, sex- and entry time-matched comparison cohorts, adjusting for potential cardiovascular risk factors. Results Among 865 individuals with SSc (85.8% women, mean age 58.7 years), the incidence rates (IRs) of MI and stroke were 4.4 and 4.8 per 1000 person-years (PY), versus 2.5 and 2.5 per 1000 PY in the comparison cohort. The corresponding adjusted HRs were 1.80 (95% CI 1.07 to 3.05) for MI and 2.61 (95% CI 1.54 to 4.44) for stroke. Among 858 individuals with SSc (85.3% female, mean age 58.9 years), the IR of PVD was 7.6 per 1000 PY versus 1.9 per 1000 PY in the comparison cohort, with an adjusted HR of 4.35 (95% CI 2.74 to 6.93). Conclusions These findings provide the first general population-based evidence that SSc is associated with an increased risk of developing MI, stroke and PVD. Further insight into disease mechanisms, as well as how disease subtype, organ involvement and medication use may alter these increased risks, is needed. PMID:22904260

Man, Ada; Zhu, Yanyan; Zhang, Yuqing; Dubreuil, Maureen; Rho, Young Hee; Peloquin, Christine; Simms, Robert W; Choi, Hyon K

2015-01-01

277

Adrenergic control of the cardiovascular system in the turtle Trachemys scripta.  

PubMed

Freshwater turtles, Trachemys scripta, like all non-crocodilian reptiles, are able to shunt blood between the pulmonary and systemic circulations owing to their undivided ventricle. The prevailing hypothesis is that the ratio of pulmonary and systemic resistances is the primary determinant of cardiac shunting in turtles. In the present study, we have examined the adrenergic influences on vascular resistances in the pulmonary and systemic circulations and the associated effects on cardiac shunts in turtles. To achieve this objective, systemic blood flow and pressures and pulmonary blood flow and pressures were measured simultaneously in anaesthetised turtles during bolus injections of alpha- and beta-adrenergic agonists and antagonists. Total cardiac output, systemic vascular resistance, pulmonary vascular resistance, heart rate and cardiac stroke volume were derived from these measurements. Anaesthetised turtles showed cardiovascular characteristics that were similar to those of non-apnoeic non-anaesthetised turtles, because anaesthesia blocked the cholinergically mediated constriction of the pulmonary artery that is normally associated with apnoea. As a result, the anaesthetised turtles exhibited a large net left-to-right shunt, and the adrenergic responses could be observed without confounding changes resulting from apnoea. Potent alpha-adrenergic vasoconstriction and weaker beta-adrenergic vasodilation were discovered in the systemic circulation. Modest beta-adrenergic vasodilation and possible weak alpha-adrenergic vasodilation were discovered in the pulmonary circulation. This adrenergically mediated vasoactivity produced the largest range of cardiac shunts observed so far in turtles. Regression analysis revealed that 97% of the variability in the cardiac shunts could be accounted for by the ratio of the pulmonary and systemic resistances. Thus, we conclude that, independent of whether the pulmonary vascular resistance is modulated (as during apnoea) or the systemic resistance is modulated with adrenergic mechanisms (as shown here), the consequences on the cardiac shunt patterns are the same because they are determined primarily by the ratios of the pulmonary and systemic resistance. PMID:12324543

Overgaard, Johannes; Stecyk, Jonathan A W; Farrell, Anthony P; Wang, Tobias

2002-11-01

278

Postdoctoral Fellow Neural Cardiovascular Physiology  

E-print Network

Postdoctoral Fellow Neural Cardiovascular Physiology Job Description A postdoctoral position and physiological roles of new components of the renin-angiotensin system in the regulation of cardiovascular with a strong background in molecular biology and cardiovascular physiology. Expertise in sympathetic nerve

Collett Jr., Jeffrey L.

279

CARDIOVASCULAR DISEASES AND PERIODONTAL TREATMENT  

Microsoft Academic Search

Safe and effective periodontal treatment requires knowledge and understanding of diseases specifically those affecting the cardiovascular system in order to institute necessary modifications to periodontal therapy accordingly. Considering the high incidence of periodontal diseases in elderly individuals, the periodontist must be prepared to provide periodontal therapeutic support for an increasing number of cardiovascular patients. In this review, common cardiovascular disorders

E. J. Sauvetre; C. V. Diji

280

Ghrelin and Cardiovascular Diseases  

PubMed Central

Ghrelin, a newly discovered bioactive peptide, is a natural endogenous ligand of the growth hormone (GH) secretagogue receptor and initially identified as a strong stimulant for the release of GH. Subsequent research has shown that ghrelin and its various receptors are ubiquitous in many other organs and tissues. Moreover, they participate in the regulation of appetite, energy, bodyweight, metabolism of glucose and fat, as well as modulation of gastrointestinal, cardiovascular, pulmonary, immune functions and cell proliferation/apoptosis. Increasing evidence has demonstrated that ghrelin has a close relationship with cardiovascular system. Ghrelin and its receptors are widely distributed in cardiovascular tissues, and there is no doubt that the effects of ghrelin in the cardiovascular system are mediated not only via its growth-hormone-releasing effect but also by its direct effects on the heart. Exogenous administration of ghrelin can dilate peripheral blood vessels, constrict coronary artery, improve endothelial function, as well as inhibit myocardial cell apoptosis. So, ghrelin may have cardiovascular protective effect, including lowering of blood pressure, regulation of atherosclerosis, and protection from ischemia/reperfusion injury as well as improving the prognosis of myocardial infarction and heart failure. Some of these new functions of ghrelin may provide new potential therapeutic opportunities for ghrelin in cardiovascular medicine. In this paper, we will review the existing evidence for cardiovascular effects of ghrelin, including the cardiovascular function, the variations in ghrelin plasma levels in pathophysiologicalogical conditions, the possible protective mechanisms of ghrelin, as well as its future potential therapeutic roles. PMID:21286280

Zhang, Gaigai; Yin, Xinhua; Qi, Yongfen; Pendyala, Lakshmana; Chen, Jack; Hou, Dongming; Tang, Chaoshu

2010-01-01

281

Polyphenols: Benefits to the Cardiovascular System in Health and in Aging  

PubMed Central

Numerous studies have demonstrated the importance of naturally occurring dietary polyphenols in promoting cardiovascular health and emphasized the significant role these compounds play in limiting the effects of cellular aging. Polyphenols such as resveratrol, epigallocatechin gallate (EGCG), and curcumin have been acknowledged for having beneficial effects on cardiovascular health, while some have also been shown to be protective in aging. This review highlights the literature surrounding this topic on the prominently studied and documented polyphenols as pertaining to cardiovascular health and aging. PMID:24077237

Khurana, Sandhya; Venkataraman, Krishnan; Hollingsworth, Amanda; Piche, Matthew; Tai, T. C.

2013-01-01

282

Cardiovascular Deconditioning  

NASA Technical Reports Server (NTRS)

Spaceflight causes adaptive changes in cardiovascular function that may deleteriously affect crew health and safety. Over the last three decades, symptoms of cardiovascular changes have ranged from postflight orthostatic tachycardia and decreased exercise capacity to serious cardiac rhythm disturbances during extravehicular activities (EVA). The most documented symptom of cardiovascular dysfunction, postflight orthostatic intolerance, has affected a significant percentage of U.S. Space Shuttle astronauts. Problems of cardiovascular dysfunction associated with spaceflight are a concern to NASA. This has been particularly true during Shuttle flights where the primary concern is the crew's physical health, including the pilot's ability to land the Orbiter, and the crew's ability to quickly egress and move to safety should a dangerous condition arise. The study of astronauts during Shuttle activities is inherently more difficult than most human research. Consequently, sample sizes have been small and results have lacked consistency. Before the Extended Duration Orbiter Medical Project (EDOMP), there was a lack of normative data on changes in cardiovascular parameters during and after spaceflight. The EDOMP for the first time allowed studies on a large enough number of subjects to overcome some of these problems. There were three primary goals of the Cardiovascular EDOMP studies. The first was to establish, through descriptive studies, a normative data base of cardiovascular changes attributable to spaceflight. The second goal was to determine mechanisms of cardiovascular changes resulting from spaceflight (particularly orthostatic hypotension and cardiac rhythm disturbances). The third was to evaluate possible countermeasures. The Cardiovascular EDOMP studies involved parallel descriptive, mechanistic, and countermeasure evaluations.

Charles, John B.; Fritsch-Yelle, Janice M.; Whitson, Peggy A.; Wood, Margie L.; Brown, Troy E.; Fortner, G. William

1999-01-01

283

SUSCEPTIBILITY TO OZONE-INDUCED INJURY AND ANTIOXIDANT COMPENSATION IN RAT MODELS OF CARDIOVASCULAR DISEASE  

EPA Science Inventory

Increased oxidative stress and compromised antioxidant status are common pathologic factors of cardiovascular diseases (CVD). It is hypothesized that individuals with chronic CVD are more susceptible to environmental exposures due to underlying oxidative stress. To determine the ...

284

ALTERATIONS OF FE HOMEOSTASIS IN RAT CARDIOVASCULAR DISEASE MODELS AND ITS CONTRIBUTION TO CARDIOPULMONARY TOXICITY  

EPA Science Inventory

Introduction: Fe homeostasis can be disrupted in human cardiovascular diseases (CVD). We addressed how dysregulation of Fe homeostasis affected the pulmonary inflammation/oxidative stress response and disease progression after exposure to Libby amphibole (LA), an asbestifonn mine...

285

Image-Based Computational Fluid Dynamics in Blood Vessel Models: Toward Developing a Prognostic Tool to Assess Cardiovascular Function Changes in Prolonged Space Flights  

NASA Technical Reports Server (NTRS)

One of NASA's objectives is to be able to perform a complete, pre-flight, evaluation of cardiovascular changes in astronauts scheduled for prolonged space missions. Computational fluid dynamics (CFD) has shown promise as a method for estimating cardiovascular function during reduced gravity conditions. For this purpose, MRI can provide geometrical information, to reconstruct vessel geometries, and measure all spatial velocity components, providing location specific boundary conditions. The objective of this study was to investigate the reliability of MRI-based model reconstruction and measured boundary conditions for CFD simulations. An aortic arch model and a carotid bifurcation model were scanned in a 1.5T Siemens MRI scanner. Axial MRI acquisitions provided images for geometry reconstruction (slice thickness 3 and 5 mm; pixel size 1x1 and 0.5x0.5 square millimeters). Velocity acquisitions provided measured inlet boundary conditions and localized three-directional steady-flow velocity data (0.7-3.0 L/min). The vessel walls were isolated using NIH provided software (ImageJ) and lofted to form the geometric surface. Constructed and idealized geometries were imported into a commercial CFD code for meshing and simulation. Contour and vector plots of the velocity showed identical features between the MRI velocity data, the MRI-based CFD data, and the idealized-geometry CFD data, with less than 10% differences in the local velocity values. CFD results on models reconstructed from different MRI resolution settings showed insignificant differences (less than 5%). This study illustrated, quantitatively, that reliable CFD simulations can be performed with MRI reconstructed models and gives evidence that a future, subject-specific, computational evaluation of the cardiovascular system alteration during space travel is feasible.

Chatzimavroudis, George P.; Spirka, Thomas A.; Setser, Randolph M.; Myers, Jerry G.

2004-01-01

286

Cardiovascular group  

NASA Technical Reports Server (NTRS)

As a starting point, the group defined a primary goal of maintaining in flight a level of systemic oxygen transport capacity comparable to each individual's preflight upright baseline. The goal of maintaining capacity at preflight levels would seem to be a reasonable objective for several different reasons, including the maintenance of good health in general and the preservation of sufficient cardiovascular reserve capacity to meet operational demands. It is also important not to introduce confounding variables in whatever other physiological studies are being performed. A change in the level of fitness is likely to be a significant confounding variable in the study of many organ systems. The principal component of the in-flight cardiovascular exercise program should be large-muscle activity such as treadmill exercise. It is desirable that at least one session per week be monitored to assure maintenance of proper functional levels and to provide guidance for any adjustments of the exercise prescription. Appropriate measurements include evaluation of the heart-rate/workload or the heart-rate/oxygen-uptake relationship. Respiratory gas analysis is helpful by providing better opportunities to document relative workload levels from analysis of the interrelationships among VO2, VCO2, and ventilation. The committee felt that there is no clear evidence that any particular in-flight exercise regimen is protective against orthostatic hypotension during the early readaptation phase. Some group members suggested that maintenance of the lower body muscle mass and muscle tone may be helpful. There is also evidence that late in-flight interventions to reexpand blood volume to preflight levels are helpful in preventing or minimizing postflight orthostatic hypotension.

Blomqvist, Gunnar

1989-01-01

287

Evaluation of the Educational Value of YouTube Videos About Physical Examination of the Cardiovascular and Respiratory Systems  

PubMed Central

Background A number of studies have evaluated the educational contents of videos on YouTube. However, little analysis has been done on videos about physical examination. Objective This study aimed to analyze YouTube videos about physical examination of the cardiovascular and respiratory systems. It was hypothesized that the educational standards of videos on YouTube would vary significantly. Methods During the period from November 2, 2011 to December 2, 2011, YouTube was searched by three assessors for videos covering the clinical examination of the cardiovascular and respiratory systems. For each video, the following information was collected: title, authors, duration, number of viewers, and total number of days on YouTube. Using criteria comprising content, technical authority, and pedagogy parameters, videos were rated independently by three assessors and grouped into educationally useful and non-useful videos. Results A total of 1920 videos were screened. Only relevant videos covering the examination of adults in the English language were identified (n=56). Of these, 20 were found to be relevant to cardiovascular examinations and 36 to respiratory examinations. Further analysis revealed that 9 provided useful information on cardiovascular examinations and 7 on respiratory examinations: scoring mean 14.9 (SD 0.33) and mean 15.0 (SD 0.00), respectively. The other videos, 11 covering cardiovascular and 29 on respiratory examinations, were not useful educationally, scoring mean 11.1 (SD 1.08) and mean 11.2 (SD 1.29), respectively. The differences between these two categories were significant (P<.001 for both body systems). The concordance between the assessors on applying the criteria was 0.89, with a kappa score >.86. Conclusions A small number of videos about physical examination of the cardiovascular and respiratory systems were identified as educationally useful; these videos can be used by medical students for independent learning and by clinical teachers as learning resources. The scoring system utilized by this study is simple, easy to apply, and could be used by other researchers on similar topics. PMID:24225171

2013-01-01

288

Autonomic control of cardiovascular system in pre- and postmenopausal women: a cross-sectional study  

PubMed Central

Objective The aim of this cross-sectional study was to assess the features of autonomic control of the cardiovascular system in pre- and postmenopausal women. Material and Methods We studied 185 postmenopausal women aged 59.3±8.5 years (mean±SD) and 104 premenopausal women aged 45.1±5.8 years. Standard indices of heart rate variability (HRV) (mean heart rate, coefficient of variation, standard deviation of the NN interval (the time elapsing between two consecutive R waves in the electrocardiogram with normal sinus rhythm) (SDNN), square root of the mean squared differences of successive NN intervals (RMSSD), proportion derived by dividing RR50, the number of interval differences of successive NN intervals greater than 50 ms, by the total number of NN intervals (PNN50), and power of low frequency (LF) and high frequency (HF) bands in absolute values and percentages of total spectral power) and index S of synchronization between the 0.1-Hz rhythms in heart rate and photoplethysmogram were compared between these two groups at rest. We assessed the following sex hormones: estradiol, follicle stimulating hormone, dehydroepiandrosterone sulfate, and testosterone. Results Mean heart rate and power of LF and HF bands were significantly different (p<0.05) in pre- and postmenopausal women. The autonomic indices were similar in women with natural and surgical menopause. Some indices (coefficient of variation, SDNN, RMSSD, PNN50, and power of LF and HF bands) showed weak correlation with menopause time in women with natural menopause. In women with surgical menopause, a moderate statistically significant correlation was observed only between menopause time and S index (r=?0.41, p=0.039). In premenopausal women, only testosterone correlated weakly with coefficient of variation, SDNN, PNN50, RMSSD, and power of HF band. In postmenopausal women, no correlations were found. We did not find any significant relationship between autonomic indices and hot flashes, assessed by hot flash diary. Conclusion We did not find a clinically important relationship between cardiovascular autonomic control and menopausal status in women. PMID:25788843

Neufeld, Irina W.; Kiselev, Anton R.; Karavaev, Antoly S.; Prokhorov, Mikhail D.; Gridnev, Vladimir I.; Ponomarenko, Vladimir I.; Bezruchko, Boris P.

2015-01-01

289

Options for new real-time image-processing architectures in cardiovascular systems  

NASA Astrophysics Data System (ADS)

Low-dose X-ray imaging, diagnosis by image analysis and multi-modal medical imaging are example aspects that lead to more advanced image processing algorithms and the corresponding platforms on which they have to be executed. In this paper, we investigate the applicability of commercially available off-the-shelf components for a new computing platform. In the analysis, we will comply to some specific use cases. In cardiovascular minimal invasive surgery, physicians require low-latency imaging applications, as their actions must be directly visible on the screen. Typical image-processing algorithms in this domain are based on multi-resolution decomposition, noise reduction, image analysis and enhancement techniques. We have compared various solutions for possible processing architectures. The most interesting technology areas for constituting a new architecture are presented and we discuss the mapping of the use cases onto the various architectural proposals. Results show that a heterogeneous architecture gives the highest potential for current and upcoming image-processing applications. However, hardware and software solutions to support low-latency, high-bandwidth image streaming and an efficient concurrent distribution of functionality still need further development. This validates a clear direction for the future, which is based on modeling streaming computing architectures and special interconnect infrastructures.

Albers, Rob; Boosten, Marcel; de With, Peter H. N.

2007-03-01

290

Impact of Bisphenol A on the Cardiovascular System — Epidemiological and Experimental Evidence and Molecular Mechanisms  

PubMed Central

Bisphenol A (BPA) is a ubiquitous plasticizing agent used in the manufacturing of polycarbonate plastics and epoxy resins. There is well-documented and broad human exposure to BPA. The potential risk that BPA poses to the human health has attracted much attention from regulatory agencies and the general public, and has been extensively studied. An emerging and rapidly growing area in the study of BPA’s toxicity is its impact on the cardiovascular (CV) system. Recent epidemiological studies have shown that higher urinary BPA concentration in humans is associated with various types of CV diseases, including angina, hypertension, heart attack and coronary and peripheral arterial disease. Experimental studies have demonstrated that acute BPA exposure promotes the development of arrhythmias in female rodent hearts. Chronic exposure to BPA has been shown to result in cardiac remodeling, atherosclerosis, and altered blood pressure in rodents. The underlying mechanisms may involve alteration of cardiac Ca2+ handling, ion channel inhibition/activation, oxidative stress, and genome/transcriptome modifications. In this review, we discuss these recent findings that point to the potential CV toxicity of BPA, and highlight the knowledge gaps in this growing research area. PMID:25153468

Gao, Xiaoqian; Wang, Hong-Sheng

2014-01-01

291

Using an Informal Cardiovascular System Activity to Study the Effectiveness of Science Education in Unexpected Places  

NASA Astrophysics Data System (ADS)

Venues for informal science education are usually those sought out by people who are specifically looking for an educational experience. Whether planning a trip to a museum or choosing a television program, these individuals are actively seeking an informal educational experience; they are a self-selected group. This paper investigates whether members of the public will respond to an informal science activity that is placed in a location where learning about science would be unexpected. This project developed and used an activity about the cardiovascular system in which participants were able to walk the path of blood flow through the heart, body, and lungs. This activity was tested in two types of settings: where science was either expected or unexpected. A non-traditional assessment method was used to evaluate the effectiveness of the activity in the unexpected versus the expected settings. Ultimately, the activity was found to be equally effective in both settings, providing evidence for success in bringing informal science education to the general population in non-traditional venues.

Monzack, Elyssa Lynne; Petersen, Greta M. Zenner

2011-08-01

292

Impact of bisphenol a on the cardiovascular system - epidemiological and experimental evidence and molecular mechanisms.  

PubMed

Bisphenol A (BPA) is a ubiquitous plasticizing agent used in the manufacturing of polycarbonate plastics and epoxy resins. There is well-documented and broad human exposure to BPA. The potential risk that BPA poses to the human health has attracted much attention from regulatory agencies and the general public, and has been extensively studied. An emerging and rapidly growing area in the study of BPA's toxicity is its impact on the cardiovascular (CV) system. Recent epidemiological studies have shown that higher urinary BPA concentration in humans is associated with various types of CV diseases, including angina, hypertension, heart attack and coronary and peripheral arterial disease. Experimental studies have demonstrated that acute BPA exposure promotes the development of arrhythmias in female rodent hearts. Chronic exposure to BPA has been shown to result in cardiac remodeling, atherosclerosis, and altered blood pressure in rodents. The underlying mechanisms may involve alteration of cardiac Ca2+ handling, ion channel inhibition/activation, oxidative stress, and genome/transcriptome modifications. In this review, we discuss these recent findings that point to the potential CV toxicity of BPA, and highlight the knowledge gaps in this growing research area. PMID:25153468

Gao, Xiaoqian; Wang, Hong-Sheng

2014-08-01

293

Increased proteoglycan synthesis by the cardiovascular system of coarctation hypertensive rats  

SciTech Connect

Proteoglycan (PG) synthesis in the cardiovascular system of coarctation hypertensive rats was examined by in vivo and in vitro labeling of glycosaminoglycans with 35SO4 in rats made hypertensive for short (4 days) and longer (14 days) durations. With in vivo labeling, only tissues directly exposed to elevated pressure (left ventricle, LV and aorta above the clip, AOR increases) exhibited elevated PG synthesis after 4 days of hypertension. By 14 days, tissues both exposed to (LV and AOR increases) and protected from elevated pressure (right ventricle and kidney) exhibited elevated PG synthetic rates. Slight elevations in the proportion of galactosaminoglycans were observed with a concurrent proportional decrease in heparan sulfate PGs. Using the in vitro labeling procedure, no significant increases in PG synthesis were observed in any tissue at either 4 days or 14 days of hypertension. These data indicate that: (1) coarctation hypertension stimulates PG production that is dependent initially on increased pressure and later, on additional non-pressure related factors, (2) these other factors are responsible for enhanced PG production in tissues not directly exposed to pressure overload, (3) pressure and/or these other factors are essential for enhanced PG production in coarctation hypertension, and (4) synthesis of all GAG types appears to be affected.

Lipke, D.W.; Couchman, J.R. (Hypertension Program, University of Alabama, Birmingham (USA))

1991-06-01

294

Development of Anatomophysiologic Knowledge Regarding the Cardiovascular System: From Egyptians to Harvey  

PubMed Central

Our knowledge regarding the anatomophysiology of the cardiovascular system (CVS) has progressed since the fourth millennium BC. In Egypt (3500 BC), it was believed that a set of channels are interconnected to the heart, transporting air, urine, air, blood, and the soul. One thousand years later, the heart was established as the center of the CVS by the Hippocratic Corpus in the medical school of Kos, and some of the CVS anatomical characteristics were defined. The CVS was known to transport blood via the right ventricle through veins and the pneuma via the left ventricle through arteries. Two hundred years later, in Alexandria, following the development of human anatomical dissection, Herophilus discovered that arteries were 6 times thicker than veins, and Erasistratus described the semilunar valves, emphasizing that arteries were filled with blood when ventricles were empty. Further, 200 years later, Galen demonstrated that arteries contained blood and not air. With the decline of the Roman Empire, Greco-Roman medical knowledge about the CVS was preserved in Persia, and later in Islam where, Ibn Nafis inaccurately described pulmonary circulation. The resurgence of dissection of the human body in Europe in the 14th century was associated with the revival of the knowledge pertaining to the CVS. The main findings were the description of pulmonary circulation by Servetus, the anatomical discoveries of Vesalius, the demonstration of pulmonary circulation by Colombo, and the discovery of valves in veins by Fabricius. Following these developments, Harvey described blood circulation. PMID:25590934

Bestetti, Reinaldo Bulgarelli; Restini, Carolina Baraldi A.; Couto, Lucélio B.

2014-01-01

295

Spectrofluorimetric methods of stability-indicating assay of certain drugs affecting the cardiovascular system  

NASA Astrophysics Data System (ADS)

Two stability-indicating spectrofluorimetric methods have been developed for the determination of ezetimibe and olmesartan medoxomil, drugs affecting the cardiovascular system, and validated in the presence of their degradation products. The first method, for ezetimibe, is based on an oxidative coupling reaction of ezetimibe with 3-methylbenzothiazolin-2-one hydrazone hydrochloride in the presence of cerium (IV) ammonium sulfate in an acidic medium. The quenching effect of ezetimibe on the fluorescence of excess cerous ions is measured at the emission wavelength, ?em, of 345 nm with the excitation wavelength, ?ex, of 296 nm. Factors affecting the reaction were carefully studied and optimized. The second method, for olmesartan medoxomil, is based on measuring the native fluorescence intensity of olmesartan medoxomil in methanol at ?em = 360 nm with ?ex = 286 nm. Regression plots revealed good linear relationships in the assay limits of 10-120 and 8-112 g/ml for ezetimibe and olmesartan medoxomil, respectively. The validity of the methods was assessed according to the United States Pharmacopeya guidelines. Statistical analysis of the results exposed good Student's t-test and F-ratio values. The introduced methods were successfully applied to the analysis of ezetimibe and olmesartan medoxomil in drug substances and drug products as well as in the presence of their degradation products.

Moussa, B. A.; Mohamed, M. F.; Youssef, N. F.

2011-01-01

296

Incidence of and Risk Factors for Adverse Cardiovascular Events Among Patients With Systemic Lupus Erythematosus  

PubMed Central

Patients with systemic lupus erythematosus (SLE) are at excess risk of cardiovascular events (CVEs). There is uncertainty regarding the relative importance of SLE disease activity, medications, or traditional risk factors in this increased risk. To gain insight into this, the authors analyzed data from a cohort of 1,874 patients with SLE who were seen quarterly at a single clinical center (April 1987–June 2010) using pooled logistic regression analysis. In 9,485 person-years of follow-up, the authors observed 134 CVEs (rate = 14.1/1,000 person-years). This was 2.66 times what would be expected in the general population based on Framingham risk scores (95% confidence interval: 2.16, 3.16). After adjustment for age, CVE rates were not associated with duration of SLE. However, they were associated with average past levels of SLE disease activity and recent levels of circulating anti-double-stranded DNA. Past use of corticosteroids (in the absence of current use) was not associated with CVE rates. However, persons currently using 20 mg/day or more of corticosteroids had a substantial increase in risk even after adjustment for disease activity. Thus, consistent with findings in several recent publications among cohorts with other diseases, current use of corticosteroids was associated with an increased risk of CVEs. These results suggest a short-term impact of corticosteroids on CVE risk. PMID:23024137

Magder, Laurence S.; Petri, Michelle

2012-01-01

297

Does early intensive multifactorial therapy reduce modelled cardiovascular risk in individuals with screen-detected diabetes? Results from the ADDITION-Europe cluster randomized trial  

PubMed Central

Aims Little is known about the long-term effects of intensive multifactorial treatment early in the diabetes disease trajectory. In the absence of long-term data on hard outcomes, we described change in 10-year modelled cardiovascular risk in the 5 years following diagnosis, and quantified the impact of intensive treatment on 10-year modelled cardiovascular risk at 5 years. Methods In a pragmatic, cluster-randomized, parallel-group trial in Denmark, the Netherlands and the UK, 3057 people with screen-detected Type 2 diabetes were randomized by general practice to receive (1) routine care of diabetes according to national guidelines (1379 patients) or (2) intensive multifactorial target-driven management (1678 patients). Ten-year modelled cardiovascular disease risk was calculated at baseline and 5 years using the UK Prospective Diabetes Study Risk Engine (version 3?). Results Among 2101 individuals with complete data at follow up (73.4%), 10-year modelled cardiovascular disease risk was 27.3% (sd 13.9) at baseline and 21.3% (sd 13.8) at 5-year follow-up (intensive treatment group difference –6.9, sd 9.0; routine care group difference –5.0, sd 12.2). Modelled 10-year cardiovascular disease risk was lower in the intensive treatment group compared with the routine care group at 5 years, after adjustment for baseline cardiovascular disease risk and clustering (–2.0; 95% CI –3.1 to –0.9). Conclusions Despite increasing age and diabetes duration, there was a decline in modelled cardiovascular disease risk in the 5 years following diagnosis. Compared with routine care, 10-year modelled cardiovascular disease risk was lower in the intensive treatment group at 5 years. Our results suggest that patients benefit from intensive treatment early in the diabetes disease trajectory, where the rate of cardiovascular disease risk progression may be slowed. PMID:24533664

Black, J A; Sharp, S J; Wareham, N J; Sandbæk, A; Rutten, G E H M; Lauritzen, T; Khunti, K; Davies, M J; Borch-Johnsen, K; Griffin, S J; Simmons, R K

2014-01-01

298

Physics-driven CFD modeling of complex anatomical cardiovascular flows-a TCPC case study.  

PubMed

Recent developments in medical image acquisition combined with the latest advancements in numerical methods for solving the Navier-Stokes equations have created unprecedented opportunities for developing simple and reliable computational fluid dynamics (CFD) tools for meeting patient-specific surgical planning objectives. However, for CFD to reach its full potential and gain the trust and confidence of medical practitioners, physics-driven numerical modeling is required. This study reports on the experience gained from an ongoing integrated CFD modeling effort aimed at developing an advanced numerical simulation tool capable of accurately predicting flow characteristics in an anatomically correct total cavopulmonary connection (TCPC). An anatomical intra-atrial TCPC model is reconstructed from a stack of magnetic resonance (MR) images acquired in vivo. An exact replica of the computational geometry was built using transparent rapid prototyping. Following the same approach as in earlier studies on idealized models, flow structures, pressure drops, and energy losses were assessed both numerically and experimentally, then compared. Numerical studies were performed with both a first-order accurate commercial software and a recently developed, second-order accurate, in-house flow solver. The commercial CFD model could, with reasonable accuracy, capture global flow quantities of interest such as control volume power losses and pressure drops and time-averaged flow patterns. However, for steady inflow conditions, both flow visualization experiments and particle image velocimetry (PIV) measurements revealed unsteady, complex, and highly 3D flow structures, which could not be captured by this numerical model with the available computational resources and additional modeling efforts that are described. Preliminary time-accurate computations with the in-house flow solver were shown to capture for the first time these complex flow features and yielded solutions in good agreement with the experimental observations. Flow fields obtained were similar for the studied total cardiac output range (1-3 1/min); however hydrodynamic power loss increased dramatically with increasing cardiac output, suggesting significant energy demand at exercise conditions. The simulation of cardiovascular flows poses a formidable challenge to even the most advanced CFD tools currently available. A successful prediction requires a two-pronged, physics-based approach, which integrates high-resolution CFD tools and high-resolution laboratory measurements. PMID:15868719

Pekkan, Kerem; de Zélicourt, Diane; Ge, Liang; Sotiropoulos, Fotis; Frakes, David; Fogel, Mark A; Yoganathan, Ajit P

2005-03-01

299

Arsenic-Induced Oxidative Stress: Evidence on In Vitro Models of Cardiovascular, Diabetes Mellitus Type 2 and Neurodegenerative Disorders  

Microsoft Academic Search

\\u000a This chapter provides an overview of the evidence of oxidative stress and compensatory responses in response to arsenic exposure\\u000a in diverse in vitro models of cardiovascular diseases, type 2 diabetes mellitus and neurodegenerative disorders. The studies\\u000a described here are recent approaches related to (1) the presence of oxidative and nitrosative damage; (2) the activation of\\u000a novel and sensitive oxidative stress

Rubén Ruíz-Ramos; Patricia Ostrosky-Wegman; Mariano E. Cebrián

300

Modelling the lymphatic system: challenges and opportunities  

PubMed Central

The lymphatic system is a vital part of the circulatory and immune systems, and plays an important role in homeostasis by controlling extracellular fluid volume and in combating infection. Nevertheless, there is a notable disparity in terms of research effort expended in relation to the treatment of lymphatic diseases in contrast to the cardiovascular system. While similarities to the cardiovascular system exist, there are considerable differences in their anatomy and physiology. This review outlines some of the challenges and opportunities for those engaged in modelling biological systems. The study of the lymphatic system is still in its infancy, the vast majority of the models presented in the literature to date having been developed since 2003. The number of distinct models and their variants are few in number, and only one effort has been made thus far to study the entire lymphatic network; elements of the lymphatic system such as the nodes, which act as pumps and reservoirs, have not been addressed by mathematical models. Clearly, more work will be necessary in combination with experimental verification in order to progress and update the knowledge on the function of the lymphatic system. As our knowledge and understanding of its function increase, new and more effective treatments of lymphatic diseases are bound to emerge. PMID:22237677

Margaris, K. N.; Black, R. A.

2012-01-01

301

The prognostic significance of the adaptation potential of the cardiovascular system in 10- and 11-year-old children  

Microsoft Academic Search

Experimental physiological studies were made in 10–11-year-old boys and girls, students of a gymnasium and an education-upbringing\\u000a complex. The functional parameters recorded in children momentarily included: the heart rate, systolic and diastolic arterial\\u000a pressure, Roufier index, and the adaptation potential (AP) of the cardiovascular system as an integral index of the adaptivity\\u000a level of human organism on the whole, measured

M. V. Antropova; G. V. Borodkina; L. M. Kuznetsova; G. G. Manke; T. M. Paranicheva

2000-01-01

302

MRI-Based Computational Fluid Dynamics in Experimental Vascular Models: Toward the Development of an Approach for Prediction of Cardiovascular Changes During Prolonged Space Missions  

NASA Technical Reports Server (NTRS)

A priority of NASA is to identify and study possible risks to astronauts health during prolonged space missions [l]. The goal is to develop a procedure for a preflight evaluation of the cardiovascular system of an astronaut and to forecast how it will be affected during the mission. To predict these changes, a computational cardiovascular model must be constructed. Although physiology data can be used to make a general model, a more desirable subject-specific model requires anatomical, functional, and flow data from the specific astronaut. MRI has the unique advantage of providing images with all of the above information, including three-directional velocity data which can be used as boundary conditions in a computational fluid dynamics (CFD) program [2,3]. MRI-based CFD is very promising for reproduction of the flow patterns of a specific subject and prediction of changes in the absence of gravity. The aim of this study was to test the feasibility of this approach by reconstructing the geometry of MRI-scanned arterial models and reproducing the MRI-measured velocities using CFD simulations on these geometries.

Spirka, T. A.; Myers, J. G.; Setser, R. M.; Halliburton, S. S.; White, R. D.; Chatzimavroudis, G. P.

2005-01-01

303

Alterations in the coagulation system of active smokers from the Ludwigshafen Risk and Cardiovascular Health (LURIC) study.  

PubMed

Smoking is an important and preventable risk factor of cardiovascular diseases with effects on blood coagulation. Our aim was to analyze the influence of smoking on coagulation parameters. Concentrations or activities of blood coagulation factors were compared in 777 active smokers and 1,178 lifetime non-smokers of the Ludwigshafen Risk and Cardiovascular Health (LURIC) study. The association with mortality was examined using Cox regression. The findings show that AS had a tendency toward thrombosis. They displayed significantly higher values for fibrinogen, soluble fibrinogen, factor XIII, and tissue factor pathway inhibitor; whereas FVII, FVIII, FXII, von Willebrand factor (vWF), and thrombomodulin were decreased. The Cox regression analysis showed fibrinogen, FVIII, vWF, thrombomodulin, and tissue factor pathway inhibitor to be independent risk factors for mortality in active smokers with hazard ratios of 1.16 (95% CI: 1.02-1.31), 1.40 (1.22-1.59), 1.37 (1.22-1.56), 1.19 (1.07-1.31), and 1.22 (1.06-1.40) per increase of one standard deviation. We conclude that active smokers have an increased thrombogenic potential associated with significant changes in the coagulation system. Individual parameters of the coagulation system are independent predictors of mortality. Therefore, parameters of the coagulation system, apart from other risk factors for cardiovascular disease (e.g., lipids or life-style) should be determined for risk prediction in active smokers. PMID:25300683

Delgado, G; Siekmeier, R; Grammer, T B; Boehm, B O; März, W; Kleber, M E

2015-01-01

304

Developmental plasticity in the cardiovascular system of fish, with special reference to the zebrafish.  

PubMed

During development the circulatory system of vertebrates typically starts operating earlier than any other organ. In these early stages, however, blood flow is not yet linked to metabolic requirements of tissues, as is well established for adults. While the autonomic nervous system becomes functional only quite late during development, in the early stages control of blood flow appears to be possible by blood-borne and/or local hormones. This study presents methods based on video-imaging techniques and fluorescence microscopy to visualize cardiac activity, as well as the vascular bed of developing lower vertebrates, and tests the idea that environmental factors, such as hypoxia, may modify cardiac activity, or even the early formation of blood vessels in embryos and larvae. In zebrafish larvae, adaptations of cardiovascular activity to chronic hypoxia become visible shortly after hatching, and the formation of some blood vessels is enhanced under chronic hypoxia. Exposure of early larval stages of zebrafish to a constant water current induces physiological adaptations, resulting in enhanced swimming efficiency and increased tolerance towards hypoxia. Furthermore, application of hormones such as NO can modify cardiac activity as well as peripheral resistance, and they can stimulate blood vessel formation. In consequence, even during early development of fish or amphibian larvae, the performance of cardiac muscle and of skeletal muscle can be modified by environmental influences and peripheral resistance can be adjusted. Even blood vessel formation can be stimulated by hypoxia, for example, or by the presence of specific hormones. Thus, at approximately the time of hatching the physiological performance of vertebrate larvae is already determined by the combined action of environmental influences and of genetic information. PMID:12443913

Pelster, Bernd

2002-11-01

305

A biochemical rationale for the discrete behavior of nitroxyl and nitric oxide in the cardiovascular system.  

PubMed

The redox siblings nitroxyl (HNO) and nitric oxide (NO) have often been assumed to undergo casual redox reactions in biological systems. However, several recent studies have demonstrated distinct pharmacological effects for donors of these two species. Here, infusion of the HNO donor Angeli's salt into normal dogs resulted in elevated plasma levels of calcitonin gene-related peptide, whereas neither the NO donor diethylamine/NONOate nor the nitrovasodilator nitroglycerin had an appreciable effect on basal levels. Conversely, plasma cGMP was increased by infusion of diethylamine/NONOate or nitroglycerin but was unaffected by Angeli's salt. These results suggest the existence of two mutually exclusive response pathways that involve stimulated release of discrete signaling agents from HNO and NO. In light of both the observed dichotomy of HNO and NO and the recent determination that, in contrast to the O2/O2- couple, HNO is a weak reductant, the relative reactivity of HNO with common biomolecules was determined. This analysis suggests that under biological conditions, the lifetime of HNO with respect to oxidation to NO, dimerization, or reaction with O2 is much longer than previously assumed. Rather, HNO is predicted to principally undergo addition reactions with thiols and ferric proteins. Calcitonin gene-related peptide release is suggested to occur via altered calcium channel function through binding of HNO to a ferric or thiol site. The orthogonality of HNO and NO may be due to differential reactivity toward metals and thiols and in the cardiovascular system, may ultimately be driven by respective alteration of cAMP and cGMP levels. PMID:12865500

Miranda, Katrina M; Paolocci, Nazareno; Katori, Tatsuo; Thomas, Douglas D; Ford, Eleonora; Bartberger, Michael D; Espey, Michael G; Kass, David A; Feelisch, Martin; Fukuto, Jon M; Wink, David A

2003-08-01

306

Psoriasis and cardiovascular disorders.  

PubMed

There is considerable evidence to show that patients with moderate-to-severe psoriasis have a significantly increased risk of cardiovascular disease and cardiovascular risk factors such as obesity, diabetes mellitus, the metabolic syndrome and smoking compared to the general population. The mechanistic link between psoriasis and this observed increase in cardiovascular co-morbidities has not been fully defined. It is clear, however, that common inflammatory pathways are at play in the pathophysiology of psoriasis, obesity and coronary artery disease. It had been proposed that the control of systemic inflammation in psoriasis could help reduce cardiovascular morbidity, and retrospective studies of methotrexate and anti-TNF-a agents have suggested a cardio-protective effect with use of these agents. More recently, however, there have been concerns regarding a potential excess of cardiovascular events with the newer generation of anti-interleukin-12p40 antibodies. In this article we review the association of psoriasis with cardiovascular disorders and the effects of current psoriasis therapies on cardiovascular risk. PMID:22481581

Ryan, C; Menter, A

2012-04-01

307

Increased susceptibility to cardiovascular effects of dihydrocapcaicin in resuscitated rats. Cardiovascular effects of dihydrocapsaicin  

Microsoft Academic Search

BACKGROUND: Survivors of a cardiac arrest often have persistent cardiovascular derangements following cardiopulmonary resuscitation including decreased cardiac output, arrhythmias and morphological myocardial damage. These cardiovascular derangements may lead to an increased susceptibility towards the external and internal environment of the cardiovascular system as compared to the healthy situation. METHODS: Here we tested the hypothesis that the cardiovascular system in healthy

Keld Fosgerau; Giuseppe Ristagno; Magdalena Jayatissa; Mads Axelsen; Jacob W Gotfredsen; Uno J Weber; Lars Køber; Christian Torp-Pedersen; Charlotte Videbaek

2010-01-01

308

The effects of obstructive sleep apnea syndrome due to adenotonsillar hypertrophy on the cardiovascular system in children.  

PubMed

Obstructive sleep apnea syndrome (OSAS) due to adenotonsillar hypertrophy (ATH) is a common and important problem in children. OSAS can lead to significant cardiopulmonary complications, poor growth and problems with learning and behavior. Many studies in the literature show that OSAS due to ATH causes pulmonary hypertension, ventricular hypertrophy and systemic hypertension in the pediatric population. In this review, we discuss the effects of ATH on cardiac function. It is well known that as a child grows, the nasopharyngeal passage becomes enlarged, helping to improve OSAS. Based on this, we discuss the possible positive effect of this age-related improvement on the obstruction of cardiovascular disturbances. Finally, the possible relationship between the duration of OSAS and the timing of surgery with the permanency of cardiovascular disturbances is discussed. PMID:21980836

Tatlipinar, Arzu; Duman, Dursun; Uslu, Celil; Egeli, Erol

2011-01-01

309

Genome-wide identification of long noncoding RNAs in rat models of cardiovascular and renal disease.  

PubMed

Long noncoding RNAs (lncRNAs) are an emerging class of genomic regulatory molecules reported in various species. In the rat, which is one of the major mammalian model organisms, discovery of lncRNAs on a genome-wide scale is lagging. Renal lncRNA sequencing and lncRNA transcriptome analysis were conducted in 3 rat strains that are widely used in cardiovascular and renal research: the Dahl salt-sensitive rat, the spontaneously hypertensive rat, and the Dahl salt-resistant rat. Through the RNA sequencing approach, 3273 transcripts were identified as rat lncRNAs. A majority of lncRNAs were without predicted target genes. Differential expression of 273 and 749 lncRNAs was detected between Dahl salt-sensitive versus Dahl salt-resistant and Dahl salt-sensitive versus spontaneously hypertensive rat comparisons, respectively. To couple the observed differential expression of lncRNAs with the status of mRNAs, an mRNA transcriptome analysis was conducted. Several cis mRNA genes were coregulated with lncRNAs. Of these, the protein expression status of 4 target genes, Asb3, Chac2, Pex11b, and Sp5, were differentially expressed between the relevant strain comparisons, thereby suggesting that the differentially expressed lncRNAs associated with these genes are candidate genetic determinants of blood pressure. This study serves as a first-generation catalog of rat lncRNAs and illustrates the prioritization of lncRNAs as candidates for complex polygenic traits. PMID:25385761

Gopalakrishnan, Kathirvel; Kumarasamy, Sivarajan; Mell, Blair; Joe, Bina

2015-01-01

310

Multifractality in the Peripheral Cardiovascular System from Pointwise Holder Exponents of Laser Doppler Flowmetry Signals  

E-print Network

'Angers, Angers, France ABSTRACT We study the dynamics of skin laser Doppler flowmetry signals giving a peripheral cardiovascular signals? Herein we report that skin laser Doppler flowmetry signals display multifractal Doppler Flowmetry Signals Anne Humeau,*y Francxois Chapeau-Blondeau,y David Rousseau,y Maylis Tartas,z Be

Chapeau-Blondeau, François

311

Flipped Classroom Model Improves Graduate Student Performance in Cardiovascular, Respiratory, and Renal Physiology  

ERIC Educational Resources Information Center

The purpose of this study was to assess the effectiveness of a traditional lecture-based curriculum versus a modified "flipped classroom" curriculum of cardiovascular, respiratory, and renal physiology delivered to first-year graduate students. Students in both courses were provided the same notes and recorded lectures. Students in the…

Tune, Johnathan D.; Sturek, Michael; Basile, David P.

2013-01-01

312

CARDIOVASCULAR DISEASES, SUSCEPTIBILITY TO OXIDATIVE INJURY AND COMPENSATORY MECHANISMS: INSIGHTS FROM RODENT MODELS  

EPA Science Inventory

Cardiovascular diseases (CVD) are the number one cause for human mortality and nearly 25% of the population develops chronic CVD at an age of 65 years or older. Environmental and genetic interactions govern pathogenesis. Increased oxidative stress and compromised antioxidant stat...

313

Hormone Replacement Therapy and Cardiovascular Disease: Lessons from a Monkey Model of Postmenopausal Women  

Microsoft Academic Search

Concerns exist about the cardiovascular effects of hormone replacement therapy (HRT) in postmenopausal women be- cause results from the Women's Health Initiative (WHI) and the Heart and Estrogen\\/Progestin Replacement Study (HERS) are contradictory. In both of these studies, post- menopausal conjugated equine estrogens + medroxyproges- terone acetate did not reduce risk, and somewhat increased the risk of myocardial infarction in

J. Koudy Williams; Irma Suparto

2004-01-01

314

Examination of Susceptibility to Libby Amphibole Asbestos-Induced Injury in Rat Models of Cardiovascular Disease  

EPA Science Inventory

Although cardiovascular disease (CVD) is considered a risk factor for the exacerbation of air pollution health effects, no studies have been done assessing the influence of the disease on the development of lung injury induced by asbestos exposure. In this study we examined lung ...

315

A novel class of advanced glycation inhibitors ameliorates renal and cardiovascular damage in experimental rat models  

Microsoft Academic Search

Background. The reno- and cardiovascular-protective effects of angiotensin II receptor blockers (ARBs), have been ascribed, at least in part, to their ability to inhibit the formation of advanced glycation end products (AGEs), independently of their effect on blood pressure. They act through decreased oxidative stress, unlike previously reported AGE inhibitors which entrap reactive carbonyl (RCOs) precursors of AGEs. The hypotensive

Yuko Izuhara; Masaomi Nangaku; Shunya Takizawa; Satoru Takahashi; Jing Shao; Hisashi Oishi; Hiroyuki Kobayashi; Toshio Miyata

2008-01-01

316

Sheep (Ovis aries) as a Model for Cardiovascular Surgery and Management before, during, and after Cardiopulmonary Bypass  

PubMed Central

Because of its similarity to humans in important respects, sheep (Ovis aries) are a common animal model for translational research in cardiovascular surgery. However, some unique aspects of sheep anatomy and physiology present challenges to its use in these complicated experiments. In this review, we discuss relevant anatomy and physiology of sheep and discuss management before, during, and after procedures requiring cardiopulmonary bypass to provide a concise source of information for veterinarians, technicians, and researchers developing and implementing protocols with this model. PMID:25255065

DiVincenti, Louis; Westcott, Robin; Lee, Candice

2014-01-01

317

TRC210258, a novel TGR5 agonist, reduces glycemic and dyslipidemic cardiovascular risk in animal models of diabesity  

PubMed Central

Background Patients with diabesity have a significantly increased risk of developing cardiovascular disease. Therefore, therapy addressing the multiple metabolic abnormalities linked with diabesity and leading to further reduction of cardiovascular risk is highly desirable. Activation of the TGR5 receptor holds therapeutic potential for diabesity. In the present study, we evaluated the efficacy of TRC210258, a novel TGR5 agonist, in clinically relevant animal models of diabesity. Methods A novel small molecule, TRC210258 (N-(4-chlorophenyl)-2-(4-fluorophenoxy)-N-methylimidazo (1, 2-a) pyrimidine-3-carboxamide), was synthesized. The in vitro TGR5 receptor activation potential of TRC210258 was assessed by cyclic adenosine monophosphate (cAMP) assay and cAMP-responsive element reporter assay using cells overexpressing the human TGR5 receptor. The effect of TRC210258 on glucagon-like peptide-1 release was evaluated in vitro using a human enteroendocrine cell line. The effect of TRC210258 on energy expenditure and glycemic control was evaluated in high-fat diet-induced obese mice. Additionally, the effect of TRC210258 on dyslipidemic parameters was determined in high fat-fed hamsters. Results TRC210258 demonstrated potent TGR5 agonist activity, with enhanced glucagon-like peptide-1 release and energy expenditure. Treatment with TRC210258 resulted in better glycemic control and improved parameters of dyslipidemia such as plasma triglyceride, low-density lipoprotein cholesterol, and non-high-density lipoprotein cholesterol levels. Treatment with TRC210258 also improved emerging dyslipidemic cardiovascular risk parameters, including remnant cholesterol and triglyceride clearance. Conclusion This study highlights the potential of TRC210258, a novel TGR5 agonist, to improve dyslipidemic cardiovascular risk beyond glycemic control in patients with type 2 diabetes. PMID:24379686

Zambad, Shitalkumar P; Tuli, Davinder; Mathur, Anoop; Ghalsasi, Sameer A; Chaudhary, Anita R; Deshpande, Shailesh; Gupta, Ramesh C; Chauthaiwale, Vijay; Dutt, Chaitanya

2014-01-01

318

Long?Term Renal Denervation Normalizes Disrupted Blood Pressure Circadian Rhythm and Ameliorates Cardiovascular Injury in a Rat Model of Metabolic Syndrome  

PubMed Central

Background Although renal denervation significantly reduces blood pressure in patients with resistant hypertension, the role of the renal nerve in hypertension with metabolic syndrome is unknown. We investigated the impact of long?term renal denervation on SHR/NDmcr?cp(+/+) (SHRcp) rats, a useful rat model of metabolic syndrome, to determine the role of the renal nerve in hypertension with metabolic syndrome. Methods and Results SHRcp rats were divided into (1) a renal denervation (RD) group and (2) a sham operation group (control) to examine the effects of long?term RD on blood pressure circadian rhythm, renal sodium retention?related molecules, the renin?angiotensin?aldosterone system, metabolic disorders, and organ injury. RD in SHRcp rats not only significantly reduced blood pressure but also normalized blood pressure circadian rhythm from the nondipper to the dipper type, and this improvement was associated with an increase in urinary sodium excretion and the suppression of renal Na+?Cl? cotransporter upregulation. RD significantly reduced plasma renin activity. RD significantly prevented cardiovascular remodeling and impairment of vascular endothelial function and attenuated cardiovascular oxidative stress. However, RD failed to ameliorate obesity, metabolic disorders, and renal injury and failed to reduce systemic sympathetic activity in SHRcp rats. Conclusions By including the upregulation of the Na+?Cl? cotransporter, the renal sympathetic nerve is involved in the disruption of blood pressure circadian rhythm as well as hypertension in metabolic syndrome. Thus, RD seems to be a useful therapeutic strategy for hypertension with metabolic syndrome. PMID:23974905

Katayama, Tetsuji; Sueta, Daisuke; Kataoka, Keiichiro; Hasegawa, Yu; Koibuchi, Nobutaka; Toyama, Kensuke; Uekawa, Ken; MingJie, Ma; Nakagawa, Takashi; Maeda, Masanobu; Ogawa, Hisao; Kim?Mitsuyama, Shokei

2013-01-01

319

A Molecular Communication System Model for Particulate Drug Delivery Systems.  

PubMed

The goal of a Drug Delivery System (DDS) is to convey a drug where the medication is needed, while, at the same time, preventing the drug from affecting other healthy parts of the body. Drugs composed of micro or nano-sized particles (particulate DDS) that are able to cross barriers which prevent large particles from escaping the bloodstream are used in the most advanced solutions.Molecular Communication (MC) is used as an abstraction of the propagation of drug particles in the body. MC is a new paradigm in communication research where the exchange of information is achieved through the propagation of molecules. Here, the transmitter is the drug injection, the receiver is the drug delivery and the channel is realized by the transport of drug particles, thus enabling the analysis and design of a particulate DDS using communication tools. This is achieved by modeling the MC channel as two separate contributions, namely, the cardiovascular network model and the drug propagation network. The cardiovascular network model allows to analytically compute the blood velocity profile in every location of the cardiovascular system given the flow input by the heart. The drug propagation network model allows the analytical expression of the drug delivery rate at the targeted site given the drug injection rate. Numerical results are also presented to assess the flexibility and accuracy of the developed model. The study of novel optimization techniques for a more effective and less invasive drug delivery will be aided by this model, while paving the way for novel communication techniques for Intra-Body communication Networks (IBN). PMID:23807425

Chahibi, Youssef; Pierobon, Massimiliano; Song, Sang Ok; Akyildiz, Ian

2013-06-27

320

Cardiovascular effects of resveratrol and atorvastatin treatments in an H2O2-induced stress model  

PubMed Central

Oxidative stress has been implicated in the pathophysiology of several types of cardiovascular disease (CVD). Statins are widely used to inhibit the progression of atherosclerosis and reduce the incidence of CVD. Certain over-the-counter products, including resveratrol, show similar effects to statins and may thus be used in conjunction with statins for the treatment of the majority of patients with CVD. The aim of the present study was to evaluate the effects of atorvastatin, resveratrol and resveratrol + atorvastatin (R+A) pretreatment on myocardial contractions and vascular endothelial functions in the presence of H2O2 as an experimental model of oxidative stress in rats. Four groups were established and referred to as the control, atorvastatin, resveratrol and R+A groups. Atorvastatin (40 mg/kg, per oral) and/or resveratrol (30 mg/kg, intraperitoneal) treatments were administered for 14 days. On the 15th day, the thoracic aortas and hearts of the rats were dissected and placed into isolated organ baths. Vascular responses to cumulative doses of H2O2 (1×10?8–1×10?4 M H2O2) with and without N (G)-nitro-L-arginine methyl ester (L-NAME) incubation were measured. In addition, myocardial electrical stimulation (ES) responses to various H2O2 concentrations (1×10?7–1×10?5 M H2O2) were evaluated. In the control and atorvastatin groups, H2O2 application caused a significant dose-dependent decrease in the ES-induced contractions in the myocardial tissue of rats. In the resveratrol and R+A groups, H2O2 application did not significantly affect myocardial contraction at any dose. In all groups, incubation with L-NAME caused a significant augmentation in the H2O2 response, revealing that this effect was mediated via the vascular endothelium. In conclusion, pretreatment with R+A for CVD appears to be superior to pretreatment with either agent alone. PMID:25289077

SONER, BURAK CEM; ?AHIN, AY?E SAIDE

2014-01-01

321

Applications of SPICE for modeling miniaturized biomedical sensor systems  

NASA Technical Reports Server (NTRS)

This paper proposes a model for a miniaturized signal conditioning system for biopotential and ion-selective electrode arrays. The system consists of three main components: sensors, interconnections, and signal conditioning chip. The model for this system is based on SPICE. Transmission-line based equivalent circuits are used to represent the sensors, lumped resistance-capacitance circuits describe the interconnections, and a model for the signal conditioning chip is extracted from its layout. A system for measurements of biopotentials and ionic activities can be miniaturized and optimized for cardiovascular applications based on the development of an integrated SPICE system model of its electrochemical, interconnection, and electronic components.

Mundt, C. W.; Nagle, H. T.

2000-01-01

322

GPER: a novel target for non-genomic estrogen action in the cardiovascular system.  

PubMed

A key to harnessing the enormous therapeutic potential of estrogens is understanding the diversity of estrogen receptors and their signaling mechanisms. In addition to the classic nuclear estrogen receptors (i.e., ER? and ER?), over the past decade a novel G-protein-coupled estrogen receptor (GPER) has been discovered in cancer and other cell types. More recently, this non-genomic signaling mechanism has been found in blood vessels, and mediates vasodilatory responses to estrogen and estrogen-like agents; however, downstream signaling events involved acute estrogen action remain unclear. The purpose of this review is to discuss the latest knowledge concerning GPER modulation of cardiovascular function, with a particular emphasis upon how activation of this receptor could mediate acute estrogen effects in the heart and blood vessels (i.e., vascular tone, cell growth and differentiation, apoptosis, endothelial function, myocardial protection). Understanding the role of GPER in estrogen signaling may help resolve some of the controversies associated with estrogen and cardiovascular function. Moreover, a more thorough understanding of GPER function could also open significant opportunities for the development of new pharmacological strategies that would provide the cardiovascular benefits of estrogen while limiting the potentially dangerous side effects. PMID:23466742

Han, Guichun; Li, Fen; Yu, Xuan; White, Richard E

2013-05-01

323

From form to function: the role of Nox4 in the cardiovascular system  

PubMed Central

The NADPH oxidase (Nox) family of proteins is comprised of seven members, including Noxes1–5 and the Duoxes 1 and 2. Nox4 is readily distinguished from the other Nox isoforms by its high level of expression in cardiovascular tissues and unique enzymatic properties. Nox4 is constitutively active and the amount of reactive oxygen species (ROS) contributed by Nox4 is primarily regulated at the transcriptional level although there is recent evidence for post-translational control. Nox4 emits a different pattern of ROS and its subcellular localizations, tissue distribution and influence over signaling pathways is different from the other Nox enzymes. Previous investigations have revealed that Nox4 is involved in oxygen sensing, vasomotor control, cellular proliferation, differentiation, migration, apoptosis, senescence, fibrosis, and angiogenesis. Elevated expression of Nox4 has been reported in a number of cardiovascular diseases, including atherosclerosis, pulmonary fibrosis, and hypertension, cardiac failure and ischemic stroke. However, many important questions remain regarding the functional significance of Nox4 in health and disease, including the role of Nox4 subcellular localization and its downstream targets. The goal of this review is to summarize the recent literature on the genetic and enzymatic regulation, subcellular localization, signaling pathways, and the role of Nox4 in cardiovascular disease states. PMID:23125837

Chen, Feng; Haigh, Stephen; Barman, Scott; Fulton, David J. R.

2012-01-01

324

Kisspeptins: a multifunctional peptide system with a role in reproduction, cancer and the cardiovascular system  

PubMed Central

The pairing of the kisspeptins (KP) with the KISS1 (GPR54) receptor has received growing attention since the description of the receptor as a molecular switch for puberty. The role of KP and its receptor, GPR54, in puberty is the most exciting finding made in the field of reproductive biology since the discovery of Gonadotropin Releasing Hormone (GnRH) in 1970s. A significant body of evidence across several species now suggests that KISS1 (GPR54) activation is a critical point in the commencement of puberty, although further investigation is required to characterize the interaction between KP and GnRH cascade. Given such pivotal roles of kisspeptins and GPR54 as gatekeepers of reproductive function, and the proven ability of sex steroids to physiologically regulate this system, it is plausible that environmental compounds with ability to interfere oestrogen and/or androgen signaling (agonists or antagonists) may target the hypothalamic kiss-1/GPR54 system, thereby inducing functional alterations of the hypothalamic-pituitary-gonadal axis. Synthetic agonists targeting KISS1 (GPR54) may represent novel therapeutic agents for the treatment of hypogonadotrophic hypogonadism in some affected individuals. The diverse multifunctional nature of the KP is beginning to unravel. The unexpected role of these peptides in puberty has raised a number of important questions that remain to be answered. PMID:19554077

Votsi, E; Roussos, D; Katsikis, I; Karkanaki, A; Kita, M; Panidis, D

2008-01-01

325

Inhibiting C-Reactive Protein for the Treatment of Cardiovascular Disease: Promising Evidence from Rodent Models  

PubMed Central

Raised blood C-reactive protein (CRP) level is a predictor of cardiovascular events, but whether blood CRP is causal in the disease process is unknown. The latter would best be defined by pharmacological inhibition of the protein in the context of a randomized case-control study. However, no CRP specific drug is currently available so such a prospective study cannot be performed. Blood CRP is synthesized primarily in the liver and the liver is an organ where antisense oligonucleotide (ASO) drugs accumulate. Taking advantage of this we evaluated the efficacy of CRP specific ASOs in rodents with experimentally induced cardiovascular damage. Treating rats for 4 weeks with a rat CRP-specific ASO achieved >60% reduction of blood CRP. Notably, this effect was associated with improved heart function and pathology following myocardial infarction (induced by ligation of the left anterior descending artery). Likewise in human CRP transgenic mice treated for 2 weeks with a human CRP-specific ASO, blood human CRP was reduced by >70% and carotid artery patency was improved (2 weeks after surgical ligation). CRP specific ASOs might pave the way towards a placebo-controlled trial that could clarify the role of CRP in cardiovascular disease. PMID:24803739

Szalai, Alexander J.; McCrory, Mark A.; Xing, Dongqi; Hage, Fadi G.; Miller, Andrew; Oparil, Suzanne; Chen, Yiu-Fai; Mazzone, Michelle; Early, Richard; Henry, Scott P.; Zanardi, Thomas A.; Graham, Mark J.; Crooke, Rosanne M.

2014-01-01

326

Erythropoietin promotes deleterious cardiovascular effects and mortality risk in a rat model of chronic sports doping.  

PubMed

Athletes who abuse recombinant human erythropoietin (rhEPO) consider only the benefit to performance and usually ignore the potential short and long-term liabilities. Elevated haematocrit and dehydratation associated with intense exercise may reveal undetected cardiovascular risk, but the mechanisms underlying it remain to be fully explained. This study aimed to evaluate the cardiovascular effects of rhEPO in rats under chronic aerobic exercise. A ten week protocol was performed in four male Wistar rat groups: control--sedentary; rhEPO--50 IU kg(-1), 3 times/wk; exercised (EX)--swimming for 1 h, 3 times/wk; EX + rhEPO. One rat of the EX + rhEPO group suffered a sudden death episode during the week 8. rhEPO in trained rats promoted erythrocyte count increase, hypertension, heart hypertrophy, sympathetic and serotonergic overactivation. The suddenly died rat's tissues presented brain with vascular congestion; left ventricular hypertrophy, together with a "cardiac-liver", suggesting the hypothesis of heart failure as cause of sudden death. In conclusion, rhEPO doping in rats under chronic exercise promotes not only the expected RBC count increment, suggesting hyperviscosity, but also other serious deleterious cardiovascular and thromboembolic modifications, including mortality risk, which might be known and assumed by all sports authorities, including athletes and their physicians. PMID:19859831

Piloto, Nuno; Teixeira, Helena M; Teixeira-Lemos, Edite; Parada, Belmiro; Garrido, Patrícia; Sereno, José; Pinto, Rui; Carvalho, Lina; Costa, Elísio; Belo, Luís; Santos-Silva, Alice; Teixeira, Frederico; Reis, Flávio

2009-12-01

327

Aliskiren prevents cardiovascular complications and pancreatic injury in a mouse model of obesity and type 2 diabetes  

Microsoft Academic Search

Aims\\/hypothesis  The effect of renin inhibition on type 2 diabetes is still unclear. The present study was undertaken to examine the efficacy\\u000a of aliskiren, a direct renin inhibitor, on cardiovascular injuries, glucose intolerance and pancreatic injury in a mouse model\\u000a of type 2 diabetes.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Groups of db\\/db mice, with obesity and type 2 diabetes, were treated with aliskiren (3, 6, 12

Y. F. Dong; L. Liu; K. Kataoka; T. Nakamura; M. Fukuda; Y. Tokutomi; H. Nako; H. Ogawa; S. Kim-Mitsuyama

2010-01-01

328

The role of ATP-sensitive potassium channels in cellular function and protection in the cardiovascular system  

PubMed Central

ATP-sensitive potassium channels (KATP) are widely distributed and present in a number of tissues including muscle, pancreatic beta cells and the brain. Their activity is regulated by adenine nucleotides, characteristically being activated by falling ATP and rising ADP levels. Thus, they link cellular metabolism with membrane excitability. Recent studies using genetically modified mice and genomic studies in patients have implicated KATP channels in a number of physiological and pathological processes. In this review, we focus on their role in cellular function and protection particularly in the cardiovascular system. PMID:24102106

Tinker, Andrew; Aziz, Qadeer; Thomas, Alison

2014-01-01

329

Fluidic operational amplifier for mock circulatory systems  

Microsoft Academic Search

For the development of cardiovascular devices and the study of the dynamics of blood flow through the cardiovascular system, hardware fluidic models are commonly used to minimize animal experiments and clinical trials. These systems, called \\

Kwan-Woong Gwak; Brad E. Paden; James F. Antaki

2004-01-01

330

Fluidic operational amplifier for mock circulatory systems  

Microsoft Academic Search

For the development of cardiovascular devices and the study of the dynamics of blood flow through the cardiovascular system, hardware fluidic models are commonly used to minimize animal experiments and clinical trials. These systems, called \\

Kwan-Woong Gwak; Brad E. Paden; Myounggyu D. Noh; James F. Antaki

2006-01-01

331

MicroRNAs and Cardiovascular Diseases  

PubMed Central

MicroRNAs (miRNAs) are a class of small noncoding RNAs that have gained status as important regulators of gene expression. Recent studies have demonstrated that miRNAs are aberrantly expressed in the cardiovascular system under some pathological conditions. Gain- and loss-of-function studies using in vitro and in vivo models have revealed distinct roles for specific miRNAs in cardiovascular development and physiological function. The implications of miRNAs in cardiovascular disease have recently been recognized, representing the most rapidly evolving research field. In the present article, the currently relevant findings on the role of miRNAs in cardiac diseases will be updated and the target genes of these miRNAs are summarized. PMID:21395978

Ono, Koh; Kuwabara, Yasuhide; Han, Jiahuai

2011-01-01

332

Cardiovascular Effects of Erythropoietin: An Update  

PubMed Central

Erythropoietin (EPO) is a therapeutic product of recombinant DNA technology and it has been in clinical use as stimulator of erythropoiesis over the last two decades. Identification of EPO and its receptor (EPOR) in the cardiovascular system expanded understanding of physiological and pathophysiological role of EPO. In experimental models of cardiovascular and cerebrovascular disorders, EPO exerts protection by either preventing apoptosis of cardiac myocytes, smooth muscle cells, endothelial cells, or by increasing endothelial production of nitric oxide. In addition, EPO stimulates mobilization of progenitor cells from bone marrow thereby accelerating repair of injured endothelium and neovascularization. A novel signal transduction pathway involving EPOR - ?-common heteroreceptor is postulated to enhance EPO-mediated tissue protection. A better understanding of the role of ?-common receptor signaling as well as development of novel analogues of EPO with enhanced non-hematopoietic protective effects may expand clinical application of EPO in prevention and treatment of cardiovascular and cerebrovascular disorders. PMID:21081221

Santhanam, Anantha Vijay R.; d’Uscio, Livius V.; Katusic, Zvonimir S.

2014-01-01

333

Kisspeptins: a multifunctional peptide system with a role in reproduction, cancer and the cardiovascular system  

PubMed Central

Orphan G-protein-coupled receptors that have recently been paired with their cognate ligand are an often untapped resource for novel drug development. The KISS1 receptor (previously designated GPR54) has been paired with biologically active cleavage peptides of the KiSS-1 gene product, the kisspeptins (KP). The focus of this review is the emerging pharmacology and physiology of the KP. Genetic linkage analysis in humans revealed that mutations in KISS1 (GPR54, AXOR12 or hOT7T175) result in idiopathic hypogonadotrophic hypogonadism and knockout mouse studies confirmed this finding. Identification of KISS1 (GPR54) as a molecular switch for puberty subsequently led to the discovery that KP activate the GnRH cascade. Prior to the role of KISS1 (GPR54) in puberty being described, KP had been shown to be inhibitors of tumour metastasis across a range of cancers. Subsequently the mechanism of this inhibition has been suggested to be via altered cell motility and adhesiveness. PCR detected highest expression of KP and KISS1 (GPR54) in placenta, and changes in KP levels throughout pregnancy and expression in trophoblasts suggests a role in placentation. Placentation and metastasis are invasive processes that require angiogenesis. Investigation of KISS1 (GPR54) and KP in vasculature revealed discrete localisation of KISS1 (GPR54) to blood vessels prone to atherosclerosis and a potent vasoconstrictor action. A role for KP has also been shown in whole body homeostasis. KP are multifunctional peptides and further investigation is required to fully elucidate the complex pathways regulated by these peptides and how these pathways integrate in the whole body system. PMID:17519946

Mead, E J; Maguire, J J; Kuc, R E; Davenport, A P

2007-01-01

334

PPAR Agonists and Cardiovascular Disease in Diabetes  

PubMed Central

Peroxisome proliferators activated receptors (PPARs) are ligand-activated nuclear transcription factors that play important roles in lipid and glucose homeostasis. To the extent that PPAR agonists improve diabetic dyslipidaemia and insulin resistance, these agents have been considered to reduce cardiovascular risk. However, data from murine models suggests that PPAR agonists also have independent anti-atherosclerotic actions, including the suppression of vascular inflammation, oxidative stress, and activation of the renin angiotensin system. Many of these potentially anti-atherosclerotic effects are thought to be mediated by transrepression of nuclear factor-kB, STAT, and activator protein-1 dependent pathways. In recent clinical trials, PPAR? agonists have been shown to be effective in the primary prevention of cardiovascular events, while their cardiovascular benefit in patients with established cardiovascular disease remains equivocal. However, the use of PPAR? agonists, and more recently dual PPAR?/? coagonists, has been associated with an excess in cardiovascular events, possibly reflecting unrecognised fluid retention with potent agonists of the PPAR? receptor. Newer pan agonists, which retain their anti-atherosclerotic activity without weight gain, may provide one solution to this problem. However, the complex biologic effects of the PPARs may mean that only vascular targeted agents or pure transrepressors will realise the goal of preventing atherosclerotic vascular disease. PMID:18288280

Calkin, Anna C.; Thomas, Merlin C.

2008-01-01

335

[Effects of the 520-day isolation on the functional state of the cardiovascular system].  

PubMed

Purpose of the work was to study the cardiovascular effects of simulated factors in a 520-day crewed mission to Mars, and to validate the diagnostic value of the ultrasonic investigation of microcirculation and endothelium-dependent dilation of the right brachial artery in 6 male volunteers at the age of 28 to 39 years. It appears that 520-d isolation affected intracardiac hemodynamics and endothelium function more dramatically compared with 105-d isolation, increasing the risk of atherosclerosis. These findings add insight into the "cost of human adaptation" to very long isolation. PMID:25365873

Stepanova, G P; Bu?lov, S P; Eshchenko, A I; Skedina, M A; Voronkov, Iu I

2014-01-01

336

MicroRNAs in cardiovascular disease: from pathogenesis to prevention and treatment.  

PubMed

The management of cardiovascular risk through lifestyle modification and pharmacotherapy is paramount to the prevention of cardiovascular disease. Epidemiological studies have identified obesity, dyslipidemia, diabetes, and hypertension as interrelated factors that negatively affect cardiovascular health. Recently, genetic and pharmacological evidence in model systems has implicated microRNAs as dynamic modifiers of disease pathogenesis. An expanded understanding of the function of microRNAs in gene regulatory networks associated with cardiovascular risk will enable identification of novel genetic mechanisms of disease and inform the development of innovative therapeutic strategies. PMID:23281405

Quiat, Daniel; Olson, Eric N

2013-01-01

337

MicroRNAs in cardiovascular disease: from pathogenesis to prevention and treatment  

PubMed Central

The management of cardiovascular risk through lifestyle modification and pharmacotherapy is paramount to the prevention of cardiovascular disease. Epidemiological studies have identified obesity, dyslipidemia, diabetes, and hypertension as interrelated factors that negatively affect cardiovascular health. Recently, genetic and pharmacological evidence in model systems has implicated microRNAs as dynamic modifiers of disease pathogenesis. An expanded understanding of the function of microRNAs in gene regulatory networks associated with cardiovascular risk will enable identification of novel genetic mechanisms of disease and inform the development of innovative therapeutic strategies. PMID:23281405

Quiat, Daniel; Olson, Eric N.

2013-01-01

338

Cardiovascular Disease  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cardiovascular disease (CVD), particularly CHD (coronary heart disease) and stroke, remain the leading causes of death of women in America and most developed countries. In recent years the rate of CVD has declined in men but not in women. This is contributed to by an under-recognition of women’s C...

339

Beneficial Effect of Low Ethanol Intake on the Cardiovascular System: Possible Biochemical Mechanisms  

PubMed Central

Low ethanol intake is known to have a beneficial effect on cardiovascular disease. In cardiovascular disease, insulin resistance leads to altered glucose and lipid metabolism resulting in an increased production of aldehydes, including methylglyoxal. Aldehydes react non-enzymatically with sulfhydryl and amino groups of proteins forming advanced glycation end products (AGEs), altering protein structure and function. These alterations cause endothelial dysfunction with increased cytosolic free calcium, peripheral vascular resistance, and blood pressure. AGEs produce atherogenic effects including oxidative stress, platelet adhesion, inflammation, smooth muscle cell proliferation and modification of lipoproteins. Low ethanol intake attenuates hypertension and atherosclerosis but the mechanism of this effect is not clear. Ethanol at low concentrations is metabolized by low Km alcohol dehydrogenase and aldehyde dehydrogenase, both reactions resulting in the production of reduced nicotinamide adenine dinucleotide (NADH). This creates a reductive environment, decreasing oxidative stress and secondary production of aldehydes through lipid peroxidation. NADH may also increase the tissue levels of the antioxidants cysteine and glutathione, which bind aldehydes and stimulate methylglyoxal catabolism. Low ethanol improves insulin resistance, increases high-density lipoprotein and stimulates activity of the antioxidant enzyme, paraoxonase. In conclusion, we suggest that chronic low ethanol intake confers its beneficial effect mainly through its ability to increase antioxidant capacity and lower AGEs. PMID:17326332

Vasdev, Sudesh; Gill, Vicki; Singal, Pawan K

2006-01-01

340

Beneficial effect of low ethanol intake on the cardiovascular system: possible biochemical mechanisms.  

PubMed

Low ethanol intake is known to have a beneficial effect on cardiovascular disease. In cardiovascular disease, insulin resistance leads to altered glucose and lipid metabolism resulting in an increased production of aldehydes, including methylglyoxal. Aldehydes react non-enzymatically with sulfhydryl and amino groups of proteins forming advanced glycation end products (AGEs), altering protein structure and function. These alterations cause endothelial dysfunction with increased cytosolic free calcium, peripheral vascular resistance, and blood pressure. AGEs produce atherogenic effects including oxidative stress, platelet adhesion, inflammation, smooth muscle cell proliferation and modification of lipoproteins. Low ethanol intake attenuates hypertension and atherosclerosis but the mechanism of this effect is not clear. Ethanol at low concentrations is metabolized by low Km alcohol dehydrogenase and aldehyde dehydrogenase, both reactions resulting in the production of reduced nicotinamide adenine dinucleotide (NADH). This creates a reductive environment, decreasing oxidative stress and secondary production of aldehydes through lipid peroxidation. NADH may also increase the tissue levels of the antioxidants cysteine and glutathione, which bind aldehydes and stimulate methylglyoxal catabolism. Low ethanol improves insulin resistance, increases high-density lipoprotein and stimulates activity of the antioxidant enzyme, paraoxonase. In conclusion, we suggest that chronic low ethanol intake confers its beneficial effect mainly through its ability to increase antioxidant capacity and lower AGEs. PMID:17326332

Vasdev, Sudesh; Gill, Vicki; Singal, Pawan K

2006-01-01

341

Having a Change of Heart: A Lesson on Cardiovascular Anatomy  

NSDL National Science Digital Library

This teaching resource was developed by a K-12 science teacher in the American Physiologycal Society's 2006 Frontiers in Physiology Program. For more information on this program, please visit www.frontiersinphys.org. The purpose of this activity is to investigate and develop a model of the normal anatomy of the human heart/circulatory system and then to explore and model the effects of several cardiovascular disease processes. Students should understand basic cellular respiration. Upon completion of this activity, students will be able to: plan and design a model of a human heart with basic systemic circulation and evaluate impact of cardiovascular diseases on normal circulation.

Cynthia Pfirrmann (Scotch Plains-Fanwood High School)

2006-08-01

342

Communication system modeling  

NASA Technical Reports Server (NTRS)

This report presents the results of work on communications systems modeling and covers three different areas of modeling. The first of these deals with the modeling of signals in communication systems in the frequency domain and the calculation of spectra for various modulations. These techniques are applied in determining the frequency spectra produced by a unified carrier system, the down-link portion of the Command and Communications System (CCS). The second modeling area covers the modeling of portions of a communication system on a block basis. A detailed analysis and modeling effort based on control theory is presented along with its application to modeling of the automatic frequency control system of an FM transmitter. A third topic discussed is a method for approximate modeling of stiff systems using state variable techniques.

Holland, L. D.; Walsh, J. R., Jr.; Wetherington, R. D.

1971-01-01

343

ANALYSIS OF CARDIOVASCULAR REGULATION  

Microsoft Academic Search

Adequate characterization of hemodynamic and autonomic responses to physical and mental stress can elucidate underlying mechanisms of cardiovascular disease or anxiety disorders. We developed a physiological signal processing system for analysis of continuously recorded ECG, arterial blood pres- sure (BP), and respiratory signals using the programming language Matlab. Data collection devices are a 16-channel digital, physiological recorder (Vitaport), a finger

Frank H. Wilhelm; Paul Grossman; Walton T. Roth

1999-01-01

344

Model performance evaluation (validation and calibration) in model-based studies of therapeutic interventions for cardiovascular diseases : a review and suggested reporting framework.  

PubMed

Decision analytic models play an increasingly important role in the economic evaluation of health technologies. Given uncertainties around the assumptions used to develop such models, several guidelines have been published to identify and assess 'best practice' in the model development process, including general modelling approach (e.g., time horizon), model structure, input data and model performance evaluation. This paper focuses on model performance evaluation. In the absence of a sufficient level of detail around model performance evaluation, concerns regarding the accuracy of model outputs, and hence the credibility of such models, are frequently raised. Following presentation of its components, a review of the application and reporting of model performance evaluation is presented. Taking cardiovascular disease as an illustrative example, the review investigates the use of face validity, internal validity, external validity, and cross model validity. As a part of the performance evaluation process, model calibration is also discussed and its use in applied studies investigated. The review found that the application and reporting of model performance evaluation across 81 studies of treatment for cardiovascular disease was variable. Cross-model validation was reported in 55 % of the reviewed studies, though the level of detail provided varied considerably. We found that very few studies documented other types of validity, and only 6 % of the reviewed articles reported a calibration process. Considering the above findings, we propose a comprehensive model performance evaluation framework (checklist), informed by a review of best-practice guidelines. This framework provides a basis for more accurate and consistent documentation of model performance evaluation. This will improve the peer review process and the comparability of modelling studies. Recognising the fundamental role of decision analytic models in informing public funding decisions, the proposed framework should usefully inform guidelines for preparing submissions to reimbursement bodies. PMID:23456647

Haji Ali Afzali, Hossein; Gray, Jodi; Karnon, Jonathan

2013-04-01

345

Evaluation of the electromechanical properties of the cardiovascular system after prolonged weightlessness  

NASA Technical Reports Server (NTRS)

Devices and techniques for measuring and analyzing systolic time intervals and quantitative phonocardiograms were initiated during Apollo 17. The data show that the systolic time interval from Apollo 17 crewmen remained elevated longer postflight than the response criteria of heart rate, blood pressure, and percent change in leg volume all of which had returned to preflight levels by the second day postflight. Although the systolic time interval values were only slightly outside the preflight fiducial limits, this finding suggested that: the analysis of systolic time intervals may help to identify the mechanisms of postflight orthostatic intolerance by virtue of measuring ventricular function more directly and, the noninvasive technique may prove useful in determining the extent and duration of cardiovascular instability after long duration space flight. The systolic time intervals obtained on the Apollo 17 crewmen during lower body negative pressure were similar to those noted in patients with significant heart disease.

Bergman, S. A., Jr.; Johnson, R. L.; Hoffler, G. W.

1977-01-01

346

Mathematical circulatory system model  

NASA Technical Reports Server (NTRS)

A system and method of modeling a circulatory system including a regulatory mechanism parameter. In one embodiment, a regulatory mechanism parameter in a lumped parameter model is represented as a logistic function. In another embodiment, the circulatory system model includes a compliant vessel, the model having a parameter representing a change in pressure due to contraction of smooth muscles of a wall of the vessel.

Lakin, William D. (Inventor); Stevens, Scott A. (Inventor)

2010-01-01

347

Multiscale modelling of the circulatory system: a preliminary analysis  

Microsoft Academic Search

.   In this paper we show how numerical solutions of human cardiovascular system may be devised by coupling models having different\\u000a physical dimensions. One of the aspects of circulatory system is indeed its multiscale nature. Local flow features may have\\u000a a global effect on circulation. For instance, a stenosis caused by an atherosclerotic plaque may change the overall characteristic\\u000a of

Luca Formaggia; Fabio Nobile; Alfio Quarteroni; Alessandro Veneziani

1999-01-01

348

[Cardiovascular pharmacogenomics].  

PubMed

Cardiovascular disease remains a major cause of morbidity and mortality worldwide. Current medical practice takes into account information based on population studies and benefits observed in large populations or cohorts. However, individual patients present great differences in both toxicity and clinical efficacy that can be explained by variations in adherence, unknown drug to drug interactions and genetic variability. The latter seems to explain from 20% up to 95% of patient to patient variability. Treating patients with cardiovascular disorders faces the clinician with the challenge to include genomic analysis into daily practice. There are several examples within cardiovascular disease of treatments that can vary in toxicity or clinical usefulness based on genetic changes. One of the main factors affecting the efficacy of Clopidogrel is the phenotype associated with polymorphisms in the gene CYP 2C9. Furthermore, regarding oral anticoagulants, changes in CYP2C9 and VKORC1 play an important role in changing the clinical response to anticoagulation. When analyzing statin treatment, one of their main toxicities (myopathy) can be predicted by the SLCO1B1 polymorphism. The potential for prediction of toxicity and clinical efficacy from the use of genetic analysis warrants further studies aiming towards its inclusion in daily clinical practice. PMID:24636047

Scibona, Paula; Angriman, Federico; Simonovich, Ventura; Heller, Martina M; Belloso, Waldo H

2014-01-01

349

SMARTHealth India: Development and Field Evaluation of a Mobile Clinical Decision Support System for Cardiovascular Diseases in Rural India  

PubMed Central

Background Cardiovascular disease (CVD) is the major cause of premature death and disability in India and yet few people at risk of CVD are able to access best practice health care. Mobile health (mHealth) is a promising solution, but very few mHealth interventions have been subjected to robust evaluation in India. Objective The objectives were to develop a multifaceted, mobile clinical decision support system (CDSS) for CVD management and evaluate it for use by public nonphysician health care workers (NPHWs) and physicians in a rural Indian setting. Methods Plain language clinical rules were developed based on standard guidelines and programmed into a computer tablet app. The algorithm was validated and field-tested in 11 villages in Andhra Pradesh, involving 11 NPHWs and 3 primary health center (PHC) physicians. A mixed method evaluation was conducted comprising clinical and survey data and in-depth patient and staff interviews to understand barriers and enablers to the use of the system. Then this was thematically analyzed using NVivo 10. Results During validation of the algorithm, there was an initial agreement for 70% of the 42 calculated variables between the CDSS and SPSS software outputs. Discrepancies were identified and amendments were made until perfect agreement was achieved. During field testing, NPHWs and PHC physicians used the CDSS to screen 227 and 65 adults, respectively. The NPHWs identified 39% (88/227) of patients for referral with 78% (69/88) of these having a definite indication for blood pressure (BP)-lowering medication. However, only 35% (24/69) attended a clinic within 1 month of referral, with 42% (10/24) of these reporting continuing medications at 3-month follow-up. Physicians identified and recommended 17% (11/65) of patients for BP-lowering medications. Qualitative interviews identified 3 interrelated interview themes: (1) the CDSS had potential to change prevailing health care models, (2) task-shifting to NPHWs was the central driver of change, and (3) despite high acceptability by end users, actual transformation was substantially limited by system-level barriers such as patient access to doctors and medicines. Conclusions A tablet-based CDSS implemented within primary health care systems has the potential to help improve CVD outcomes in India. However, system-level barriers to accessing medical care limit its full impact. These barriers need to be actively addressed for clinical innovations to be successful. Trial Registration Clinical Trials Registry of India: CTRI/2013/06/003753; http://ctri.nic.in/Clinicaltrials/showallp.php?mid1=6259&EncHid=51761.70513&userName=CTRI/2013/06/003753 (Archived by WebCite at http://www.webcitation.org/6UBDlrEuq). PMID:25487047

Patel, Anushka; Raghu, Arvind; Clifford, Gari D; Maulik, Pallab K; Mohammad Abdul, Ameer; Mogulluru, Kishor; Tarassenko, Lionel; MacMahon, Stephen; Peiris, David

2014-01-01

350

Persistent Release of IL-1s from Skin Is Associated with Systemic Cardio-Vascular Disease, Emaciation and Systemic Amyloidosis: The Potential of Anti-IL-1 Therapy for Systemic Inflammatory Diseases  

PubMed Central

The skin is an immune organ that contains innate and acquired immune systems and thus is able to respond to exogenous stimuli producing large amount of proinflammatory cytokines including IL-1 and IL-1 family members. The role of the epidermal IL-1 is not limited to initiation of local inflammatory responses, but also to induction of systemic inflammation. However, association of persistent release of IL-1 family members from severe skin inflammatory diseases such as psoriasis, epidermolysis bullosa, atopic dermatitis, blistering diseases and desmoglein-1 deficiency syndrome with diseases in systemic organs have not been so far assessed. Here, we showed the occurrence of severe systemic cardiovascular diseases and metabolic abnormalities including aberrant vascular wall remodeling with aortic stenosis, cardiomegaly, impaired limb and tail circulation, fatty tissue loss and systemic amyloid deposition in multiple organs with liver and kidney dysfunction in mouse models with severe dermatitis caused by persistent release of IL-1s from the skin. These morbid conditions were ameliorated by simultaneous administration of anti-IL-1? and IL-1? antibodies. These findings may explain the morbid association of arteriosclerosis, heart involvement, amyloidosis and cachexia in severe systemic skin diseases and systemic autoinflammatory diseases, and support the value of anti-IL-1 therapy for systemic inflammatory diseases. PMID:25119884

Yamanaka, Keiichi; Nakanishi, Takehisa; Saito, Hiromitsu; Maruyama, Junko; Isoda, Kenichi; Yokochi, Ayumu; Imanaka-Yoshida, Kyoko; Tsuda, Kenshiro; Kakeda, Masato; Okamoto, Ryuji; Fujita, Satoshi; Iwakura, Yoichiro; Suzuki, Noboru; Ito, Masaaki; Maruyama, Kazuo; Gabazza, Esteban C.; Yoshida, Toshimichi; Shimaoka, Motomu; Mizutani, Hitoshi

2014-01-01

351

How mitochondrial dysfunction affects zebrafish development and cardiovascular function: an in vivo model for testing mitochondria-targeted drugs  

PubMed Central

Background and Purpose Mitochondria are a drug target in mitochondrial dysfunction diseases and in antiparasitic chemotherapy. While zebrafish is increasingly used as a biomedical model, its potential for mitochondrial research remains relatively unexplored. Here, we perform the first systematic analysis of how mitochondrial respiratory chain inhibitors affect zebrafish development and cardiovascular function, and assess multiple quinones, including ubiquinone mimetics idebenone and decylubiquinone, and the antimalarial atovaquone. Experimental Approach Zebrafish (Danio rerio) embryos were chronically and acutely exposed to mitochondrial inhibitors and quinone analogues. Concentration-response curves, developmental and cardiovascular phenotyping were performed together with sequence analysis of inhibitor-binding mitochondrial subunits in zebrafish versus mouse, human and parasites. Phenotype rescuing was assessed in co-exposure assays. Key Results Complex I and II inhibitors induced developmental abnormalities, but their submaximal toxicity was not additive, suggesting active alternative pathways for complex III feeding. Complex III inhibitors evoked a direct normal-to-dead transition. ATP synthase inhibition arrested gastrulation. Menadione induced hypochromic anaemia when transiently present following primitive erythropoiesis. Atovaquone was over 1000-fold less lethal in zebrafish than reported for Plasmodium falciparum, and its toxicity partly rescued by the ubiquinone precursor 4-hydroxybenzoate. Idebenone and decylubiquinone delayed rotenone- but not myxothiazol- or antimycin-evoked cardiac dysfunction. Conclusion and Implications This study characterizes pharmacologically induced mitochondrial dysfunction phenotypes in zebrafish, laying the foundation for comparison with future studies addressing mitochondrial dysfunction in this model organism. It has relevant implications for interpreting zebrafish disease models linked to complex I/II inhibition. Further, it evidences zebrafish's potential for in vivo efficacy or toxicity screening of ubiquinone analogues or antiparasitic mitochondria-targeted drugs. PMID:23758163

Pinho, Brígida R; Santos, Miguel M; Fonseca-Silva, Anabela; Valentão, Patrícia; Andrade, Paula B; Oliveira, Jorge M A

2013-01-01

352

A Functional Melanocortin System May Be Required for Chronic CNS-Mediated Antidiabetic and Cardiovascular Actions of Leptin  

PubMed Central

OBJECTIVE We recently showed that leptin has powerful central nervous system (CNS)-mediated antidiabetic and cardiovascular actions. This study tested whether the CNS melanocortin system mediates these actions of leptin in diabetic rats. RESEARCH DESIGN AND METHODS A cannula was placed in the lateral ventricle of Sprague-Dawley rats for intracerebroventricular infusions, and arterial and venous catheters were implanted to measure mean arterial pressure (MAP) and heart rate 24 h/day and for intravenous infusions. After recovery from surgery for 8 days, rats were injected with streptozotocin (STZ), and 5 days later, either saline or the melanocortin 3 and 4 receptor (MC3/4R) antagonist SHU-9119 (1 nmol/h) was infused intracerebroventricularly for 17 days. Seven days after starting the antagonist, leptin (0.62 ?g/h) was added to the intracerebroventricular infusion for 10 days. Another group of diabetic rats was infused with the MC3/4R agonist MTII (10 ng/h i.c.v.) for 12 days, followed by 7 days at 50 ng/h. RESULTS Induction of diabetes caused hyperphagia, hyperglycemia, and decreases in heart rate (?76 bpm) and MAP (?7 mmHg). Leptin restored appetite, blood glucose, heart rate, and MAP back to pre-diabetic values in vehicle-treated rats, whereas it had no effect in SHU-9119–treated rats. MTII infusions transiently reduced blood glucose and raised heart rate and MAP, which returned to diabetic values 5–7 days after starting the infusion. CONCLUSIONS Although a functional melanocortin system is necessary for the CNS-mediated antidiabetic and cardiovascular actions of leptin, chronic MC3/4R activation is apparently not sufficient to mimic these actions of leptin that may involve interactions of multiple pathways. PMID:19491210

da Silva, Alexandre A.; do Carmo, Jussara M.; Freeman, J. Nathan; Tallam, Lakshmi S.; Hall, John E.

2009-01-01

353

Systemic arterial baroreceptors in ducks and the consequences of their denervation on some cardiovascular responses to diving  

PubMed Central

1. In the duck systemic arterial baroreceptors which cause bradycardia in response to induced hypertension are located in the walls of the ascending aorta, innervated by the depressor nerves. 2. The location of the baroreceptors was confirmed both histologically and by recording activity from the depressor nerve. Stimulation of the central cut end of a depressor nerve caused transient bradycardia and a fall in blood pressure which was maintained throughout the period of stimulation. 3. Cardiovascular adjustments to submergence of 2 min duration were monitored in intact, sham-operated and denervated ducks. The sham-operated and denervated ducks were used in the experiments some 20-50 days post-operation. The denervations were checked at post-mortem. 4. In the first series of experiments on young ducks mean arterial pressure during a 2 min dive fell by 30% in intact, 17·5% in sham-operated, and 48% in denervated ducks. In all ducks heart rate was reduced by 84-85%. 5. In a second series of experiments on older ducks sciatic artery blood flow was also recorded and mean arterial blood pressure fell by 9·2% in intact and by 53% in denervated animals, although there were no significant differences in heart rate during the 2 min dives. In normal animals sciatic vascular resistance increased after 2 min submergence by 7·86 ± 1·7 times, whereas in denervated ducks it increased by only 2·32 ± 0·5 times. 6. The role of systemic arterial baroreceptors in generation of the cardiovascular responses to submergence in ducks is discussed in terms of the input supplied by the baroreceptors to the central nervous system. ImagesPlate 1 PMID:4764429

Jones, D. R.

1973-01-01

354

Cardiovascular Disease-Related Parameters and Oxidative Stress in SHROB Rats, a Model for Metabolic Syndrome  

PubMed Central

SHROB rats have been suggested as a model for metabolic syndrome (MetS) as a situation prior to the onset of CVD or type-2 diabetes, but information on descriptive biochemical parameters for this model is limited. Here, we extensively evaluate parameters related to CVD and oxidative stress (OS) in SHROB rats. SHROB rats were monitored for 15 weeks and compared to a control group of Wistar rats. Body weight was recorded weekly. At the end of the study, parameters related to CVD and OS were evaluated in plasma, urine and different organs. SHROB rats presented statistically significant differences from Wistar rats in CVD risk factors: total cholesterol, LDL-cholesterol, triglycerides, apoA1, apoB100, abdominal fat, insulin, blood pressure, C-reactive protein, ICAM-1 and PAI-1. In adipose tissue, liver and brain, the endogenous antioxidant systems were activated, yet there was no significant oxidative damage to lipids (MDA) or proteins (carbonylation). We conclude that SHROB rats present significant alterations in parameters related to inflammation, endothelial dysfunction, thrombotic activity, insulin resistance and OS measured in plasma as well as enhanced redox defence systems in vital organs that will be useful as markers of MetS and CVD for nutrition interventions. PMID:25115868

Molinar-Toribio, Eunice; Pérez-Jiménez, Jara; Ramos-Romero, Sara; Lluís, Laura; Sánchez-Martos, Vanessa; Taltavull, Núria; Romeu, Marta; Pazos, Manuel; Méndez, Lucía; Miranda, Aníbal; Cascante, Marta; Medina, Isabel; Torres, Josep Lluís

2014-01-01

355

The actions of the renin-angiotensin system on cardiovascular and osmoregulatory function in embryonic chickens (Gallus gallus domesticus).  

PubMed

Using embryonic chickens (Gallus gallus domesticus), we examined the role of the renin-angiotensin system (RAS) in cardiovascular and osmotic homeostasis through chronic captopril, an angiotensin-converting enzyme (ACE) inhibitor. Captopril (5mgkg(-1) embryo wet mass) or saline (control) was delivered via the egg air cell daily from embryonic day 5-18. Mean arterial pressure (MAP), heart rate (ƒH), fluid osmolality and ion concentration, and embryonic and organ masses were measured on day 19. Exogenous angiotensin I (ANG I) injection did not change MAP or ƒH in captopril-treated embryos, confirming ACE inhibition. Captopril-treated embryos were significantly hypotensive, with MAP 15% lower than controls, which we attributed to the loss of vasoconstrictive ANG II action. Exogenous ANG II induced a relatively greater hypertensive response in captopril-treated embryos compared to controls. Changes in response to ANG II following pre-treatment with phentolamine (?-adrenergic antagonist) indicated a portion of the ANG II response was due to circulating catecholamines in captopril-treated embryos. An increase in MAP and ƒH in response to hexamethonium indicated vagal tone was also increased in the absence of ACE activity. Captopril-treated embryos had lower osmolality, lower Na(+) and higher K(+) concentration in the blood, indicating osmoregulatory changes. Larger kidney mass in captopril-treated embryos suggests disrupting the RAS may stimulate kidney growth by decreasing resistance at the efferent arteriole and increasing the fraction of cardiac output to the kidneys. This study suggests that the RAS, most likely through ANG II action, influences the development of the cardiovascular and osmoregulatory systems. PMID:25149042

Mueller, Casey A; Crossley, Dane A; Burggren, Warren W

2014-12-01

356

Physiological regulation of pro-inflammatory cytokines expression in rat cardiovascular tissues by sympathetic nervous system and angiotensin II.  

PubMed

Pro-inflammatory cytokines regulation by sympathetic nervous system (SNS) and angiotensin II (ANG II) was widely described in cardiovascular system, but the role of such neuro-humoral interaction needs further investigation in this context. We tested SNS-ANG II interaction on IL-6 and TNF-? mRNA expression in left ventricle and aorta from normotensive rats by sympathectomy with guanethidine and blockade of the ANG II AT1 receptors (AT1R) antagonist with losartan. mRNA synthesis of IL-6 and TNF-? were performed by Q-RT-PCR. In the left ventricle, IL-6 mRNA increased by 63% (p < 0.01) after sympathectomy, still unchanged after losartan treatment and decreased by 38% (p < 0.05) after combined treatment. TNF-? mRNA decreased by 44% (p < 0.01), only after combined treatment. In the aorta, IL-6 mRNA increased equally by 65% (p < 0.05) after sympathectomy or losartan treatment. TNF-? mRNA decreased by 28, 41, and 42% (p < 0.05) after sympathectomy, losartan and combined treatments, respectively. Our data suggest that ANG II stimulates directly (via AT1R) and indirectly (via SNS) IL-6 mRNA synthesis in left ventricle and aorta and TNF-? mRNA in left ventricle. ANG II seems unable to influence directly TNF-? mRNA synthesis in the aorta but can stimulate this cytokine via SNS. The results are relevant to prevent or reduce proinflammatory cytokines overexpression seen in cardiovascular diseases. PMID:23846262

Dab, Houcine; Hachani, Rafik; Sakly, Mohsen; Bricca, Giampiero; Kacem, Kamel

2013-12-01

357

Exposure Analysis Modeling System  

EPA Science Inventory

The Exposure Analysis Modeling System (EXAMS) is an interactive software application for formulating aquatic ecosystem models and evaluating the fate, transport, and exposure concentrations of synthetic organic chemicals including pesticides, industrial materials, and leachates f...

358

Glyphosate-based herbicides potently affect cardiovascular system in mammals: review of the literature.  

PubMed

In glyphosate (G)-based herbicides (GBHs), the declared active principle G is mixed with several adjuvants that help it to penetrate the plants' cell membranes and its stabilization and liposolubility. Its utilization is growing with genetically modified organisms engineered to tolerate GBH. Millions of farmers suffer poisoning and death in developing countries, and occupational exposures and suicide make GBH toxicity a worldwide concern. As GBH is found in human plasma, widespread hospital facilities for measuring it should be encouraged. Plasma determination is an essential prerequisite for risk assessment in GBH intoxication. Only when standard ECGs were performed, at least one abnormal ECG was detected in the large majority of cases after intoxication. QTc prolongation and arrhythmias along with first-degree atrioventricular block were observed after GBH intoxication. Thus, life-threatening arrhythmias might be the cause of death in GBH intoxication. Cardiac cellular effects of GBH were reviewed along with few case reports in men and scanty larger studies. We observed in two mammalian species (rats and rabbits) direct cardiac electrophysiological changes, conduction blocks and arrhythmias among GBH-mediated effects. Plasmatic (and urine) level determinations of G and electrocardiographic Holter monitoring seem warranted to ascertain whether cardiovascular risk among agro-alimentary workers might be defined. PMID:25245870

Gress, Steeve; Lemoine, Sandrine; Séralini, Gilles-Eric; Puddu, Paolo Emilio

2015-04-01

359

The role of notch in the cardiovascular system: potential adverse effects of investigational notch inhibitors.  

PubMed

Targeting the Notch pathway is a new promising therapeutic approach for cancer patients. Inhibition of Notch is effective in the oncology setting because it causes a reduction of highly proliferative tumor cells and it inhibits survival of cancer stem cells, which are considered responsible for tumor recurrence and metastasis. Additionally, since Delta-like ligand 4 (Dll4)-activated Notch signaling is a major modulator of angiogenesis, anti-Dll4 agents are being investigated to reduce vascularization of the tumor. Notch plays a major role in the heart during the development and, after birth, in response to cardiac damage. Therefore, agents used to inhibit Notch in the tumors (gamma secretase inhibitors and anti-Dll4 agents) could potentially affect myocardial repair. The past experience with trastuzumab and other tyrosine kinase inhibitors used for cancer therapy demonstrates that the possible cardiotoxicity of agents targeting shared pathways between cancer and heart and the vasculature should be considered. To date, Notch inhibition in cancer patients has resulted only in mild gastrointestinal toxicity. Little is known about the potential long-term cardiotoxicity associated to Notch inhibition in cancer patients. In this review, we will focus on mechanisms through which inhibition of Notch signaling could lead to cardiomyocytes and endothelial dysfunctions. These adverse effects could contrast with the benefits of therapeutic responses in cancer cells during times of increased cardiac stress and/or in the presence of cardiovascular risk factor. PMID:25629006

Rizzo, Paola; Mele, Donato; Caliceti, Cristiana; Pannella, Micaela; Fortini, Cinzia; Clementz, Anthony George; Morelli, Marco Bruno; Aquila, Giorgio; Ameri, Pietro; Ferrari, Roberto

2014-01-01

360

The Role of Notch in the Cardiovascular System: Potential Adverse Effects of Investigational Notch Inhibitors  

PubMed Central

Targeting the Notch pathway is a new promising therapeutic approach for cancer patients. Inhibition of Notch is effective in the oncology setting because it causes a reduction of highly proliferative tumor cells and it inhibits survival of cancer stem cells, which are considered responsible for tumor recurrence and metastasis. Additionally, since Delta-like ligand 4 (Dll4)-activated Notch signaling is a major modulator of angiogenesis, anti-Dll4 agents are being investigated to reduce vascularization of the tumor. Notch plays a major role in the heart during the development and, after birth, in response to cardiac damage. Therefore, agents used to inhibit Notch in the tumors (gamma secretase inhibitors and anti-Dll4 agents) could potentially affect myocardial repair. The past experience with trastuzumab and other tyrosine kinase inhibitors used for cancer therapy demonstrates that the possible cardiotoxicity of agents targeting shared pathways between cancer and heart and the vasculature should be considered. To date, Notch inhibition in cancer patients has resulted only in mild gastrointestinal toxicity. Little is known about the potential long-term cardiotoxicity associated to Notch inhibition in cancer patients. In this review, we will focus on mechanisms through which inhibition of Notch signaling could lead to cardiomyocytes and endothelial dysfunctions. These adverse effects could contrast with the benefits of therapeutic responses in cancer cells during times of increased cardiac stress and/or in the presence of cardiovascular risk factor. PMID:25629006

Rizzo, Paola; Mele, Donato; Caliceti, Cristiana; Pannella, Micaela; Fortini, Cinzia; Clementz, Anthony George; Morelli, Marco Bruno; Aquila, Giorgio; Ameri, Pietro; Ferrari, Roberto

2015-01-01

361

What is next in nitric oxide research? From cardiovascular system to cancer biology.  

PubMed

The broad role of nitric oxide (NO) and cyclic GMP in biochemistry and biology as important messenger molecules is evident from the numerous publications in this research field. NO and cGMP have been known as components of the key signaling pathway in regulating numerous processes such as vascular dilation, blood pressure, neurotransmission, cardiovascular function, and renal function. In spite of almost 150,000 publications with nitric oxide and cyclic GMP, there are few publications regarding the effects of these messenger molecules on gene regulation, cell differentiation and cell proliferation. Our research data with embryonic stem cells and several cancer cell lines suggest that nitric oxide, its receptor soluble guanylyl cyclase (sGC) and sGC's product cyclic GMP can regulate the processes of proliferation and differentiation. Furthermore, we have found that undifferentiated stem cells and some malignant tumors such as human glioma have decreased levels of sGC and translocation of the sGC?1 subunit to the nucleus. We propose that sGC and cyclic GMP function as tumor suppressors. An understanding of the mechanisms of the translocation of the sGC?1 subunit into the nucleus and the possible regulation of gene expression of NO and/or cyclic CMP could lead to novel and innovative approaches to cancer therapy and stem cell proliferation and differentiation. PMID:25153032

Bian, Ka; Murad, Ferid

2014-12-01

362

Comparing Different Policy Scenarios to Reduce the Consumption of Ultra-Processed Foods in UK: Impact on Cardiovascular Disease Mortality Using a Modelling Approach  

PubMed Central

Background The global burden of non-communicable diseases partly reflects growing exposure to ultra-processed food products (UPPs). These heavily marketed UPPs are cheap and convenient for consumers and profitable for manufacturers, but contain high levels of salt, fat and sugars. This study aimed to explore the potential mortality reduction associated with future policies for substantially reducing ultra-processed food intake in the UK. Methods and Findings We obtained data from the UK Living Cost and Food Survey and from the National Diet and Nutrition Survey. By the NOVA food typology, all food items were categorized into three groups according to the extent of food processing: Group 1 describes unprocessed/minimally processed foods. Group 2 comprises processed culinary ingredients. Group 3 includes all processed or ultra-processed products. Using UK nutrient conversion tables, we estimated the energy and nutrient profile of each food group. We then used the IMPACT Food Policy model to estimate reductions in cardiovascular mortality from improved nutrient intakes reflecting shifts from processed or ultra-processed to unprocessed/minimally processed foods. We then conducted probabilistic sensitivity analyses using Monte Carlo simulation. Results Approximately 175,000 cardiovascular disease (CVD) deaths might be expected in 2030 if current mortality patterns persist. However, halving the intake of Group 3 (processed) foods could result in approximately 22,055 fewer CVD related deaths in 2030 (minimum estimate 10,705, maximum estimate 34,625). An ideal scenario in which salt and fat intakes are reduced to the low levels observed in Group 1 and 2 could lead to approximately 14,235 (minimum estimate 6,680, maximum estimate 22,525) fewer coronary deaths and approximately 7,820 (minimum estimate 4,025, maximum estimate 12,100) fewer stroke deaths, comprising almost 13% mortality reduction. Conclusions This study shows a substantial potential for reducing the cardiovascular disease burden through a healthier food system. It highlights the crucial importance of implementing healthier UK food policies. PMID:25679527

Moreira, Patricia V. L.; Baraldi, Larissa Galastri; Moubarac, Jean-Claude; Monteiro, Carlos Augusto; Newton, Alex; Capewell, Simon; O’Flaherty, Martin

2015-01-01

363

Preliminary Study of Cardiovascular Manifestations and Cardiac Severity Scale in 58 Patients with Systemic Sclerosis in Iran Using the Medsger Scale  

Microsoft Academic Search

Background: Cardiac involvement in systemic sclerosis (SSc) is more prevalent than previously thought. In this study, the frequency and severity of cardiovascular involvement were assessed in SSc patients referred to Firouzgar Hospital. Methods: Fifty-eight patients with SSc, selected from the data bank of SSc patients, were reviewed for the frequency and severity of 8 organ involvements in this case series.

Hadi Poormoghim; Mohamad Ali Poorkarim; Maziar Moradi Lakeh; Behnaz Nozary Heshmati; Simin Almasi; Mojtaba Hakim; Labafi-Nejad Hospital

364

Cardiovascular Engineering: An International Journal, Vol. 4, No. 1, March 2004 ( C 2004) Modeling Cerebral Blood Flow Control During Posture  

E-print Network

,, and JOHNNY OTTESEN Hypertension, decreased cerebral blood flow, and dimin- ished cerebral blood flow velocity-term cardiovascular regulation of blood flow to the brain is essential for development of new strategies to prevent in cardiovascular diseases such as hypertension (Aaslid, 1992; Strandgaard and Paulson, 1995; Traon et al., 2002

Olufsen, Mette Sofie

365

Wavelet transform coherence based investigation of existence of relationship between the cardiovascular and postural control systems during orthostatic challenge.  

PubMed

Previous studies have established the effects of orthostatic challenge on the cardiovascular and postural control systems, but the interdependent behavior of the systems under such condition is unclear. In the present study we examined the simultaneous changes in posture muscle electromyography (EMG) and systolic blood pressure (SBP) during quiet standing in healthy young individuals. Photoplethysmography based SBP, surface EMG, electrocardiogram (Lead II ECG) and posturography data were acquired during the experiment. Wavelet transform coherence (WTC) analysis was applied to identify the zones of interdependent behavior of the systems. The WTC thresholds were identified for the specific data under investigation. The coherence was analyzed in three frequency bands namely, LF (0.05 - 0.1 Hz), VLF (0.01-0.05 Hz) and ULF (0.005 - 0.01 Hz). WTC estimates for the EMG - SBP comparison showed greater than threshold values in all three frequency bands (LF: 0.31 ± 0.02; VLF: 0.41 ± 0.01; ULF: 0.45 ± 0.01). In conclusion this study showed the existence of relationship between the posture muscle EMG and blood pressure during natural orthostatic stress, by validation based on wavelet transform coherence. Further validation is required to objectively characterize this relationship between the two systems during orthostatic stress. PMID:23366703

Garg, Amanmeet; Blaber, Andrew P

2012-01-01

366

Genetic variants in serotonin and corticosteroid systems modulate neuroendocrine and cardiovascular responses to intense stress.  

PubMed

Common variants in serotonin and corticosteroid receptor genes influence human stress in laboratory settings. Little is known of their combined effects, especially in high stress environments. This study evaluated distinct and combined effects of polymorphisms in the serotonin transporter (5HTTLPRL/S), glucocorticoid receptor (Bcl1C/G), and mineralocorticoid (-2C/G) receptor genes on adrenocortical and cardiovascular responses to intense, realistic stress. One hundred and forty four healthy, active-duty military men were studied before, during, and 24h after a stressful 12-day survival course. Dependent variables were cortisol, heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP). 5HTTLPR SS carriers revealed higher overall cortisol concentrations than L carriers (p=.022). 5HTTLPR L carriers demonstrated higher stress-induced HR than non-carriers (SS) yet rebounded to a lower recovery value (p=.026), while Bcl1 G carriers showed higher mean stress-induced HR than non-carriers (CC) (p=.047). For DBP, 5HTTLPR S carriers showed higher overall values than non-carriers (LL) (p=.043), Bcl1 GG were higher than C carriers (p=.039), and -2C/G G carriers exceeded non-carriers (CC) (p=.028). A "high" composite genotype group revealed substantially higher overall cortisol concentrations than a "low" composite genotype group (p<.001), as was the case for DBP (p=.037). This study revealed a synergistic effect of common polymorphisms on the acute stress response in healthy men. Pending additional study, these findings may have implications for drug discovery, gene therapy, and stress inoculation strategies. PMID:24821403

Taylor, Marcus K; Larson, Gerald E; Lauby, Melissa D Hiller

2014-08-15

367

Virtual clay modeling system  

Microsoft Academic Search

This paper describes a CAD system in which a user can directly manipulate the shape of a virtual object like a clay model and can produce its solid model data. The key component of its hardware is a special input device with a 3D position tracker and a tactile sensor. In this system, the movement of a virtual object is

Ken-ichi Kameyama

1997-01-01

368

Cognitive Systems Cognitive Modeling  

E-print Network

1 Cognitive Systems Cognitive Modeling Foundations of Information Processing in Natural Barkowsky, Christian Freksa 2 Cognitive Systems: Topics · Introduction · Perception · Memory and Reasoning · Learning and Action · Communication · Empirical Methods 3 Cognitive Modeling: Topics · Cognitive

Bremen, Universität

369

Laser-scanning velocimetry: A confocal microscopy method for quantitative measurement of cardiovascular performance in zebrafish embryos and larvae  

Microsoft Academic Search

BACKGROUND: The zebrafish Danio rerio is an important model system for drug discovery and to study cardiovascular development. Using a laser-scanning confocal microscope, we have developed a non-invasive method of measuring cardiac performance in zebrafish embryos and larvae that obtains cardiovascular parameters similar to those obtained using Doppler echocardiography in mammals. A laser scan line placed parallel to the path

Michael H Malone; Noah Sciaky; Lisa Stalheim; Klaus M Hahn; Elwood Linney; Gary L Johnson

2007-01-01

370

38 CFR 4.104 - Schedule of ratings-cardiovascular system.  

Code of Federal Regulations, 2012 CFR

...symptomatic, evaluate according to body system affected. Following surgery, evaluate residuals under the body system affected. 7113Arteriovenous fistula...71 FR52460, Sept. 6, 2006] The Digestive...

2012-07-01

371

38 CFR 4.104 - Schedule of ratings-cardiovascular system.  

Code of Federal Regulations, 2013 CFR

...symptomatic, evaluate according to body system affected. Following surgery, evaluate residuals under the body system affected. 7113Arteriovenous fistula...71 FR52460, Sept. 6, 2006] The Digestive...

2013-07-01

372

38 CFR 4.104 - Schedule of ratings-cardiovascular system.  

Code of Federal Regulations, 2014 CFR

...symptomatic, evaluate according to body system affected. Following surgery, evaluate residuals under the body system affected. 7113Arteriovenous fistula...79 FR 2100, Jan. 13, 2014] The Digestive...

2014-07-01

373

38 CFR 4.104 - Schedule of ratings-cardiovascular system.  

Code of Federal Regulations, 2011 CFR

...symptomatic, evaluate according to body system affected. Following surgery, evaluate residuals under the body system affected. 7113Arteriovenous fistula...71 FR52460, Sept. 6, 2006] The Digestive...

2011-07-01

374

38 CFR 4.104 - Schedule of ratings-cardiovascular system.  

Code of Federal Regulations, 2010 CFR

...symptomatic, evaluate according to body system affected. Following surgery, evaluate residuals under the body system affected. 7113Arteriovenous fistula...71 FR52460, Sept. 6, 2006] The Digestive...

2010-07-01

375

Therapeutic manipulation of glucocorticoid metabolism in cardiovascular disease  

PubMed Central

The therapeutic potential for manipulation of glucocorticoid metabolism in cardiovascular disease was revolutionized by the recognition that access of glucocorticoids to their receptors is regulated in a tissue-specific manner by the isozymes of 11?-hydroxysteroid dehydrogenase. Selective inhibitors of 11?-hydroxysteroid dehydrogenase type 1 have been shown recently to ameliorate cardiovascular risk factors and inhibit the development of atherosclerosis. This article addresses the possibility that inhibition of 11?-hydroxsteroid dehydrogenase type 1 activity in cells of the cardiovascular system contributes to this beneficial action. The link between glucocorticoids and cardiovascular disease is complex as glucocorticoid excess is linked with increased cardiovascular events but glucocorticoid administration can reduce atherogenesis and restenosis in animal models. There is considerable evidence that glucocorticoids can interact directly with cells of the cardiovascular system to alter their function and structure and the inflammatory response to injury. These actions may be regulated by glucocorticoid and/or mineralocorticoid receptors but are also dependent on the 11?-hydroxysteroid dehydrogenases which may be expressed in cardiac, vascular (endothelial, smooth muscle) and inflammatory (macrophages, neutrophils) cells. The activity of 11?-hydroxysteroid dehydrogenases in these cells is dependent upon differentiation state, the action of pro-inflammaotory cytokines and the influence of endogenous inhibitors (oxysterols, bile acids). Further investigations are required to clarify the link between glucocorticoid excess and cardiovascular events and to determine the mechanism through which glucocorticoid treatment inhibits atherosclerosis/restenosis. This will provide greater insights into the potential benefit of selective 11?-hydroxysteroid dehydrogenase inhibitors in treatment of cardiovascular disease. PMID:19239478

Hadoke, Patrick WF; Iqbal, Javaid; Walker, Brian R

2009-01-01

376

Instrumentation for Non-Invasive Assessment of Cardiovascular Regulation  

NASA Technical Reports Server (NTRS)

It is critically important to be able to assess alterations in cardiovascular regulation during and after space flight. We propose to develop an instrument for the non-invasive assessment of such alterations that can be used on the ground and potentially during space flight. This instrumentation would be used by the Cardiovascular Alterations Team at multiple sites for the study of the effects of space flight on the cardiovascular system and the evaluation of countermeasures. In particular, the Cardiovascular Alterations Team will use this instrumentation in conjunction with ground-based human bed-rest studies and during application of acute stresses e.g., tilt, lower body negative pressure, and exercise. In future studies, the Cardiovascular Alterations Team anticipates using this instrumentation to study astronauts before and after space flight and ultimately, during space flight. The instrumentation may also be used by the Bone Demineralization/Calcium Metabolism Team, the Neurovestibular Team and the Human Performance Factors, Sleep and Chronobiology Team to measure changes in autonomic nervous function. The instrumentation will be based on a powerful new technology - cardiovascular system identification (CSI) - which has been developed in our laboratory. CSI provides a non-invasive approach for the study of alterations in cardiovascular regulation. This approach involves the analysis of second-to-second fluctuations in physiologic signals such as heart rate and non-invasively measured arterial blood pressure in order to characterize quantitatively the physiologic mechanisms responsible for the couplings between these signals. Through the characterization of multiple physiologic mechanisms, CSI provides a closed-loop model of the cardiovascular regulatory state in an individual subject.

Cohen, Richard J.

1999-01-01

377

Fluidic operational amplifier for mock circulatory systems - simulation and experimental results  

Microsoft Academic Search

For the development of cardiovascular devices and the study of the dynamics of blood flow through the cardiovascular system, hardware fluidic models are commonly used to minimize animal experiments and clinical trials. These systems, called \\

Kwan-Woong Gwak; Myounggyu D. Noh; Brad E. Paden; James F. Antaki

2005-01-01

378

Genetic manipulation and genetic variation of the kallikrein-kinin system: impact on cardiovascular and renal diseases.  

PubMed

Genetic manipulation of the kallikrein-kinin system (KKS) in mice, with either gain or loss of function, and study of human genetic variability in KKS components which has been well documented at the phenotypic and genomic level, have allowed recognizing the physiological role of KKS in health and in disease. This role has been especially documented in the cardiovascular system and the kidney. Kinins are produced at slow rate in most organs in resting condition and/or inactivated quickly. Yet the KKS is involved in arterial function and in renal tubular function. In several pathological situations, kinin production increases, kinin receptor synthesis is upregulated, and kinins play an important role, whether beneficial or detrimental, in disease outcome. In the setting of ischemic, diabetic or hemodynamic aggression, kinin release by tissue kallikrein protects against organ damage, through B2 and/or B1 bradykinin receptor activation, depending on organ and disease. This has been well documented for the ischemic or diabetic heart, kidney and skeletal muscle, where KKS activity reduces oxidative stress, limits necrosis or fibrosis and promotes angiogenesis. On the other hand, in some pathological situations where plasma prekallikrein is inappropriately activated, excess kinin release in local or systemic circulation is detrimental, through oedema or hypotension. Putative therapeutic application of these clinical and experimental findings through current pharmacological development is discussed in the chapter. PMID:25130042

Girolami, Jean-Pierre; Blaes, Nelly; Bouby, Nadine; Alhenc-Gelas, François

2014-01-01

379

The Earth System Model  

NASA Technical Reports Server (NTRS)

The Earth System Model is the natural evolution of current climate models and will be the ultimate embodiment of our geophysical understanding of the planet. These models are constructed from components - atmosphere, ocean, ice, land, chemistry, solid earth, etc. models and merged together through a coupling program which is responsible for the exchange of data from the components. Climate models and future earth system models will have standardized modules, and these standards are now being developed by the ESMF project funded by NASA. The Earth System Model will have a variety of uses beyond climate prediction. The model can be used to build climate data records making it the core of an assimilation system, and it can be used in OSSE experiments to evaluate. The computing and storage requirements for the ESM appear to be daunting. However, the Japanese ES theoretical computing capability is already within 20% of the minimum requirements needed for some 2010 climate model applications. Thus it seems very possible that a focused effort to build an Earth System Model will achieve succcss.

Schoeberl, Mark; Rood, Richard B.; Hildebrand, Peter; Raymond, Carol

2003-01-01

380

Interventional cardiovascular magnetic resonance imaging  

PubMed Central

Magnetic resonance imaging (MRI) provides structural and functional cardiovascular information with excellent soft tissue contrast. Real-time MRI can guide transcatheter cardiovascular interventions in large animal models, and may prove superior to x-ray and adjunct modalities for peripheral vascular, structural heart and cardiac electrophysiology applications. We describe technical considerations, pre-clinical work and early clinical studies in this emerging field. PMID:17662914

Raman, Venkatesh K.; Lederman, Robert J.

2008-01-01

381

Model-Based Systems  

NASA Technical Reports Server (NTRS)

Engineers, who design systems using text specification documents, focus their work upon the completed system to meet Performance, time and budget goals. Consistency and integrity is difficult to maintain within text documents for a single complex system and more difficult to maintain as several systems are combined into higher-level systems, are maintained over decades, and evolve technically and in performance through updates. This system design approach frequently results in major changes during the system integration and test phase, and in time and budget overruns. Engineers who build system specification documents within a model-based systems environment go a step further and aggregate all of the data. They interrelate all of the data to insure consistency and integrity. After the model is constructed, the various system specification documents are prepared, all from the same database. The consistency and integrity of the model is assured, therefore the consistency and integrity of the various specification documents is insured. This article attempts to define model-based systems relative to such an environment. The intent is to expose the complexity of the enabling problem by outlining what is needed, why it is needed and how needs are being addressed by international standards writing teams.

Frisch, Harold P.

2007-01-01

382

EB 2010 Refresher Course - Cardiovascular Physiology  

NSDL National Science Digital Library

Cardiovascular physiology is one of the basics of a medical school course. This area is very complex is a basis for the first year physiology and the clinical medicine. The intent of this refresher course is to bring together a cadre of instructors with extensive knowledge and experience in teaching cardiovascular physiology. Not only will this benefit instructors assigned to teach cardiovascular physiology, but it can also benefit those interested in understanding the topic better. The most fundamental aspects of cardiovascular physiology will be covered in this refresher course, including: Cardiac Function, Local Control of Blood Flow, Neural Control of Circulation and the Integrative Cardiovascular Physiology. By establishing a solid grounding in cardiovascular physiology, one can only enhance the perspective of students as they examine specific processes relevant to cardiovascular physiology at a systems level.

PhD Donna H. Korzick (Pennsylvania State University Dept. of Physiology and Kinesiology)

2010-04-01

383

Inhibitors of the complement system currently in development for cardiovascular disease  

Microsoft Academic Search

Controlled activation of the complement system is critical to the host-defense response of the immune system. Activated complement\\u000a is responsible for the stimulation of a localized protective inflammatory response to either invading microorganisms or foreign\\u000a molecules (toxins). However, the autologous activation of the complement system can have devastating conseuences on many organ\\u000a systems. This review discusses the various pathways involved

M. K. Pugsley; M. Abramova; T. Cole; X. Yang; W. S. Ammons

2003-01-01

384

Developmental Programming of Cardiovascular Disease Following Intrauterine Growth Restriction: Findings Utilising A Rat Model of Maternal Protein Restriction  

PubMed Central

Over recent years, studies have demonstrated links between risk of cardiovascular disease in adulthood and adverse events that occurred very early in life during fetal development. The concept that there are embryonic and fetal adaptive responses to a sub-optimal intrauterine environment often brought about by poor maternal diet that result in permanent adverse consequences to life-long health is consistent with the definition of “programming”. The purpose of this review is to provide an overview of the current knowledge of the effects of intrauterine growth restriction (IUGR) on long-term cardiac structure and function, with particular emphasis on the effects of maternal protein restriction. Much of our recent knowledge has been derived from animal models. We review the current literature of one of the most commonly used models of IUGR (maternal protein restriction in rats), in relation to birth weight and postnatal growth, blood pressure and cardiac structure and function. In doing so, we highlight the complexity of developmental programming, with regards to timing, degree of severity of the insult, genotype and the subsequent postnatal phenotype. PMID:25551250

Zohdi, Vladislava; Lim, Kyungjoon; Pearson, James T.; Black, M. Jane

2014-01-01

385

Tyrosine nitration of PA700 links proteasome activation to endothelial dysfunction in mouse models with cardiovascular risk factors.  

PubMed

Oxidative stress is believed to cause endothelial dysfunction, an early event and a hallmark in cardiovascular diseases (CVD) including hypertension, diabetes, and dyslipidemia. However, the targets for oxidative stress-mediated endothelial dysfunction in CVD have not been completely elucidated. Here we report that 26S proteasome activation by peroxynitrite (ONOO(-)) is a common pathway for endothelial dysfunction in mouse models of diabetes, hypertension, and dyslipidemia. Endothelial function, assayed by acetylcholine-induced vasorelaxation, was impaired in parallel with significantly increased 26S proteasome activity in aortic homogenates from streptozotocin (STZ)-induced type I diabetic mice, angiotensin-infused hypertensive mice, and high fat-diets-fed LDL receptor knockout (LDLr(-/-)) mice. The elevated 26S proteasome activities were accompanied by ONOO(-)-mediated PA700/S10B nitration and increased 26S proteasome assembly and caused accelerated degradation of molecules (such as GTPCH I and thioredoxin) essential to endothelial homeostasis. Pharmacological (administration of MG132) or genetic inhibition (siRNA knockdown of PA700/S10B) of the 26S proteasome blocked the degradation of the vascular protective molecules and ablated endothelial dysfunction induced by diabetes, hypertension, and western diet feeding. Taken together, these results suggest that 26S proteasome activation by ONOO(-)-induced PA700/S10B tyrosine nitration is a common route for endothelial dysfunction seen in mouse models of hypertension, diabetes, and dyslipidemia. PMID:22272240

Xu, Jian; Wang, Shuangxi; Zhang, Miao; Wang, Qilong; Asfa, Sima; Zou, Ming-Hui

2012-01-01

386

Tyrosine Nitration of PA700 Links Proteasome Activation to Endothelial Dysfunction in Mouse Models with Cardiovascular Risk Factors  

PubMed Central

Oxidative stress is believed to cause endothelial dysfunction, an early event and a hallmark in cardiovascular diseases (CVD) including hypertension, diabetes, and dyslipidemia. However, the targets for oxidative stress-mediated endothelial dysfunction in CVD have not been completely elucidated. Here we report that 26S proteasome activation by peroxynitrite (ONOO?) is a common pathway for endothelial dysfunction in mouse models of diabetes, hypertension, and dyslipidemia. Endothelial function, assayed by acetylcholine-induced vasorelaxation, was impaired in parallel with significantly increased 26S proteasome activity in aortic homogenates from streptozotocin (STZ)-induced type I diabetic mice, angiotensin-infused hypertensive mice, and high fat-diets -fed LDL receptor knockout (LDLr?/?) mice. The elevated 26S proteasome activities were accompanied by ONOO?-mediated PA700/S10B nitration and increased 26S proteasome assembly and caused accelerated degradation of molecules (such as GTPCH I and thioredoxin) essential to endothelial homeostasis. Pharmacological (administration of MG132) or genetic inhibition (siRNA knockdown of PA700/S10B) of the 26S proteasome blocked the degradation of the vascular protective molecules and ablated endothelial dysfunction induced by diabetes, hypertension, and western diet feeding. Taken together, these results suggest that 26S proteasome activation by ONOO?-induced PA700/S10B tyrosine nitration is a common route for endothelial dysfunction seen in mouse models of hypertension, diabetes, and dyslipidemia. PMID:22272240

Xu, Jian; Wang, Shuangxi; Zhang, Miao; Wang, Qilong; Asfa, Sima; Zou, Ming-Hui

2012-01-01

387

Time-accurate, parallel, multi-zone, multi-block solver to study the human cardio-vascular system.  

PubMed

A parallel, time-accurate flow solver is devised to study the human cardio-vascular system. The solver is capable of dealing with moving boundaries and moving grids. It is designed to handle complex, three-dimensional vascular systems. The computational domain is divided into multiple block subdomains. At each cross section the plane is divided into twelve sub-zones to allow flexibility for handling complex geometries and, if needed, appropriate parallel data partitioning. The unsteady, three-dimensional, incompressible Navier-Stokes equations are solved numerically. A second-order in time and third-order upwind finite volume method for solving time-accurate incompressible flows based on pseudo-compressibility and dual time-stepping technique is used. For parallel execution, the flow domain is partitioned. Communication between the subdomains of the flow on Riken's VPP/700E supercomputer is implemented using MPI message-passing library. A series of numerical simulations of biologically relevant flows is used to validate this code. PMID:12122256

Tadjfar, Mehran; Himeno, Ryutaro

2002-01-01

388

Sharing risk management: an implementation model for cardiovascular absolute risk assessment and management in Australian general practice  

PubMed Central

Purpose Despite considerable work in developing and validating cardiovascular absolute risk (CVAR) algorithms, there has been less work on models for their implementation in assessment and management. The aim of our study was to develop a model for a joint approach to its implementation based on an exploration of views of patients, general practitioners (GPs) and key informants (KIs). Methods We conducted six focus group (three with GPs and three with patients) and nine KI interviews in Sydney. Thematic analysis was used with comparison to highlight the similarities and differences in perspectives of participants. Results Conducting CVAR was seen as more acceptable for regular patients rather than new patients for whom GPs had to attract their interest and build rapport before doing so at the next visit. GPs’ interest and patients’ positive attitude in managing risk were important in implementing CVAR. Long consultations, good communication skills and having a trusting relationship helped overcome the barriers during the process. All the participants supported engaging patients to self-assess their risk before the consultation and sharing decision making with GPs during consultation. Involving practice staff to help with the patient self-assessment, follow-up and referral would be helpful in implementing CVAR assessment and management, but GPs, patients and practices may need more support for this to occur. Conclusions Multiple strategies are required to promote the better use of CVAR in the extremely busy working environment of Australian general practice. An implementation model has been developed based on our findings and the Chronic Care Model. Further research needs to investigate the effectiveness of the proposed model. PMID:18479283

Wan, Q; Harris, M F; Zwar, N; Vagholkar, S

2008-01-01

389

SYSTEMIC BIOMARKERS AND CARDIAC GENE EXPRESSION PROFILES OF RAT DISEASE MODELS EMPLOYED IN AIR POLLUTION STUDIES  

EPA Science Inventory

Cardiovascular disease (CVD) models are used for identification of mechanisms of susceptibility to air pollution. We hypothesized that baseline systemic biomarkers and cardiac gene expression in CVD rat models will have influence on their ozone-induced lung inflammation. Male 12-...

390

Large Scale Expansion of Human Umbilical Cord Cells in a Rotating Bed System Bioreactor for Cardiovascular Tissue Engineering Applications  

PubMed Central

Widespread use of human umbilical cord cells for cardiovascular tissue engineering requires production of large numbers of well-characterized cells under controlled conditions. In current research projects, the expansion of cells to be used to create a tissue construct is usually performed in static cell culture systems which are, however, often not satisfactory due to limitations in nutrient and oxygen supply. To overcome these limitations dynamic cell expansion in bioreactor systems under controllable conditions could be an important tool providing continuous perfusion for the generation of large numbers of viable pre-conditioned cells in a short time period. For this purpose cells derived from human umbilical cord arteries were expanded in a rotating bed system bioreactor for up to 9 days. For a comparative study, cells were cultivated under static conditions in standard culture devices. Our results demonstrated that the microenvironment in the perfusion bioreactor was more favorable than that of the standard cell culture flasks. Data suggested that cells in the bioreactor expanded 39 fold (38.7 ± 6.1 fold) in comparison to statically cultured cells (31.8 ± 3.0 fold). Large-scale production of cells in the bioreactor resulted in more than 3 x 108 cells from a single umbilical cord fragment within 9 days. Furthermore cell doubling time was lower in the bioreactor system and production of extracellular matrix components was higher. With this study, we present an appropriate method to expand human umbilical cord artery derived cells with high cellular proliferation rates in a well-defined bioreactor system under GMP conditions. PMID:23847691

Reichardt, Anne; Polchow, Bianca; Shakibaei, Mehdi; Henrich, Wolfgang; Hetzer, Roland; Lueders, Cora

2013-01-01

391

MODELLING OF HEATING SYSTEMS  

Microsoft Academic Search

Measurement and control of technological processes is important for projecting of buildings and equipments. The quality and effectivity of control systems is rising with help of simulation environments. We have decided to use products of The MathWorks, Matlab\\/Simulink and Matlab\\/SimScape for modeling of heating systems. Matlab\\/SimScape libraries contain special blocks for modeling hydraulic, thermal and mechanical components, which has been

Andrea Pavlúsová; Martin Foltin; Martin Ernek

392

Cardiovascular adaptation to spaceflight  

NASA Technical Reports Server (NTRS)

Data are presented on the rate of adaptation of the human cardiovascular system to conditions of spaceflight, with particular attention given to data obtained during spaceflight in the U.S. Space Shuttle Program. It is pointed out that many of the cardiovascular changes that occurred during spaceflights that lasted from 2 to 11 days can be traced directly to changes in the body fluid volume. The beneficial effects of a fluid loading countermeasure (oral rehydration) and of the supine body position on the heart rate during the spaceflight are demonstrated. It is noted that, after hours or a few days of spaceflight, a state of adaptation is reached, in which the subject is well adapted and appropriately hydrated for the weightless environment. However, the return to the normal gravity of the earth leaves the individual especially sensitive to orthostatic stress.

Charles, John B.; Lathers, Claire M.

1991-01-01

393

Rat Models of Cardiovascular Disease Demonstrate Distinctive Pulmonary Gene Expressions for Vascular Response Genes: Impact of Ozone Exposure  

EPA Science Inventory

Comparative gene expression profiling of multiple tissues from rat strains with genetic predisposition to diverse cardiovascular diseases (CVD) can help decode the transcriptional program that governs organ-specific functions. We examined expressions of CVD genes in the lungs of ...

394

Pulmonary Toxicity and Modifications in Iron Homeostasis Following Libby Amphibole Asbestos Exposure in Rat Models of Cardiovascular Disease  

EPA Science Inventory

Rationale: Individuals suffering from cardiovascular disease (CVD) develop iron dysregulation which may influence pulmonary toxicity and injury upon exposure to asbestos. We hypothesized spontaneously hypertensive (SH) and spontaneously hypertensive heart failure (SHHF) rats woul...

395

119MARCH 2010 NEW BIOLOGICAL BOOKS on pigmentation, cardiovascular systems, swimming,  

E-print Network

on environmental and nutritional problems. Each contribution is written by separate authors, all ofwhich in Vertebrates. Edited by Maria Ogielska. Enfield (New Hampshire): Science Publishers. $125.00. xiv + 422 p.; ill Systems in Vertebrates. Previous volumes have dealt with respiratory, renal, and muscular systems

Sever, David M.

396

77 FR 8117 - Medical Devices; Cardiovascular Devices; Classification of the Endovascular Suturing System  

Federal Register 2010, 2011, 2012, 2013, 2014

...fixation and sealing between an endovascular graft and the native artery. The system is comprised of the implant device and an endovascular...fixation and sealing between an endovascular graft and the native artery. The system is comprised of the implant device and an...

2012-02-14

397

Classification of low systemic vascular resistance using photoplethysmogram and routine cardiovascular measurements  

Microsoft Academic Search

Low systemic vascular resistance (SVR) can be a useful indicator for early diagnosis of critical pathophysiological conditions such as sepsis, and the ability to identify low SVR from simple and noninvasive physiological signals is of immense clinical value. In this study, an SVR classification system is presented to recognize the occurrence of low SVR, among a heterogenous group of patients

Qim Y. Lee; Gregory S. H. Chan; Stephen J. Redmond; P. M. Middleton; E. Steel; P. Malouf; C. Critoph; G. Flynn; E. O'Lone; Nigel H. Lovell

2010-01-01

398

Calibrating Water System Models  

Microsoft Academic Search

Calibration enables a computer model to simulate field conditions accurately. Telemetry data and field measurements of the system provide base data for calibration, but computer programs that automatically extract and compare pertinent data with simulated values can aid the process. Once calibrated, the model can be used with a great degree of confidence as a predictor and as a benchmark

A. Lee Cesario; J. O. Davis

1984-01-01

399

Applicability of the polynomial chaos expansion method for personalization of a cardiovascular pulse wave propagation model.  

PubMed

Patient-specific modeling requires model personalization, which can be achieved in an efficient manner by parameter fixing and parameter prioritization. An efficient variance-based method is using generalized polynomial chaos expansion (gPCE), but it has not been applied in the context of model personalization, nor has it ever been compared with standard variance-based methods for models with many parameters. In this work, we apply the gPCE method to a previously reported pulse wave propagation model and compare the conclusions for model personalization with that of a reference analysis performed with Saltelli's efficient Monte Carlo method. We furthermore differentiate two approaches for obtaining the expansion coefficients: one based on spectral projection (gPCE-P) and one based on least squares regression (gPCE-R). It was found that in general the gPCE yields similar conclusions as the reference analysis but at much lower cost, as long as the polynomial metamodel does not contain unnecessary high order terms. Furthermore, the gPCE-R approach generally yielded better results than gPCE-P. The weak performance of the gPCE-P can be attributed to the assessment of the expansion coefficients using the Smolyak algorithm, which might be hampered by the high number of model parameters and/or by possible non-smoothness in the output space. PMID:25377937

Huberts, W; Donders, W P; Delhaas, T; van de Vosse, F N

2014-12-01

400

Relationship of Paraoxonase 1 (PON1) Gene Polymorphisms and Functional Activity With Systemic Oxidative Stress and Cardiovascular Risk  

PubMed Central

Context Paraoxonase 1 (PON1) is reported to have antioxidant and cardioprotective properties. The relationship between PON1 genotypes and functional activity with systemic measures of oxidative stress and cardiovascular disease (CVD) risk in humans has not been systematically investigated. Objective To investigate the relationship of genetic and biochemical determinants of PON1 activity with systemic measures of oxidative stress and CVD risk in humans. Design, Setting, and Participants The association between systemic PON1 activity measures and a functional polymorphism (Q192R) resulting in high PON1 activity with prevalent CVD and future major adverse cardiac events (myocardial infarction, stroke, or death) was evaluated in 1399 sequential consenting patients undergoing diagnostic coronary angiography between September 2002 and November 2003 at the Cleveland Clinic. Patients were followed up until December 2006. Systemic levels of multiple structurally defined fatty acid oxidation products were also measured by mass spectrometry in 150 age-, sex-, and race-matched patients and compared with regard to PON1 genotype and activity. Main Outcome Measures Relationship between a functional PON1 polymorphism and PON1 activity with global indices of systemic oxidative stress and risk of CVD. Results The PON1 genotype demonstrated significant dose-dependent associations (QQ192>QR192>RR192) with decreased levels of serum PON1 activity and with increased levels of systemic indices of oxidative stress. Compared with participants with either the PON1 RR192 or QR192 genotype, participants with the QQ192 genotype demonstrated an increased risk of all-cause mortality (43/681 deaths [6.75%] in RR192 and QR192 and 62/584 deaths [11.1%] in QQ192; adjusted hazard ratio, 2.05; 95% confidence interval [CI], 1.32–3.18) and of major adverse cardiac events (88/681 events [13.6%] in RR192 and QR192 and 102/584 events [18.0%] in QQ192; adjusted hazard ratio, 1.48; 95% CI, 1.09–2.03; P=.01). The incidence of major adverse cardiac events was significantly lower in participants in the highest PON1 activity quartile (23/315 [7.3%]) and 235/324 [7.7%] for paraoxonase and arylesterase, respectively) compared with those in the lowest activity quartile (78/311 [25.1%] and 75/319 [23.5%]; P<.001 for paraoxonase and arylesterase, respectively). The adjusted hazard ratios for major adverse cardiac events between the highest and lowest PON1 activity quartiles were, for paraoxonase, 3.4 (95% CI, 2.1–5.5; P<.001) and for arylesterase, 2.9 (95% CI, 1.8–4.7; P<.001) and remained independent in multivariate analysis. Conclusion This study provides direct evidence for a mechanistic link between genetic determinants and activity of PON1 with systemic oxidative stress and prospective cardiovascular risk, indicating a potential mechanism for the atheroprotective function of PON1. PMID:18349088

Bhattacharya, Tamali; Nicholls, Stephen J.; Topol, Eric J.; Zhang, Renliang; Yang, Xia; Schmitt, David; Fu, Xiaoming; Shao, Mingyuan; Brennan, Danielle M.; Ellis, Stephen G.; Brennan, Marie-Luise; Allayee, Hooman; Lusis, Aldons J.; Hazen, Stanley L.

2010-01-01

401

Systemic and Vascular Alterations in Healthy and Cardiovascular Compromised Rats Exposed to Libby Amphibole  

EPA Science Inventory

Rationale: Acute pulmonary injury and chronic disease can impact systemic vasculature because the lung capillary network can release inflammogenic and vasoactive mediators into the circulation. Occupational exposure to Libby amphibole (LA) type asbestos is associated with increas...

402

Cardiovascular Disease in Latin American Patients with Systemic Lupus Erythematosus: A Cross-Sectional Study and a Systematic Review  

PubMed Central

Objective. This study was performed to determine the prevalence of and associated risk factors for cardiovascular disease (CVD) in Latin American (LA) patients with systemic lupus erythematosus (SLE). Methods. First, a cross-sectional analytical study was conducted in 310 Colombian patients with SLE in whom CVD was assessed. Associated factors were examined by multivariate regression analyses. Second, a systematic review of the literature on CVD in SLE in LA was performed. Results. There were 133 (36.5%) Colombian SLE patients with CVD. Dyslipidemia, smoking, coffee consumption, and pleural effusion were positively associated with CVD. An independent effect of coffee consumption and cigarette on CVD was found regardless of gender and duration of disease. In the systematic review, 60 articles fulfilling the eligibility criteria were included. A wide range of CVD prevalence was found (4%–79.5%). Several studies reported ancestry, genetic factors, and polyautoimmunity as novel risk factors for such a condition. Conclusions. A high rate of CVD is observed in LA patients with SLE. Awareness of the observed risk factors should encourage preventive population strategies for CVD in patients with SLE aimed at facilitating the suppression of cigarette smoking and coffee consumption as well as at the tight control of dyslipidemia and other modifiable risk factors. PMID:24294522

Amaya-Amaya, Jenny; Caro-Moreno, Julián; Molano-González, Nicolás; Mantilla, Rubén D.; Rojas-Villarraga, Adriana; Anaya, Juan-Manuel

2013-01-01

403

Dual renin-angiotensin system inhibition for prevention of renal and cardiovascular events: do the latest trials challenge existing evidence?  

PubMed Central

Circulatory and tissue renin-angiotensin systems (RAS) play a central role in cardiovascular (CV) and renal pathophysiology, making RAS inhibition a logical therapeutic approach in the prevention of CV and renal disease in patients with hypertension. The cardio- and renoprotective effects observed with angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) monotherapy, together with the availability of a direct renin inhibitor (DRI), led to the investigation of the potential benefits of dual RAS inhibition. In small studies, ARB and ACE inhibitor combinations were shown to be beneficial in patients with CV or renal disease, with improvement in surrogate markers. However, in larger outcome trials, involving combinations of ACE inhibitors, ARBs or DRIs, dual RAS inhibition did not show reduction in mortality in patients with diabetes, heart failure, coronary heart disease or after myocardial infarction, and was in fact, associated with increased harm. A recent meta-analysis of all major trials conducted over the past 22 years involving dual RAS inhibition has clearly shown that the risk-benefit ratio argues against the use of dual RAS inhibition. Hence, the recent evidence clearly advocates against the use of dual RAS inhibition, and single RAS inhibition appears to be the most suitable approach to controlling blood pressure and improving patient outcomes. PMID:23866091

2013-01-01

404

Determination of the effects of pulmonary arterial hypertension and therapy on the cardiovascular system of rats by impedance cardiography  

PubMed Central

Aim To evaluate the effects of bosentan, sildenafil, and combined therapy on the cardiovascular system using impedance cardiography (ICG) in rats with monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH). Methods Seventy male Wistar-albino rats were randomized into five groups. A single dose of MCT was given to all rats, except to the control group. After 4 weeks, bosentan, sildenafil, and combined treatment was started and lasted for 3 weeks. The last group that developed PAH did not receive any medication. Echocardiographic evaluation was performed to determine the PAH development. Thoracic fluid content index (TFCI), stroke volume index (SI), heart rate (HR), cardiac index (CI), and myocardial contractility index (IC) were determined. All procedures were performed at the baseline and after 4 and 7 weeks. Results Echocardiographic parameters showed that the all MCT-injected rats developed PAH. There were no significant inter- and intra-group differences in TFCI, SI, and IC (P?>?0.05), but at the 7th week, CI value in the sildenafil-treated PAH rats was significantly higher than in other groups and HR of PAH rats with combined therapy was significantly lower than in other groups. Conclusion PAH did not have an effect on LV function of rats, or if it did, the effect was compensated by physiological processes. Also, sildenafil treatment deteriorated the LV cardiac index. PMID:25358882

Buyukakilli, Belgin; Gurgul, Serkan; C?t?r?k, Derya; Hallioglu, Olgu; Ozeren, Murat; Tasdelen, Bahar

2014-01-01

405

The importance of the renin-angiotensin system in normal cardiovascular homeostasis  

NASA Technical Reports Server (NTRS)

Studies were carried out on adult mongrel dogs (20 to 30 kilograms) to investigate the importance of the renin-angiotensin system. Results indicate that the renin-angiotensin system plays a major role in the maintenance of circulatory homeostasis when extracellular fluid volume is depleted. It was also found that angiotensin II concentration, in addition to renal perfusion pressure, is a factor in the regulation of renin release.

Haber, E.

1975-01-01

406

Systems Theory and Modeling  

NSDL National Science Digital Library

From the website: 'This site is for teachers, students, and anyone else who would like a very brief, general introduction to systems thinking and systems modeling. It was written primarily as a teaching resource for college and high school instructors who are short on time, but dedicated to helping students frame and focus their thinking on environmental issues or other complicated, interdisciplinary topics. The site assumes no prior knowledge of systems theory or modeling techniques and covers only the basics, but it includes references to more advanced information for anyone who wants to study this subject in greater depth.'

Division of Science and Environmental Policy at California State University, Monterey Bay

407

Relation of reduction in urinary albumin excretion to ten-year cardiovascular mortality in patients with type 2 diabetes and systemic hypertension.  

PubMed

Microalbuminuria is one of the strongest predictors of both adverse renal and cardiovascular disease (CVD) outcomes in patients with type 2 diabetes mellitus. Although measurement of urinary albumin excretion (UAE) is widely recommended, limited data are available to suggest that reducing UAE translates into a reduction in long-term cardiovascular mortality, particularly among patients without overt nephropathy, who constitute most patients with type 2 diabetes worldwide. We assessed whether changes in the UAE at 1 year were associated with cardiovascular mortality in 393 patients with hypertension and type 2 diabetes during a 10-year period. On univariate analysis, CVD history, age, diabetes duration, and change in UAE at 1 year were associated with cardiovascular mortality risk (hazard ratio 2.60 for those with CVD history, 95% confidence interval [CI] 1.47 to 4.62; hazard ratio 1.59 per 10 years of diabetes duration, 95% CI 1.12 to 2.25; and hazard ratio 1.49 per log UAE increase, 95% CI 1.13 to 1.96). In a stepwise Cox regression model that included baseline UAE and CVD history, the 10-year predicted mortality of those with a decrease in UAE of 2 logs at 1 year was 4.7% (95% CI 1.4% to 7.8%). For those with an increase in UAE of 2 logs at 1 year, it was 24.5% (95% CI 10.1% to 36.5%). In conclusion, these data support current guideline recommendations to screen for UAE in all patients with type 2 diabetes, even in the absence of nephropathy, and suggest that serial UAE measurements even after the initiation of antihypertensive therapy has prognostic value independent of traditional cardiovascular risk factors. PMID:22440125

Estacio, Raymond O; Dale, Rita A; Schrier, Robert; Krantz, Mori J

2012-06-15

408

Model deformation system  

NASA Technical Reports Server (NTRS)

The development of a system to measure model deflections encountered in the National Transonic Facility is discussed. The goal is to be able to measure peak deflections of up to 3 in. with accuracies to within 0.0025 in. over an area 1 m square as the model pitches through an included angle of 30 deg. Stereophotogrammetric techniques are being implemented, with the initial system being an extension of standard techniques. A second system, which will be all electronic, is under development. Both techniques require targets to be strategically placed on the model. Active targets are being developed for location in the model in order to maximize the signal-to-noise ratio and to approximate a point source. Image processing techniques and stereophotogrammetric data reduction programs are being implemented to perform the data reduction tasks.

Holmes, H. K.

1983-01-01

409

Disease severity and therapy as predictors of cardiovascular risk in psoriasis: a population-based cohort study  

PubMed Central

Background Previous studies suggest an increased risk of cardiovascular disease in psoriasis, but the relative contributions of traditional risk factors and markers of disease severity are unclear. We examined the effect of psoriasis disease characteristics on cardiovascular risk after adjusting for traditional cardiovascular risk factors. Methods Study populations included (a) case-cohort sample of 771 patients nested within a population-based psoriasis incidence cohort, and (b) cohort of 1905 patients with incident and prevalent psoriasis patients. Both cohorts were followed up to ascertain disease and treatment characteristics, traditional cardiovascular risk factors and cardiovascular outcomes. Cox proportional hazards regression models were used to identify predictors of cardiovascular outcomes. Results After adjusting for traditional risk factors, increasing number of psoriasis affected body sites at disease onset (HR 1.53 per additional site, 95% CI: 1.20, 1.95) was significantly associated with an increased risk of cardiovascular outcomes. Phototherapy (HR 3.76, 95% CI: 2.45, 5.77) and systemic therapy (HR 2.17, 95% CI: 1.50, 3.13) were associated with a higher risk of cardiovascular outcomes in univariate analyses, but these relatively strong associations disappeared after adjusting for cardiovascular risk factors. Conclusion Increasing number of psoriasis affected body sites may be a severity indicator in psoriasis and is associated with an increased cardiovascular risk. Due to low number of patients exposed to systemic therapy, this study had limited power to examine the effect of treatment on cardiovascular risk. Strong associations with phototherapy and systemic therapy suggest that the cardiovascular risk in psoriasis is confined to patients with severe disease. PMID:22339785

Maradit-Kremers, Hilal; Icen, Murat; Ernste, Floranne C.; Dierkhising, Ross A.; McEvoy, Marian T.

2012-01-01

410

Cardiovascular physiology at high altitude.  

PubMed

The role of the cardiovascular system is to deliver oxygenated blood to the tissues and remove metabolic effluent. It is clear that this complex system will have to adapt to maintain oxygen deliver in the profound hypoxia of high altitude. The literature on the adaptation of both the systemic and pulmonary circulations to high altitude is reviewed. PMID:21465906

Hooper, T; Mellor, A

2011-03-01

411

The role of autacoids and the autonomic nervous system in cardiovascular responses to radio-frequency energy heating.  

PubMed

Among the potential effects of exposure to high levels of radio-frequency energy (RFE) (which includes microwaves), an increase in body temperature is the primary consequence. Release of autacoids and activity of the autonomic nervous system may influence (or be directly responsible for) some of the physiological changes that occur in conjunction with this hyperthermia. The main focus of this review is the interaction of autacoids and the autonomic nervous system with cardiovascular changes during heating. Differences between environmental and RFE-induced heating (such as rate of temperature change and degree of skin vs. core heating) may be important when considering these effects. Antihistamines exhibited no beneficial effect on circulatory collapse during RFE-induced heating. The serotonergic blocker methysergide decreased survival time in rats during terminal RFE exposure, despite no effects on heart rate (HR) or blood pressure. Although blockade of platelet-activating factor resulted in lower HR before RFE exposure, there was a lack of effect on the subsequent increase in HR during heating. Nitric oxide did not contribute to the hypotension that occurs due to rapid heating by RFE exposure. There have been either no or very limited studies of effects of prostaglandins, bradykinin, or angiotensin on RFE-induced heating responses. beta-Adrenoceptor antagonism with propranolol resulted in significantly decreased survival times and lower final colonic temperatures during RFE exposure. A lack of effects of nadolol on survival time and temperature, coupled with its poor ability to traverse the blood-brain barrier, suggests that central beta-adrenergic stimulation rather than peripheral stimulation may alter thermoregulation. Effects of the autonomic nervous system (as studied by adrenoceptor blockade) on potassium changes during heating have not been fully investigated. Such changes could be important in animals' responses to RFE and other modalities of heating, and should be studied in future. PMID:16553641

Jauchem, J R

2006-04-01

412

The chick embryo as an expanding experimental model for cancer and cardiovascular research  

PubMed Central

A long and productive history in biomedical research defines the chick as a model for human biology. Fundamental discoveries, including the description of directional circulation propelled by the heart and the link between oncogenes and the formation of cancer, indicate its utility in cardiac biology and cancer. Despite the more recent arrival of several vertebrate and invertebrate animal models during the last century, the chick embryo remains a commonly used model for vertebrate biology and provides a tractable biological template. With new molecular and genetic tools applied to the avian genome the chick embryo is accelerating the discovery of normal development and elusive disease processes. Moreover, progress in imaging and chick culture technologies is advancing real-time visualization of dynamic biological events, such as tissue morphogenesis, angiogenesis and cancer metastasis. A rich background of information, coupled with new technologies and relative ease of maintenance suggest an expanding utility for the chick embryo in cardiac biology and cancer research. PMID:24357262

Kain, Kristin H.; Miller, James W.I.; Jones-Paris, Celestial R.; Thomason, Rebecca T.; Lewis, John D.; Bader, David M.; Barnett, Joey V.; Zijlstra, Andries

2014-01-01

413

Trends in Major Risk Factors for Cardiovascular Disease Among Adults in the Mississippi Delta Region, Mississippi Behavioral Risk Factor Surveillance System, 2001–2010  

PubMed Central

Introduction The prevalences of major modifiable risk factors for cardiovascular disease (CVD) are disproportionately high in the 18-county Mississippi Delta region, and many of these risk factors disproportionately affect blacks. Temporal trends in the prevalence of CVD risk factors in the Mississippi Delta have not been determined. We examined trends in CVD risk factors from 2001 to 2010 in the region. Methods Longitudinal trends in prevalence of high blood pressure, high cholesterol, diabetes, obesity, physical inactivity, and current smoking were investigated using self-reported data from the Behavioral Risk Factor Surveillance System. Joinpoint regression models were used to examine annual percentage change (APC) in the prevalence of these risk factors. Results Overall, from 2001 to 2010, we observed significant increases in the prevalence of high cholesterol (APC, 4.22%), obesity (APC, 3.65%), and diabetes (APC, 3.54%). Among blacks, we found significant increases in the prevalence of high cholesterol (APC, 3.41%), obesity (APC, 3.48%), and diabetes (APC, 4.96%). Among whites, we found significant increases in high blood pressure (APC, 2.18%), high cholesterol (APC, 4.78%), obesity (APC, 4.18%), and physical inactivity (APC, 3.06%). We also observed a significant decrease in smoking among whites (APC, ?1.99%). Conclusion From 2001 to 2010, we found a significant increase in the prevalence of high cholesterol, diabetes, and obesity in the Mississippi Delta. We also observed racial differences in those prevalences. PMID:25695259

Vargas, Rodolfo

2015-01-01

414

Efficient anisotropic adaptive discretization of the cardiovascular system O. Sahni a,*, J. Muller a  

E-print Network

to maintain structured and graded elements near the wall resulting in a more accurate wall shear stress- ing vessel model. The efficiency of our approach is measured by analyzing the wall shear stress blood flow; Wall shear stress 1. Introduction In recent years, the relationship between hemodynamic

Frey, Pascal

415

ESMDIS: Earth System Model Data Information System  

Microsoft Academic Search

The goal of the development of the Earth System Model Data Information System (ESMDIS) are to provide Earth scientists with: 1) an output management system of Earth System Model (ESM) to browse the metadata and retrieve a desired subset of ESM output; 2) an analysis system of ESM output and other related datasets; 3) an automated pipelining system for ESM

Yuechen Chi; Carlos R. Mechoso; Michael Stonebraker; Keith Sklower; Richard Troy; Richard R. Muntz; Edmond Mesrobian

1997-01-01

416

Investigating Autonomic Control of the Cardiovascular System: A Battery of Simple Tests  

ERIC Educational Resources Information Center

Sympathetic and parasympathetic divisions of the autonomic nervous system constantly control the heart (sympathetic and parasympathetic divisions) and blood vessels (predominantly the sympathetic division) to maintain appropriate blood pressure and organ blood flow over sometimes widely varying conditions. This can be adversely affected by…

Johnson, Christopher D.; Roe, Sean; Tansey, Etain A.

2013-01-01

417

Semiparametric risk prediction models for recurrent cardiovascular events in the LIPID study  

Microsoft Academic Search

BACKGROUND: Traditional methods for analyzing clinical and epidemiological cohort study data have been focused on the first occurrence of a health outcome. However, in many situations, recurrent event data are frequently observed. It is inefficient to use methods for the analysis of first events to analyse recurrent event data. METHODS: We applied several semi-parametric proportional hazards models to analyze the

Jisheng Cui; Andrew Forbes; Adrienne Kirby; Ian Marschner; John Simes; David Hunt; Malcolm West; Andrew Tonkin

2010-01-01

418

Development of a cardiopulmonary mathematical model incorporating a baro-chemoreceptor reflex control system.  

PubMed

This article describes the development of a comprehensive mathematical model of the human cardiopulmonary system that combines the respiratory and cardiovascular systems and their associated autonomous nervous control actions. The model is structured to allow the complex interactions between the two systems and the responses of the combined system to be predicted under different physiological conditions. The cardiovascular system model contains 13 compartments, including the heart chambers operating as a pump and the blood vessels represented as distensible tubes configured in a serial and parallel arrangement. The accurate representation of the hemodynamics in the system and the good fit to published pressure and flow waveforms gave confidence in the modelling approach adopted for the cardiovascular system prior to the incorporation of the baroreflex control and the respiratory models. An improved baroreceptor reflex model is developed in this research, incorporating afferent, central and efferent compartments. A sigmoid function is included in the efferent compartment to produce sympathetic and parasympathetic nerve outflow to the effector sites. The baroreflex action is modelled using physiological data, its interaction with the chemoreflex control is explained and the simulation results presented show the ability of the model to predict the static and dynamic hemodynamic responses to environmental disturbances. A previously published respiratory model that includes the mechanics of breathing, gas exchange process and the regulation of the system is then combined with the cardiovascular model to form the cardiopulmonary model. Through comparison with published data, the cardiopulmonary model with the baro-chemoreflex control is validated during hypoxia and hypercapnia. The percentage difference between the predicted and measured changes in the heart rates and the mean arterial pressures are within 3% in both cases. The total peripheral resistance correlates well for hypoxia but is less good for hypercapnia, where the predicted change from normal condition is around 7% compared with a measured change of 23%. An example showing the application of the proposed model in sport science is also included. PMID:23157080