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1

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

2

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

3

Mathematical modeling and analysis of a cardiovascular system  

NASA Astrophysics Data System (ADS)

In this paper, we will analyze a mathematical model associated to a cardiovascular process. This process is described in [1]. Mathematical modeling of this process leads to a system of differential equations with delay. We prove the existence of equilibrium point for this system and we show that the equilibrium point exhibits the Hopf bifurcation.

Pogorevici, A.; Juratoni, A.; Bund?u, O.

2012-09-01

4

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

5

A forward model-based validation of cardiovascular system identification  

NASA Technical Reports Server (NTRS)

We present a theoretical evaluation of a cardiovascular system identification method that we previously developed for the analysis of beat-to-beat fluctuations in noninvasively measured heart rate, arterial blood pressure, and instantaneous lung volume. The method provides a dynamical characterization of the important autonomic and mechanical mechanisms responsible for coupling the fluctuations (inverse modeling). To carry out the evaluation, we developed a computational model of the cardiovascular system capable of generating realistic beat-to-beat variability (forward modeling). We applied the method to data generated from the forward model and compared the resulting estimated dynamics with the actual dynamics of the forward model, which were either precisely known or easily determined. We found that the estimated dynamics corresponded to the actual dynamics and that this correspondence was robust to forward model uncertainty. We also demonstrated the sensitivity of the method in detecting small changes in parameters characterizing autonomic function in the forward model. These results provide confidence in the performance of the cardiovascular system identification method when applied to experimental data.

Mukkamala, R.; Cohen, R. J.

2001-01-01

6

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

7

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

8

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

9

Cardiovascular system  

MedlinePLUS Videos and Cool Tools

... from the tissues to the systems of the body through which they are eliminated. Most of the blood is made up of a watery, protein-laden fluid called plasma. A little less than half of this blood volume is composed of red and white blood cells, and other solid elements called platelets.

10

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

11

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

12

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

13

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

14

Object-oriented modeling and simulation of the closed loop cardiovascular system by using SIMSCAPE.  

PubMed

The modeling of physiological systems via mathematical equations reflects the calculation procedure more than the structure of the real system modeled, with the simulation environment SIMULINK™ being one of the best suited to this strategy. Nevertheless, object-oriented modeling is spreading in current simulation environments through the use of the individual components of the model and its interconnections to define the underlying dynamic equations. In this paper we describe the use of the SIMSCAPE™ simulation environment in the object-oriented modeling of the closed loop cardiovascular system. The described approach represents a valuable tool in the teaching of physiology for graduate medical students. PMID:23428370

de Canete, J Fernandez; del Saz-Orozco, P; Moreno-Boza, D; Duran-Venegas, E

2013-05-01

15

A dimensionally-heterogeneous closed-loop model for the cardiovascular system and its applications.  

PubMed

In the present work a computational model of the entire cardiovascular system is developed using heterogeneous mathematical representations. This model integrates different levels of detail for the blood circulation. The arterial tree is described by a one dimensional model in order to simulate the wave propagation phenomena that take place at the larger arterial vessels. The inflow and outflow locations of this 1D model are coupled with lumped parameter descriptions of the remainder part of the circulatory system, closing the loop. The four cardiac valves are considered using a valve model which allows for stenoses and regurgitation phenomena. In addition, full 3D geometrical models of arterial districts are embedded in this closed-loop circuit to model the local blood flow in specific vessels. This kind of detailed closed-loop network for the cardiovascular system allows hemodynamics analyses of patient-specific arterial district, delivering naturally the appropriate boundary conditions for different cardiovascular scenarios. An example of application involving the effect of aortic insufficiency on the local hemodynamics of a cerebral aneurism is provided as a motivation to reproduce, through numerical simulation, the hemodynamic environment in patients suffering from infective endocarditis and mycotic aneurisms. The need for incorporating homeostatic control mechanisms is also discussed in view of the large sensitivity observed in the results, noting that this kind of integrative modeling allows such incorporation. PMID:22902782

Blanco, P J; Feijóo, R A

2013-05-01

16

Computational flow dynamics in patient specific model of cardiovascular system using CT and MRI  

NASA Astrophysics Data System (ADS)

After introduction on a new multislice computed tomography (MSCT) scanner, it has become possible to produce highspeed CT angiography (CTA) that selected preferred method for imaging in emergent vascular conditions. On the other hand, the imaging of blood vessels is often referred to as magnetic resonance angiography (MRA). Both of angiography offers the good quality of three-dimensional information of the vessels. In this study, patient specific model were reconstructed using multi-slice computed tomography (CT) and magnetic resonance imaging (MRI). The optimal transit time from intravenous injection to enhancement cardiovascular system was determined using a contrast bolus tracking technique with CT examination and phase contrast magnetic resonance angiography (PC-MRA). The purpose of this study was to describe a novel blood flow visualization and analysis in the human cardiovascular system in more detail by constructing actual three-dimensional (3D) flow and simulated model using Computational flow dynamics (CFD) methods. CFD streamlines were displayed using a special illumination technique with blood pressure display, which gives a much better spatial understanding of the field's structure than ordinary constant-colored lines. Real vector display using PC-MRA was also expressed to compare with the CFD simulation. On conclusion, Patient specific approach using actual blood flow with PC-MRA and CFD were effective to estimate blood flow state of the cardiovascular system.

Yamamoto, S.; Bartsch, H.; Maruyama, S.; Yoneyama, S.; Wada, S.; Yamaguchi, T.; Naito, H.

2006-03-01

17

[A hardware-in-the-loop simulation model of the cardiovascular system for ventricular assist device evaluation].  

PubMed

This paper presents a novel technique for evaluating the performance of ventricular assist devices in vitro, innovatively combining dynamic physical testing of assist devices with a mature, numerical human cardiovascular model. Based on this technique, one self-made direct mechanical ventricular assistance (DMVA) prototype is tested. With the true representation of device performance in vivo, the real-time interactions between DMVA and the cardiovascular system are captured and studied. Hemodynamic simulations under DMVA are performed. Experimental results demonstrate that it provides a useful tool for the study of device assist impact on the cardiovascular system as well as the improvement of device structure and effectiveness of control mechanism. PMID:20391921

Honglei, Li; Ming, Yang; Shiyang, Li

2010-01-01

18

Ghrelin and the cardiovascular system.  

PubMed

Ghrelin is a peptide that was originally isolated from the stomach. It exerts potent growth hormone (GH)-releasing and orexigenic activities. Several studies have highlighted the therapeutic benefits of ghrelin for the treatment of cardiovascular disease. In animal models of chronic heart failure, the administration of ghrelin improved cardiac function and remodeling; these findings were replicated in human patients with heart failure. Moreover, in an animal study, ghrelin administration effectively reduced pulmonary hypertension induced by chronic hypoxia. In addition, repeated administration of ghrelin to cachectic patients with chronic obstructive pulmonary disease had positive effects on overall body function, including muscle wasting, functional capacity and sympathetic activity. The administration of ghrelin early after myocardial infarction (MI) reduced fatal arrhythmia and related mortality. In ghrelin-deficient mice, both exogenous and endogenous ghrelin were protective against fatal arrhythmia and promoted remodeling after MI. Although the mechanisms underlying the effects of ghrelin on the cardiovascular system remain unclear, there are indications that its beneficial effects are mediated through both direct physiological actions, including increased GH levels, improved energy balance and direct actions on cardiovascular cells, and regulation of autonomic nervous system activity. Therefore, ghrelin is a promising novel therapeutic agent for cardiovascular disease. © 2014 S. Karger AG, Basel. PMID:24943303

Tokudome, Takeshi; Kishimoto, Ichiro; Miyazato, Mikiya; Kangawa, Kenj

2014-01-01

19

[Thyroid and cardiovascular system].  

PubMed

The cardiocirculatory changes in hyperthyroidism seem to be an accommodation to the increased metabolic demands and lead to an increased perfusion of the peripheral tissues. Due to the influence of elevated thyroid hormone levels, contractility, stroke volume, resting heart rate, and contraction and relaxation velocity of the left ventricle increase. Caused by direct effect on the smooth vascular muscle, systemic vascular resistance is decreased with the consequence of a diminished afterload and an increased cardiac efficiency. The activation of the renin-angiotensin-aldosteron system and the increased production of erythropoietin additionally lead to an increased blood volume, which increases cardiac preload together with the increased venous backflow. Manifest hypothyroidism is characterized by bradycardia and diastolic dysfunction in rest and systolic dysfunction at stress. Despite a slight increase of diastolic blood pressure due to an increased systemic vascular resistance, blood pressure remains nearly stable because of diminished cardiac output. Hypercholesterinaemia and diastolic hypertension in hypothyroid patients can lead to the development of arteriosclerosis and coronary heart disease (CHD). Also subclinical hypothyroidism is associated with a significantly higher risk for arteriosclerosis and CHD, whereas subclinical hyperthyroidism seems to be associated with an increased mortality for all reasons, especially for cardiovascular diseases. PMID:16424999

Gallowitsch, Hans-Jürgen

2005-10-01

20

Validation of subject-specific cardiovascular system models from porcine measurements.  

PubMed

A previously validated mathematical model of the cardiovascular system (CVS) is made subject-specific using an iterative, proportional gain-based identification method. Prior works utilised a complete set of experimentally measured data that is not clinically typical or applicable. In this paper, parameters are identified using proportional gain-based control and a minimal, clinically available set of measurements. The new method makes use of several intermediary steps through identification of smaller compartmental models of CVS to reduce the number of parameters identified simultaneously and increase the convergence stability of the method. This new, clinically relevant, minimal measurement approach is validated using a porcine model of acute pulmonary embolism (APE). Trials were performed on five pigs, each inserted with three autologous blood clots of decreasing size over a period of four to five hours. All experiments were reviewed and approved by the Ethics Committee of the Medical Faculty at the University of Liege, Belgium. Continuous aortic and pulmonary artery pressures (P(ao), P(pa)) were measured along with left and right ventricle pressure and volume waveforms. Subject-specific CVS models were identified from global end diastolic volume (GEDV), stroke volume (SV), P(ao), and P(pa) measurements, with the mean volumes and maximum pressures of the left and right ventricles used to verify the accuracy of the fitted models. The inputs (GEDV, SV, P(ao), P(pa)) used in the identification process were matched by the CVS model to errors <0.5%. Prediction of the mean ventricular volumes and maximum ventricular pressures not used to fit the model compared experimental measurements to median absolute errors of 4.3% and 4.4%, which are equivalent to the measurement errors of currently used monitoring devices in the ICU (?5-10%). These results validate the potential for implementing this approach in the intensive care unit. PMID:22126892

Revie, James A; Stevenson, David J; Chase, J Geoffrey; Hann, Christopher E; Lambermont, Bernard C; Ghuysen, Alexandre; Kolh, Philippe; Shaw, Geoffrey M; Heldmann, Stefan; Desaive, Thomas

2013-02-01

21

Long-term regulation in the cardiovascular system - Cornerstone in the development of a composite physiological model  

NASA Technical Reports Server (NTRS)

The present work discusses a model of the cardiovascular system and related subsystems capable of long-term simulations of the type desired for in-space hypogravic human physiological performance prediction. The discussion centers around the model of Guyton and modifications of it. In order to draw attention to the fluid handling capabilities of the model, one of several transfusion simulations performed is presented, namely, the isotonic saline transfusion simulation.

White, R. J.

1974-01-01

22

Modelling of cardiovascular system: development of a hybrid (numerical-physical) model.  

PubMed

Physical models of the circulation are used for research, training and for testing of implantable active and passive circulatory prosthetic and assistance devices. However, in comparison with numerical models, they are rigid and expensive. To overcome these limitations, we have developed a model of the circulation based on the merging of a lumped parameter physical model into a numerical one (producing therefore a hybrid). The physical model is limited to the barest essentials and, in this application, developed to test the principle, it is a windkessel representing the systemic arterial tree. The lumped parameters numerical model was developed in LabVIEW environment and represents pulmonary and systemic circulation (except the systemic arterial tree). Based on the equivalence between hydraulic and electrical circuits, this prototype was developed connecting the numerical model to an electrical circuit--the physical model. This specific solution is valid mainly educationally but permits the development of software and the verification of preliminary results without using cumbersome hydraulic circuits. The interfaces between numerical and electrical circuits are set up by a voltage controlled current generator and a voltage controlled voltage generator. The behavior of the model is analyzed based on the ventricular pressure-volume loops and on the time course of arterial and ventricular pressures and flow in different circulatory conditions. The model can represent hemodynamic relationships in different ventricular and circulatory conditions. PMID:14738194

Ferrari, G; Kozarski, M; De Lazzari, C; Górczy?ska, K; Mimmo, R; Guaragno, M; Tosti, G; Darowski, M

2003-12-01

23

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.

2011-01-01

24

Towards patient-specific cardiovascular modeling system using the immersed boundary technique  

PubMed Central

Background Previous research shows that the flow dynamics in the left ventricle (LV) reveal important information about cardiac health. This information can be used in early diagnosis of patients with potential heart problems. The current study introduces a patient-specific cardiovascular-modelling system (CMS) which simulates the flow dynamics in the LV to facilitate physicians in early diagnosis of patients before heart failure. Methods The proposed system will identify possible disease conditions and facilitates early diagnosis through hybrid computational fluid dynamics (CFD) simulation and time-resolved magnetic resonance imaging (4-D MRI). The simulation is based on the 3-D heart model, which can simultaneously compute fluid and elastic boundary motions using the immersed boundary method. At this preliminary stage, the 4-D MRI is used to provide an appropriate comparison. This allows flexible investigation of the flow features in the ventricles and their responses. Results The results simulate various flow rates and kinetic energy in the diastole and systole phases, demonstrating the feasibility of capturing some of the important characteristics of the heart during different phases. However, some discrepancies exist in the pulmonary vein and aorta flow rate between the numerical and experimental data. Further studies are essential to investigate and solve the remaining problems before using the data in clinical diagnostics. Conclusions The results show that by using a simple reservoir pressure boundary condition (RPBC), we are able to capture some essential variations found in the clinical data. Our approach establishes a first-step framework of a practical patient-specific CMS, which comprises a 3-D CFD model (without involving actual hemodynamic data yet) to simulate the heart and the 4-D PC-MRI system. At this stage, the 4-D PC-MRI system is used for verification purpose rather than input. This brings us closer to our goal of developing a practical patient-specific CMS, which will be pursued next. We anticipate that in the future, this hybrid system can potentially identify possible disease conditions in LV through comprehensive analysis and facilitates physicians in early diagnosis of probable cardiac problems.

2011-01-01

25

A new integrated method for analyzing heart mechanics using a cell-hemodynamics-autonomic nerve control coupled model of the cardiovascular system.  

PubMed

A model of the cardiovascular system coupling cell, hemodynamics, and autonomic nerve control function is proposed for analyzing heart mechanics. We developed a comprehensive cardiovascular model with multi-physics and multi-scale characteristics that simulates the physiological events from membrane excitation of a cardiac cell to contraction of the human heart and systemic blood circulation and ultimately to autonomic nerve control. A lumped parameter model is used to compute the systemic and pulmonary circulations interacting with the cardiac cell mechanism. For autonomic control of the cardiovascular system, we used the approach suggested by Heldt et al. [2002. Computational modeling of cardiovascular response to orthostatic stress. J. Appl. Physiol. 92, 1239-1254] (Heldt model), including baroreflex and cardiopulmonary reflexes. We assumed sympathetic and parasympathetic pathways for the nerve control system. The cardiac muscle response to these reflex control systems was implemented using the activation-level changes in the L-type calcium channel and sarcoplasmic/endoplasmic reticulum calcium ATPase function based on experimental observations. Using this model, we delineated the cellular mechanism of heart contractility mediated by nerve control function. To verify the integrated method, we simulated a 10% hemorrhage, which involves cardiac cell mechanics, circulatory hemodynamics, and nerve control function. The computed and experimental results were compared. Using this methodology, the state of cardiac contractility, influenced by diverse properties such as the afterload and nerve control systems, is easily assessed in an integrated manner. PMID:17904205

Shim, Eun Bo; Jun, Hyung Min; Leem, Chae Hun; Matusuoka, Satoshi; Noma, Akinori

2008-01-01

26

Mathematical Model of Cardiovascular Response to Dynamic Exercise.  

National Technical Information Service (NTIS)

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 cont...

E. Magosso A. Felicani M. Ursino

2001-01-01

27

Cardiovascular involvement in systemic autoimmune diseases  

Microsoft Academic Search

Autoimmune diseases, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), primary antiphospholipid syndrome (APS), systemic sclerosis and systemic vasculitis, affect a large number of people in whom one of the leading causes of morbidity and mortality is cardiovascular disease. Cardiovascular disease is associated with the development of accelerated atherosclerosis. It seems to occur at a younger age than in the

Simona Sitia; Fabiola Atzeni; Piercarlo Sarzi-Puttini; Vitantonio Di Bello; Livio Tomasoni; Luigi Delfino; Francesco Antonini-Canterin; Giovanni Di Salvo; Vito De Gennaro Colonna; Salvatore La Carrubba; Scipione Carerj; Maurizio Turiel

2009-01-01

28

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.

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

2012-01-01

29

Cardiovascular Magnetic Resonance Imaging in Experimental Models  

PubMed Central

Cardiovascular magnetic resonance (CMR) imaging is the modality of choice for clinical studies of the heart and vasculature, offering detailed images of both structure and function with high temporal resolution. Small animals are increasingly used for genetic and translational research, in conjunction with models of common pathologies such as myocardial infarction. In all cases, effective methods for characterising a wide range of functional and anatomical parameters are crucial for robust studies. CMR is the gold-standard for the non-invasive examination of these models, although physiological differences, such as rapid heart rate, make this a greater challenge than conventional clinical imaging. However, with the help of specialised magnetic resonance (MR) systems, novel gating strategies and optimised pulse sequences, high-quality images can be obtained in these animals despite their small size. In this review, we provide an overview of the principal CMR techniques for small animals for example cine, angiography and perfusion imaging, which can provide measures such as ejection fraction, vessel anatomy and local blood flow, respectively. In combination with MR contrast agents, regional dysfunction in the heart can also be identified and assessed. We also discuss optimal methods for analysing CMR data, particularly the use of semi-automated tools for parameter measurement to reduce analysis time. Finally, we describe current and emerging methods for imaging the developing heart, aiding characterisation of congenital cardiovascular defects. Advanced small animal CMR now offers an unparalleled range of cardiovascular assessments. Employing these methods should allow new insights into the structural, functional and molecular basis of the cardiovascular system.

Price, Anthony N.; Cheung, King K.; Cleary, Jon O; Campbell, Adrienne E; Riegler, Johannes; Lythgoe, Mark F

2010-01-01

30

Melatonin and the cardiovascular system.  

PubMed

Melatonin concentrations in serum, as well as urinary levels of its main metabolite, 6-sulphatoxymelatonin, decrease with age. In the course of aging, the frequency of heart diseases, both acute and chronic, systematically increases. The evidence from the last 10 years suggests that melatonin influences the cardiovascular system. The presence of vascular melatoninergic receptors/binding sites has been demonstrated; these receptors are functionally linked with vasoconstrictor or vasodilatory effects of melatonin. Melatonin can contribute in cardioprotection of the rat heart, following myocardial ischemia. It has been shown that patients with coronary heart disease have a low melatonin production rate, especially those with higher risk of cardiac infarction and/or sudden death. There are clinical data reporting some alterations of melatonin in human stroke and coronary heart disease. The suprachiasmatic nucleus and, possibly, the melatoninergic system may also modulate cardiovascular rhythmicity. Hypercholesterolemia and hypertension are the other age-related symptoms. People with high levels of LDL-cholesterol have low levels of melatonin. It has been shown that melatonin suppresses the formation of cholesterol by 38% and reduces LDL accumulation by 42%. A 10-20% reduction of cholesterol concentration in women using the B-oval pill has been observed. It is a very important because, even a 10-15% reduction in blood cholesterol concentration has bee shown to result in a 20 to 30% decrease in the risk of coronary heart disease. People with hypertension have lower melatonin levels than those with normal blood pressure. The administration of the hormone in question declines blood pressure to normal range. It has been observed that melatonin, even in a dose 1 mg, reduced blood pressure and decreased catecholamine level after 90 min in human subjects. Melatonin may reduce blood pressure via the following mechanisms: 1) by a direct effect on the hypothalamus; 2) as an antioxidant which lowers blood pressure; 3) by decreasing the level of catecholamines, or 4) by relaxing the smooth muscle in the aorta wall. PMID:12019357

Sewerynek, Ewa

2002-04-01

31

Development of physiological simulation environment for hemodynamics of cardiovascular system  

Microsoft Academic Search

The purpose of this study is to provide a physiological simulation environment for modeling and diagnosing the cardiovascular system as part of circulatory system in the whole body. The circulatory system model aims to represent various changes and diseases quantitatively based on clinical measurements. In respect with some measurement or diagnosis levels, the circulatory system could be modeled into a

K. Asami; T. Kitamura

2003-01-01

32

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.

Akki, Ashwin; Gupta, Ashish

2013-01-01

33

Alcohol and the Cardiovascular System.  

National Technical Information Service (NTIS)

Numerous studies have concluded that moderate drinking is associated with improved cardiovascular health. As a result, there is considerable government, industry, and public debate as to whether this knowledge should serve as the basis for health recommen...

M. Wassef S. Zakhari

1996-01-01

34

Cardiovascular magnetic resonance in systemic hypertension  

PubMed Central

Systemic hypertension is a highly prevalent potentially modifiable cardiovascular risk factor. Imaging plays an important role in the diagnosis of underlying causes for hypertension, in assessing cardiovascular complications of hypertension, and in understanding the pathophysiology of the disease process. Cardiovascular magnetic resonance (CMR) provides accurate and reproducible measures of ventricular volumes, mass, function and haemodynamics as well as uniquely allowing tissue characterization of diffuse and focal fibrosis. In addition, CMR is well suited for exclusion of common secondary causes for hypertension. We review the current and emerging clinical and research applications of CMR in hypertension.

2012-01-01

35

Thyroid disease and the cardiovascular system.  

PubMed

Thyroid hormones, specifically triiodothyronine (T3), have significant effects on the heart and cardiovascular system. Hypothyroidism, hyperthyroidism, subclinical thyroid disease, and low T3 syndrome each cause cardiac and cardiovascular abnormalities through both genomic and nongenomic effects on cardiac myocytes and vascular smooth muscle cells. In compromised health, such as occurs in heart disease, alterations in thyroid hormone metabolism may further impair cardiac and cardiovascular function. Diagnosis and treatment of cardiac disease may benefit from including analysis of thyroid hormone status, including serum total T3 levels. PMID:24891175

Danzi, Sara; Klein, Irwin

2014-06-01

36

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.

Safak, Koray K.

2013-01-01

37

Modeling of Cardiovascular Response to Weightlessness  

NASA Technical Reports Server (NTRS)

It was the hypothesis of this Project that the Simple lack of hydrostatic pressure in microgravity generates several purely physical reactions that underlie and may explain, in part, the cardiovascular response to weightlessness. For instance, hydrostatic pressure within the ventricles of the heart may improve cardiac performance by promoting expansion of ventricular volume during diastole. The lack of hydrostatic pressure in microgravity might, therefore, reduce diastolic filling and cardiac performance. The change in transmural pressure is possible due to the difference in hydrostatic pressure gradients between the blood inside the ventricle and the lung tissue surrounding the ventricle due to their different densities. On the other hand, hydrostatic pressure within the vasculature may reduce cardiac inlet pressures because of the typical location of the heart above the hydrostatic indifference level (the level at which pressure remains constant throughout changes in gravity). Additional physical responses of the body to changing gravitational conditions may influence cardiovascular performance. For instance, fluid shifts from the lower body to the thorax in microgravity may serve to increase central venous pressure (CVP) and boost cardiac output (CO). The concurrent release of gravitational force on the rib cage may tend to increase chest girth and decrease pedcardial pressure, augmenting ventricular filling. The lack of gravity on pulmonary tissue may allow an upward shifting of lung mass, causing a further decrease in pericardial pressure and increased CO. Additional effects include diuresis early in the flight, interstitial fluid shifts, gradual spinal extension and movement of abdominal mass, and redistribution of circulatory impedance because of venous distention in the upper body and the collapse of veins in the lower body. In this project, the cardiovascular responses to changes in intraventricular hydrostatic pressure, in intravascular hydrostatic pressure and, to a limited extent, in extravascular and pedcardial hydrostatic pressure were investigated. A complete hydraulic model of the cardiovascular system was built and flown aboard the NASA KC-135 and a computer model was developed and tested in simulated microgravity. Results obtained with these models have confirmed that a simple lack of hydrostatic pressure within an artificial ventricle causes a decrease in stroke volume. When combined with the acute increase in ventricular pressure associated with the elimination of hydrostatic pressure within the vasculature and the resultant cephalad fluid shift with the models in the upright position, however, stroke volume increased in the models. Imposition of a decreased pedcardial pressure in the computer model and in a simplified hydraulic model increased stroke volume. Physiologic regional fluid shifting was also demonstrated by the models. The unifying parameter characterizing of cardiac response was diastolic ventricular transmural pressure (DVDELTAP) The elimination of intraventricular hydrostatic pressure in O-G decreased DVDELTAP stroke volume, while the elimination of intravascular hydrostatic pressure increased DVDELTAP and stroke volume in the upright posture, but reduced DVDELTAP and stroke volume in the launch posture. The release of gravity on the chest wall and its associated influence on intrathoracic pressure, simulated by a drop in extraventricular pressure4, increased DVDELTAP ans stroke volume.

Sharp, M. Keith

1999-01-01

38

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.

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

2013-01-01

39

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

The purpose of this investigation is to use a computational model to compare a synchronized valveless pulsatile left ventricular assist device with 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 the 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 with 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 with 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

2013-01-01

40

Multifractal heart rate dynamics in human cardiovascular model  

NASA Astrophysics Data System (ADS)

Human cardiovascular and/or cardio-respiratory systems are shown to exhibit both multifractal and synchronous dynamics, and we recently developed a nonlinear, physiologically plausible model for the synchronization between heartbeat and respiration (Kotani, et al. Phys. Rev. E 65: 051923, 2002). By using the same model, we now show the multifractality in the heart rate dynamics. We find that beat-to-beat monofractal noise (fractional Brownian motion) added to the brain stem cardiovascular areas results in significantly broader singularity spectra for heart rate through interactions between sympathetic and parasympathetic nervous systems. We conclude that the model proposed here would be useful in studying the complex cardiovascular and/or cardio- respiratory dynamics in humans.

Kotani, Kiyoshi; Takamasu, Kiyoshi; Safonov, Leonid; Yamamoto, Yoshiharu

2003-05-01

41

Investigation of Plaque Effects on Cardiovascular Stent System  

Microsoft Academic Search

A 3D composite stent model, which consists of the stent, plaque, and artery wall, is generated to characterize stent transient expansion and deflection behavior using Finite Element Method (FEM) approach. Two types (flat and central-thicker) of plaque models have been employed to evaluate the geometrical effects of atherosclerotic artery on the cardiovascular stent deployment system. Simulation results demonstrated that the

Heng-Chuan Kan

2010-01-01

42

User's instructions for the cardiovascular Walters model  

NASA Technical Reports Server (NTRS)

The model is a combined, steady-state cardiovascular and thermal model. It was originally developed for interactive use, but was converted to batch mode simulation for the Sigma 3 computer. The model has the purpose to compute steady-state circulatory and thermal variables in response to exercise work loads and environmental factors. During a computer simulation run, several selected variables are printed at each time step. End conditions are also printed at the completion of the run.

Croston, R. C.

1973-01-01

43

Physiological homology between Drosophila melanogaster and vertebrate cardiovascular systems  

PubMed Central

SUMMARY 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 whether subtle physiological defects observed in the human cardiovascular system can be reproduced in D. melanogaster. Here we characterize the cardiovascular physiology of D. melanogaster in its pre-pupal stage by using high-speed dye angiography and optical coherence tomography. The heart has vigorous pulsatile contractions that drive intracardiac, aortic and extracellular-extravascular hemolymph flow. Several physiological measures, including weight-adjusted cardiac output, body-length-adjusted aortic velocities and intracardiac shear forces, are similar to those in the closed vertebrate cardiovascular systems, including that of humans. Extracellular-extravascular flow in the pre-pupal D. melanogaster circulation drives convection-limited fluid transport. To demonstrate homology in heart dysfunction, we showed that, at the pre-pupal stage, a troponin I mutant, held-up2 (hdp2), has impaired systolic and diastolic heart wall velocities. Impaired heart wall velocities occur in the context of a non-dilated phenotype with a mildly depressed fractional shortening. We additionally derive receiver operating characteristic curves showing that heart wall velocity is a potentially powerful discriminator of systolic heart dysfunction. Our results demonstrate physiological homology and support the use of D. melanogaster as an animal model of complex cardiovascular disease.

Choma, Michael A.; Suter, Melissa J.; Vakoc, Benjamin J.; Bouma, Brett E.; Tearney, Guillermo J.

2011-01-01

44

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

45

Principal component analysis of HPLC retention data and molecular modeling structural parameters of cardiovascular system drugs in view of their pharmacological activity.  

PubMed

Evaluation of relationships between molecular modeling structural parameters and high-performance liquid chromatography (HPLC) retention data of 11 cardiovascular system drugs by principal component analysis (PCA) in relation to their pharmacological activity was performed. The six retention data parameters were determined on three different HPLC columns (Nucleosil C18 AB with octadecylsilica stationary phase, IAM PC C10/C3 with chemically bounded phosphatidylcholine, and Nucleosil 100-5 OH with chemically bounded propanodiole), and using isocratically acetonitrile: Britton-Robinson buffer as the mobile phase. Additionally, molecular modeling studies were performed with the use of HyperChem software and MM+ molecular mechanics with the semi-empirical AM1 method deriving 20 structural descriptors. Factor analysis obtained with the use of various sets of parameters: structural parameters, HPLC retention data, and all 26 considered parameters, led to the extraction of two main factors. The first principal component (factor 1) accounted for 44-57% of the variance in the data. The second principal component (factor 2) explained 29-33% of data variance. Moreover, the total data variance explained by the first two factors was at the level of 73-90%. More importantly, the PCA analysis of the HPLC retention data and structural parameters allows the segregation of circulatory system drugs according to their pharmacological (cardiovascular) properties as shown by the distribution of the individual drugs on the plane determined by the two principal components (factors 1 and 2). PMID:20717530

Stasiak, Jolanta; Koba, Marcin; Bober, Leszek; Baczek, Tomasz

2010-01-01

46

Mathematical biomarkers for the autonomic regulation of cardiovascular system.  

PubMed

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

47

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.

Campos, Luciana A.; Pereira, Valter L.; Muralikrishna, Amita; Albarwani, Sulayma; Bras, Susana; Gouveia, Sonia

2013-01-01

48

Cell death in the cardiovascular system  

PubMed Central

Cell death is important for both development and tissue homeostasis in the adult. As such, it is tightly controlled and deregulation is associated with diverse pathologies; for example, regulated cell death is involved in vessel remodelling during development or following injury, but deregulated death is implicated in pathologies such as atherosclerosis, aneurysm formation, ischaemic and dilated cardiomyopathies and infarction. We describe the mechanisms of cell death and its role in the normal physiology and various pathologies of the cardiovascular system.

Clarke, Murray; Bennett, Martin; Littlewood, Trevor

2007-01-01

49

Natriuretic Peptide system and cardiovascular disease.  

PubMed

The mammalian Natriuretic Peptide (NP) system consists of neuro-hormones, such as atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), c-type natriuretic peptide (CNP), and the N-Terminal fragment of BNP (NT-pro-BNP). In response to some cardiovascular derangement the heart (acting as an endocrine organ), brain and other structures secretes natriuretic peptides in an attempt to restore normal circulatory conditions. Their actions are modulated through membrane-bound guanylyl cyclased (GC) receptors. They induce diuresis, natriuresis and vasodilation in the presence of congestive heart failure. These neuro-hormones also play a role in the suppression of neointimal formation after vascular injury. In addition, they act as antifibrotic and antihypertrophic agents preventing cardiac remodeling after myocardial infarction. Further, NP have diagnostic and prognostic role in heart failure, vasoconstriction, left ventricular late remodeling after MI and others. At present, some drugs such as Nesiritide, NEP inhibitors and vasopeptidase inhibitors were synthetized from NP, to antagonize these cardiovascular derengements. In future, it will be possibile to elaborate some drugs similar to petidase inhibitors and some CNP-like drugs able to reduce many symptoms of cardiovascular derangements without significant side effects. PMID:21042458

Federico, Cacciapuoti

2010-03-01

50

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

51

User's instructions for the high speed version of the cardiovascular exercise model  

NASA Technical Reports Server (NTRS)

A mathematical model and digital computer simulation of the human cardiovascular system and its controls were developed to simulate transient responses to bicycle ergometer exercise. The purpose of the model was to provide a method to analyze cardiovascular control hypotheses which cannot be easily tested in an animal or human or in a spaceflight environment.

Croston, R. C.

1973-01-01

52

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

53

Targets of oxidative stress in cardiovascular system.  

PubMed

Although oxidants such as superoxide (O2.) and hydrogen peroxide (H2O2) play a role in host-mediated destruction of foreign pathogens yet excessive generation of oxidants may lead to a variety of pathological complications in the cardiovascular system. An important mechanism by which oxidants cause dysfunction of the cardiovascular system appears to be due to the increase in intracellular free Ca2+ concentration. Oxidants cause cellular Ca2+ mobilization by modulating activities of a variety of regulators such as Na+/H+ and Na+/Ca2+ exchangers, Na+/K+ ATPase and Ca2+ ATPase and Ca2+ channels that are associated with Ca2+ transport in the plasma membrane and the sarco(endo)plasmic reticular membrane of myocardial cells. Recent research have suggested that the increase in Ca2+ level by oxidants plays a pivotal role in inducing several protein kinases such as protein kinase C, tyrosine kinase and mitogen activated protein kinases. Oxidant-mediated alteration of different signal transduction systems and their interations eventually regulate a variety of pathological conditions such as atherosclerosis, apoptosis and necrosis in the myocardium. PMID:9788737

Chakraborti, T; Ghosh, S K; Michael, J R; Batabyal, S K; Chakraborti, S

1998-10-01

54

Subject-specific cardiovascular system model-based identification and diagnosis of septic shock with a minimally invasive data set: animal experiments and proof of concept.  

PubMed

A cardiovascular system (CVS) model and parameter identification method have previously been validated for identifying different cardiac and circulatory dysfunctions in simulation and using porcine models of pulmonary embolism, hypovolemia with PEEP titrations and induced endotoxic shock. However, these studies required both left and right heart catheters to collect the data required for subject-specific monitoring and diagnosis-a maximally invasive data set in a critical care setting although it does occur in practice. Hence, use of this model-based diagnostic would require significant additional invasive sensors for some subjects, which is unacceptable in some, if not all, cases. The main goal of this study is to prove the concept of using only measurements from one side of the heart (right) in a 'minimal' data set to identify an effective patient-specific model that can capture key clinical trends in endotoxic shock. This research extends existing methods to a reduced and minimal data set requiring only a single catheter and reducing the risk of infection and other complications-a very common, typical situation in critical care patients, particularly after cardiac surgery. The extended methods and assumptions that found it are developed and presented in a case study for the patient-specific parameter identification of pig-specific parameters in an animal model of induced endotoxic shock. This case study is used to define the impact of this minimal data set on the quality and accuracy of the model application for monitoring, detecting and diagnosing septic shock. Six anesthetized healthy pigs weighing 20-30 kg received a 0.5 mg kg(-1) endotoxin infusion over a period of 30 min from T0 to T30. For this research, only right heart measurements were obtained. Errors for the identified model are within 8% when the model is identified from data, re-simulated and then compared to the experimentally measured data, including measurements not used in the identification process for validation. Importantly, all identified parameter trends match physiologically and clinically and experimentally expected changes, indicating that no diagnostic power is lost. This work represents a further with human subjects validation for this model-based approach to cardiovascular diagnosis and therapy guidance in monitoring endotoxic disease states. The results and methods obtained can be readily extended from this case study to the other animal model results presented previously. Overall, these results provide further support for prospective, proof of concept clinical testing with humans. PMID:21098941

Chase, J Geoffrey; Lambermont, Bernard; Starfinger, Christina; Hann, Christopher E; Shaw, Geoffrey M; Ghuysen, Alexandre; Kolh, Philippe; Dauby, Pierre C; Desaive, Thomas

2011-01-01

55

Functional food science and the cardiovascular system.  

PubMed

Cardiovascular disease has a multifactorial aetiology, as is illustrated by the existence of numerous risk indicators, many of which can be influenced by dietary means. It should be recalled, however, that only after a cause-and-effect relationship has been established between the disease and a given risk indicator (called a risk factor in that case), can modifying this factor be expected to affect disease morbidity and mortality. In this paper, effects of diet on cardiovascular risk are reviewed, with special emphasis on modification of the plasma lipoprotein profile and of hypertension. In addition, dietary influences on arterial thrombotic processes, immunological interactions, insulin resistance and hyperhomocysteinaemia are discussed. Dietary lipids are able to affect lipoprotein metabolism in a significant way, thereby modifying the risk of cardiovascular disease. However, more research is required concerning the possible interactions between the various dietary fatty acids, and between fatty acids and dietary cholesterol. In addition, more studies are needed with respect to the possible importance of the postprandial state. Although in the aetiology of hypertension the genetic component is definitely stronger than environmental factors, some benefit in terms of the development and coronary complications of atherosclerosis in hypertensive patients can be expected from fatty acids such as alpha-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid. This particularly holds for those subjects where the hypertensive mechanism involves the formation of thromboxane A2 and/or alpha 1-adrenergic activities. However, large-scale trials are required to test this contention. Certain aspects of blood platelet function, blood coagulability, and fibrinolytic activity are associated with cardiovascular risk, but causality has been insufficiently proven. Nonetheless, well-designed intervention studies should be initiated to further evaluate such promising dietary components as the various n-3 and n-6 fatty acids and their combination, antioxidants, fibre, etc. for their effect on processes participating in arterial thrombus formation. Long-chain polyenes of the n-3 family and antioxidants can modify the activity of immunocompetent cells, but we are at an early stage of examining the role of immune function on the development of atherosclerotic plaques. Actually, there is little, if any, evidence that dietary modulation of immune system responses of cells participating in atherogenesis exerts beneficial effects. Although it seems feasible to modulate insulin sensitivity and subsequent cardiovascular risk factors by decreasing the total amount of dietary fat and increasing the proportion of polyunsaturated fatty acids, additional studies on the efficacy of specific fatty acids, dietary fibre, and low-energy diets, as well as on the mechanisms involved are required to understand the real function of these dietary components. Finally, dietary supplements containing folate and vitamins B6 and/or B12 should be tested for their potential to reduce cardiovascular risk by lowering the plasma level of homocysteine. PMID:9849356

Hornstra, G; Barth, C A; Galli, C; Mensink, R P; Mutanen, M; Riemersma, R A; Roberfroid, M; Salminen, K; Vansant, G; Verschuren, P M

1998-08-01

56

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

57

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

Microsoft Academic Search

Exposure to particulate matter (PM) has been associated with increased morbidity and mortality among individuals with cardiovascular disease. It is hypothesized that systemic alterations occur concurrent to pulmonary injury\\/inflammation, and contribute to cardiac events in compromised hosts. We explored this hypothesis using a rat model for human hypertension and cardiovascular disease (spontaneously hypertensive, SH), and normotensive Wistar Kyoto (WKY) rats.

Urmila P. Kodavanti; Mette C. Schladweiler; Allen D. Ledbetter; Russ Hauser; David C. Christiani; John McGee; Judy R. Richards; Daniel L. Costa

2002-01-01

58

Development of the National Cardiovascular Information System (NCIS) in Ireland  

Microsoft Academic Search

The National Cardiovascular Information System (NCIS) is described as a series of integrated cardiology care registers designed to collect data on the clinical care of patients with cardiac disease in acute hospitals in Ireland. The aim of this paper is to provide information on the National Cardiovascular Information System (NCIS), including the background to the development of the system and

M. Rachel Flynn; Moira Lonergan; Peter Kearney; Emer Shelley

2005-01-01

59

A mock circulation model for cardiovascular device evaluation.  

PubMed

The aim of this study was to develop an integrated mock circulation system that functions in a physiological manner for testing cardiovascular devices under well-controlled circumstances. In contrast to previously reported mock loops, the model includes a systemic, pulmonary, and coronary circulation, an elaborate heart contraction model, and a realistic heart rate control model. The behavior of the presented system was tested in response to changes in left ventricular contractile states, loading conditions, and heart rate. For validation purposes, generated hemodynamic parameters and responses were compared to literature. The model was implemented in a servo-motor driven mock loop, together with a relatively simple lead-lag controller. The pressure and flow signals measured closely mimicked human pressure under both physiological and pathological conditions. In addition, the system's response to changes in preload, afterload, and heart rate indicate a proper implementation of the incorporated feedback mechanisms (frequency and cardiac function control). Therefore, the presented mock circulation allows for generic in vitro testing of cardiovascular devices under well-controlled circumstances. PMID:24622168

Schampaert, S; Pennings, K A M A; van de Molengraft, M J G; Pijls, N H J; van de Vosse, F N; Rutten, M C M

2014-04-01

60

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

61

Modeling of Cardiovascular Response to Weightlessness.  

National Technical Information Service (NTIS)

It was the hypothesis of this Project that the Simple lack of hydrostatic pressure in microgravity generates several purely physical reactions that underlie and may explain, in part, the cardiovascular response to weightlessness. For instance, hydrostatic...

M. K. Sharp

1999-01-01

62

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

63

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

64

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

65

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

Microsoft Academic Search

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

Alexander Roytvarf; Vladimir Shusterman

2008-01-01

66

Diabetes and Cardiovascular Autonomic Dysfunction: Application of Animal Models  

PubMed Central

When diabetes is associated with cardiovascular autonomic dysfunction, there is a poor prognosis and increased morbidity and mortality. Information on the mechanisms of diabetes-associated autonomic dysfunction has been provided by advanced studies using physiological, pharmacological, anatomical and molecular methods in experimental animal models of insulin deficiency and resistance. This has been augmented by new approaches which combine diabetes induction with genetically modified animal models. The aim of this review is to outline and discuss the animal models used for the study of insulin deficiency and insulin resistance with a focus on autonomic neural interactions. The goal is to better understand the clinical relevance of cardiovascular autonomic dysfunction associated with diabetes.

De Angelis, Katia; Irigoyen, Maria Claudia; Morris, Mariana

2009-01-01

67

Computational modeling of cardiovascular response to orthostatic stress  

NASA Technical Reports Server (NTRS)

The objective of this study is to develop a model of the cardiovascular system capable of simulating the short-term (< or = 5 min) transient and steady-state hemodynamic responses to head-up tilt and lower body negative pressure. The model consists of a closed-loop lumped-parameter representation of the circulation connected to set-point models of the arterial and cardiopulmonary baroreflexes. Model parameters are largely based on literature values. Model verification was performed by comparing the simulation output under baseline conditions and at different levels of orthostatic stress to sets of population-averaged hemodynamic data reported in the literature. On the basis of experimental evidence, we adjusted some model parameters to simulate experimental data. Orthostatic stress simulations are not statistically different from experimental data (two-sided test of significance with Bonferroni adjustment for multiple comparisons). Transient response characteristics of heart rate to tilt also compare well with reported data. A case study is presented on how the model is intended to be used in the future to investigate the effects of post-spaceflight orthostatic intolerance.

Heldt, Thomas; Shim, Eun B.; Kamm, Roger D.; Mark, Roger G.

2002-01-01

68

Adipokines and the cardiovascular system: mechanisms mediating health and disease.  

PubMed

This review focuses on the role of adipokines in the maintenance of a healthy cardiovascular system, and the mechanisms by which these factors mediate the development of cardiovascular disease in obesity. Adipocytes are the major cell type comprising the adipose tissue. These cells secrete numerous factors, termed adipokines, into the blood, including adiponectin, leptin, resistin, chemerin, omentin, vaspin, and visfatin. Adipose tissue is a highly vascularised endocrine organ, and different adipose depots have distinct adipokine secretion profiles, which are altered with obesity. The ability of many adipokines to stimulate angiogenesis is crucial for adipose tissue expansion; however, excessive blood vessel growth is deleterious. As well, some adipokines induce inflammation, which promotes cardiovascular disease progression. We discuss how these 7 aforementioned adipokines act upon the various cardiovascular cell types (endothelial progenitor cells, endothelial cells, vascular smooth muscle cells, pericytes, cardiomyocytes, and cardiac fibroblasts), the direct effects of these actions, and their overall impact on the cardiovascular system. These were chosen, as these adipokines are secreted predominantly from adipocytes and have known effects on cardiovascular cells. PMID:22646022

Northcott, Josette M; Yeganeh, Azadeh; Taylor, Carla G; Zahradka, Peter; Wigle, Jeffrey T

2012-08-01

69

Stabilizing control for a pulsatile cardiovascular mathematical model.  

PubMed

In this paper, we develop a pulsatile model for the cardiovascular system which describes the reaction of this system to a submaximal constant workload imposed on a person at a bicycle ergometer test after a period of rest. Furthermore, the model should allow to use measurements for the pulsatile pressure in fingertips which provide information on the diastolic and the systolic pressure for parameter estimation. Based on the assumption that the baroreceptor loop is the essential control loop in this case, we design a stabilizing feedback control for the pulsatile model which is obtained by solving a linear-quadratic regulator problem for the linearization of a non-pulsatile counterpart of the pulsatile model. We also investigate the behavior of the model with respect to changes in the weight of the term in the cost functional for the linear-quadratic regulator problem which penalizes the deviation of the momentary pressure in the aorta from the pressure at the stationary situation which should be obtained. PMID:24789569

de Los Reyes, Aurelio A; Jung, Eunok; Kappel, Franz

2014-06-01

70

A cardiovascular monitoring system used in conscious cynomolgus monkeys for regulatory safety pharmacology: Part 2: Pharmacological validation  

Microsoft Academic Search

Introduction: This project addresses the validation study design of a test system using a telemetered non-human primate model for cardiovascular safety pharmacology evaluation. Methods: In addition to non-pharmacological validation including installation and operation qualifications, performance qualification (locomotor activity and cardiovascular evaluations) was completed on free-moving cynomolgus monkeys by quantifying the degree of cardiovascular response measured by the telemetric device to

Simon Authier; Jean-Francois Tanguay; Dominique Gauvin; Rocky Di Fruscia; Eric Troncy

2007-01-01

71

Gravitational force and the cardiovascular system  

NASA Technical Reports Server (NTRS)

Ground-based simulation studies have been conducted to clarify the problems of the cardiovascular adaptation to alterations in gravitational force. Simulated microgravity experiments resulted in increases in cardiac stretch, urine flow, and sodium excretion, which were accompanied by lower plasma renin, aldosterone, and ADH. There appears to be a decrease in plasma volume as well as in sympathetic tone after 2-3 days of 0 Gz. Complete adjustment to 0 Gz is found within 8 h without a decrease in plasma volume, when subjects are allowed to dehydrate mildly.

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

1991-01-01

72

Reactive Oxygen Species and the Cardiovascular System  

PubMed Central

Ever since the discovery of free radicals, many hypotheses on the deleterious actions of reactive oxygen species (ROS) have been proposed. However, increasing evidence advocates the necessity of ROS for cellular homeostasis. ROS are generated as inherent by-products of aerobic metabolism and are tightly controlled by antioxidants. Conversely, when produced in excess or when antioxidants are depleted, ROS can inflict damage to lipids, proteins, and DNA. Such a state of oxidative stress is associated with many pathological conditions and closely correlated to oxygen consumption. Although the deleterious effects of ROS can potentially be reduced by restoring the imbalance between production and clearance of ROS through administration of antioxidants (AOs), the dosage and type of AOs should be tailored to the location and nature of oxidative stress. This paper describes several pathways of ROS signaling in cellular homeostasis. Further, we review the function of ROS in cardiovascular pathology and the effects of AOs on cardiovascular outcomes with emphasis on the so-called oxidative paradox.

Taverne, Yannick J. H. J.; Bogers, Ad J. J. C.; Duncker, Dirk J.; Merkus, Daphne

2013-01-01

73

Nonviral gene therapy targeting cardiovascular system.  

PubMed

The goal of gene therapy is either to introduce a therapeutic gene into or replace a defective gene in an individual's cells and tissues. Gene therapy has been urged as a potential method to induce therapeutic angiogenesis in ischemic myocardium and peripheral tissues after extensive investigation in recent preclinical and clinical studies. A successful gene therapy mainly relies on the development of the gene delivery vector. Developments in viral and nonviral vector technology including cell-based gene transfer will further improve transgene delivery and expression efficiency. Nonviral approaches as alternative gene delivery vehicles to viral vectors have received significant attention. Recently, a simple and safe approach of gene delivery into target cells using naked DNA has been improved by combining several techniques. Among the physical approaches, ultrasonic microbubble gene delivery, with its high safety profile, low costs, and repeatable applicability, can increase the permeability of cell membrane to macromolecules such as plasmid DNA by its bioeffects and can provide as a feasible tool in gene delivery. On the other hand, among the promising areas for gene therapy in acquired diseases, ischemic cardiovascular diseases have been widely studied. As a result, gene therapy using advanced technology may play an important role in this regard. The aims of this review focus on understanding the cellular and in vivo barriers in gene transfer and provide an overview of currently used chemical vectors and physical tools that are applied in nonviral cardiovascular gene transfer. PMID:22821991

Su, Cheng-Huang; Wu, Yih-Jer; Wang, Hsueh-Hsiao; Yeh, Hung-I

2012-09-15

74

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.

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

2013-01-01

75

Cardiovascular complications in diabetes: lessons from animal models.  

PubMed

Micro- and macro-vascular complications are the leading causes of morbidity and mortality in type 1 and type 2 diabetic patients. Despite the vast clinical experience linking diabetic metabolic abnormalities to cardiovascular lesions, the molecular basis of individual susceptibility to diabetic cardiovascular injury is still largely unknown. Significant advances in this area may come from studies on suitable animal models. Although no animal model can accurately reproduce the human disease, experimental studies in animals have the great advantage to eliminate factors such as ethnicity, economic and geographic variables, drug interactions, diet, gender and age differences that importantly limit clinical studies. Indeed, appropriate animal models have provided important information on genetic and environmental risks of diabetes, and helped to dissect molecular mechanisms underlying the development, progression and therapeutic control of this disease. Unfortunately, none of the diabetic models presently available fully mimics the human syndrome. Therefore, the current knowledge on the pathogenesis of cardiovascular complications relies on the evaluation of distinct phenotypes from various diabetic models. In addition to strains prone to diabetes, this disease can be induced by surgical, pharmacological or genetic manipulation in several animal species. Rodents are the most used, although some studies are still performed in larger animals as rabbits, cats, pigs or monkeys. Far from being exhaustive, this work should serve as a general overview of the most relevant clues provided by major species and models for the overall comprehension of cardiovascular complications in type 1 and type 2 diabetes. PMID:21466471

Potenza, M A; Nacci, C; Gagliardi, S; Montagnani, M

2011-01-01

76

Protein tyrosine phosphorylation in cardiovascular system.  

PubMed

Protein tyrosine phosphorylation is believed to play a central role in signaling pathways initiated by growth factor receptor activation. Recent studies have shown that various vasoactive peptides, in addition to eliciting a contractile response, also serve as growth factors for vascular smooth muscle ans stimulate tyrosyl phosphorylation of several endogenous proteins. Some of these proteins have been identified and are similar to those stimulated by growth factor receptor activation. Furthermore, evidence is also accumulating to support an involvement of protein tyrosine phosphorylation in acute action of growth factors and vasoactive peptides on smooth an muscle contractility. This review still briefly summarize the recent work on vasoactive peptide-mediated protein tyrosine phosphorylation in cardiovascular tissues and its potential functional significance. PMID:8569753

Srivastava, A K

1995-01-01

77

Clinical Application of Stem Cells in the Cardiovascular System  

NASA Astrophysics Data System (ADS)

Regenerative medicine encompasses "tissue engineering" - the in vitro fabrication of tissues and/or organs using scaffold material and viable cells - and "cell therapy" - the transplantation or manipulation of cells in diseased tissue in vivo. In the cardiovascular system, tissue engineering strategies are being pursued for the development of viable replacement blood vessels, heart valves, patch material, cardiac pacemakers and contractile myocardium. Anecdotal clinical applications of such vessels, valves and patches have been described, but information on systematic studies of the performance of such implants is not available, yet. Cell therapy for cardiovascular regeneration, however, has been performed in large series of patients, and numerous clinical studies have produced sometimes conflicting results. The purpose of this chapter is to summarize the clinical experience with cell therapy for diseases of the cardiovascular system, and to analyse possible factors that may influence its outcome.

Stamm, Christof; Klose, Kristin; Choi, Yeong-Hoon

78

Validity of Cardiovascular Risk Prediction Models in Kidney Transplant Recipients  

PubMed Central

Background. Predicting cardiovascular risk is of great interest in renal transplant recipients since cardiovascular disease is the leading cause of mortality. Objective. To conduct a systematic review to assess the validity of cardiovascular risk prediction models in this population. Methods. Five databases were searched (MEDLINE, EMBASE, SCOPUS, CINAHL, and Web of Science) and cohort studies with at least one year of follow-up were included. Variables that described population characteristics, study design, and prognostic performance were extracted. The Quality in Prognostic Studies (QUIPS) tool was used to evaluate bias. Results. Seven studies met the criteria for inclusion, of which, five investigated the Framingham risk score and three used a transplant-specific model. Sample sizes ranged from 344 to 23,575, and three studies lacked sufficient event rates to confidently reach conclusion. Four studies reported discrimination (as measured by c-statistic), which ranged from 0.701 to 0.75, while only one risk model was both internally and externally validated. Conclusion. The Framingham has underestimated cardiovascular events in renal transplant recipients, but these studies have not been robust. A risk prediction model has been externally validated at least on one occasion, but comprehensive validation in multiple cohorts and impact analysis are recommended before widespread clinical application is advocated.

Stewart, Samuel Alan; Shoker, Ahmed

2014-01-01

79

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.

2014-01-01

80

The emerging role of the endocannabinoid system in cardiovascular disease  

PubMed Central

Endocannabinoids are endogenous bioactive lipid mediators present both in the brain and various peripheral tissues, which exert their biological effects via interaction with specific G-protein-coupled cannabinoid receptors, the CB1 and CB2. Pathological overactivation of the endocannabinoid system (ECS) in various forms of shock and heart failure may contribute to the underlying pathology and cardiodepressive state by the activation of the cardiovascular CB1 receptors. Furthermore, tonic activation of CB1 receptors by endocannabinoids has also been implicated in the development of various cardiovascular risk factors in obesity/metabolic syndrome and diabetes, such as plasma lipid alterations, abdominal obesity, hepatic steatosis, inflammation, and insulin and leptin resistance. In contrast, activation of CB2 receptors in immune cells exerts various immunomodulatory effects, and the CB2 receptors in endothelial and inflammatory cells appear to limit the endothelial inflammatory response, chemotaxis, and inflammatory cell adhesion and activation in atherosclerosis and reperfusion injury. Here, we will overview the cardiovascular actions of endocannabinoids and the growing body of evidence implicating the dysregulation of the ECS in a variety of cardiovascular diseases. We will also discuss the therapeutic potential of the modulation of the ECS by selective agonists/antagonists in various cardiovascular disorders associated with inflammation and tissue injury, ranging from myocardial infarction and heart failure to atherosclerosis and cardiometabolic disorders.

2009-01-01

81

Stress, depression and cardiovascular dysregulation: a review of neurobiological mechanisms and the integration of research from preclinical disease models.  

PubMed

Bidirectional associations between mood disorders and cardiovascular diseases are extensively documented. However, the precise physiological and biochemical mechanisms that underlie such relationships are not well understood. This review focuses on the neurobiological processes and mediators that are common to both mood and cardiovascular disorders. The discussion places an emphasis on the role of exogenous stressors in addition to: (a) neuroendocrine and neurohumoral changes involving dysfunction of the hypothalamic-pituitary-adrenal axis and the activation of the renin-angiotensin-aldosterone system, (b) immune alterations including activation of pro-inflammatory cytokines, (c) autonomic and cardiovascular dysregulation including increased sympathetic drive, withdrawal of parasympathetic tone, cardiac rate and rhythm disturbances, and altered baroreceptor reflex function, (d) central neurotransmitter system dysfunction involving the dopamine, norepinephrine and serotonin systems, and (e) behavioral changes including fatigue and physical inactivity. The review also discusses experimental investigations using preclinical disease models to elucidate the neurobiological mechanisms underlying the link between mood disorders and cardiovascular disease. These include: (a) the chronic mild stress model of depression, (b) a model of congestive heart failure, (c) a model of cardiovascular deconditioning, (d) pharmacological manipulations of body fluid and sodium balance, and (e) pharmacological manipulations of the central serotonergic system. In combination with an extensive human research literature, the investigation of mechanisms underlying mood and cardiovascular regulation using animal models will enhance understanding the association between depression and cardiovascular disease. This will ultimately promote the development of better treatments and interventions for individuals with co-morbid psychological and somatic pathologies. PMID:19116888

Grippo, Angela J; Johnson, Alan Kim

2009-01-01

82

Pharmacokinetic-pharmacodynamic modelling of the cardiovascular effects of drugs - method development and application to magnesium in sheep  

PubMed Central

Background There have been few reports of pharmacokinetic models that have been linked to models of the cardiovascular system. Such models could predict the cardiovascular effects of a drug under a variety of circumstances. Limiting factors may be the lack of a suitably simple cardiovascular model, the difficulty in managing extensive cardiovascular data sets, and the lack of physiologically based pharmacokinetic models that can account for blood flow changes that may be caused by a drug. An approach for addressing these limitations is proposed, and illustrated using data on the cardiovascular effects of magnesium given intravenously to sheep. The cardiovascular model was based on compartments for venous and arterial blood. Blood flowed from arterial to venous compartments via a passive flow through a systemic vascular resistance. Blood flowed from venous to arterial via a pump (the heart-lung system), the pumping rate was governed by the venous pressure (Frank-Starling mechanism). Heart rate was controlled via the difference between arterial blood pressure and a set point (Baroreceptor control). Constraints were made to pressure-volume relationships, pressure-stroke volume relationships, and physical limits were imposed to produce plausible cardiac function curves and baseline cardiovascular variables. "Cardiovascular radar plots" were developed for concisely displaying the cardiovascular status. A recirculatory kinetic model of magnesium was developed that could account for the large changes in cardiac output caused by this drug. Arterial concentrations predicted by the kinetic model were linked to the systemic vascular resistance and venous compliance terms of the cardiovascular model. The kinetic-dynamic model based on a training data set (30 mmol over 2 min) was used to predict the results for a separate validation data set (30 mmol over 5 min). Results The kinetic-dynamic model was able to describe the training data set. A recirculatory kinetic model was a good description of the acute kinetics of magnesium in sheep. The volume of distribution of magnesium in the lungs was 0.89 L, and in the body was 4.02 L. A permeability term (0.59 L min-1) described the distribution of magnesium into a deeper (probably intracellular) compartment. The final kinetic-dynamic model was able to predict the validation data set. The mean prediction error for the arterial magnesium concentrations, cardiac output and mean arterial blood pressure for the validation data set were 0.02, 3.0 and 6.1%, respectively. Conclusion The combination of a recirculatory model and a simple two-compartment cardiovascular model was able to describe and predict the kinetics and cardiovascular effects of magnesium in sheep.

Upton, Richard N; Ludbrook, Guy L

2005-01-01

83

Electronic circuit detects left ventricular ejection events in cardiovascular system  

NASA Technical Reports Server (NTRS)

Electronic circuit processes arterial blood pressure waveform to produce discrete signals that coincide with beginning and end of left ventricular ejection. Output signals provide timing signals for computers that monitor cardiovascular systems. Circuit operates reliably for heart rates between 50 and 200 beats per minute.

Gebben, V. D.; Webb, J. A., Jr.

1972-01-01

84

Effects of lower-body negative pressure on blood flow with applications to the human cardiovascular system  

Microsoft Academic Search

The paper reports a theoretical investigation into the effects of lower-body negative pressure on blood flow through the human\\u000a cardiovascular system. The human cardiovascular system is modelled as a closed network of arteries, arterioles, capillaries,\\u000a venules and veins of different lengths and cross-sections. The pumping action is provided by the contraction of the ventricles.\\u000a The model has been analysed using

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

1993-01-01

85

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.

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

2013-01-01

86

A cardiovascular monitoring system in conscious cynomolgus monkeys for regulatory safety pharmacology  

Microsoft Academic Search

Introduction: This project addresses the validation study design of a test system using a telemetered non-human primate model for cardiovascular safety pharmacology evaluation. Methods: The validation provided by the supplier evaluated installation (IQ) and operation (OQ) qualifications. This protocol was completed with tests evaluating electronic data management and accuracy and precision of transmitter (n=4) measurements for temperature and pressure criteria

Simon Authier; Jean-Francois Tanguay; Dominique Gauvin; Rocky Di Fruscia; Sebastien Fournier; Fernando Chaurand; Eric Troncy

2007-01-01

87

[Thalassotherapy effect on cardiovascular system and cardiac rhythm variability].  

PubMed

A complex study of physiological parameters allowed us to analyse reactions of cardiovascular system to dipping into a hot water varying in salt concentrations. These reactions differ from those to dipping into cold water. Dipping into hot water leads to depression of the tonicity of parasympathic nervous system in such a manner that increased heart rate does not cause vascular contraction. Effects of water salt concentrations on the above parameters need further investigations. PMID:15759468

Merati, J; Solimene, U; Cherina, A; Piccini, J; Vaistainas, A

2005-01-01

88

A new test circulatory system for research in cardiovascular engineering  

Microsoft Academic Search

A new test circulatory system (TCS) has been developed for thein vitro testing of artificial hearts (AH) and for research in cardiovascular engineering, when connected to an AH that mimics the\\u000a natural heart. The TCS is controlled by five variables whereby the slopes of the systemic and pulmonary venous return curves\\u000a and the mean circulatory pressure can be fixed. It

M. Arabia; T. Akutsu

1984-01-01

89

Mathematical modeling of acute and chronic cardiovascular changes during Extended Duration Orbiter (EDO) flights  

NASA Technical Reports Server (NTRS)

The purpose of NASA's Extended Duration Orbiter program is a gradual extension of the capabilities of the Space Shuttle Orbiter beyond its current 7-10 day limit on mission duration, as warranted by deepening understanding of the long-term physiological effects of weightlessness. Attention is being given to the cardiovascular problem of orthostatic tolerance loss due to its adverse effects on crew performance and health during reentry and initial readaptation to earth gravity. An account is given of the results of the application of proven mathematical models of circulatory and cardiovascular systems under microgravity conditions.

White, Ronald J.; Leonard, Joel I.; Srinivasan, R. Srini; Charles, John B.

1991-01-01

90

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.

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

2013-01-01

91

Hardware-in-the-loop-simulation of the cardiovascular system, with assist device testing application.  

PubMed

This paper presents a technique for evaluating the performance of biomedical devices by combining physical (mechanical) testing with a numerical, computerised model of a biological system. This technique is developed for evaluation of a cardiac assist device prior to in vivo trials. This device will wrap around a failing heart and provide physical beating assistance (dynamic cardiac compression). In vitro, the device to be tested is placed around a simulator comprising a mechanical simulation of the beating ventricles. This hardware model interfaces with a computerised (software) model of the cardiovascular system. In real time the software model calculates the effect of the assistance on the cardiovascular system and controls the beating motion of the hardware heart simulator appropriately. The software model of the cardiovascular system can represent ventricles in various stages of heart failure, and/or hardened or congested blood vessels as required. The software displays physiological traces showing the cardiac output, depending on the natural function of the modelled heart together with the physical assist power provided. This system was used to evaluate the effectiveness of control techniques applied to the assist device. Experimental results are presented showing the efficacy of prototype assist on healthy and weakened hearts, and the effect of asynchronous assist. PMID:16815728

Hanson, B M; Levesley, M C; Watterson, K; Walker, P G

2007-04-01

92

Racial Differences in Ideal Cardiovascular Health Metrics Among Mississippi Adults, 2009 Mississippi Behavioral Risk Factor Surveillance System  

PubMed Central

Introduction Cardiovascular disease is a leading cause of death and health disparities in Mississippi. Identifying populations with poor cardiovascular health may help direct interventions toward those populations disproportionately affected, which may ultimately increase cardiovascular health and decrease prominent disparities. Our objective was to assess racial differences in the prevalence of cardiovascular health metrics among Mississippi adults. Methods We used data from the 2009 Mississippi Behavioral Risk Factor Surveillance System to determine age-standardized prevalence estimates and 95% confidence intervals of cardiovascular health metrics among 2,003 black and 5,125 white adults. Logistic regression models were used to evaluate the relationship between race and cardiovascular health metrics. The mean cardiovascular metrics score and percentage of the population with ideal and poor cardiovascular health were calculated by subgroup. Results Approximately 1.3% of blacks and 2.6% of whites exhibited ideal levels of all 7 cardiovascular health metrics. The prevalence of 4 of the 7 cardiovascular health metrics was significantly lower among the total population of blacks than among whites, including a normal body mass index (20.8% vs 32.3%, P < .001), no history of diabetes (85.1% vs 91.3%, P < .001), no history of hypertension (53.9% vs 67.9%, P < .001), and physical activity (52.8% vs 62.2%, P < .001). The logistic regression models revealed significant race-by-sex interactions; differences between blacks and whites for normal body mass index, no history of diabetes mellitus, and no current smoking were found among women but not among men. Conclusion Cardiovascular health is poor among Mississippi adults overall, and racial differences exist.

Gamble, Abigail; Mendy, Vincent

2013-01-01

93

SELECTIVITY IN THE STUDY OF THE CARDIOVASCULAR SYSTEM  

PubMed Central

The principle of selectivity in the roentgenology of the cardiovascular system is now firmly established. The chambers of the heart and certain vascular beds lend themselves admirably to selective catheter or needle study, without the necessity of perfusing large segments of the cardiovascular bed which are irrelevant to a particular study. A technique of percutaneous transfemoral selective ciné coronary arteriography has been developed and applied to clinical subjects. Nevertheless, selectivity has specific limitations, and the use of the selective versus the nonselective approach must be weighed in each case, with the status of the patient as well as the requirements of the diagnostic investigation taken into account in reaching a decision. ImagesFigure 1.Figure 2.Figure 3.Figure 4.Figure 5.Figure 6A.Figure 6B.Figure 7.Figure 8.Figure 9.Figure 10.Figure 11.

Abrams, Herbert L.

1962-01-01

94

The human cardiovascular system in the absence of gravity  

NASA Technical Reports Server (NTRS)

The data collected from a Space Shuttle crew to investigate cardiovascular changes due to microgravity are presented. The experimental procedures which involved preflight, immediate postflight, and one week following postflight echocardiograms of 13 individuals are described. The immediate postflight results reveal a 20 percent decrease in stroke volume, a 16 percent decrease in left ventricular diastolic volume index (LVDVI), no change in systolic volume, blood pressure, or cardiac index, and a 24 percent increase in heart rate. One week later a 17 percent stroke volume increase, a 29 percent increase in cardiac index, and normal blood pressure, and LVDVI were observed. It is concluded that upon reexposure to gravity a readaptation process for the cardiovascular system occurs.

Bungo, M. W.; Charles, J. B.

1985-01-01

95

Exercise protects the cardiovascular system: effects beyond traditional risk factors  

PubMed Central

In humans, exercise training and moderate to high levels of physical activity are protective against cardiovascular disease. In fact they are ?40% more protective than predicted based on the changes in traditional risk factors (blood lipids, hypertension, diabetes etc.) that they cause. In this review, we highlight the positive effects of exercise on endothelial function and the autonomic nervous system. We also ask if these effects alone, or in combination, might explain the protective effects of exercise against cardiovascular disease that appear to be independent of traditional risk factor modification. Our goal is to use selected data from our own work and that of others to stimulate debate on the nature and cause of the ‘risk factor gap’ associated with exercise and physical activity.

Joyner, Michael J; Green, Daniel J

2009-01-01

96

Glucocorticoids and the cardiovascular system: state of the art.  

PubMed

Glucocorticoids (GC) are drugs commonly used, by approximately 1% of the total adult population as anti-inflammatory and immunosuppressive therapies for asthma, inflammatory bowel disease, dermatological, ophthalmic, neurological, and rheumatic autoimmune diseases. Supporting evidence exists of GC use in both immune mediated and non-immune mediated heart disease. The molecular mechanisms by which GC induces immune-modulation and direct cardioprotection, are complex and not fully understood. We review herein, the current knowledge of GC use in various immune-mediated or non-immune mediated cardiovascular conditions. GC have been investigated in autoimmune, inflammatory and idiopathic heart diseases such as atrio-ventricular conduction abnormalities, rheumatic fever, myocarditis, dilated cardiomyopathy, Churg-Strauss syndrome, Kawasaki disease and sarcoidosis. GC therapy has been studied in non-autoimmune and non-inflammatory indications such as acute myocardial infarction, angina, postpericardiotomy syndrome and other pericardial diseases, endocarditis and cardiac amyloidosis, as well as in invasive cardiology, coronary interventions, and cardiopulmonary-bypass surgery. Despite GC's role as natural, physiologic regulators of the immune system, cardiovascular adverse outcomes may occur. Some of the well-known side effects of GC therapy involve bone, metabolic, and cardiovascular systems and include osteoporosis, fractures, dyslipidemia, diabetes, obesity, and hypertension. PMID:20977421

Nussinovitch, Udi; de Carvalho, Jozélio Freire; Pereira, Rosa Maria R; Shoenfeld, Yehuda

2010-01-01

97

The pig as a valuable model for testing the effect of resveratrol to prevent cardiovascular disease.  

PubMed

Resveratrol is a naturally occurring polyphenol found in the skin of red grapes, peanuts, and red wine that has been shown to modify many cardiovascular risk factors. Small animal models have been extensively used to investigate cardiovascular disease, but the results often fail to translate in clinical trials. Disease-specific pig models are emerging as clinically useful tools that may offer insight into cardiovascular disease and the effect of drugs such as resveratrol on cardiovascular health. In this paper, we discuss the advantage of using clinically relevant pig models of diabetes, hypercholesterolemia, and myocardial ischemia to investigate the role of resveratrol in cardiovascular disease prevention. PMID:23855475

Elmadhun, Nassrene Y; Sabe, Ashraf A; Robich, Michael P; Chu, Louis M; Lassaletta, Antonio D; Sellke, Frank W

2013-07-01

98

Chronic kidney disease: effects on the cardiovascular system.  

PubMed

Accelerated cardiovascular disease is a frequent complication of renal disease. Chronic kidney disease promotes hypertension and dyslipidemia, which in turn can contribute to the progression of renal failure. Furthermore, diabetic nephropathy is the leading cause of renal failure in developed countries. Together, hypertension, dyslipidemia, and diabetes are major risk factors for the development of endothelial dysfunction and progression of atherosclerosis. Inflammatory mediators are often elevated and the renin-angiotensin system is frequently activated in chronic kidney disease, which likely contributes through enhanced production of reactive oxygen species to the accelerated atherosclerosis observed in chronic kidney disease. Promoters of calcification are increased and inhibitors of calcification are reduced, which favors metastatic vascular calcification, an important participant in vascular injury associated with end-stage renal disease. Accelerated atherosclerosis will then lead to increased prevalence of coronary artery disease, heart failure, stroke, and peripheral arterial disease. Consequently, subjects with chronic renal failure are exposed to increased morbidity and mortality as a result of cardiovascular events. Prevention and treatment of cardiovascular disease are major considerations in the management of individuals with chronic kidney disease. PMID:17606856

Schiffrin, Ernesto L; Lipman, Mark L; Mann, Johannes F E

2007-07-01

99

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

100

Using a human cardiovascular-respiratory model to characterize cardiac tamponade and pulsus paradoxus  

Microsoft Academic Search

BACKGROUND: Cardiac tamponade is a condition whereby fluid accumulation in the pericardial sac surrounding the heart causes elevation and equilibration of pericardial and cardiac chamber pressures, reduced cardiac output, changes in hemodynamics, partial chamber collapse, pulsus paradoxus, and arterio-venous acid-base disparity. Our large-scale model of the human cardiovascular-respiratory system (H-CRS) is employed to study mechanisms underlying cardiac tamponade and pulsus

Deepa Ramachandran; Chuan Luo; Tony S Ma; John W Clark Jr

2009-01-01

101

Endocannabinoid system in cardiovascular disorders - new pharmacotherapeutic opportunities.  

PubMed

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 21(st) century. PMID:21966155

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

2011-07-01

102

Stress, depression, and cardiovascular dysregulation: A review of neurobiological mechanisms and the integration of research from preclinical disease models  

PubMed Central

A bidirectional association between mood disorders such as depression, and cardiovascular diseases such as myocardial infarction and congestive heart failure, has been described; however, the precise neurobiological mechanisms that underlie these associations have not been fully elucidated. This review is focused on the neurobiological processes and mediators that are common to both mood and cardiovascular disorders, with an emphasis on the role of exogenous stressors in addition to: (a) neuroendocrine and neurohumoral changes involving dysfunction of the hypothalamic-pituitary-adrenal axis and activation of the renin-angiotensin-aldosterone system, (b) immune alterations including activation of pro-inflammatory cytokines, (c) autonomic and cardiovascular dysregulation including increased sympathetic drive, withdrawal of parasympathetic tone, cardiac rate and rhythm disturbances, and altered baroreceptor reflex function, (d) central neurotransmitter system dysfunction including dopamine, norepinephrine and serotonin, and (e) behavioral changes including fatigue and physical inactivity. We also focus specifically on experimental investigations with preclinical disease models, conducted to elucidate the neurobiological mechanisms underlying the link between mood disorders and cardiovascular disease. These include: (a) the chronic mild stress model of depression, (b) a model of congestive heart failure, a model of cardiovascular deconditioning, (d) pharmacological manipulations of body fluid and sodium balance, and (e) pharmacological manipulations of the central serotonergic system. In combination with the extensive literature describing findings from human research, the investigation of mechanisms underlying mood and cardiovascular regulation using animal models will enhance our understanding of the association of depression and cardiovascular disease, and can promote the development of better treatments and interventions for individuals with these co-morbid conditions.

Grippo, Angela J.; Johnson, Alan Kim

2008-01-01

103

Effects of environmental exposures on the cardiovascular system: prenatal period through adolescence.  

PubMed

Exposures to drugs, chemical and biological agents, therapeutic radiation, and other factors before and after birth can lead to pediatric or adult cardiovascular anomalies. Furthermore, nutritional deficiencies in the perinatal period can cause cardiovascular anomalies. These anomalies may affect heart structure, the conduction system, the myocardium, blood pressure, or cholesterol metabolism. Developmental periods before and after birth are associated with different types of risks. The embryonic period is the critical window of vulnerability for congenital malformations. The fetal period seems to have lifelong effects on coronary heart disease and its precursors. During the weeks immediately after birth, susceptibility to myocardial damage seems to be high. Exposure to cancer chemotherapy or radiotherapy in childhood raises the risk of long-term progressive left ventricular dysfunction and other cardiovascular problems. In childhood and adolescence, use of recreational drugs such as cocaine and tobacco poses cardiovascular dangers as well. Where evidence about environmental exposures is limited, we have included models of disease and other exposures that are suggestive of the potential impact of environmental exposures. PMID:15060200

Mone, Suzanne M; Gillman, Matthew W; Miller, Tracie L; Herman, Eugene H; Lipshultz, Steven E

2004-04-01

104

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.

Roytvarf, Alexander; Shusterman, Vladimir

2008-01-01

105

Differential protection against oxidative stress and nitric oxide overproduction in cardiovascular and pulmonary systems by propofol during endotoxemia  

Microsoft Academic Search

BACKGROUND: Both overproduction of nitric oxide (NO) and oxidative injury of cardiovascular and pulmonary systems contribute to fatal cardiovascular depression during endotoxemia. We investigated in the present study the relative contribution of oxidative stress and NO to cardiovascular depression during different stages of endotoxemia, and delineated their roles in cardiovascular protective effects of a commonly used anesthetic propofol during endotoxemia.

Yen-Chin Liu; Alice YW Chang; Yu-Chuan Tsai; Julie YH Chan

2009-01-01

106

Temporal association between pulmonary and systemic effects of particulate matter in healthy and cardiovascular compromised rats.  

PubMed

Exposure to particulate matter (PM) has been associated with increased morbidity and mortality among individuals with cardiovascular disease. It is hypothesized that systemic alterations occur concurrent to pulmonary injury/inflammation, and contribute to cardiac events in compromised hosts. We explored this hypothesis using a rat model for human hypertension and cardiovascular disease (spontaneously hypertensive, SH), and normotensive Wistar Kyoto (WKY) rats. SH and WKY rats (12-13 wk old) were exposed either intratracheally (IT; 0.0, 1.0, or 5.0 mg/kg in saline) or nose-only (15 mg/m(3) x 6 h/d x 3 d/wk x 1, 2 or 4 wk) to combustion source residual oil fly ash (ROFA) with low metal content, and examined 1, 2 or 4 d later. Bronchoalveolar lavage fluid (BALF) albumin and neutrophils increased (SH approximately equal WKY) at d 1 following ROFA IT. With inhalation exposure, both strains experienced progressive histological lung damage and increases in BALF albumin and neutrophils during 1 to 4 wk (SH > WKY). Acute lung injury from ROFA IT was temporally associated with increases in plasma fibrinogen in both strains, but only the SH rats responded to the acute 1-wk ROFA inhalation. Longer term (2 or 4 wk) ROFA caused progressive lung injury (SH > WKY), but did not sustain the increase in fibrinogen. BALF glutathione increased in a temporal fashion similar to fibrinogen; however, only WKY rats demonstrated this response. There was a small but consistent decrease in blood lymphocytes and an increase in blood neutrophils in SH rats exposed to ROFA acutely. In conclusion, acute PM exposure can provoke an acute systemic thrombogenic response associated with pulmonary injury/inflammation and oxidative stress in cardiovascular compromised rats. This evidence is consistent with greater cardiovascular events during acute PM episodes in compromised humans. PMID:12396868

Kodavanti, Urmila P; Schladweiler, Mette C; Ledbetter, Allen D; Hauser, Russ; Christiani, David C; McGee, John; Richards, Judy R; Costa, Daniel L

2002-10-25

107

Transgenic animal models: new avenues in cardiovascular physiology  

Microsoft Academic Search

Application of molecular genetic tools to inherited cardiovascular disorders has provided important insights into the molecular\\u000a mechanisms underlying cardiomyopathies, arrhythmias, blood pressure regulation, and atherosclerosis. In addition, alteration\\u000a of gene expression has been observed under common cardiovascular conditions such as cardiac hypertrophy and heart failure.\\u000a Recent advances in transgenic and gene-targeting approaches allow a sophisticated manipulation of the mouse genome

W.-M. Franz; O. J. Mueller; R. Hartong; N. Frey; H. A. Katus

1997-01-01

108

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.

Pinheiro, Eduardo; Postolache, Octavian; Girao, Pedro

2010-01-01

109

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 NewtonÃÂs 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

110

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

111

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

Microsoft Academic Search

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

Johanna Gustafsson; Iva Gunnarsson; Ola Börjesson; Susanne Pettersson; Sonia Möller; Guo-Zhong Fei; Kerstin Elvin; Julia F Simard; Lars-Olof Hansson; Ingrid E Lundberg; Anders Larsson; Elisabet Svenungsson

2009-01-01

112

The Utility of Animal Models in Understanding Links between Psychosocial Processes and Cardiovascular Health  

PubMed Central

A bidirectional association between mood disorders and cardiovascular disease has been described; however, the neurobiological mechanisms that underlie this link have not been fully elucidated. The purpose of this review is first to describe some of the important behavioral neurobiological processes that are common to both mood and cardiovascular disorders. Second, this review focuses on the value of conducting research with animal models (primarily rodents) to investigate potential behavioral, physiological, and neural processes involved in the association of mood disorders and cardiovascular disease. In combination with findings from human research, the study of mechanisms underlying mood and cardiovascular regulation using animal models will enhance our understanding of the association of depression and cardiovascular disease, and can promote the development of novel interventions for individuals with these comorbid conditions.

Grippo, Angela J.

2011-01-01

113

The Utility of Animal Models in Understanding Links between Psychosocial Processes and Cardiovascular Health.  

PubMed

A bidirectional association between mood disorders and cardiovascular disease has been described; however, the neurobiological mechanisms that underlie this link have not been fully elucidated. The purpose of this review is first to describe some of the important behavioral neurobiological processes that are common to both mood and cardiovascular disorders. Second, this review focuses on the value of conducting research with animal models (primarily rodents) to investigate potential behavioral, physiological, and neural processes involved in the association of mood disorders and cardiovascular disease. In combination with findings from human research, the study of mechanisms underlying mood and cardiovascular regulation using animal models will enhance our understanding of the association of depression and cardiovascular disease, and can promote the development of novel interventions for individuals with these comorbid conditions. PMID:21949540

Grippo, Angela J

2011-04-01

114

Peroxisome proliferator-activated receptors in the cardiovascular system  

PubMed Central

Peroxisome proliferator-activated receptor (PPAR)s are a family of three nuclear hormone receptors, PPAR?, -?, and -?, which are members of the steriod receptor superfamily. The first member of the family (PPAR?) was originally discovered as the mediator by which a number of xenobiotic drugs cause peroxisome proliferation in the liver. Defined functions for all these receptors, until recently, mainly concerned their ability to regulate energy balance, with PPAR? being involved in ?-oxidation pathways, and PPAR? in the differentiation of adipocytes. Little is known about the functions of PPAR?, though it is the most ubiquitously expressed. Since their discovery, PPARs have been shown to be expressed in monocytes/macrophages, the heart, vascular smooth muscle cells, endothelial cells, and in atherosclerotic lesions. Furthermore, PPARs can be activated by a vast number of compounds including synthetic drugs, of the clofibrate, and anti-diabetic thiazoldinedione classes, polyunsaturated fatty acids, and a number of eicosanoids, including prostaglandins, lipoxygenase products, and oxidized low density lipoprotein. This review will aim to introduce the field of PPAR nuclear hormone receptors, and discuss the discovery and actions of PPARs in the cardiovascular system, as well as the source of potential ligands.

Bishop-Bailey, David

2000-01-01

115

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

116

Metal ions affecting the pulmonary and cardiovascular systems.  

PubMed

Some metals, such as copper and manganese, are essential to life and play irreplaceable roles in, e.g., the functioning of important enzyme systems. Other metals are xenobiotics, i.e., they have no useful role in human physiology and, even worse, as in the case of lead, may be toxic even at trace levels of exposure. Even those metals that are essential, however, have the potential to turn harmful at very high levels of exposure, a reflection of a very basic tenet of toxicology--"the dose makes the poison." Toxic metal exposure may lead to serious risks to human health. As a result of the extensive use of toxic metals and their compounds in industry and consumer products, these agents have been widely disseminated in the environment. Because metals are not biodegradable, they can persist in the environment and produce a variety of adverse effects. Exposure to metals can lead to damage in a variety of organ systems and, in some cases, metals also have the potential to be carcinogenic. Even though the importance of metals as environmental health hazards is now widely appreciated, the specific mechanisms by which metals produce their adverse effects have yet to be fully elucidated. The unifying factor in determining toxicity and carcinogenicity for most metals is the generation of reactive oxygen and nitrogen species. Metal-mediated formation of free radicals causes various modifications to nucleic acids, enhanced lipid peroxidation, and altered calcium and sulfhydryl homeostasis. Whilst copper, chromium, and cobalt undergo redox-cycling reactions, for metals such as cadmium and nickel the primary route for their toxicity is depletion of glutathione and bonding to sulfhydryl groups of proteins. This chapter attempts to show that the toxic effects of different metallic compounds may be manifested in the pulmonary and cardiovascular systems. The knowledge of health effects due to metal exposure is necessary for practising physicians, and should be assessed by inquiring about present and past occupational history and environmental exposure. PMID:21473377

Corradi, Massimo; Mutti, Antonio

2011-01-01

117

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

118

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

119

FoxO proteins: cunning concepts and considerations for the cardiovascular system  

PubMed Central

Dysfunction in the cardiovascular system can lead to the progression of a number of disease entities that can involve cancer, diabetes, cardiac ischaemia, neurodegeneration and immune system dysfunction. In order for new therapeutic avenues to overcome some of the limitations of present clinical treatments for these disorders, future investigations must focus upon novel cellular processes that control cellular development, proliferation, metabolism and inflammation. In this respect, members of the mammalian forkhead transcription factors of the O class (FoxOs) have increasingly become recognized as important and exciting targets for disorders of the cardiovascular system. In the present review, we describe the role of these transcription factors in the cardiovascular system during processes that involve angiogenesis, cardiovascular development, hypertension, cellular metabolism, oxidative stress, stem cell proliferation, immune system regulation and cancer. Current knowledge of FoxO protein function combined with future studies should continue to lay the foundation for the successful translation of these transcription factors into novel and robust clinical therapies.

Maiese, Kenneth; Chong, Zhao Zhong; Shang, Yan Chen; Hou, Jinling

2009-01-01

120

Biochemistry, Physiology and Pathophysiology of NADPH Oxidases in the Cardiovascular System  

PubMed Central

The NADPH oxidase (Nox) enzymes are critical mediators of cardiovascular physiology and pathophysiology. These proteins are expressed in virtually all cardiovascular cells, and regulate such diverse functions as differentiation, proliferation, apoptosis, senescence, inflammatory responses and oxygen sensing. They target a number of important signaling molecules, including kinases, phosphatases, transcription factors, ion channels and proteins that regulate the cytoskeleton. Nox enzymes have been implicated in many different cardiovascular pathologies: atherosclerosis, hypertension, cardiac hypertrophy and remodeling, angiogenesis and collateral formation, stroke and heart failure. In this review, we discuss in detail the biochemistry of Nox enzymes expressed in the cardiovascular system (Nox1, 2, 4 and 5), their roles in cardiovascular cell biology, and their contributions to disease development.

Lassegue, Bernard; San Martin, Alejandra; Griendling, Kathy K.

2012-01-01

121

Introduction: Cardiovascular physics.  

PubMed

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. PMID:17411258

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

2007-03-01

122

Invited review-computed tomographic angiography (cta) of the thoracic cardiovascular system in companion animals.  

PubMed

Computed tomographic angiography (CTA) of the thoracic cardiovascular system is offering new diagnostic opportunities in companion animal patients with the increasing availability of multidetector-row computed tomographic (MDCT) units in veterinary facilities. Optimal investigation of the systemic, pulmonary, and coronary circulation provides unique challenges due to the constant movement of the heart, the small size of several of the structures of interest, and the dependence of angiographic quality on various contrast bolus design and patient factors. Technical and practical aspects of thoracic cardiovascular CTA are reviewed in light of the currently available veterinary literature and future opportunities given utilizing MDCT in companion animal patients with suspected thoracic cardiovascular disease. PMID:24547874

Drees, Randi; François, Christopher J; Saunders, Jimmy H

2014-05-01

123

Role of the autonomic nervous system and baroreflex in stress-evoked cardiovascular responses in rats.  

PubMed

Abstract Restraint stress (RS) is an experimental model to study stress-related cardiovascular responses, characterized by sustained pressor and tachycardiac responses. We used pharmacologic and surgical procedures to investigate the role played by sympathetic nervous system (SNS) and parasympathetic nervous system (PSNS) in the mediation of stress-evoked cardiovascular responses. Ganglionic blockade with pentolinium significantly reduced RS-evoked pressor and tachycardiac responses. Intravenous treatment with homatropine methyl bromide did not affect the pressor response but increased tachycardia. Pretreatment with prazosin reduced the pressor and increased the tachycardiac response. Pretreatment with atenolol did not affect the pressor response but reduced tachycardia. The combined treatment with atenolol and prazosin reduced both pressor and tachycardiac responses. Adrenal demedullation reduced the pressor response without affecting tachycardia. Sinoaortic denervation increased pressor and tachycardiac responses. The results indicate that: (1) the RS-evoked cardiovascular response is mediated by the autonomic nervous system without an important involvement of humoral factors; (2) hypertension results primarily from sympathovascular and sympathoadrenal activation, without a significant involvement of the cardiac sympathetic component (CSNS); (3) the abrupt initial peak in the hypertensive response to restraint is sympathovascular-mediated, whereas the less intense but sustained hypertensive response observed throughout the remaining restraint session is mainly mediated by sympathoadrenal activation and epinephrine release; (4) tachycardia results from CSNS activation, and not from PSNS inhibition; (5) RS evokes simultaneous CSNS and PSNS activation, and heart rate changes are a vector of both influences; (6) the baroreflex is functional during restraint, and modulates both the vascular and cardiac responses to restraint. PMID:24903268

Dos Reis, Daniel Gustavo; Fortaleza, Eduardo Albino Trindade; Tavares, Rodrigo Fiacadori; Corrêa, Fernando Morgan Aguiar

2014-07-01

124

P2 receptor subtypes in the cardiovascular system.  

PubMed Central

Extracellular nucleotides have been implicated in a number of physiological functions. Nucleotides act on cell-surface receptors known as P2 receptors, of which several subtypes have been cloned. Both ATP and ADP are stored in platelets and are released upon platelet activation. Furthermore, nucleotides are also released from damaged or broken cells. Thus during vascular injury nucleotides play an important role in haemostasis through activation of platelets, modulation of vascular tone, recruitment of neutrophils and monocytes to the site of injury, and facilitation of adhesion of leucocytes to the endothelium. Nucleotides also moderate these functions by generating nitric oxide and prostaglandin I2 through activation of endothelial cells, and by activating different receptor subtypes on vascular smooth muscle cells. In the heart, P2 receptors regulate contractility through modulation of L-type Ca2+ channels, although the molecular mechanisms involved are still under investigation. Classical pharmacological studies have identified several P2 receptor subtypes in the cardiovascular system. Molecular pharmacological studies have clarified the nature of some of these receptors, but have complicated the picture with others. In platelets, the classical P2T receptor has now been resolved into three P2 receptor subtypes: the P2Y1, P2X1 and P2TAC receptors (the last of these, which is coupled to the inhibition of adenylate cyclase, is yet to be cloned). In peripheral blood leucocytes, endothelial cells, vascular smooth muscle cells and cardiomyocytes, the effects of classical P2X, P2Y and P2U receptors have been found to be mediated by more than one P2 receptor subtype. However, the exact functions of these multiple receptor subtypes remain to be understood, as P2-receptor-selective agonists and antagonists are still under development.

Kunapuli, S P; Daniel, J L

1998-01-01

125

Chronic Contamination of Rats with 137 Cesium Radionuclide: Impact on the Cardiovascular System  

Microsoft Academic Search

Cardiovascular system impairment has been observed in children and in liquidators exposed to the Chernobyl nuclear power plant\\u000a accident. No experimental studies of animals have analyzed whether these disorders might be attributed to chronic ingestion\\u000a of low levels of cesium 137 (137Cs). Biochemical, physiological, and molecular markers of the cardiovascular system were analyzed in rats exposed through\\u000a drinking water to

Yann Guéguen; Philippe Lestaevel; Line Grandcolas; Cédric Baudelin; Stéphane Grison; Jean-René Jourdain; Patrick Gourmelon; Maâmar Souidi

2008-01-01

126

Designing an outcome-oriented computer decision-support system for cardiovascular ICU—A preliminary report  

Microsoft Academic Search

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

Francis Lau; Daniel Vincent; Don Fenna; Randy Goebel; Dennis Modry

1991-01-01

127

Oxidative stress-mediated effects of angiotensin II in the cardiovascular system  

PubMed Central

Angiotensin II (Ang II), an endogenous peptide hormone, plays critical roles in the pathophysiological modulation of cardiovascular functions. Ang II is the principle effector of the renin-angiotensin system for maintaining homeostasis in the cardiovascular system, as well as a potent stimulator of NAD(P)H oxidase, which is the major source and primary trigger for reactive oxygen species (ROS) generation in various tissues. Recent accumulating evidence has demonstrated the importance of oxidative stress in Ang II-induced heart diseases. Here, we review the recent progress in the study on oxidative stress-mediated effects of Ang II in the cardiovascular system. In particular, the involvement of Ang II-induced ROS generation in arrhythmias, cell death/heart failure, ischemia/reperfusion injury, cardiac hypertrophy and hypertension are discussed. Ca2+/calmodulin-dependent protein kinase II is an important molecule linking Ang II, ROS and cardiovascular pathological conditions.

Wen, Hairuo; Gwathmey, Judith K; Xie, Lai-Hua

2014-01-01

128

Angiotensin II type-2 receptor-specific effects on the cardiovascular system  

PubMed Central

The renin-angiotensin system (RAS) is intricately involved in cardiovascular homeostasis. It is well known that angiotensin II, the key effector in RAS, contributes to a range of cardiovascular pathologies and diseases via angiotensin II type-1 receptor (AT1R) activation. However, the role of angiotensin II type-2 receptor (AT2R) regulation is less well understood. Recent studies describe the role of the AT2R on cardiovascular function in normal and pathologic conditions. The data describe an important role of AT2R in blood pressure regulation, cardiac hypertrophy and fibrosis, myocardial infarction and vascular homeostasis.

Li, Ying; Li, Xiao-hui

2012-01-01

129

Coronary and systemic hemodynamic effects of sildenafil citrate: from basic science to clinical studies in patients with cardiovascular disease  

Microsoft Academic Search

Sildenafil citrate is the first oral phosphodiesterase type 5 inhibitor approved for the treatment of erectile dysfunction. The wide use of sildenafil by patients with erectile dysfunction and cardiovascular disease has resulted in a considerable number of independent studies investigating the cardiovascular safety and functional role of the phosphodiesterase type 5-cyclic guanosine monophosphate–nitric oxide pathway in the cardiovascular system. Endothelial

Hunter C Gillies; David Roblin; Graham Jackson

2002-01-01

130

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

131

A system for real-time XMR guided cardiovascular intervention  

Microsoft Academic Search

The hybrid magnetic resonance (MR)\\/X-ray suite (XMR) is a recently introduced imaging solution that provides new possibilities for guidance of cardiovascular catheterization procedures. We have previously described and validated a tech- nique based on optical tracking to register MR and X-ray images obtained from the sliding table XMR configuration. The aim of our recent work was to extend our technique

Kawal S. Rhode; Maxime Sermesant; David C. Brogan; Sanjeet Hegde; John H. Hipwell; Pier Lambiase; Eric Rosenthal; Clifford Bucknall; Shakeel A. Qureshi; Jaswinder S. Gill; Reza Razavi; Derek L. G. Hill

2005-01-01

132

A computable cellular stress network model for non-diseased pulmonary and cardiovascular tissue  

PubMed Central

Background Humans and other organisms are equipped with a set of responses that can prevent damage from exposure to a multitude of endogenous and environmental stressors. If these stress responses are overwhelmed, this can result in pathogenesis of diseases, which is reflected by an increased development of, e.g., pulmonary and cardiac diseases in humans exposed to chronic levels of environmental stress, including inhaled cigarette smoke (CS). Systems biology data sets (e.g., transcriptomics, phosphoproteomics, metabolomics) could enable comprehensive investigation of the biological impact of these stressors. However, detailed mechanistic networks are needed to determine which specific pathways are activated in response to different stressors and to drive the qualitative and eventually quantitative assessment of these data. A current limiting step in this process is the availability of detailed mechanistic networks that can be used as an analytical substrate. Results We have built a detailed network model that captures the biology underlying the physiological cellular response to endogenous and exogenous stressors in non-diseased mammalian pulmonary and cardiovascular cells. The contents of the network model reflect several diverse areas of signaling, including oxidative stress, hypoxia, shear stress, endoplasmic reticulum stress, and xenobiotic stress, that are elicited in response to common pulmonary and cardiovascular stressors. We then tested the ability of the network model to identify the mechanisms that are activated in response to CS, a broad inducer of cellular stress. Using transcriptomic data from the lungs of mice exposed to CS, the network model identified a robust increase in the oxidative stress response, largely mediated by the anti-oxidant NRF2 pathways, consistent with previous reports on the impact of CS exposure in the mammalian lung. Conclusions The results presented here describe the construction of a cellular stress network model and its application towards the analysis of environmental stress using transcriptomic data. The proof-of-principle analysis described here, coupled with the future development of additional network models covering distinct areas of biology, will help to further clarify the integrated biological responses elicited by complex environmental stressors such as CS, in pulmonary and cardiovascular cells.

2011-01-01

133

Thiazolidinediones: effects on insulin resistance and the cardiovascular system  

PubMed Central

Thiazolidinediones (TZDs) have been used for the treatment of hyperglycaemia in type 2 diabetes for the past 10 years. They may delay the development of type 2 diabetes in individuals at high risk of developing the condition, and have been shown to have potentially beneficial effects on cardiovascular risk factors. TZDs act as agonists of peroxisome proliferator-activated receptor-? (PPAR-?) primarily in adipose tissue. PPAR-? receptor activation by TZDs improves insulin sensitivity by promoting fatty acid uptake into adipose tissue, increasing production of adiponectin and reducing levels of inflammatory mediators such as tumour necrosis factor-alpha (TNF-?), plasminogen activator inhibitor-1(PAI-1) and interleukin-6 (IL-6). Clinically, TZDs have been shown to reduce measures of atherosclerosis such as carotid intima-media thickness (CIMT). However, in spite of beneficial effects on markers of cardiovascular risk, TZDs have not been definitively shown to reduce cardiovascular events in patients, and the safety of rosiglitazone in this respect has recently been called into question. Dual PPAR-?/? agonists may offer superior treatment of insulin resistance and cardioprotection, but their safety has not yet been assured.

Quinn, C E; Hamilton, P K; Lockhart, C J; McVeigh, G E

2007-01-01

134

Computational modelling and evaluation of cardiovascular response under pulsatile impeller pump support  

PubMed Central

This study presents a numerical simulation of cardiovascular response in the heart failure condition under the support of a Berlin Heart INCOR impeller pump-type ventricular assist device (VAD). The model is implemented using the CellML modelling language. To investigate the potential of using the Berlin Heart INCOR impeller pump to produce physiologically meaningful arterial pulse pressure within the various physiological constraints, a series of VAD-assisted cardiovascular cases are studied, in which the pulsation ratio and the phase shift of the VAD motion profile are systematically changed to observe the cardiovascular responses in each of the studied cases. An optimization process is proposed, including the introduction of a cost function to balance the importance of the characteristic cardiovascular variables. Based on this cost function it is found that a pulsation ratio of 0.35 combined with a phase shift of 200° produces the optimal cardiovascular response, giving rise to a maximal arterial pulse pressure of 12.6 mm Hg without inducing regurgitant pump flow while keeping other characteristic cardiovascular variables within appropriate physiological ranges.

Shi, Yubing; Brown, Alistair G.; Lawford, Patricia V.; Arndt, Andreas; Nuesser, Peter; Hose, D. Rodney

2011-01-01

135

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

136

Adrenoreceptors and nitric oxide in the cardiovascular system  

PubMed Central

Nitric Oxide (NO) is a small molecule that continues to attract much attention from the scientific community. Since its discovery, it has been evident that NO has a crucial role in the modulation of vascular tone. Moreover, NO is involved in multiple signal transduction pathways thus contributing to the regulation of many cellular functions. NO effects can be either dependent or independent on cGMP, and rely also upon several mechanisms such as the amount of NO, the compartmentalization of the enzymes responsible for its biosynthesis (NOS), and the local redox conditions. Several evidences highlighted the correlation among adrenoreceptors activity, vascular redox status and NO bioavailability. It was suggested a possible crosstalk between NO and oxidative stress hallmarks in the endothelium function and adaptation, and in sympathetic vasoconstriction control. Adrenergic vasoconstriction is a balance between a direct vasoconstrictive effect on smooth muscle and an indirect vasorelaxant action caused by ?2- and ?-adrenergic endothelial receptor-triggered NO release. An increased oxidative stress and a reduction of NO bioavailability shifts this equilibrium causing the enhanced vascular adrenergic responsiveness observed in hypertension. The activity of NOS contributes to manage the adrenergic pathway, thus supporting the idea that the endothelium might control or facilitate ?-adrenergic effects on the vessels and the polymorphic variants in ?2-receptors and NOS isoforms could influence aging, some pathological conditions and individual responses to drugs. This seems to be dependent, almost in part, on differences in the control of vascular tone exerted by NO. Given its involvement in such important mechanisms, the NO pathway is implicated in aging process and in both cardiovascular and non-cardiovascular conditions. Thus, it is essential to pinpoint NO involvement in the regulation of vascular tone for the effective clinical/therapeutic management of cardiovascular diseases (CVD).

Conti, Valeria; Russomanno, Giusy; Corbi, Graziamaria; Izzo, Viviana; Vecchione, Carmine; Filippelli, Amelia

2013-01-01

137

Synchronization between main rhythmic processes in the human cardiovascular system.  

PubMed

For the cases of spontaneous respiration and paced respiration with a fixed frequency and linearly increasing frequency, we investigate synchronization between three main rhythmic processes governing the cardiovascular dynamics in humans, namely, the main heart rhythm, respiration, and the process whose fundamental frequency is close to 0.1 Hz. The analysis of the experimental records reveals synchronous regimes of different orders n:m between all the three main rhythms. The influence of the regime of breathing and the magnitude of heart rate variability on the degree of synchronization is considered. PMID:14682979

Prokhorov, M D; Ponomarenko, V I; Gridnev, V I; Bodrov, M B; Bespyatov, A B

2003-10-01

138

Desensitization of G-protein-coupled receptors in the cardiovascular system.  

PubMed

Multiple mechanisms exist to control the signaling and density of G-protein-coupled receptors (GPRs). Upon agonist binding and receptor activation, a series of reactions participate in the turn off or desensitization of GPRs. Many GPRs are phosphorylated by protein kinases and consequently uncoupled from G proteins. In addition, many GPRs are sequestered from the cell surface and become inaccessible to their activating ligands. Both receptor:G protein uncoupling and receptor sequestration may involve the participation of arrestins or other proteins. A model for receptor regulation has been developed from studies of the beta-adrenergic receptor. However, recent studies suggest that other GPRs important in the cardiovascular system, such as the muscarinic cholinergic receptors that regulate heart rate, might be regulated by mechanisms other than those that regulate the beta-adrenergic receptors. This review summarizes our current understanding of the processes involved in the desensitization of GPRs. PMID:10099686

Bünemann, M; Lee, K B; Pals-Rylaarsdam, R; Roseberry, A G; Hosey, M M

1999-01-01

139

Imbalance between Endothelial Damage and Repair: A Gateway to Cardiovascular Disease in Systemic Lupus Erythematosus  

PubMed Central

Atherosclerosis is accelerated in patients with systemic lupus erythematosus (SLE) and it leads to excessive cardiovascular complications in these patients. Despite the improved awareness of cardiovascular disease and advent of clinical diagnostics, the process of atherogenesis in most patients remains clinically silent until symptoms and signs of cardiovascular complications develop. As evidence has demonstrated that vascular damage is already occurring before clinically overt cardiovascular disease develops in lupus patients, intervention at the preclinical stage of atherogenesis would be plausible. Indeed, endothelial dysfunction, one of the earliest steps of atherogenesis, has been demonstrated to occur in lupus patients even when they are naïve for cardiovascular disease. Currently known “endothelium-toxic” factors including type 1 interferon, proinflammatory cytokines, inflammatory cells, immune complexes, costimulatory molecules, neutrophils extracellular traps, lupus-related autoantibodies, oxidative stress, and dyslipidemia, coupled with the aberrant functions of the endothelial progenitor cells (EPC) which are crucial to vascular repair, likely tip the balance towards endothelial dysfunction and propensity to develop cardiovascular disease in lupus patients. In this review, altered physiology of the endothelium, factors leading to perturbed vascular repair contributed by lupus EPC and the impact of proatherogenic factors on the endothelium which potentially lead to atherosclerosis in lupus patients will be discussed.

2014-01-01

140

Beta 3-adrenoreceptor Regulation of Nitric Oxide in the Cardiovascular System  

PubMed Central

The presence of a third ?-adrenergic receptor (?3-AR) in the cardiovascular system has challenged the classical paradigm of sympathetic regulation by ?1- and ?2-adrenergic receptors. While ?3-AR’s role in the cardiovascular system remains controversial, increasing evidence suggests that it serves as a “brake” in sympathetic overstimulation - it is activated at high catecholamine concentrations, producing a negative inotropic effect that antagonizes ?1-and ?2-AR activity. The anti-adrenergic effects induced by ?3-AR were initially linked to nitric oxide (NO) release via endothelial NO synthase (eNOS), although more recently it has been shown under some conditions to increase NO production in the cardiovascular system via the other two NOS isoforms, namely inducible NOS (iNOS) and neuronal NOS (nNOS). We summarize recent findings regarding ?3-AR effects on the cardiovascular system and explore its prospective as a therapeutic target, particularly focusing on its emerging role as an important mediator of NO signaling in the pathogenesis of cardiovascular disorders.

Moens, An L.; Yang, Ronghua; Watts, Vabren L.; Barouch, Lili A.

2010-01-01

141

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

142

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

143

Mechanisms underlying altered mood and cardiovascular dysfunction: the value of neurobiological and behavioral research with animal models  

PubMed Central

A bidirectional association between mood disorders and cardiovascular diseases has been described in humans, yet the precise neurobiological mechanisms that underlie this association are not fully understood. This article is focused on neurobiological processes and mediators in mood and cardiovascular disorders, with an emphasis on common mechanisms including stressor reactivity, neuroendocrine and neurohumoral changes, immune alterations, autonomic and cardiovascular dysregulation, and central neurotransmitter and neuropeptide dysfunction. A discussion of the utility of experimental investigations with rodent models, including those in rats and prairie voles (Microtus ochrogaster), is presented. Specific studies using these models are reviewed, focusing on the analysis of behavioral, physiological and neural mechanisms underlying depressive disorders and cardiovascular disease. Considered in combination with studies using human samples, the investigation of mechanisms underlying depressive behaviors and cardiovascular regulation using animal models will enhance our understanding of the association of depression and cardiovascular disease, and will promote the development of improved interventions for individuals with these detrimental disorders.

Grippo, Angela J.

2008-01-01

144

Mechanisms underlying altered mood and cardiovascular dysfunction: the value of neurobiological and behavioral research with animal models.  

PubMed

A bidirectional association between mood disorders and cardiovascular diseases has been described in humans, yet the precise neurobiological mechanisms that underlie this association are not fully understood. This article is focused on neurobiological processes and mediators in mood and cardiovascular disorders, with an emphasis on common mechanisms including stressor reactivity, neuroendocrine and neurohumoral changes, immune alterations, autonomic and cardiovascular dysregulation, and central neurotransmitter and neuropeptide dysfunction. A discussion of the utility of experimental investigations with rodent models, including those in rats and prairie voles (Microtus ochrogaster), is presented. Specific studies using these models are reviewed, focusing on the analysis of behavioral, physiological and neural mechanisms underlying depressive disorders and cardiovascular disease. Considered in combination with studies using human samples, the investigation of mechanisms underlying depressive behaviors and cardiovascular regulation using animal models will enhance our understanding of the association of depression and cardiovascular disease, and will promote the development of improved interventions for individuals with these detrimental disorders. PMID:18703084

Grippo, Angela J

2009-02-01

145

Measurement Error Case Series Models with Application to Infection-Cardiovascular Risk in OlderPatients on Dialysis.  

PubMed

Infection and cardiovascular disease are leading causes of hospitalization and death in older patients on dialysis. Our recent work found an increase in the relative incidence of cardiovascular outcomes during the ~ 30 days after infection-related hospitalizations using the case series model, which adjusts for measured and unmeasured baseline confounders. However, a major challenge in modeling/assessing the infection-cardiovascular risk hypothesis is that the exact time of infection, or more generally "exposure," onsets cannot be ascertained based on hospitalization data. Only imprecise markers of the timing of infection onsets are available. Although there is a large literature on measurement error in the predictors in regression modeling, to date there is no work on measurement error on the timing of a time-varying exposure to our knowledge. Thus, we propose a new method, the measurement error case series (MECS) models, to account for measurement error in time-varying exposure onsets. We characterized the general nature of bias resulting from estimation that ignores measurement error and proposed a bias-corrected estimation for the MECS models. We examined in detail the accuracy of the proposed method to estimate the relative incidence. Hospitalization data from United States Renal Data System, which captures nearly all (> 99%) patients with end-stage renal disease in the U.S. over time, is used to illustrate the proposed method. The results suggest that the estimate of the cardiovascular incidence following the 30 days after infections, a period where acute effects of infection on vascular endothelium may be most pronounced, is substantially attenuated in the presence of infection onset measurement error. PMID:23650442

Mohammed, Sandra M; Sentürk, Damla; Dalrymple, Lorien S; Nguyen, Danh V

2012-12-01

146

Implementation of a computerized cardiovascular information system in a private hospital setting  

Microsoft Academic Search

Background The use of clinical databases improves quality of care, reduces operating costs, helps secure managed care contracts, and assists in clinical research. Because of the large physician input required to maintain these systems, private institutions have often found them difficult to implement. At LDS Hospital in Salt Lake City, Utah, we developed a cardiovascular information system (LDS-CIS) patterned after

Gregory S. Taylor; Joseph B. Muhlestein; Galen S. Wagner; Tami L. Bair; Patty Li; Jeffrey L. Anderson

1998-01-01

147

The role of nitric oxide in regulation of the cardiovascular system in reptiles  

Microsoft Academic Search

The roles that nitric oxide (NO) plays in the cardiovascular system of reptiles are reviewed, with particular emphasis on its effects on central vascular blood flows in the systemic and pulmonary circulations. New data is presented that describes the effects on hemodynamic variables in varanid lizards of exogenously administered NO via the nitric oxide donor sodium nitroprusside (SNP) and inhibition

Nini Skovgaard; Gina Galli; Augusto Abe; Edwin W. Taylor; Tobias Wang

2005-01-01

148

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

2011-02-01

149

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

PubMed Central

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.

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.

2012-01-01

150

Pharmacokinetic and pharmacodynamic modeling of the antiplatelet and cardiovascular effects of cilostazol in healthy humans  

Microsoft Academic Search

Objective: Cilostazol is an antiplatelet agent with vasodilating properties. It has been used to treat patients with peripheral ischemia, such as intermittent claudication. We used a pharmacokinetic-pharmacodynamic model to analyze the relation between the plasma concentration of cilostazol, the inhibitory effect of the drug onplatelet aggregation, and the cardiovascular effects of the drug on healthy humans.Methods: A single oral dose

Su Kyung Woo; Won Ku Kang; Kwang-il Kwon

2002-01-01

151

Matching index of refraction using a diethyl phthalate\\/ethanol solution for in vitro cardiovascular models  

Microsoft Academic Search

Experiments studying cardiovascular geometries require a working fluid that matches the high index of refraction of glass and silicone, has a low viscosity, and is safe and inexpensive. A good candidate working fluid is diethyl phthalate (DEP), diluted with ethanol. Measurements were made of index of refraction and viscosity of varied dilutions at a range of temperatures, and empirical models

P. Miller; K. Danielson; G. Moody; A. Slifka; E. Drexler; J. Hertzberg

2006-01-01

152

Salud Para Su Corazón: A Community-Based Latino Cardiovascular Disease Prevention and Outreach Model  

Microsoft Academic Search

Cardiovascular disease (CVD) is the leading cause of death for Latinos living in the United States. This population is generally unaware of important lifestyle or behavioral changes that can prevent CVD. The National Heart, Lung, and Blood Institute (NHLBI) designed and implemented Salud para su Corazón (Health for Your Heart), a culturally appropriate, community-based, theory-driven intervention model. NHLBI's goals were:

Rina Alcalay; Matilde Alvarado; Hector Balcazar; Eileen Newman; Elmer Huerta

1999-01-01

153

[Implementing cardiovascular prevention in the real world: presentation of an integrated hospital-field model].  

PubMed

Numerous studies have documented that cardiovascular prevention in subjects at high risk has a large impact on the clinical outcomes. Data also show the efficacy of an early, intensive, well-structured, professionally expert, multidisciplinary intervention, making use of adequate behavioural and pharmacologic instruments, on the global risk. Such intervention is, however, available at present for very few healthcare users, while the majority, above all in primary prevention, receive a programme of low impact, with poor feedback between the hospital specialist and general practitioner (GP), and often limited to the simple prescription of treatment or to specialist check-ups and/or general advice on lifestyle. The project of implementation takes as its starting point this analysis and the premise that for an intervention of cardiovascular prevention to be effective, particularly in the long term, and really applicable to the broad population, it must be governed primarily by the GP--providing that s/he be adequately trained, utilize new and more dynamic caring modes, and be able to count concretely both on integration with the specialist and on the support of a multidisciplinary team for specific interventions. The paper presents the various stages of the project: from definition of the resources available (health district, GPs, hospital specialists) to the need for GP training, to the modes of operation: instruments for risk calculation, procedures followed, model of integration between GP and specialist, identification of the goals and indicators. This is a low cost project in terms of both the human and structural resources employed, utilizing what is already available in the healthcare system of our country. One of its most original aspects is the medical visit jointly conducted by the GP and hospital specialist, which realizes in concrete terms the integration of the skills: GPs can finally confront in the field the specialist of referral, acquire new skills, improve their daily mode of operating, while they will be gratified by a work more in line with their professional image, and become promoters of health. Finally, this project highlights the propositive and operative role assumed by cardiac rehabilitation and prevention, which, after developing over the years a specific know-how on the subject, now transmits these skills to other healthcare resources and creates a link with the local territory, so providing an appropriate response to the need to put into practice primary and secondary cardiovascular prevention. PMID:12918169

Griffo, Raffaele; Blondett, Massimo; Stellini, Fabio; Camerini, Alberto; Picciotto, Rinaldo

2003-06-01

154

Depressive and cardiovascular disease comorbidity in a rat model of social stress: a putative role for corticotropin-releasing factor  

PubMed Central

Rationale Depression is associated with medical comorbidities, particularly cardiovascular disease. However, mechanisms linking depression and cardiovascular disease remain unclear. Objectives This study investigated whether the rat resident–intruder model of social stress would elicit behavioral dysfunctions and autonomic changes characteristic of psychiatric/cardiovascular comorbidity. Furthermore, the efficacy of the corticotropin-releasing factor-1 (CRF1) receptor antagonist, NBI-30775 (NBI), or the tricyclic antidepressant, desipramine (DMI), to prevent social stress-induced behavioral, neuroendocrine, and cardiovascular changes were evaluated. Methods Adult male rats were exposed to resident–intruder stress (seven consecutive days) and systemically administered NBI (10 mg/kg/7 days), DMI (10 mg/kg/14 days), or vehicle. The efficacy of NBI and DMI to alter the behavioral and neuroendocrine responses to social stress was assessed. Furthermore, their effects on stress-induced forced swim behavior (FST), bladder and adrenal weight, and heart rate variability (HRV) were examined. Results NBI, but not DMI, increased time spent in an upright, defensive posture and the latency to submit to the resident. Additionally, only NBI reduced social stress-induced adrenocorticotropic hormone and corticosterone release. Social stress increased FST immobility, caused bladder and adrenal hypertrophy, and decreased HRV. Both NBI and DMI blocked stress-induced increases in immobility during the FST. However, only NBI inhibited social stress-induced adrenal and bladder hypertrophy and decreases in heart rate variability. Conclusions Rat resident–intruder stress paradigm models aspects of psychiatric/medical comorbidity. Furthermore, the CRF system may contribute to both the behavioral response during social stress and its behavioral and autonomic consequences, offering insight into potential therapy to treat these comorbid conditions.

McFadden, Kile V.; Grigoriadis, Dimitri; Bhatnagar, Seema; Valentino, Rita J.

2013-01-01

155

Health system challenges of cardiovascular disease and diabetes in four Eastern Mediterranean countries.  

PubMed

This paper presents evidence from research into health system challenges of cardiovascular disease (CVD) and diabetes in four Eastern Mediterranean countries: the occupied Palestinian territory, Syria, Tunisia and Turkey. We address two questions. How has the health system in each country been conceptualised and organised to manage the provision of care for those with CVD or diabetes? And what were key concerns about the institutional ability to address this challenge? Research took place from 2009 to 2010, shortly before the political upheavals in the region, and notably in Syria and Tunisia. Data collection involved a review of key documents, interviews with key informants and brief data collection in clinics. In analysing the data, we adopted the analytical schema proposed by Walt and Gilson, distinguishing content, actors, context and process. Key findings from each country highlighted concerns about fragmented provision and a lack of coordination. Specific concerns included: the lack of patient referral pathways, functioning health information systems and investment in staff. Regarding issues underlying these 'visible' problems in managing these diseases, we highlight implications of the wider systemic pressure for reform of health-sector finance in each country, based on neoliberal models. PMID:24004405

Phillimore, Peter; Zaman, Shahaduz; Ahmad, Balsam; Shoaibi, Azza; Khatib, Rasha; Khatib, Rana; Husseini, Abdullatif; Fouad, Fouad; Elias, Madonna; Maziak, Wasim; Tlili, Faten; Tinsa, Francine; Ben Romdhane, Habiba; K?l?ç, Bülent; Kalaça, Sibel; Ünal, Belgin; Critchley, Julia

2013-01-01

156

Proceedings of the Symposium Teaching Cardiovascular Physiology Outside the Lecture Hall.  

ERIC Educational Resources Information Center

Provided are 10 papers presented during a symposium on teaching cardiovascular physiology outside the lecture hall. Topics addressed include a mechanical model of the cardiovascular system for effective teaching, separate course for experiments in cardiovascular physiology, selective laboratory (alternative to cookbook experiments), cardiovascular

Michael, Joel A.; Rovick, Allen A., Eds.

1983-01-01

157

The Bold Promise Project: a system change in primary care to support cardiovascular risk screening in New Zealand  

Microsoft Academic Search

Methods Several system changes were developed within primary care practice management software to identify the patient cohort eligible for cardiovascular risk screening, to calculate cardiovascular disease risk (CVR), and to extract the data for reporting on screening outcomes and clinical management indicators in high risk patients. Following a baseline audit, the system changes were piloted over 12 months in three

Gary Sinclair; Andrew Kerr

158

Cardiovascular Risk in Chronic Kidney Disease: Role of the Sympathetic Nervous System  

PubMed Central

Patients with chronic kidney disease are at significantly increased risk for cardiovascular disease and sudden cardiac death. One mechanism underlying increased cardiovascular risk in patients with renal failure includes overactivation of the sympathetic nervous system (SNS). Multiple human and animal studies have shown that central sympathetic outflow is chronically elevated in patients with both end-stage renal disease (ESRD) and chronic kidney disease (CKD). SNS overactivation, in turn, increases the risk of cardiovascular disease and sudden death by increasing arterial blood pressure, arrythmogenicity, left ventricular hypertrophy, and coronary vasoconstriction and contributes to the progression renal disease. This paper will examine the evidence for SNS overactivation in renal failure from both human and experimental studies and discuss mechanisms of SNS overactivity in CKD and therapeutic implications.

Park, Jeanie

2012-01-01

159

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...

160

Influence of mitochondrion-toxic agents on the cardiovascular system.  

PubMed

Cardiovascular disease may be induced or worsened by mitochondrion-toxic agents. Mitochondrion-toxic agents may be classified as those with or without a clinical effect, those which induce cardiac disease only in humans or animals or both, as prescribed drugs, illicit drugs, exotoxins, or nutritiants, as those which affect the heart exclusively or also other organs, as those which are effective only in patients with a mitochondrial disorder or cardiac disease or also in healthy subjects, or as solid, liquid, or volatile agents. In humans, cardiotoxic agents due to mitochondrial dysfunction include anthracyclines (particularly doxorubicin), mitoxantrone, cyclophosphamide, cisplatin, fluorouracil, imatinib, bortezomib, trastuzumab, arsenic trioxide, cyclosporine-A, zidovudine, lamotrigine, glycosides, lidocain, isoproterenol, nitroprusside, pivalic acid, alcohol, cocaine, pesticides, cadmium, mycotoxins, cyanotoxins, meat meal, or carbon monoxide. Even more agents exhibit cardiac abnormalities due to mitochondrion-toxicity only in animals or tissue cultures. The mitochondrion-toxic effect results from impairment of the respiratory chain, the oxidative phosphorylation, the Krebs cycle, or the ?-oxidation, from decrease of the mitochondrion-membrane potential, from increased oxidative stress, reduced anti-oxidative capacity, or from induction of apoptosis. Cardiac abnormalities induced via these mechanisms include cardiomyopathy, myocarditis, coronary heart disease, arrhythmias, heart failure, or Takotsubo syndrome. Discontinuation of the cardiotoxic agent results in complete recovery in the majority of the cases. Antioxidants and nutritiants may be of additional help. Particularly coenzyme-Q, riboflavin, vitamin-E, vitamin-C, L-carnitine, vitamin-D, thiamin, folic acid, omega-3 fatty acids, and D-ribose may alleviate mitochondrial cardiotoxic effects. PMID:24036395

Finsterer, Josef; Ohnsorge, Peter

2013-12-01

161

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

162

Step response analyses of the cardiovascular system and their application to the measurement of systemic and pulmonary vein compliances  

Microsoft Academic Search

Summary A theoretical analysis of the step response in the closed cardiovascular system induced by a sudden shift of the right cardiac output curve predicted that if the relations of the right heart output (COr) and the total systemic capillary flow (CFs) to the systemic venous pressure (Psv) are linear, then the time course ofPsv change will become monexponential with

Akira Kamiya; Ken-ichi Yamakoshi; Masahiro Shibata; Atsushi Kawarada; Hideaki Shimazu

1986-01-01

163

System-level multi-target drug discovery from natural products with applications to cardiovascular diseases.  

PubMed

The term systems pharmacology describes a field of study that uses computational and experimental approaches to broaden the view of drug actions rooted in molecular interactions and advance the process of drug discovery. The aim of this work is to stick out the role that the systems pharmacology plays across the multi-target drug discovery from natural products for cardiovascular diseases (CVDs). Firstly, based on network pharmacology methods, we reconstructed the drug-target and target-target networks to determine the putative protein target set of multi-target drugs for CVDs treatment. Secondly, we reintegrated a compound dataset of natural products and then obtained a multi-target compounds subset by virtual-screening process. Thirdly, a drug-likeness evaluation was applied to find the ADME-favorable compounds in this subset. Finally, we conducted in vitro experiments to evaluate the reliability of the selected chemicals and targets. We found that four of the five randomly selected natural molecules can effectively act on the target set for CVDs, indicating the reasonability of our systems-based method. This strategy may serve as a new model for multi-target drug discovery of complex diseases. PMID:24792224

Zheng, Chunli; Wang, Jinan; Liu, Jianling; Pei, Mengjie; Huang, Chao; Wang, Yonghua

2014-08-01

164

Comparison between recombinant baculo- and adenoviral-vectors as transfer system in cardiovascular cells.  

PubMed

The development of effective gene-therapeutic applications for cardiovascular disorders is in part limited by the lack of appropriate delivery systems. In an attempt to overcome this deficiency, we investigated the ability of baculoviral vectors to transduce human cardiovascular cells, for which data are missing in literature. Additionally, baculovirus ability to transduce target cells was compared to that of an adenoviral vector, a well characterized and widely used viral vector. Transduction experiments, performed using baculo/adenoviral vectors expressing the enhanced green fluorescence protein, revealed that, under the experimental condition considered, baculoviruses but not adenoviruses efficiently transduce human coronary smooth muscle cells (hCSMC); an opposite behavior was noticed for human coronary endothelial cells (hCEC). Thus, baculoviral vectors are potentially indicated as transfer system in the treatment of coronary restenosis, where growth inhibitory genes should reach hCSMC but not hCEC. When used to transduce human cardiomyocytes and fibroblasts, both vectors behaved similarly. Finally, studies on cellular DNA replication revealed a more prolonged and pronounced negative effect on cells transduced by adenoviral compared to baculoviral vectors. Our data indicate that baculoviruses represent an attractive alternative to adenoviruses as transfer vectors in cardiovascular cells and that baculovirus have the potential to be used as gene transfer system in cardiovascular diseases such as restenosis. PMID:16195789

Grassi, G; Köhn, H; Dapas, B; Farra, R; Platz, J; Engel, S; Cjsareck, S; Kandolf, R; Teutsch, C; Klima, R; Triolo, G; Kuhn, A

2006-02-01

165

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

166

The Effect of Bedding System Selected by Manual Muscle Testing on Sleep-Related Cardiovascular Functions  

PubMed Central

Background. Different types of mattresses affect sleep quality and waking muscle power. Whether manual muscle testing (MMT) predicts the cardiovascular effects of the bedding system was explored using ten healthy young men. Methods. For each participant, two bedding systems, one inducing the strongest limb muscle force (strong bedding system) and the other inducing the weakest limb force (weak bedding system), were identified using MMT. Each bedding system, in total five mattresses and eight pillows of different firmness, was used for two continuous weeks at the participant's home in a random and double-blind sequence. A sleep log, a questionnaire, and a polysomnography were used to differentiate the two bedding systems. Results and Conclusion. Heart rate variability and arterial pressure variability analyses showed that the strong bedding system resulted in decreased cardiovascular sympathetic modulation, increased cardiac vagal activity, and increased baroreceptor reflex sensitivity during sleep as compared to the weak bedding system. Different bedding systems have distinct cardiovascular effects during sleep that can be predicted by MMT.

Kuo, Terry B. J.; Li, Jia-Yi; Lai, Chun-Ting; Huang, Yu-Chun; Hsu, Ya-Chuan; Yang, Cheryl C. H.

2013-01-01

167

Adenosinergic regulation of the cardiovascular system in the red-eared slider Trachemys scripta.  

PubMed

Few studies have investigated adenosinergic regulation of the cardiovascular system in reptiles. The haemodynamic effect of a bolus intra-arterial adenosine injection (2.5?Mkg(-1)) was investigated in nine anaesthetised red-eared sliders (Trachemys scripta). Adenosine caused a transient bradycardia, which was accompanied by systemic vasodilatation as evidenced by an increase in systemic flow and a decrease in systemic pressure. Meanwhile, pulmonary flow fell significantly. Both the bradycardia and increase in systemic conductance were significantly attenuated by theophylline (4mgkg(-1)), demonstrating an involvement of P1 receptors. These results suggest that adenosine is likely to play a significant role in reptile cardiovascular physiology. In turtles specifically, adenosinergic regulation may be particularly relevant during periods of apnoea. PMID:24726607

Joyce, William; Wang, Tobias

2014-08-01

168

Cardiovascular toxicity evaluation of silica nanoparticles in endothelial cells and zebrafish model.  

PubMed

Environmental exposure to nanomaterials is inevitable as nanomaterials become part of our daily life, and as a result, nanotoxicity research is gaining attention. However, most investigators focus on the evaluation of overall toxicity instead of a certain organism system. In this regard, the evaluation of cardiovascular effects of silica nanoparticles was preformed in vitro and in vivo. It's worth noting that silica nanoparticles induced cytotoxicity as well as oxidative stress and apoptosis. ROS and apoptosis were considered as major factor to endothelial cells dysfunction, involved in several molecular mechanisms of cardiovascular diseases. In vivo study, mortality, malformation, heart rate and whole-embryo cellular death were measured in zebrafish embryos. Results showed that silica nanoparticles induced pericardia toxicity and caused bradycardia. We also examined the expression of cardiovascular-related proteins in embryos by western blot analysis. Silica nanoparticles inhibited the expression of p-VEGFR2 and p-ERK1/2 as well as the downregulation of MEF2C and NKX2.5, revealed that silica nanoparticles could inhibit the angiogenesis and disturb the heart formation and development. In summary, our results suggest that exposure to silica nanoparticles is a possible risk factor to cardiovascular system. PMID:23663927

Duan, Junchao; Yu, Yongbo; Li, Yang; Yu, Yang; Sun, Zhiwei

2013-07-01

169

Computer modeling of cardiovascular fluid–structure interactions with the deforming-spatial-domain\\/stabilized space–time formulation  

Microsoft Academic Search

Hemodynamic factors such as the wall shear stress are believed to affect a number of cardiovascular diseases including atherosclerosis and aneurysm. Since resolving phenomena in a living human body is currently beyond the capabilities of in vivo measurement techniques, computer modeling is expected to play an important role in gaining a better understanding of the relationship between the cardiovascular diseases

Ryo Torii; Marie Oshima; Toshio Kobayashi; Kiyoshi Takagi; Tayfun E. Tezduyar

2006-01-01

170

Novel cardiovascular risk factors and cardiac event predictors in female inactive systemic lupus erythematosus patients.  

PubMed

Systemic lupus erythematosus (SLE) is associated with severe and premature cardiovascular disease, which cannot be explained by traditional risk factors alone. This study aims to investigate novel cardiovascular risk factors and cardiac event predictors in inactive SLE female patients who do not have any major cardiovascular risk factors. Twenty-five inactive (SLE disease activity index score <4) SLE female patients and 22 healthy control women were studied. SLE patients with a history of diabetes mellitus, hypertension, hyperlipidemia, smoking, or coronary artery disease (CAD) were excluded. Venous blood samples were analyzed for lipid subfractions and novel cardiovascular risk factors such as lipoprotein (a), homocysteine, fibrinogen, high-sensitivity C-reactive protein (hs-CRP), and serum amyloid A (SAA) levels. Endothelial dysfunction was assessed by flow-mediated dilatation (FMD) from the brachial artery at baseline and during reactive hyperemia. SLE patients and controls were similar in terms of age (40+/-10 years vs 38+/-10 years, p = NS). No significant difference was found between the groups regarding family history of premature CAD, blood pressure, body mass index, lipoprotein (a), homocysteine, fibrinogen, SAA, apoprotein A-1 and B levels. Compared with the controls, SLE patients had higher levels of hs-CRP [median (range): 1.82 (0.02-0.98) vs 0.68 (0.02-0.35), p=0.04]. FMD was lower in SLE patients than controls (7.1+/-2.1 vs 11.4+/-1.2%, p<0.001). Increased levels of hs-CRP and decreased FMD were found in inactive SLE patients. Increased hs-CRP levels may reflect ongoing low-grade inflammation that could be a cause of impaired FMD in SLE patients. These findings suggest that SLE patients without traditional major cardiovascular risk factors may have increased risk of cardiovascular disease and future cardiac events. PMID:16909327

Karadag, Omer; Calguneri, Meral; Atalar, Enver; Yavuz, Bunyamin; Akdogan, Ali; Kalyoncu, Umut; Bilgen, Sule Apras; Ozer, Necla; Ertenli, A Ihsan; Ovunc, Kenan; Kiraz, Sedat

2007-05-01

171

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.

2012-01-01

172

Noninvasive Assessment of the Developing Xenopus Cardiovascular System Using Optical Coherence Tomography  

NASA Astrophysics Data System (ADS)

Studies investigating normal and abnormal cardiac development are frequently limited by an inability to assess cardiovascular function within the intact organism. In this work, optical coherence tomography (OCT), a new method of micron-scale, noninvasive imaging based on the measurement of backscattered infrared light, was introduced for the high resolution assessment of structure and function in the developing Xenopus laevis cardiovascular system. Microstructural details, such as ventricular size and wall positions, were delineated with OCT at 16-? m resolution and correlated with histology. Three-dimensional representation of the cardiovascular system also was achieved by repeated cross-sectional imaging at intervals of 25 ? m. In addition to structural information, OCT provides high speed in vivo axial ranging and imaging, allowing quantitative dynamic activity, such as ventricular ejection fraction, to be assessed. The sensitivity of OCT for dynamic assessment was demonstrated with an inotropic agent that altered cardiac function and dimensions. Optical coherence tomography is an attractive new technology for assessing cardiovascular development because of its high resolution, its ability to image through nontransparent structures, and its inexpensive portable design. In vivo and in vitro imaging are performed at a resolution approaching that of histopathology without the need for animal killing.

Boppart, Stephen A.; Tearney, Gary J.; Bouma, Brett E.; Southern, James F.; Brezinski, Mark E.; Fujimoto, James G.

1997-04-01

173

Projections of preventable risks for cardiovascular disease in Canada to 2021: a microsimulation modelling approach  

PubMed Central

Background Reductions in preventable risks associated with cardiovascular disease have contributed to a steady decrease in its incidence over the past 50 years in most developed countries. However, it is unclear whether this trend will continue. Our objective was to examine future risk by projecting trends in preventable risk factors in Canada to 2021. Methods We created a population-based microsimulation model using national data on births, deaths and migration; socioeconomic data; cardiovascular disease risk factors; and algorithms for changes in these risk factors (based on sociodemographic characteristics and previous cardiovascular disease risk). An initial population of 22.5 million people, representing the Canadian adult population in 2001, had 13 characteristics including the risk factors used in clinical risk prediction. There were 6.1 million potential exposure profiles for each person each year. Outcome measures included annual prevalence of risk factors (smoking, obesity, diabetes, hypertension and lipid levels) and of co-occurring risks. Results From 2003 to 2009, the projected risks of cardiovascular disease based on the microsimulation model closely approximated those based on national surveys. Except for obesity and diabetes, all risk factors were projected to decrease through to 2021. The largest projected decreases were for the prevalence of smoking (from 25.7% in 2001 to 17.7% in 2021) and uncontrolled hypertension (from 16.1% to 10.8%). Between 2015 and 2017, obesity was projected to surpass smoking as the most prevalent risk factor. Interpretation Risks of cardiovascular disease are projected to decrease modestly in Canada, leading to a likely continuing decline in its incidence.

Manuel, Douglas G.; Tuna, Meltem; Hennessy, Deirdre; Okhmatovskaia, Anya; Fines, Philippe; Tanuseputro, Peter; Tu, Jack V.; Flanagan, William

2014-01-01

174

An exceptionally preserved arthropod cardiovascular system from the early Cambrian.  

PubMed

The assumption that amongst internal organs of early arthropods only the digestive system withstands fossilization is challenged by the identification of brain and ganglia in early Cambrian fuxianhuiids and megacheirans from southwest China. Here we document in the 520-million-year-old Chengjiang arthropod Fuxianhuia protensa an exceptionally preserved bilaterally symmetrical organ system corresponding to the vascular system of extant arthropods. Preserved primarily as carbon, this system includes a broad dorsal vessel extending through the thorax to the brain where anastomosing branches overlap brain segments and supply the eyes and antennae. The dorsal vessel provides segmentally paired branches to lateral vessels, an arthropod ground pattern character, and extends into the anterior part of the abdomen. The addition of its vascular system to documented digestive and nervous systems resolves the internal organization of F. protensa as the most completely understood of any Cambrian arthropod, emphasizing complexity that had evolved by the early Cambrian. PMID:24704943

Ma, Xiaoya; Cong, Peiyun; Hou, Xianguang; Edgecombe, Gregory D; Strausfeld, Nicholas J

2014-01-01

175

Motivational Systems and Stress-Related Cardiovascular Reactivity  

Microsoft Academic Search

This study examined the relation of motivational systems to patterns of autonomic responses to stress. Specifically, we examined patterns of physiological response resulting from differential activation of motivational systems for behavioral approach and behavioral inhibition. We also examined the relation of these motivational systems to threat and challenge responses to potential stress. Self-report, cardiac measures (i.e., pre-injection period, or PEP,

Joe Tomaka; Rebecca L. Palacios-Esquivel

1997-01-01

176

Behavioral and cardiovascular changes in the chronic mild stress model of depression.  

PubMed

Depression is a multifaceted psychological disorder that involves changes in behavior, neuroendocrine function, and physiological responses. The present study investigated multiple behavioral and cardiovascular consequences in the chronic mild stress (CMS) rodent model of depression. Rats were exposed to 4 weeks of CMS followed by 4 weeks of a stress-free recovery period. Sucrose intake, a measure of anhedonia, and spontaneous locomotor activity were measured weekly throughout the study, and cardiovascular function tests were conducted at the completion of the protocol. The results indicate that CMS results in anhedonia and reduced locomotor activity, as well as elevated heart rate (HR), reduced HR variability, and elevated sympathetic cardiac tone. The behavioral effects of CMS recovered to baseline (prestress) levels during the recovery period; however, cardiovascular changes were observed following the recovery of sucrose intake and activity levels. The present findings suggest that behavioral changes that are indicative of anhedonia and locomotor alterations associated with depression are dissociable from long-term cardiovascular changes induced by CMS. PMID:12782226

Grippo, Angela J; Beltz, Terry G; Johnson, Alan Kim

2003-04-01

177

Cardiovascular autonomic dysfunction in systemic lupus, rheumatoid arthritis, primary Sjögren syndrome and other autoimmune diseases.  

PubMed

Neurological manifestations are known to occur in patients with autoimmune diseases, often subclinically, but autonomic nervous system (ANS) involvement has rarely been studied, and studies have shown conflicting results. We performed cardiovascular ANS assessment in 125 patients with autoimmune diseases in this case-control study, including 54 patients with systemic lupus erythematosus (SLE), 39 with rheumatoid arthritis (RA), 20 with primary Sjbgren syndrome (pSS), eight patients with polymyalgia rheumatica (PR), four patients with scleroderma (Ssc) and 35 healthy control subjects. The control group was formed to approximately match the mean age of SLE, RA and pSS patients; controls did not differ significantly by gender from the autoimmune pations. All patients with were in stable condition. Autonomic nervous system dysfunction was diagnosed by applying cardiovascular reflex tests according to Ewing, and was considered to exist if at least two tests were positive. Vagal dysfunction was established by applying three tests: Valsalva manoeuvre, deep breathing test, and heart rate response to standing. Sympathetic dysfunction was examined by applying two tests: blood pressure response to standing and handgrip test. In all cardiovascular reflex tests, frequencies of abnormal results were significantly higher among the patients than among the controls (P < 0.05). The difference between the autoimmune patients and the controls was particularly significant in sympathetic and parasympathetic tests, with P < 0.0001. No correlation was found between disease duration, clinical manifestations, cardiovascular risk factors and diseases activity on the one hand, and ANS dysfunction on the other hand. Cardiovascular autonomic dysfunction was revealed in the majority of autoimmune patients. PMID:17432103

Stojanovich, L; Milovanovich, B; de Luka, S R; Popovich-Kuzmanovich, D; Bisenich, V; Djukanovich, B; Randjelovich, T; Krotin, M

2007-01-01

178

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

179

Protein O-GlcNAcylation: a new signaling paradigm for the cardiovascular system.  

PubMed

The posttranslational modification of serine and threonine residues of nuclear and cytoplasmic proteins by the O-linked attachment of the monosaccharide beta-N-acetylglucosamine (O-GlcNAc) is a highly dynamic and ubiquitous protein modification. Protein O-GlcNAcylation is rapidly emerging as a key regulator of critical biological processes including nuclear transport, translation and transcription, signal transduction, cytoskeletal reorganization, proteasomal degradation, and apoptosis. Increased levels of O-GlcNAc have been implicated as a pathogenic contributor to glucose toxicity and insulin resistance, which are both major hallmarks of diabetes mellitus and diabetes-related cardiovascular complications. Conversely, there is a growing body of data demonstrating that the acute activation of O-GlcNAc levels is an endogenous stress response designed to enhance cell survival. Reports on the effect of altered O-GlcNAc levels on the heart and cardiovascular system have been growing rapidly over the past few years and have implicated a role for O-GlcNAc in contributing to the adverse effects of diabetes on cardiovascular function as well as mediating the response to ischemic injury. Here, we summarize our present understanding of protein O-GlcNAcylation and its effect on the regulation of cardiovascular function. We examine the pathways regulating protein O-GlcNAcylation and discuss, in more detail, our understanding of the role of O-GlcNAc in both mediating the adverse effects of diabetes as well as its role in mediating cellular protective mechanisms in the cardiovascular system. In addition, we also explore the parallels between O-GlcNAc signaling and redox signaling, as an alternative paradigm for understanding the role of O-GlcNAcylation in regulating cell function. PMID:19028792

Laczy, Boglarka; Hill, Bradford G; Wang, Kai; Paterson, Andrew J; White, C Roger; Xing, Dongqi; Chen, Yiu-Fai; Darley-Usmar, Victor; Oparil, Suzanne; Chatham, John C

2009-01-01

180

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

181

A New Oxidative Stress Model, 2,2-Azobis(2-Amidinopropane) Dihydrochloride Induces Cardiovascular Damages in Chicken Embryo  

PubMed Central

It is now well established that the developing embryo is very sensitive to oxidative stress, which is a contributing factor to pregnancy-related disorders. However, little is known about the effects of reactive oxygen species (ROS) on the embryonic cardiovascular system due to a lack of appropriate ROS control method in the placenta. In this study, a small molecule called 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH), a free radicals generator, was used to study the effects of oxidative stress on the cardiovascular system during chick embryo development. When nine-day-old (stage HH 35) chick embryos were treated with different concentrations of AAPH inside the air chamber, it was established that the LD50 value for AAPH was 10 µmol/egg. At this concentration, AAPH was found to significantly reduce the density of blood vessel plexus that was developed in the chorioallantoic membrane (CAM) of HH 35 chick embryos. Impacts of AAPH on younger embryos were also examined and discovered that it inhibited the development of vascular plexus on yolk sac in HH 18 embryos. AAPH also dramatically repressed the development of blood islands in HH 3+ embryos. These results implied that AAPH-induced oxidative stress could impair the whole developmental processes associated with vasculogenesis and angiogenesis. Furthermore, we observed heart enlargement in the HH 40 embryo following AAPH treatment, where the left ventricle and interventricular septum were found to be thickened in a dose-dependent manner due to myocardiac cell hypertrophy. In conclusion, oxidative stress, induced by AAPH, could lead to damage of the cardiovascular system in the developing chick embryo. The current study also provided a new developmental model, as an alternative for animal and cell models, for testing small molecules and drugs that have anti-oxidative activities.

Li, Xiao-Di; Yi, Ruo-Nan; Wang, Xiao-Yu; Tsoi, Bun; Lee, Kenneth Ka Ho; Abe, Keiichi; Yang, Xuesong; Kurihara, Hiroshi

2013-01-01

182

A new oxidative stress model, 2,2-azobis(2-amidinopropane) dihydrochloride induces cardiovascular damages in chicken embryo.  

PubMed

It is now well established that the developing embryo is very sensitive to oxidative stress, which is a contributing factor to pregnancy-related disorders. However, little is known about the effects of reactive oxygen species (ROS) on the embryonic cardiovascular system due to a lack of appropriate ROS control method in the placenta. In this study, a small molecule called 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH), a free radicals generator, was used to study the effects of oxidative stress on the cardiovascular system during chick embryo development. When nine-day-old (stage HH 35) chick embryos were treated with different concentrations of AAPH inside the air chamber, it was established that the LD50 value for AAPH was 10 µmol/egg. At this concentration, AAPH was found to significantly reduce the density of blood vessel plexus that was developed in the chorioallantoic membrane (CAM) of HH 35 chick embryos. Impacts of AAPH on younger embryos were also examined and discovered that it inhibited the development of vascular plexus on yolk sac in HH 18 embryos. AAPH also dramatically repressed the development of blood islands in HH 3+ embryos. These results implied that AAPH-induced oxidative stress could impair the whole developmental processes associated with vasculogenesis and angiogenesis. Furthermore, we observed heart enlargement in the HH 40 embryo following AAPH treatment, where the left ventricle and interventricular septum were found to be thickened in a dose-dependent manner due to myocardiac cell hypertrophy. In conclusion, oxidative stress, induced by AAPH, could lead to damage of the cardiovascular system in the developing chick embryo. The current study also provided a new developmental model, as an alternative for animal and cell models, for testing small molecules and drugs that have anti-oxidative activities. PMID:23469224

He, Rong-Rong; Li, Yan; Li, Xiao-Di; Yi, Ruo-Nan; Wang, Xiao-Yu; Tsoi, Bun; Lee, Kenneth Ka Ho; Abe, Keiichi; Yang, Xuesong; Kurihara, Hiroshi

2013-01-01

183

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.

Maron, Bradley A.; Tang, Shiow-Shih

2013-01-01

184

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.

Shadden, Shawn C.; Taylor, Charles A.

2013-01-01

185

Prototype for an organ system (liver) localization cardiovascular catheter  

NASA Astrophysics Data System (ADS)

This study describes the function and potential clinical utility of a sensor which can serve as a guidance mechanism allowing for the selective cannulation of the hepatic venous system without the need for additional imaging technology. The sensor is based upon a homogeneous affinity fluorescence assay system utilizing the lectin Ricinus cummunis agglutinin I and covalently linked to the fluorophol Alexa 488 and its conjugate polydextran labeled with rhodamine and lactose. The affinity between these two macromolecules is sensitive to ambient galactose concentration which exists as a steep gradient at the hepatic venous/vena caval junction allowing this anatomic region to be discriminated from irrelevant regions. This sensor system permits venous access for additional monitoring approaches such as venous oximetry.

Ballerstadt, Ralph; Dahn, Michael S.; Lange, M. Patricia; Schultz, Jerome S.

1999-07-01

186

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

187

Right ventricular overload and cardiovascular neuroendocrine derangement in systemic sclerosisq  

Microsoft Academic Search

Aim Systemic sclerosis (SSc) may be associated with right ventricular overload, sec- ondary to pulmonary hypertension. In heart failure patients, neuroendocrine derange- ments can influence clinical evolution and prognosis. The aim of this study was to investigate neurohormonal control affected in SSc patients with and without right ventricular impairment. Methods and results A prospective series of 28 patients with SSc

Michele Emdina; Carlo Marini; Claudio Passino; Dilia Giuggioli; Bruno Formichi; Clodoveo Ferrie; Jaleh Khabirinejad; Roberta Poletti; Concetta Prontera; Annalisa Iervasi; Antonio L'Abbatef

188

Improving the cost-effectiveness of cardiovascular disease prevention in Australia: a modelling study  

PubMed Central

Background Cardiovascular disease is the leading cause of death worldwide. Like many countries, Australia is currently changing its guidelines for cardiovascular disease prevention from drug treatment for everyone with ‘high blood pressure’ or ‘high cholesterol’, to prevention based on a patient’s absolute risk. In this research, we model cost-effectiveness of cardiovascular disease prevention with blood pressure and lipid drugs in Australia under three different scenarios: (1) the true current practice in Australia; (2) prevention as intended under the current guidelines; and (3) prevention according to proposed absolute risk levels. We consider the implications of changing to absolute risk-based cardiovascular disease prevention, for the health of the Australian people and for Government health sector expenditure over the long term. Methods We evaluate cost-effectiveness of statins, diuretics, ACE inhibitors, calcium channel blockers and beta-blockers, for Australian men and women, aged 35 to 84?years, who have never experienced a heart disease or stroke event. Epidemiological changes and health care costs are simulated by age and sex in a discrete time Markov model, to determine total impacts on population health and health sector costs over the lifetime, from which we derive cost-effectiveness ratios in 2008 Australian dollars per quality-adjusted life year. Results Cardiovascular disease prevention based on absolute risk is more cost-effective than prevention under the current guidelines based on single risk factor thresholds, and is more cost-effective than the current practice, which does not follow current clinical guidelines. Recommending blood pressure-lowering drugs to everyone with at least 5% absolute risk and statin drugs to everyone with at least 10% absolute risk, can achieve current levels of population health, while saving $5.4 billion for the Australian Government over the lifetime of the population. But savings could be as high as $7.1 billion if Australia could match the cheaper price of statin drugs in New Zealand. Conclusions Changing to absolute risk-based cardiovascular disease prevention is highly recommended for reducing health sector spending, but the Australian Government must also consider measures to reduce the cost of statin drugs, over and above the legislated price cuts of November 2010.

2012-01-01

189

Links between allergy and cardiovascular or hemostatic system.  

PubMed

In addition to a well-known immunologic background of atherosclerosis and influences of inflammation on arterial and venous thrombosis, there is growing evidence for the presence of links between allergy and vascular or thrombotic disorders. In this interpretative review, five pretty well-documented areas of such overlap are described and discussed, including: (1) links between atherosclerosis and immunoglobulin E or atopy, (2) mutual effects of blood lipids and allergy, (3) influence of atopy and related disorders on venous thromboembolism, (4) the role of platelets in allergic diseases, and (5) the functions of protein C system in atopic disorders. PMID:24315352

Potaczek, Daniel P

2014-01-01

190

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

191

In vitro cardiovascular system emulator (bioreactor) for the simulation of normal and diseased conditions with and without mechanical circulatory support.  

PubMed

This article presents a new device designed to simulate in vitro flow rates, pressures, and other parameters representing normal and diseased conditions of the human cardiovascular system. Such devices are sometimes called bioreactors or "mock" simulator of cardiovascular loops (SCVLs) in literature. Most SCVLs simulate the systemic circulation only and have inherent limitations in studying the interaction of left and right sides of circulation. Those SCVLs that include both left and right sides of the circulation utilize header reservoirs simulating cycles with constant atrial pressures. The SCVL described in this article includes models for all four chambers of the heart, and the systemic and pulmonary circulation loops. Each heart chamber is accurately activated by a separate linear motor to simulate the suction and ejection stages, thus capturing important features in the perfusion waveforms. Four mechanical heart valves corresponding to mitral, pulmonary, tricuspid, and aortic are used to control the desired unidirectional flow. This SCVL can emulate different physiological and pathological conditions of the human cardiovascular system by controlling the different parameters of blood circulation through the vascular tree (mainly the resistance, compliance, and elastance of the heart chambers). In this study, four cases were simulated: healthy, congestive heart failure, left ventricular diastolic dysfunction conditions, and left ventricular dysfunction with the addition of a mechanical circulatory support (MCS) device. Hemodynamic parameters including resistance, pressure, and flow have been investigated at aortic sinus, carotid artery, and pulmonary artery, respectively. The addition of an MCS device resulted in a significant reduction in mean blood pressure and re-establishment of cardiac output. In all cases, the experimental results are compared with human physiology and numerical simulations. The results show the capability of the SCVL to replicate various physiological and pathological conditions with and without MCS. PMID:23758568

Ruiz, Paula; Rezaienia, Mohammad Amin; Rahideh, Akbar; Keeble, Thomas R; Rothman, Martin T; Korakianitis, Theodosios

2013-06-01

192

Autonomic Insufficiency in Pupillary and Cardiovascular Systems in Parkinson's Disease  

PubMed Central

Background In Parkinson's disease (PD), neurodegenerative changes have been observed in autonomic pathways involving multiple organ systems. We explore pupillary and cardiac autonomic measures as physiological manifestations of PD neurodegeneration. Methods Pupil measures (pupillary unrest (spontaneous changes of pupil diameter in darkness), constriction velocity and redilation velocity) were assessed in 35 participants (17 PD, 18 controls). Simultaneous cardiac measures (respiratory sinus arrythmia during deep breathing, Valsalva ratio, resting heart rate variability (HRV), orthostatic change in blood pressure and orthostatic change in heart rate) were obtained. Nonparametric statistics were used to compare PD with control participants and to calculate correlation coefficients between pupillary and cardiac measures. Results Pupillary unrest and orthostatic decreases in systolic blood pressure were greater in PD than controls. Respiratory sinus arrythmia during deep breathing and resting HRV were lower in PD. Among all participants, there was a negative correlation between HRV and redilation velocity and a positive correlation between orthostatic change in heart rate and pupillary unrest. A modifying effect of PD was found on the association between high frequency HRV and pupillary unrest. Conclusions Results demonstrate simultaneous autonomic dysfunction in both pupillary and cardiac systems in PD. The correlations between pupillary and cardiac measures suggest shared central centers of autonomic integration, while the modifying effect of PD may reflect autonomic effects of PD-related pathology not present in controls.

Jain, Samay; Siegle, Greg J.; Gu, Chen; Moore, Charity G.; Ivanco, Larry S.; Jennings, J. Richard; Steinhauer, Stuart R.; Studenski, Stephanie; Greenamyre, J. Timothy

2010-01-01

193

Minimizing risk of nephrogenic systemic fibrosis in cardiovascular magnetic resonance.  

PubMed

Nephrogenic Systemic Fibrosis is a rare condition appearing only in patients with severe renal impairment or failure and presents with dermal lesions and involvement of internal organs. Although many cases are mild, an estimated 5% have a progressive debilitating course. To date, there is no known effective treatment thus stressing the necessity of ample prevention measures. An association with the use of Gadolinium based contrast agents (GBCA) makes Nephrogenic Systemic Fibrosis a potential side effect of contrast enhanced magnetic resonance imaging and offers the opportunity for prevention by limiting use of gadolinium based contrast agents in renal failure patients. In itself toxic, Gadolinium is embedded into chelates that allow its safe use as a contrast agent. One NSF theory is that Gadolinium chelates distribute into the extracellular fluid compartment and set Gadolinium ions free, depending on multiple factors among which the duration of chelates exposure is directly related to the renal function. Major medical societies both in Europe and in North America have developed guidelines for the usage of GBCA. Since the establishment of these guidelines and the increased general awareness of this condition, the occurrence of NSF has been nearly eliminated. Giving an overview over the current knowledge of NSF pathobiochemistry, pathogenesis and treatment options this review focuses on the guidelines of the European Medicines Agency, the European Society of Urogenital Radiology, the FDA and the American College of Radiology from 2008 up to 2011 and the transfer of this knowledge into every day practice. PMID:22607376

Reiter, Theresa; Ritter, Oliver; Prince, Martin R; Nordbeck, Peter; Wanner, Christoph; Nagel, Eike; Bauer, Wolfgang Rudolf

2012-01-01

194

Minimizing Risk of Nephrogenic systemic fibrosis in Cardiovascular Magnetic Resonance  

PubMed Central

Nephrogenic Systemic Fibrosis is a rare condition appearing only in patients with severe renal impairment or failure and presents with dermal lesions and involvement of internal organs. Although many cases are mild, an estimated 5?% have a progressive debilitating course. To date, there is no known effective treatment thus stressing the necessity of ample prevention measures. An association with the use of Gadolinium based contrast agents (GBCA) makes Nephrogenic Systemic Fibrosis a potential side effect of contrast enhanced magnetic resonance imaging and offers the opportunity for prevention by limiting use of gadolinium based contrast agents in renal failure patients. In itself toxic, Gadolinium is embedded into chelates that allow its safe use as a contrast agent. One NSF theory is that Gadolinium chelates distribute into the extracellular fluid compartment and set Gadolinium ions free, depending on multiple factors among which the duration of chelates exposure is directly related to the renal function. Major medical societies both in Europe and in North America have developed guidelines for the usage of GBCA. Since the establishment of these guidelines and the increased general awareness of this condition, the occurrence of NSF has been nearly eliminated. Giving an overview over the current knowledge of NSF pathobiochemistry, pathogenesis and treatment options this review focuses on the guidelines of the European Medicines Agency, the European Society of Urogenital Radiology, the FDA and the American College of Radiology from 2008 up to 2011 and the transfer of this knowledge into every day practice.

2012-01-01

195

The influence of selective vitamin D receptor activator paricalcitol on cardiovascular system and cardiorenal protection  

PubMed Central

The ubiquitous distribution of vitamin D receptors in the human body is responsible for the pleiotropic effects of vitamin D-receptor activation. We discuss the possible beneficial effects of a selective activator of vitamin D receptor, paricalcitol, on the cardiovascular system in chronic heart failure patients and chronic kidney patients, in light of new trials. Paricalcitol should provide additional clinical benefits over the standard treatment for chronic kidney and heart failure, especially in cases of cardiorenal syndrome.

Duplancic, Darko; Cesarik, Marijan; Poljak, Nikola Kolja; Radman, Maja; Kovacic, Vedran; Radic, Josipa; Rogosic, Veljko

2013-01-01

196

A composite high-frame-rate system for clinical cardiovascular imaging  

Microsoft Academic Search

High frame-rate ultrasound RF data acquisition has been proved to be critical for novel cardiovascular imaging techniques, such as high-precision myocardial elastography, pulse wave imaging (PWI), and electromechanical wave imaging (EWI). To overcome the frame-rate limitations on standard clinical ultrasound systems, we developed an automated method for multi-sector ultrasound imaging through retrospective electrocardiogram (ECG) gating on a clinically used open

Shougang Wang; Wei-ning Lee; J. Provost; Jianwen Luo; E. E. Konofagou

2008-01-01

197

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

198

The endothelin system as a therapeutic target in cardiovascular disease: great expectations or bleak house?  

PubMed Central

There is considerable evidence that the potent vasoconstrictor endothelin-1 (ET-1) contributes to the pathogenesis of a variety of cardiovascular diseases. As such, pharmacological manipulation of the ET system might represent a promising therapeutic goal. Many clinical trials have assessed the potential of ET receptor antagonists in cardiovascular disease, the most positive of which have resulted in the licensing of the mixed ET receptor antagonist bosentan, and the selective ETA receptor antagonists, sitaxsentan and ambrisentan, for the treatment of pulmonary arterial hypertension (PAH). In contrast, despite encouraging data from in vitro and animal studies, outcomes in human heart failure have been disappointing, perhaps illustrating the risk of extrapolating preclinical work to man. Many further potential applications of these compounds, including resistant hypertension, chronic kidney disease, connective tissue disease and sub-arachnoid haemorrhage are currently being investigated in the clinic. Furthermore, experience from previous studies should enable improved trial design and scope remains for development of improved compounds and alternative therapeutic strategies. Although ET-converting enzyme inhibitors may represent one such alternative, there have been relatively few suitable compounds developed, and consequently, clinical experience with these agents remains extremely limited. Recent advances, together with an increased understanding of the biology of the ET system provided by improved experimental tools (including cell-specific transgenic deletion of ET receptors), should allow further targeting of clinical trials to diseases in which ET is involved and allow the therapeutic potential for targeting the ET system in cardiovascular disease to be fully realized.

Kirkby, N S; Hadoke, P W F; Bagnall, A J; Webb, D J

2007-01-01

199

Isorhynchophylline: A plant alkaloid with therapeutic potential for cardiovascular and central nervous system diseases.  

PubMed

Uncaria species (Gouteng in Chinese) have been used as a plant medicine to treat ailments of cardiovascular and central nervous systems. As the main alkaloid constituent of Uncaria species, isorhynchophylline has drawn extensive attention toward antihypertensive and neuroprotective activities in recent years. Isorhynchophylline mainly acts on cardiovascular and central nervous systems diseases including hypertension, brachycardia, arrhythmia, and sedation, vascular dementia, and amnesia. Isorhynchophylline also has effects on anticoagulation, inhibition vascular smooth muscle cell apoptosis and proliferation, anti-multidrug resistant of lung cells, anti-endotoxemic, and antispasmodic. The active mechanisms are related to modulation on calcium ion channel, protection neural and neuroglial cells against ?-amyloid(25-35)-induced neurotoxicity and via inducing autophagy. As a candidate drug of several cardiovascular and central nervous systems diseases, isorhynchophylline will attract scientists to pursue the potential related pharmacological effects and its mechanism with new technologies. But relatively few clinical application of isorhynchophylline has been conducted on its pharmacological activities. It requires more in vivo validations and further investigations of antihypertensive and neuroprotective mechanisms of isorhynchophylline. PMID:22406453

Zhou, Ji-Yin; Zhou, Shi-Wen

2012-06-01

200

Physiology and pharmacology of the cardiovascular adrenergic system  

PubMed Central

Heart failure (HF), the leading cause of death in the western world, ensues in response to cardiac injury or insult and represents the inability of the heart to adequately pump blood and maintain tissue perfusion. It is characterized by complex interactions of several neurohormonal mechanisms that get activated in the syndrome in order to try and sustain cardiac output in the face of decompensating function. The most prominent among these neurohormonal mechanisms is the adrenergic (or sympathetic) nervous system (ANS), whose activity and outflow are greatly elevated in HF. Acutely, provided that the heart still works properly, this activation of the ANS will promptly restore cardiac function according to the fundamental Frank-Starling law of cardiac function. However, if the cardiac insult persists over time, this law no longer applies and ANS will not be able to sustain cardiac function. This is called decompensated HF, and the hyperactive ANS will continue to “push” the heart to work at a level much higher than the cardiac muscle can handle. From that point on, ANS hyperactivity becomes a major problem in HF, conferring significant toxicity to the failing heart and markedly increasing its morbidity and mortality. The present review discusses the role of the ANS in cardiac physiology and in HF pathophysiology, the mechanisms of regulation of ANS activity and how they go awry in chronic HF, and, finally, the molecular alterations in heart physiology that occur in HF along with their pharmacological and therapeutic implications for the failing heart.

Lymperopoulos, Anastasios

2013-01-01

201

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.

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

2014-01-01

202

Impact of the human circadian system, exercise, and their interaction on cardiovascular function  

PubMed Central

The risk of adverse cardiovascular events peaks in the morning (?9:00 AM) with a secondary peak in the evening (?8:00 PM) and a trough at night. This pattern is generally believed to be caused by the day/night distribution of behavioral triggers, but it is unknown whether the endogenous circadian system contributes to these daily fluctuations. Thus, we tested the hypotheses that the circadian system modulates autonomic, hemodynamic, and hemostatic risk markers at rest, and that behavioral stressors have different effects when they occur at different internal circadian phases. Twelve healthy adults were each studied in a 240-h forced desynchrony protocol in dim light while standardized rest and exercise periods were uniformly distributed across the circadian cycle. At rest, there were large circadian variations in plasma cortisol (peak-to-trough ?85% of mean, peaking at a circadian phase corresponding to ?9:00 AM) and in circulating catecholamines (epinephrine, ?70%; norepinephrine, ?35%, peaking during the biological day). At ?8:00 PM, there was a circadian peak in blood pressure and a trough in cardiac vagal modulation. Sympathetic variables were consistently lowest and vagal markers highest during the biological night. We detected no simple circadian effect on hemostasis, although platelet aggregability had two peaks: at ?noon and ?11:00 PM. There was circadian modulation of the cardiovascular reactivity to exercise, with greatest vagal withdrawal at ?9:00 AM and peaks in catecholamine reactivity at ?9:00 AM and ?9:00 PM. Thus, the circadian system modulates numerous cardiovascular risk markers at rest as well as their reactivity to exercise, with resultant profiles that could potentially contribute to the day/night pattern of adverse cardiovascular events.

Scheer, Frank A. J. L.; Hu, Kun; Evoniuk, Heather; Kelly, Erin E.; Malhotra, Atul; Hilton, Michael F.; Shea, Steven A.

2010-01-01

203

Hemodynamic effects of various support modes of continuous flow LVADs on the cardiovascular system: A numerical study.  

PubMed

Background The aim of this study was to determine the hemodynamic effects of various support modes of continuous flow left ventricular assist devices (CF-LVADs) on the cardiovascular system using a numerical cardiovascular system model. Material and Methods Three support modes were selected for controlling the CF-LVAD: constant flow mode, constant speed mode, and constant pressure head mode of CF-LVAD. The CF-LVAD is established between the left ventricular apex and the ascending aorta, and was incorporated into the numerical model. Various parameters were evaluated, including the blood assist index (BAI), the left ventricular external work (LVEW), the energy of blood flow (EBF), pulsatility index (PI), and surplus hemodynamic energy (SHE). Results The results show that the constant flow mode, when compared to the constant speed mode and the constant pressure head mode, increases LVEW by 31% and 14%, and EBF by 21% and 15%, respectively, indicating that this mode achieved the best ventricular unloading among the 3 support modes. As BAI is increased, PI and SHE are gradually decreased, whereas PI of the constant pressure head reaches the maximum value. Conclusions The study demonstrates that the continuous flow control mode of the CF-LVAD may achieve the highest ventricular unloading. In contrast, the constant rotational speed mode permits the optimal blood perfusion. Finally, the constant pressure head strategy, permitting optimal pulsatility, should optimize the vascular function. PMID:24793178

Song, Zhiming; Gu, Kaiyun; Gao, Bin; Wan, Feng; Chang, Yu; Zeng, Yi

2014-01-01

204

Hemodynamic effects of various support modes of continuous flow LVADs on the cardiovascular system: A numerical study  

PubMed Central

Background The aim of this study was to determine the hemodynamic effects of various support modes of continuous flow left ventricular assist devices (CF-LVADs) on the cardiovascular system using a numerical cardiovascular system model. Material/Methods Three support modes were selected for controlling the CF-LVAD: constant flow mode, constant speed mode, and constant pressure head mode of CF-LVAD. The CF-LVAD is established between the left ventricular apex and the ascending aorta, and was incorporated into the numerical model. Various parameters were evaluated, including the blood assist index (BAI), the left ventricular external work (LVEW), the energy of blood flow (EBF), pulsatility index (PI), and surplus hemodynamic energy (SHE). Results The results show that the constant flow mode, when compared to the constant speed mode and the constant pressure head mode, increases LVEW by 31% and 14%, and EBF by 21% and 15%, respectively, indicating that this mode achieved the best ventricular unloading among the 3 support modes. As BAI is increased, PI and SHE are gradually decreased, whereas PI of the constant pressure head reaches the maximum value. Conclusions The study demonstrates that the continuous flow control mode of the CF-LVAD may achieve the highest ventricular unloading. In contrast, the constant rotational speed mode permits the optimal blood perfusion. Finally, the constant pressure head strategy, permitting optimal pulsatility, should optimize the vascular function.

Song, Zhiming; Gu, Kaiyun; Gao, Bin; Wan, Feng; Chang, Yu; Zeng, Yi

2014-01-01

205

Protective effects of red wine polyphenolic compounds on the cardiovascular system.  

PubMed

Phenolic phytochemicals are widely distributed in the plant kingdom. In terms of protective effects on organisms, the group of polyphenols is the most important. In various experiments, it has been shown that selected polyphenols, mainly flavonoids, confer protective effects on the cardiovascular system and have anti-cancer, antiviral and antiallergic properties. In coronary artery disease, the protective effects are due mainly to antithrombic, antioxidant, anti-ischemic and vasorelaxant properties of flavonoids. Flavonoids are low molecular weight compounds composed of a three-ring structure with various substitutions, which appear to be responsible for the antioxidant and antiproliferative properties. It has been hypothesized that the low incidence of coronary artery disease in the French population may be partially related to the pharmacological properties of polyphenolic compounds present in red wine. Many epidemiological studies have shown that regular flavonoid intake is associated with reduced risk of cardiovascular diseases. PMID:20428452

Zenebe, W; Pechánová, O; Bernátová, I

2001-01-01

206

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.

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

2013-01-01

207

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

208

Physiolab: A new laboratory for the study of the cardio-vascular system  

NASA Astrophysics Data System (ADS)

On the basis of the experience gained during the previous french-russian missions on board MIR about the adaptation processes of the cardio-vascular system, a new laboratory has been designed. The objective of this "PHYSIOLAB" is to have a better understanding of the mechanisms underlying the changes in the cardio-vascular system, with a special emphasis on the phenomenon of cardio-vascular deconditioning after landing. Beyond these scientific objectives, it is also intended to use PHYSIOLAB to help in the medical monitoring on-board MIR, during functional tests such as LBNP. PHYSIOLAB will be set up in MIR by the French cosmonaut during the next french-russian CASSIOPEE mission in 1996. Its architecture is based on a central unit, which controls the experimental protocols, records the results and provides an interface for transmission to the ground via telemetry. Different specific modules are used for the acquisition of various physiological parameters. This PHYSIOLAB under development for the CASSIOPEE mission should evolve towards a more ambitious laboratory, whose definition would take into account the results obtained with the first version of PHYSIOLAB. This "second generation" laboratory should be developed in the frame of wide international cooperation.

Marsal, O.; André-Deshays, C.; Cauquil, D.; Kotovskaya, A.; Gratchev, V.; Noskin, A.

209

The love of a lifetime: 5-HT in the cardiovascular system.  

PubMed

Serotonin [5-hydroxytryptamine (5-HT)] is an amine made from the essential amino acid tryptophan. 5-HT serves numerous functions in the body, including mood, satiety, and gastrointestinal function. Less understood is the role 5-HT plays in the cardiovascular system, although 5-HT receptors have been localized to every important cardiovascular organ and 5-HT-induced changes in physiological function attributed to activation of these receptors. This manuscript relates a few scientific stories that test the idea that 5-HT is important to the control of normal vascular tone, more so in the hypertensive condition. Currently, our laboratory is faced with two different lines of experimentation from which one could draw vastly different conclusions as to the ability of 5-HT to modify endogenous vascular tone and blood pressure. Studies point to 5-HT being important in maintaining high blood pressure, but other studies solidly support the ability of 5-HT to reduce elevated blood pressure. This work underscores that our knowledge of the functions of 5-HT in the cardiovascular system is significantly incomplete. As such, this field is an exciting one in which to be, because there are superb questions to be asked. PMID:18753260

Watts, Stephanie W

2009-02-01

210

Investigating Properties of the Cardiovascular System Using Innovative Analysis Algorithms Based on Ensemble Empirical Mode Decomposition  

PubMed Central

Cardiovascular system is known to be nonlinear and nonstationary. Traditional linear assessments algorithms of arterial stiffness and systemic resistance of cardiac system accompany the problem of nonstationary or inconvenience in practical applications. In this pilot study, two new assessment methods were developed: the first is ensemble empirical mode decomposition based reflection index (EEMD-RI) while the second is based on the phase shift between ECG and BP on cardiac oscillation. Both methods utilise the EEMD algorithm which is suitable for nonlinear and nonstationary systems. These methods were used to investigate the properties of arterial stiffness and systemic resistance for a pig's cardiovascular system via ECG and blood pressure (BP). This experiment simulated a sequence of continuous changes of blood pressure arising from steady condition to high blood pressure by clamping the artery and an inverse by relaxing the artery. As a hypothesis, the arterial stiffness and systemic resistance should vary with the blood pressure due to clamping and relaxing the artery. The results show statistically significant correlations between BP, EEMD-based RI, and the phase shift between ECG and BP on cardiac oscillation. The two assessments results demonstrate the merits of the EEMD for signal analysis.

Yeh, Jia-Rong; Lin, Tzu-Yu; Chen, Yun; Sun, Wei-Zen; Abbod, Maysam F.; Shieh, Jiann-Shing

2012-01-01

211

Toxicology of smokeless tobacco: implications for immune, reproductive, and cardiovascular systems.  

PubMed

The popularity of smokeless tobacco (ST), or noncombusted tobacco, usually placed within the mouth to be chewed, sucked, or swallowed, is growing rapidly and its prevalence of use is rising globally, due (in part) to greater convenience, as allowable cigarette smoking areas are rapidly decreasing, and increased social acceptability. Though data are limited, ST usage has been directly linked to a number of adverse health outcomes. The potential role that immune dysfunction, including dysregulation of immune cells and their components, may play in the progression of these adverse health outcomes is only just beginning to emerge. Evidence suggesting reproductive outcomes, such as perinatal mortality, preterm birth, and reduced sperm viability, also exists in conjunction with ST use. Cardiovascular health may also be impacted by ST use, resulting in increased blood pressure and endothelial dysfunction, both of which may potentially lead to cardiovascular diseases. This review describes the toxicological implications associated with ST use, with emphasis on immune, reproductive, and cardiovascular outcomes. Epidemiological studies are discussed with respect to experimental studies to help develop the relationship between ST and disease pathology. This review also summarizes the gaps in ST knowledge and potential future directions that are needed to more fully delineate the complex systems driving the adverse health outcomes associated with its use. PMID:22852812

Willis, Daniel; Popovech, Mary; Gany, Francesca; Zelikoff, Judith

2012-01-01

212

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; Ilhan, Tuncay; Yilmaz, Mustafa Sertac; Erdost, Hatice; Yalcin, Murat

2014-08-01

213

Cardiovascular diseases and molecular variants of the renin-angiotensin system components in Slovak population.  

PubMed

Cardiovascular diseases associated with molecular variants of individual components of renin-angiotensin system are reported to constitute inherited predisposition in humans. Molecular variant frequencies are race- and population-dependent. We examined frequencies of the M235T variant of angiotensinogen gene and I/D polymorphism of gene for angiotensin-converting enzyme in Slovak population: in hypertensive patients, coronary heart disease (CHD), dilated cardiomyopathy (DCM) and myocardial infarction (MI) patients compared to healthy subjects. Frequency of M235T was significantly increased in hypertensive, CHD and DCM patients compared to controls (0.48 and 0.50 vs. 0.40, p < 0.001). Significant increase in D allele frequency compared to controls was observed in the group of patients after MI (0.58 vs. 0.50, p < 0.001), CHD (0.59 vs. 0.50, p < 0.001) and DCM (0.60 vs. 0.50, p < 0.001). These results correlate with other Caucasian populations. In Slovak population, M235T is associated with increased blood pressure and D allele of ACE gene is associated with MI, chronic CHD and DCM, rather than with hypertension. Our results suggest that in Slovak population, D alelle and M235T variant represent a risk factor for several cardiovascular diseases and these polymorphisms might have a cumulative effect on development of cardiovascular diseases. PMID:17579251

Jurkovicova, D; Sedlakova, B; Riecansky, I; Goncalvesova, E; Penesova, A; Kvetnansky, R; Krizanova, O

2007-03-01

214

It is time to reconsider the cardiovascular protection afforded by RAAS blockade -- overview of RAAS systems.  

PubMed

More than a century has passed since the renin-angiotensin-aldosterone system (RAAS) was discovered in 1897. Both circulatory and tissue RAAS have been found to be essential for regulation of the functions of the whole body, organs, tissues and cells. There is no doubt that the RAAS plays fundamental physiological roles in maintaining homeostasis, but it can also contribute to organ pathophysiology and tissue damages in some situations. Today, the usefulness of RAAS blockade is well-established in the management of a variety of cardiovascular disorders worldwide. However, the latest findings in this field are still providing us with new and unexpected insights into the pathophysiology of cardiovascular diseases. Such developments include dual blockade therapy with angiotensin I converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs), and a new class of RAAS blockers, renin inhibitors. These give us the opportunity to revisit the basic principles of the RAAS and reconsider the strategies of RAAS blockade for cardiovascular protection. PMID:22147138

Tsukamoto, Osamu; Kitakaze, Masafumi

2013-04-01

215

Significance of the development of a cardiovascular disease surveillance and reporting system in India.  

PubMed

Cardiovascular disease (CVD) is the single largest cause of global morbidity and mortality and is the leading cause of death in the Indian subcontinent projected to contribute to deaths expected to double by 2015. The social and economic impact of these staggering projections highlight the need for a centralized effort to monitor and evaluate behavioral and physiological risk factors for CVD. Limited evidence on existing surveillance systems suggest that the key to an effective monitoring and evaluation (M and E) program for CVD surveillance in India relies upon the World Health Organization's STEP-wise model. Key recommendations for the Ministry of Health include the development of a national CVD surveillance program with expertise and a quality-improvement mechanism to receive continuous input from similar surveillance programs in likeminded countries. Structure of the surveillance system would include; (1) the development of process measures for CVD risk factor' based surveillance M and E systems for early detection of CVD at the local-level, (2) the development of trigger based data reporting responsibilities to State-based monitoring teams including incentives for accuracy in data reporting and the use of data-driven evidence to target risk specific intervention and prevention on Central Government monitoring teams with reporting feedback to the State and local-levels and (3) the creation of health policy to require the use of data to target risk specific prevention for intervention and developing local technical capacity. Such a system would provide significant cost and social benefits, presenting an evidence based data driven cost-effective business case for scale-up and potential use in areas comprising similar demographics. Future research should focus on the inclusion of a systematic critique of the reported data for the challenges to surveillance systems in India and the examination of the effect of an incentivized reporting system on the states. Further inquiry into the types of reporting and lessons from other countries' surveillance programs with alternative strategies to a national approach should address potential imitations at the ground or peripheral levels. PMID:24347902

Coelho, Ken Russell

2013-09-01

216

Recent insights and therapeutic perspectives of angiotensin-(1-9) in the cardiovascular system.  

PubMed

Chronic RAS (renin-angiotensin system) activation by both AngII (angiotensin II) and aldosterone leads to hypertension and perpetuates a cascade of pro-hypertrophic, pro-inflammatory, pro-thrombotic and atherogenic effects associated with cardiovascular damage. In 2000, a new pathway consisting of ACE2 (angiotensin-converting enzyme2), Ang-(1-9) [angiotensin-(1-9)], Ang-(1-7) [angiotensin-(1-7)] and the Mas receptor was discovered. Activation of this novel pathway stimulates vasodilation, anti-hypertrophy and anti-hyperplasia. For some time, studies have focused mainly on ACE2, Ang-(1-7) and the Mas receptor, and their biological properties that counterbalance the ACE/AngII/AT1R (angiotensin type 1 receptor) axis. No previous information about Ang-(1-9) suggested that this peptide had biological properties. However, recent data suggest that Ang-(1-9) protects the heart and blood vessels (and possibly the kidney) from adverse cardiovascular remodelling in patients with hypertension and/or heart failure. These beneficial effects are not modified by the Mas receptor antagonist A779 [an Ang-(1-7) receptor blocker], but they are abolished by the AT2R (angiotensin type 2 receptor) antagonist PD123319. Current information suggests that the beneficial effects of Ang-(1-9) are mediated via the AT2R. In the present review, we summarize the biological effects of the novel vasoactive peptide Ang-(1-9), providing new evidence of its cardiovascular-protective activity. We also discuss the potential mechanism by which this peptide prevents and ameliorates the cardiovascular damage induced by RAS activation. PMID:25029123

Ocaranza, Maria Paz; Michea, Luis; Chiong, Mario; Lagos, Carlos F; Lavandero, Sergio; Jalil, Jorge E

2014-11-01

217

Ventilatory and cardiovascular responses to hypoxia and hypercapnia in multiple system atrophy  

PubMed Central

Objective To determine whether ventilatory and cardiovascular responses to hypercapnia and hypoxia during wakefulness are systematically impaired in multiple system atrophy (MSA). Method Case-control study on minute ventilation, blood pressure, and heart rate responses to hypercapnia and hypoxia in 16 patients with probable MSA and 14 age-matched controls during wakefulness. Hypercapnia was induced by a rebreathing technique and limited to an expiratory partial pressure of CO2 (Pet CO2) ? 65mmHg. Hypoxia was induced by a step-wise increase in inspired nitrogen partial pressure and limited to a minimal oxygen saturation (SaO2) of 80%. Ventilatory responses were assessed as slopes of the regression line relating minute ventilation to changes in SaO2 and PetCO2, respectively. Results Ventilatory responses to hypercapnia and hypoxia where preserved in MSA patients, despite the presence of severe autonomic failure. In contrast, cardiovascular responses to these stimuli were impaired in MSA. Compared to controls, hypercapnia elicited less robust increase in arterial pressure (p < 0.001) and hypoxia elicited a depressor rather than the normal pressor responses (p <0.001). Conclusion Ventilatory responses to hypercapnia and hypoxia during wakefulness may be preserved in MSA patients despite the presence of autonomic failure and impaired cardiovascular responses to these stimuli. This suggests that a critical number of chemosensitive medullary neurons must be lost before development of impaired automatic ventilation during wakefulness in MSA, whereas earlier loss of medullary sympathoexcitatory neurons may contribute to the impaired cardiovascular responses in these patients.

Lipp, Axel; Schmelzer, James D.; Low, Phillip A.; Johnson, Bruce D.; Benarroch, Eduardo E.

2010-01-01

218

Cardiovascular risk  

PubMed Central

Cardiovascular disease is a major, growing, worldwide problem. It is important that individuals at risk of developing cardiovascular disease can be effectively identified and appropriately stratified according to risk. This review examines what we understand by the term risk, traditional and novel risk factors, clinical scoring systems, and the use of risk for informing prescribing decisions. Many different cardiovascular risk factors have been identified. Established, traditional factors such as ageing are powerful predictors of adverse outcome, and in the case of hypertension and dyslipidaemia are the major targets for therapeutic intervention. Numerous novel biomarkers have also been described, such as inflammatory and genetic markers. These have yet to be shown to be of value in improving risk prediction, but may represent potential therapeutic targets and facilitate more targeted use of existing therapies. Risk factors have been incorporated into several cardiovascular disease prediction algorithms, such as the Framingham equation, SCORE and QRISK. These have relatively poor predictive power, and uncertainties remain with regards to aspects such as choice of equation, different risk thresholds and the roles of relative risk, lifetime risk and reversible factors in identifying and treating at-risk individuals. Nonetheless, such scores provide objective and transparent means of quantifying risk and their integration into therapeutic guidelines enables equitable and cost-effective distribution of health service resources and improves the consistency and quality of clinical decision making.

Payne, Rupert A

2012-01-01

219

Matching index of refraction using a diethyl phthalate/ethanol solution for in vitro cardiovascular models  

NASA Astrophysics Data System (ADS)

Experiments studying cardiovascular geometries require a working fluid that matches the high index of refraction of glass and silicone, has a low viscosity, and is safe and inexpensive. A good candidate working fluid is diethyl phthalate (DEP), diluted with ethanol. Measurements were made of index of refraction and viscosity of varied dilutions at a range of temperatures, and empirical models are proposed. Material compatibility tests showed that only specific formulations of ABS, acrylic, vinyl and PVC are compatible. A silicone elastomer additionally tested negative for change in compliance with DEP exposure.

Miller, P.; Danielson, K.; Moody, G.; Slifka, A.; Drexler, E.; Hertzberg, J.

2006-09-01

220

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.

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

221

A framework for modeling and visualizing cardiovascular deformation under normal and altered circulatory conditions.  

PubMed

The aim of this paper is to model and visualize cardiovascular deformations in order to better understand vascular movements inside the lung and heart caused by abnormal cardiac conditions. The modeling was performed in two steps: first step involved modeling the cardiac output taking into account of the heart rate and preload blood volume, contractility and systematic vascular resistance. The second step involved deforming a 3D cine cardiac gated Magnetic Resonance Volume to the corresponding cardiac output. Cardiac-gated MR imaging of 4 healthy volunteers were acquired. For each volunteer, a total of 24 short-axis and 18 radial planar views were acquired on a 1.5 T MR scanner during a series of 12-15 second breath-hold maneuvers. A 3D multi-resolution optical flow deformable image registration algorithm was used to quantify the volumetric cardiovascular displacements for known cardiac outputs. Results show that a real-time visualization of the vascular deformations inside both the lung as well as the heart can be seen for different cardiac outputs representing normal and abnormal cardiac conditions. PMID:24732540

Santhanam, Anand; Benharash, Peyman; Frank, Paul; White, Benjamin; Min, Yugang; Ennis, Daniel; Kupelian, Patrick; Dutson, Erik

2014-01-01

222

Absence of cardiovascular manifestations in a haploinsufficient Tgfbr1 mouse model.  

PubMed

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

223

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.

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

224

Models to predict cardiovascular risk: comparison of CART, multilayer perceptron and logistic regression.  

PubMed Central

The estimate of a multivariate risk is now required in guidelines for cardiovascular prevention. Limitations of existing statistical risk models lead to explore machine-learning methods. This study evaluates the implementation and performance of a decision tree (CART) and a multilayer perceptron (MLP) to predict cardiovascular risk from real data. The study population was randomly splitted in a learning set (n = 10,296) and a test set (n = 5,148). CART and the MLP were implemented at their best performance on the learning set and applied on the test set and compared to a logistic model. Implementation, explicative and discriminative performance criteria are considered, based on ROC analysis. Areas under ROC curves and their 95% confidence interval are 0.78 (0.75-0.81), 0.78 (0.75-0.80) and 0.76 (0.73-0.79) respectively for logistic regression, MLP and CART. Given their implementation and explicative characteristics, these methods can complement existing statistical models and contribute to the interpretation of risk.

Colombet, I.; Ruelland, A.; Chatellier, G.; Gueyffier, F.; Degoulet, P.; Jaulent, M. C.

2000-01-01

225

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.

CAPORALI, ANDREA; EMANUELI, COSTANZA

2010-01-01

226

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

227

The circadian organization of the cardiovascular system in health and disease.  

PubMed

In normal conditions, the temporal organization of blood pressure (BP) is mainly controlled by neuroendocrine mechanisms. Above all, the monoaminergic systems (including variations in activity of the autonomous nervous system, and in secretion of biogenic amines) appear to integrate the major driving factors of temporal variability, but evidence is available also for a role of the hypothalamic-pituitary-adrenal, hypothalamic-pituitary-thyroid, opioid, renin-angiotensin-aldosterone, and endothelial systems, as well as other vasoactive peptides. Many hormones with established actions on the cardiovascular system (arginine vasopressin, vasoactive intestinal peptide, melatonin, somatotropin, insulin, steroids, serotonin, CRF, ACTH, TRH, endogenous opioids, and prostaglandin E2) are also involved in sleep induction or arousal, which in turn affects BP regulation. Hence, physical, mental, and pathological stimuli which may drive activation or inhibition of these neuroendocrine effectors of biological rhythmicity, may also interfere with the temporal BP structure. On the other hand, the immediate adaptation of the exogenous components of BP rhythms to the demands of the environment are modulated by the circadian-time-dependent responsiveness of the biological oscillators and their neuroendocrine effectors. These notions may contribute to a better understanding of the pathophysiology and therapeutics of hypertension, myocardial ischemia and infarction, cardiac arrhythmias and all kind of acute cardiovascular accidents. For instance, the normal temporal balance between external stimuli and neurohumoral influences with endogenous rhythmicity is preserved in uncomplicated, essential hypertension, whereas it is frequently lost in complicated and secondary forms of hypertension where gross alterations are found in the circadian profile of BP. When all the gates of the critical physiologic functions are aligned at the same time, the susceptibility, and thus risk, of adverse events becomes extremely high, even in the presence of minor environmental stimuli that could be usually harmless, and circadian rhythms of cardiovascular events are observed. This implies that one cannot afford to miss what happens during day but also night. Moreover, the requirement for preventive and therapeutic interventions varies predictably during the 24 h, suggesting that the delivery of protective or preventive medications should be synchronized in time in proportion to need, as determined by established rhythmic patterns in cardiovascular function as well as risk, in a manner that will avert or minimize their undesired side effects. PMID:24851400

Portaluppi, Francesco

2014-05-01

228

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

PubMed

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

2012-08-01

229

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.

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

2012-01-01

230

Hydrogen sulphide: biopharmacological roles in the cardiovascular system and pharmaceutical perspectives.  

PubMed

Hydrogen sulphide (H(2)S) is now viewed as an important endogenous gasotransmitter, which exhibits many beneficial effects on the cardiovascular system. H(2)S is biosynthesized in mammalian tissues by both non-enzymatic processes and several enzymatic pathways ensured by cystathionine-?-synthase and cystathionine-?-lyase. H(2)S is endowed with the antioxidant properties of inorganic and organic sulphites, being a scavenger of reactive oxygen species. Furthermore, H(2)S triggers other important effects and the activation of ATP-sensitive potassium channels (KATP) accounts for its vasorelaxing and cardioprotective effects. H(2)S also inhibits smooth muscle proliferation and platelet aggregation. Conversely, the impairment of H(2)S contributes to the pathogenesis of hypertension and is involved in cardiovascular complications associated with diabetes mellitus. There is also evidence of a link between H(2)S and endothelial nitric oxide (NO). Recent observations indicate a possible pathogenic link between deficiencies of H(2)S activity and the progress of endothelial dysfunction. These biological aspects of endogenous H(2)S led to consider this mediator as "the new NO" and to evaluate new attractive opportunities to develop innovative classes of drugs. In this review, the main roles played by H(2)S in the cardiovascular system and the first examples of H(2)S-donor drugs are discussed. Some hybrid drugs are also addressed in this review. In such compounds opportune H(2)S-releasing moieties are conjugated to well-known drugs to improve their pharmacodynamic profile or to reduce the potential for adverse effects. PMID:22680638

Martelli, A; Testai, L; Marino, A; Breschi, M C; Da Settimo, F; Calderone, V

2012-01-01

231

The peripheral-type benzodiazepine receptor and the cardiovascular system. Implications for drug development.  

PubMed

Peripheral-type benzodiazepine receptors (PBRs) are abundant in the cardiovascular system. In the cardiovascular lumen, PBRs are present in platelets, erythrocytes, lymphocytes, and mononuclear cells. In the walls of the cardiovascular system, PBR can be found in the endothelium, the striated cardiac muscle, the vascular smooth muscles, and the mast cells. The subcellular location of PBR is primarily in mitochondria. The PBR complex includes the isoquinoline binding protein (IBP), voltage-dependent anion channel (VDAC), and adenine nucleotide transporter (ANT). Putative endogenous ligands for PBR include protoporphyrin IX, diazepam binding inhibitor (DBI), triakontatetraneuropeptide (TTN), and phospholipase A2 (PLA2). Classical synthetic ligands for PBR are the isoquinoline 1-(2-chlorophenyl)-N-methyl-N-(1-methyl-propyl)-3-isoquinolinecarboxamide (PK 11195) and the benzodiazepine 7-chloro-5-(4-chlorophenyl)-1,3-dihydro-1-methyl-2H-1,4-benzodiazepin-2-one (Ro5 4864). Novel PBR ligands include N,N-di-n-hexyl 2-(4-fluorophenyl)indole-3-acetamide (FGIN-1-27) and 7-chloro-N,N,5-trimethyl-4-oxo-3-phenyl-3,5-dihydro-4H-pyridazino[4,5-b]indole-1-acetamide (SSR180575), both possessing steroidogenic properties, but while FGIN-1-27 is pro-apoptotic, SSR180575 is anti-apoptotic. Putative PBR functions include regulation of steroidogenesis, apoptosis, cell proliferation, the mitochondrial membrane potential, the mitochondrial respiratory chain, voltage-dependent calcium channels, responses to stress, and microglial activation. PBRs in blood vessel walls appear to take part in responses to trauma such as ischemia. The irreversible PBR antagonist, SSR180575, was found to reduce damage correlated with ischemia. Stress, anxiety disorders, and neurological disorders, as well as their treatment, can affect PBR levels in blood cells. PBRs in blood cells appear to play roles in several aspects of the immune response, such as phagocytosis and the secretion of interleukin-2, interleukin-3, and immunoglobulin A (IgA). Thus, alterations in PBR density in blood cells may have immunological consequences in the affected person. In conclusion, PBR in the cardiovascular system may represent a new target for drug development. PMID:16337685

Veenman, Leo; Gavish, Moshe

2006-06-01

232

High sensitivity C-reactive protein, disease activity and cardiovascular risk factors in systemic lupus erythematosus  

PubMed Central

Objectives To study the level of high-sensitivity C-reactive protein (hsCRP) and its relationship with disease activity, damage and cardiovascular risk factors in patients with systemic lupus erythematosus (SLE). Method Consecutive patients who fulfilled ?4 ACR criteria for SLE but did not have concurrent infection were recruited. Blood was assayed for hsCRP and disease activity, organ damage of SLE and cardiovascular risk factors were assessed. Linear regression was performed for the relationship among hsCRP, SLE activity, damage and cardiovascular risk factors. Results 289 patients were studied (94% women; age 39.0±13.1 years; SLE duration 7.8±6.7 years). The mean SLEDAI score was 4.9±5.6 and clinically active SLE was present in 122(42%) patients. The mean hsCRP level was 4.87±12.7mg/L, and 28(23%) patients with active SLE had undetectable hsCRP (<0.3mg/L). Linear regression revealed a significant correlation between hsCRP and musculoskeletal (Beta=0.21), hematological (Beta=0.19), serosal (Beta=0.46) and clinical SLEDAI score (Beta=0.24), adjusting for age, sex, body mass index, creatinine and the use of various medications (p<0.005 in all). Levels of hsCRP correlated significantly with anti-dsDNA titer (Beta=0.33;p<0.001) but not with complement C3 (Beta=0.07;p=0.26). Significantly more patients with hsCRP >3.0mg/L were men and chronic smokers, and had diabetes mellitus, higher atherogenic index and history of arterial thrombosis. hsCRP levels correlated significantly with pulmonary and endocrine damage score. Conclusions hsCRP is detectable in 77% of SLE patients with clinically active disease and correlates with SLEDAI scores, particularly serositis and in the musculoskeletal and hematological systems. Elevated hsCRP in SLE is associated with certain cardiovascular risk factors and history of arterial thromboembolism.

Mok, CC; Birmingham, Daniel J.; Ho, Ling Yin; Hebert, Lee A; Rovin, Brad H

2012-01-01

233

Energy harvesting from the cardiovascular system, or how to get a little help from yourself.  

PubMed

Human energy harvesting is envisioned as a remedy to the weight, the size, and the poor energy density of primary batteries in medical implants. The first implant to have necessarily raised the idea of a biological power supply was the pacemaker in the early 1960s. So far, review articles on human energy harvesting have been rather unspecific and no tribute has been given to the early role of the pacemaker and the cardiovascular system in triggering research in the field. The purpose of the present article is to provide an up-to-date review of research efforts targeting the cardiovascular system as an alternative energy source for active medical implants. To this end, a chronological survey of the last 14 most influential publications is proposed. They include experimental and/or theoretical studies based on electromagnetic, piezoelectric, or electrostatic transducers harnessing various forms of energy, such as heart motion, pressure gradients, and blood flow. Technical feasibility does not imply clinical applicability: although most of the reported devices were shown to harvest an interesting amount of energy from a physiological environment, none of them were tested in vivo for a longer period of time. PMID:23949656

Pfenniger, Alois; Jonsson, Magnus; Zurbuchen, Adrian; Koch, Volker M; Vogel, Rolf

2013-11-01

234

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

235

Milan PM1 induces adverse effects on mice lungs and cardiovascular system.  

PubMed

Recent studies have suggested a link between inhaled particulate matter (PM) exposure and increased mortality and morbidity associated with cardiorespiratory diseases. Since the response to PM1 has not yet been deeply investigated, its impact on mice lungs and cardiovascular system is here examined. A repeated exposure to Milan PM1 was performed on BALB/c mice. The bronchoalveolar lavage fluid (BALf) and the lung parenchyma were screened for markers of inflammation (cell counts, tumor necrosis factor-? (TNF-?); macrophage inflammatory protein-2 (MIP-2); heme oxygenase-1 (HO-1); nuclear factor kappa-light-chain-enhancer of activated B cells p50 subunit (NF?B-p50); inducible nitric oxide synthetase (iNOS); endothelial-selectin (E-selectin)), cytotoxicity (lactate dehydrogenase (LDH); alkaline phosphatase (ALP); heat shock protein 70 (Hsp70); caspase-8-p18), and a putative pro-carcinogenic marker (cytochrome 1B1 (Cyp1B1)). Heart tissue was tested for HO-1, caspase-8-p18, NF?B-p50, iNOS, E-selectin, and myeloperoxidase (MPO); plasma was screened for markers of platelet activation and clot formation (soluble platelet-selectin (sP-selectin); fibrinogen; plasminogen activator inhibitor 1 (PAI-1)). PM1 triggers inflammation and cytotoxicity in lungs. A similar cytotoxic effect was observed on heart tissues, while plasma analyses suggest blood-endothelium interface activation. These data highlight the importance of lung inflammation in mediating adverse cardiovascular events following increase in ambient PM1 levels, providing evidences of a positive correlation between PM1 exposure and cardiovascular morbidity. PMID:23509745

Farina, Francesca; Sancini, Giulio; Longhin, Eleonora; Mantecca, Paride; Camatini, Marina; Palestini, Paola

2013-01-01

236

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.

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

2012-01-01

237

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

NASA Astrophysics Data System (ADS)

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 used to display static/dynamic radiographic images, or video sequences, ECG and other text information. The display program is designed with functions of image processing, multimedia data manipulation and visualization. In addition, the workstation also integrates with a real time tele-consultation component for the necessary consultation between cardiologists and remote radiologists equipped with a tele-consultation workstation. Finally, we discuss the system clinical performance and the applications.

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

2000-04-01

238

[Characterization of cardiovascular system function in children from the Issyk-Kul Rregion].  

PubMed

The age-specific features of the cardiovascular system in a child and the pattern of adaptive responses to the long-term impact the mountain-and-maritime climate of the Issyk-Kul Region. All the children were found to have bradycardia (43-61 beats per min), which corresponds to the parasympathetic predominance of their nervous system. They also showed a short pulse recovery (60 seconds), unlike the children of the plains and a statistically significant pulse rate reduction at rest minute 5 (p < 0.05) as compared with the base-line level. In the settlement of Kadji-Sai, there was a decrease in all functional parameters: pressure, the time of a response to light and sound stimuli. It was ascertained that the following features were characteristic for mountain dwellers: bradycardia associated with the predominance of the parasympathetic nervous system and the tendency towards lowered systolic pressure without a significant change in diastolic pressure. PMID:16022257

Sharshenova, A A; Mazhikova, E Dzh

2005-01-01

239

Cardiovascular and hormonal (aldosterone) responses in a rat model which mimics responses to weightlessness  

NASA Technical Reports Server (NTRS)

Cardiovascular responses and fluid/electrolyte shifts seen during spaceflight have been attributed to cephalad redistribution of vascular fluid. The antiorthostatic (AO) rat (suspended, head-down tilt of 15-20 deg) is used to model these responses. This study documents that elevated blood pressures in AO rats are sustained for periods of up to seven days, compared with presuspension values. Increased blood pressures in AO rats suggests a specific response to AO positioning, potentially relatable to a cephalad fluid shift. To assess a role for hormonal regulation of sodium excretion, serum aldosterone levels were measured. Circulating aldosterone concentrations were seen to increase approximately 100 percent during seven days of AO suspension, concurrently with a pronounced natriuresis. These results suggest that aldosterone may not be involved in the long term regulation of increased Na(+) excretion in AO animals. These studies continue to show the usefulness of models for the development of animal protocols for space flight.

Musacchia, X. J.; Steffen, J. M.

1984-01-01

240

Development of Predictive Models for Long-Term Cardiovascular Risk Associated With Systolic and Diastolic Blood Pressure  

Microsoft Academic Search

Most existing risk prediction models have not considered the joint contribution of systolic and diastolic blood pressure to cardiovascular risk, and some suggest that there are thresholds below which further reductions of blood pressure yield no additional benefit. We developed multivariate risk prediction models that quantify the risk associated with both systolic and diastolic blood pressure and that can be

Robert J. Glynn; Gilbert J. L'Italien; Howard D. Sesso; Elizabeth A. Jackson; Julie E. Buring

241

Implicit and Explicit Model-Based Signal Processing for the Analysis of Short-Term Cardiovascular Interactions  

Microsoft Academic Search

The paper stresses the importance of model-based signal processing in the analysis of the cardiovascular regulation mechanisms. It is remarked that even traditional signal processing implicitly assumes a model and interprets data according to it. Therefore, traditional signal processing is here referred to as implicit model-based signal processing in contrast with explicit model-based signal processing directly stemming from modeling considerations.

ALBERTO PORTA; GIUSEPPE BASELLI; SERGIO CERUTTI

2006-01-01

242

Comparison of competing risks models based on cumulative incidence function in analyzing time to cardiovascular diseases  

PubMed Central

BACKGROUND Competing risks arise when the subject is exposed to more than one cause of failure. Data consists of the time that the subject failed and an indicator of which risk caused the subject to fail. METHODS With three approaches consisting of Fine and Gray, binomial, and pseudo-value, all of which are directly based on cumulative incidence function, cardiovascular disease data of the Isfahan Cohort Study were analyzed. Validity of proportionality assumption for these approaches is the basis for selecting appropriate models. Such as for the Fine and Gray model, establishing proportionality assumption is necessary. In the binomial approach, a parametric, non-parametric, or semi-parametric model was offered according to validity of assumption. However, pseudo-value approaches do not need to establish proportionality. RESULTS Following fitting the models to data, slight differences in parameters and variances estimates were seen among models. This showed that semi-parametric multiplicative model and the two models based on pseudo-value approach could be used for fitting this kind of data. CONCLUSION We would recommend considering the use of competing risk models instead of normal survival methods when subjects are exposed to more than one cause of failure.

Dianatkhah, Minoo; Rahgozar, Mehdi; Talaei, Mohammad; Karimloua, Masoud; Sadeghi, Masoumeh; Oveisgharan, Shahram; Sarrafzadegan, Nizal

2014-01-01

243

Sent to Destroy: The Ubiquitin Proteasome System Regulates Cell Signaling and Protein Quality Control in Cardiovascular Development and Disease  

PubMed Central

The ubiquitin proteasome system (UPS) plays a crucial role in biological processes integral to the development of the cardiovascular system and cardiovascular diseases. The UPS prototypically recognizes specific protein substrates and places polyubiquitin chains on them for subsequent destruction by the proteasome. This system is in place to degrade not only misfolded and damaged proteins, but is essential also in regulating a host of cell signaling pathways involved in proliferation, adaptation to stress, regulation of cell size, and cell death. During the development of the cardiovascular system, the UPS regulates cell signaling by modifying transcription factors, receptors, and structural proteins. Later, in the event of cardiovascular diseases as diverse as atherosclerosis, cardiac hypertrophy, and ischemia reperfusion injury, ubiquitin ligases and the proteasome are implicated in protecting and exacerbating clinical outcomes. However, when misfolded and damaged proteins are ubiquitinated by the UPS, their destruction by the proteasome is not always possible due to their aggregated confirmations. Recent studies have discovered how these ubiquitinated misfolded proteins can be destroyed by alternative “specific” mechanisms. The cytosolic receptors p62, NBR, and HDAC6 recognize aggregated ubiquitinated proteins and target them for autophagy in the process of “selective autophagy”. Even the ubiquitination of multiple proteins within whole organelles that drive the more general macro-autophagy may be due, in part, to similar ubiquitin-driven mechanisms. In summary, the cross-talk between the UPS and autophagy highlight the pivotal and diverse roles the UPS plays in maintaining protein quality control and regulating cardiovascular development and disease.

Willis, Monte S.; Townley-Tilson, W.H. Davin; Kang, Eunice Y.; Homeister, Jonathon W.; Patterson, Cam

2010-01-01

244

Abnormal Sleep-Cardiovascular System Interaction in Narcolepsy with Cataplexy: Effects of Hypocretin Deficiency in Humans  

PubMed Central

Study Objective: Narcolepsy with cataplexy (NC) is associated with loss of hypocretin neurons in the lateral hypothalamus involved in the circadian timing of sleep and wakefulness, and many biologic functions including autonomic control. The authors investigated whether chronic lack of hypocretin signaling alters cardiovascular control during sleep in humans. Design: Comparison of 24-hr circadian rhythms, day-night, time- and state-dependent changes of blood pressure (BP) and heart rate (HR) in drug-free patients with NC and control subjects. Setting: University hospital. Patients or Participants: Ten drug-free patients with NC (9 men, 1 woman) and 12 control subjects (9 men, 3 women). Interventions: N/A. Measurements and Results: Daytime BP was comparable in patients with NC and controls, but patients with NC displayed a nighttime nondipping BP pattern. The 24-hr circadian rhythmicity of BP and HR was normal in both groups. Systolic BP during nighttime rapid eye movement sleep was significantly increased in the NC group. The 24-hr HR was significantly higher in the NC group but the day-night and state-dependent HR modulations were intact. The nighttime BP pattern coupled in the NC group with increased sleep fragmentation and a higher prevalence of arousals, periodic limb movements in sleep (PLMS), and PLMS arousals. In an analysis of the sleep/cardiovascular interaction in the periods after sleep onset and preceding morning awakening, only PLMS were consistently associated with the blunted nighttime decrease in BP in the NC group. Conclusions: Hypocretin deficiency in humans may couple with an altered nighttime BP regulation that can be associated with an increased cardiovascular risk. This finding may be the result not only of the hypocretinergic deficiency per se but also of the altered sleep/wake regulation characterizing NC. Citation: Grimaldi D; Calandra-Buonaura G; Provini F; Agati P; Pierangeli G; Franceschini C; Barletta G; Plazzi G; Montagna P; Cortelli P. Abnormal sleep-cardiovascular system interaction in narcolepsy with cataplexy: effects of hypocretin deficiency in humans. SLEEP 2012;35(4):519-528.

Grimaldi, Daniela; Calandra-Buonaura, Giovanna; Provini, Federica; Agati, Patrizia; Pierangeli, Giulia; Franceschini, Christian; Barletta, Giorgio; Plazzi, Giuseppe; Montagna, Pasquale; Cortelli, Pietro

2012-01-01

245

Comparison of Prediction Model for Cardiovascular Autonomic Dysfunction Using Artificial Neural Network and Logistic Regression Analysis  

PubMed Central

Background This study aimed to develop the artificial neural network (ANN) and multivariable logistic regression (LR) analyses for prediction modeling of cardiovascular autonomic (CA) dysfunction in the general population, and compare the prediction models using the two approaches. Methods and Materials We analyzed a previous dataset based on a Chinese population sample consisting of 2,092 individuals aged 30–80 years. The prediction models were derived from an exploratory set using ANN and LR analysis, and were tested in the validation set. Performances of these prediction models were then compared. Results Univariate analysis indicated that 14 risk factors showed statistically significant association with the prevalence of CA dysfunction (P<0.05). The mean area under the receiver-operating curve was 0.758 (95% CI 0.724–0.793) for LR and 0.762 (95% CI 0.732–0.793) for ANN analysis, but noninferiority result was found (P<0.001). The similar results were found in comparisons of sensitivity, specificity, and predictive values in the prediction models between the LR and ANN analyses. Conclusion The prediction models for CA dysfunction were developed using ANN and LR. ANN and LR are two effective tools for developing prediction models based on our dataset.

Zeng, Fangfang; Li, Zhongtao; Yu, Xiaoling; Zhou, Linuo

2013-01-01

246

Neutral endopeptidase inhibition and the natriuretic peptide system: an evolving strategy in cardiovascular therapeutics  

PubMed Central

Hypertension and heart failure (HF) are common diseases that, despite advances in medical therapy, continue to be associated with high morbidity and mortality. Therefore, innovative therapeutic strategies are needed. Inhibition of the neutral endopeptidase (NEPinh) had been investigated as a potential novel therapeutic approach because of its ability to increase the plasma concentrations of the natriuretic peptides (NPs). Indeed, the NPs have potent natriuretic and vasodilator properties, inhibit the activity of the renin–angiotensin–aldosterone system, lower sympathetic drive, and have antiproliferative and antihypertrophic effects. Such potentially beneficial effects can be theoretically achieved by the use of NEPinh. However, studies have shown that NEPinh alone does not result in clinically meaningful blood pressure-lowering actions. More recently, NEPinh has been used in combination with other cardiovascular agents, such as angiotensin-converting enzyme inhibitors, and antagonists of the angiotensin receptor. Another future possible combination would be the use of NEPinh with NPs or their newly developed chimeric peptides. This review summarizes the current knowledge of the use and effects of NEPinh alone or in combination with other therapeutic agents for the treatment of human cardiovascular disease such as HF and hypertension.

Mangiafico, Sarah; Costello-Boerrigter, Lisa C.; Andersen, Ingrid A.; Cataliotti, Alessandro; Burnett, John C.

2013-01-01

247

Vascular peroxidase 1: a novel enzyme in promoting oxidative stress in cardiovascular system.  

PubMed

Vascular peroxidase 1 (VPO1) is a recently identified novel family member of peroxidases in cardiovascular system. As an enzyme that is downstream of NADPH oxidases (NOX), VPO1 functions to utilize NOX - derived hydrogen peroxide (H2O2) to produce hypochlorous acid (HOCl), a strong oxidant which is believed to greatly promote oxidative stress. Under multiple conditions, NOX is activated concomitantly with an increase in superoxide anion (O2(.-)) and H2O2 production. The latter is converted to HOCl by VPO1. In this process (O2(.-) ? H2O2 ? HOCl), the oxidant reactivities of reactive oxygen species (ROS) are significantly increased and therefore the oxidative stress is dramatically amplified. Several lines of evidence suggest that the NOX/VPO1 pathway - mediated oxidative stress plays an important role in myocardial ischemia-reperfusion injury, endothelial cell apoptosis and/or smooth muscle cell proliferation. In addition, VPO1 can be secreted into the extracellular space to participate in extracellular matrix formation, suggesting that VPO1 may also play a role in cardiovascular remodeling (such as fibrosis). This function is independent of the peroxidase activity of VPO1. PMID:23357484

Ma, Qi-Lin; Zhang, Guo-Gang; Peng, Jun

2013-07-01

248

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.

Ghandour, Abed; Rajiah, Prabhakar

2014-01-01

249

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

PubMed

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

2014-05-28

250

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.

2013-01-01

251

Differential protection against oxidative stress and nitric oxide overproduction in cardiovascular and pulmonary systems by propofol during endotoxemia  

PubMed Central

Background Both overproduction of nitric oxide (NO) and oxidative injury of cardiovascular and pulmonary systems contribute to fatal cardiovascular depression during endotoxemia. We investigated in the present study the relative contribution of oxidative stress and NO to cardiovascular depression during different stages of endotoxemia, and delineated their roles in cardiovascular protective effects of a commonly used anesthetic propofol during endotoxemia. Methods Experimental endotoxemia was induced by systemic injection of E. coli lipopolysaccharide (LPS, 15 mg/kg) to Sprague-Dawley rats that were maintained under propofol (15 or 30 mg/kg/h, i.v.) anesthesia. Mean systemic arterial pressure (MSAP) and heart rate (HR) were monitored for 6 h after the endotoxin. Tissue level of NO was measured by chemical reduction-linked chemiluminescence and oxidative burst activity was determined using dihydroethidium method. Expression of NO synthase (NOS) was determined by immunoblotting. The Scheffé multiple range test was used for post hoc statistical analysis. Results Systemic injection of LPS (15 mg/kg) induced biphasic decreases in MSAP and HR. In the heart, lung and aorta, an abrupt increase in lipid peroxidation, our experimental index of oxidative tissue injury, was detected in early stage and sustained during late stage cardiovascular depression. LPS injection, on the other hand, induced a gradual increase in tissue nitrite and nitrate levels in the same organs that peaked during late stage endotoxemia. Propofol infusion (15 or 30 mg/kg/h, i.v.) significantly attenuated lipid peroxidation in the heart, lung and aorta during early and late stage endotoxemia. High dose (30 mg/kg/h, i.v.) propofol also reversed the LPS-induced inducible NO synthase (iNOS) upregulation and NO production in the aorta, alongside a significant amelioration of late stage cardiovascular depression and increase in survival time during endotoxemia. Conclusion Together these results suggest that oxidative injury and NO may play a differential role in LPS-induced cardiovascular depression. Oxidative tissue injury is associated with both early and late stage; whereas NO is engaged primarily in late stage cardiovascular depression. Moreover, propofol anesthesia may protect against fatal cardiovascular depression during endotoxemia by attenuating the late stage NO surge in the aorta, possibly via inhibition of iNOS upregulation by the endotoxin.

Liu, Yen-Chin; Chang, Alice YW; Tsai, Yu-Chuan; Chan, Julie YH

2009-01-01

252

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

253

Severe hypoxia enhances central nervous system and cardiovascular toxicity of bupivacaine in lightly anesthetized pigs.  

PubMed

Toxic systemic reactions to bupivacaine usually involve a number of factors, including hypoxia and acidosis. The objective of this study was to test the hypothesis that cardiovascular and central nervous system responses to bupivacaine overdose are proportional to the severity of hypoxia. The central nervous system and cardiovascular toxicity of bupivacaine was examined in three groups of pigs breathing 30%, 15%, or 10% O2, 70% N2O, and He (FIO2 = 0.15 and 0.1 groups). The 18 2-week-old pigs (6 animals per treatment) were paralyzed with pancuronium and their lungs ventilated mechanically. During the intravenous infusion of bupivacaine 2 mg.kg-1.min-1, four readily identified toxic endpoints (seizures, arrhythmias, isoelectric electroencephalogram, asystole) were observed in all animals, with the exception that 1 pig in the FIO2 = 0.3 group and 1 in the FIO2 = 0.15 group had no arrhythmias. Bupivacaine doses producing seizures, isoelectric EEG, and asystole were significantly less in the FIO2 = 0.1 groups as compared to the other groups. Arrhythmias occurred before seizures in all animals in the FIO2 = 0.1 group but in only 1 of 5 and 2 of 5 animals in the FIO2 = 0.15 and 0.3 groups, respectively. There was no significant difference between the arrhythmic dose of bupivacaine in the FIO2 = 0.3 versus 0.1 animals (8.4 +/- 2.4 vs. 4.0 +/- 1.4 mg.kg-1), but the dose was significantly less in the FIO2 = 0.1 animals than in the FIO2 = 0.15 animals (12.5 +/- 5.6 mg.kg-1). Arterial pH was stable in all three groups during bupivacaine infusion.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1609987

Heavner, J E; Dryden, C F; Sanghani, V; Huemer, G; Bessire, A; Badgwell, J M

1992-07-01

254

Continuous-flow pump model study: the effect on pump performance of pump characteristics and cardiovascular conditions.  

PubMed

This model study evaluates the effect of pump characteristics and cardiovascular data on hemodynamics in atrio-aortic VAD assistance. The model includes a computational circulatory sub-model and an electrical sub-model representing two rotary blood pumps through their pressure-flow characteristics. The first is close to a pressure generator-PG (average flow sensitivity to pressure variations, -0.047 l mmHg(-1)); the second is closer to a flow generator-FG (average flow sensitivity to pressure variations, -0.0097 l mmHg(-1)). Interaction with VAD was achieved by means of two interfaces, behaving as impedance transformers. The model was verified by use of literature data and VAD onset conditions were used as a control for the experiments. Tests compared the two pumps, at constant pump speed, in different ventricular and circulatory conditions: maximum ventricular elastance (0.44-0.9 mmHg cm(-3)), systemic peripheral resistance (781-1200 g cm(-4) s(-1)), ventricular diastolic compliance C p (5-10-50 cm(3) mmHg(-1)), systemic arterial compliance (0.9-1.8 cm(3) mmHg(-1)). Analyzed variables were: arterial and venous pressures, flows, ventricular volume, external work, and surplus hemodynamic energy (SHE). The PG pump generated the highest SHE under almost all conditions, in particular for higher C p (+50 %). PG pump flow is also the most sensitive to E max and C p changes (-26 and -33 %, respectively). The FG pump generally guarantees higher external work reduction (54 %) and flow less dependent on circulatory and ventricular conditions. The results are evidence of the importance of pump speed regulation with changing ventricular conditions. The computational sub-model will be part of a hydro-numerical model, including autonomic controls, designed to test different VADs. PMID:23463355

Ferrari, Gianfranco; Kozarski, Maciej; Fresiello, Libera; Di Molfetta, Arianna; Zieli?ski, Krzysztof; Górczy?ska, Krystyna; Pa?ko, Krzysztof J; Darowski, Marek

2013-06-01

255

Role of altered intestinal microbiota in systemic inflammation and cardiovascular disease in chronic kidney disease.  

PubMed

The normal intestinal microbiota plays a major role in the maintenance of health and disease prevention. In fact, the alteration of the intestinal microbiota has been shown to contribute to the pathogenesis of several pathological conditions, including obesity and insulin resistance, among others. Recent studies have revealed profound alterations of the gut microbial flora in patients and animals with chronic kidney disease (CKD). Alterations in the composition of the microbiome in CKD may contribute to the systemic inflammation and accumulation of gut-derived uremic toxins, which play a central role in the pathogenesis of accelerated cardiovascular disease and numerous other CKD-associated complications. This review is intended to provide a concise description of the potential role of the CKD-associated changes in the gut microbiome and its potential role the pathogenesis of inflammation and uremic toxicity. In addition, the potential efficacy of pre- and pro-biotics in the restoration of the microbiome is briefly described. PMID:24762311

Mafra, Denise; Lobo, Julie C; Barros, Amanda F; Koppe, Laetitia; Vaziri, Nosratola D; Fouque, Denis

2014-03-01

256

CARDIOVASCULAR EFFECTS OF HARPAGOPHYTUM PROCUMBENS DC (PEDALIACEAE) SECONDARY ROOT AQUEOUS EXTRACT IN SOME MAMMALIAN EXPERIMENTAL ANIMAL MODELS  

Microsoft Academic Search

In an attempt to scientifically appraise the 'healing powers' and medicinal value of Harpagophytum procumbens DC root aqueous extract (HPE), and throw some light on the efficacy and safety of the medicinal plant product, the cardiovascular effects of the herb's root aqueous extract (HPE) have been investigated in some mammalian experimental animal models. The results of this laboratory animal study

Ismail M. Mahomed; John A. O. Ojewole

257

Dietary Salt Reduction and Cardiovascular Disease Rates in India: A Mathematical Model  

PubMed Central

Background Reducing salt intake has been proposed to prevent cardiovascular disease in India. We sought to determine whether salt reductions would be beneficial or feasible, given the worry that unrealistically large reductions would be required, worsening iodine deficiency and benefiting only urban subpopulations. Methods and Results Future myocardial infarctions (MI) and strokes in India were predicted with a Markov model simulating men and women aged 40 to 69 in both urban and rural locations, incorporating the risk reduction from lower salt intake. If salt intake does not change, we expect ?8.3 million MIs (95% CI: 6.9–9.6 million), 830,000 strokes (690,000–960,000) and 2.0 million associated deaths (1.5–2.4 million) per year among Indian adults aged 40 to 69 over the next three decades. Reducing intake by 3 g/day over 30 years (?0.1 g/year, 25% reduction) would reduce annual MIs by 350,000 (a 4.6% reduction; 95% CI: 320,000–380,000), strokes by 48,000 (?6.5%; 13,000–83,000) and deaths by 81,000 (?4.9%; 59,000–100,000) among this group. The largest decline in MIs would be among younger urban men, but the greatest number of averted strokes would be among rural men, and nearly one-third of averted strokes and one-fifth of averted MIs would be among rural women. Only under a highly pessimistic scenario would iodine deficiency increase (by <0.0001%, ?1600 persons), since inadequate iodized salt access—not low intake of iodized salt—is the major cause of deficiency and would be unaffected by dietary salt reduction. Conclusions Modest reductions in salt intake could substantially reduce cardiovascular disease throughout India.

Basu, Sanjay; Stuckler, David; Vellakkal, Sukumar; Ebrahim, Shah

2012-01-01

258

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

259

Cardiovascular Deconditioning.  

National Technical Information Service (NTIS)

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...

J. B. Charles J. M. Fritsch-Yelle P. A. Whitson M. L. Wood T. E. Brown G. W. Fortner

1999-01-01

260

[Significance of endogenous sulfur dioxide in the regulation of cardiovascular system].  

PubMed

Since the 1980's nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H(2)S), the endogenous gas molecules produced from metabolic pathway, have been realized as signal molecules to be involved in the regulation of body homeostasis and to play important roles under physiological and pathophysiological conditions. The researches on these endogenous gas signal molecules opened a new avenue in life science. To explore the new member of gasotransmitter family, other endogenous gas molecules which have been regarded as metabolic waste up to date, and their biological regulatory effects have been paid close attention to in the current fields of life science and medicine. Sulfur dioxide (SO(2)) can be produced endogenously from normal metabolism of sulfur-containing amino acids. L-cysteine is oxidized via cysteine dioxygenase to L-cysteinesulfinate, and the latter can proceed through transamination by glutamate oxaloacetate transaminase (GOT) to beta-sulfinyl pyruvate which decomposes spontaneously to pyruvate and SO(2). In mammals, activated neutrophils by oxidative stress can convert H(2)S to sulfite through a reduced form of nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase-dependent process. The authors detected endogenous production of SO(2) in all cardiovascular tissues, including in heart, aorta, pulmonary artery, mesenteric artery, renal artery, tail artery and the plasma SO(2) content. As the key enzyme producing SO(2), GOT mRNA in cardiovascular system was detected and found to be located enriched in endothelial cells and vascular smooth muscle cells near the endothelial layer. When the normal rats were treated with hydroxamate(HDX), a GOT inhibitor, at a dose of 3.7 mg/kg body weight, the blood pressure (BP) went high markedly, the ratio of wall thickness to lumen radius was increased by 18.34%, and smooth muscle cell proliferation was enhanced. The plasma SO(2) level in the rats injected with 125 micromol/kg body weight SO(2) donor was increased to 721.98+/-30.11 micromol/L at the end of 30 seconds, while the blood pressure was decreased to the lowest point 65.0+/- 4.9 mm Hg at the end of 1 minute. The above results showed that endogenous SO(2) might be involved in the maintenance of blood pressure and normal vascular structure. In spontaneous hypertensive rat (SHR) animal model, exogenous supplement of SO(2) donor decreased the BP, the media cross-sectional area, and pressure of the media and the ratio of wall thickness to lumen radius in the SHR. Moreover, the proliferative index of aortic smooth muscle cells was decreased in the SHR treated with SO(2) donor compared with that in SHR. The above data showed that SO(2) could prevent the aortic structural remodeling by inhibiting the proliferation of aortic smooth muscle cells. The authors observed the direct vasorelaxant effects of SO(2) on the aortic ring pre-treated with norepinephrine (NE). SO(2) donor at a concentration of 25-100 micromol/L relaxed the aortic ring temporarily and slightly, but SO(2) donor at a concentration of 1-12 mmol/L induced relaxation of the ring in a concentration-dependent manner. Administration with nicardipine, an L-type calcium channel blocker other than glibenclamide, an ATP sensitive potassium channel (K(ATP) channel) blocker or removal of vascular endothelium could decrease the SO(2)-induced vasorelaxation. In hypoxic pulmonary hypertension animal model, SO(2) donor decreased the mean pulmonary artery pressure and the systolic pulmonary artery pressure (P<0.01), respectively as compared with hypoxic group, and alleviated obviously the hypoxic pulmonary vascular structural remodeling. The percentage of muscularized arteries of small pulmonary vessels was significantly decreased in hypoxia+SO(2) donor-treated rats compared with that of hypoxic rats (P<0.01), while the percentage of non-muscularized vessels was obviously higher in hypoxia with SO(2) donor-treated rats than that of hypoxic rats (P<0.01). Similarly, SO(2) obviously decreased relative media area and relative media thickness of small musculariz

Jin, Hong Fang; DU, Shu Xu; Zhao, Xia; Zhang, Su Qing; Tian, Yue; Bu, Ding Fang; Tang, Chao Shu; DU, Jun Bao

2007-08-18

261

An Investigation of the Potential for a Computer-based Tutorial Program Covering the Cardiovascular System to Replace Traditional Lectures.  

ERIC Educational Resources Information Center

Presents the results of a comparative study to evaluate the effectiveness of two interactive computer-based learning (CBL) programs, covering the cardiovascular system, as an alternative to lectures for first year undergraduate students at a United Kingdom University. Discusses results in relation to the design of evaluative studies and the future…

Dewhurst, D. G.; Williams, A. D.

1998-01-01

262

[Evaluation of compensatory possibilities of the cardiovascular system in patients before reconstructive operations on the aorta and major arteries].  

PubMed

To determine functional reserves of cardiovascular system, two procedures were comparatively studied in evaluation of central hemodynamics: tetrapolar chest rheography under isovolemic loading and rheopolyglucin test. Close correlation registered in results of the tests allowed the authors to employ subsequently the isovolemic test alone. The patients with circulatory subcompensation and decompensation received 7-14-day preoperative cardiostimulation. PMID:1875654

Strelets, B M; Protsenko, N V; Pozin, A A; Petin, G I

1991-02-01

263

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.

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

264

A system-level investigation into the mechanisms of Chinese Traditional Medicine: Compound Danshen Formula for cardiovascular disease treatment.  

PubMed

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

265

Role of sympathoadrenomedullary system in cardiovascular response to stress in rats.  

PubMed

Sympathetic nerve and/or adrenal medulla contributions to stress-induced cardiovascular responses were investigated by factoring out their influence using adrenal demedullation (DMED) and/or chemical sympathectomy with guanethidine (GUAN). Rats divided into 4 groups [sham-operated/saline (SHAM/SAL), SHAM/GUAN, DMED/SAL and DMED/GUAN] were injected i.p. over 4 weeks with either saline or GUAN (25 mg/kg/day). At the end of this treatment period, blood pressure (BP) and heart rate (HR) were monitored via carotid catheter prior to and during restraint in conscious rats. Treatments did not alter basal BP or HR when compared to controls. Restraint increased HR (delta 72 bpm) and systolic, diastolic and mean BP (delta approximately 20 mm Hg) in control animals. Restraint-induced HR change was significantly greater in DMED/SAL animals (delta 88 bpm), but less in SHAM/GUAN animals (delta 40 bpm) than in controls. DMED/GUAN was not different from SHAM/GUAN alone in altering HR response to stress, supporting the greater influence of sympathetic nerves over adrenal medulla in controlling HR. Chronic GUAN abolished normal pressor responses to restraint stress. DMED increased diastolic blood pressure response to stress. However, in DMED/GUAN rats, not only did stress fail to increase blood pressure but rather stress produced hypotension (delta - 34 mm Hg MAP), demonstrating the role of adrenal medulla in maintaining BP during stress. Differential effects of the various treatments on diastolic and systolic pressure suggest that the treatments had effects on peripheral vasculature. These results demonstrate that sympathetic nerves and adrenal medulla have important influences on cardiovascular function during stress and that in the absence of either, the other system may partially compensate.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2625505

Barron, B A; Van Loon, G R

1989-11-01

266

Systemic inflammation: a key factor in the pathogenesis of cardiovascular complications in obstructive sleep apnoea syndrome?  

Microsoft Academic Search

Obstructive sleep apnoea syndrome (OSAS) is a highly prevalent disease and is recognised as a major public health burden. Large-scale epidemiological studies have demonstrated an independent relationship between OSAS and various cardiovascular disorders. The pathogenesis of cardiovascular complications in OSAS is not completely understood but a multifactorial aetiology is likely. Inflammatory processes have emerged as critical in the pathogenesis of

S Ryan; C T Taylor; W T McNicholas

2009-01-01

267

Introduction: Cardiovascular physics  

Microsoft Academic Search

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,

Niels Wessel; Jürgen Kurths; William Ditto; Robert Bauernschmitt

2007-01-01

268

Thromboembolic and cardiovascular risk in rheumatoid arthritis: role of the haemostatic system.  

PubMed

Circumstantial evidence suggests that the innate immune system and coagulation system share a common evolutionary origin, which explains the extensive crosstalk between inflammatory cytokines and coagulation factors, with many components being important for both systems. This crosstalk has been extensively studied in sepsis, an acute state of high-grade inflammation. However, rheumatoid arthritis (RA) as well as many other autoimmune diseases can also be considered as a prothrombotic state. More and more studies show that autoimmune diseases, including RA, are a risk factor for cardiovascular disease, and also for venous thromboembolic events, such as pulmonary embolism and deep vein thrombosis. Inflammation and its effect on the haemostatic system is probably the link between these diseases. This viewpoint gives an update of the current literature on thromboembolic risk in RA, but also documents important knowledge gaps. This viewpoint will therefore help to focus on further research topics to improve diagnostic and therapeutic options which may relieve both the proinflammatory and the prothrombotic burden of autoimmune diseases. PMID:24431395

van den Oever, I A M; Sattar, N; Nurmohamed, M T

2014-06-01

269

Salud para su Corazón: a community-based Latino cardiovascular disease prevention and outreach model.  

PubMed

Cardiovascular disease (CVD) is the leading cause of death for Latinos living in the United States. This population is generally unaware of important lifestyle or behavioral changes that can prevent CVD. The National Heart, Lung, and Blood Institute (NHLBI) designed and implemented Salud para su Corazón (Health for Your Heart), a culturally appropriate, community-based, theory-driven intervention model. NHLBI's goals were: (1) to design an intervention model appropriate to Latino populations; (2) to pilot test the model in a specific community with the objectives of increasing awareness about heart disease, raising knowledge about CVD prevention, and promoting heart-healthy lifestyles; and (3) to disseminate the model and the materials developed to other communities with similar needs. An agency-community partnership, under the leadership of the Community Alliance for Heart Health, guided all stages of the community intervention project. The multimedia bilingual community intervention included television telenovela format public service announcements (PSAs), radio programs, brochures, recipe booklets, charlas, a promotores training manual, and motivational videos. An evaluation survey assessed the impact of the intervention. A pre-post intervention survey was conducted with more than 300 participants, and results showed that the respondents were substantially more aware of risk factors for CVD, and had greatly increased their knowledge of ways to prevent heart disease. Dissemination efforts have resulted in numerous requests by health organizations, universities, and health maintenance organizations (HMOs) for educational materials and communication strategies produced by Salud para su Corazón. In addition, Univision, the largest Spanish-language broadcast television network, is airing the initiative's PSAs. Also, training seminars for promotores are being conducted in different regions of the United States, and several locations are planning to replicate this study. PMID:10555925

Alcalay, R; Alvarado, M; Balcazar, H; Newman, E; Huerta, E

1999-10-01

270

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 ...

271

Erythropoietin Promotes Deleterious Cardiovascular Effects and Mortality Risk in a Rat Model of Chronic Sports Doping  

Microsoft Academic Search

Athletes who abuse recombinant human erythropoietin (rhEPO) consider only the benefit to performance and usually ignore the\\u000a potential short and long-term liabilities. Elevated haematocrit and dehydratation associated with intense exercise may reveal\\u000a undetected cardiovascular risk, but the mechanisms underlying it remain to be fully explained. This study aimed to evaluate\\u000a the cardiovascular effects of rhEPO in rats under chronic aerobic

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

2009-01-01

272

Cardiovascular and organ responses and adaptation responses to hypogravity in an experimental animal model.  

NASA Astrophysics Data System (ADS)

The head-down suspension (i.e antiorthostatic hypokinesia) rat is used to simulate weightlessness. However, little is known about cardiovascular and organ adaptation responses which, over a long time, can become pathologically significant. The purpose of this study was therefore to evaluate regional changes in the hematology parameters, Endotheline-1 (ET-1) concentration and urinary excretion of N-acetyl-?-D-glucosaminidase (EC 3.2.1.30) (NAG) in an experimental antiorthostatic rat model. The data indicate significant variations in the plasma ET-1 level in time, in the superior and inferior cava vessel blood of animals maintained for 10 days in hypogravity with respect to controls. These changes do not seem to be due to hemoconcentration. The increase in urinary NAG was observed during the first 24h of experiment, indicating renal stress, probably due to adverse blood flow variations within the organ. We conclude that the plasma ET-1 level changes could be responsible, overall for the blood flow variations in the kidney and renal stress could be the consequence of extended antiorthostatic hypokinesia. The ET-1 behaviour and urinary NAG excretion in rats exposed to antiorthostatic hypokjnetic hydynamia offer possibilities for understanding if these changes might be reversible or when they become pathological. This could give some relevant information about the effects of prolonged hypogravity during the space voyage.

Biondi, R.; Capodicasa, E.; Tassi, C.; Mezzasomal, L.; Benedetti, C.; Valiani, M.; Marconi, P.; Rossi, R.

1995-10-01

273

Image-based computational fluid dynamics in blood vessel models: toward developing a prognostic tool to assess cardiovascular function changes in prolonged space flights  

NASA Astrophysics Data System (ADS)

One of NASA"s objectives is to be able to perform a complete pre-flight evaluation of possible cardiovascular changes in astronauts scheduled for prolonged space missions. Blood flow is an important component of cardiovascular function. Lately, attention has focused on using computational fluid dynamics (CFD) to analyze flow with realistic vessel geometries. MRI can provide detailed geometrical information and is the only clinical technique to measure all three spatial velocity components. The objective of this study was to investigate the reliability of MRI-based model reconstruction for CFD simulations. An aortic arch model and a carotid bifurcation model were scanned in a 1.5T MRI scanner. Axial MRI acquisitions provided images for geometry reconstruction using different resolution settings. The vessel walls were identified and the geometry was reconstructed using existing software. The geometry was then imported into a commercial CFD package for meshing and numerical solution. MRI velocity acquisitions provided true inlet boundary conditions for steady flow, as well as three-directional velocity data at several locations. In addition, an idealized version of each geometry was created from the model drawings. 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 mean differences <10%. CFD results from different MRI resolution settings did not show significant differences (<5%). This study showed quantitatively that reliable CFD simulations can be performed in models reconstructed from MRI acquisitions and gives evidence that a future, subject-specific, computational evaluation of the cardiovascular system is possible.

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

2005-04-01

274

Construction of a three-dimensional model of cardiovascular disease and deployment of a new method of fostering patient adherence to instruction  

PubMed Central

Background For the patient-oriented medical services, it is important to assist the patient in understanding the management of cardiovascular diseases. The strategy of medication instruction is particularly important to enhance medication adherence. Objective and methods The original model was newly constructed and covers multiple factors, including those related to renin–angiotensin, metabolism of glucose and lipids, blood coagulation, and the organic basis of the disease. The four factors of cardiovascular diseases and their relationship with the disease state are expressed in the form of a tetrahedral model. Results and discussion This disease model illustrates in points, lines, surfaces, and spaces that the factors combine with each other and result in a pathological condition, as determined by the degree of involvement of each factor in a discontinuous manner. The model helps cardiovascular patients to understand visually that there is more than one pathological condition. Our model allowed patients to quickly comprehend the complex pharmacotherapy of cardiovascular diseases by presenting the information in the form of a three-dimensional structure. Lifestyle-related diseases, including cardiovascular diseases, involve complicated factors and require careful pharmacotherapy which is tailored to individual patient needs. In this regard, the development of instructional tools is particularly effective. Conclusion The three-dimensional model shows optimum treatment by correctly considering both the quantity and quality of the four pathological factors associated with cardiovascular diseases. Appropriate patient compliance instruction based on life guidance is thought to be essential in the treatment of cardiovascular diseases.

Nakano, Masuyo; Shirotake, Shoichi

2013-01-01

275

The Effect of Tobacco Control Measures during a Period of Rising Cardiovascular Disease Risk in India: A Mathematical Model of Myocardial Infarction and Stroke  

PubMed Central

Background We simulated tobacco control and pharmacological strategies for preventing cardiovascular deaths in India, the country that is expected to experience more cardiovascular deaths than any other over the next decade. Methods and Findings A microsimulation model was developed to quantify the differential effects of various tobacco control measures and pharmacological therapies on myocardial infarction and stroke deaths stratified by age, gender, and urban/rural status for 2013 to 2022. The model incorporated population-representative data from India on multiple risk factors that affect myocardial infarction and stroke mortality, including hypertension, hyperlipidemia, diabetes, coronary heart disease, and cerebrovascular disease. We also included data from India on cigarette smoking, bidi smoking, chewing tobacco, and secondhand smoke. According to the model's results, smoke-free legislation and tobacco taxation would likely be the most effective strategy among a menu of tobacco control strategies (including, as well, brief cessation advice by health care providers, mass media campaigns, and an advertising ban) for reducing myocardial infarction and stroke deaths over the next decade, while cessation advice would be expected to be the least effective strategy at the population level. In combination, these tobacco control interventions could avert 25% of myocardial infarctions and strokes (95% CI: 17%–34%) if the effects of the interventions are additive. These effects are substantially larger than would be achieved through aspirin, antihypertensive, and statin therapy under most scenarios, because of limited treatment access and adherence; nevertheless, the impacts of tobacco control policies and pharmacological interventions appear to be markedly synergistic, averting up to one-third of deaths from myocardial infarction and stroke among 20- to 79-y-olds over the next 10 y. Pharmacological therapies could also be considerably more potent with further health system improvements. Conclusions Smoke-free laws and substantially increased tobacco taxation appear to be markedly potent population measures to avert future cardiovascular deaths in India. Despite the rise in co-morbid cardiovascular disease risk factors like hyperlipidemia and hypertension in low- and middle-income countries, tobacco control is likely to remain a highly effective strategy to reduce cardiovascular deaths. Please see later in the article for the Editors' Summary

Basu, Sanjay; Glantz, Stanton; Bitton, Asaf; Millett, Christopher

2013-01-01

276

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

277

Cardiovascular Disease, Single Nucleotide Polymorphisms; and the Renin Angiotensin System: Is There a MicroRNA Connection?  

PubMed Central

Essential hypertension is a complex disorder, caused by the interplay between many genetic variants, gene-gene interactions, and environmental factors. Given that the renin-angiotensin system (RAS) plays an important role in blood pressure (BP) control, cardiovascular regulation, and cardiovascular remodeling, special attention has been devoted to the investigation of single-nucleotide polymorphisms (SNP) harbored in RAS genes that may be associated with hypertension and cardiovascular disease. MicroRNAs (miRNAs) are a family of small, ?21-nucleotide long, and nonprotein-coding RNAs that recognize target mRNAs through partial complementary elements in the 3?-untranslated region (3?-UTR) of mRNAs and inhibit gene expression by targeting mRNAs for translational repression or destabilization. Since miRNA SNPs (miRSNPs) can create, destroy, or modify miRNA binding sites, this review focuses on the hypothesis that transcribed target SNPs harbored in RAS mRNAs, that alter miRNA gene regulation and consequently protein expression, may contribute to cardiovascular disease susceptibility.

Elton, Terry S.; Sansom, Sarah E.; Martin, Mickey M.

2010-01-01

278

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

279

Bionic cardiology: exploration into a wealth of controllable body parts in the cardiovascular system.  

PubMed

Bionic cardiology is the medical science of exploring electronic control of the body, usually via the neural system. Mimicking or modifying biological regulation is a strategy used to combat diseases. Control of ventricular rate during atrial fibrillation by selective vagal stimulation, suppression of ischemia-related ventricular fibrillation by vagal stimulation, and reproduction of neurally commanded heart rate are some examples of bionic treatment for arrhythmia. Implantable radio-frequency-coupled on-demand carotid sinus stimulators succeeded in interrupting or preventing anginal attacks but were replaced later by coronary revascularization. Similar but fixed-intensity carotid sinus stimulators were used for hypertension but were also replaced by drugs. Recently, however, a self-powered implantable device has been reappraised for the treatment of drug-resistant hypertension. Closed-loop spinal cord stimulation has successfully treated severe orthostatic hypotension in a limited number of patients. Vagal nerve stimulation is effective in treating heart failure in animals, and a small-size clinical trial has just started. Simultaneous corrections of multiple hemodynamic abnormalities in an acute decompensated state are accomplished simply by quantifying fundamental cardiovascular parameters and controlling these parameters. Bionic cardiology will continue to promote the development of more sophisticated device-based therapies for otherwise untreatable diseases and will inspire more intricate applications in the twenty-first century. PMID:22275044

Sugimachi, Masaru; Sunagawa, Kenji

2009-01-01

280

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

281

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.

2013-01-01

282

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

283

Modeling of dynamic cardiovascular responses during G-transition-induced orthostatic stress in pitch and roll rotations  

Microsoft Academic Search

Dynamic and fuzzy models for a typical subject's cardiovascular response to the orthostatic stress have been developed based on experimental data. In our original study (Cheung et al., 1999), arterial blood pressure (BP) time-series data were obtained using a man-rated tilt table that applies gigahertz-acceleration transitions from +0.861 Gz [head-up (HU)] to -0.707 G [head-down (HD)] and back to +0.861

William W. Melek; Ziren Lu; Alex Kapps; Bob Cheung

2002-01-01

284

Estrogen modifies stress response of catecholamine biosynthetic enzyme genes and cardiovascular system in ovariectomized female rats.  

PubMed

Estrogen is likely involved in the gender specific differences in coping with stress. Activation of catecholamine (CA) biosynthetic enzyme gene expression in central and peripheral CA systems plays a key role in response to stress and in regulation of the cardiovascular system. Here we examined whether estradiol can modulate response of hypothalamic-pituitary-adrenal axis (HPA), gene expression of enzymes related to CA biosynthesis in several noradrenergic locations, tetrahydrobiopterin (BH4) concentration and blood pressure (BP) in response to immobilization stress (IMO) of ovariectomized female rats. Rats were injected with 25 mug/kg estradiol benzoate (EB) or sesame oil once daily for 16 days and subsequently exposed to two hours of IMO. The IMO triggered elevation in plasma ACTH was lessened in EB-pretreated animals. However, estradiol did not alter the IMO-elicited rise of tyrosine hydroxylase mRNA levels in adrenal medulla (AM) and in the nucleus of solitary track (NTS) compared with controls. The response of GTP cyclohydrolase I (GTPCH) mRNA in AM to IMO was also similar in both groups. Several responses to IMO in EB-treated rats were reversed. Instead of IMO-elicited elevation in dopamine beta-hydroxylase mRNA levels in the locus coeruleus, GTPCH mRNA and BH4 levels in the NTS, they were reduced by IMO. In a parallel experiment, BP was monitored during restraint stress. The elevation of BP in response to single or repeated restraint stress was sustained during 2 h in controls and reduced after 70 min stress in EB treated rats. One month after withdrawal of EB treatment, the BP response to restraint was similar to that of rats which never received EB. The results demonstrate that estrogen can modulate responses to stress affecting HPA axis, CA biosynthesis, in central and peripheral noradrenergic systems, and BP. PMID:15802180

Serova, L I; Maharjan, S; Sabban, E L

2005-01-01

285

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

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

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

288

Asymmetric Dimethylarginine as a Surrogate Marker of Endothelial Dysfunction and Cardiovascular Risk in Patients with Systemic Rheumatic Diseases  

PubMed Central

The last few decades have witnessed an increased life expectancy of patients suffering with systemic rheumatic diseases, mainly due to improved management, advanced therapies and preventative measures. However, autoimmune disorders are associated with significantly enhanced cardiovascular morbidity and mortality not fully explained by traditional cardiovascular disease (CVD) risk factors. It has been suggested that interactions between high-grade systemic inflammation and the vasculature lead to endothelial dysfunction and atherosclerosis, which may account for the excess risk for CVD events in this population. Diminished nitric oxide synthesis—due to down regulation of endothelial nitric oxide synthase—appears to play a prominent role in the imbalance between vasoactive factors, the consequent impairment of the endothelial hemostasis and the early development of atherosclerosis. Asymmetric dimethylarginine (ADMA) is one of the most potent endogenous inhibitors of the three isoforms of nitric oxide synthase and it is a newly discovered risk factor in the setting of diseases associated with endothelial dysfunction and adverse cardiovascular events. In the context of systemic inflammatory disorders there is increasing evidence that ADMA contributes to the vascular changes and to endothelial cell abnormalities, as several studies have revealed derangement of nitric oxide/ADMA pathway in different disease subsets. In this article we discuss the role of endothelial dysfunction in patients with rheumatic diseases, with a specific focus on the nitric oxide/ADMA system and we provide an overview on the literature pertaining to ADMA as a surrogate marker of subclinical vascular disease.

Dimitroulas, Theodoros; Sandoo, Aamer; Kitas, George D.

2012-01-01

289

Share and enjoy: anatomical models database--generating and sharing cardiovascular model data using web services.  

PubMed

Sharing data between scientists and with clinicians in cardiac research has been facilitated significantly by the use of web technologies. The potential of this technology has meant that information sharing has been routinely promoted through databases that have encouraged stakeholder participation in communities around these services. In this paper we discuss the Anatomical Model Database (AMDB) (Gianni et al. Functional imaging and modeling of the heart. Springer, Heidelberg, 2009; Gianni et al. Phil Trans Ser A Math Phys Eng Sci 368:3039-3056, 2010) which both facilitate a database-centric approach to collaboration, and also extends this framework with new capabilities for creating new mesh data. AMDB currently stores cardiac geometric models described in Gianni et al. (Functional imaging and modelling of the heart. Springer, Heidelberg, 2009), a number of additional cardiac models describing geometry and functional properties, and most recently models generated using a web service. The functional models represent data from simulations in geometric form, such as electrophysiology or mechanics, many of which are present in AMDB as part of a benchmark study. Finally, the heartgen service has been added for producing left or bi-ventricle models derived from binary image data using the methods described in Lamata et al. (Med Image Anal 15:801-813, 2011). The results can optionally be hosted on AMDB alongside other community-provided anatomical models. AMDB is, therefore, a unique database storing geometric data (rather than abstract models or image data) combined with a powerful web service for generating new geometric models. PMID:23436208

Kerfoot, Eric; Lamata, Pablo; Niederer, Steve; Hose, Rod; Spaan, Jos; Smith, Nic

2013-11-01

290

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

291

Characteristics and popular topics of latest researches into the effects of air particulate matter on cardiovascular system by bibliometric analysis.  

PubMed

In recent years, many epidemiological and toxicological studies have investigated the adverse effects of air particulate matter (PM) on the cardiovascular system. However, it is difficult for the researchers to have a timely and effective overall command of the latest characteristics and popular topics in such a wide field. Different from the previous reviews, in which the research characteristics and trends are empirically concluded by experts, we try to have a comprehensive evaluation of the above topics for the first time by bibliometric analysis, a quantitative tool in information exploration. This study aims to introduce the bibliometric method into the field of PM and cardiovascular system. The articles were selected by searching PubMed/MEDLINE (from 2007 to 2012) using Medical Subject Headings (MeSH) terms "particulate matter" and "cardiovascular system". A total of 935 eligible articles and 1895 MeSH terms were retrieved and processed by the software Thomson Data Analyzer (TDA). The bibliographic information and the MeSH terms of these articles were classified and analyzed to summarize the research characteristics. The top 200 high-frequency MeSH terms (the cumulative frequency percentage was 74.2%) were clustered for popular-topic conclusion. We summarized the characteristics of published articles, of researcher collaborations and of the contents. Ten clusters of MeSH terms are presented. Six popular topics are concluded and elaborated for reference. Our study presents an overview of the characteristics and popular topics in the field of PM and cardiovascular system in the past five years by bibliometric tools, which may provide a new perspective for future researchers. PMID:23480197

Jia, Xiaofeng; Guo, Xinbiao; Li, Haicun; An, Xinying; Zhao, Yingguang

2013-03-01

292

A farnesyltransferase inhibitor prevents both the onset and late progression of cardiovascular disease in a progeria mouse model  

PubMed Central

Hutchinson-Gilford progeria syndrome (HGPS) is the most dramatic form of human premature aging. Death occurs at a mean age of 13 years, usually from heart attack or stroke. Almost all cases of HGPS are caused by a de novo point mutation in the lamin A (LMNA) gene that results in production of a mutant lamin A protein termed progerin. This protein is permanently modified by a lipid farnesyl group, and acts as a dominant negative, disrupting nuclear structure. Treatment with farnesyltransferase inhibitors (FTIs) has been shown to prevent and even reverse this nuclear abnormality in cultured HGPS fibroblasts. We have previously created a mouse model of HGPS that shows progressive loss of vascular smooth muscle cells in the media of the large arteries, in a pattern that is strikingly similar to the cardiovascular disease seen in patients with HGPS. Here we show that the dose-dependent administration of the FTI tipifarnib (R115777, Zarnestra) to this HGPS mouse model can significantly prevent both the onset of the cardiovascular phenotype as well as the late progression of existing cardiovascular disease. These observations provide encouraging evidence for the current clinical trial of FTIs for this rare and devastating disease.

Capell, Brian C.; Olive, Michelle; Erdos, Michael R.; Cao, Kan; Faddah, Dina A.; Tavarez, Urraca L.; Conneely, Karen N.; Qu, Xuan; San, Hong; Ganesh, Santhi K.; Chen, Xiaoyan; Avallone, Hedwig; Kolodgie, Frank D.; Virmani, Renu; Nabel, Elizabeth G.; Collins, Francis S.

2008-01-01

293

Cardiovascular reactivity after blockade of angiotensin AT1 receptors in the experimental model of tilting test in conscious rats  

PubMed Central

Background and purpose: Studies have shown that the angiotensin II AT1 receptor antagonist, losartan, accentuates the hypotensive response in the orthostatic stress test (tilt) performed in anaesthetized rats. The same effect was not reported with other AT1 antagonists. The aim of this study was to re-evaluate the effects of AT1 receptor blockade on the cardiovascular response to tilt in a model developed for conscious rats. Experimental approach: Rats (n=5–7 per group) were instrumented for infusion of drugs and recording of cardiovascular parameters and, after recovery, placed in a plastic tube positioned over the tilt board. The tilt test was conducted by raising the head side of the tilt board from horizontal position to 75° head up position for 15?min. Key results: Compared with control group (NaCl 0.9%, 1?ml?kg?1), oral treatment with 1?mg?kg?1 per day of losartan or telmisartan did not alter the blood pressure response during tilt. With the 10?mg?kg?1 dose, both antagonists altered the blood pressure response during tilt (mean maximum changes ?11±3?mm?Hg; P<0.01). A post-tilt hypotension was observed with both doses in losartan and telmisartan groups (?13±1 and ?9±2?mm?Hg, respectively; P<0.01). Conclusions and implications: The present results indicate that the effect of losartan on the cardiovascular reactivity to tilt shares a similar profile to that of other AT1 antagonists. Evidence discussed addresses the importance of using a conscious model for testing the influence of antihypertensive drugs on the cardiovascular reactivity to orthostatic challenges.

Bedette, D; Santos, R A S; Fontes, M A P

2008-01-01

294

The insulin-like growth factor system, metabolic syndrome, and cardiovascular disease risk.  

PubMed

The metabolic syndrome is a combination of metabolic and clinical features that aggregate in individuals and increase cardiovascular disease (CVD) risk considerably. It is believed, although sometimes controversially, that the underlying basis for this syndrome is insulin resistance (IR) and accompanying compensatory hyperinsulinemia. Insulin and insulin-like growth factors (IGFs) have significant homology and interact with differing affinity with the same receptors. Therefore, their actions can be complementary, and this becomes particularly significant clinico-pathologically when their circulating levels are altered. This review of currently available information attempts to answer the following questions: (1) Is there any evidence for changes in the components of the IGF system in individuals with established CVD or with increased CVD risk as with the metabolic syndrome? (2) What are the underlying mechanisms for interactions, if any, between insulin and the IGF system, in the genesis of CVD? (3) Can knowledge of the pathophysiological changes in the IGF system observed in macrosomic newborn infants and growth hormone (GH)-treated children and adults explain some of the observations in relation to the IGF system and the metabolic syndrome? (4) Can the experimental and clinical evidence adduced from the foregoing be useful in designing novel therapies for the prevention, treatment, and assignment of prognosis in metabolic syndrome-associated disease, particularly ischemic heart disease? To answer these questions, we have performed a literature review using bibliographies from PubMed, Medline, and Google Scholar published within the last 10 years. We suggest that IGF-1 levels are reduced consistently in individuals with the metabolic syndrome and its components and in those with ischemic CVD. Such changes are also seen with GH deficiency in which these changes are partially reversible with GH treatment. Furthermore, changes are seen in levels and interactions of IGF-binding proteins in these disorders, and some of these changes appear to be independent of IGF-binding capability and could potentially impact on risk for the metabolic syndrome and CVD. The promising therapeutic implications of these observations are also discussed. PMID:22103319

Akanji, Abayomi O; Smith, Robert J

2012-02-01

295

The Development of a Model for Adult Education in Nutrition and Cardiovascular Disease.  

ERIC Educational Resources Information Center

Two nutrition education modules were developed on cardiovascular disease and fat-controlled diet consisting of a self-instruction leader's guide and teaching package to conduct learning sessions for the participants. The sessions consisted of an audio-visual presentation, situations related to the module topic, group discussion, role-playing,…

Walker, Susan K.; Villano, Maurice W.

296

Evaluating the evidence for models of life course socioeconomic factors and cardiovascular outcomes: a systematic review  

Microsoft Academic Search

BACKGROUND: A relatively consistent body of research supports an inverse graded relationship between socioeconomic status (SES) and cardiovascular disease (CVD). More recently, researchers have proposed various life course SES hypotheses, which posit that the combination, accumulation, and\\/or interactions of different environments and experiences throughout life can affect adult risk of CVD. Different life course designs have been utilized to examine

Ricardo A Pollitt; Kathryn M Rose; Jay S Kaufman

2005-01-01

297

The effectiveness and cost effectiveness of dark chocolate consumption as prevention therapy in people at high risk of cardiovascular disease: best case scenario analysis using a Markov model  

PubMed Central

Objective To model the long term effectiveness and cost effectiveness of daily dark chocolate consumption in a population with metabolic syndrome at high risk of cardiovascular disease. Design Best case scenario analysis using a Markov model. Setting Australian Diabetes, Obesity and Lifestyle study. Participants 2013 people with hypertension who met the criteria for metabolic syndrome, with no history of cardiovascular disease and not receiving antihypertensive therapy. Main outcome measures Treatment effects associated with dark chocolate consumption derived from published meta-analyses were used to determine the absolute number of cardiovascular events with and without treatment. Costs associated with cardiovascular events and treatments were applied to determine the potential amount of funding required for dark chocolate therapy to be considered cost effective. Results Daily consumption of dark chocolate (polyphenol content equivalent to 100 g of dark chocolate) can reduce cardiovascular events by 85 (95% confidence interval 60 to 105) per 10?000 population treated over 10 years. $A40 (£25; €31; $42) could be cost effectively spent per person per year on prevention strategies using dark chocolate. These results assume 100% compliance and represent a best case scenario. Conclusions The blood pressure and cholesterol lowering effects of dark chocolate consumption are beneficial in the prevention of cardiovascular events in a population with metabolic syndrome. Daily dark chocolate consumption could be an effective cardiovascular preventive strategy in this population.

2012-01-01

298

Investigations of the Cardiovascular and Respiratory Systems on Board the International Space Station: Experiments Puls and Pneumocard  

NASA Astrophysics Data System (ADS)

parameters describing the results of the function of these systems like heart rate, arterial pressure, cardiac output, or breathing frequency, concentration of O2 and CO2 , etc. Missing significant changes of these parameters during weightlessness supports the hypothesis that adaptational and compensatory mechanisms are sufficient and guarantee cardiovascular homeostasis under changing environmental conditions. characteristic changes of the vegetative balance and of the activity of different regulatory elements at the brainstem and subcortical level. This changes guaranteed the adaptation to long term weightlessness. However, it remains unclear to what extent the different levels are involved. Moreover, the criteria describing the efficacy of cardiorespiratory interaction for the different functional states are not defined yet. The investigation of this problems is highly relevant in order to improve the medical control, especially if considering that the disruption of regulatory systems mostly precedes dangerous destruction of homeostasis. cardiovascular and respiratory function on Board the International Space Station (ISS) aiming to obtain new insights into the interaction between different regulatory elements. "Puls" is measures ECG, photoplethysmogram (PPG), and the pneumotachogram (PTG). The ECG is used to measure time series of R-R intervals and to analyse HRV. PPG is used to define the pulse wave velocity, phases of the cardiac cycle, and an estimate of the filling of finger vessels. The variability of these parameters is also calculated and compared to HRV. The analysis of the PTG allows to describe the interaction of the regulatory parameters of the cardiovascular and respiratory systems. Hence, an important feature of the experiment "Puls" is the investigation of regulatory mechanisms rather than of cardiovascular homeostasis. cardiography) and left ventricular contractility (seismocardiography) will be obtained. This expansion is of major importance because, it allows us to get deeper insight into regulatory mechanisms of the cardiorespiratory system and into the state of cardiovascular homeostasis. have the same size (90 x 60 x 20 mm), identical technology, and identical interfaces with the computer. the onboard experiment and to store the obtained data; 2) "Editor": to archive and dearchive the obtained data, to edit them and to insert necessary comments and markers; 3) "Earth": to edit and analyse the data under laboratory conditions.The subprogram "Earth" is an original software package for data analysis, peak detection, calculation of a variety of parameters, time series forming and editing, statistical and spectral time series analysis. Furthermore, a specialized data base is designated for storing of the biosignals, results of analysis, information about the investigated subjects and comments of simple autonomic function tests will allow to assess different elements of the regulatory mechanisms. Special interest will be given to respiratory tests in order to evaluate the interaction between the cardiovascular system and respiration. volunteers and in patients with different cardiovascular diseases. The results were used to establish normal values and criteria for the prognosis of pathologic changes. These materials will be used at valuation the data obtained during researches on ISS. respiratory systems onboard the ISS are the following: 1) definition of the most important parameters, which can be measured simple and reliable during weightlessness; 2) development of miniaturized devices which can be kept on the astronauts body and which could be used in future as an autonomic system of operational medical control; 3) development of original software packages which allow to detect prognostic changes of the regulatory pattern preceding diseases and based on time series analysis of a large number of cardiorespiratory parameters.

Baranov, V. M.; Baevsky, R. M.; Drescher, J.; Tank, J.

299

Adenosine and Adenosine Receptors in the Cardiovascular System: Biochemistry, Physiology, and Pharmacology  

Microsoft Academic Search

Cardiomyocytes and vascular cells readily form, transport, and metabolize the endogenous adenine nucleoside adenosine and act to regulate both interstitial and plasma adenosine concentrations. Cardiovascular cells also have membrane adenosine receptors. Cell and tissue distributions, signal transduction pathways, and pharmacology of each of the four subtypes of adenosine receptors are subjects of intense investigation. The A1-adenosine receptors mediate the negative

1997-01-01

300

Effects of calcium intake on the cardiovascular system in postmenopausal women.  

PubMed

The use of calcium supplements for the prevention of complications of osteoporosis has significantly increased during the last years. The effects of calcium intake in postmenopausal women on cardiovascular parameters such as blood pressure, serum lipids and cardiovascular events are controversial. Even though transient beneficial effects of calcium supplementation have been reported, especially in women with low dietary calcium intake, their long-term outcomes are inconclusive. Only a very few studies investigating serum lipids in postmenopausal women have been described and these showed significant increases in high-density lipoprotein and high-density lipoprotein to low-density lipoprotein ratio. With regards to cardiovascular events in this population group adverse effects have been reported on the rates of myocardial infarction and stroke with increased calcium intake by some authors, however, others described no effects or even beneficial outcomes. We present a review of the current literature which provides a balanced summary of the possible beneficial and adverse effects of calcium intake in postmenopausal women on cardiovascular parameters. Taking into account the modest effect of calcium supplementation in reducing fracture rates, a reassessment of the role, benefits and adverse effects of calcium supplements should be conducted in postmenopausal women. PMID:24125401

Challoumas, D; Cobbold, C; Dimitrakakis, G

2013-11-01

301

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.

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

302

Pathophysiology of isoprostanes in the cardiovascular system: implications of isoprostane-mediated thromboxane A2 receptor activation.  

PubMed

Isoprostanes are free radical-catalysed PG-like products of unsaturated fatty acids, such as arachidonic acid, which are widely recognized as reliable markers of systemic lipid peroxidation and oxidative stress in vivo. Moreover, activation of enzymes, such as COX-2, may contribute to isoprostane formation. Indeed, formation of isoprostanes is considerably increased in various diseases which have been linked to oxidative stress, such as cardiovascular disease (CVD), and may predict the atherosclerotic burden and the risk of cardiovascular complications in the latter patients. In addition, several isoprostanes may directly contribute to the functional consequences of oxidant stress via activation of the TxA2 prostanoid receptor (TP), for example, by affecting endothelial cell function and regeneration, vascular tone, haemostasis and ischaemia/reperfusion injury. In this context, experimental and clinical data suggest that selected isoprostanes may represent important alternative activators of the TP receptor when endogenous TxA2 levels are low, for example, in aspirin-treated individuals with CVD. In this review, we will summarize the current understanding of isoprostane formation, biochemistry and (patho) physiology in the cardiovascular context. PMID:24646155

Bauer, Jochen; Ripperger, Anne; Frantz, Stefan; Ergün, Süleyman; Schwedhelm, Edzard; Benndorf, Ralf A

2014-07-01

303

A mathematical model for dynamics of cardiovascular drug action: Application to intravenous dihydropyridines in healthy volunteers  

Microsoft Academic Search

A physiologically based mathematical model was built to describe the pharmacodynamic effects in response to the administration of intravenous (iv)dihydropyridine drugs in healthy volunteers. This model incorporates a limited number of hemodynamic variables, namely, mean arterial blood pressure (MAP),cardiac output (CO)or heart rate (HR),stroke volume (SV),and total peripheral resistance (TPR),into a closed-loop system supposed to represent essential features of the

Patrice Francheteau; Jean-Louis Steimer; Henri Merdjan; Madeleine Guerret; Claude Dubray

1993-01-01

304

Sympathetic nervous system activity and cardiovascular homeostatis during head-up tilt in patients with spinal cord injuries.  

PubMed

The relationship between sympathetic nervous system activity and cardiovascular responses to head-up tilt in patients with spinal cord injuries and in able-bodied subjects was studied. Twenty-seven adults, nine in each of the three groups (tetraplegia, paraplegia, and able-bodied subjects) were tilted 70 degrees, head up, for 12 minutes after 20 minutes supine rest. Differences between steady-state measurements of mean arterial pressure, stroke volume, and sympathetic nervous system activity were estimated in both positions. Sympathetic nervous system activity was reflected by the low-frequency peak of the blood pressure variability spectrum. From supine rest to head-up tilt, low-frequency power increased in able-bodied subjects (median, 0.42 mm Hg2, p = 0.003), which was different (p = 0.015) from patients with tetraplegia and paraplegia (-0.15 and -0.10 mm Hg2, respectively). Stroke volume and mean arterial pressure decreased in patients with tetraplegia (-40% and -9 mm Hg, respectively; p = 0.008, both variables) more than in able-bodied subjects (-33%, 11 mm Hg, respectively) or patients with paraplegia (-24%, 8 mm Hg, respectively). Results indicated increased sympathetic nervous system activity during head-up tilt in able-bodied subjects, but not in patients with paraplegia or tetraplegia, whereas patients with tetraplegia, but not paraplegia, showed poorer cardiovascular homeostasis than able-bodied subjects. This suggests that patients with paraplegia maintained cardiovascular homeostasis during head-up tilt without increased sympathetic nervous system activity. PMID:11029019

Houtman, S; Oeseburg, B; Hughson, R L; Hopman, M T

2000-08-01

305

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

306

Controversies in Cardiovascular Research: Induced pluripotent stem cell-derived cardiomyocytes - boutique science or valuable arrhythmia model?  

PubMed Central

As part of the series on Controversies in Cardiovascular Research, the article reviews the strengths and limitations of induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM) as models of cardiac arrhythmias. Specifically, the article attempts to answer the following questions: Which clinical arrhythmias can be modeled by iPSC-CM? How well can iPSC-CM model adult ventricular myocytes? What are the strengths and limitations of published iPSC-CM arrhythmia models? What new mechanistic insight has been gained? What is the evidence that would support using iPSC-CM to personalize anti-arrhythmic drug therapy? The review also discusses the pros and cons of using the iPSC-CM technology for modeling specific genetic arrhythmia disorders such as long QT syndrome, Brugada Syndrome or Catecholaminergic Polymorphic Ventricular Tachycardia.

Knollmann, Bjorn C

2013-01-01

307

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

308

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.

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

309

Sheep, pig, and human platelet-material interactions with model cardiovascular biomaterials.  

PubMed

The relationship between cardiovascular device performance in animals and humans is not straightforward. As the principal formed element in a thrombus, platelets play a major role in determining the hemocompatibility of mechanical heart valves and other high-shear-rate cardiovascular devices. Since larger animals are required to test many such devices, sheep and porcine platelet responses were compared to humans. Adhesion, spreading, and the formation of thrombilike structures were examined in vitro on pyrolytic carbon mechanical heart valve leaflets, National Institutes of Health-reference polyethylene and silicone rubber, and Formvar. Principal findings were that platelet responses are strongly dependent upon the biomaterial and the species: Porcine and human platelets spread extensively on pyrolytic carbon, formed thrombuslike structures on Formvar, and were least active on silicone rubber. Human and porcine platelets responded differently to polyethylene: Human platelets spread extensively, while porcine platelets remained pseudopodial. In contrast, sheep platelets attached much less, never reached fully spread shapes, and were far less active overall. Since porcine responses were generally similar to humans, pigs may be a useful predictor of in vivo platelet-biomaterial interaction in humans. Conversely, as ovine platelets were much less active, this must be accounted for in the evaluation of cardiovascular devices tested in sheep. PMID:10397982

Goodman, S L

1999-06-01

310

Introducing a model of cardiovascular prevention in Nairobi's slums by integrating a public health and private-sector approach: the SCALE-UP study  

PubMed Central

Introduction Cardiovascular disease (CVD) is a leading cause of death in sub-Saharan Africa (SSA), with annual deaths expected to increase to 2 million by 2030. Currently, most national health systems in SSA are not adequately prepared for this epidemic. This is especially so in slum settlements where access to formal healthcare and resources is limited. Objective To develop and introduce a model of cardiovascular prevention in the slums of Nairobi by integrating public health and private sector approaches. Study design Two non-profit organizations that conduct public health research, Amsterdam Institute for Global Health and Development (AIGHD) and African Population and Health Research Center (APHRC), collaborated with private-sector Boston Consulting Group (BCG) to develop a service delivery package for CVD prevention in slum settings. A theoretic model was designed based on the integration of public and private sector approaches with the focus on costs and feasibility. Results The final model includes components that aim to improve community awareness, a home-based screening service, patient and provider incentives to seek and deliver treatment specifically for hypertension, and adherence support. The expected outcomes projected by this model could prove potentially cost effective and affordable (1 USD/person/year). The model is currently being implemented in a Nairobi slum and is closely followed by key stakeholders in Kenya including the Ministry of Health, the World Health Organization (WHO), and leading non-governmental organizations (NGOs). Conclusion Through the collaboration of public health and private sectors, a theoretically cost-effective model was developed for the prevention of CVD and is currently being implemented in the slums of Nairobi. If results are in line with the theoretical projections and first impressions on the ground, scale-up of the service delivery package could be planned in other poor urban areas in Kenya by relevant policymakers and NGOs.

van de Vijver, Steven; Oti, Samuel; Tervaert, Thijs Cohen; Hankins, Catherine; Kyobutungi, Catherine; Gomez, Gabriela B.; Brewster, Lizzy; Agyemang, Charles; Lange, Joep

2013-01-01

311

Emerging anti-cancer therapeutic targets and the cardiovascular system: Is there cause for concern?  

PubMed Central

The race for a cure to cancer continues, fueled by unprecedented discoveries of fundamental biology underlying carcinogenesis and tumorogenesis. The expansion of the target list and tools to approach them is moving the oncology community extraordinarily rapidly to clinical trials, bringing new hope for cancer victims. This effort is also propelling biological discoveries in cardiovascular research as many of the targets being explored in cancer play fundamental roles in the heart and vasculature. The combined efforts of cardiovascular and cancer biologists, along with clinical investigators in these fields, will be needed to understand how to safely exploit these efforts. Here we discuss a few of the many research foci in oncology where we believe such collaboration will be particularly important.

Peng, Xuyang; Pentassuglia, Laura; Sawyer, Douglas B.

2010-01-01

312

Studies on the GABAergic system in cardiovascular control in normotensive and in sinoaortic denervated rats.  

PubMed

The cardiovascular effects of i.v. gamma-amino-beta-hydroxybutyric acid (GABOB) were investigated in rats anaesthetized with urethane. GABOB produced a dose-dependent hypotensive response. Treatment with GABA-A receptor antagonists prevented the GABOB response while the GABA stimulation by diazepam enhanced this response. The beta 1-adrenoceptor antagonist reduced the GABOB-induced hypotension but beta 2-adrenoceptor antagonists did not affect it. Picrotoxin, bicuculline or diazepam produced an increase in basal blood pressure. Fifteen days after sinoaortic denervation in rats the glutamic acid decarboxylase and the aminobutyric acid transaminase (GABA-T) activities were significantly reduced in dorsal pons and in anterior hypothalamus whereas GABA-T activity was increased in ventral medulla oblongata. Our results demonstrate that GABOB stimulates GABA-A receptors in anaesthetized rats and thus exerts a neuromodulatory effect on cardiovascular function. GABAergic neurotransmission participates in the sinoaortic deafferentation in rats. PMID:2854014

Enero, M A; Solignac, D; Apud, J A

1988-01-01

313

Power system load modelling  

Microsoft Academic Search

This paper describes the progress that has been made by the authors in developing a device and a technique for power system load modelling. The applications developed under the FACTS initiative and the system identification technique using the correlation method with pseudo random sequences (PRS) have been adopted for signal injection and load modelling. Simulation studies for load modelling using

Y. Wang; N. C. Pahalawaththa

1998-01-01

314

Cyclic GMP-Dependent Protein Kinases and the Cardiovascular System Insights From Genetically Modified Mice  

Microsoft Academic Search

Signaling cascades initiated by nitric oxide (NO) and natriuretic peptides (NPs) play an important role in the maintenance of cardiovascular homeostasis. It is currently accepted that many effects of these endogenous signaling molecules are mediated via stimulation of guanylyl cyclases and intracellular production of the second messenger cGMP. Indeed, cGMP-elevating drugs like glyceryl trinitrate have been used for more than

Rudi F. Busse; Robert Feil; Suzanne M. Lohmann; Hugo de Jonge; Ulrich Walter; Franz Hofmann

315

Modeling AGV systems  

Microsoft Academic Search

Computer simulation is often used as an analysis tool during the design of Automated Guided Vehicle (AGV) systems. However, because of the complexities inherent in automated material handling systems, general-purpose simulation languages must be used creatively to capture the desired detail in the model. This paper presents some general concepts which can be used to model AGV systems. Also, some

Deborah A. Davis; Calder Sq

1986-01-01

316

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.

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

2012-01-01

317

Resonance Raman spectra of transient species of a respiration enzyme detected with an artificial cardiovascular system and Raman/absorption simultaneous measurement system  

NASA Astrophysics Data System (ADS)

Developments of our techniques for detecting resonance Ranian spectra of reaction intermediates of cytochroxne oxidase are suiainarized. It is demonstrated that combination of a device for Ranian/absorption simultaneous ineasurenient system with an artificial cardiovascular system enabled us to detect the FeO2 and Fe" O stretching vibrations for intermediates and thus to conclude that compounds A and B have the Fe''1-02 and Fe hexnes respectively. 1.

Kitagawa, Teizo; Ogura, Takashi

1991-05-01

318

Design of an ex vivo culture system to investigate the effects of shear stress on cardiovascular tissue.  

PubMed

Mechanical forces are known to affect the biomechanical properties of native and engineered cardiovascular tissue. In particular, shear stress that results from the relative motion of heart valve leaflets with respect to the blood flow is one important component of their mechanical environment in vivo. Although different types of bioreactors have been designed to subject cells to shear stress, devices to expose biological tissue are few. In an effort to address this issue, the aim of this study was to design an ex vivo tissue culture system to characterize the biological response of heart valve leaflets subjected to a well-defined steady or time-varying shear stress environment. The novel apparatus was designed based on a cone-and-plate viscometer. The device characteristics were defined to limit the secondary flow effects inherent to this particular geometry. The determination of the operating conditions producing the desired shear stress profile was streamlined using a computational fluid dynamic (CFD) model validated with laser Doppler velocimetry. The novel ex vivo tissue culture system was validated in terms of its capability to reproduce a desired cone rotation and to maintain sterile conditions. The CFD results demonstrated that a cone angle of 0.5 deg, a cone radius of 40 mm, and a gap of 0.2 mm between the cone apex and the plate could limit radial secondary flow effects. The novel cone-and-plate permits to expose nine tissue specimens to an identical shear stress waveform. The whole setup is capable of accommodating four cone-and-plate systems, thus concomitantly subjecting 36 tissue samples to desired shear stress condition. The innovative design enables the tissue specimens to be flush mounted in the plate in order to limit flow perturbations caused by the tissue thickness. The device is capable of producing shear stress rates of up to 650 dyn cm(-2) s(-1) (i.e., maximum shear stress rate experienced by the ventricular surface of an aortic valve leaflet) and was shown to maintain tissue under sterile conditions for 120 h. The novel ex vivo tissue culture system constitutes a valuable tool toward elucidating heart valve mechanobiology. Ultimately, this knowledge will permit the production of functional tissue engineered heart valves, and a better understanding of heart valve biology and disease progression. PMID:18532871

Sucosky, Philippe; Padala, Muralidhar; Elhammali, Adnan; Balachandran, Kartik; Jo, Hanjoong; Yoganathan, Ajit P

2008-06-01

319

Plasma from systemic lupus patients compromises cholesterol homeostasis: a potential mechanism linking autoimmunity to atherosclerotic cardiovascular disease  

Microsoft Academic Search

Atherosclerotic cardiovascular disease (ASCVD) contributes to morbidity and mortality in systemic lupus erythematosus (SLE).\\u000a Immunologic derangements may disrupt cholesterol balance in vessel wall monocytes\\/macrophages and endothelium. We determined\\u000a whether lupus plasma impacts expression of cholesterol 27-hydroxylase, an anti-atherogenic cholesterol-degrading enzyme that\\u000a promotes cellular cholesterol efflux, in THP-1 human monocytes and primary human aortic endothelial cells (HAEC). THP-1 monocytes\\u000a and HAEC

Allison B. Reiss; Kamran Anwar; Joan T. Merrill; Edwin S. L. Chan; Nahel W. Awadallah; Bruce N. Cronstein; H. Michael Belmont; Elise Belilos; Gary Rosenblum; Kristina Belostocki; Lois Bonetti; Kowser Hasneen; Steven E. Carsons

2010-01-01

320

Hellfire System Model Validation.  

National Technical Information Service (NTIS)

The hybrid simulation facilities, system modeling, and validation process for a U.S. Army missile development program are discussed. Two fundamental problems in missile system design and development require an accurate, valid, proven computer simulation; ...

R. V. Hupp

1988-01-01

321

Cardiovascular Genomics  

PubMed Central

Purpose This article provides an update on cardiovascular genomics using three clinically relevant exemplars, including myocardial infarction (MI) and coronary artery disease (CAD), stroke, and sudden cardiac death (SCD). Organizational Construct Recent advances in cardiovascular genomic research, testing, and clinical implications are presented. Methods Genomic nurse experts reviewed and summarized recent salient literature to provide updates on three selected cardiovascular genomic conditions. Findings Research is ongoing to discover comprehensive genetic markers contributing to many common forms of cardiovascular disease (CVD), including MI and stroke. However, genomic technologies are increasingly being used clinically, particularly in patients with long QT syndrome (LQTS) or hypertrophic cardiomyopathy (HCM) who are at risk for SCD. Conclusions Currently, there are no clinically recommended genetic tests for many common forms of CVD even though direct-to-consumer genetic tests are being marketed to healthcare providers and the general public. On the other hand, genetic testing for patients with certain single gene conditions, including channelopathies (e.g., LQTS) and cardiomyopathies (e.g., HCM), is recommended clinically. Clinical Relevance Nurses play a pivotal role in cardiogenetics and are actively engaged in direct clinical care of patients and families with a wide variety of heritable conditions. It is important for nurses to understand current development of cardiovascular genomics and be prepared to translate the new genomic knowledge into practice.

Wung, Shu-Fen; Hickey, Kathleen T.; Taylor, Jacquelyn Y.; Gallek, Matthew J.

2013-01-01

322

Increased superoxide anion production is associated with early atherosclerosis and cardiovascular dysfunctions in a rabbit model  

Microsoft Academic Search

Objective  Hypercholesterolemia (HC) has been associated with impairment of vascular and myocardial functions. As HC could generate an\\u000a alteration in the oxidative status, we studied the effects of a 1-month cholesterol diet on cardiovascular oxidative stress.\\u000a \\u000a \\u000a \\u000a Methods and Results  New Zealand rabbits received cholesterol (1%) or normal chow for 1 month. At 30 days, superoxide anion levels, assessed by\\u000a ESR spectroscopy, NAD(P)H oxidase (NOX)

Bertrand Collin; David Busseuil; Marianne Zeller; Caroline Perrin; Olivier Barthez; Laurence Duvillard; Catherine Vergely; Marc Bardou; Monique Dumas; Yves Cottin; Luc Rochette

2007-01-01

323

Effect of the novel orally active angiotensin converting enzyme inhibitor alacepril on cardiovascular system in experimental animals.  

PubMed

Effects of 1-[(S)-3-acetylthio-2-methylpropanoyl]-L-prolyl-L-phenylalanine (alacepril, DU-1219) a new orally active angiotensin converting enzyme (ACE) inhibitor, on cardiovascular system in experimental animals were examined. In conscious renal hypertensive dogs, alacepril (3 mg/kg p.o.) caused a marked reduction in systolic and diastolic blood pressure (SBP and DBP) and total peripheral vascular resistance (TPR), but did not change significantly heart rate (HR), cardiac output (CO), stroke volume (SV), cardiac work (CW) and electrocardiogram (ECG). Captopril (3 mg/kg, p.o.) showed similar changes in cardiovascular parameters as alacepril. In anesthetized open-chest normotensive dogs, alacepril (3-100 micrograms/kg/min for 10 min, i.v. infusion) tended to decrease DBP and TPR, but did not change significantly CO, stroke work (SW), left ventricular end diastolic pressure (LVEDP), dp/dt and HR. Captopril also showed similar effects but these changes were greater in extent than those of alacepril. In conscious renal hypertensive rats, alacepril did not affect the regional cerebral blood flow in the frontal cortex and the dorsal hippocampus after single (3 and 10 mg/kg) and successive (3 mg/kg/d for 7 days) oral administration. Captopril (10 mg/kg) significantly decreased blood flow in the frontal cortex after single oral administration. In conscious normotensive dogs, alacepril (3 and 30 mg/kg p.o.) increased renal plasma flow (RPF), urine volume (UV), urinary sodium excretion (UNaV) and urinary Na+/k+ ratio, but did not change glomerular filtration rate (GFR) and urinary potassium excretion (UKV). Captopril (3 and 30 mg/kg p.o.) also showed similar changes as alacepril. These effects of alacepril on cardiovascular system resemble those of captopril and might be considered as a favourable profile for the antihypertensive agent. PMID:3513779

Takeyama, K; Minato, H; Nakatsuji, K; Suzuki, H; Nose, I; Oka, M; Hosoki, K; Hatano, N; Kadokawa, T

1986-01-01

324

Amelioration of central cardiovascular regulatory dysfunction by tropomyocin receptor kinase B in a mevinphos intoxication model of brain stem death  

PubMed Central

BACKGROUND AND PURPOSE Little information exists on the mechanisms that precipitate brain stem death, the legal definition of death in many developed countries. We investigated the role of tropomyocin receptor kinase B (TrkB) and its downstream signalling pathways in the rostral ventrolateral medulla (RVLM) during experimental brain stem death. EXPERIMENTAL APPROACH An experimental model of brain stem death that employed microinjection of the organophosphate insecticide mevinphos bilaterally into the RVLM of Sprague–Dawley rats was used, in conjunction with cardiovascular, pharmacological and biochemical evaluations. KEY RESULTS A significant increase in TrkB protein, phosphorylation of TrkB at Tyr516 (pTrkBY516), Shc at Tyr317 (pShcY317) or ERK at Thr202/Tyr204, or Ras activity in RVLM occurred preferentially during the pro-life phase of experimental brain stem death. Microinjection bilaterally into RVLM of a specific TrkB inhibitor, K252a, antagonized those increases. Pretreatment with anti-pShcY317 antiserum, Src homology 3 binding peptide (Grb2/SOS inhibitor), farnesylthioacetic acid (Ras inhibitor), manumycin A (Ras inhibitor) or GW5074 (Raf-1 inhibitor) blunted the preferential augmentation of Ras activity or ERK phosphorylation in RVLM and blocked the up-regulated NOS I/protein kinase G (PKG) signalling, the pro-life cascade that sustains central cardiovascular regulation during experimental brain stem death. CONCLUSIONS AND IMPLICATIONS Activation of TrkB, followed by recruitment of Shc/Grb2/SOS adaptor proteins, leading to activation of Ras/Raf-1/ERK signalling pathway plays a crucial role in ameliorating central cardiovascular regulatory dysfunction via up-regulation of NOS I/PKG signalling cascade in the RVLM in brain stem death. These findings provide novel information for developing therapeutic strategies against this fatal eventuality.

Chan, SHH; Chan, JYH; Hsu, KS; Li, FCH; Sun, EYH; Chen, WL; Chang, AYW

2011-01-01

325

Fatigue life assessment of cardiovascular balloon-expandable stents: a two-scale plasticity-damage model approach.  

PubMed

Cardiovascular disease has become a major global health care problem in the present decade. 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, as a result of the high number of cyclic loads these devices are subjected to in vivo, numerical approaches for fatigue life assessment of stents has gained special interest in the engineering community. Numerical fatigue predictions can be used to modify the design and prevent failure, without making and testing numerous physical devices, thus preventing from undesired fatigue failures. This work presents a fatigue life numerical method for the analysis of cardiovascular balloon-expandable stainless steel stents. The method is based on a two-scale continuum damage mechanics model in which both plasticity and damage mechanisms are assumed to take place at a scale smaller than the scale of the representative volume element. The fatigue failure criterion is based on the Soderberg relation. The method is applied to the fatigue life assessment of both PalmazShatz and Cypher stent designs. Validation of the method is performed through comparison of the obtained numerical results with some experimental results available for the PalmazShatz stent design. The present study gives also possible directions for future research developments in the framework of the numerical fatigue life assessment of real balloon-expandable stents. PMID:23032428

Argente dos Santos, H A F; Auricchio, F; Conti, M

2012-11-01

326

MLS: Airplane system modeling  

NASA Technical Reports Server (NTRS)

Analysis, modeling, and simulations were conducted as part of a multiyear investigation of the more important airplane-system-related items of the microwave landing system (MLS). Particular emphasis was placed upon the airplane RF system, including the antenna radiation distribution, the cabling options from the antenna to the receiver, and the overall impact of the airborne system gains and losses upon the direct-path signal structure. In addition, effort was expended toward determining the impact of the MLS upon the airplane flight management system and developing the initial stages of a fast-time MLS automatic control system simulation model. Results ot these studies are presented.

Thompson, A. D.; Stapleton, B. P.; Walen, D. B.; Rieder, P. F.; Moss, D. G.

1981-01-01

327

Cardiovascular performance with E. coli challenges in a canine model of human sepsis  

SciTech Connect

The authors investigated cardiovascular dysfunction by injecting lethal and nonlethal bacterial challenges into conscious dogs. E coli bacteria of varying numbers were placed in a peritoneal clot. Cardiovascular function was studied with simultaneous radionuclide scans and thermodilution cardiac outputs. In surviving animals, the number of bacteria in the clot increased as the corresponding systolic cardiac function decreased. Cardiac function was measured by left ventricular (LV) ejection fraction (EF) and LV function curves. Furthermore, the diastolic volume-pressure relationship of survivors shifted progressively to the right. This increase in LV size was associated with maintenance of measures of cardiac performance at similar levels. Death occurred only in the group with the highest bacterial dose. Compared with survivors receiving the same number of bacterial, nonsurvivors had a decrease in LV size, a leftward shift in LV diastolic volume-pressure relationship, and a decrease in both LVSWI and SVI. Data from survivors suggest that increasing the number of bacteria produces changes in myocardial compliance and contractility. These changes increase LV size (preload), a major determinant of cardiac performance that possibility enhances survival.

Natanson, C.; Danner, R.L.; Fink, M.P.; MacVittie, T.J.; Walker, R.I.; Conklin, J.J.; Parrillo, J.E. (National Institutes of Health, Bethesda, MD (USA) Naval Medical Research Institute and Armed Forces Radiobiology Research Institute, Bethesda, MD (USA) Univ. of Massachusetts Medical Center, Worcester (USA))

1988-03-01

328

Artificial neural interfaces for bionic cardiovascular treatments.  

PubMed

An artificial nerve, in the broad sense, may be conceptualized as a physical and logical interface system that reestablishes the information traffic between the central nervous system and peripheral organs. Studies on artificial nerves targeting the autonomic nervous system are in progress to explore new treatment strategies for several cardiovascular diseases. In this article, we will review our research targeting the autonomic nervous system to treat cardiovascular diseases. First, we identified the rule for decoding native sympathetic nerve activity into a heart rate using transfer function analysis, and established a framework for a neurally regulated cardiac pacemaker. Second, we designed a bionic baroreflex system to restore the baroreflex buffering function using electrical stimulation of the celiac ganglion in a rat model of orthostatic hypotension. Third, based on the hypothesis that autonomic imbalance aggravates chronic heart failure, we implanted a neural interface into the right vagal nerve and demonstrated that intermittent vagal stimulation significantly improved the survival rate in rats with chronic heart failure following myocardial infarction. Although several practical problems need to be resolved, such as those relating to the development of electrodes feasible for long-term nerve activity recording, studies of artificial neural interfaces with the autonomic nervous system have great possibilities in the field of cardiovascular treatment. We expect further development of artificial neural interfaces as novel strategies to cope with cardiovascular diseases resistant to conventional therapeutics. PMID:19330500

Kawada, Toru; Sugimachi, Masaru

2009-01-01

329

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

330

Integrated Workforce Modeling System  

NASA Technical Reports Server (NTRS)

There are several computer-based systems, currently in various phases of development at KSC, which encompass some component, aspect, or function of workforce modeling. These systems may offer redundant capabilities and/or incompatible interfaces. A systems approach to workforce modeling is necessary in order to identify and better address user requirements. This research has consisted of two primary tasks. Task 1 provided an assessment of existing and proposed KSC workforce modeling systems for their functionality and applicability to the workforce planning function. Task 2 resulted in the development of a proof-of-concept design for a systems approach to workforce modeling. The model incorporates critical aspects of workforce planning, including hires, attrition, and employee development.

Moynihan, Gary P.

2000-01-01

331

Cholesterol-Secreting and Statin-Responsive Hepatocytes from Human ES and iPS Cells to Model Hepatic Involvement in Cardiovascular Health  

PubMed Central

Hepatocytes play a central and crucial role in cholesterol and lipid homeostasis, and their proper function is of key importance for cardiovascular health. In particular, hepatocytes (especially periportal hepatocytes) endogenously synthesize large amounts of cholesterol and secrete it into circulating blood via apolipoprotein particles. Cholesterol-secreting hepatocytes are also the clinically-relevant cells targeted by statin treatment in vivo. The study of cholesterol homeostasis is largely restricted to the use of animal models and immortalized cell lines that do not recapitulate those key aspects of normal human hepatocyte function that result from genetic variation of individuals within a population. Hepatocyte-like cells (HLCs) derived from human embryonic and induced pluripotent stem cells can provide a cell culture model for the study of cholesterol homeostasis, dyslipidemias, the action of statins and other pharmaceuticals important for cardiovascular health. We have analyzed expression of core components for cholesterol homeostasis in untreated human iPS cells and in response to pravastatin. Here we show the production of differentiated cells resembling periportal hepatocytes from human pluripotent stem cells. These cells express a broad range of apolipoproteins required for secretion and elimination of serum cholesterol, actively secrete cholesterol into the medium, and respond functionally to statin treatment by reduced cholesterol secretion. Our research shows that HLCs derived from human pluripotent cells provide a robust cell culture system for the investigation of the hepatic contribution to human cholesterol homeostasis at both cellular and molecular levels. Importantly, it permits for the first time to also functionally assess the impact of genetic polymorphisms on cholesterol homeostasis. Finally, the system will also be useful for mechanistic studies of heritable dyslipidemias, drug discovery, and investigation of modes of action of cholesterol-modulatory drugs.

Krueger, Winfried H.; Tanasijevic, Borko; Barber, Vanessa; Flamier, Anthony; Gu, Xinsheng; Manautou, Jose; Rasmussen, Theodore P.

2013-01-01

332

Cardiovascular system in larval zebrafish responds to developmental hypoxia in a family specific manner  

PubMed Central

Background Genetic and environmental variation are both known to influence development. Evolution of a developmental response that is optimized to the environment (adaptive plasticity) requires the existence of genetic variation for that developmental response. In complex traits composed of integrated sets of subsidiary traits, the adaptive process may be slowed by the existence of multiple possible integrated responses. This study tests for family (sibship) specific differences in plastic response to hypoxia in an integrated set of cardiovascular traits in zebrafish. Results Cardiac output, which is the integrated product of several subsidiary traits, varied highly significantly between families, and families differed significantly in the degree and direction of response to developmental oxygen level. The cardiac output response to oxygen environment was entirely family specific with no significant overall trend due to oxygen level. Constituent physiological variables that contribute to cardiac output all showed significant family specific response to hypoxia. Traits that were not directly related to cardiac output, such as arterial and venous diameter, and red blood cell velocities did not respond to hypoxia in a family specific manner. Conclusion Zebrafish families vary in their plastic response to hypoxia. Genetic variation in plastic response to hypoxia may therefore provide the basic ingredient for adaptation to a variable environment. Considerable variation in the degree of familial response to hypoxia exists between different cardiovascular traits that may contribute to cardiac output. It is possible that the integration of several subsidiary traits into cardiac output allows the maintenance of genetic variance in cardiac response.

Moore, Francisco B-G; Hosey, Michelle; Bagatto, Brian

2006-01-01

333

Generic User Modeling Systems  

Microsoft Academic Search

The paper reviews the development of generic user modeling systems over the past twenty years. It describes their purposes, their services within user-adaptive systems, and the different design requirements for research prototypes and commerciallydeployed servers. It dis- cusses the architectures that have been explored so far, namely shell systems that form part oftheapplication,centralserversystemsthatcommunicatewithseveralapplications,andpossible future user modeling agents that physically follow

Alfred Kobsa

2001-01-01

334

Cardiovascular Pharmacology of Cannabinoids  

PubMed Central

Cannabinoids and their synthetic and endogenous analogs affect a broad range of physiological functions, including cardiovascular variables, the most important component of their effect being profound hypotension. The mechanisms of the cardiovascular effects of cannabinoids in vivo are complex and may involve modulation of autonomic outflow in both the central and peripheral nervous systems as well as direct effects on the myocardium and vasculature. Although several lines of evidence indicate that the cardiovascular depressive effects of cannabinoids are mediated by peripherally localized CB1 receptors, recent studies provide strong support for the existence of as-yet-undefined endothelial and cardiac receptor(s) that mediate certain endocannabinoid-induced cardiovascular effects. The endogenous cannabinoid system has been recently implicated in the mechanism of hypotension associated with hemorrhagic, endotoxic, and cardiogenic shock, and advanced liver cirrhosis. Furthermore, cannabinoids have been considered as novel antihypertensive agents. A protective role of endocannabinoids in myocardial ischemia has also been documented. In this chapter, we summarize current information on the cardiovascular effects of cannabinoids and highlight the importance of these effects in a variety of pathophysiological conditions.

Pacher, P.; Batkai, S.; Kunos, G.

2008-01-01

335

Effects of Nimesulide, a Selective COX-2 Inhibitor, on Cardiovascular Function in 2 Rat Models of Diabetes.  

PubMed

: Cyclooxygenase-2 (COX-2) has been found to be activated in diabetes. We investigated whether nimesulide (selective COX-2 inhibitor) alters cardiovascular responses to adrenaline in 2 rat models of diabetes. Wistar rats (5-week old) were continuously fed a normal or high-fructose diet (60% of caloric intake). At week 2, half of the rats in each diet regimen were given streptozotocin (STZ) (60 mg/kg, intravenously). At week 6, cardiovascular effects of adrenaline (6 and 16 × 10 mol·kg·min, intravenously) were measured in 4 groups of thiobutabarbital-anesthetized rats (control, fructose, STZ, and fructose-streptozotocin [F-STZ]) before and after the injection of nimesulide (3 mg/kg, intravenously). Both the STZ and F-STZ groups exhibited hyperglycemia and significantly (P < 0.05) reduced left ventricular contractility, mean arterial pressure, arterial and venous resistance, and mean circulatory filling pressure (index of venous tone) responses to adrenaline, relative to the control and fructose groups. Nimesulide did not affect responses in the control and fructose groups but increased the venous and, to a less extent, arterial constriction to adrenaline in both the groups of diabetic rats. The cardiac contractile responses, however, were not altered after nimesulide treatment. The results show that nimesulide partially restored arterial and venous constriction to adrenaline in rats with STZ- and F-STZ-induced diabetes. PMID:24621649

Leung, Joanne Y T; Pang, Catherine C Y

2014-07-01

336

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

337

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.

Raman, Venkatesh K.; Lederman, Robert J.

2008-01-01

338

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

339

Analysis of Maternal and Fetal Cardiovascular Systems During Hyperglycemic Pregnancy in the Non-Obese Diabetic Mouse  

PubMed Central

Pre-conception or gestationally-induced diabetes increases morbidities and elevates long-term cardiovascular disease risks in women and their children. Spontaneously hyperglycemic (d)-NOD/ShiLtJ females, a type 1 diabetes model, develop bradycardia and hypotension after midpregnancy compared with normoglycemic, age and gestation day (gd)-matched controls (c-NOD). We hypothesized that onset of the placental circulation at gd9–10 and rapid fetal growth from gd14 correlate with aberrant hemodynamic outcomes in d-NOD females. To develop further gestational time course correlations between maternal cardiac and renal parameters, high-frequency ultrasonography was applied to virgin and gd8–16 d- and c-NODs. Cardiac output and left ventricular (LV) mass increased in c- but not d-NODs. Ultrasound and postmortem histopathology showed overall greater LV dilation in d- than c-NOD mice in mid-late gestation. These changes suggest blunted remodeling and altered functional adaptation of d-NOD hearts. Umbilical cord ultrasounds revealed lower fetal heart rates from gd12 and lower umbilical flow velocities at gd14 and 16 in d- versus c-NOD pregnancies. From gd14–16, d-NOD fetal losses exceeded those of c-NOD. Similar aberrant responses in human diabetic pregnancies may elevate postpartum maternal and child cardiovascular risk, particularly if mothers lack adequate prenatal care or have poor glycemic control over gestation.

Aasa, Kristiina L.; Kwong, Kenneth K.; Adams, Michael A.; Croy, B. Anne

2013-01-01

340

Regulation of Cell Physiology and Pathology by Protein S-Glutathionylation: Lessons Learned from the Cardiovascular System  

PubMed Central

Abstract Significance: Reactive oxygen and nitrogen species contributing to homeostatic regulation and the pathogenesis of various cardiovascular diseases, including atherosclerosis, hypertension, endothelial dysfunction, and cardiac hypertrophy, is well established. The ability of oxidant species to mediate such effects is in part dependent on their ability to induce specific modifications on particular amino acids, which alter protein function leading to changes in cell signaling and function. The thiol containing amino acids, methionine and cysteine, are the only oxidized amino acids that undergo reduction by cellular enzymes and are, therefore, prime candidates in regulating physiological signaling. Various reports illustrate the significance of reversible oxidative modifications on cysteine thiols and their importance in modulating cardiovascular function and physiology. Recent Advances: The use of mass spectrometry, novel labeling techniques, and live cell imaging illustrate the emerging importance of reversible thiol modifications in cellular redox signaling and have advanced our analytical abilities. Critical Issues: Distinguishing redox signaling from oxidative stress remains unclear. S-nitrosylation as a precursor of S-glutathionylation is controversial and needs further clarification. Subcellular distribution of glutathione (GSH) may play an important role in local regulation, and targeted tools need to be developed. Furthermore, cellular redundancies of thiol metabolism complicate analysis and interpretation. Future Directions: The development of novel pharmacological analogs that specifically target subcellular compartments of GSH to promote or prevent local protein S-glutathionylation as well as the establishment of conditional gene ablation and transgenic animal models are needed. Antioxid. Redox Signal. 16, 524–542.

Pimentel, David; Haeussler, Dagmar Johanna; Matsui, Reiko; Burgoyne, Joseph Robert; Cohen, Richard Alan

2012-01-01

341

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.

Pinho, Brigida R; Santos, Miguel M; Fonseca-Silva, Anabela; Valentao, Patricia; Andrade, Paula B; Oliveira, Jorge M A

2013-01-01

342

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

343

MicroRNAs: potential therapeutic targets in diabetic complications of the cardiovascular and renal systems.  

PubMed

Diabetes mellitus is a serious health problem that can lead to several pathological complications in numerous organs and tissues. The most important and most prevalent organs affected by this disease are the heart and the kidneys, and these complications are the major causes of death in patients with diabetes. MicroRNAs (miRNAs), short non-coding RNAs, have been found to be functionally important in the regulation of several pathological processes, and they are emerging as an important therapeutic tool to avoid the complications of diabetes mellitus. This review summarizes the knowledge on the effects of miRNAs in diabetes. The use of miRNAs in diabetes from a clinical perspective is also discussed, focusing on their potential role to repair cardiovascular and renal complications. PMID:24837225

Figueira, M F; Monnerat-Cahli, G; Medei, E; Carvalho, A B; Morales, M M; Lamas, M E; da Fonseca, R N; Souza-Menezes, J

2014-07-01

344

Three-year stability of cardiovascular and autonomic nervous system responses to psychological stress.  

PubMed

Chronically heightened physiological reactivity to or delayed recovery from stress may contribute to cardiovascular (CV) risk and mortality. Long-term stability of physiological stress responses has received little attention. Our objectives were to evaluate the 3-year stability of reactivity and recovery change scores across CV and autonomic parameters and assess whether sex and age moderate stability. A total of 134 healthy participants underwent two laboratory stress protocols, including four 5-min interpersonal stressors, each followed by a 5-min recovery period. Heart rate (HR), blood pressure (BP), and HR variability (high frequency, low frequency, very low frequency [VLF]) were obtained. Spearman rank correlations and linear regressions were performed. Significant correlations emerged for all physiological measures except diastolic BP and VLF recovery. No significant sex or age differences were found. Stress responses represent stable individual traits little affected by sex or age. PMID:24853995

Dragomir, Anda I; Gentile, Christina; Nolan, Robert P; D'Antono, Bianca

2014-09-01

345

Microalbuminuria and cardiovascular risk.  

PubMed

Microalbuminuria is a marker for generalized vascular dysfunction. Its prevalence in United States and European general population surveys ranges from 6% to 10%. Increased risk for cardiovascular morbidity and mortality begins with albumin excretion rates that are well within normal limits. Although microalbuminuria interacts with the traditional cardiovascular risk factors, it has an independent relationship to renal and cardiovascular outcomes. For example, microalbuminuria doubles the risk for a cardiovascular event in patients with type 2 diabetes mellitus even after adjusting for the usual risk factors. Elevated rates of urinary albumin excretion predict target organ damage, notably renal disease, but are also related to left ventricular dysfunction, stroke, and myocardial infarction. Screening for microalbuminuria, which is recommended by several expert committees and associations, has become a readily accessible procedure. Screening can give clinicians prognostic information concerning cardiovascular risk and assist in guiding therapy. The goal of treatment is to prevent progression of, and even to reverse, microalbuminuria. Abundant evidence demonstrates that antihypertensive therapy is an important key to the control of urinary albumin excretion, and blockade of the renin-angiotensin system (with angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers) is the treatment of choice. These drugs have successfully halted or delayed the progression to nephropathy and have reversed elevated rates of albumin excretion to normal values, even when blood pressure reduction has been minimal. PMID:15485765

Karalliedde, Janaka; Viberti, Giancarlo

2004-10-01

346

Automated evaluation of electronic discharge notes to assess quality of care for cardiovascular diseases using Medical Language Extraction and Encoding System (MedLEE)  

Microsoft Academic Search

The objective of this study was to develop and validate an automated acquisition system to assess quality of care (QC) measures for cardiovascular diseases. This system combining searching and retrieval algorithms was designed to extract QC measures from electronic discharge notes and to estimate the attainment rates to the current standards of care. It was developed on the patients with

Jung-Hsien Chiang; Jou-Wei Lin; Chen-Wei Yang

2010-01-01

347

System Effectiveness Model Formulation  

SciTech Connect

Evaluation of system effectiveness has numerous pitfalls. System objectives may be poorly defined, may shift during the system life or may be hard to quantify. Further, individual perceptions of the quantifications may differ. Whatever the cause, system effectiveness has been an elusive term to quantitatively define. The proposed model presents a quantitative system effectiveness model and establishes a utilitarian approach for its use with the illustrative application to a nuclear safeguards system. The model uses the Type I and Type II statistical error rates as input to the component or subsystem effectiveness calculation which, when combined using a utilitarian methodology, quantify the overall system effectiveness. The methodology will use a survey of expert judgment to determine the relative importance of the individual subsystems through a statistically designed web survey. The web based survey will be available to nuclear material protection, control, and accounting experts attending the 2008 INMM conference. This model and methodology will provide a repeatable quantifiable measure for any system but in this case a simple safeguards system is used as an example.

Coates, Cameron W [ORNL; Jackson, Denise F [ORNL

2008-01-01

348

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

PubMed Central

Aims To describe change in physical activity over 1 year and associations with change in cardiovascular disease risk factors in a population with screen-detected Type 2 diabetes. Methods Eight hundred and sixty-seven individuals with screen-detected diabetes underwent measurement of self-reported physical activity, cardiovascular disease risk factors and modelled cardiovascular disease risk at baseline and 1 year (n = 736) in the ADDITION-Cambridge trial. Multiple linear regression was used to quantify the association between change in different physical activity domains and cardiovascular disease risk factors at 1 year. Results There was no change in self-reported physical activity over 12 months. Even relatively large changes in physical activity were associated with relatively small changes in cardiovascular disease risk factors after allowing for changes in self-reported medication and diet. For every 30 metabolic equivalent-h increase in recreational activity (equivalent to 10 h/brisk walking/week), there was an average reduction of 0.1% in HbA1c in men (95% CI ?0.15 to ?0.01, P = 0.021) and an average reduction of 2 mmHg in systolic blood pressure in women (95% CI ?4.0 to ?0.05, P = 0.045). Conclusions Few associations were observed between change in different physical activity domains and cardiovascular disease risk factors in this trial cohort. Cardiovascular disease risk reduction appeared to be driven largely by factors other than changes in self-reported physical activity in the first year following diagnosis.

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

2013-01-01

349

Cardiovascular effects of tadalafil  

Microsoft Academic Search

To determine the effects of tadalafil on the cardiovascular system, safety assessments were performed on a database of >4,000 subjects who received tadalafil in >60 clinical pharmacology, phase 2, phase 3, and open-label studies. In healthy subjects, tadalafil resulted in small changes in blood pressure, which are not believed to be clinically relevant. Daily administration of tadalafil 20 mg for

Robert A Kloner; Malcolm Mitchell; Jeffrey T Emmick

2003-01-01

350

and cardiovascular health  

Microsoft Academic Search

A vast number of pharmacological and clinical studies indicate that Pycnogenol ® , a standardised extract of French maritime pine bark (Pinus pinaster), bears various favourable health benefits for the cardiovascular system. Pycnogenol is primarily composed of phenolic acids, derivatives of benzoic and cinnamic acid, and procyanidins. The latter are biopolymers of catechin and epicatechin subunits, which are recognised as

Ronald R Watson

2003-01-01

351

Multiscale Cloud System Modeling  

NASA Technical Reports Server (NTRS)

The central theme of this paper is to describe how cloud system resolving models (CRMs) of grid spacing approximately 1 km have been applied to various important problems in atmospheric science across a wide range of spatial and temporal scales and how these applications relate to other modeling approaches. A long-standing problem concerns the representation of organized precipitating convective cloud systems in weather and climate models. Since CRMs resolve the mesoscale to large scales of motion (i.e., 10 km to global) they explicitly address the cloud system problem. By explicitly representing organized convection, CRMs bypass restrictive assumptions associated with convective parameterization such as the scale gap between cumulus and large-scale motion. Dynamical models provide insight into the physical mechanisms involved with scale interaction and convective organization. Multiscale CRMs simulate convective cloud systems in computational domains up to global and have been applied in place of contemporary convective parameterizations in global models. Multiscale CRMs pose a new challenge for model validation, which is met in an integrated approach involving CRMs, operational prediction systems, observational measurements, and dynamical models in a new international project: the Year of Tropical Convection, which has an emphasis on organized tropical convection and its global effects.

Tao, Wei-Kuo; Moncrieff, Mitchell W.

2009-01-01

352

The Role of Decision Support System (DSS) in Prevention of Cardiovascular Disease: A Systematic Review and Meta-Analysis  

PubMed Central

Background The potential role of DSS in CVD prevention remains unclear as only a few studies report on patient outcomes for cardiovascular disease. Methods and Results A systematic review and meta-analysis of randomised controlled trials and observational studies was done using Medline, Embase, Cochrane Library, PubMed, Amed, CINAHL, Web of Science, Scopus databases; reference lists of relevant studies to 30 July 2011; and email contact with experts. The primary outcome was prevention of cardiovascular disorders (myocardial infarction, stroke, coronary heart disease, peripheral vascular disorders and heart failure) and management of hypertension owing to decision support systems, clinical decision supports systems, computerized decision support systems, clinical decision making tools and medical decision making (interventions). From 4116 references ten studies met our inclusion criteria (including 16,312 participants). Five papers reported outcomes on blood pressure management, one paper on heart failure, two papers each on stroke, and coronary heart disease. The pooled estimate for CDSS versus control group differences in SBP (mm of Hg) was - 0.99 (95% CI ?3.02 to 1.04 mm of Hg; I2?=?0; p?=?0.851). Conclusions DSS show an insignificant benefit in the management and control of hypertension (insignificant reduction of SBP). The paucity of well-designed studies on patient related outcomes is a major hindrance that restricts interpretation for evaluating the role of DSS in secondary prevention. Future studies on DSS should (1) evaluate both physician performance and patient outcome measures (2) integrate into the routine clinical workflow with a provision for decision support at the point of care.

Anchala, Raghupathy; Chowdhury, Rajiv; Sanderson, Jean; Johnson, Laura; Blanco, Patricia; Prabhakaran, Dorairaj; Franco, Oscar H.

2012-01-01

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

Jones, D. R.

1973-01-01

354

Efficient computation of interacting model systems.  

PubMed

Physiological processes in the human body can be predicted by mathematical models. Medical Decision Support Systems (MDSS) might exploit these predictions when optimizing therapy settings. In critically ill patients depending on mechanical ventilation, these predictions should also consider other organ systems of the human body. In a previously presented framework we combine elements of three model families: respiratory mechanics, cardiovascular dynamics and gas exchange. Computing combinations of moderately complex submodels showed to be computationally costly thus limiting the applicability of those model combinations in an MDSS. A decoupled computing approach was therefore developed, which enables individual evaluation of every submodel. Direct model interaction is not possible in separate calculations. Therefore, interface signals need to be substituted by estimates. These estimates are iteratively improved by increasing model detail in every iteration exploiting the hierarchical structure of the implemented model families. Simulation error converged to a minimum after three iterations. Maximum simulation error showed to be 1.44% compared to the original common coupled computing approach. Simulation error was found to be below measurement noise generally found in clinical data. Simulation time was reduced by factor 34 using one iteration and factor 13 using three iterations. Following the proposed calculation scheme moderately complex model combinations seem to be applicable for model based decision support. PMID:23395682

Kretschmer, J; Schranz, C; Knöbel, C; Wingender, J; Koch, E; Möller, K

2013-06-01

355

Optical systems integrated modeling  

Microsoft Academic Search

An integrated modeling capability that provides the tools by which entire optical systems and instruments can be simulated and optimized is a key technology development, applicable to all mission classes, especially astrophysics. Many of the future missions require optical systems that are physically much larger than anything flown before and yet must retain the characteristic sub-micron diffraction limited wavefront accuracy

Robert R. Shannon; Robert A. Laskin; Si Brewer; Chris Burrows; Harlan Epps; Garth Illingworth; Dietrich Korsch; B. Martin Levine; Vini Mahajan; Chuck Rimmer

1992-01-01

356

Is the dog a useful model for accelerated calcification study of cardiovascular bioprostheses?  

PubMed

Chitosan posttreatment has been shown to be effective in prevention of calcification of the glutaraldehyde treated bovine pericardium when implanted subdermally in rats for 12 weeks. The efficacy of chitosan posttreatment in complete calcium mitigation of the glutaraldehyde treated porcine aortic valves implanted in the right side of the heart in dogs was well-documented in our previous study. In this study, an attempt has been made to evaluate the merit of the chitosan posttreatment in prevention of calcification of the glutaraldehyde (GA) treated porcine aortic valved conduits in the systemic circulation in dogs for a period of 5 months. Eleven mongrel dogs underwent left thoracotomy. Porcine aortic valved conduits treated with 0.625% GA (n = 5) and GA-chitosan (n = 6) were implanted in the descending thoracic aortas of the dogs for 5 months. Gross histological observations showed no calcification in either the 0.625% GA treated or in the GA-chitosan treated valved conduits at 5 months. This was confirmed by results of quantitative analyses for calcium in each explant. There was no significant difference in calcium content between the GA only (Ca, 0.43 +/- 0.26 mg/g) and GA-chitosan treated (Ca, 0.51 +/- 0.19 mg/g; p = 0.5959) valved conduits. This study suggests that the dog is not a suitable model for evaluating the efficacy of a calcium mitigating agent in bioprostheses implanted in systemic circulation. PMID:9129770

Chanda, J; Kuribayashi, R; Abe, T; Sekine, S; Shibata, Y; Yamagishi, I

1997-05-01

357

[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

358

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 B.

359

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

360

Role of endocannabinoid 2-arachidonoylglycerol in the physiology and pathophysiology of the cardiovascular system.  

PubMed

Cannabinoids, the active ingredients of Cannabis sativa var. indica, have been used by humans as recreational and therapeutic agents for thousands of years. This group of substances also includes synthetic ligands and, synthesized in the body of humans and animals, endocannabinoids. The best known compound classified as an endogenous cannabinoid is anandamide. However, recent studies show that another compound of this group, 2-arachidonoylglycerol (2-AG), also performs many important functions in the organism. 2-Arachidonoylglycerol plays an important role in the regulation of the circulatory system via direct and/or indirect, through their metabolites, effects on blood vessels and/or heart. Accumulating evidence reveals that 2-AG is involved in the pathogenesis of various shocks and atherosclerosis. Thus, it may be a novel attractive therapeutic target. However, because of rapid metabolism and opposite effects dependent on the experimental model, the function of 2-AG still remains to be established. PMID:24934539

Karabowicz, Piotr; Grz?da, Emilia; Baranowska-Kuczko, Marta; Malinowska, Barbara

2014-01-01

361

Worksite wellness for the primary and secondary prevention of cardiovascular disease in Japan: the current delivery system and future directions.  

PubMed

In the Japanese workplace, employers are required to provide annual health checkups for workers in accordance with the "Industrial Safety and Health Law," which also mandates that an occupational physician be assigned to companies employing at least 50 workers. The annual medical examination includes testing for the early detection of cardiovascular risk factors such as hypertension, dyslipidemia, diabetes, and the metabolic syndrome. This approach has successfully contributed to the extremely low incidence of coronary artery disease among Japanese workers. However, problems such as poor health and the low rate of participation in health checkups among small-scale companies still persist. Furthermore, although most wellness delivery systems in Japan employ strategies targeting high-risk individuals, instituting a strategy addressing the broader population irrespective of screening may be effective in reducing disease risk in the overall population. As a future direction, we should therefore develop practical methods for implementing a population strategy. PMID:24607016

Okamura, Tomonori; Sugiyama, Daisuke; Tanaka, Taichiro; Dohi, Seitaro

2014-01-01

362

Role of Systemic Markers in Periodontal Diseases: A Possible Inflammatory Burden and Risk Factor for Cardiovascular Diseases?  

PubMed Central

Background: Periodontitis is a local inflammatory process mediating destruction of periodontium triggered by bacterial insult leading to systemic inflammatory mayhem in the host. Epidemiologically, it has been modestly associated with cardiovascular diseases (CVD) with elevated acute-phase reactant C-reactive protein (CRP) and rheological variables such as total leukocyte count and differential leukocyte count (TLC and DLC), which are potential predictors of CVD. Aim: The aim of this study was to investigate the serum CRP level, leukocyte count in chronic periodontitis patients and their relation to the severity of chronic periodontitis. Subjects and Methods: This cross-sectional study comprised 30 subjects, of which 20 were diagnosed as chronic periodontitis based on the Gingival index, probing depth and clinical attachment levels and 10 healthy subjects as controls. Following, which peripheral blood samples were drawn and serum CRP, TLC and DLC were quantified using the turbidimetric immunoassay. Data was analyzed using Intercooled Stata 9.2 version, (Stata corporation, LP, USA) ANOVA, Mann Whitney U test and Newman-Keuls post hoc procedures. P values less than) 0.05 were considered as significant Results: The mean serum CRP levels were statistically significant (P < 0.05) in severe and moderate periodontitis subjects when compared with healthy controls. Leukocytes were significantly elevated in severe periodontitis compared with moderate periodontitis and controls; this finding was primarily explained by the increase in number of neutrophils. Conclusion: The increased serum CRP levels and neutrophils in chronic periodontitis subjects suggest an addition to the inflammatory burden of the individual potentially striking toward an increasing risk for cardiovascular events. Further research is needed to determine the specificity of these markers and their role in the inflammatory burden of one's systemic health.

Kalburgi, V; Sravya, L; Warad, S; Vijayalaxmi, K; Sejal, P; Hazeil, DJ

2014-01-01

363

Adeno-associated virus vectors as therapeutic and investigational tools in the cardiovascular system.  

PubMed

The use of vectors based on the small parvovirus adeno-associated virus has gained significant momentum during the past decade. Their high efficiency of transduction of postmitotic tissues in vivo, such as heart, brain, and retina, renders these vectors extremely attractive for several gene therapy applications affecting these organs. Besides functional correction of different monogenic diseases, the possibility to drive efficient and persistent transgene expression in the heart offers the possibility to develop innovative therapies for prevalent conditions, such as ischemic cardiomyopathy and heart failure. Therapeutic genes are not only restricted to protein-coding complementary DNAs but also include short hairpin RNAs and microRNA genes, thus broadening the spectrum of possible applications. In addition, several spontaneous or engineered variants in the virus capsid have recently improved vector efficiency and expanded their tropism. Apart from their therapeutic potential, adeno-associated virus vectors also represent outstanding investigational tools to explore the function of individual genes or gene combinations in vivo, thus providing information that is conceptually similar to that obtained from genetically modified animals. Finally, their single-stranded DNA genome can drive homology-directed gene repair at high efficiency. Here, we review the main molecular characteristics of adeno-associated virus vectors, with a particular view to their applications in the cardiovascular field. PMID:24855205

Zacchigna, Serena; Zentilin, Lorena; Giacca, Mauro

2014-05-23

364

Phase dependencies between longitudinal corneal apex displacement of human eye and cardiovascular system  

NASA Astrophysics Data System (ADS)

Intraocular pressure (IOP) varies quasi-periodically due to blood pulsation in vessels inside the eye globe. This variations cause the eye deformations and displacements of the outer surface of the eye. The aim of this paper is to calculate the correlation between longitudinal corneal apex displacement and cardiovascular activity. Using ultrasound transducer at sampling frequency of 100Hz we have measured longitudinal corneal apex displacement (LCAD) of the left eye for 5 subjects. Synchronically we have registered ECG and blood pulsation signals at the same sampling frequency. Cross-correlation function was applied to investigate dependencies between these signals. To find time shift between LCAD and ECG or pulse, the time window of 3 seconds length have been chosen from all signals and had been shifting with the step of 0.01 seconds from 0 to 7s. For each shift the cross-correlation function and its extrema were calculated in the window area. We have obtained information about extrema position of cross-correlation function and its stability in time for particular subjects. The time shift between LCAD and ECG or pulse is individual feature of each subject. Such calculations may lead us to better understanding of pulse propagation in human eye and creation a non invasive method of eye hemodynamics and ocular diagnosis.

Danielewska, M.; Kowalska, M.; Kasprzak, H.

2008-12-01

365

Use of a Marginal Structural Model to Determine the Effect of Aspirin on Cardiovascular Mortality in the Physicians' Health Study  

Microsoft Academic Search

The 1982-1988 aspirin component of the Physicians' Health Study, a randomized trial of aspirin and ?- carotene in primary prevention of cardiovascular disease and cancer among 22,071 US male physicians, was terminated early primarily because of a statistically extreme 44% reduction in first myocardial infarction, with inadequate precision and no apparent effect on the primary endpoint, cardiovascular death. Because of

Nancy R. Cook; Stephen R. Cole; Charles H. Hennekens

366

Fluorophore-mediated, fiber-optic, multi-analyte, immunosensing system for rapid diagnosis and prognosis of cardiovascular diseases  

NASA Astrophysics Data System (ADS)

A prototype of a fiber-optic, multi-analyte, immunobiosensing system was developed to simultaneously quantify disease-representing biomarkers in blood plasma. This system was for simultaneous quantification of two different groups of multi-biomarkers related to cardiovascular diseases (CVD): anticoagulants (protein C, protein S, antithrombin III, and plasminogen) for deficiency diagnosis; and cardiac markers (B-type natriuretic peptide, cardiac troponin I, myoglobin, and C-reactive protein) for coronary heart disease diagnosis. As an initial effort towards the development of a disposable and easy-to-use sensing cartridge as a rapid diagnostic tool for CVD related diseases, a prototype of a flow control system was also developed to automatically perform simultaneous four-analyte quantification. Currently, the system is capable of quantifying the multiple anticoagulants in their clinically significant sensing ranges within 5 minutes, at an average signal-to-noise (S/N) ratio of 25. A simultaneous assay of the four cardiac markers can be performed within 10 min, at an average S/N ratio of 20. When this highly portable multi-analyte sensing system is completed and successfully tested for CVD patient's plasma, it can provide rapid (<10 min) and reliable diagnostic and prognostic information at a patient's bedside.

Tang, Liang; Ren, Yongjie; Hong, Bin; Kang, Kyung A.

2006-03-01

367

A six year follow up study of the subclinical effects of carbon disulphide exposure on the cardiovascular system  

PubMed Central

Aims: A six year prospective cohort study was conducted to clarify whether the current carbon disulphide (CS2) exposure level is low enough to prevent subclinical health impairment and/or to ameliorate health effects due to previous high exposure. This paper describes the effects on the cardiovascular systems. Methods: The study subjects were 432 male workers exposed to CS2 and 402 non-exposed workers in Japan, all of whom were examined in 1992–93. A total of 251 CS2 exposed, 140 formerly exposed, and 359 non-exposed workers participated in the follow up survey (follow up rate 89.9%) in 1998–99. Mean duration of exposure was 19.3 years at the end the study. Mean CS2 and 2-thiothiazolidine-4-carboxylic acid (TTCA) concentrations were 5.0 ppm and 1.6 mg/g creatinine. Health items examined were serum biochemical indices including lipids and coagulation-fibrinolysis factors, blood pressure, aortic stiffness, ophthalmography, and electrocardiography at rest and after Master's double 2 step test. Potential confounding factors were adjusted for. Results: Incidence of ischaemic findings, defined as Minnesota codes I, IV1–3, V1–3 (at rest and after the load), or receiving treatment for ischaemia, was significantly higher in the exposed workers, especially for the spinning/refining workers (adjusted OR 2.1; 95% CI 1.1 to 4.0) or the highest quartile of six year mean TTCA (adjusted OR 3.9; 95% CI 1.8 to 8.7), although the observed increase in risk was diminished when rigorous ECG criteria were applied. Incidence of retinal microaneurysm was increased with marginal significance. Among cardiovascular risk factors we examined, only blood pressure values were significantly increased in the exposed workers. Conclusions: Increased risk of ischaemic electrocardiogram findings among Japanese viscose rayon workers was observed. Although its clinical significance is to be discussed, the current Japanese occupational exposure limit for CS2, 10 ppm, would be high to prevent subclinical cardiovascular effects in this study population.

Takebayashi, T; Nishiwaki, Y; Uemura, T; Nakashima, H; Nomiyama, T; Sakurai, H; Omae, K

2004-01-01

368

Society for Cardiovascular Magnetic Resonance guidelines for reporting cardiovascular magnetic resonance examinations  

PubMed Central

These reporting guidelines are recommended by the Society for Cardiovascular Magnetic Resonance (SCMR) to provide a framework for healthcare delivery systems to disseminate cardiac and vascular imaging findings related to the performance of cardiovascular magnetic resonance (CMR) examinations.

Hundley, W Gregory; Bluemke, David; Bogaert, Jan G; Friedrich, Matthias G; Higgins, Charles B; Lawson, Mark A; McConnell, Michael V; Raman, Subha V; van Rossum, Albert C; Flamm, Scott; Kramer, Christopher M; Nagel, Eike; Neubauer, Stefan

2009-01-01

369

The Viable System Model  

Microsoft Academic Search

\\u000a The Viable System Model (VSM) is a conceptual model which is built from the axioms, principles, and laws of viable organisation.\\u000a It is concerned with the dynamic structure that determines the adaptive connectivity of the parts of the organisation or organism;\\u000a what it is that enables it to adapt and survive in a changing environment. It can be used as

Patrick Hoverstadt

2010-01-01

370

Climate system modeling program  

SciTech Connect

The Climate System Modeling Project is a component activity of NSF's Climate Modeling, Analysis and Prediction Program, supported by the Atmospheric Sciences Program, Geosciences Directorate. Its objective is to accelerate progress toward reliable prediction of global and regional climate changes in the decades ahead. CSMP operates through workshops, support for post-docs and graduate students and other collaborative activities designed to promote interdisciplinary and strategic work in support of the overall objective (above) and specifically in three areas, (1) Causes of interdecadal variability in the climate system, (2) Interactions of regional climate forcing with global processes, and (3) Scientific needs of climate assessment.

NONE

1995-12-31

371

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

372

Modeling the earth system  

SciTech Connect

The 1990 Global Change Institute (GCI) on Earth System Modeling is the third of a series organized by the Office for Interdisciplinary Earth Studies to look in depth at particular issues critical to developing a better understanding of the earth system. The 1990 GCI on Earth System Modeling was organized around three themes: defining critical gaps in the knowledge of the earth system, developing simplified working models, and validating comprehensive system models. This book is divided into three sections that reflect these themes. Each section begins with a set of background papers offering a brief tutorial on the subject, followed by working group reports developed during the institute. These reports summarize the joint ideas and recommendations of the participants and bring to bear the interdisciplinary perspective that imbued the institute. Since the conclusion of the 1990 Global Change Institute, research programs, nationally and internationally, have moved forward to implement a number of the recommendations made at the institute, and many of the participants have maintained collegial interactions to develop research projects addressing the needs identified during the two weeks in Snowmass.

Ojima, D. [ed.

1992-12-31

373

Sleep deprivation, sleep apnea and cardiovascular diseases.  

PubMed

Sleep dramatically influences cardiovascular regulation. Changes in sleep duration or quality as seen in sleep disorders may prevent blood pressure to fall during sleep as expected in human physiology. This supports the increased prevalence of hypertension and drug-resistant hypertension in those with sleep loss. Other cardiovascular outcomes i.e. coronary lesions seem to be associated with sleep duration. Systemic inflammation, oxidative stress and endothelial dysfunction seem to be associated with both sleep loss and sleep disorders. The most critical example is Obstructive Sleep Apnea (OSA). Sympathetic activation, oxidative stress and systemic inflammation are the main intermediary mechanisms associated with sleep apnea and intermittent hypoxia. There are now convincing data regarding the associations between hypertension, arrhythmias, stroke, coronary heart disease, increased cardiovascular mortality and OSA. There are also data in OSA and in animal models supporting the link between sleep apnea and atherosclerosis and dysmetabolism. Whether treating sleep apnea enables the reversal of chronic cardiovascular and metabolic consequences of OSA, remains to be studied in adequately designed studies, particularly in comparison with usual treatment strategies. PMID:22202016

Levy, Patrick; Tamisier, Renaud; Arnaud, Claire; Monneret, Denis; Baguet, Jean Philippe; Stanke-Labesque, Francoise; Dematteis, Maurice; Godin-Ribuot, Diane; Ribuot, Christophe; Pepin, Jean-Louis

2012-01-01

374

INTEGRATED GLOBAL SYSTEM MODEL  

EPA Science Inventory

The MIT Integrated Global System Model (IGSM) is designed for simulating the global environmental changes that may arise as a result of anthropogenic causes, the uncertainties associated with the projected changes, and the effect of proposed policies on such changes. As described...

375

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

376

A model for the design and evaluation of algorithms for closed-loop cardiovascular therapy  

Microsoft Academic Search

Developing a clinically useful closed-loop drug delivery system can be extremely time consuming and costly. One approach to reducing the time and cost associated with developing closed-loop systems is to reduce the number of animal experiments and perform an extensive set of simulation studies. Through simulations, a closed-loop controller's performance can be evaluated over a complete spectrum of the patient

Eileen A. Woodruff; James F. Martin; Madonna Omens

1997-01-01

377

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