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At least 433 records · Page 24Linked to original sources
PubMed1976

The effects of the fenoterol hydrobromide (Partusisten) aerosol on uterine activity and the cardiovascular system.

Fenoterol hydrobromide (Partusisten) aerosol was used in a placebo-controlled, double-blind, double crossover trial to study its effects on oxytocin-induced uterine contractions and the maternal cardiovascular system. The active and placebo aerosols were each administered a total of ten times or twice each in five patients who were in established oxytocin-induced labour with intact membranes. Five puffs, of 200 mug each, of the active aerosol reduced uterine activity by more than half; the effect on the cardiovascular system was to cause a mild tachycardia and to widen the pulse pressure.

Aerosols↗
PubMed2005

KATP channel: relation with cell metabolism and role in the cardiovascular system.

ATP-sensitive potassium channel (K(ATP)) is one kind of inwardly rectifying channel composed of two kinds of subunits: the pore forming subunits and the regulatory subunits. K(ATP) channels exist in the sarcolemmal, mitochondrial and nuclear membranes of various tissues. Cell metabolism regulates K(ATP) gene expression and metabolism products regulate the channel by direct interactions, while K(ATP) controls membrane potentials and regulate cell activities including energy metabolism, apoptosis and gene expression. K(ATP) channels from different cell organelles are linked by some signal molecules and they can respond to common stimulation in a coordinate way. In the cardiovascular system K(ATP) has important functions. The most prominent is that opening of this channel can protect cardiac myocytes against ischemic injuries. The sarcolemmal K(ATP) may provide a basic protection against ischemia by energy sparing, while both the sarcolemmal K(ATP) and mitochondrial K(ATP) channels are necessary for the ischemia preconditioning. K(ATP) channels also have important functions including homeostasis maintenance and vascular tone regulation under physiological conditions. Further elucidation of the role of K(ATP) in the cardiovascular system will help us to regulate cell metabolism or prevent damage caused by abnormal channel functions.

Cardiovascular System↗
PubMed2004

Urocortins and corticotropin releasing factor type 2 receptors in the hypothalamus and the cardiovascular system.

In addition to urocortin (Ucn I), Ucn II and Ucn III were identified as endogenous ligands for corticotropin-releasing factor type 2 receptor (CRF2 receptor). CRF2 receptor is abundantly located in central hypothalamic ventromedial nucleus (VMH) and in peripheral cardiovascular system. In this mini-review, we focused on the roles of these urocortins and CRF2 receptor in the hypothalamus and the cardiovascular system. Ucn II mRNA was increased in the parvocellular part or the magnocellular part of the hypothalamic paraventricular nucleus (PVN) following immobilization stress or 3 days of water deprivation, respectively. Therefore, it is thought that Ucn II may modulate CRF and vasopressin synthesis in the PVN in a paracrine or autocrine fashion through PVN CRF2 receptor. The early and later phases of Ucn I-mediated feeding suppression may be CRF1 and CRF2 receptor-mediated events, respectively. Ucn II decreases food intake at a later phase, beyond 4 h post injection. A large dose of corticosterone increased plasma leptin and insulin levels as well as the levels of CRF2 receptor mRNA. Adrenalectomy, starvation, and immobilization each lowered plasma leptin and insulin levels and were associated with decrements in CRF2 receptor mRNA levels in the VMH. Peripheral injection of leptin increased VMH CRF2 receptor mRNA, as can induce reductions of food intake and body weight, indicating that circulating leptin is involved in the regulation of VMH CRF2 receptor mRNA expression. Therefore, it is also plausible that VMH CRF2 receptor transduces the anorexogenic effects of leptin as well as those of urocortins. The systemic administration of Ucn II decreases mean arterial pressure (arterial vascular tone) and causes tachycardia via vascular CRF2 receptor in rats, similar to the effects of Ucn I. Thus, CRF2 receptor seems to mediate cardioprotective effects of urocortins.

Animals↗
PubMed2006

Role of the ephrin and Eph receptor tyrosine kinase families in angiogenesis and development of the cardiovascular system.

Angiogenesis is a highly complex orchestrated process that plays a critical role in normal development and in the pathophysiology of multiple disease processes, including tumour neovascularization, ischaemic recovery, and wound healing. In recent years there has been a resurgence of interest in Eph receptors and their ligands, ephrins, as their participation in vasculogenesis and angiogenesis has become apparent. The Eph receptor family is the largest family of receptor tyrosine kinases identified to date. The Eph receptors and their membrane-anchored ligands, ephrins, are unique in that they mediate bi-directional signalling. This is concomitant with activation of the Eph receptor tyrosine kinase domain and transduction of the typical forward signal into the receptor-bearing cell. The ligand-receptor interaction also leads to transduction of a reverse signal into the ephrin-bearing cell. The Eph/ephrin signalling mechanism is responsible for diverse and complex biological functions mediated by Eph receptors and ephrin ligands. These include vascular development, tissue-border formation, cell migration, axon guidance, and synaptic plasticity. The role of Eph receptors and ephrins in the processes of development of the cardiovascular system, angiogenesis, and vascular remodelling has been the subject of intense investigation since they were first identified in 1987. This review addresses the role of this new growth factor receptor tyrosine kinase family in those processes and provides new insights into the way in which Eph receptors and ephrin ligands modulate the angiogenic response and participate in vascular remodelling and vascular boundary formation during development of the cardiovascular system and vascularization of cancer.

Animals↗
PubMed1988

CADCS simulation of the closed-loop cardiovascular system.

A pulsatile simulator of the closed-loop cardiovascular system, designed to solve simulation, identification and control problems in a research and education context, is presented. Its implementation makes use of a command-driven interactive program for simulation of non-linear ordinary differential equations. The flexibility of the simulator is demonstrated by the results presented which refer to a basal steady-state circulatory condition as well as a transient induced by an abrupt change in peripheral resistance.

Blood Pressure↗
PubMed1983

Pharmacological effects of pyrethroids on the cardiovascular system of the rat.

The cardiovascular actions of two pyrethroids, deltamethrin and cismethrin, were assessed using the pithed rat, the isolated working heart, and perfused mesentery preparations. Deltamethrin but not cismethrin, increased mean arterial pressure and differential pressure in the pithed rat, and the aortic output and mean systolic aortic pressure in the working heart. Reserpine pretreatment reduced, but did not abolish, the pressor response to deltamethrin in the pithed rat and working heart, but did not reduce the increase in aortic output following deltamethrin in the working heart. In the perfused mesentery, deltamethrin did not modify the action of exogenous noradrenaline, but increased the response to 10 Hz stimulation. It is concluded that the cardiovascular effects of deltamethrin are due to both increased catecholamine release in peripheral vascular beds, and to a direct positive inotropic effect on the heart. The results also provide a distinction between the action of the two pyrethroids in terms of their cardiovascular activity.

Animals↗
PubMed1999

[Application of power band graph method to the modeling and simulation of cardiovascular system].

This paper presents a computer simulation model of the cardiovascular circulation system, which describes the blood flow dynamic law in the cardiovascular system by the state equation. The model can be used in physiological study and computer-aided medical education. In this paper, the Power Band Graph (PBG) modeling method is used to realize modeling of the human circulation system and conduct a simulation study on a simplified physiological system model. The results demonstrate that the PBG method, as an understandable and unity modeling method, is quite effective and practicable and can be used widely in the field of physiological system simulation.

Computer Simulation↗
PubMed1988

Magnetic resonance imaging of the cardiovascular system. Present state of the art and future potential. Council on Scientific Affairs. Report of the Magnetic Resonance Imaging Panel.

State-of-the-art magnetic resonance imaging (MRI) generates high-resolution images of the cardiovascular system. Conventional MRI techniques provide images in six to ten minutes per tomographic slice. New strategies have substantially improved the speed of imaging. The technology is relatively expensive, and its cost-effectiveness remains to be defined in relation to other effective, less expensive, and noninvasive technologies, such as echocardiography and nuclear medicine. The ultimate role of MRI will depend on several factors, including the development of specific applications such as (1) noninvasive angiography, especially of the coronary arteries; (2) noninvasive, high-resolution assessment of regional myocardial blood flow distribution (eg, using paramagnetic contrast agents); (3) characterization of myocardial diseases using proton-relaxation property changes; and (4) evaluation of in vivo myocardial biochemistry. The three-dimensional imaging capability and the ability to image cardiovascular structures without contrast material give MRI a potential advantage over existing noninvasive diagnostic imaging techniques. This report analyzes current applications of MRI to the cardiovascular system and speculates on their future.

Angina Pectoris↗
PubMed1988

The hemodynamics of the aging cardiovascular system.

Our information on the hemodynamics of the aging cardiovascular system in normotensive and hypertensive subjects is mainly based on cross-sectional studies. In normotensive subjects with no indication of coronary heart disease, recent noninvasive studies seem to indicate that cardiac output at rest and during exercise does not decline with age. These results contrast with what has been found by invasive studies in unselected populations. In hypertensive subjects it is well established that the hemodynamics of young subjects at the early stage differ greatly from what is seen in elderly hypertensive subjects. In the early phase, a high resting cardiac output is typical, whereas in the elderly, cardiac output is very low and total peripheral resistance (TPR) very high. Echo studies have shown that left ventricular hypertrophy develops early in hypertension--together with increased stiffness and reduced left ventricular compliance. A subnormal stroke volume during exercise is seen early in the process of hypertension. Data from the 20-year follow-up study of the Bergen population demonstrate that in groups of young (17-29 years) versus elderly (60-69 years) patients with hypertension with the same mean arterial blood pressure, the hemodynamic mechanisms behind increased blood pressure were widely different. The increase in mean arterial blood pressure during exercise was much steeper in the older subjects than in the younger ones, and TPR was about twice as high during 150 W exercise. Cardiac index (CI) in the oldest group was approximately half of that in the youngest group. The differing hemodynamic patterns in the young and elderly might have implications for when and how to start drug treatment, and also for what type of treatment to select.

Adult↗
PubMed1983

Nuclear magnetic resonance imaging of the cardiovascular system: normal and pathologic findings.

Whole body nuclear magnetic resonance (NMR) imaging of the cardiovascular system was carried out in early clinical trials in 244 volunteers and patients using a 3.5 KGauss (0.35 T) unit. The spin echo technique with multiple imaging parameters was used. Blood vessels were clearly discriminated from solid organs and lesions because little or no intraluminal signal is seen with laminar blood flow at normal velocities, whereas a more intense image is generated by solid organs. Characteristic flow signals were observed in normal patients and were accentuated by varying the imaging parameters. Cardiac chambers were well delineated in some patients on nongated images. In one case, internal topography of the ventricles was exquisitely displayed on a gated image. Intraluminal pathology, such as dissection of the aorta, aneurysms of the aorta and left ventricle, and aortic atheroma, was clearly demonstrated. Patency of coronary arterial bypass grafts was shown. Abnormal flow patterns due to slow or turbulent flow were accentuated on images using the second spin echo. This preliminary experience indicates the considerable potential of NMR imaging in the evaluation of cardiovascular diseases.

Blood Flow Velocity↗
PubMed2002

[The cardiovascular system of patients with lymphogranulomatosis in long-time remission].

AIM: To study the cardiovascular system in patients with lymphogranulomatosis (LGM) at prolonged remission. MATERIALS AND MATERIALS: 78 patients received radiation and chemotherapy for lymphogranulomatosis in 1973 to 1995. All the patients underwent electro- and echocardiography (EchoCG), 40 patients had radioisotopic ventriculography (RVG). RESULTS: EchoCG revealed nonspecific changes in the ST segment in 19 (24.3%) patients. Systolic function was decreased vto 46% only in 1 patient. RVG showed a significant reduction in ejection fraction in the experimental group as compared to the control one (55.5 +/- 9.5 and 68.4 +/- 8.0, respectively; p < 0.05). CONCLUSION: Cardiac disorders revealed in patients with LGM at prolonged remission are mainly insignificant. The risk for cardiac events is not a guide for reducing radiation doses and the intensity of chemotherapy.

Adult↗
PubMed1995

Structural changes in the cardiovascular system of untreated essential hypertensives.

Arterial hypertension is associated with structural changes in the cardiovascular system. This study has examined the effect of hypertension on the carotid artery wall and examined the relation between changes in the structure of carotid artery wall and left ventricle in untreated hypertensives. The carotid artery wall was visualized using a high resolution ultrasound technique in 37 untreated hypertensive patients (25 males, 12 females) and 37 age and sex matched normotensive individuals and carotid intima-media thickness (IMT) and carotid artery diameter measured. IMT and intima-media cross sectional area was significantly greater in the hypertensive group compared with the normotensive group, though the carotid artery diameter did not differ significantly. There was a significant association between age and IMT in both groups. In the hypertensive group there was also a significant association between left ventricular mass index, ventricular septal or posterior wall thickness and IMT. This study indicates that there is an association between cardiac and carotid arterial structure in hypertension. Such a relationship may be important in understanding the associated risks of high blood pressure.

Adult↗
PubMed1997

Can twin fetuses be numerically clustered characterizing fetal cardiovascular system function?

To clarify whether twin fetuses could be clustered quantitatively observing in utero cardiovascular system function, 71 twin-paired fetuses between 24 and 40 weeks' gestation were subjected. Cluster analysis was performed using four variables; end-diastolic dimension and fractional shortening in the right ventricle (EDD, FS), resistance index in the umbilical artery (RIUA) and urine production rate (UPR). Three different groups were revealed. In Cluster 1 (C1), larger fetuses showed a significant increase in both EDD and UPR, and a significant decrease in FS, while smaller fetuses had a significant increase in RIUA and a decrease in UPR. In Cluster 2 (C2), smaller fetuses showed a significant increase in RIUA. Cluster 3 (C3) showed no significant deviations in any variable when referring to singleton pregnancies. C1 had a higher perinatal mortality rate than either C2 or C3, with the cause of death being cardiac failure in larger fetuses and renal failure in smaller fetuses. The frequencies of discordancy, hemoglobin difference above 5 g/dl and monochorionic placenta in C1 were also higher than fetuses in C3. C2 also showed higher frequencies of discordancy and small-for-gestational age than C3 fetuses. In C2 and C3, respiratory insufficiency was found to be the cause of neonatal death. The results revealed that C1 consists of twins with both larger and smaller fetuses displaying cardiac failure with an increase in renal perfusion and a decrease in renal and placental perfusion, respectively, and C2 consists of twins with smaller fetuses having both placental insufficiency and intrauterine growth retardation. C3 consists of twins with both lager and smaller fetuses having normal circulation, when compared to singleton pregnancy.

Birth Weight↗
PubMedDate not supplied

[Behavior of the cardiovascular system in outer space].

One of the important factors in outer space is the absence of gravity (OG). During longterm missions, this factor is responsible for the larger number of anatomical and physiological changes that astronauts experience. The cardiovascular system undergoes these changes with severe intensity, which is part of an adaptation process to the new environmental conditions. The modifications observed in both the anatomy of the cardiovascular system and its hemodynamics occur in two phases. The first phase begins when the astronauts enter into Earth orbit or in interplanetary trajectory and extends until the second or fourth day of the mission. It is characterized by an important shifting of fluids from the lower extremities to the cephalic regions which produces an increase of the venous return and the preload, the heart rate is increased, the blood volume in the thorax is also increased, the cardiac chambers become dilated, and by reflex action, the antidiuretic hormone diminishes, diuresis increases and leads to a virtual state of dehydration. Clinically, the first stage is manifested by headache, dizziness, space disorientation, nausea, anorexia, projectile vomiting, sweating and pallor. This constalation of data is known as "The Space Adaptation Syndrome". The second phase begins at the end of the first phase and finishes toward the fortieth or fiftieth day of the mission.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular Physiological Phenomena↗
PubMed2006

Simulation of hemodynamic responses to the valsalva maneuver: an integrative computational model of the cardiovascular system and the autonomic nervous system.

The Valsalva maneuver is a frequently used physiological test in evaluating the cardiovascular autonomic functions in human. Although a large pool of experimental data has provided substantial insights into different aspects of the mechanisms underlying the cardiovascular regulations during the Valsalva maneuver, so far a complete comprehension of these mechanisms and the interactions among them is unavailable. In the present study, a computational model of the cardiovascular system (CVS) and its interaction with the autonomic nervous system (ANS) was developed for the purpose of quantifying the individual roles of the CVS and the ANS in the hemodynamic regulations during the Valsalva maneuver. A detailed computational compartmental parameter model of the global CVS, a system of mathematical equations representing the autonomic nervous reflex regulatory functions, and an empirical cerebral autoregulation (CA) model formed the main body of the present model. Based on simulations of the Valsalva maneuvers at several typical postures, it was demonstrated that hemodynamic responses to the maneuver were not only determined by the ANS-mediated cardiovascular regulations, but also significantly affected by the postural-change-induced hemodynamic alterations preceding the maneuver. Moreover, the large-magnitude overshoot in cerebral perfusion immediately after the Valsalva maneuver was found to result from a combined effect of the circulatory autonomic functions, the CA, and the cerebral venous blood pressure.

Afferent Pathways↗