Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cardiovascular System”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources
PubMed1988

[Flow imaging of the cardiovascular system using magnetic resonance imaging].

Blood flow images by magnetic resonance imaging (MRI) using a 0.25 T unit were evaluated for nine normal volunteers and 108 subjects with a variety of cardiovascular abnormalities. Using the non-gated short-spin echo (SE) technique, blood flow in the cardiovascular systems was not imaged in the normal volunteers. Using end-systolic and end-diastolic SE techniques for the normal subjects, blood flow in the cardiac chambers was not clearly imaged. Blood flow in the ascending aorta and aotric arch often did not appear in the gated SE images of the normal subjects. However, blood flow in the descending aorta was often observed in the gated SE images. Blood flow imaging was demonstrated by both non-gated and gated SE techniques in regions where blood flow was relatively slow; for example, in the left atrium of mitral stenosis, in an aortic aneurysm, in a false lumen of an aortic dissection, and in the left ventricle having old myocardial infarction. Using the non-gated inversion recovery (IR) technique, no blood flow was imaged in the cardiovascular system except in the left atrium of one case with mitral stenosis. Using the non-gated short SE technique, there was good correlation between the thrombus formation and the presence of blood flow images in the left atria of 17 patients with mitral stenosis, and in the aneurysmal portions of the aorta or in the false lumens of aortic dissection of 18 patients. It was suggested that mural thrombi in such diseases were related to the relatively slow blood flow. Blood flow imaging easily distinguished stagnant blood flow from mural thrombi using non-gated short SE, end-systolic SE, and IR techniques. Thus, blood flow imaging using MRI should become an important means of evaluating the cardiovascular system.

Adult↗
PubMed2006

Beneficial effects of Provinols: cardiovascular system and kidney.

Red wine polyphenols have been reported to exert beneficial effects in preventing cardiovascular diseases but their molecular mechanisms of hemodynamic effects on functional cardiovascular and renal changes were studied much less. The review is focused on in vitro as well as in vivo effects of red wine extract containing polyphenolic compounds (Provinols) on cardiovascular systems and kidney in relation to the molecular and biochemical mechanisms of these compounds. This review provides the evidence that Provinols is able to produce ex vivo endothelium-dependent relaxation as a result of enhanced NO synthesis. Administration of Provinols partially prevents the development of hypertension during NO deficiency and accelerates the decrease of blood pressure in already established hypertension. The effects of Provinols include prevention and/or attenuation of myocardial fibrosis, reduction of aortic wall thickening and improvement of vascular functions. These functional and structural alterations are associated with significant augmentation of NO production, seen as the increase of NO synthase activity and eNOS protein expression. Moreover, it has been documented that Provinols decreased the oxidative stress within the cardiovascular system and kidney.

Animals↗
PubMed1999

[Cell polarity in the cardiovascular system].

The importance of cell polarity as a fundamental biological principle is increasingly recognized in the cardiovascular system. Polar cell mechanisms underlie not only the development of the heart and blood vessels, but also play a major role in the adult organism for polarized endothelial functions such as the separation of the intra- and extravascular compartment and the vectorial exchange of substances between these compartments. Endothelial cells are connected through intercellular junctions which separate the functionally and structurally distinct luminal and abluminal cell surfaces. The luminal plasma membrane is in contact with the blood and takes part in the regulation of hemostasis. The abluminal cell membrane connects the endothelial cell with the basement membrane and modulates blood flow through the release of vasoactive substances. Results from epithelial model systems have shown that the polarized cell phenotype is generated by specific protein sorting and regulated protein trafficking between the trans-Golgi network and the cell surface. The polarized distribution of cell membrane proteins is maintained by anchorage with the cytoskeleton and limitation of lateral diffusion by tight junctions. Disturbances of cell polarity may contribute to the pathogenesis of disease states, including ischemic and radiocontrast-induced acute renal failure and carcinomas. Recent results have demonstrated the importance of cholesterol for protein traffic from the trans-Golgi network to the apical cell membrane. This novel intracellular function of cholesterol could point to a connection between cell polarity and the pathogenesis of arteriosclerosis. The polarity of the endothelium also has to be taken into account when developing gene-therapeutic strategies, since therapeutic success will not only depend on the efficient expression of the desired gene product, but also on its correct cellular location or secretion into the correct extracellular compartment. These examples demonstrate the biological and potentially clinical relevance of cell polarity in the cardiovascular system.

Adult↗
PubMed2000

Bifurcation in a simple model of the cardiovascular system.

A simple nonlinear beat-to-beat model of the human cardiovascular system has been studied. The model, introduced by DeBoer et al. was a simplified linearized version. We present a modified model which allows to investigate the nonlinear dynamics of the cardiovascular system. We found that an increase in the alpha-sympathetic gain, via a Hopf bifurcation, leads to sustained oscillations both in heart rate and blood pressure variables at about 0.1 Hz (Mayer waves). Similar oscillations were observed when increasing the beta-sympathetic gain or decreasing the vagal gain. Further changes of the gains, even beyond reasonable physiological values, did not reveal another bifurcation. The dynamics observed were thus either fixed point or limit cycle. Introducing respiration into the model showed entrainment between the respiration frequency and the Mayer waves.

Blood Pressure↗
PubMedDate not supplied

Investigations of exercise adaptation of the cardiovascular system in pilots breathing an oxygen-poor gas mixture. Part I. Analysis of haemodynamic parameters.

The author studied exercise adaptation of the cardiovascular system in pilots breathing a gas mixture containing 12% of oxygen in nitrogen. During hypoxia the following findings were obtained: earlier achieving of the assumed peak value of heart rate, lower value of diastolic arterial blood pressure and peripheral vascular resistance. Hypoxia modified the exercise tolerance decreasing the maximal power and sum of the performed work. Differences in the adaptation response of the cardiovascular system depended on the fitness level of the pilots. Those with a high fitness level performed greater work at stable heart rates and had higher exercise tolerance during hypoxia. The exercise test in hypoxia related to the haemodynamic parameters increases significantly the scope of information about the efficiency of the cardiovascular system.

Adaptation, Physiological↗
PubMedDate not supplied

[The effect of insulin on the functional state of the cardiovascular system in patients with diabetes mellitus].

The influence of the hypoglycemic effect of the therapeutic doses of insulin on the functional condition of the cardiovascular system was studied under clinical conditions in 74 patients with various forms of diabetes mellitus; mechanocardiography was used for this purpose. Myocardial hyperfunction, an increase in the tone of the large arteries, disturbance of correlation between the cardiac output and the peripheral resistance accompanied diabetes mellitus. A moderate reduction of glycemia after insulin administration (not over 50 mg%) promoted an improvement of the cardiovascular system function, facilitated the cardiac and the extracardiac conditions of the myocardial function. A marked fall of the blood level, particularly by over 100 mg%, produced an unfavourable effect on the cardiovascular system, and aggravated the hemodynamic shifts. The optimal admissible variations in glycemia during the treatment of a diabetic patients with insulin of short action is +/-50 mg%. A gradual reduction or normalization of the blood sugar level in diabetes mellitus served as one of the important factors of prophylaxis and progress of cardiovascular disturbances in diabetes mellitus.

Adolescent↗
PubMed1982

[Importance of a comprehensive instrumental assessment of cardiovascular system function for the expert medical work evaluation of ischemic heart disease patients].

A total of 103 patients with ischaemic heart disease (IHD) were investigated 1 1/2 to 10 years after myocardial infarction. The functional state of the cardiovascular system was studied with the aid of electrocardiography, tetrapolar chest rheography and spiroergometry in the bicycle ergometric test. This test revealed ischaemic shifts on the ECG in 63% of patients with IHD. Patients with IHD, as compared to the control group of normal individuals, showed lowered tolerance to exercise and shifts in the indices of the central haemodynamics and gaseous exchange, including less manifest increase of the stroke and minute volume of blood, and oxygen consumption. The results of the study permitted the authors to diagnose the initial state of the cardiac insufficiency and to graduate the functional possibilities of the cardiovascular system in patients with IHD. It is recommended to use such a comprehensive cardiological study of the functional state of the cardiovascular system for medical assessment of the working capacity of IHD patients.

Adult↗
PubMed2001

Modelling couplings among the oscillators of the cardiovascular system.

A mathematical model of the cardiovascular system is simulated numerically. The basic unit in the model is an oscillator that possesses a structural stability and robustness motivated by physiological understanding and by the analysis of measured time series. Oscillators with linear couplings are found to reproduce the main characteristic features of the experimentally obtained spectra. To explain the variability of cardiac and respiratory frequencies, however, it is essential to take into account the rest of the system, i.e. to consider the effect of noise. It is found that the addition of noise also results in epochs of synchronization, as observed experimentally. Preliminary analysis suggests that there is a mixture of linear and parametric couplings, but that the linear coupling seems to dominate.

Artifacts↗
PubMed1987

[Bladder instillation of verapamil as a means of enhancing the efficacy of chemotherapy in superficial bladder carcinoma: influence of bladder instillation of verapamil on the cardiovascular system].

Although it is well known that calcium antagonists in vitro possess enhancing effects on anti-tumor drugs, their clinical use is limited on account of side effects on the cardiovascular system. In the present study, the authors attempted the instillation of Verapamil (calcium antagonist) combined with anti-tumor drugs into the bladder for the treatment of superficial bladder carcinoma. The dosage of Verapamil necessary for maintaining an effective concentration for enhancement of the anti-tumor drug was determined and the influences of bladder instillation of Verapamil on the cardiovascular system and on the bladder were studied. The results obtained were as follows: the use of 5 mg of Verapamil was able to maintain an effective concentration (10(-5) M) for enhancement of anti-tumor drugs for at least 2 h. Absorption of Verapamil from the bladder to the vascular system was minimal. No influence on the cardiovascular system or on the bladder was observed. The results of the present study encourage us to pursue the clinical use of Verapamil combined with anti-tumor drugs for the treatment of superficial bladder carcinoma.

Administration, Intravesical↗
PubMed2002

[Regulation of the human cardiovascular system under microgravitation].

The paper presents the results of studies of the cardiovascular system and analyzes the mechanisms of regulation and adaptation of this system during long-term space flights. Special attention is given to the analysis of the homeostatic mechanisms for maintaining a number of integrative parameters of the cardiovascular system at the pre- and near-flight level and to the mechanisms of development of orthostatic detraining character after flights. How a new level of circulatory function in the absence of microgravitation is formed is shown.

Adaptation, Physiological↗
PubMed1999

Molecular control of nitric oxide synthases in the cardiovascular system.

Nitric oxide plays an important role in cardiovascular homeostasis. In this review, the regulation of the three nitric oxide synthase isoforms in the cardiovascular system are examined at molecular and cellular levels. In addition, recent information gleaned from the use of NOS knockout mice are discussed.

Animals↗
PubMed1997

Alcohol and the cardiovascular system: molecular mechanisms for beneficial and harmful action.

Alcohol can be beneficial or harmful to the cardiovascular system, depending on the amount consumed and the characteristics of the consumer. Of the numerous cellular and molecular mechanisms that are thought to explain the beneficial effects of moderate drinking, this article discusses four, involving (1) high density lipoproteins, (2) cellular signaling, (3) platelet function in blood clot formation, and (4) stimulation of blood clot dissolution. Although light-to-moderate drinking can protect against coronary artery disease, heavy alcohol consumption can damage the cardiovascular system, resulting in maladies such as heart muscle disorders, irregular heart rhythms, high blood pressure, and strokes. This article summarizes representative epidemiological and animal studies on these cardiovascular consequences of chronic heavy alcohol consumption and reviews mechanisms that have been suggested to explain alcohol's effects.

Alcohol Drinking↗
PubMed1993

Involvement of the area postrema in the regulation of sympathetic outflow to the cardiovascular system.

The circumventricular organs of the brain have been implicated in the central regulation of the cardiovascular system. The area postrema, which is the only circumventricular organ in the hindbrain, has received less attention than the others, but recent studies suggest that it may play an important role in the regulation of the cardiovascular system. Studies in rats and rabbits indicate that angiotensin II (Ang II)-dependent hypertension is abolished by lesioning of the area postrema. Additional studies indicate that the hypertension associated with Ang II involves a resetting of the arterial baroreflex to a higher pressure. This upward resetting requires an interaction of neurons in the area postrema with barosensitive neurons terminating in the medial nucleus tractus solitarius (mNTS). Another peptide, arginine vasopressin (AVP), has been shown to enhance the sympathoinhibitory influence of the arterial baroreflex via an action at the area postrema. Studies in rabbits suggest that the sympathoinhibitory response is due to resetting of the baroreflex to a lower pressure. Electrophysiological studies, using an in vitro brain slice preparation, have shown that activation of area postrema neurons projecting to the mNTS alters the responsiveness of mNTS neurons to afferent inputs. It is postulated that alpha-adrenergic mechanisms are involved in these interactions.

Animals↗
PubMed1984

Central activation and peripheral function of sympatho-adrenal and cardiovascular systems in the Zucker rat.

Electrical stimulation of the hypothalamus in anesthetized lean and obese Zucker rats produced equivalent activation of the sympatho-adrenal system (assessed by plasma norepinephrine [NE] and epinephrine [E] levels) and cardiovascular systems (assessed by monitoring intra-arterial blood pressure and heart rate). Basal plasma E levels were 11% higher and basal heart rates were 20% higher in obese than lean rats. Binding of beta-adrenergic antagonist, [3H] dihydroalprenolol to cardiac membranes was equal but there was a slightly lower affinity for various adrenergic agonists in the hearts of obese compared to lean rats. These results suggest that there are no striking abnormalities in the central pathways for activation of the sympatho-adrenal and cardiovascular systems of obese Zucker rats comparable to those previously described in the peripheral sympatho-adrenal system and other specific organs of these animals [8, 9, 12-15].

Adrenal Glands↗
PubMedDate not supplied

Modulatory effect of acupuncture on the cardiovascular system: a cross-over study.

The effect of acupuncture on the cardiovascular system was studied in 23 healthy males in a cross-over design comparing acupuncture and a placebo pill by measuring skin blood flow and the function of the heart. Acupuncture was found to have a modulatory effect on skin blood flow (correlation coefficient (r) = -0.68; p < 0.0005) and heart rate (r = -0.56; p < 0.005), as well as Blood-Pressure-Heart-Rate-Product (r = -0.70; p < 0.0002). The combination of rest and a placebo pill had no modulatory effect on skin blood flow, but did have a delayed effect on the heart when compared with acupuncture. The results indicate that acupuncture has the ability to enhance the regulatory mechanisms of the cardiovascular system. The possible underlying mechanism is discussed. The findings represent a physiological explanation for the possible utility of acupuncture in maintaining cardiovascular homeostasis in healthy people.

Acupuncture Therapy↗
PubMed1982

Interaction of ouabain and propranolol in the central nervous system. Neurally-mediated effects on the cardiovascular system.

The effect of intracerebroventricular (i.c.v.) ouabain alone and after pretreatment with i.c.v. (+/-)-propranolol, (+)-propranolol, UM-272 (a quaternary analogue of propranolol) and lignocaine, on arterial blood pressure (BP), heart rate (HR) and cardiac rhythm was investigated in chloralose anesthetized, vagotomized cats. Ouabain elicited an increase in BP and HR followed by cardiac arrhythmias of ventricular origin. Pretreatment with (+/-)-propranolol, (+)-propranolol or UM-272 attenuated/prevented the cardiovascular effects of ouabain whereas lignocaine did not modify the response appreciably. Since UM-272, which lacks local anesthetic activity and beta-blocking activity also shared the antagonism with (+/-)-and (+)-propranolol, it is deduced that neither beta-blocking nor local anesthetic activity of propranolol could be responsible for this antagonism. This is supported by the fact that lignocaine which has a comparable local anesthetic effect of propranolol failed to modify significantly the cardiovascular response to ouabain. The antagonism appears to be a direct neural depressant effect independent of local anesthetic action. The neural depressant effect may be due to an interference in depolarization process and/or a neurone-blocking effect.

Animals↗
PubMedDate not supplied

[Effect of physical exertion on the adrenal gland function and cardiovascular system in diabetes mellitus].

The response of the adrenal glands and the cardiovascular system to dosaged cycloergometric exercises was studied in 35 young patients with diabetes, depending on the state of carbohydrate metabolism, in comparison with control healthy individuals. In diabetic patients physical load proved to induce an insignificant activation of the adrenal glucocorticoid function with a marked response of the sympathicoadrenal system. Physical exercises permitted to detect reduction of myocardial reserves and disturbance of vascular reactivity in the majority of diabetic patients. The detected changes in the adrenal gland response could serve as one of the causes of inadequate response of the cardiovascular system to physical load, and of reduced tolerance to it in diabetic patients.

17-Hydroxycorticosteroids↗