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PubMedDate not supplied

[Study of the variations in cardiovascular system indicators using the main component method].

The main component method was used to analyze measurements of cardiovascular parameters taken in 14 healthy operators at rest. The entire sample included 237 observations. Each observation was characterized by the deviation of heart rate, mean blood pressure and stroke volume from individual data points. The latter were individual mean values of the above parameters recorded during the Valsalva maneuver. The first two main components were responsible for over 77% of total variance of signs. Visual analysis of observation distribution with respect to the components revealed small group and single data points situated peripherally at a distance from the major constellation of data points. With respect to the values in these groups it can be assumed that some of them correspond to the stressed state of the cardiovascular system. Two thirds of data points in the stressed groups are associated with the subjects who show a weak reaction to the Valsalva maneuver and one third corresponds to the true stressed state. Taking into account the Valsalva maneuver, the deviations from individual data points can be used to identify the stressed state of the cardiovascular system in healthy men at rest.

Blood Pressure↗
PubMed1985

Bulbospinal substance P and sympathetic regulation of the cardiovascular system: a review.

The neurotransmitter role of substance P in mediating sympathoexcitatory effects in the spinal cord and cardiovascular effects elicited from the ventral medulla is presented. SP neurons located in the ventral medulla project to the intermediolateral cell column (IML) of the thoracic spinal cord. Intrathecal administration of a SP analog excites sympathetic outflow to the cardiovascular system. Likewise, activation of the ventral medulla results in sympathetically mediated increases in blood pressure and heart rate which are blocked with SP antagonists. The IML contained a high density of SP binding sites through which the peptide likely exerts its sympathoexcitatory influence on the cardiovascular system.

Animals↗
PubMed2003

The myth of ventrally emigrating neural tube (VENT) cells and their contribution to the developing cardiovascular system.

The cardiac neural crest cells are a group of cells that emigrate from the dorsal side of the neural tube during a specific time window and contribute to the pharyngeal arch arteries and the aorticopulmonary septum of the heart. Recent publications have suggested that another group of cells emigrating from the ventral side of the neural tube also contributes to the developing cardiovascular system. The first aim of our study was to define the specific time window of cardiac neural crest cell migration by injecting a retrovirus containing a lacZ reporter gene into a chick embryo at different stages during development. The second aim was to study the contribution of the supposed ventrally emigrating neural tube cells to the cardiovascular system using three approaches. One approach was to inject a lacZ retrovirus into the lumen of the chick hindbrain. Secondly, we injected the retrovirus into the neural tube at the position of the 10-12 somite pair. Finally, we used the chimera technique in which we transplanted a quail neural tube segment into a chick embryo. Cardiac neural crest cells were shown to emigrate from the dorsal side of the neural tube between HH9 and HH13(-). The HH13(+) neural tube has ceased to produce cardiac neural crest cells between the level of the otic placode and the fourth pair of somites. Retroviral injection directly into the chick hindbrain at HH14 resulted in 50% of the embryos with minimal labeling of the hindbrain and intense labeling of the adjacent mesenchyme, suggesting that virus was spilled. This implies that this technique is not useful for confirming the existence of ventrally emigrating cells. Both retroviral injections into the neural tube lumen at HH14 at the position of the 10-12 somite pair and the chimeras showed no signs of ventrally emigrating neural tube cells. We conclude that there is no contribution of ventral neural tube cells to the developing cardiovascular system.

Animals↗
PubMed2005

Effects of atrial contraction, atrioventricular interaction and heart valve dynamics on human cardiovascular system response.

Various simulation models of different complexity have been proposed to model the dynamic response of the human cardiovascular system. In a related paper we proposed an improved numerical model to study the dynamic response of the cardiovascular system, and the pressures, volumes and flow-rates in the four chambers of the heart, which included the effects of atrial contraction, atrioventricular interaction, and heart valve dynamics. This paper investigates the effects of each one of these aspects of the model on the overall dynamic system response. The dynamic response is studied under different situations, with and without including the effect of various features of the model, and these situations are studied and compared among themselves and to detailed aspects of expected healthy-system response. As an important contribution with potential clinical applications, this paper examines the corresponding effects of atrioventricular interaction, and heart valve opening and closing dynamics to the general system dynamic response. This isolation of physical cause-effect relationships is difficult to study with purely experimental methods. The simulation results agree well with results in the open literature. Comparison shows that introduction of these new features greatly improves the simulation accuracy of the effects of a, v and c waves, and in predicting regurgitant valve flow, the dichrotic notch, and E/A velocity ratio.

Animals↗
PubMed1987

The effects of metabolic diseases on the cardiovascular system.

Many metabolic diseases result in pathological changes within the cardiovascular system, often with the most severe effects on the function of the heart and great vessels. Metabolic disorders affecting the heart include disorders of amino acid metabolism, storage diseases, neuromuscular diseases, diseases of metal and pigment metabolism, carnitine deficiency, and connective tissue disorders. Several inborn errors of metabolism may involve the myocardium due to the accumulation of abnormal metabolites in the myocardial cells. In addition, the heart valves and coronary vessels may be involved. If the predominant effect is in the myocardial cell, it will be manifested clinically as a cardiomyopathy. Some disorders, in particular oxalosis, may involve the conduction system as a result of the deposition of oxalate crystals and result in conduction disturbances such as in alkaptonuria, primary oxalosis, and homocystinuria. Myocardial involvement may result in cardiomyopathy of the three functional types: (1) congestive, as in Fabry's disease, (2) hypertrophic, as in glycogen storage disease, type II, or (3) restrictive, as in Gaucher's disease. In the storage disease severe valvular as well as myocardial involvement occur predominantly in the glycogen storage diseases, types II-IV, mucolipidoses, sphingolipidoses, and neuronal ceroid lipofuscinosis. There are a variety of neuromuscular disorders that may be associated with cardiomyopathy, including the muscular dystrophies, Friedreich's ataxia, and Kugelberg-Welander syndrome. The pathological features of these conditions are not specific, but result usually in a congestive form of cardiomyopathy. Patients with metal and pigment metabolic disorders include iron storage disease, either hemochromatosis or transfusional hemosiderosis, Menkes' kinky hair syndrome, and Dubin-Johnson syndrome. Either a restrictive or a congestive form of cardiomyopathy may occur. The systemic form of carnitine deficiency is an autosomal recessive disorder and may present as a cardiomyopathy with congestive heart failure and lipid accumulation in the myocardial cells. Connective tissue disorders are generalized diseases that may involve the heart and valvular tissue, but also the blood vessels. These include Marfan's syndrome, Ehlers-Danlos syndrome, osteogenesis imperfecta, and pseudo-xanthoma elasticum.

Amino Acid Metabolism, Inborn Errors↗
PubMed1996

New non-ionic contrast: effects on the cardiovascular system.

Contrast media cause a variety of effects on the cardiovascular system both hemodynamic and electrophysiologic in nature. These effects are mainly related to the physico-chemical characteristics of the compounds and are less pronounced with low osmolar nonionic than with ionic contrast media. Nonetheless there is still room for further improvement in the features of the nonionic agents. Iomeprol is a new nonionic contrast medium which, with its low osmolality and toxicity and very low viscosity, proved to be safe and well tolerated during clinical trials in cardioangiography.

Angiocardiography↗
PubMed1994

Cardiovascular systemic invasion by hepatocellular carcinoma: incidence and pattern in a west African population.

To determine the frequency of cardiovascular systemic invasion by hepatocellular carcinoma (HCC). Eighty-one Nigerian patients who had autopsy examinations were studied. Of these, 36 (44%) had tumour thrombi within the cardiovascular system (CVS) or metastases to the heart itself. Compared with the patients without CVS invasion, no clinicopathologic findings distinguished these two groups from each other. Furthermore, CVS invasion did not worsen the generally bad prognosis of these patients with liver cancer. It is concluded that CVS invasion is frequent and difficult to diagnose by clinical examination. Patients who are selected to undergo hepatic resection must be assessed by imaging techniques to exclude CVS invasion. However, it is unlikely that frequent and routine imaging procedures will affect the generally bad prognosis of the majority of the patients.

Adolescent↗
PubMed1978

Assessment of the cardiovascular system in conjoined thoracopagus twins.

The thoracoomphalopagus conjoined twins comprise 75% of all conjoined twins. In the assessment of the organ systems of the twins, the cardiovascular system is important since union of this system in the twins has occurred in 75% of the cases. Of the five cases reported here, two had separate hearts and vessels with a common pericardium only. Two twins were joined at the right atrial level. The fifth pair were connected at both atrial and ventricular levels. It has been suggested that the presence of two separate QRS complexes in the ECG indicates complete separation of the two hearts. Case 4 shows that even in the presence of atrial union, the existence of an atrioventricular block in one twin may produce a very slow heart rate, while the other twin may have a normal rate that will not influence the ventricular rate of the other. In our experience, angiocardiography has been the most useful diagnostic procedure.

Angiocardiography↗
PubMed2005

[Thyroid hormone and the cardiovascular system].

Thyroid hormone has many effects on the heart and vascular system. In hyperthyroidism changes in cardiovascular hemodynamics explain many of the clinical manifestations induced by thyroid hormones. In hypothyroidism the cardiovascular effects are opposite to those observed in hyperthyroidism, although the clinical manifestations are less obvious. This review will focus on the cardiovascular system in hyperthyroidism and hypothyroidism. In particular the subclinical dysfunctions of the thyroid gland, which occurs especially in older age, will be discussed. The clinical relevance and the necessity of diagnostic and therapy in subclinical thyroid disease are not clarified yet. In the United States an expert group has published a scientific review and guideline for the diagnosis and management of subclinical thyroid disease in 2004, which will also be outlined.

Electrocardiography↗
PubMed1979

Effects of 2-nicotinamidoethyl nitrate on the cardiovascular system.

Using the dog as experimental animal, effects on the cardiovascular system of a new vasodilator, 2-nicotinamidoethyl nitrate (SG-75), were studied. In the heart-lung preparation, the compound produced a dose-dependent increase in the coronary blood flow, which was associated with only a minimal increase in the myocardial oxygen consumption. There was essentially no change in the myocardial function. The myocardial redox potential was shifted to more positive values. In the isolated perfused heart preparation (Langendorff's preparation), SG-75 produced a dilatation of only the small resistive arterioles. However, it produced a dilatation of the large conductive artery in underperfused myocardium. SG-75 produced a significant increase in the cerebral venous outflow, associated with an increase in the cerebro-spinal fluid pressure. It produced a reducation of the venous return, which was especially prominent in the lower half of the body. In the isolated smooth muscle preparation of the coronary artery, high-doses of SG-75 induced calcium antagonistic effects and produced a relaxation of the lanthanum contracture.

Animals↗
PubMed1991

Increased proteoglycan synthesis by the cardiovascular system of coarctation hypertensive rats.

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.

Animals↗
PubMed1998

Oxidant-mediated activation of mitogen-activated protein kinases and nuclear transcription factors in the cardiovascular system: a brief overview.

In response to oxidant stress, the cardiovascular system is known to express a number of genes, which could occur owing to the participation of mitogen-activated protein kinases such as MAPKs, ERK and JNK (SAPK) followed by stimulation of at least two well-defined transcription factors NF-KB and AP-1 (c-Fos and c-Jun). Oxidants activate cytosolic and membrane-bound PLA2 activities with the subsequent production of AA metabolites such as HETEs, which subsequently stimulate ERK and JNK (SAPK) activities leading to the activation of transcriptional factors and the ultimate stimulation of the transcription of several mitogen-stress-responsive genes. LacCer, a ceramide analogue present in atherosclerotic plaques, has been found to induce proliferation of aortic smooth muscle cells. LacCer is involved in Ras-GTP loading, activation of kinase cascades (MEK, Raf, p44 MAPK) and c-fos expression. TNF-alpha, on the other hand, induces c-fos, c-myc and c-jun expression. Recent investigations link ceramide and its analogues to the extracellular signal-regulated kinase (ERK) cascade, stress-activated protein kinase-c-Jun kinase (SAPK/JNK) cascade and apoptotic responses. These critical steps in the signalling pathways are sensitive to intracellular thiol-redox and protease(s)-antiprotease(s) status, both of which can be modified by oxidants. Because mobilisation of intracellular Ca2+ caused by a variety of signals also plays a role in the activation of the signalling pathways, an important aspect of future work will be to ascertain the roles of oxidants and Ca2+ individually and in combination in the activation of the signalling pathways. The following two important questions also deserve future attention: (1) How does NF-kB shield cells from apoptotic death? and (2) By what mechanisms does the activated NF-kB cause cellular transformation? Furthermore, the role of AP-1 acting as transcriptional activator seems clear, but the target genes remain to be defined.

Animals↗
PubMed1983

Concentrations of prostaglandin E2 and F2 alpha in the cardiovascular system of infants with persisting patent ductus arteriosus.

The distribution of prostaglandin E2 and F2 alpha was examined in the peripheral veins and in several positions of the cardiovascular system before and after the blood had passed through the lungs in 37 infants. Prostaglandin E2 varied from 0.25 +/- 0.09 ng/ml to 0.44 +/- 0.09 ng/ml when measured in the pulmonary artery, the ductus arteriosus, the right atrium, the right ventricle, the left atrium, the left ventricle, the inferior vena cava and the descending aorta. Prostaglandin F2 alpha was much higher in these positions of the cardiovascular system. The range was 0.99 +/- 0.36 ng/ml to greater than 2.0 ng/ml. The vascular tissues produced virtually identical high amounts of prostaglandin E2 and F2 alpha, but there were no significant differences in prostaglandin E2 and F2 alpha, concentrations, in venous blood as well as in systemic arterial blood. The results suggest that prostaglandin E2 is not responsible for the persisting patency of the ductus arteriosus in infants. There is no explanation for the increased prostaglandin F2 alpha concentrations in these patients.

Aorta, Thoracic↗
PubMed1998

Chaos in the cardiovascular system: an update.

Rhythmic changes of blood pressure, heart rate, and other cardiovascular measures have drawn the attention of several investigators, since these oscillations can shed light onto the activity of the underlying control network. The overwhelming proportion of circulatory variations, however, are not linear, i.e., they do not consist of perfectly rhythmic components. Thus, these fluctuations are more adequately analysed by non-linear techniques, most of which are adopted from chaos theory. A spotlight issue of 'Cardiovascular Research' (Vol. 31, 1996), focused on chaos in the cardiovascular system. This current review outlines today's understanding of this field by presenting the major discoveries and developments which have taken place since then.

Blood Vessels↗
PubMed2003

Physiological or pathological--a role for relaxin in the cardiovascular system?

The omnipresent 6kDa polypeptide relaxin (RLX) is emerging as a multi-functional endocrine and paracrine factor, with a broad range of target tissues that includes the cardiovascular system. Humans and other higher primates have three RLX genes, designated H1, H2 and H3, of which H2 RLX is the major stored and circulating form. Rodents have only two RLX genes: relaxin-1 (equivalent to H2 RLX) and relaxin-3 (equivalent to H3 RLX). The recent cloning of the human RLX receptor (LGR7), a member of the leucine-rich repeat family of G-protein-coupled orphan receptors, and detection of LGR7 gene transcripts in the heart confirm this organ as a target for RLX (H2). However, evidence for production of the ligand within the cardiovascular system is limited, and few studies have clearly identified the physiological effects of RLX on cardiac function. To add to the controversy, serum concentrations and expression of RLX in the heart are elevated in chronic heart failure patients and animal models of cardiomyopathy, implying that RLX may only be a marker for pathological cardiovascular conditions, rather than normal physiology.

Animals↗
PubMed1984

Comparative analysis of circadian rhythms of certain functional indicators of the cardiovascular system in healthy subjects and in patients with ischaemic heart disease.

The circadian rhythm of certain functional indicators of the cardiovascular system was investigated in 141 patients with ischaemic heart disease (IHD), of whom 65 had post-infarction cardiosclerosis and in 26 healthy subjects. The obtained data were processed by an ES-1020 computer according to a special "Cosinor" programme. Specific circadian rhythm was determined of certain haemodynamic indicators, sinus node excitability, impulse conduction, myocardial supply (according to ECG data) and of the blood clotting system. In healthy subjects, the coincidence of the acrophases of circadian rhythms of functional indicators of the cardiovascular system was found; these indicators reached their maximum level during the day and in the evening. In patients with IHD (with prior myocardial infarction as well as without), there were found shifts in the circadian rhythm of bioelectrical processes in the myocardium, with the maximum values shifted to the night and morning hours. These shifts are a consequence of changes in myocardial nutrition and of worsened coronary flow during the day and in the early evening hours, when the patients exhibit also a tendency towards increased activity of the blood clotting system, as well as fibrinolysis depression.

Blood Coagulation↗
PubMed1996

Acute effect of insulin on autonomic regulation of the cardiovascular system: a study by heart rate spectral analysis.

Insulin is suggested to have direct effects on the cardiovascular system but these are not well described. We assessed the possible influence of insulin on autonomic control of heart function. A 2-h hyperinsulinaemic euglycaemic clamp was performed in 10 healthy women (mean age 21.7 +/- 1.3 years), at two different insulin infusion rates: 80 mU m-2 and 400 mU m-2 min-1, in 7 and 3 subjects, respectively. Saline alone was infused in 4 controls. Power spectral analysis (PSA) of heart rate was recorded before and after 90-120 min of insulin infusion, as were blood pressure and heart rate. Although there were no significant changes in heart rate or blood pressure, PSA showed marked reductions of high frequency (HF) bands after insulin (2.60 +/- 0.12 vs 2.09 +/- 0.16 log ms2, p < 0.005), as at both low and high infusion rates (2.46 +/- 0.13 to 2.14 +/- 0.23 log ms2, p < 0.05, and 2.92 +/- 0.18 to 1.98 +/- 0.06 log ms2, p < 0.01, respectively). There were no significant changes of low frequency (LF) bands. Densities at LF and HF did not change significantly in control studies. As HF and LF are considered to reflect parasympathetic and mainly sympathetic control respectively, our observation of an increased LF/HF ratio (0.13 +/- 0.10 vs 0.63 +/- 0.13, p < 0.005) may be considered an index of relative sympathetic predominance induced by insulin infusion. We conclude that insulin affects the cardiovascular system, reducing vagal influence on the heart and inducing a relative hypersympathetic tone.

Adult↗