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PubMed1986

[Status of the cardiovascular system in patients with subacute thyroiditis].

In thirty patients with subacute thyroiditis the authors examined cardiovascular system with the use of the ECG as the most accessible and informative enough method. The clinical and ECG alterations were compared before and after the treatment with glucocorticoids. It was established that the patients with subacute thyroiditis had clinico-electrocardiographic alterations attesting to the presence of myocardiodystrophy. The alterations seen on the ECG mirrorred fully enough the impairment of the cardiovascular system. Myocardiodystrophies associated with subacute thyroiditis undergo reverse development as the remission of the underlying disease is attained as a result of specific therapy with glucocorticoids. This is confirmed by the electrocardiographic findings in the course of the treatment.

Adult↗

PubMed2003

The influence of various physiological challenges on permanent changes to the cardiovascular system.

The concept of fetal programming provides an intellectual framework that links physiological adaptations that occur during development to permanent changes in postnatal regulatory systems. Recent research in the area of cardiovascular programming has highlighted the mechanisms by which these changes exert their effects. The aim of this review is to integrate some of the literature on nutritional changes, exposure to excess glucocorticoids and other challenges during development as they provide support for various mechanisms of programming of the cardiovascular system.

Animals↗

PubMed1985

Response of the rat cardiovascular system to a moderate altitude in connection with endurance training.

The authors investigated whether an altitude of 1,350 m would affect the rat cardiovascular system in the same way as genuine altitude hypoxia and the way it would take effect when combined with endurance training in the form of swimming It was found that 8 weeks spent at this altitude led to an increase in absolute and relative heart weight, to right ventricular hypertrophy, and to increased resistance of the myocardium to acute anoxia. Physical training at a moderate altitude resulted in an increase in the relative weight of the musculature of both the right and the left ventricle and of the septum. Unlike low altitude training, however, growth of the two compartments of the heart was proportional. The resistance of the myocardium of trained animals against anoxia was the same, irrespective of whether they trained at a low or a high altitude. The results show that even a moderate altitude is not a matter of indifference for the rat organism, but that it leads to characteristic manifestations of altitude hypoxia in the cardiovascular system.

Altitude↗

PubMed2002

Effects of electroacupuncture on minimum alveolar concentration of isoflurane and cardiovascular system in isoflurane anesthetized dogs.

The effects of electroacupuncture (EA) on the minimum alveolar concentration (MAC) and on the cardiovascular system were evaluated with dogs under isoflurane anesthesia. Eight healthy male beagles were randomly assigned to six study groups (five heads/group) with washout intervals of 7 ~ 31 days between experiments for recovery and anesthetic clearance. MAC of isoflurane and cardiovascular parameters were determined after EA at nonacupoint and and at acupoints LI-4, SP-6, ST-36 and TH-8. Electroacupuncture for 30 minutes at LI-4, SP-6, ST-36 and TH-8 acupoints lowered the MAC of isoflurane by 17.5 +/- 3.1%, 21.3 +/- 8.0%, 20.5 +/- 8.2% and 15.6 3.1%, respectively (p < 0.05). However, electrical stimulation of nonacupoint did not induce a significant change in MAC of isoflurane. In the cardiovascular system, the ST-36 group did not induce any significant change in cardiovascular parameters. In the TH-8 group, the mean and diastolic arterial pressure and the systemic vascular resistance were decreased. In the LI-4 group, cardiac output and cardiac index decreased after EA. These results indicate that EA at LI-4, SP-6 and ST-36 have advantages in isoflurane anesthesia in terms of reducing the dose of anesthetics and minimizing cardiovascular side effects.

Anesthesia, Inhalation↗

PubMed1999

Effects of non-invasive stimulation of acupoints on the cardiovascular system.

OBJECTIVE: To study the effect of two non-invasive methods to stimulate acupoints on the cardiovascular system. DESIGN: Blind randomized-controlled trial. SETTING: An experimental setting in a university-affiliated hospital. INTERVENTIONS: The subjects (24 healthy male volunteers) were randomized to receive either an active stimulation consisting of pressure on acupoints (P), an active stimulation consisting of stroking along the meridians (S) or a control stimulation (C). MAIN OUTCOME MEASURES: Data on skin blood flow, arterial pressure, heart rate and EKG were recorded continuously from 20 min before stimulation to 30 min after. RESULTS: In P group there was a decrease in systolic arterial pressure, diastolic arterial pressure, mean arterial pressure, heart rate and skin blood flow. These changes were significantly different from those in C group and, as regards diastolic pressure and mean pressure, also from those in S group. There were no significant differences between S and C groups. CONCLUSIONS: Pressure on acupoints can significantly influence the cardiovascular system.

Acupressure↗

PubMed2004

[Hydrogen sulfide as a biologically active mediator in the cardiovascular system].

Recent studies suggest that apart from nitric oxide (NO) and carbon monoxide (CO), hydrogen sulfide (H2S) is another inorganic gaseous mediator in the cardiovascular system. H2S is synthesized from L-cysteine by either cystathionine beta-synthase (CBS) or cystathionin gamma--lyase (CSE), both using pyridoxal 5'-phosphate (vitamin B6) as a cofactor. CBS is the main H2S-producing enzyme in the brain and CSE is involved in H2S formation in the cardiovascular system. H2S induces hypotension in vivo and vasodilation vitro by opening KATP channels in vascular smooth muscle cells. Chronic administration of CSE inhibitor induces arterial hypertension in the rat. In addition, decreased H2S generation has been demonstrated in the vasculature of spontaneously hypertensive rat, in experimental hypertension induced by NO synthase blockade, and in hypoxia-induced pulmonary hypertension, and administration of exogenous H2S donor has significant therapeutic effects in these models. Deficiency of H2S may contribute to atherogenesis in some patients with hyperhomocysteinemia, in whom the metabolism of homocysteine to cysteine and H2S is compromised by vitamin B6 deficiency. Reduced H2S production in the brain was observed in patients with Alzheimer's disease. On the other hand, excess of H2S may lead to mental retardation in patients with Down's syndrome and may be involved in the pathogenesis of hypotension associated with septic shock.

Alzheimer Disease↗

PubMed1985

[Baseball during the growing years: repercussions on the cardiovascular system (echocardiographic evaluation)].

The influence upon the cardiovascular system of a period (21 months) of physical training program for baseball was studied in 40 normal children (aged 8 to 10 years) in an experimental (20) and control (20) group. The echocardiographic changes observed at the end of the period proved to be substantially alike in both groups. The physiopathological involvements linked to the baseball training in the prepubescent age are discussed.

Baseball↗

PubMed1998

Targets of oxidative stress in cardiovascular system.

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.

Animals↗

PubMed1997

Development of a numerical simulation model of the cardiovascular system.

A numerical simulation model of the cardiovascular system has been developed. It consists of a model of the left atrium, the left ventricle, the coronary vascular system, the aorta, the arterial system, and the venous system. The input of the complete model is the elastance (pressure/volume ratio) developed by the left ventricle. The shape of this elastance is constant in different circumstances. Left ventricular (LV) myocardial oxygen consumption and the amount of oxygen offered to the left ventricle can be calculated with the model. The model has been validated using data from a patient suffering from coronary artery disease. The measured clinical hemodynamical waveforms could be fitted to those generated by the model. With the numerical simulation model, it is possible to predict the functioning of the left ventricle under different circumstances. This makes it possible to study in vitro various pathological clinical situations.

Aorta↗

PubMed2003

Circadian rhythm in the cardiovascular system: chronocardiology.

BACKGROUND: We reviewed recent progress in the study of the chronobiological aspects of the cardiovascular system. METHODS: Medline was used as the main search tool, and the full texts of selected papers were obtained. RESULTS: More than 300 references were found, and 52 of them, representing the major findings in this field, were included in the reference list. Results of these studies confirm that most cardiovascular physiological parameters (such as heart rate, blood pressure, electrocardiogram indices) and pathophysiological events (myocardial ischemia/infarction, sudden cardiac death) show circadian rhythms. Results also suggest that consideration of these rhythms is important for the diagnosis and treatment of cardiovascular disorders and that restoration of normal circadian rhythms may be associated with clinical improvement. CONCLUSION: The study of circadian rhythms in the cardiovascular system is emerging as an important area of investigation because of its potential implications for patient management.

Arrhythmias, Cardiac↗

PubMed2006

Thiol-based mechanisms of the thioredoxin and glutaredoxin systems: implications for diseases in the cardiovascular system.

Reactive oxygen species (ROS) and the cellular thiol redox state are crucial mediators of multiple cell processes like growth, differentiation, and apoptosis. Excessive ROS production or oxidative stress is associated with several diseases, including cardiovascular disorders like ischemia-reperfusion. To prevent ROS-induced disorders, the heart is equipped with effective antioxidant systems. Key players in defense against oxidative stress are members of the thioredoxin-fold family of proteins. Of these, thioredoxins and glutaredoxins maintain a reduced intracellular redox state in mammalian cells by the reduction of protein thiols. The reversible oxidation of Cys-Gly-Pro-Cys or Cys-Pro(Ser)-Tyr-Cys active site cysteine residues is used in reversible electron transport. Thioredoxins and glutaredoxins belong to corresponding systems consisting of NADPH, thioredoxin reductase, and thioredoxin or NADPH, glutathione reductase, glutathione, and glutaredoxin, respectively. Thioredoxin as well as glutaredoxin activities appear to be very important for the progression and severity of several cardiovascular disorders. These proteins function not only as antioxidants, they inhibit or activate apoptotic signaling molecules like apoptosis signal-regulating kinase 1 and Ras or transcription factors like NF-kappaB. Thioredoxin activity is regulated by the endogenous inhibitor thioredoxin-binding protein 2 (TBP-2), indicating an important role of the balance between thioredoxin and TBP-2 levels in cardiovascular diseases. In this review, we will summarize cardioprotective effects of endogenous thioredoxin and glutaredoxin systems as well as the high potential in clinical applications of exogenously applied thioredoxin or glutaredoxin or the induction of endogenous thioredoxin and glutaredoxin systems.

Animals↗

PubMed1992

Dynamic properties of cardiovascular systems.

A recently derived mathematical model of an isolated heart is extended here to a closed-loop cardiovascular system. Taking the end-diastolic volume as state variable, the authors show that the closed-loop cardiovascular system can be described by a one-dimensional nonlinear discrete dynamical system that depends on parameters describing the systolic and diastolic properties of the heart, heart rate, total peripheral resistance, and arterial capacitance. Studies of this model show that the system possesses a rich spectrum of dynamical behavior, from stable points through stable cycles to a "chaotic" behavior. It is shown that such an analysis of dynamic behavior yields those domains in the parameter space that correspond to a normal and abnormal beating heart, when the heart ejects time-invariant and time-variant (periodic or aperiodic) stable stroke volumes, respectively. Determination of such domains may lead to better understanding of the specific pathologic mechanism involved in the evolution of an abnormal beating heart.

Cardiovascular Physiological Phenomena↗

PubMed2006

Simulating transient ventricular interaction using a minimal cardiovascular system model.

A minimal closed-loop cardiovascular system (CVS) model has been developed that can simulate ventricular interaction due to both direct interaction through the septum and series interaction through the circulation system. The model is used to simulate canine experiments carried out to study the transient response of the left ventricle due to changes in right ventricle pressures and volumes. The model-simulated trends in left and right ventricle pressures and volumes, septum deflection and arterial flow rates are compared with the experimental results. In spite of the limited physiological data available describing the animals, the model is shown to capture all the transient trends in the experimental data. This is the first known example of a physiological model that can capture all these trends. The model is then used to illustrate the separate effects of direct and series interactions independently. This study proves the value of this modelling method to be used in conjunction with experimental data for delineating and understanding the factors that contribute to ventricular dynamics.

Animals↗

PubMed2004

[Effects of the hormone replacement therapy on cardiovascular system, bone mass and memory in climacteric patients].

OBJECTIVE: To evaluate the effect of the hormone replacement therapy type estradiol-medroxyprogesterone and tibolona on cardiovascular system, bone mass and memory in the climacteric patients. PATIENTS AND METHOD: From January through December 2001 at the Specialties Hospital No. 1, we included 77 consecutive climacteric patients. They were divided in 2 groups: premenopause in treatment with estradiol-medroxyprogesterone and postmenopause with tibolona. We studied cardiovascular system, the bone mass and memory. The statistical analysis was by means of t Student for difference between the groups. RESULTS: With the estradiol-medroxyprogesterone use, the blood pressure diminished significaticantly just for systolic pressure (-10.22/-6.38 mmHg). Cholesterol and triglyceride, both diminished significantly (-43.92 mg and -58.79 mg). There is not significance for the bone mass of lumbar-spine and femoral neck (+0.68% and +0.69%) as neither in the memory test (20-22). With the tibolona use, the blood pressure was not reduced significantly (-6.93/-1.94 mmHg), with single significant reduction for cholesterol (-25.83 mg and -18.15 mg), presenting bone mass significant improvement just for femoral neck (+0.13% and +0.84%) and without improving in the memory test (17-18). CONCLUSIONS: A diminution of lipids with the estradiol-medroxyprogesterone use, as well as reduction of the cholesterol and improvement of the bone mass with the tibolona use but without benefits in the memory test with both treatments.

Adult↗

PubMed2002

Lysophospholipids and the cardiovascular system.

The lysophospholipids sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA) have varied effects on the cardiovascular system. S1P is necessary for normal vascular development and may play an important role in angiogenesis. These molecules may exert potentially detrimental effects. Both S1P and LPA are released from activated platelets and can in turn stimulate platelet aggregation. These thrombogenic effects would further enhance ischemia in acute coronary syndromes and myocardial infarction. LPA is a major component of the lipid core of human atherosclerotic plaques and can stimulate vascular smooth muscle proliferation. Both LPA and S1P cause cardiac myocyte hypertrophy in vitro. Beneficial effects include cardioprotection both in vitro and during ischemia/reperfusion in an ex vivo whole heart mouse model. Understanding both the acute and the chronic physiologic and pathophysiologic roles of the lysophospholipids and their cognate receptors and signaling pathways in the cardiovascular system, which are likely to be species-, tissue-, and cell-specific, may allow the development of molecules that can be targeted to stimulate or inhibit a specific function.

Animals↗

PubMed2005

Prostacyclin in the cardiovascular system: new aspects and open questions.

Several indications exist that prostacyclin (PGI(2)) release in the cardiovascular system might be affected by cyclooxygenase (COX)-2-specific inhibitors. This could reflect an inhibition of PGI(2) synthesis in the endothelium although in these cells mainly COX-1 is expressed. Inflammation and stress induce COX-2 in smooth muscle cells which could have happened in patients with cardiac diseases. Herein, we show that also cardiomyocytes contain PGI(2) synthase in intercalated discs as a third source of PGI(2) in the cardiovascular system. Another aim of this study was to explain the finding that PGI(2) synthase in lipopolysaccharide (LPS)-treated smooth muscle cells, in contrast to endothelial cells, is resistant to nitration and inhibition by peroxynitrite. By using redox cyclers, the nitration occurred and confirmed our previous hypothesis that a high peroxidative activity of such cells keeps peroxynitrite below the effective levels of 50 nM. Considering enhanced oxidative stress in aged vessels, we postulated and verified that endothelial dysfunction in aged vessels is due to nitration and inhibition of PGI(2) synthase. Such data underline the role of PGI(2) as a potent mediator for regaining and maintaining the normal resting state of cells in a COX-2 dependent fashion.

Aging↗

PubMed1992

The rat dopamine D4 receptor: sequence, gene structure, and demonstration of expression in the cardiovascular system.

Dopamine receptors have been implicated in a variety of neurological and neuropsychiatric disorders. Here we describe the use of the polymerase chain reaction and low stringency library screening to isolate a rat genomic clone encoding a novel dopamine receptor. Sequence data and pharmacological analysis reveal this clone to be the rat analog of the human D4 receptor, which exhibits a high affinity for the antipsychotic drug clozapine. The mRNA for this receptor shows a restricted pattern of expression in the central nervous system. Significant levels of expression were found in the hypothalamus, thalamus, olfactory bulb, and frontal cortex. However, 20-fold higher levels of D4 mRNA expression were observed in the cardiovascular system. Thus, this receptor appears to mediate dopamine function in the cardiovascular system as well as the central nervous system.

Amino Acid Sequence↗

PubMed1991

Direct effect of hypoglycemic sulphonylureas on the cardiovascular system of dogs.

The effects of first generation sulphonylurea compounds carbutamide, gliclazide and tolbutamide as well as second generation compounds glibenclamide and glipizide on the cardiovascular system were investigated in dogs. Six dogs received each compound intravenously at cumulative dose levels of 74, 296, 1184 mumol/kg of carbutamide and tolbutamide, 0.4, 2.0, 10.0 mumol/kg of glibenclamide and glipizide, and 16, 48 and 144 mumol/kg of gliclazide. Mean arterial blood pressure, myocardial contractile force, cardiac output and heart rate were measured. The rate of change of myocardial contractile force development (positive dF/dt), as well as of myocardial relaxation (negative dF/dt) were measured. The first generation sulphonylureas were found, in dogs, to exert a positive inotropic effect in contrast to second generation compounds. The clinical importance of our findings may be in the potential for the malfunction of the cardiovascular system (based on cardiopathy, neuropathy, atherosclerosis, and obesity), developing in diabetes, to be further impaired by the first generation sulphonylureas. Therefore, second generation sulphonylureas should be preferred in the therapy of type 2 diabetics, if satisfactory metabolic control cannot be achieved by dietary management alone and sulphonylurea treatment becomes necessary.

Animals↗