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At least 271 records · Page 15Linked to original sources
PubMed1983

Arterial bifurcations in the cardiovascular system of a rat.

Arterial bifurcations in the cardiovascular system of a rat were studied, using a resin cast of the entire arterial tree. At each bifurcation, measurements were made of the diameters of the three vessels involved, the two branching angles, and the angle delta, which the parent artery makes with the plane containing the two branches. The results were found to be consistent with those reported previously in man and monkey. In addition, measurements of delta in the present study indicate that arterial bifurcations are mostly two dimensional.

Animals↗
PubMed1984

The nuclear uptake and retention of a synthetic progestin in the cardiovascular system of the baboon.

It has long been known that there is a sexual dimorphism in the incidence of coronary heart disease. This observation, together with more recent reports of increased cardiovascular disease associated with the use of oral contraceptives, led to a search for steroid receptors in the cardiovascular system. In this study we examined the nuclear uptake and retention of a synthetic progestin in the cardiovascular system of the baboons. Long term oophorectomized baboons were primed with estradiol benzoate for 3 days before the experiment (50 micrograms/kg, im) and adrenalectomized 2 days before the experiment. On the day of the experiment, the animals were injected under anesthesia with 2.5 micrograms/kg BW [3H]ORG 2058 (16 alpha-ethyl-21-hydroxy-19-nor-[6,7-3H]pregn-4-ene-3,20-dione) or with [3H] ORG 2058 plus a 1000-fold excess of unlabeled progesterone (control). One hour after the injection, the animals were rapidly exsanguinated, and parts of the cardiovascular system were removed and processed for autoradiography. Localization of the synthetic progestin was found in nuclei of between 25-75% of all smooth muscle cells of the media of all arteries examined and to a lesser extent in the nuclei of the fibroblasts and others cells of the adventitia. Localization of the synthetic progestin in the heart was limited to approximately 1% of the myocardial cells and less than 5% of interstitial cell nuclei. The pattern of localization found differs from that for estrogen and androgen and suggests the possible presence of estrogen-independent progesterone receptors in smooth muscle cells of the media of the aorta and coronary arteries.

Adrenalectomy↗
PubMed1984

Systemic cardiovascular effects of intracranial disorders: implications for nursing care.

Autonomic nervous system imbalances are implicated in the genesis of cardiovascular systemic effects of brain disorders. With many potentially lethal cardiovascular problems, sympathetic predominance over parasympathetic stimuli prevails. Autonomic nervous system imbalances may be caused not only by over-activity or depression of either the sympathetic or parasympathetic nervous systems but also by unchanged activity of one and depression or overactivity of the other. Because the autonomic nervous system has representation in all levels of the brain, it becomes apparent why diverse brain disorders could trigger these effects. It is possible that more than one systemic effect may occur in a patient during the course of an acute brain insult. The hypothalamus, with its anterior parasympathetic nervous system centers and posterolateral sympathetic nervous system centers, plays an important role in the autonomic nervous system. Its role has been more clearly identified than other portions of the central autonomic system. Nursing implications for the care of patients with cardiovascular effects have been identified. Many of these effects may go unnoticed in the early stages because of lack of knowledge; consequently, opportunities for early therapeutic interventions are lost to the detriment of the patient. These effects, when unrecognized and untreated, compound the primary and secondary intracranial insults. They can contribute to the rapid deterioration and demise of the patient, especially if he is unstable and has lost intracranial compliance, autoregulation, and vasomotor tone. Because many of these patients, have had no evidence of cardiovascular problems prior to the acute brain insult, it behooves nurses to familiarize themselves with the signs and symptoms of the systemic cardiovascular effects and appropriately intervene to prevent or offset the complications they produce in the acutely brain-damaged patient.

Arrhythmias, Cardiac↗
PubMed1997

Effects of inhaled albuterol and ipratropium bromide on autonomic control of the cardiovascular system.

STUDY OBJECTIVE: Systemic administration of beta-agonist and anticholinergic drugs markedly impair normal autonomic heart rate control. The purpose of this study was to quantify and compare the effects of therapeutic doses of inhaled albuterol and ipratropium on autonomic control of the cardiovascular system. DESIGN: Randomized, double-blind, placebo-controlled, crossover design study. SETTING: Tertiary-care hospital. SUBJECTS: Twelve healthy male volunteers. INTERVENTIONS: Subjects self-administered four puffs through a spacer device from one of three identical inhalers containing albuterol (100 microg per puff), ipratropium (20 microg per puff), or placebo in three different testing sessions. MEASUREMENTS: ECG and noninvasive continuous BP traces were recorded at baseline and from 45 to 75 min after administration of the drug. Autonomic control of the cardiovascular system was quantified by analysis of spontaneous baroreflex sensitivity and power spectral analysis of heart rate variability. RESULTS: Neither albuterol nor ipratropium caused a significant alteration in baroreflex sensitivity, normalized low-power frequency, or normalized high-power frequency. No adverse effects were reported by subjects. CONCLUSIONS: Inhalation of four puffs of albuterol (400 microg) or ipratropium (80 microg) does not alter the autonomic control of the cardiovascular system in young, healthy male subjects.

Administration, Inhalation↗
PubMed2001

[The comparison of selected parameters of structure and function of the cardiovascular system in patients with functioning graft on maintenance hemodialysis during a one year period].

Successful renal transplantation allows to correct most of the abnormalities that lead to cardiovascular system injury in chronic uremia. The aim of the present study was to analyze selected anatomical and functional parameters of the heart using echocardiography. The study was conducted prospectively in two groups of patients: 73 subjects with functioning graft and 53 patients on maintenance hemodialysis. Obtained results were compared between those two groups at the start of the study and later on after 6 and 12 months of follow-up. Post-transplant patients were included into the study 11 +/- 6.4 months after successful transplantation. Mean dialysis period prior to transplantation was 35 +/- 21 months. Patients in the control group were dialyzed for mean 54 +/- 25 months. The prevalence of various diseases of the cardiovascular system was equal in both groups of patients (most frequently diagnosed was hypertension). There was no difference in ejection fraction within groups during the whole study period, however the value of this parameter was higher among patients with functioning graft at the beginning of the study (p < 0.01) as well as after 6 and 12 months (p < 0.001) as compared to patients on dialysis. The prevalence of different morphological abnormalities of the heart, such as concentric hypertrophy, left ventricle dilatation, valve dysfunction as well as calcification of various structures, was equal in both groups of patients at the beginning of the study. In 87.7% of patients with functioning graft, left ventricle hypertrophy was diagnosed at the beginning of the study (mean LVMI value 176.9 +/- 55.5 g/m2) and this percentage decreased to 63% after 6 months (LVMI 155.8 +/- 60.3 g/m2; p < 0.001 vs. baseline) and 53.4% after 12 months (LVMI 141.6 +/- 62.1 g/m2; p < 0.001 vs. baseline). Regression of initial left ventricle hypertrophy, although less pronounced was also present among patients on maintenance dialysis. There was no difference in LVMI value between the studied groups at the beginning of the study, whereas after 6 and 12 months of observation it became significantly lower in patients with functioning graft (155.8 +/- 60.3 vs. 179.5 +/- 50.9 g/m2; p < 0.01 and 141.6 +/- 62.1 vs. 176.2 +/- 50.5 g/m2; p < 0.001). Based on obtained results we conclude that successful renal transplantation promotes the normalization of a number of echocardiographic parameters, especially leads to regression of left ventricle hypertrophy. Renal transplantation seems to be an optimal method of treatment in patients with end-stage renal failure, considering structure and function of the cardiovascular system.

Adult↗
PubMedDate not supplied

Effects of pituitary adenylate cyclase activating polypeptide (PACAP) and vasoactive intestinal polypeptide (VIP) on the cardiovascular system in sheep.

The cardiovascular effects of PACAP and VIP were studied in intact conscious sheep; PACAP (0.008, 0.04, 0.2, and 1.0 nmol/min) and VIP (0.07, 0.2, 0.6, and 1.8 nmol/min) were infused in conscious sheep for periods of 10 min. For each peptide there was a dose-dependent increase in heart rate. At the highest doses tested, pulse pressure and mean arterial pressure tended to increase and decrease, respectively. However, only the decrease in mean arterial pressure following the highest dose of VIP reached significance. At the highest doses tested, heart rate increased nearly threefold during the infusion while mean arterial pressure declined by 18.5%. In individual animals the decrease in blood pressure and increase in heart rate occurred simultaneously, so that we were unable to conclude whether the increase in heart rate was due to a baroreceptor reflex.

Animals↗
PubMed1984

Acute effect of maternal smoking on the maternal and fetal cardiovascular system.

Maternal and fetal cardiovascular dynamics were studied in relation to maternal smoking in 18 healthy nulliparous subjects randomly divided into a smoking (n = 9) and a control group (n = 9) between 34 and 38 weeks of gestation. At the end of the study, data from 7 smokers and 7 controls were available for analysis. A significant rise in maternal heart rate and systolic blood pressure was observed during and following smoking one cigarette. A significant increase in fetal heart rate occurred following smoking, whereas mean blood flow velocity and vessel diameter in the fetal descending aorta as measured by pulsed Doppler and time motion techniques did not demonstrate any significant changes.

Aorta↗
PubMed1992

Measurement of blood flow and perfusion in the cardiovascular system.

Complete evaluation of cardiovascular disease by a single imaging technique requires measurement of bulk flow in blood vessels and estimation of relative or ideally absolute perfusion at the tissue level. Magnetic resonance (MR) measurement of blood flow in arteries and veins has been done using the velocity-encoded phase cine gradient echo technique. This technique has been applied with cine MR to measure normal and pathologically high velocities. Measurement of relative perfusion in the myocardium has used the intravenous injection of T1 relaxation enhancing and magnetic susceptibility MR contrast media with rapid image acquisition using echoplanar imaging. MR images (MRIs) acquired during steady-state distribution or during the first passage of these contrast media have depicted ischemic myocardial regions.

Animals↗
PubMed1978

Pathology of centerarians. I. The cardiovascular system and lungs.

The cardiovascular and lung lesions in 23 centenarians (7 males and 16 females) were examined pathologically. The heart showed varied degrees of hypertrophy, and myocardial fibrosis was present in 15 of the 23 patients. Coronary arteriosclerosis was noted coincidentally. In addition to these findings, amyloid deposition was seen in the hearts of 8 patients. Generalized atherosclerosis of the arterial tree was severe to moderate in all cases. Bronchopneumonia was present in 15 of the 23 patients, and fresh or old thromboembolism in 8. There was a tendency toward emphysema and chronic bronchitis in the structure of the lung. The frequent occurrence of myocardial fibrosis and bronchopneumonia was characteristic in the series. It was significant that cardiac amyloid deposition was noted in these cases.

Aged↗
PubMed1991

Pharmacological profile of the 2-alkynyladenosine derivative 2-octynyladenosine (YT-146) in the cardiovascular system.

We investigated the cardiovascular effects of 2-octynyladenosine (YT-146), an adenosine A2 agonist, in various mammalian preparations in comparison with adenosine and 2-chloroadenosine. YT-146, when intravenously administered, caused a dose-dependent decrease of blood pressure in anesthetized normotensive rats (with ED30 values of 0.4 micrograms/kg), and YT-146 was 250 times more potent than adenosine. Whereas adenosine and 2-chloroadenosine decreased heart rate at approximately equihypotensive doses, YT-146 had no negative chronotropic effects at h hypotensive doses. Orally given YT-146 (0.1 - 1 mg/kg) produced a potent and long-lasting antihypertensive effect in spontaneously hypertensive rats. YT-146 was 15.9 and 12.5 times more potent than adenosine in producing relaxation of isolated porcine coronary arteries and in increasing dog coronary blood flow, respectively. Although YT-146 was equipotent to adenosine in causing a negative inotropic effect in isolated guinea pig atria, it was less potent than adenosine in producing atrioventricular conduction block in guinea pigs. On the other hand, 2-chloroadenosine was 9.1, 1.8 and 2.4 times more potent than adenosine in lowering blood pressure, relaxing isolated porcine coronary arteries and increasing dog coronary blood flow, respectively. 2-Chloroadenosine was the most potent in producing cardiodepression, i.e., negative inotropy and atrioventricular conduction block in guinea pigs. From these results, we concluded that YT-146 is a potent coronary vasodilator and also a potent, orally active and long-acting hypotensive agent having less cardiac depressant activity.

Adenosine↗
PubMed1988

The influence of high thoracic epidural analgesia on the cardiovascular system.

The effect of high thoracic epidural analgesia (TEA) on the cardiovascular system was investigated in 10 patients (5 with cardiovascular disease and 5 without known cardiovascular disorder), who were scheduled for a thoracotomy. An epidural catheter was inserted at T1-T2 level. Plain bupivacaine (Marcaine) 0.5%, 4 to 6 ml was used and resulted in a mean analgesic level from C7 to T5. TEA did not significantly affect the following parameters: heart rate, mean arterial pressure, cardiac index, central venous pressure, pulmonary capillary wedge pressure, stroke volume index, systemic vascular resistance, pulmonary vascular resistance, right and left ventricular stroke work index. From this study it is concluded that high TEA with bupivacaine has only minor effects on the cardiovascular system.

Anesthesia, Epidural↗
PubMed1993

Acute opioid dependence in the cardiovascular system of the spinal rat.

This article analyzes and characterizes the early development of opioid dependence in the cardiovascular system of the spinal rat. The main part of the study deals with changes in mean arterial pressure and heart rate induced by naloxone (NLX) in spinal rats pretreated with single doses of morphine. The results show that the cardiovascular system of the spinal rat is highly sensitive to the abstinence-precipitating actions of NLX after a single dose of morphine. Dose-response curves for precipitated abstinence evaluated as changes in mean arterial pressure and heart rate show a gradual increase in maximum followed by a progressive shift to the left as dependence progresses. Cardiovascular abstinence is mostly mediated by catecholaminergic systems. NLX also precipitates noncardiovascular signs of abstinence. Interestingly, morphine-free spinal rats gave some abstinence-like responses to NLX, probably because of endogenous release of opioids. The spinal rat seems to be a valuable system for a rapid quantitative pharmacological characterization of the abstinence-precipitating actions of opioid antagonists and for the study of the changes that occur during the acute development of opioid dependence.

Animals↗
PubMed1996

Adverse effects of interferon on the cardiovascular system in patients with chronic hepatitis C.

The therapeutic effects of interferon in chronic hepatitis C and many of its adverse effects have been well documented. However, there are only a few reports regarding its adverse effects on the cardiovascular system. The aim of this study was to clarify the clinical features of the adverse effects of interferon on the cardiovascular system in patients with chronic hepatitis C. We monitored 295 patients with chronic active hepatitis C during 312 courses of interferon therapy and for 1 year after the end of treatment for the presence of cardiovascular adverse effects. We found 6 patients with cardiovascular adverse effects during interferon therapy and 4 more patients within 1 year after the end of therapy (10/312, 3.2%). The adverse effects of interferon on the cardiovascular system included arrhythmia (n = 4), ischemic heart disease (n = 4) and myocardial disease (n = 2). None of the clinical factors, including history of cardiovascular disease, were related to these cardiovascular adverse effects. In all instances the patient's condition improved after discontinuation of interferon and adequate therapy. The cardiovascular adverse effects of interferon occurred frequently in patients with chronic hepatitis C, even after the end of therapy and they were unpredictable. Thus, all patients undergoing interferon therapy should be monitored not only during but also after the end of treatment.

Arrhythmias, Cardiac↗
PubMed1977

Shear forces and blood vessel radii in the cardiovascular system.

What mathematical or physiological principles govern the radii of blood vessels in the cardiovascular system and by what mechanisms are those principles implemented? This question is studied in the contexts of fluid dynamics and physiology of the cardiovascular system, and a possible answer is examined in the light of empirical data.

Animals↗