A simplified, reverse-phase HPLC method utilizing a metal-free column was developed for the analysis of cyclosporin (CYA) in whole blood in humans. The average intra and inter assay variation at the low end of the therapeutic range are less than or equal to 4.5 and 8.8% respectively. The procedure was ...

Controlled hypotension was induced in pigs by the infusion of adenosine, sodium nitroprusside (SNP) or nitroglycerin (TNG). Central and regional haemodynamics were studied using the microsphere technique during control and hypotensive periods. All three drugs produced decreases in mean arterial pressure (MAP), but it was very difficult to maintain stable ...

To determine whether the reported absence of fever in full-term-pregnant ewes might be associated with shifts of regional blood flows from thermogenic tissues to placenta during this critical period, fevers were induced twice by injections of Escherichia coli lipopolysaccharide (LPS, 0.25 microgram/kg iv) into each of six Merino ewes from ...

Cardiac output was determined with an indicator dilution technique during digital venous angiography of the left ventricle in 11 patients. The contrast medium injected into the right atrium was used as indicator. During and after the injection of contrast medium one blood sample per second was obtained through a catheter ...

Freshwater-acclimated rainbow trout were chronically and non-occlusively cannulated in the dorsal aorta (DA), sinus venosus (SV) and branchial vein (BV), the latter returning the blood perfusing the central venous sinus (CVS) of the gill after being shunted away from the systemic circuit. After recovery, blood samples from these three sites ...

Cardiac output (QAo) can be estimated noninvasively by pulsed Doppler (PD) ultrasonographic determination of mean ascending aortic blood flow velocity (VAo) combined with M-mode echocardiographic determination of ascending aortic cross sectional area (AAo). Cardiac output is calculated from the volumetric flow equation (QAo) = (VAo) X (AAo). Pulsed Doppler measurements ...

We studied the haemodynamic effects of clonidine (2 micrograms/kg/iv) in 7 tetraplegics and 7 normal subjects. Measurements of blood pressure, stroke volume, cardiac output and digital (finger) skin blood flow were made before and after clonidine for 60 minutes. Blood pressure, stroke volume and cardiac output did not fall in ...

The cardiovascular adaptations to chronic anemia were studied in the newborn lamb and then compared with the adaptations to chronic hypoxemia. Eight chronically instrumented newborn lambs underwent repeat isovolemic exchange transfusions to maintain their Hb concentrations at 60% of normal for age. Hemodynamic studies were performed twice weekly for 2 ...

Changes in finger blood flow, arm blood flow and cardiac output were measured using electrical impedance plethysmography in 20 patients after brachial plexus anaesthesia. The anaesthetic solution used in all patients was 1% lignocaine with adrenaline 1:200,000. Significant increases in cardiac output and blood flow to the unanaesthetised arm were ...

This study determined whether noninvasive electrical impedance cardiography accurately measures systemic blood flow (cardiac output) in children with congenital heart defects. A total of 37 patients ranging in age from 2 to 171 months underwent complete right- and left-sided heart catheterizations that included simultaneous Fick and impedance measurement of cardiac ...

Radiolabeled microspheres are commonly used to measure cardiac output and regional blood flow distribution in small animals such as rats. By using batches of microspheres labeled with different nuclides, several flow measurements can be made in the same animal. A protocol and computer program for analyzing data from multiple nuclide ...

Tissues are usually considered as being supply-dependent (e.g., heart and brain) and supply-independent (e.g., splanchnic area, kidneys, skin, and resting muscle) for oxygen delivery. When cardiovascular function is compromised, circulatory compensations are aimed at maintaining supply-dependent tissues. In the long term, this leads to the possibility of an inadequate blood ...

1. Cardiac output and its distribution to the mammary gland, kidneys, heart, liver and gastrointestinal tract were measured in conscious rabbits at day 1, day 3 and day 6 after removal of the young at day 0. 2. There was no change in cardiac output, proportion of cardiac output delivered ...

Nitrendipine and cilazapril are two new antihypertensive drugs with different mechanisms of action. Nitrendipine is a calcium antagonist of the dihydropyridine class which decreases directly the smooth muscle tone. Cilazapril is a new long-lasting inhibitor of angiotensin-converting enzyme which suppresses the peripheral vasoconstrictor effect of angiotensin I by inhibiting its ...

The central and peripheral haemodynamic effects of pulmonary embolisation with microspheres were measured in conscious rabbits in which the autonomic and central nervous systems were functioning normally. Sufficient microspheres were given to reduce cardiac output (measured by thermodilution) by one half. This fall in cardiac output was accompanied by a ...

A preliminary Pulsatile Flow Bench validation of the REF-1 Right Ventricular Ejection Fraction (RVEF) computer and catheter system was performed to determine the accuracy of the current REF-1 system. These results reflect the accuracy of the current REF-1 system and not the final REF-1 system that will be released at ...

This study describes the effects of beta-receptor blockade on systemic hemodynamics and regional blood flows during acute ischemic heart failure in dogs. Depression of left ventricular (LV) function was induced by embolization of the left main coronary artery and was evidenced by a significant increase in LV end-diastolic pressure (LVEDP) ...

The authors have shown that systemic activation of the complement system with either zymosan or cobra venom factor produces some of the hemodynamic changes characteristic of sepsis, specifically, a reduction in hepatic perfusion despite a normal or hyperdynamic systemic circulation. This study was undertaken to determine whether complement activation accompanied ...

This study has investigated the flow of blood to the adrenal gland of the anaesthetised rat under basal conditions and after the induction of haemorrhagic hypotension. By combining the use of radioactive microspheres with subsequent serial sectioning we have been able not only to assess total adrenal blood flow but ...

We have studied the effects of captopril, nitrates and dobutamine on hemodynamics and regional blood flow in the conscious rabbit with adriamycin cardiomyopathy. Rabbits were injected twice weekly with adriamycin (1 mg.kg-1 bw.) for 8 weeks and subsequently maintained for 2 weeks without adriamycin in order to allow recovery from ...

The new angiotensin converting enzyme inhibitor, spirapril, was found to inhibit the pressor effects of angiotensin I about 10 times more potently than captopril in conscious rabbits. Its effects on systemic hemodynamics and regional blood flows were studied in two groups of 8 normotensive anaesthetized rabbits pretreated 24 h before ...

Redistribution of regional blood flow is an important compensatory response to acute hypoxemia which preserves oxygen delivery to the most vital organs. It is not known if this change in blood flow persists when hypoxemia is prolonged, as occurs in cyanotic congenital heart disease. Chronic hypoxemia was produced in newborn ...

Traditionally, cardiovascular adjustments to hypoxaemia are viewed as resultants of competing local vasodilation and vasoconstriction via arterial chemoreflexes with net effects of increased cerebral and coronary blood flows (local) and reduced flow to visceral organs and muscle (reflex). Although true in asphyxia, breathing activates lung mechanoreceptors which reduce vagal outflow ...

The acute effects of the beta 1-adrenoceptor inhibition by atenolol were investigated on conscious rats. Cardiac output and organ blood flow were measured by 15-microns radiolabelled microspheres during control and 20 min after administration of atenolol (1 mg/kg body wt). Arterial blood pressure and heart rate were measured continuously. Arterial ...

Effects of 1.1, 1.5, and 1.8 minimal alveolar concentration (MAC) isoflurane-O2 (1.45%, 1.96%, and 2.39% end-tidal isoflurane, respectively) anesthesia on cardiac output, blood pressure, and blood flow to the brain, thyroid glands, adrenal glands, kidneys, and splanchnic organs were examined in 9 healthy isocapnic adult ponies. Tissue blood flows were ...

We studied left ventricular (LV) cardiac output as estimated by ascending aorta blood flow (QAo) longitudinally in 31 healthy infants from birth through the first year of life using noninvasive pulsed Doppler ultrasound technique. The temporal mean ascending aortic blood flow velocity (VAo) was measured with a 5-MHz pulsed Doppler ...

Laser Doppler flowmetry (LDF) accurately measures cutaneous microcirculatory blood flow. We compared change in LDF flow to change in thermodilution cardiac output in ten critically ill surgical patients. A subset analysis of three patients with low cardiac output (cardiac index less than 2 L/min X m2) showed no correlation. We ...

Radiant heat is known to increase insensible water loss and, to a certain extent, oxygen consumption. Little is known about its cardiovascular effects. We measured cardiac output, stroke volume, heart rate, and lower limb and skin blood flow in 20 preterm newborn infants nursed in an incubator and under a ...

Cardiac output, central haemodynamics and regional blood flows were studied in pigs. The microsphere technique was used for blood flow determinations. Measurements were made during spontaneous breathing (SB) and during intermittent positive pressure ventilation with 0.8 kPa (8 cmH2O) positive end-expiratory pressure (8 PEEP) before and during thoracic epidural analgesia ...

We determined the regional blood flow responses to head-out water immersion (WI) in intact (INT) and cardiac-denervated (CD) conscious dogs. Immersing dogs in thermoneutral water (37 degrees C) in the quadruped position for 100 min resulted in significant increases in cardiac output (Qco) above control values by 38.7% in the ...

Cardiac output, organ blood flow and organ weights were examined in rats assigned at d 0 of lactation to a control (C) group fed ad libitum or an acutely restricted (AR) group fed 50% of the intake of C dams. Dams in each group were assigned to subgroups for measurement ...

The systemic and regional hemodynamic effects of ketanserin were investigated in spontaneously hypertensive rats (SHRs) using either the pulsed Doppler or the microsphere technique. In addition, the contribution of ketanserin alpha 1-adrenoceptor blocking properties to these hemodynamic effects was assessed. Ketanserin, directly after infusion or secondarily after bolus injection, induced ...

Elevated intraabdominal pressure (IAP) occurs with intraabdominal bleeding, with tense ascites, or after application of military anti-shock trousers to trauma patients. While changes in renal perfusion with elevated IAP have been documented, there are no data available on blood flow to other viscera. Under pentobarbital anesthesia an inflatable bag was ...

Intravenous infusion of leukotriene D4 (LTD4; 0.1-10 micrograms/kg) produced dose-related depression of myocardial contractility, stroke volume index and mean aortic blood flow index in anesthetized monkeys. These alterations occurred in association with increments in systemic and pulmonary vascular resistances, reductions in calculated left ventricular stroke and minute work indices and ...

Heart rate, stroke volume, cardiac output, its distribution and organ blood flows were measured, using the microsphere technique (15 micron in diameter microspheres), in 5, 12 and 24 months old conscious male rats. Each rat was then infused with isoproterenol (0.2 microgram/kg.min) and the measurements were repeated. It was found ...

We compared the effects of protein, carbohydrate, or water ingestion on human renal blood flow (RBF) and cardiac output (CO). We validated and applied a noninvasive ultrasonic Doppler method to measure blood velocities and lumen diameters in the right renal artery and the ascending aorta of five healthy adults. From ...

Pressure and flow relationships to the head were measured before and during spaceflight by means of a chronically implanted cuff placed about the left common carotid artery in one of two rhesus monkeys flown aboard Cosmos 1514. Measurements were obtained daily for 4 min every 2 h during the 5-d ...

The relationship between the spontaneous hematocrit (Hct) and maternal hemodynamics and the hemodynamic effects of experimentally induced changes in this Hct were studied in the awake late-pregnant guinea pig. In animals with a relatively low Hct, cardiac output fractions and blood flows to brain and heart determined with microspheres were ...

This study was designed to examine the total body hemodynamics of abdominal aortic coarctation hypertension. The study quantitates both regional and organ blood flow and resistance in conscious rats both above and below an experimentally produced coarctation. The experimental group consisted of 10 male Sprague-Dawley rats with a mean pressure ...

Infusion of the peptide secretin augments cardiac output due to vasodilating and inotropic properties. The aim of this investigation was to study how the increased cardiac output is distributed in the peripheral circulation. Before, during and after 15 min infusion of secretin 64 CU kg-1 h-1 flow changes in renal, ...

Calcitonin gene-related peptide, a 37-amino-acid neuropeptide, has been shown to be widely distributed in periadventitial nerves throughout the cardiovascular system, particularly in association with coronary arteries. In vivo and in vitro studies have demonstrated that calcitonin gene-related peptide possesses potent vasodilator properties. Circulating calcitonin gene-related peptide is derived primarily from ...

During NA-induced NST blood flow through BAT increased from 0.18 ml min-1 to 3.21 ml min-1 in 23 degrees C acclimated (equals thermoneutrality) and from 0.61 ml min-1 to 9.67 ml min-1 in outdoors (-2 to 12 degrees C Ta) acclimated Djungarian hamsters. In 23 degrees C acclimated hamsters this ...

The efficacy of systemic hypothermia in combination with cardiopulmonary bypass for the repair of congenital cardiac malformations is established. Surface cooling in infants with ventricular septal defects as a prebypass adjunct has been associated with visceral ischemic complications. Surface cooling in infant pigs with ventricular septal defects results in increased ...

This study examined the hemodynamic and regional vascular profile of intravenous (i.v.) milrinone during increasing doses (3, 6, 12 micrograms/kg/min, n = 8) and by intraindividual comparison of milrinone and dobutamine (n = 10) in normal conscious rats. At 3 micrograms/kg/min, Milrinone increased coronary and cerebral blood flow (radioactive microspheres ...

The effects of three hypotensive agents, sodium nitroprusside (SNP), nitroglycerin (NTG), and adenosine triphosphate (ATP), on blood flow distribution and vascular capacitance were examined in dogs anesthetized with sodium pentobarbital. To eliminate the modification by the baroreflex, carotid sinus was denervated and aortic and cardiopulmonary vagal fibers were sectioned. Total ...

The onset of right ventricular diastolic collapse has been shown to be a very sensitive and specific sign of cardiac tamponade in both clinical and conscious canine studies, and is associated with a decline in cardiac output of about 20%. To determine if blood flow to critical regions was affected ...

Cardiac output and its distribution were measured using the microsphere technique before and at 2 and 6 h during the infusion of ritodrine, 1.5 microgram X min-1 X kg-1 i.v., into near-term pregnant guinea pigs. Average cardiac output increased 16 and 25%, and total peripheral resistance decreased 16 and 19% ...

A perfused brain preparation was developed utilizing non-pulsatile flow of artificial blood. Cortical electrical activity and respiratory motor output were maintained for as long as 7-8 h. This preparation permits stable intracellular recordings from CNS neurons displaying ongoing respiratory activity, and should permit analysis of synaptic and intrinsic cellular mechanisms ...

The effects of fentanyl or cardiovascular function, regional distribution of cardiac output, and the dose required for producing anesthesia were studied in ten previously catheterized, newborn lambs. In addition, the effects of fentanyl on cerebral blood flow and oxygen utilization were examined. Fentanyl in cumulative doses as high as 4.4 ...

I have examined the systemic and regional hemodynamic effects of an intravenous arginine vasopressin (AVP) infusion at a rate of 220 pg X kg-1 X min-1 maintained for 48 h in 12 conscious dogs. Plasma AVP concentration increased from 2.8 +/- 1.1 to 8.2 +/- 1.4 pg/ml, and plasma osmolality ...