Search Results
Results 601 - 650 of 1598
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Edmunds N J - - 1999
1. The cardiac depressant actions of TNF were investigated in the isolated perfused rat heart under constant flow (10 ml min(-1)) and constant pressure (70 mmHg) conditions, using a recirculating (50 ml) mode of perfusion. 2. Under constant flow conditions TNF (20 ng ml(-1)) caused an early (< 25 min) ...
Traynor T - - 1998
The effect of the adenosine type 1 receptor agonist N6-cyclohexyladenosine (CHA) on glomerular vascular reactivity was studied in male angiotensin II type 1A (AT1A) receptor knockout mice (9). Vascular reactivity was assessed as the response of stop-flow pressure (PSF) to infusion of CHA into loops of Henle using micropuncture techniques. ...
Wu J - - 1998
INTRODUCTION: Cytochalasin D in tissue bath superfusate inhibits the contraction of isolated thin trabeculae from canine right ventricle without affecting the intracellular action potential recorded with glass microelectrode. The purpose of this study was to test whether cytochalasin D could also be used to immobilize perfused wedges of ventricular muscle ...
Cheng Y - - 1998
Voltage-sensitive dyes and imaging techniques have proved to be indispensable tools for use in in vitro electrophysiological studies. To avoid motion artifacts in optical recordings, electromechanical uncouplers such as 2,3-butanedione monoxime (BDM) are required. In this study, we sought to determine whether the voltage-sensitive dye RH421 had an effect on ...
Hoover D B - - 1998
Goals of this study were to identify and characterize effects of neurokinin A (NKA) in isolated guinea pig hearts. Bradycardia, augmentation of ventricular contractions, and reduction of perfusion pressure were prominent responses to bolus injections of NKA (0. 25-25 nmol). NKA was more potent than substance P (SP) in causing ...
Altemeier W A - - 1998
To explore mechanisms of hypoxemia after acute pulmonary embolism, we measured regional pulmonary blood flow and alveolar ventilation before and after embolization with 780-micrometers beads in five anesthetized, mechanically ventilated pigs. Regional ventilation and perfusion were determined in approximately 2.0-cm3 lung volumes by using 1-micrometers-diameter aerosolized and 15-micrometers-diameter injected fluorescent ...
Noble B J - - 1998
1. In chloralose-anaesthetized, artificially ventilated dogs, the splenic pedicle was tied and the carotid sinuses were vascularly isolated and perfused at controlled pressures. In Series 1 experiments, the hepatosplanchnic circulation was perfused through the abdominal aorta with a tie on the aorta separating it from the caudal circulation, which was ...
Gök S - - 1998
The effect of a leukotriene D4 (LTD4) receptor antagonist, L-648,051, was investigated in digoxin-induced cardiac toxicity in isolated guinea-pig hearts (Langendorff preparation). Digoxin infusion (25 microg.ml-1, 0.5 ml.min-1) increased perfusion pressure and contractile force initially, but decreased them later. The onset of first ventricular premature beats (VPBs) matched the increase ...
de Curtis M - - 1998
We describe a new method for studying the interactions between vascular tone changes and neuronal activity in the arterially perfused isolated brain of the adult guinea pig maintained in vitro. Electrophysiological recordings were performed in the piriform and entorhinal cortices with the entire arterial bed preserved or after vascular restriction ...
Kunst P W - - 1998
Electrical impedance tomography (EIT) is a technique that makes it possible to measure ventilation and pulmonary perfusion in a volume that approximates to a 2D plane. The possibility of using EIT for measuring the left-right division of ventilation and perfusion was compared with that of radionuclide imaging. Following routine ventilation ...
Sielenkämper A W - - 1998
Interruption of patent ductus arteriosus (PDA) using video-assisted thoracoscopic surgery (VATS) has recently been introduced into clinical practice. To study cardiovascular and pulmonary function during VATS, we treated 16 newborn pigs (weight 1421+/-44 g) with PDA with conventional surgical interruption (CSI; n = 7) or interruption via VATS (n = ...
Nowicki P T - - 1998
Studies were conducted to determine the effect of mechanically induced sustained flow reduction on intestinal hemodynamics and oxygenation in 3- and 35-day-old swine. In vitro gut loops were perfused under controlled-pressure conditions from an oxygenated blood reservoir at age-appropriate perfusion pressures; pressure was rapidly reduced to a level that lowered ...
Wen J G - - 1998
PURPOSE: To create an animal model with mild and severe partial unilateral ureter obstruction in young rats using a modified Ulm and Miller technique and to characterize the model by acute renal pelvic pressure measurements. MATERIAL AND METHODS: During anesthesia the upper fourth (n = 15) or the upper two-thirds ...
Okazaki K - - 1998
1. We examined the vasodilatory effect of hypercapnia in the rat isolated mesenteric vascular bed. The preparation was perfused constantly (5 ml min(-1) with oxygenated Krebs-Ringer solution, and the perfusion pressure was measured. In order to keep the extracellular pH (pHe) constant (around 7.35) against a change in CO2, adequate ...
Newman J M - - 1998
Angiotensin (AII) and serotonin (5-HT) are both vasoconstrictors of the constant-flow perfused rat hind limb that have opposite effects on thermogenesis, possibly the result of differing effects on vascular flow distribution between nutritive and non-nutritive pathways. In the present study interaction between the two opposing agents was examined with the ...
Osaki J - - 1998
BACKGROUND: Production of heat shock protein 70 (HSP70) in the heart is induced by hemodynamic stress, but its intracellular signal transduction system has not been elucidated well. OBJECTIVE: To investigate the hypothesis that protein kinase A (PKA)-dependent and protein kinase C (PKC)dependent systems are involved in the pressure-induced expression of ...
Lohman R - - 1998
Cardiac output (CO) is redistributed during hypovolemia, but it has not been clearly documented how this influences flap perfusion. Simultaneous changes in perfusion of a muscle flap and CO as modulated by reductions in cardiac filling pressure were compared in a pig model. The hypothesis was that flap flow (FF) ...
Cannan C R - - 1998
The perfusion sleeve (PS) is an "over-the-balloon" catheter designed to add perfusion capability to standard PTCA catheters. To evaluate the clinical effectiveness of this device, eight patients underwent standard PTCA with the PS retracted in the guide (Inflation 1-Control) and after deployment of the PS (Inflation 3-Control). Between standard inflations ...
Fujita S - - 1998
OBJECTIVE: The aims were to validate the use of a direct reading NO electrode, to compare the effects of diverse acting drugs on altering coronary flow (CF) and NO release, and to examine the effects of altered perfusion pressure on flow-induced changes in NO concentration [NO] in the hemoglobin free ...
Chen W H - - 1998
Perfused micromanometric assemblies with an outer diameter of 2 mm or less have been developed for use in premature infants and small laboratory animals. Such assemblies offer advantages with regard to subject comfort and low perfusion rates that make them attractive for use in adults. The aim of this study ...
Alexander B - - 1998
It is unclear how the omission of a perfusate oxygen carrier may influence data derived from prolonged in vitro liver perfusions. The effects of reduced perfusate oxygen content upon liver function tests conducted in livers from male Sprague-Dawley rats perfused for 6 h, were studied using diluted rat blood (PCV ...
Mc Parland B E - - 1998
In vivo agonist delivery to the lungs is characterized by absorption through the mucosal layer followed by access to the smooth muscle. When agonists are applied to perfused bronchial segments, a difference in potency to agonists applied to the serosal (outside) or mucosal (inside) surface can be demonstrated. In order ...
Ay I - - 1998
1. In isolated perfused rat kidney, under a constant flow of 8-10 ml/min, mean basal perfusion pressure was found to be 82.57 +/- 8.96 mm Hg (n = 70). 2. After a bolus injection of 10 micrograms/0.1 ml phenylephrine (PE) which causes maximum vasopressor response, a 93.27 +/- 0.56 mm ...
Samsom M - - 1998
The development of solid-state catheters with miniature pressure transducers and portable dataloggers with a large memory capacity has allowed recording of gastrointestinal motility in ambulant subjects. Developments in silicone rubber extrusion technology made it possible to build a perfused manometric system, using a perfused manometric assembly requiring a low volume ...
Pintér A - - 1998
Vasoactive intestinal polypeptide (VIP) was either injected intravenously (300 pmol.kg-1) or perfused (1 nmol in 1 min) into the sinus node artery (SNA) in anesthetized dogs to study its effect on subsidiary atrial pacemakers. Isochronal maps were obtained from 128 unipolar electrograms recorded on the epicardial surface of both atria ...
Kleen M - - 1998
Hypervolaemic haemodilution makes myocardial perfusion more homogenous as reflected by reduced fractal dimension of regional myocardial perfusion. The clinically more commonly performed acute normovolaemic haemodilution, however, has not yet been studied in this respect. Hyperoxic ventilation with 100% oxygen is used in conjunction with haemodilution to compensate for low oxygen ...
Eze A R - - 1998
Intermittent lower extremity compression increases cutaneous blood flow. The source of this increased perfusion and, the influence of physical activity on stimulated foot skin perfusion has not been elucidated. The purpose of this study is to determine the arterial and venous contributions to augmented cutaneous blood flow during foot and ...
Lecour S - - 1998
The present study was designed to identify the free radicals generated during the electrolysis of the solution used to perfuse isolated rat heart Langendorff preparations. The high reactivity and very short half-life of oxygen free radicals make their detection and identification difficult. A diamagnetic organic molecule (spin trap) can be ...
Nagasawa S - - 1998
A simulation study was undertaken using a compartmental flow model of a large high-flow cerebral arteriovenous malformation to investigate the hemodynamic changes during obliteration procedures. Under certain autoregulatory conditions, marked hyperperfusion (92 ml/100 g/min) could be induced in association with increased wall stress of the arterioles. Narrowing of the autoregulatory ...
Achtert A D - - 1998
BACKGROUND: The purpose of this investigation was to determine the accuracy of the estimation of ejection fractions (EFs) and left ventricular volumes from a commercially available software package (Quantitative Gated SPECT [QGS]) as a function of different true EFs, count level in the acquisitions, severity and location of perfusion defects, ...
Thorén A - - 1998
Reduction of central blood volume elicits a peripheral vasoconstrictor reflex in various tissues including skin, skeletal muscle and the hepatomesenteric region. The aim of the present study was to investigate whether this reaction includes a decreased perfusion of the jejunal mucosa in man. Laser Doppler flowmetry (LDF) was used to ...
Kincaid E H - - 1998
Inadequate splanchnic perfusion, detected as a low gastric intramucosal pH (pHi), in the face of normal systemic perfusion predicts an increased risk for multiple organ failure after trauma. Although the exact etiology of this low pHi is unknown, angiotensin II is thought to be an important regulator of gut perfusion ...
Dean D A - - 1998
BACKGROUND: The relative merits of antegrade infusion and retrograde infusion of cardioplegic solution in terms of heart weight, myocardial water content, and ventricular diastolic properties are undefined. Accordingly, we compared antegrade and retrograde flow of hemodiluted blood in isolated, hypothermic porcine hearts. METHODS: After cardiectomy, 1 L of cold heparinized ...
Segel L D - - 1998
BACKGROUND: These experiments were designed to evaluate the viability of large hearts after preservation by use of procedures that have shown good results with small animal hearts. Efficacy of novel long-term preservation protocols should be documented with a large animal model before such procedures can be adopted for clinical use. ...
Dijkman M A - - 1998
The perfusion-induced increase in cardiac contractility (Gregg phenomenon) is especially found in heart preparations that lack adequate coronary autoregulation and thus protection of changes in capillary pressure. We determined in the isolated perfused papillary muscle of the rat whether cardiac muscle contractility is related to capillary perfusion. Oxygen availability of ...
Tufto I - - 1998
Studies of interrelationships between physiological parameters of tumours are sparse. The possibility that vascular density might be related to the rate of angiogenesis, the rate of perfusion and/or the development of necrosis was examined in the work reported here. Xenografted tumours of four human melanoma cell lines (A-07, D-12, R-18 ...
Hagihara A - - 1998
The present study was designed to combine the monophasic action potential (MAP) recording technique with a well-established canine isolated, blood-perfused ventricular septum preparation for examining, simultaneously, electrical and mechanical drug-induced changes. A MAP catheter was positioned onto the base of a papillary muscle for recording the local MAP, using a ...
Rankin J C - - 1998
We review the literature on the way the structure of icefish gills relates the physiology of these haemoglobin-less fishes. Vascular casting confirmed earlier reports that the only special feature of the gills is the large size of the blood vessels, especially the prominent and continuous marginal channels Isolated perfused gill ...
DeGrado T R - - 1998
The effects of specific activity of meta-[(131)I]iodobenzylguanidine (MIBG) were studied in uptake-2 blocked isolated perfused rat heart. [(131)I]MIBG was administered in the perfusate as an 8-min pulse, followed by an 80-min washout period. Kinetic analysis of the externally monitored time-activity curves gave estimates of uptake rate and multiexponential clearance. Uptake ...
Kornowski R - - 1998
BACKGROUND: The efficacy of thrombolytic therapy might be influenced by changes in the hemodynamic status. The aim of the study was to examine whether changes in perfusion pressure could affect the time to reflow in an in-vitro model. METHODS: The in-vitro flow system comprised flexible plastic tubes that enclosed a ...
Wangemann P - - 1998
We developed a new technique, the isolated in vitro perfused spiral modiolar artery, which allowed the continuous measurement of the vascular diameter and control of the intravascular pressure. An isolated section of the spiral modiolar artery from the gerbil was perfused on one end with a set of concentric pipettes ...
Peter F W - - 1998
Impaired capillary perfusion may result in flap failure. Platelet emboli, polymorphonuclear leukocytes (PMNs), and/or vasospasm have been identified as possible causes. This study investigates the role of PMNs in causing impaired capillary perfusion in a free flap model. PMN concentrations were depleted using antineutrophil serum. The cremaster muscles of 20 ...
Wainwright C L - - 1997
Previous studies in pigs have shown that the A1-adenosine receptor agonist, R-PIA, is a potent antifibrillatory agent during myocardial ischaemia and that this effect can be overriden by atrial pacing. However, reports of A1-adenosine receptor down-regulation following chronic exposure to A1-receptor agonists suggest that this may limit their use as ...
Byrne B M - - 1997
The role of nitric oxide in hypoxic fetoplacental vasoconstriction (HFPV) was investigated using dually perfused human placental cotyledons. Standard medium (Earle's salt solution with added dextran and L-arginine) was equilibrated with 95 per cent O2 and 5 per cent CO2 (maternal side) and 94 per cent N2 and 6 per ...
Janse M J - - 1997
The authors have conducted several experimental studies of the cellular electrophysiology of the atrioventricular (AV) node employing the Langendorff-blood perfused heart of both dogs and pigs. Two types of experiments are described: experiments showing that cells with electrophysiological characteristics of typical nodal cells can be found outside Koch's triangle; and ...
Martinussen H J - - 1997
In this study, the dynamic interrelationships between myocardial functional state and changes in the second messenger content in pressure-overloaded hypertrophied hearts were investigated. Forty-three rat hearts were used after partial clamping of the abdominal aorta. The isolated hearts were perfused with Krebs-Henseleit buffer and allocated to perfusion for 20 s ...
Park J L - - 1997
The cytoprotective action of reviparin-sodium (LU-47311: Clivarin), a low-molecular-weight heparin, was examined in an ex vivo model of complement-mediated myocardial injury. The effective concentration of reviparin was determined by using an in vitro rabbit erythrocyte-lysis assay using 4% normal human plasma. Reviparin (0.01-2.73 mg/ml) reduced erythrocyte lysis in a concentration-dependent ...
Hoeldtke N J - - 1997
OBJECTIVES: Our purpose was to determine the effects of acidosis and acidosis-hypoxia on fetoplacental perfusion pressure and its response to angiotensin II. STUDY DESIGN: Perfused cotyledons from 14 placentas were studied with either an acidotic fetal circuit perfusate (n = 7) or an acidotic-hypoxic fetal circuit perfusate (n = 7). ...
Watanabe T - - 1997
The single pass type (SP) of blood cardioplegia is commonly used in North America during open heart surgery. However the recirculation type (RC) of blood cardioplegia is still widely used in other areas including Japan. Infusion blood cardioplegia using the latter technique often decreases the perfusion pressure. To determine the ...
Shenkman Z - - 1997
BACKGROUND: Retrograde cerebral perfusion through the superior vena cava (SVC) has been proposed to protect the brain from ischaemic injury during profound hypothermic circulatory arrest (PHCA). Its contribution to cerebral protection is unclear. Furthermore, the addition of anaesthetic or vasodilating agents to the SVC perfusate to enhance brain protection, has ...
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