Search Results
Results 601 - 650 of 1562
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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 ...
Ingemansson R - - 1997
BACKGROUND: The aim of this study was to investigate how much perfusion pressure an artery can tolerate without significant loss of endothelium-dependent relaxation (EDR) and vascular contractility. METHODS: The abdominal aortas of 396 Sprague-Dawley rats were used. One hundred twenty aortas were flush-perfused for 1 or 5 minutes with cold ...
Seely S - - 1997
When the heart contracts, it compresses its own arteries, so that it cannot supply itself with blood during systole. Its perfusion is effected during diastole by an auxiliary pump, which is an elastic reservoir consisting of the aorta and its large branch arteries. During systole this container is distended, storing ...
Rasiah R L - - 1997
We describe a method for multiple indicator dilution studies in the isolated perfused human placental lobule developed to investigate the relationships between changes in pressure and flow and solute clearance. A peripheral lobule of a human placenta is perfused with a tissue culture-based medium and the perfusate oxygen tension, arterial ...
Moravec C S - - 1997
We tested the hypothesis that in the intact heart, mitochondrial metabolism is activated by mitochondrial Ca2+ uptake during increased work. We measured left ventricular pressure (LVP), pyruvate dehydrogenase (PDH) activity, and mitochondrial and A band elemental content by electron probe microanalysis (EPMA) in Langendorff-perfused hamster hearts under control conditions, after ...
Harrison J M - - 1997
The electroretinogram (ERG) vs perfusion pressure relation was studied in anesthetized rabbits during mechanically induced changes in mean arterial pressure (MAP). After 1 hr of dark adaptation, ERGs were obtained at perfusion pressures from 10 to 95 mmHg with each pressure held for 30-60 sec, and at three levels from ...
Gual A - - 1997
PURPOSE: To analyze the influence of time of storage, the presence of albumin at physiological concentrations, and the perfusion with anisosmotic media on the aqueous humor outflow facility (C) of isolated bovine anterior segments (AS). METHODS: Anterior segments dissected from cow eyes were perfused at a constant pressure of 10 ...
Gralinski M R - - 1997
Evidence is presented that treatment with a highly sulfated low-molecular-weight heparin fraction, LU 51198, protects the ex vivo perfused rabbit heart from human complement-mediated injury. Hearts from male New Zealand White rabbits were perfused under constant flow in the Langendorff mode. After equilibration, normal human plasma was added to the ...
Fujimiya M - - 1997
Since definitive morphological studies showing the luminal release of serotonin have not been reported, we used a perfused system which allows physiological monitoring and biochemical as well as morphological evidence indicating release of serotonin from enterochromaffin cells. Isolated vascularly and luminally perfused rat duodenums exposed to 5-35 cmH2O of luminal ...
Crandall C G - - 1997
During a hyperthermic challenge, skin blood flow (SkBF) increases primarily through activation of the cutaneous active vasodilator system. However, mechanisms through which activation of this system elevates SkBF remain unknown. In this project, we sought to identify whether functional beta-adrenoceptors exist on cutaneous vessels and, if present, whether these receptors ...
Forster B A - - 1997
Uptake of circulating albumin by the aortic wall is greater downstream than upstream of branches in immature rabbits, but the opposite pattern occurs in mature animals. We investigated the role of NO in determining these variations. Descending thoracic aortas of rabbits were cannulated using techniques that avoid depressurization, overstretching, and ...
Tao Z W - - 1997
AIM: To study the cardioprotective effects of oxygen free radicals (OFR) and calcitonin gene-related peptide (OGRP) pretreatment on myocardial damages due to OFR in isolated perfused rat heart. METHODS: The hearts were perfused in a Langendorff mode. OFR were generated by electrolysis of Krebs-Henseleit (K-H) solution. RESULTS: OFR pretreatment reduced ...
Cvetković N - - 1997
In this paper we describe a modified intestinal perfusion technique for investigation of bioadhesion phenomena. This technique is an in vitro method with well standardized experimental conditions which measures the intestinal intraluminal pressure and its oscillation. This also allows the vitality of the intestinal segment used in the experimental to ...
Champion H C - - 1997
Responses to rat (r) adrenomedullin (ADM) and human (h) ADM were compared in the hindlimb vascular bed of the cat under conditions of controlled blood flow. Intra-arterial injections of rADM and hADM in doses of 0.03-1 nmol caused dose-related decreases in hindlimb perfusion pressure. In terms of relative vasodilator activity, ...
Aiuto L T - - 1997
OBJECTIVE: To investigate whether an infusion of recombinant tissue plasminogen activator would dissolve microvascular thromboses and improve organ perfusion in a patient with fulminant meningococcemia. DESIGN: Descriptive case report. SETTING: Fifteen-bed pediatric intensive care unit (ICU) in a university hospital. PATIENT: A 4-month-old male with fulminant meningococcemia, refractory shock, and ...
Todaka K - - 1997
OBJECTIVES: The impact of acute collagen disruption by the disulfide donor, 5,5'-dithio-2-nitrobenzoic acid (DTNB) on ventricular properties was tested in rat hearts. METHODS: Collagen was degraded acutely in 13 isolated, isovolumically contracting rat hearts by perfusion with 1 mM DTNB added to Krebs-Henseleit solution for 1 hour followed by 2-hour ...
Wilson P S - - 1997
Vascular shear stress increases when blood flow or blood viscosity increases or when vessel diameter decreases. In the systemic circulation, shear stress is a potent stimulus for endothelial nitric oxide synthesis. We studied isolated rat lungs to determine whether increasing shear stress increases nitric oxide synthesis in the pulmonary circulation. ...
Rao V - - 1997
BACKGROUND: Improved methods of donor heart preservation may allow for prolonged storage and permit remote procurement. Previous attempts to use oxygenated perfusion circuits during storage have not gained widespread acceptance because they were either too impractical or complicated to use for remote harvest. We hypothesized that collection and perfusion of ...
Heslinga J W - - 1997
If intramyocardial pressure (IMP) is the pressure that causes coronary flow to stop, i.e., "backpressure," then it should be equal to the zero-flow perfusion pressure intercept (Pzf). Therefore we determined Pzf and IMP at zero flow (IMPzf) in papillary muscles suspended isometrically in a bath, superfused with a well-oxygenated Tyrode ...
Cringle S J - - 1997
PURPOSE: A perfusion system for studying the vasoactive properties of the guinea-pig choroid is described. METHODS: The principle of operation is that the vascular resistance of the entire vascular network of an isolated, perfused eye can be monitored by recording the pressure required to deliver a constant flow of perfusate ...
Inserte J - - 1997
To investigate the role of Na(+)-H+ exchange occurring during hypoxia in the genesis of reoxygenation-induced myocardial oedema, isolated perfused rat hearts were submitted to 40 min of hypoxia and 90 min of reoxygenation. The influence of three factors on myocardial water content was analysed according to a 2 x 2 ...
Falck G - - 1997
RATIONALE AND OBJECTIVES: The purpose of this study was to evaluate the role of biophysical factors (viscosity, temperature, osmalality, perfusion pressure, and ionic washout) on cardiac contractility during coronary bolus perfusions. METHODS: Guinea pig hearts were perfused in the osmolality mode at constant and high flow (30 mL/min) and were ...
Osaki J - - 1997
OBJECTIVES: The aim was to determine whether proto-oncogene c-fos expression and acceleration of protein synthesis by acute pressure overload to the heart were coupled with a cAMP- and protein-kinase-A-dependent system in adult rat heart. METHODS: Isolated adult rat hearts were perfused as Langendorff preparations at a constant aortic pressure of ...
Cirino G - - 1997
1. Endothelin-1 (ET-1) production from endothelial cells is generally believed to be a process that happens over the course of hours. 2. When fluoroaluminate (AIF-4) was infused in the isolated perfused arterial and venous vessels of the rat mesentery there was an increase in perfusion pressure on both sides. 3. ...
Casellas D - - 1997
The spatial organization of autoregulatory responses (AR) was assessed in couples of afferent arterioles (AA), either grouped as anatomic pairs or branched sequentially along the same arcuate arterial branch (ArcB). With blood-perfused juxtamedullary nephron (JMN) preparations, AR were elicited by raising blood perfusion pressure from 60 to 120 mmHg and ...
Lopez B L - - 1997
BACKGROUND: Recent studies have determined that the product of NO and superoxide is peroxynitrite (ONOO-), an anion with deleterious tissue-oxidant effects. OBJECTIVE: To examine the effects of ONOO- on the isolated perfused rat heart. Sprague-Dawley rat hearts were perfused with a cell-free, Krebs-Henseleit solution on a Langendorf perfusion apparatus. The ...
Albes J M - - 1997
The optimal temperature of the pulmonary flush perfusate is still a matter of controversy. At present, a temperature of 10 degrees C is favored. This study deals with the structural and functional impact of different perfusate temperatures on lung preservation. In an extracorporeal rat heart-lung model lungs were preserved with ...
Champion H C - - 1997
The heptadecapeptide nociceptin, also known as Orphanin FQ, is a newly-discovered endogenous ligand for the opioid-like G-protein-coupled receptor ORL1. In the present study, in order to investigate the structure-activity relationship for nociceptin, responses to nociceptin, [Tyr1]-nociceptin, nociceptin-(2-17), nociceptin-(1-11), and nociceptin-(1-7) were compared in the hindquarters vascular bed of the rat. ...
Fraser R - - 1997
Disordered small intestinal motility occurs frequently during acute radiation enteritis. However, the characteristics and time course of the motor dysfunction are poorly defined. These parameters were assessed in a novel animal model of radiation enteritis. Ileal pressures were recorded in vitro with perfused micromanometric catheter using an arterially perfused ileal ...
Blech M - - 1997
Twelve surgically removed human kidneys (mainly tumor kidneys) were investigated. The investigations comprised perfusion criteria (perfusion flow, perfusion pressure, perfusion resistance, electrolyte equilibration). During perfusion of the kidneys with HTK solution, the perfusion resistance was nearly three times as high in human kidneys as in canine kidneys perfused under the ...
Czapla M A - - 1997
The heptadecapeptide nociceptin, also known as Orphanin FQ, is a newly discovered endogenous ligand for the G-protein coupled, opioid-like receptor ORL1. In the present study, responses to intra-arterial injections of nociceptin were investigated in the hindquarters vascular bed of the rat. Under constant-flow conditions nociceptin induced dose-dependent decreases in hindquarters ...
Nagakawa T - - 1997
BACKGROUND/AIMS: Variable-load cholangiomanometry was performed to obtain data on terminal biliary function during the surgical treatment of cholelithiasis. The decision of whether or not to perform a definitive biliary drainage procedure was based on the results of this test. MATERIAL AND METHODS: The rate of perfusion was reduced in four ...
Gilabert R - - 1997
The aim of this study was to investigate the influence of substances that increase intracellular cAMP levels on the aqueous humor outflow facility (C) of isolated bovine anterior segments. Anterior segments were perfused in vitro at a constant pressure of 10 mmHg for 270 min with a general protocol as ...
Czapla M A - - 1997
Nociceptin, the endogenous ligand for the ORL1 receptor, has been shown to decrease systemic arterial and hindquarters perfusion pressures in the rat. The present study was undertaken to determine if decreases in systemic arterial and hindquarters perfusion pressures, in response to nociceptin, are mediated by a naloxone-sensitive mechanism. Injections of ...
Champion H C - - 1996
Responses to pituitary adenylate cyclase polypeptide (PACAP)-27, PACAP-38, and vasoactive intestinal peptide (VIP) were compared in the peripheral and pulmonary vascular beds of the cat and in the isolated perfused neonatal pig heart. Intravenous injections of PACAP-27 and PACAP-38 produced biphasic changes in systemic arterial pressure whereas iv injections of ...
Mangiarua E I - - 1996
The molecular mechanisms responsible for the vascular hypertrophy observed in the arteries of hypertensive subjects are poorly understood. In this study, we tested the hypothesis that an increase in intraluminal pressure could by itself induce some of the vascular changes associated with hypertension, such as increased DNA synthesis and c-fos ...
Luksch H - - 1996
In the present study an isolated preparation of the complete anuran central nervous system (CNS) is described which can be kept alive for several days and allows tracing, immunohistochemical and electrophysiological studies. A simple perfusion chamber is being used in which the isolated CNS preparation is superfused with oxygenated Ringer. ...
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