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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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, ...

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 ...

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 ...

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. ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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. ...

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 ...

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 ...

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 ...

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. ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

We described here an original device for laser Doppler (LD) flowmetry measurements of gastric mucosal perfusion, which was used here in healthy volunteers. A modified nasogastric tube containing the LD probe was inserted. Aspiration via a catheter, fixed in parallel to the probe, held the probe against the gastric wall. ...

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 ...

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. ...

The effects of cholinergic agonist and nitrovasodilator on transorgan pressure-flow relationships were characterized under antegrade aortic perfusion of the rat heart. Under basal conditions, the preparation exhibited a stable linear dependence of perfusion pressure upon regulated transorgan flow rate from 0 to 9 ml/min with a transorgan vascular resistance of ...

BACKGROUND: The maximum degree of microvascular distribution of cardioplegic solution is considered important to achieve optimum myocardial protection. This study attempts to demonstrate that the addition of retrograde cardioplegia to antegrade cardioplegia improves overall microvascular perfusion. METHODS: Explanted human hearts (n = 6) were treated with cold cardioplegic arrest and ...

This study was conducted to examine the hypothesis that P2 purinoceptors contribute to pressure-induced autoregulatory adjustments of afferent arteriolar caliber. Experiments were performed in vitro using the blood-perfused juxtamedullary nephron technique. Afferent arteriolar diameter averaged 19.2 +/- 0.6 microns (n = 51) at control perfusion pressure of 100 mmHg and ...

In most theoretical analyses of the heart, the tissue has been assumed to be incompressible. Because the myocardium is extensively perfused with distensible vessels, increasing the stiffness of the surrounding tissue, as with contraction or passive stretching, should decrease the volume of fluid in these vessels. Using a digital subtraction ...

We investigated the intra-operative application of intraperitoneal perfusion of hyperthermic chemotherapy and its effects on cardiovascular status and oxygen consumption and delivery in 11 patients following laparotomy for surgical resection of recurrent tumours or peritoneal metastases. Closed peritoneal irrigation was carried out with perfusate at a temperature of 45-47 degrees ...

BACKGROUND: There are several shortcomings in current understanding of how the microvasculature maintains tissue homeostasis. Presently unresolved issues include (1) integration of the potentially conflicting needs for capillary perfusion and hydrostatic pressure regulation, (2) an understanding of signal transmission pathways for conveying information about tissue energetic status from undersupplied tissue ...

The arrhythmogenic actions of endothelin peptides were studied in isolated perfused hearts from guinea pigs and rats. Digoxin-induced ectopic ventricular complexes were partially antagonized by phosphoramidon, an endothelin-converting enzyme inhibitor. On the contrary, these rhythm disturbances were potentiated by big endothelin-1 in isolated perfused whole hearts from guinea pigs. Endothelin-1, ...

OBJECTIVE: The purpose of this study was to find predictive criteria for response to clozapine. METHOD: Single photon emission computed tomography studies of cerebral perfusion were done in 24 treatment-resistant schizophrenic patients while they were taking typical neuroleptics and again after they had been treated with clozapine for 6 months. ...

The cytochrome P-450 pathway is capable of metabolizing arachidonic acid to omega- and subterminal hydroxylase metabolites, 16-, 17-, 18-, 19-, and 20-hydroxyeicosatetraenoic acids (P-450 HETEs). We have quantitated, by gas chromatography-mass spectrometry (GC/MS), endogenous HETEs exiting the rabbit isolated perfused kidney elicited by hormonal stimulation. Kidneys were perfused with Krebs-Henseleit ...

Evidence is presented that treatment with a selective inhibitor of the alternative complement pathway, sCR1[desLHR-A], protects the ex vivo perfused rabbit heart from human complement-mediated injury. Hearts from male New Zealand white rabbits were perfused in the Langendorff mode. After equilibration, normal human plasma was added to the perfusate as ...

Hyperthermic isolated limb perfusion (ILP) with melphalan is an accepted method of treatment for advanced or recurrent melanoma on a limb. In a review of 124 patients who underwent 130 ILPs at the Sydney Melanoma Unit, the anaesthetic considerations are summarized. All patients received general anaesthesia. The level of monitoring ...