Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Extracorporeal perfusion of isolated sheep lungs with blood after 30 min of ischemia caused injury manifested by polymorphonuclear (PMN) leukocyte sequestration, pulmonary hypertension, thromboxane release, and increased pulmonary vascular permeability. To determine the roles of ischemia, extracorporeal perfusion, and oxygen in this injury, lungs ventilated with 28% O2-5% CO2 and subjected to 30 min of ischemia followed by 180 min of perfusion (ischemic-perfused, n = 23) were compared with lungs subjected to (1) ischemia without perfusion (ischemic, n = 7), (2) perfusion without ischemia (perfused, n = 20), or (3) both ischemia and perfusion during ventilation with 95% N2 (anoxic ischemic-perfused, n = 15). Compared with ischemic-perfused lungs, ischemic lungs had an increased reflection coefficient for albumin (sigma alb, 0.82 +/- 0.03 versus 0.54 +/- 0.05) and decreased filtration coefficient (Kf, 0.05 +/- 0.01 versus 0.11 +/- 0.03 g.min-1.mm Hg-1.100 g-1). Perfused lungs had increased pulmonary hypertension, lung PMN leukocytes, and sigma alb (0.74 +/- 0.05); Kf was not different. Anoxic ischemic-perfused lungs had decreased pulmonary hypertension and thromboxane release, but sigma alb and Kf were not altered. These results suggest that extracorporeal perfusion caused PMN leukocyte sequestration, thromboxane release, and pulmonary hypertension, whereas ischemia caused derecruitment of vascular surface area. Injury required both ischemia and perfusion, but it was not decreased by anoxia, suggesting that oxygen radicals were not involved.
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PMID:Vascular injury in isolated sheep lungs. Role of ischemia, extracorporeal perfusion, and oxygen. 854 16

A 38-year-old patient underwent left single-lung transplantation for end-stage histiocytosis with secondary pulmonary hypertension and polycythemia. Despite use of an optimal lung graft and a total ischemia limited to 250 minutes, major pulmonary edema developed postoperatively. Hemodilution resulted in a quick recovery of lung function. We speculate that blood hyperviscosity was a major factor of pulmonary edema in this patient.
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PMID:Hemodilution is an effective treatment for reperfusion edema after lung transplantation. 861 Feb 92

Orthotopic liver transplantation is an established therapy for end-stage liver disease. This study evaluated the range of cardiovascular abnormalities in patients undergoing evaluation for orthotopic liver transplantation and determined the prognostic implications of abnormal echocardiographic features, including ischemia during dobutamine stress echocardiography, in predicting postoperative cardiac events. Two-dimensional echocardiography was performed in 190 patients for assessment of left ventricular function, valvular pathology, and pulmonary hypertension. Dobutamine stress echocardiography was performed in 165 patients for evaluation of inducible ischemia. Contrast echocardiography for detection of intrapulmonary shunting was performed in 125 patients at rest and in 99 during dobutamine stress. Left ventricular dysfunction, significant valvular regurgitation, and inducible ischemia were identified in <1O% of patients. Pulmonary hypertension, left ventricular hypertrophy and > or = moderate intrapulmonary shunting were present in 12%, 16%, and 26% of patients, respectively. Severe intrapulmonary shunting predicted death prior to transplantation (P=0.01). Of the 71 transplanted patients, major perioperative events included global left ventricular dysfunction in four patients and myocardial infarction in one patient with normal coronary arteries. No preoperative echocardiographic parameters, including ischemia on dobutamine echocardiography, predicted these perioperative events. No cardiac events related to obstructive coronary artery disease occurred in the 154 patients without ischemia on dobutamine stress echocardiography. The majority of patients with end-stage liver disease, including those with alcoholic cirrhosis, have normal cardiac function on two-dimensional echocardiography. Severe intrapulmonary shunting portends a poor prognosis in patients awaiting transplantation. A negative dobutamine stress echocardiogram appears useful in excluding patients at risk for perioperative cardiac events related to obstructive coronary artery disease.
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PMID:Two-dimensional and dobutamine stress echocardiography in the preoperative assessment of patients with end-stage liver disease prior to orthotopic liver transplantation. 861 Apr 15

Hepatic surgery in man often requires a transient interruption of the blood flow to the liver. After the vascular declamping the hepatic reperfusion induces a group of phenomena commonly called "reperfusion injuries." The aim of this study was to evaluate the presence and effect of vasoactive agents that could induce the acute pulmonary arterial hypertension which contributes to reperfusion injury. Wistar rats were used. The hepatic ischemia was induced by crossclamping the whole hepatic hilus for 20, 40, and 60 min. In control experiments a sham operation was performed. Blood samples were collected from the suprahepatic inferior vena cava. Strips of the main pulmonary artery were set up in an isolated organ bath and tested for the response to noradrenaline, adrenaline, KCl, and plasma samples. Plasma levels of catecholamines were determined by high-performance liquid chromatography. Plasma concentration of noradrenaline significantly increased from 1.6 +/- 0.4 (control) to 10.8 +/- 2.9 ng.ml-1 and adrenaline concentration rose from 2.7 +/- 0.7 to 38.7 +/- 7.6 ng.ml-1 after ischemia. Noradrenaline potency, compared to control values, significantly increased after prolonged liver ischemia. The plasma samples collected after prolonged liver ischemia caused a greater contraction of the pulmonary artery than from control plasma. This contraction is partially inhibited by phentolamine. We conclude that hepatic ischemia modifies the response of the pulmonary artery to exogenous noradrenaline. At the same time it induces an increase in the plasma levels of adrenaline and noradrenaline. The resulting combined effect may cause the pulmonary hypertension which has been observed in reperfusion injury.
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PMID:Evaluation of the reperfusion syndrome after liver ischemia in the rat. 863 32

The chronic increase of pulmonary vascular resistance after lung transplantation is only partly due to an active increase in baseline vasomotor tone, but the nature of the acute pulmonary hypertension after ischemia and reperfusion is not known. We studied the effects of sodium nitroprusside on pulmonary hemodynamics during reperfusion in porcine left lung allotransplants. In twelve pigs (weight: 18 to 24 kg) pulmonary arteries of the native and the transplanted lung were cannulated for right-heart bypass. The total blood flow was 2 L/min. Flow distribution between the lungs was measured at equal mean pulmonary artery pressure, and pulmonary vascular resistance at equal and constant flow-i.e., 1 L/min to each lung. After baseline measurements sodium nitroprusside (1, 3, and 9 microg/kg/min) was administered to six animals (SNP group). The control group (n=6) received an equal amount of the vehicle. After 30 min of discontinuation of the drug infusion, the schedule was repeated. In the transplanted lung, pulmonary vascular resistance decreased in all animals during the first hour of reperfusion. During the second drug infusion pulmonary vascular resistance was significantly lower in the SNP group compared with the control group only at the highest infusion rate of the drug (9 microg/kg/min), which also induced a 44% decrease in systemic vascular resistance. Arterial oxygen tension remained comparable in the two groups throughout the study. Our data suggest that other factors besides active vasoconstriction may contribute to the acute increase of pulmonary vascular resistance after lung transplantation.
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PMID:Abnormal in vivo response to sodium nitroprusside after porcine single lung transplantation. 863 65

Single-lung transplantation has been abandoned for the treatment of pulmonary hypertension by many centers because of overperfusion of the graft following implantation. Euro-Collins solution is currently used for lung preservation despite the vasoconstrictive effect of this intracellular-type solution. We hypothesized that high-flow reperfusion, alone or in combination with Euro-Collins-induced vasoconstriction, may cause lung dysfunction. Twenty-eight New Zealand White rabbit lungs were harvested and studied in an isolated, blood-perfused model of lung function after 4 hours of cold ischemia. Control lungs were preserved with 50 ml/kg cold saline solution flush and reperfused at either normal flow (60 ml/min) or high flow (120 ml/min). Experimental lungs were preserved with 50 ml/kg cold Euro-Collins solution and reperfused at normal or high flow rates. The arteriovenous oxygen gradient at the end of the 30-minute reperfusion period was significantly lower in the high-flow versus the low-flow experimental group (31.1 +/- 4.2 vs 130.6 +/- 41.6 mm Hg, p < 0.05). The pulmonary vascular resistance was increased in the high-flow groups and the experimental groups, with a statistically significant difference between low-flow experimental and control groups (64374.4 +/- 5722.6 vs 37041.5 +/- 2110.9 dynes x sec x cm(-5), p < 0.001). The percentage decrease in dynamic airway compliance in the high-flow experimental group was markedly different from that in the high-flow control group (-51% +/- 13.3% vs -10.15% +/- 3.4%, p < 0.05). Similarly, the wet/dry ratio of the lungs in the high-flow experimental group (13.92 +/- 2.32) was significantly greater than that in the low-flow experimental group (6.27 +/- 0.19, p < 0.01) and than that in the high-flow control group (5.88 +/- 0.23, p < 0.001). These data demonstrate that high-flow reperfusion and preservation with Euro-Collins solution are deleterious to lung function, both individually and in combination, in an ex vivo rabbit lung model. Lung preservation with Euro-Collins solution may not be optimal when high-flow reperfusion is anticipated, as in the setting of unilateral lung transplantation for pulmonary hypertension.
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PMID:Euro-Collins solution exacerbates lung injury in the setting of high-flow reperfusion. 869 54

The authors describe a rare case of pulmonary thromboembolism with unusual clinical findings and emphasized the large difficulty encountered in formuling a correct diagnosis in a reasonable time. A man, 60 years old, was admitted to a Medical Division of our hospital for the appearance of chest pain and epigastric pain during effort in the last year. He smoked 20 cigarettes a day and drank wine (1 or 2 litres a day). He was affected by hypercholesterolemia and in the past reported relapsed thrombophlebitis in the left leg. Four years before admission to our hospital he underwent large and small left saphenectomy. He had no cardiac events in the past. After a non significant exercise stress test the patient was treated with nitrates and asa and was discharged from the hospital. At home the symptoms increased and after 8 months the patient was admitted again to the Cardiologic Division of the hospital. At admission he reported dyspnea and chest pain at rest, not only during effort and the ECG showed negative T waves in anterior and inferior leads. Intravenous heparine, nitrates and calcium antagonists stabilized the clinical picture. The following examinations revealed: reduction of the T wave negativity at the ECG registered during chest pain; mild enlargement of the heart at the chest roentgenogram; normal value of the left ventricle and apical and midseptal by ipokinesia at the transthoracic echocardiogram; normal coronary artery at the coronary arteriography. "Vasospastic angina" was diagnosed and the patient was discharged after 20 days, asymptomatic. After 15 days he returned to the hospital again for chest pain, dyspnea, hypotension and syncope despite therapy. At physical examination he showed a painful left tibio-tarsal tumefaction, an increased and splitting second heart sound in the pulmonary area and a systolic murmur in the third and fourth left interspace. The ECG showed a severe anterior ischemia, while a new transthoracic echocardiogram revealed a considerable dilatation of the right atrium, right ventricle and the main pulmonary artery with severe tricuspid regurgitation and pulmonary hypertension (mean PAP about 50 mmHg). The following pulmonary perfusion scintigraphy confirmed the diagnosis of pulmonary embolism and the selective right and left pulmonary arteriography exhibited multiple thrombi and large intravascular filling defects. The right heart catheterization confirmed a chronic precapillary pulmonary hypertension (mean PAP = 55 mmHg). About 24 hours after these examinations the patient died because of a cardiac arrest with electromechanical dissociation. Pulmonary thromboembolism is a potentially fatal disease characterized by a largely variable clinical presentation. Frequently pulmonary embolism diagnosis is difficult especially when clinical findings are unusual. In the case observed the "typical" chest and epigastric pains associated with the electrocardiographic findings directed diagnosis towards myocardial ischemia. Also after the coronary arteriography that showed normal coronary artery, the erroneous diagnosis persisted. Pulmonary embolism was correctly diagnosed too late to begin an effective therapy. These unusual clinical findings and diagnostic mistakes are stressed and critically reviewed in the article.
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PMID:[Pulmonary thromboembolism. A clinical case with unusual presentation]. 871 Jan 39

Endothelin-1 is a recently discovered peptide mainly released from endothelial cells. Hypoxia and ischemia as well as numerous factors such as angiotensin 11, thrombin and transforming growth factor beta 1 stimulate the formation of the peptide. On the other hand the synthesis of endothelin is inhibited by nitric oxide and atrial natriuretic peptide via the formation of cyclic guanosine monophosphate. Released from endothelial cells endothelin-1 mediates transient vasodilation followed by a profound and longlasting vasoconstriction. Endothelin is also a mitogen for smooth muscle proliferation. Endothelins exert their biological effects via activation of specific receptors. Two different receptors have been cloned from mammalian tissues (ET(A) and ET(B) receptors). On vascular smooth muscle cells both receptors mediate contractions. Endothelial cells only express ET(B) receptors linked to the formation of nitric oxide and/or prostacyclin formation. Increased plasma concentrations of endothelin-1 have been described in a variety of diseases such as pulmonary hypertension, arteriosclerosis, renal failure, acute coronary syndromes, heart failure, migraine and vascular diseases. Recently an increasing number of endothelin receptor antagonists have been synthetized, which have been shown to inhibit endothelin-mediated vasoconstriction. Clinical studies are now ongoing to elucidate the pathophysiologic role of endothelin and the potential benefit of the blockade of the system in different disease states.
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PMID:Endothelin and endothelin antagonists: potential role in cardiovascular and renal disease. 873 56

In summary, newer imaging technologies yield three-dimensional pictures of the left ventricle. Detailed information is provided on regional wall motion, wall thickening, and ventricular volumes, which can be helpful in managing patients with cardiac disease. MR imaging gives the highest resolution images, and MR angiography can be invaluable in assessing the anatomy of an aortic dissection. Gated tomography with a technetium-based myocardial perfusion tracer can be thought of as a low-resolution cine MR imaging study. Combined function and perfusion nuclear studies performed at rest in an ICU can give information on myocardial perfusion and stunning, which is helpful in managing patients with acute ischemic syndromes. First pass RNA is probably the most accurate method for measuring RVEF and can be performed at the bedside using a portable multicrystal camera. Serial measurements of RVEF may be helpful in managing patients with pulmonary hypertension of various causes. For patients with documented acute myocardial infarction or chest pain and no acute myocardial necrosis or for patients undergoing preoperative risk assessment, combined perfusion and function using nuclear techniques yields both stress-induced ischemia and resting ventricular function in a single procedure and is timely and cost effective.
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PMID:New imaging techniques for assessing cardiac function. 890 77

To present an overview of the surgical issues in lung transplantation, including the historical context and the rationale for choosing a particular procedure for a specific patient, we reviewed and summarized the current medical literature and our personal experience. Several surgical options are available, including single lung transplantation; double lung transplantation; heart-lung transplantation; bilateral, sequential single lung transplantation; and (recently) single lobe transplantation. Although single lung transplantation is preferred for maximal use of the available organs, bilateral lung transplantation is necessary for septic lung diseases and may be appropriate for pulmonary hypertension and bullous emphysema. Heart-lung transplantation is performed for Eisenmenger's syndrome and for primary pulmonary hypertension with severe right ventricular failure. General factors for consideration in assessment of compatibility of the donor and potential recipient include ABO blood group, height (the donor should be within +/- 20% of the recipient's height), and length of the lungs (determined on an anteroposterior chest roentgenogram). Graft preservation and minimal duration of ischemia are important. Complications associated with airway healing are related to ischemia of the donor bronchus. We have addressed the issue of donor bronchial ischemia by direct revascularization of the donor bronchial arteries with use of the recipient's internal thoracic artery. Currently, lung transplantation offers a realistic therapeutic option to patients with end-stage pulmonary parenchymal or vascular disease.
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PMID:Surgical issues in lung transplantation: options, donor selection, graft preservation, and airway healing. 900 92


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