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)

Albino rat experiments were undertaken to examine the protective action of heparin and the specific features of secondary renal ischemic changes when the agent was administered in different doses during revascularization. Ischemia was induced by 90-min ligation of the renal vessels and the ureter. Heparin was found to have a dose-dependent capacity to prolong rats' survival after ischemia of a single kidney. There were qualitative distinctions of morphological changes in the heparin-treated kidneys as compared with those in the control.
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PMID:[Features of reoxygenation-induced damage to ischemic kidney during heparin administration]. 782 46

To overcome the hemorrhagic complications that may occur during extracorporeal circulatory support for post cardiotomy shock patients, a heparinized circuit was introduced into the percutaneous cardiopulmonary support system and decreased systemically administered heparin during bypass. Heparin coated percutaneous cardiopulmonary support with low dose systemic heparinization was instituted in 13 patients (6 men and 7 women, mean age 62.2 +/- 8.5 years) who experienced circulatory collapse after cardiac surgery. Of the 13 patients, 9 could not be weaned from cardiopulmonary bypass and 4 had circulatory collapse in the operating room or in the intensive care unit. The duration of support ranged from 1 to 66 hr (mean 27.4 +/- 26.7), and the flow rate ranged from 1 to 3 L/min (2.2 +/- 0.5). An activated coagulation time of about 150 sec was maintained with or without minimal systematically administered heparin. Of the patients cannulated, 77% (10 of 13) were successfully weaned from percutaneous cardiopulmonary support and 39% (5 to 13) were long-term survivors. The causes of death were sepsis in three, progressive heart failure in three, lower leg ischemia in one, and vital infection in one. From the results of clinical or post mortem examinations, there was no massive bleeding or evidence of thromboembolism in the major organs. From observations made within 12 hr of initiation of percutaneous cardiopulmonary support, there was no significant decrease in the number of platelets, but platelet count had significantly decreased 24 hr after initiation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Heparin coated percutaneous cardiopulmonary support for the treatment of circulatory collapse after cardiac surgery. 785 34

Mesenteric venous thrombosis is an infrequent but distinct form of intestinal ischemia. We report 2 cases of acute mesenteric venous thrombosis, treated successfully by carrying out intestinal resection and postoperative anti-coagulation (Heparin, Sintrom). Both patients were diagnosed in the operating room. Improvements in computed tomography may identify patients earlier in their clinical course, heparin has both a primary therapeutic role in early disease and a postoperative adjunctive role in advanced disease. With such care, these patients can expect an acceptable prognosis.
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PMID:[Mesenteric infarct in acute mesenteric vein thrombosis]. 787 19

Evidence is presented that heparin pretreatment produces protective effects on myocardial tissue distinct from its anticoagulant activity. The present study examines the ability of heparin sulfate and N-acetyl heparin (a derivative of heparin devoid of anticoagulant effects) to protect the heart from injury associated with global ischemia and reperfusion. Male New Zealand White rabbits were administered either heparin sulfate (n = 7, 300 U/kg i.v.), N-acetyl heparin (n = 6, 1.73 mg/kg i.v.), or vehicle (n = 6). Two hours after treatment, the hearts were removed, perfused on a Langendorff apparatus, and subjected to 30 minutes of global ischemia, followed by 45 minutes of reperfusion. During reperfusion, creatine kinase concentrations in the coronary sinus effluent were greater in hearts from vehicle-treated rabbits compared with hearts from N-acetyl heparin-treated and heparin-treated rabbits. Left ventricular end-diastolic pressure after 45 minutes of reperfusion in the vehicle-treated group was 64 +/- 15 mm Hg compared with 17 +/- 4 and 10 +/- 3 mm Hg in the heparin-pretreated and N-acetyl heparin-pretreated groups, respectively. Heparin, but not N-acetyl heparin, increased the activated partial thromboplastin time, consistent with its known anticoagulant action. Heparin and N-acetyl heparin inhibited complement-mediated erythrocyte lysis in a concentration-dependent manner. The glycosaminoglycans, in contrast to r-hirudin, reduced complement activation-induced injury in the rabbit isolated heart. The results demonstrate that heparin or N-acetyl heparin, administered to the intact rabbit, protects the isolated heart from subsequent myocardial dysfunction secondary to ischemia/reperfusion. The cardioprotective effects of heparin and N-acetyl heparin are independent of an antithrombin mechanism.
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PMID:Effects of heparin and N-acetyl heparin on ischemia/reperfusion-induced alterations in myocardial function in the rabbit isolated heart. 792 16

Although a functional role of coronary collaterals has been continuously debated, we observed the following facts in our studies during intracoronary thrombolytic therapy: (a) Myocardial ischemia is important for the development of collateral circulation, (b) collaterals can perfuse the infarcted myocardium, and (c) the presence of collaterals prevents the left ventricular aneurysm formation in acute myocardial infarction, even when the amount of the salvaged tissue is small. Thus, coronary collaterals are not merely markers of severe ischemia but help to preserve the functional integrity of the myocardium in the presence of coronary obstruction. We then attempted to promote collateralization to treat patients with angina pectoris. Patients with chronic stable effort angina were treated with heparin followed by treadmill exercise twice a day for 10 days. Treadmill capacity was found to improve in association with an increase in coronary collateral circulation. Heparin treatment of ischemic patients was found to be a noninvasive alternative to percutaneous transluminal coronary angioplasty and coronary bypass surgery for patients who are not candidates for invasive procedures.
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PMID:Effect of coronary collateral circulation on myocardial ischemia and ventricular dysfunction. 794 75

In the natural history of patients with peripheral obliterative arterial disease (POAD) the prognosis of the complaint "intermittent claudication" is relatively good and the amputation rate is presently only about 3%. However, POAD patients carry a high risk of cardiovascular events and their cumultative mortality rate within 10 years is as high as 40-50%. Atherothrombotic events in the coronary and, less frequently, cerebral arteries are by far the first cause of death and disability in these patients. The rationale for antithrombotic drugs in the treatment of POAD lies in the pivotal role of platelet activation and thrombin formation in the evolution of the atherothrombotic lesions, but also in the effect of some of these drugs on the regulation of microcirculatory responses. In acute thrombotic arterial occlusion, Heparin is the "first application" drug, especially in support of interventional revascularisation procedures. Regional thrombolysis often coupled with angioplasty (PTA), or systemic thrombolysis, are effective in revascularisation of especially infrainguinal-supra popliteal occlusions. However, controlled clinical trials are needed. In chronic POAD, intermittent claudication can be improved with a rational walking exercise programme, but, besides pentoxyphilline, especially ticlopidine significantly adds to the benefits of exercise. Regarding districtual progression of atherothrombosis and especially cardiovascular events, both aspirin and ticlopidine have been shown effective in single studies or meta-analyses. In a recent observational study of pooled data the cumulative endpoint including myocardial infarction, stroke and vascular death was reduced by 25 +/- 10% in the generality of patients treated with antiplatelet drugs. Finally, in critical limbs ischemia (CLI), some prostanoid compounds as Iloprost and Prostaglandin E1 favourably influence rest pain and ulcer healing, but less evidence is available on their effects on hard events as amputation and death. In conclusion, following the general indication to "be conservative" in the treatment of these patients, it seems clear that antithrombotic drugs have become by far a key medication in all different phases of POAD.
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PMID:Antithrombotic drugs in peripheral obliterative arterial diseases. 795 59

In a series of 102 patients with angiographically proven cerebral sinus venous thrombosis (SVT) significant differences with arterial cerebrovascular disease were noted with respect to disease onset, reversibility of symptoms, occurrence of epileptic seizures and headache, cerebral blood flow under resting and stimulated conditions, occurrence of intracranial bleedings, and response to heparin therapy. From these findings pathophysiological differences are hypothesized: Whereas arterial cerebral ischemia usually is a monophasic abrupt thrombotic process and there is only a small penumbra, SVT is a continuing process of disequilibrium between prothrombotic and thrombolytic mechanisms; large areas of the brain are only functionally or metabolically disturbed but not irreversibly damaged. Intracranial bleeding in SVT is a consequence of increased venous and capillary pressure and thus occurs more frequently than in arterial thrombotic disease in which capillary pressure is reduced by the thrombosis and bleeding occurs during reperfusion of tissue damaged by ischemia. Heparin treatment in SVT is effective since it shifts the equilibrium away from the prothrombotic side and is able to save large areas of brain tissue that are only reversibly damaged. It improves venous outflow and thus decreases the risk of intracranial hemorrhage, in contrast with the arterial thrombotic disease where heparin increases the risk or at least the severity of intracranial bleedings.
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PMID:Pathophysiological aspects of cerebral sinus venous thrombosis (SVT). 801 60

Popliteal aneurysms may threaten the viability of lower limbs, especially in the case of occlusion and poor run-off. In case of acute ischemia, thrombolysis can be used before surgery to clear the tibial arteries and enhance the results of subsequent bypasses. The procedure starts with an arteriography to show the arterial tree, then a recanalization is attempted. By means of a microcatheter pushed into the thrombosis, Heparin (1000 Units/h) and Urokinase (4,000 Units/h) are injected in situ. Arteriograms are repeated in order to control the placement of the catheter. Anticoagulant and fibrinolytic doses are biologically surveyed. Local and general complications are rare with the new techniques of fibrinolysis. Hemorrhagic complications following surgery are low despite the previous fibrinolytic treatment. Better success rates of bypasses, performed to relieve acute ischemic complications of popliteal aneurysms, should be achieved with this new modality of treatment.
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PMID:[Popliteal aneurysm and leg ischemia: thrombolysis first]. 815 76

Three cases of lower limb, deep venous thrombosis that progressed to ischemia in patients with advanced ovarian cancer are reported. One patient developed frank gangrene of the extremity. Venous stasis, secondary to venous compression from metastatic disease, was the predisposing factor in all cases. Heparin therapy was uniformly unsuccessful in halting progression of thrombosis. Ischemic thrombosis originating from extrinsic venous compression is unlikely to respond to conventional therapy alone. Local external radiation to metastatic sites, given early and possibly in conjunction with conventional treatment methods, may achieve a clinical response by causing a reduction in tumor size and thus relief of venous compression.
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PMID:Lower limb ischemic venous thrombosis in patients with advanced ovarian carcinoma. 850 98

Defibrotide is a polydeoxyribonucleotide sodium salt extracted from mammalian organs. Its mean molecular weight is 15,000-30,000 daltons. Defibrotide contains aptamers, i.e., single-stranded polynucleotides with a well-defined base sequence and composition (5'-GGTTGG-ATT-GGTTGG-3' and 5'-GGTTGG-ATC-GGTTGG-3') that bind thrombin. For the time being, these aptamers are the only ones that have been identified in defibrotide, but there may also be other aptamers that bind proteins other than thrombin. Defibrotide has no anticoagulant activity, but in some other aspects it probably parallels heparin. Heparin is a sulfated polysaccharide sodium salt with a mean molecular weight ranging from 5,000 to 40,000 daltons extracted from mammalian organs. It contains disaccharide sequences of well-defined structure and frequency. Heparin binds an array of proteins, enzymes, and growth factors and shows inhibitory or stimulatory or protective activity. Defibrotide has a spectrum of interesting pharmacological properties that make this drug very useful for the treatment of arterial and venous thrombotic diseases. In fact, defibrotide has profibrinolytic, antithrombotic-thrombolytic, anti-ischemic, and antiatherosclerotic activity and protective activity in shock. What have all the above activities to do with a single drug? The explanation is that atherosclerosis, myocardial, renal, and liver ischemia, hemorrhagic and septic shock, and shock induced by occlusion of splanchnic artery and thrombosis are different facets of the same entity: the polyhedric inflammatory process.
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PMID:An integrated view of the activities of defibrotide. 880 33


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