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)

Peripheral occlusive arterial disease (P.O.A.D.) is one of the situations in which hemorheological abnormalities are usually described. However the clinical relevance of hemorheological measurements in angiologic practice remains to be defined. The aim of the study was to investigate whether hemorheological disturbances are associated with alterations in oxygen diffusion and prognosis of the arterial disease. Three groups of patients were included in this work. First, a study was realized on 160 nondiabetic P.O.A.D patients (suffering from intermittent claudication to critical limb ischemia) in order to evaluate the possible influence of hemorheological disturbances on oxygen diffusion in distal tissue. A control group of 30 subjects matched for age and sex was also studied. A second study was performed on 80 diabetic P.O.A.D. patients (stage III and IV of Leriche and Fontaine classification) to determinate if hemorheological parameters could be considered as prognostic factors in the P.O.A.D. course. Hemorheological parameters were determined on different devices: red blood cell (RBC) aggregation by Myrenne aggregometer, blood and plasma viscosities by MT 90 falling ball viscometer. Transcutaneous oxygen pressure was measured by Radiometer TCM2 oxygen monitor. Several rheological parameters of non diabetic patients suffering from P.O.A.D. were significantly higher than those of control group subjects : blood viscosity (p < 0.05), plasma viscosity (p < 0.001), erythrocyte rigidity index (p < 0.01) and fibrinogen level (p < 0.0001). In the nondiabetic patients TcPO2 was negatively correlated with RBC aggregation, erythrocyte rigidity index and hematocrit /viscosity ratio. The diabetic patients who needed major amputation (above or below knee) presented significantly increased hemorheological parameters (blood viscosity, RBC aggregation, RBC rigidity index, hematocrit/viscosity ratio, fibrinogen level) compared to diabetic who had not been major amputated (no amputation or only toes' amputation). Our finding suggests that hemorheological factors (1) may influence oxygen transfer to distal tissues by maldistribution of blood flow and (2) may have prognostic significance in chronic peripheral occlusive arterial disease.
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PMID:[Rheology and occlusive arterial disease of the legs]. 896 45

There has been a prejudice that diabetes modulates the function of saphenous vein in a manner that predisposes to bypass graft failure, although most of the evidence accrues from animal studies. We have investigated the effect of diabetes on the vasodilator responses and ultrastructure of saphenous vein harvested from patients undergoing infrainguinal bypass surgery for limb salvage and the development of stenoses within the vein grafts. Of 55 consecutive patients undergoing vein bypass surgery for critical ischemia, 16 (29%) were diabetic: diabetes was not a risk factor for graft stenosis, which occurred in 17 of 56 (30%) grafts. Endothelium-dependent relaxation by nitric oxide pathways stimulated after receptor activation (bradykinin and thrombin) was not different in vein rings from diabetic (n = 12) and nondiabetic patients (n = 12). Prostarioid-mediated vasorelaxation was absent in vein rings from diabetic patients, and the production of 6-keto prostaglandin F(1alpha) (PGF(1alpha)) from diabetic vein was only 66 +/- 27 pg x cm-2 x min-1 compared with 112 +/- 20 pg x cm-2 x min-1 from control vein (P = 0.011). Fibrinogen-mediated vasorelaxation, normally inhibited by K+ channel blockers, was negligible in vein from diabetic patients. No ultrastructural differences were observed between the endothelium of saphenous vein harvested from diabetic and nondiabetic patients. However, diabetes was associated significantly with the presence of spiraled collagen in media. The maintenance of receptor-activated stimulation of nitric oxide pathways and the damping of the response to fibrinogen in saphenous vein endothelium may provide, in part, for the good prognosis of vein graft surgery in diabetic patients: diabetes is not a risk factor for early (12 months) infrainguinal vein graft stenosis.
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PMID:The influence of diabetes on the vasomotor responses of saphenous vein and the development of infra-inguinal vein graft stenosis. 897 Oct 90

Angiotensin-converting enzyme (ACE) inhibitors have proven to be effective in the reduction of ischemia/reperfusion damage after myocardial ischemia. Whether this favorable effect can be related to other models of ischemia and reperfusion has not yet been investigated. Therefore, we studied in a model of syngeneic liver transplantation in the rat the effect of recipient enalapril treatment on postischemic liver injury. Untreated animals served as the control group. Treatment with enalapril was started 5 minutes before reperfusion by intravenous infusion of enalapril at a dosage of 5 mg/kg/h. By means of in vivo microscopy, the sinusoidal perfusion rate and leukocyte adherence in sinusoids and postsinusoidal venules were analyzed during 45 to 60 minutes of reperfusion. Liver function was monitored by measuring bile output over a period of 60 minutes. Analysis of coagulation factors (prothrombin time, factor V, fibrinogen) and liver enzymes (alanine transaminase [ALT], aspartate transaminase [AST]) served for the evaluation of organ dysfunction and damage secondary to ischemia/reperfusion injury. The sinusoidal perfusion rate was significantly improved by enalapril treatment (94.7% [1.0] vs. 75.3% [3.8]; mean [SEM]; P = .005). In addition, leukocyte-sticking in both liver sinusoids and postsinusoidal venules was remarkably reduced in enalapril-treated animals as compared with controls (stickers/lobule: 21.0 [3.3] vs. 59.2 [2.1]; P = .0004; stickers/mm2 venular surface: 20.5 [4.7] vs. 110.3 [18.1]; P = .0004). Moreover, bile output was increased (1.13 [0.35] vs. 0.43 [0.18] g bile/60 min x 100 g liver; P = .06). Values for PT (22.5% [2.1] vs. 9.7% [1.8]; P = .005), factor V 99.4% [9.5] vs. 49.5% [8.5]; P = .007), and fibrinogen (64.1% [7.7] vs. 12.8% [3.2]; P = .001) were significantly improved, paralleled by a remarkable reduction in serum ALT (1,428 U/L [190] vs. 2,315 [248]; P = .02). Our data show for the first time that ACE inhibition in the liver recipient by enalapril attenuates hepatic ischemia/reperfusion damage after experimental liver transplantation. Our results may offer a novel approach to reduce ischemia/reperfusion injury in clinical liver transplantation.
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PMID:Angiotensin-converting enzyme inhibition by enalapril: a novel approach to reduce ischemia/reperfusion damage after experimental liver transplantation. 904 13

Results of infrainguinal bypass surgery may be better in diabetic patients compared with nondiabetic patients. One important determinator of outcome in these operations is the peripheral vascular resistance (PR). The aim of the present prospective study is to evaluate whether there is a difference in PR in diabetic and nondiabetic patients with critical limb ischemia. The two patient groups (n = 11 for each) were matched for toe pressure, age, gender, and outflow vessel, PR was measured intraoperatively during infrainguinal bypass surgery by controlled infusions of autologous blood. The resistance was significantly higher in the diabetic group (p < 0.05), as compared to the nondiabetic group. Except for fibrinogen that tended to be higher in diabetics (p = 0.07), blood parameters, blood pressures and angiographic scoring of run-off were similar in both groups. This finding of higher PR in diabetic patients with critical limb ischemia compared with matched nondiabetic ischemic patients suggests that a low PR is not the reason for the positive results of infrainguinal bypass surgery in diabetic patients.
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PMID:Patients with diabetes and critical limb ischemia have a high peripheral vascular resistance. 914 May 95

We conducted a study using diffusion-weighted (DWI) and perfusion-weighted (PWI) magnetic resonance imaging (MRI) to evaluate the efficacy of thrombolysis in an embolic stroke model with recombinant tissue plasminogen activator (rt-PA) and hirulog, a novel direct-acting antithrombin. DWI can identify areas of ischemia minutes from stroke onset, while PWI identifies regions of impaired blood flow. Right internal carotid arteries of 36 rabbits were embolized using aged heterologous thrombi. Baseline DWI and PWI scans were obtained to confirm successful embolization. Four animals with no observable DWI lesion on the initial scan were excluded; therefore, a total of 32 animals were randomized to one of three treatment groups: rt-PA (n = 11), rt-PA plus hirulog (n = 11), or placebo (n = 10). Treatment was begun 1 h after stroke induction. Intravenous doses were as follows: rt-PA, 5 mg/kg over 0.5 h with 20% of the total dose given as a bolus; hirulog, 1 mg/kg bolus followed by 5 mg/kg over 1 h. MRI was performed at 2, 3, and 5 h following embolization. Six hours after embolization, brains were harvested, examined for hemorrhage, then prepared for histologic analysis. The rt-PA decreased fibrinogen levels by 73%, and hirulog prolonged the aPTT to four times the control value. Posttreatment areas of diffusion abnormality and perfusion delay were expressed as a ratio of baseline values. Significantly improved perfusion was seen in the rt-PA plus hirulog group compared with placebo (normalized ratios of the perfusion delay areas were as follows: placebo, 1.58, 0.47-3.59; rt-PA, 1.12, 0.04-3.95; rt-PA and hirulog, 0.40, 0.02-1.08; p < 0.05). Comparison of diffusion abnormality ratios measured at 5 h showed trends favoring reduced lesion size in both groups given rt-PA (normalized ratios of diffusion abnormality areas were as follows: placebo, 3.69, 0.39-15.71; rt-PA, 2.57, 0.74-5.00; rt-PA and hirulog, 1.95, 0.33-6.80; p = 0.32). Significant cerebral hemorrhage was observed in one placebo, two rt-PA, and three rt-PA plus hirulog treated animals. One fatal systemic hemorrhage was observed in each of the rt-PA groups. We conclude that rt-PA plus hirulog improves cerebral perfusion but does not necessarily reduce cerebral injury. DWI and PWI are useful methods for monitoring thrombolysis.
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PMID:Improved perfusion with rt-PA and hirulog in a rabbit model of embolic stroke. 914 22

Symptomatic end-stage arterial disease in coronary artery or peripheral arterial occlusive disease represents an increasing clinical problem as cardiovascular mortality in these patient groups has declined due to improved secondary prevention. While in peripheral arterial occlusive disease amputation with subsequent life-long physical disability is the major problem, patients with end-stage coronary artery disease and refractory angina pectoris repeatedly report to the emergency ward with the clinical symptoms of unstable coronary syndromes, but myocardial infarction is generally ruled out. For these patients long-term intermittent urokinase therapy has been developed as an alternative treatment modality. Potential mechanisms for clinical effectiveness include improvement of rheological blood properties, thrombolysis of non-occluding arterial thrombi and possibly plaque regression. In coronary artery disease urokinase is applied as an intravenous bolus injection of 500,000 IU urokinase three times a week over a period of 12 weeks. This leads to a marked reduction of fibrinogen by about 35% and of clinical symptoms by around 70% accompanied by a reduction of exercise-induced myocardial ischemia. In observational studies in patients with peripheral arterial occlusive disease injections of 500,000 IU of urokinase were usually given daily for a shorter time period of three to four weeks with a clinical success rate, defined as a cessation or marked reduction of rest pain and/or salvage of a limb, of around 50%. Given the state of critical ischemia in both entities of atherosclerotic disease, long-term intermittent urokinase therapy represents a promising antiischemic approach. In particular in patients with peripheral arterial occlusive disease randomized controlled trials with prolonged treatment periods, which are likely to improve clinical results, are warranted.
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PMID:Low-dose intermittent urokinase therapy in chronic symptomatic end-stage arterial disease--clinical relevance for patients with coronary artery disease or peripheral arterial occlusive disease. 918 59

The epidemiologic approach to investigation of atherosclerotic cardiovascular disease has provided many insights into the preclinical and clinical spectrum of the disease. The hazard of developing atherosclerotic cardiovascular disease is substantial with coronary heart disease (CHD), the most common and most lethal feature. The outlook in those who manage to survive the initial episode is also serious, with a 10-year mortality rate of 37% for persons with angina and a 55% rate for those sustaining a myocardial infarction. Fifteen percent of persons developing CHD present with a fatal event, and 38% of infarctions go unrecognized. The presence of atherosclerosis in one vascular territory imposes an increased risk of its appearing in another area at two to six times the general population rate. The major cardiovascular risk factors adversely affect all arterial vascular territories so that correction of risk factors targeted at one particular atherosclerotic outcome may also favorably influence the other risk factors. Coronary disease is the most prevalent lethal hazard of hypertension, dyslipidemia, glucose intolerance, and cigarette smoking. These risk factors cluster and optimal therapy must improve the whole risk profile. Women share the same risk factors for CHD as men. Although women have a lower absolute risk for most risk factors, a high total/HDL cholesterol ratio, left ventricular hypertrophy, and diabetes each tend to eliminate the female advantage. Menopause also promptly escalates risk threefold. Although women tend to have a lower incidence than men, the initial attack is just as highly lethal in women, and their subsequent outlook as survivors is at least as serious as for men. Sudden death is a pre-eminent feature of coronary disease and cardiac failure. Coronary disease increases sudden death risk 3.3-fold and cardiac failure 4.8-fold. Sudden death incidence varies in relation to the same cardiovascular risk factors as coronary heart disease, with no unique risk factors identified. However, multivariate combinations of these in a profile can identify high-risk candidates for sudden death as well as coronary attacks in general. The key to prevention of sudden death is to prevent coronary attacks and cardiac failure. Despite aggressive cardiac revascularization and treatment of hypertension, congestive heart failure (CHF) has not decreased in prevalence, and innovations in the treatments of overt failure have not substantially improved survival. Median survival is only 1.7 years for men and 3.2 years for women. The conditional probability of developing CHF can be estimated using a logistic function comprised of age, systolic pressure, vital capacity, heart rate, ECG-left ventricular hypertrophy (LVH), glucose intolerance, x-ray enlargement, and presence of CHD and heart murmurs. Eighty percent of CHF events occur in persons in the upper quintile of multivariate risk. Continued clinical, metabolic, and epidemiologic research have expanded and refined atherosclerosis risk factors. The lipid connection is now concerned with the apoprotein makeup of the lipids, subfractions of lipids, and Lp(a). The diabetic influence is now focused on insulin resistance. Ambulatory monitoring is being used to evaluate blood pressure and silent ischemia. Fibrinogen and leukocyte counts have emerged as possible indicators of unstable lesions. Prospects for primary and secondary prevention are good if public health measures, health education, and preventive medicine are implemented based on existing knowledge of correctable or avoidable risk factors. The potential for more effective prevention continues to expand, and great advances have already been made in countries where aggressive preventive measures have been implemented to correct the major established risk factors.
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PMID:Hazards, risks, and threats of heart disease from the early stages to symptomatic coronary heart disease and cardiac failure. 921 Oct 12

Recent evidence suggests that apolipoprotein E (ApoE) plays a role in neurologic disease. This experiment compared the neurologic and histologic outcome of ApoE-deficient mutant and wild-type mice subjected to a 60- or 90-minute episode of middle cerebral artery filament occlusion and a recovery interval of 24 hours. With 60 minutes of ischemia, there was no mortality. Apolipoprotein E-deficient mice had larger infarcts (cortex: ApoE deficient = 20 mm3 +/- 12, wild-type = 9 +/- 7 mm3, P = 0.03; subcortex: ApoE deficient = 22 +/- 7 mm3, wild-type = 16 +/- 7 mm3, P = 0.07). Hemiparesis was less severe in wild-type animals (P = 0.02). After 90 minutes of ischemia, mortality in ApoE-deficient mice (n = 10) was 40% versus 0% in wild-type mice (n = 10; P = 0.09). Intraparenchymal hemorrhage was found in 3 of the 4 dead mice. No difference in cortical (ApoE deficient = 37 +/- 8 mm3; wild-type = 31 +/- 18 mm3; P = 0.49) or subcortical (ApoE deficient = 30 +/- 11 mm3; wild-type = 32 +/- 18 mm3; P = 0.78) infarct volumes was present among survivors. ApoE-deficient mice had a prolonged activated partial thromboplastin time and increased fibrinogen concentration. This data supports the hypothesis that apolipoprotein E plays a role in the pathophysiology of ischemic brain damage.
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PMID:Apolipoprotein E-deficient mice have increased susceptibility to focal cerebral ischemia. 927 Apr 92

The Fragmin and/or Early Revascularisation during Instability in Coronary Artery Disease (FRISC II) trial will, in a prospective multicenter factorially randomized study, compare the efficacy of 3 months continuation of subcutaneous treatment with the low-molecular-weight heparin dalteparin (Fragmin) with that of placebo and will also compare a direct invasive strategy with a stepwise selective approach with regard to the utilization of coronary angiography and revascularization in patients with unstable coronary artery disease. The primary endpoints are death or myocardial infarction after 3 and 6 months respectively. Secondary endpoints are the same events after 12-24 months and also cardiac symptoms, exercise capacity, and/or signs of myocardial ischemia, readmission, and costs. Analyses will also be made of subgroups based on inclusion diagnosis, initial elevation of biochemical markers of myocardial damage, elevation of fibrinogen or C-reactive protein, signs of ischemia in electrocardiography at rest or at continuous 24-hour ischemia monitoring, and left ventricular function at echocardiography. Altogether, 3,100 patients will be recruited in 65-70 Scandinavian centers. Completion of follow-up is anticipated in the second half of 1998. The FRISC II study will further elucidate new alternatives for antithrombotic, invasive, and individually tailored treatment of unstable coronary syndromes.
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PMID:Long-term low-molecular-weight heparin (Fragmin) and/or early revascularization during instability in coronary artery disease (the FRISC II Study). 929 73

Current management of atherosclerotic diseases consists primarily of medical therapy designed to increase oxygen supply to the heart, the brain, retinal vessels, or lower limbs. The development of these diseases is based on atherosclerotic changes induced by risk factors such as elevated levels of fibrinogen and lipoproteins. These risk factors are related to a dramatic deterioration of the hemorrheologic pattern, which reduces perfusion. Consequently, attempts are now being made to treat ischemia via hemorrheological intervention. A new treatment modality utilizing the heparin-induced extracorporeal low-density lipoprotein (LDL) precipitation (HELP), offers the possibility of obtaining therapeutic success not only in cases of severe hypercholesterolemia but also in the field of hemorheology. With HELP a safe and rapid reduction of fibrinogen and lipid fractions has become feasible, thus providing acute improvements of red cell aggregation, of the filterability of blood cells, of whole-blood and plasma viscosity, and thereby of microcirculation. Because cerebrovascular diseases are known to be related to disturbances of the hemorrheological situation, the HELP system is used in the Department of Electrobiology of Graz for the treatment of acute stroke, cerebral multi-infarct disease, and occlusions of retinal arteries.
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PMID:Heparin-induced extracorporeal fibrinogen/LDL precipitation (HELP): a promising regimen for the treatment of vascular diseases. 940 28


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