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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Policosanol, a defined mixture of high molecular weight aliphatic alcohol isolated and purified from sugar cane (Saccharum officinarum, L) wax is a new cholesterol-lowering agent effective in experimental models, healthy volunteers, and patients with type II hypercholesterolemia. Also, policosanol prevents the onset of spontaneously- and experimentally-induced atherosclerotic lesions and cerebral ischemia in Mongolian gerbils. Free radicals are linked to many diseases including atherosclerosis and ischemia/ reoxidation cellular injury. Therefore, in this study the authors evaluate the antioxidant activity of policosanol on rat liver microsomes. The extent of lipid peroxidation was measured by thiobarbituric acid reactive substances (TBARS). When policosanol was administered orally (100 and 250 mg/kg) for up to 4 weeks, a partial prevention of rat in vitro microsomal lipid peroxidation was noted. The formation of TBARS in microsomes isolated from treated rats was significantly decreased by about 50%, when peroxidation was initiated by Fe3+/ADP/ NADPH, Fe2+/ascorbate and CCl4/NADPH-generating system. Also, oral administration of policosanol in rats provides a partial inhibition of lipid peroxidation, but the mechanism supporting such effect remains to be elucidated. This beneficial effect of policosanol on membrane lipid peroxidation may be useful in protecting to some extent against free radical-associated diseases.
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PMID:Effect of policosanol on in vitro and in vivo rat liver microsomal lipid peroxidation. 929 30

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

The prevalence of carotid atherosclerosis in the general population is variable. Also, the relationship between cardiovascular risk factors and carotid atherosclerosis has yet to be clearly defined. We carried out a cross-sectional study of 441 asymptomatic male subjects to investigate possible relationships between extracranial carotid plaques, cardiovascular risk factors and asymptomatic coronary obstructive disease. Carotid atheromatous plaques, detected by means of B-mode ultrasonography, were present in 31.7% of the study population. Prevalence and severity of atherosclerosis were significantly correlated with age, total cholesterol and signs of ischemia upon exercise stress test. However, hypercholesterolemia seemed to play a significant pathogenic role only in the youngest subjects (<55 years old). Our study confirms the high prevalence of asymptomatic carotid plaques in the general population, especially in elderly subjects. The only reversible risk factor related to carotid atherosclerosis is hypercholesterolemia, and this is reversible only at a young age.
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PMID:Carotid artery atherosclerosis and risk factors for stroke in a selected population of asymptomatic men. 958 72

The vascular endothelium controls vasomotor tone by releasing a number of substances like nitric oxide (NO). NO has been shown to play a very important role, because it mediates vasodilation and furthermore inhibits platelet aggregation, expression of adhesion molecules for monocytes and adhesion of neutrophils and it impairs growth of vascular smooth muscle cells. An increased oxidative stress, decreasing the bioavailability of NO, is mainly responsible for a blunted endothelium dependent vasoreactivity. Risk factors for endothelial dysfunction are coronary artery disease, hypertension, hypercholesterolemia, smoking, and aging. Endothelial dysfunction in the presence of these risk factors might contribute to the occurrence of myocardial ischemia, aggravate acute coronary syndromes and accelerate progression of coronary artery disease. Amelioration of blunted endothelial function appears to be a major therapeutical goal to reduce ischemia and clinical events and might even retard progression of coronary artery disease.
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PMID:[The role of endothelial function for ischemic manifestations of coronary atherosclerosis]. 959 5

Drug therapy in stable angina has two aims: the prevention of major cardiac events (such as unstable angina, myocardial infarction, or death) and the control of chest pain and transient myocardial ischemia. Given the low incidence of major cardiac events in patients with stable angina, primary preventive studies are scarce because they require a large sample size and long-term follow-up. Thus far, only aspirin and some lipid-lowering agents have been shown to be effective for this purpose. Antiischemic drugs reduce the imbalance between myocardial oxygen demand and supply, either by reducing oxygen consumption or by increasing coronary blood flow. The ideal approach would be to target drug therapy against the ischemia-inducing factor in each patient. The characteristics of anginal symptoms do not seem to help in selecting medical therapy, whereas a standard exercise test and a provocative test of coronary vasoconstriction may provide useful information in order to select patients who will preferentially respond to either a beta-blocker or a calcium antagonist. The combination of two or more anti-ischemic drugs does not seem to be any more effective than an adequately titrated monotherapy in reducing the occurrence of myocardial ischemia in individual patients. Combination therapy in stable coronary artery disease should include an individually selected and optimally titrated anti-ischemic agent and aspirin, with the addition of a lipid-lowering agent in patients with even mild hypercholesterolemia.
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PMID:Selection of drug therapy in stable angina pectoris. 965 79

Aggregation and disaggregation kinetics of erythrocytes in samples of whole blood were studied using a backscattering nephelometry technique. Blood was drawn from normal subjects and from patients suffering from different diseases: chronic glomerulonephritis, systemic lupus erythematosus, hereditary hypercholesterolemia, pulmonary hypertension, intestinal tumors preoperatively (age > 60 years), psoriasis, psoriatic arthritis, ischemia and ischemia with diabetes. Blood samples of healthy donors were used as controls. The backscattering signal in the erythroaggregometer was processed according to algorithms yielding quantitative data on the full amplitude of aggregation, characteristic times of spontaneous aggregation, average hydrodynamic strength of all aggregates and, whenever possible, additionally, strength of the largest aggregates. The obtained results confirm that the complexity of erythrocyte aggregation kinetics requires multiparametric description which, when applied to clinical material, enables the differentiation of aggregation characteristics between diseases.
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PMID:Clinical application of the measurement of spontaneous erythrocyte aggregation and disaggregation. A pilot study. 969 29

It has been shown that hypercholesterolemia (HCh) exaggerates the microvascular dysfunction that is elicited by ischemia and reperfusion (I/R). The objective of this study was to determine whether oxidants contribute to the exaggerated inflammatory responses and enhanced albumin leakage observed in HCh rat mesenteric venules exposed to I/R (10 minutes of ischemia and 30 minutes of reperfusion). Intravital videomicroscopy was used to quantify the number of adherent and emigrated leukocytes, albumin extravasation, platelet-leukocyte aggregation in postcapillary venules, and the degranulation of adjacent mast cells. Oxidation of the fluorochrome dihydrorhodamine 123 (DHR) was used to monitor oxidant production by venular endothelium. I/R was shown to elicit an increased DHR oxidation in venules of both control and HCh rats, with the latter group exhibiting a significantly larger response. Treatment with either oxypurinol or superoxide dismutase largely prevented the leukocyte recruitment, platelet-leukocyte aggregation, mast cell degranulation, and enhanced DHR oxidation elicited by I/R in HCh rats. The enhanced albumin leakage was reduced by superoxide dismutase but not by oxypurinol. These results indicate that HCh amplifies the oxidant stress elicited by I/R and that interventions that blunt the oxidant stress effectively attenuate the leukocyte, platelet, and mast cell activation that result from I/R.
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PMID:Hypercholesterolemia enhances oxidant production in mesenteric venules exposed to Ischemia/Reperfusion. 976 30

ALTERATIONS OF THE ENDOTHELIUM: Because of its anatomic position between circulating blood and smooth muscle cells, the vascular endothelium is a prime target for cardiovascular diseases such as hypertension, hypercholesterolemia, diabetes or ischemia. The morphological changes occurring in the endothelium have been known for many years, but it was only recently that the functional alterations have been described. IMPACT OF NO: Under physiological conditions, the vascular endothelium plays a protective role by secreting relaxation factors. In the disease state, the synthesis and release of NO may be reduced or even abolished. The exact significance of endothelium-dependent vasodilatation disorders remains a topic of research, but the properties of NO strongly suggest it is involved in several diseases. For some diseases it is still a question as to whether the observed anomalies are the cause or the consequence of the underlying disease. DISEASE-SPECIFIC CHANGES: NO is known to be reduced in atherosclerosis, either because of less synthesis or accelerated degradation. In different experimental modules of hypertension, the baseline level of NO release appears to be decreased. Conversely, NO release can be normal, reduced or increased in diabetes. In heart failure, there appears to be not only a permanent alteration in NO secretion, but also an increase in factors stimulating vascular contraction, contributing to an altered capacity for vascular adaptation in these patients.
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PMID:[Nitric oxide (NO), vascular protection factor. NO related cardiovascular diseases]. 976 31

The epidemiology of atherosclerotic peripheral arterial disease (PAD) has rarely been studied in Asia. A prospective vascular registry consisting of 510 Chinese patients with PAD from a teaching hospital in Hong Kong disclosed a male/female ratio of 1.6:1.0 with a mean age of 72 years. The predominant pattern was femoropopliteal occlusive disease (49%). Half of all patients had tissue loss on presentation, more so in women (67%) than men (38%). Demographic and biochemical risk factors examined showed many similarities with the West, included smoking (59%), hypertension (55%), diabetes mellitus (42%), hypercholesterolemia (55%), elevated low density lipoprotein (LDL) (60%), triglycerides (31%), hyperfibrinogenemia (62%), and hyperglycemia (49%). Chinese female patients with PAD were older and had a high prevalence of diabetes mellitus (54%). Smoking is less a problem in women (28%). They suffered predominantly from femoropopliteal and distal vessel disease, and two-thirds presented with tissue loss. Female patients also have significantly higher levels of fasting glucose, cholesterol, triglyceride, LDL, and very low density lipoprotein (VLDL). Male patients were mostly smokers (80%) with a higher proportion of aortoiliac disease. Critical ischemia in the form of tissue loss was associated with female sex (p < 0.001), age (p < 0.001), nonsmoking (p < 0.001), diabetes (p < 0.005), a low hemoglobin/hematocrit (p < 0.001), a high white blood cell count (p < 0.001), and high levels of fibrinogen (p < 0.01) and cholesterol (p < 0.05). An increasing incidence of PAD was noted in Hong Kong. Most of the patients present late with advanced ischemia. It is possible that this disease pattern represents only a fraction of the true incidence of PAD in the territory.
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PMID:Epidemiology of atherosclerotic peripheral arterial occlusive disease in Hong Kong. 988 Apr 33

To determine the clinicohematological factors predictive for the appearance of major vascular complications (MVC) in patients with essential thrombocythemia (ET), 148 consecutive such patients were retrospectively assessed for the development of MVC during a median follow-up of 58.5 months. Seventy-seven patients had vascular risk factors, and 37 a history of MVC at ET diagnosis. Forty-nine MVC were registered in 33 patients during the follow-up period. The actuarial probability of MVC was 27% at 6 years in the whole series, 35.6% for patients above 60 years, and 21.4% for patients younger than 60 years, whereas only one of the 36 patients younger than 45 years had MVC. At multivariate analysis, age >60 years, history of major ischemia and hypercholesterolemia were the variables associated with an increased MVC risk. These results suggest that all ET patients above 60 years should be treated, whereas in younger patients treatment decisions should be primarily based on the existence of risk factors for MVC.
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PMID:Major vascular complications in essential thrombocythemia: a study of the predictive factors in a series of 148 patients. 1002 86


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