Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thromboembolism is a complication which represents a major limiting factor in animals with long-term postoperative survival periods following total artificial heart replacement. Thrombi are formed on the artificial valves, the biomaterials and in stagnation areas within the artificial ventricles. In design planning the stagnation areas should be avoided as well as major turbulences. The filling volume should be maximally used for the stroke volume and the epicenter of the membrane should be underneath the valve areas. The ellipsoid heart eliminates stagnation areas and the stroke volume is 82% of the filling volume. The maximum cardiac output is 15.8 l/min. The ellipsoid heart was implanted in 20 female calves; the maximum length of survival was 213 hours. There was no compression of the inferior vena cava and the heart fitted well into the chest of the animals. The cardiac output, self-regulated in the sense of Starling's law, was adequate to perfuse the animals and to allow moderate exercise such as standing. The arterial pressure curves show normal physiological activity. The curves in both atria are unphysiological, owing to relative insufficiency of the valves. The limiting factors were pulmonary insufficiency and surgical complications. The ventricles showed no thrombus formation -- except in one case, in which faulty material was the predisposing cause. It was possible to develop an automatic driving system on the basis of these experiments. Regulation occurred by means of gas flow control in the driving tubes, whereby the form of the gas flow curve provides information on position of the membrane. As soon as the membrane has reached the end-diastolic position, systole is triggered off and lasts until the end-systolic position is reached. If the venous return is increased, the ventricles are filled more rapidly and the heart is driven at a higher rate. One part of the ellipsoid heart is used as ventricle for assisted circulation. The left ventricle is cannulated via the left appendage or the apex. The ventricle relieves the left heart to a large extent and the cardiac output is taken over by the pump placed in a paracorporeal position. The blood is directed back into the thoracic aorta.
 ...
PMID:[Design and haemodynamic evaluation of the ellipsoid heart for total heart replacement]. 26 18

Thrombi formation within artificial ventricles is caused by the effects of biomaterials, stagnation areas, and major turbulences. During systolic and diastolic cycles, stagnation area increase in hearts that are properly designed. Stagnation areas may also occur in properly designed artificial hearts that are not working with a maximum stroke volume. The ellipsoid heart avoids stagnation areas and major turbulences because all the inside surfaces have an adequate washout with blood. The optimum washout of these surfaces is obtained by driving the heart with a constant maximum stroke volume. The cardiac output is regulated according to Starling's law by adjusting the frequency according to the venous return.
 ...
PMID:Artificial heart driven by an automatic driving system. 89 94

Thromboembolic complications represent the main limiting factor in cardiac replacement by totally artificial hearts in calves at present. Thrombus formation within artificial hearts is caused by the appearance of stagnation areas. The ellipsoid heart eliminates stagnation areas by virtue of its production as a one-piece membrane. The heart is driven pneumatically and functions as a diaphragmatic blood pump. The stroke volume is 178 cm3 and the maximal cardiac output 15.8l/Min. Three acute experiments demonstrated a high degree of haemodynamic efficiency without compression of, or interference with surrounding structures, especially the inferior vena cava or the right atrium.
 ...
PMID:[A new design for a totally artificial heart: the ellipsoid heart (author's transl)]. 96 Jul 1

A young woman, successfully treated for Hodgkin's disease with radiation and MOPP chemotherapy, incurred a devastating stroke months after radiation therapy to the neck and other areas. There was no premonitory clinical history of cerebrovascular attacks. Autopsy showed unilateral thrombotic occlusion of the internal carotid artery unassociated with neoplastic or fibrotic annular constriction of the vessel. There was medial thickening and fibroblastic proliferation within the carotid artery. Areas of focal elastic membrane degeneration involved the cervical portions of the carotid. Thrombus was organized to the damaged vessel wall and was propagated into the intracranial vessels. Aneurysm formation and arterial hemorrhages were absent. These vascular changes occurred in an area of extensive radiation (7200 rads). Pathoanatomical studies in this patient indicate that radiation-induced vascular changes were associated with a "delayed" stroke.
 ...
PMID:Delayed cerebrovascular consequences of therapeutic radiation. A clinicopathologic study of a stroke associated with radiation-related carotid arteriopathy. 119 59

Thrombotic and thromboembolic occlusions of arteries and veins represent acute and often life threatening complications requiring immediate therapeutic intervention. The most important clinical manifestations of vascular occlusions are myocardial infarction, peripheral arterial occlusion, pulmonary embolism, deep vein thrombosis and ischemic stroke. The logical approach for the treatment in these indications is the early restoration of blood circulation in order to preserve the organ deprived from oxygen supply and to prevent chronic sequelae. Recanalization by surgical intervention is only possible in some indications and is restricted to special clinics. Thrombolysis induced by agents activating plasminogen imitates the physiologic way of dissolving an occlusive clot by shifting the balance of the hemostatic and fibrinolytic system towards fibrinolysis. Streptokinase was the first effective thrombolytic drug used in patients. In the first years of its usage the identification of the appropriate indication and the dosage and application regimens used were based on little pharmacological knowledge and lack of appropriate dose finding. This resulted in suboptimal therapeutic efficacy and severe bleeding. Development of advanced diagnostic methods, more appropriate dose and application regimens and the development of more specific fibrinolytic drugs like rt-PA led to a remarkable improvement of its benefit-risk ratio and made thrombolysis to a widely accepted form of therapy in thrombotic and thromboembolic diseases. Early restoration of blood flow however is only the starting point of a therapeutic strategy, aiming at minimizing the risk of recurrence.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Thrombolysis: the logical approach for the treatment of vascular occlusions. 152 9

Thrombotic or thromboembolic occlusion of a cerebral artery is the most common pathophysiologic mechanism of acute ischemic stroke. An antithrombotic agent would therefore appear to be an ideal medication for treatment of this condition. Heparin is an effective anticoagulant, but it has poor bioavailability and effects on thrombin and platelets that predispose it to life-threatening complications such as hemorrhage and thrombocytopenia. Low-molecular-weight (LMW) heparins have better bioavailability, a higher anti-Xa:anti-IIa ratio, and less effect on platelets than heparin; yet their heterogeneity has hampered their proper investigation in clinical trials and it has not yet been proven that they exhibit less tendency toward hemorrhage and thrombocytopenia than conventional heparin. The LMW heparinoid, Org 10172, is superior to standard heparin in terms of its bioavailability, anti-Xa:anti-IIa ratio, and lack of effect on platelets. It is less likely than heparin and many LMW heparins to induce thrombocytopenia. Like the various heparins, Org 10172 exhibits dose-dependent hemorrhagic tendencies, yet preliminary studies have found doses that are safe for use in patients with acute ischemic stroke. These studies also suggest that Org 10172 may improve outcome and lessen mortality in this population. A prospective, randomized, double-blind, controlled trial is needed to establish the potential efficacy of Org 10172 in patients who suffer acute or progressing ischemic stroke.
 ...
PMID:Low-molecular-weight heparins and heparinoids and their use in acute or progressing ischemic stroke. 170 55

In a 44-year-old female acute promyelocytic leukemia (APL) presented with abrupt onset of right hemiplegia and aphasia due to occlusion of the left carotid artery at bifurcatio. There was laboratory evidence of disseminated intravascular coagulation (DIC). Thrombotic complications are unusual in APL, even in cases with evidence of DIC. This report aims at underlying the important implication of a correct timely diagnosis in young patients presenting with stroke.
 ...
PMID:Occlusion of the carotid artery as presenting symptom of acute promyelocytic leukemia. 171 25

Thrombus formation in the left atrium and left ventricle is primarily due to stasis of blood which causes activation of the coagulation system. Migration of thrombotic material into the circulation depends on the dynamic forces of the circulation. Atrial fibrillation is the commonest underlying cardiac disorder predisposing to thromboembolism. Rheumatic mitral stenosis, left atrial enlargement, prior myocardial infarction, hypertension, and echocardiographic left ventricular hypertrophy are risk factors for thromboembolic stroke in elderly patients with chronic atrial fibrillation. Non-valvular atrial fibrillation accounts for 45% of cardiac sources of thromboembolic stroke and includes patients with ischemic heart disease, hypertension, thyrotoxic heart disease, hypertrophic cardiomyopathy, chronic sinoatrial disorder, and idiopathic atrial fibrillation. 15% of cardiac sources of thromboembolic stroke are associated with acute myocardial infarction, 10% with left ventricular aneurysm and mural thrombi remote from an acute myocardial infarction, 10% with rheumatic valvular heart disease, and 10% with prosthetic cardiac valves. Mitral valve prolapse, mitral annular calcium, nonischemic cardiomyopathies, infective endocarditis, nonbacterial thrombotic endocarditis, left atrial myxoma, paradoxical embolism associated with congenital heart disease, calcific aortic stenosis, and complex atherosclerotic plaque within the proximal aorta also contribute to thromboembolism.
 ...
PMID:Etiology and pathogenesis of thromboembolism. 176 43

Stroke ranks third as a cause of death in much of the industrial world, surpassed only by heart disease and cancer. Thrombotic and embolic arterial occlusions are the leading causes of cerebral infarction. Once a major cerebral infarction has occurred, therapy is limited to the prevention of complications and rehabilitation. Identification and treatment of stroke-prone patients are now not a standard part of medical practice. However, the proper management of the patient with acute cerebral ischemic or progressing stroke is a subject of debate. Treatment of progressing or acute cerebral ischemia is aimed at prevention of infarction in areas of the brain that are still viable. A number of therapeutic strategies are currently being investigated in the management of ischemic stroke.
 ...
PMID:Medical management of acute cerebral ischemia in the elderly. 186 4

Current findings and controversies between oral contraceptives (OCs) and cardiovascular disease and cancers. Specifically, venous thromboembolism, stroke, myocardial infarction, (MI), atherosclerosis, breast cancer, cervical cancer, endometrial cancer, and ovarian cancer are reviewed. The concentration in the literature is on higher dose estrogen (at least 50 mg) studies which suggest that there is with current users, particularly older women who smoke, a risk of myocardial infarction, venous thrombosis, and subarachnoid hemorrhage. Of the 11 case control studies and 4 cohort studies it appears that venous thrombosis increases in risk with an increase in estrogen content and remains constant for duration of use. However, definitive studies have not been completed on 50 mg doses of ethinyl estradiol (EE) and mestranol (ME). The actual individual risk may be small, 1/1000 current users/year. Thrombotic and hemorrhagic stroke in the 1970s had a risk of 37/100,000 users per year, mostly among smokers 35 years and older with predisposing medical conditions. It is suggested that although there were mixed findings between current and past users in the 1970s low dose current or past users are not substantially at risk. The pre-mid 1970 risk of MI was 7 and 67 cases/100,000 current users ged 30-39 respectively per year. The risk group is similar to stroke. Thrombosis seems to be responsible for the increased risk, rather than atherosclerosis. More data are needed on low preparations; however limited findings suggest little if any risk. There is no available data on the risk for coronary artery atherosclerosis due to OC use, even though 50% of all women die from atherosclerosis-related processes regardless of OC use. Non human primate studies, however, suggest that there may be a reduced risk, perhaps due to the presence of estrogen receptors in arterial endothelium and smooth muscles. Data clearly indicate that the overall risk of breast cancer pre and post 1950 is the same, but age may be a factor with younger OC users at risk; parity protects. The association for lifetime risk, however, cannot be determined since most use occurred in the 1960s. For cervical cancer, 8 found no increased risk and 9 did, and the suggestion is the 5 years use is related to increased risk. Biases related to sexual behavior confound control and analysis of data. The most common cancer in developing countries is cervical, which warrants greater Pap smear screening to reduce this preventable cancer. Protection from cancer of the endometrium occurs for 15 years following 12 months of OC use at a 40% reduced risk. A protected effect is also found for epithelial ovarian cancer, with a 40% risk reduction. It is concluded that health benefits of OCs far exceed the health risks.
 ...
PMID:Long-term health risks and benefits of oral contraceptive use. 209 41


1 2 3 4 5 6 7 8 9 10 Next >>