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

Cerebral ischemia and infarction have been produced in the Rhesus monkey using an autologous clot embolization technique. Preliminary findings suggest that cerebral arteriography may be used to study experimental cerebral infarction and ischemia, and the resulting cerebral edema and also that cerebral arteriography may be used as a tool for the evaluation of various types of therapy now used clinically in the treatment of these entities. The present experimental study in the monkey suggests that whereas steroid therapy initiated immediately following the onset of cerebral ischemia reduces morbidity and hastens clinical recovery, pretreatment with steroids in these same cases of cerebral ischemia may be hazardous and may increase the risk of cerebral infarction.
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PMID:Experimental cerebral infarction in the monkey. Radiographic evaluation of steroid therapy. 82 Jun 68

The effect of intravenous infusion of 10 per cent glycerol on regional cerebral blood flow (using hydrogen bolus and Xenon-133 (133Xe) clearance methods) and metabolism was investigated in 57 patients with recent cerebral infarction. Hemispheric blood flow (HBF) increased, together with increase in regional cerebral blood flow (rCBF) and cerebral blood volume (rCBV), in foci of brain ischemia. Hemispheric oxygen consumption (HMIO2) decreased together with hemispheric respiratory quotient. Systemic blood levels of glucose, lactate, pyruvate, and triglycerides also increased after glycerol while free fatty acids (FFA) and inorganic phosphate (Pi) decreased. Hemispheric glucose consumption was unaltered after glycerol so that hemispheric glucose to oxygen ratio tended to rise. Pyruvate and lactate production by brain was unchanged. Glycerol moved across the blood brain barrier into brain and cerebrospinal fluid (CSF). Release of FFA and Pi from infarcted brain was reversed by glycerol. Total phosphate balance was maintained actoss brain both before and after glycerol infusion. Triglycerides increased in CSF after glycerol, originating either from cerebral blood or as a result of lipogenesis in cerebral tissue. The EEG Recording and neurological status of the patients improved despite decreased brain oxygen consumption. Results of this study suggest that after intravenous infusion of 10 per cent glycerol in patients with recent cerebral infarction, glycerol rapidly enters the CSF and brain compartments and favorably affects the stroke process in two ways: first, by redistribution of cerebral blood flow with increase in rCBF and rCBV in ischemic brain secondary to reduction in focal cerebral edema; and second glycerol may become an alternative source of energy either by being directly metabolized by the brain, or indirectly, by enhancing lipogenesis, or by both processes. Involvement of glycerol in lipogenesis with esterification to accumulated FFA might lead to improved coupling of oxidative phosphorylation, a hypothesis that fits the finding of improved neuronal function despite further decrease in cerebral hemispheric oxygen consumption.
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PMID:Circulatory and metabolic effects of glycerol infusion in patients with recent cerebral infarction. 109 Mar 93

Cerebrovascular insufficiency arises from multiple causes, including cardiovascular insufficiency and local obstacles to the blood flow in the "four brain vessels". These obstacles are caused by primary thrombosis, by embolism, or by stenosing or ectatic arteriosclerosis. As there are anastomoses in the extra- and intracranial vessels, a collateral circulation can arise when hemodynamic conditions (blood pressure etc.) are adequate; this is also necessary for the preservation of these collaterals in later stages. Since particular hemodynamic conditions (terminal and watershed zones) have particular roles, different patterns of infarction can arise. Local obstacles to the blood flow can be subjected to vascular surgery as a preventive measure or even for vital conditions. The details of cerebral blood flow and brain viability have not become completely clear from the results of modern experimentation. The setting up of research institutes to concentrate on arteriosclerosis and ischemia in collaboration with clinical centers devoted to coronary and cerebral infarction seems to be very necessary.
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PMID:[Cerebrovascular insufficiency (author's transl)]. 120 96

Recent animal studies have suggested that there exists an activated subpopulation of circulating granulocytes which plays an important part in microvascular sequestration and tissue injury during shock and ischemia. In this respect, spontaneous granulocyte activation in form of pseudopod formation, a manifestation of actin polymerization, is a high risk for microvascular entrapment. The present investigation was carried out to determine if there is a significant difference in pseudopod formation in vitro between granulocytes obtained from healthy volunteers without symptoms and patients with acute cardiovascular illnesses. Blood samples from 25 healthy volunteers, 12 patients with acute myocardial infarction (AMI) and 12 patients with acute cerebral infarction (ACI) to determine spontaneous pseudopod formation in granulocytes with a high resolution light microscope over a period of several hours. The results revealed that the mean percentage of cells with pseudopod formation in the control group was below 10% in the first 3 hours, and increased to about 50% at 12 hours. In AMI patients, the level of activation within the first hour was not significantly different from the controls, but it rose rapidly to 90% in 4 to 5 hours. Patients with cerebral infarction, however, showed no significant difference from the control group. When the granulocytes of healthy subjects were incubated in plasma of AMI, the cells were activated similar to AMI granulocytes in their own plasma. When AMI plasma was serially diluted with Ringer's solution, the activation curve fell successively. These results indicate that AMI patients' blood contains plasma factor(s) which can activate granulocytes at a more rapid rate than controls.
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PMID:Spontaneous activation of circulating granulocytes in patients with acute myocardial and cerebral diseases. 130 82

Proton nuclear magnetic resonance spectroscopy is a noninvasive technique allowing the localized, in vivo detection of proton-containing brain metabolites. We used this technique to study eight patients with cerebral infarction or ischemia. A stimulated echo-pulse sequence with chemical shift imaging was used to acquire spectra from multiple contiguous 4-cc volumes extending from the site of ischemia to the opposite hemisphere. Six patients had a reduction in the signal from N-acetyl groups (NAG) in the stroke area compared with controls, and those with the lowest NAG to phosphocreatine/creatine ratios had the least recovery of function. Lactate was observed within the infarcted region in two patients at 9 and 11 days after infarction and may have been present in other patients up to 15 weeks after stroke.
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PMID:Multivoxel 1H-MRS of stroke. 132 Feb 20

Fetal rat cortical cells have been shown previously to survive at the periphery of cerebral infarction. The present study was designed to examine the ability of fetal cells to survive at the edge of the central core of ischemia. In three groups of 8 adult Sprague-Dawley rats, fetal cortical cells from ED 16 were stereotactically transplanted at 3 h, 24 h, and 7 days after unilateral middle cerebral artery occlusion. In 6 rats, fetal cells were transplanted by using the same coordinates, without arterial occlusion, for control. In the ischemic groups, overall graft survival was 85%, and in the control group, all grafts survived. Graft survival was determined by light microscopy. No significant difference was found in the survival of grafts transplanted at different intervals after middle cerebral artery occlusion. It is concluded that fetal cortical cells can survive in cerebral tissue undergoing severe ischemic change.
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PMID:Fetal cortical cells survive in focal cerebral infarct after permanent occlusion of the middle cerebral artery in adult rats. 140 23

The focal brain ischemia with disturbance of cerebral venous drainage often lead to brain edema and hemorrhagic infarction and make mortality and morbidity worse. So we tried to make sure of this fact using a middle cerebral artery (MCA) occlusion model in adult cat. The MCA was exposed by the transorbital approach and temporally obstructed by Zen's clip. We divided the animals into two groups of eight cats. One group is only MCA occlusion group (sham group) and the other in MCA occlusion with disturbance of venous drainage (VRD group). We ligated bilateral external jugular vein (EJV) and internal jugular vein (IJV) and injected embolic sources from the left EJV to obstruct the venous system of cat brain. The pressure of superior sagittal sinus was increased up to 18.7 +/- 5.3 mmHg by this method. A cranial window was made above the ectosylvian gyrus, which has poor anastomosis. The reactivity of pial arteriole and regional cerebral blood flow (rCBF) were observed through the window. And histological brain examination was also performed. The result was that the reactivity of pial arterioles was severely disturbed in VRD group. The area of cerebral infarction and edema were also significantly expanded in VRD group. Considering from these facts, when the venous drainage was disturbed, cerebral perfusion pressure relatively decrease. Because of the decrease in cerebral perfusion pressure, cerebral infarction and edema probably expand to the area so called penumbra.
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PMID:[The focal brain ischemia with disturbance of venous drainage]. 141 37

Twenty patients with primary cardiac tumors were operated on during the past ten years. The age of 15 female and 5 male patients ranged from 17 to 73 years. Eighteen patients had myxomas, 16 of which located in the left atrium and 2 in the right atrium. Systemic embolism occurred in 8 patients, subsequently caused cerebral infarction in 4, ischemia of extremities in 2, myocardial infarction in 1 and pulmonary infarction in 1. Emergency operation was performed in 5 patients because of severe congestive heart failure. In all cases, removal of myxoma was performed together with the excision of the wall to which the pedicle attached with the use of cardiopulmonary bypass. One patient with pulmonary infarction underwent resection of the infarcted lung simultaneously. Only one patient with severe heart failure died of pulmonary insufficiency one month after the operation. Another patient with cerebral infarction underwent clipping of cerebral aneurysm which appeared later in the infarcted area. The 17 patients including the latter patient showed a good recovery and no local recurrence during the follow-up period of 1 to 120 months. Two patients had malignant tumors, which were malignant fibrous histiocytoma of the left atrium and leiomyosarcoma of the pulmonary artery, respectively. Both of these rare tumors were resected noncuratively and led to the death because of their local recurrence with distant metastasis, though they received adjuvant chemotherapy. The symptoms, complications, diagnoses, surgical treatment and outcome of the primary cardiac tumors are reviewed in this study.
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PMID:[Surgical treatment of primary cardiac tumors]. 143 1

The introduction of positron emission tomography (PET) as a powerful imaging modality has played a major role in the understanding of the pathophysiological bases for cerebrovascular disorders. PET is the only technique that allows measurement of regional cerebral blood flow, blood volume, oxygen extraction fraction, and oxygen and glucose metabolism with detail and accuracy. Using PET, these physiological parameters can be measured to determine the extent of the disease from the early stages of cerebrovascular disorders to acute cerebral infarction. Significant hemodynamic and metabolic abnormalities are noted in chronic ischemia, but no structural changes are noted on anatomic images. PET studies have shown that in many patients in the early phases (10 to 12 hours) of clinically diagnosed acute stroke, a substantial area of ischemia exists, which, if untreated, will become irreversibly damaged. Similar to the results achieved in patients with acute myocardial infarction, appropriate intervention in patients with cerebrovascular disorders may significantly reduce the extent of injury to the brain. PET also has been useful in predicting functional recovery and monitoring the effects of various therapeutic approaches. Although functional imaging of the brain with single photon emission computed tomography can successfully be used in the investigation of several disorders of the brain, its role in cerebrovascular disorders is quite limited. PET is a unique modality that studies ischemic diseases of the brain, and it potentially could play a significant role in the management of patients with cerebrovascular disease. This will be further realized when aggressive approaches are used routinely in the future.
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PMID:Positron emission tomography in cerebrovascular disorders. 143 68

We investigated the extravasation of serum albumin using immunohistochemistry in three different conditions, i.e., infarction, selective neuronal death and selective loss of presynaptic terminals following cerebral ischemia in gerbils. In selective neuronal death, which is typically found in the CA1 neurons of the hippocampus after 5-min bilateral cerebral ischemia, selective damage of postsynaptic components with intact presynaptic sites was demonstrated by immunohistochemical examination for microtubule-associated protein 2 and synapsin I, and albumin extravasation did not become apparent before postsynaptic structures were destroyed. In cerebral infarction, which was consistently observed in the thalamus after 15-min forebrain ischemia, massive albumin extravasation was visible early after ischemia due probably to the ischemic endothelial necrosis. In selective loss of presynaptic terminals, which was detected at the molecular layer of the dentate gyrus in the contralateral, nonischemic hippocampus after unilateral cerebral ischemia, immunoreaction for albumin was not visualized. Since endothelium and glial cells were intact in morphological aspects in selective damage of both pre- and postsynaptic sites, it was thought that extravasation was facilitated by the stimulation of endothelial cells and glial cells with unknown factors that were induced by the destruction of post- but not presynaptic elements.
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PMID:The characteristics of blood-brain barrier in three different conditions--infarction, selective neuronal death and selective loss of presynaptic terminals--following cerebral ischemia. 144 19


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