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

Anterior segment ischemia changes can occur without detachment of any muscles. The most common cause of such ischemic changes of the anterior segment is the removal of too many rectus muscles in one operation. Twenty dog eyes and eight monkey eyes were subjected to the disinsertion and detachment of various combinations of extraocular muscles. They were sacrificed at intervals from 30 to 90 days. During the observation period, they were observed for gross and slit lamp changes. The enucleated eyes were studied microscopically for signs of ischemic and necrotic changes. Two patients who were studied, observed, and treated for anterior segment ischemia following muscle surgery are described. The changes which occur after muscle surgery are extensive and include corneal edema, cataract, chemosis, corneal changes, decreases in intraocular pressure, decreases in outflow or glaucoma and frank necrosis. The variables which lead to this reaction is described in detail. Also, some unanswered queries, such as the duration of the reaction and the time interval of the reaction after multiple muscle surgeries, are discussed.
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PMID:Production of anterior segment ischemia. 10 21

The effects of ischemia on the canine myocardial (Na+ + K+)-ATPase complex were examined in terms of alterations in cardiac glycoside binding and enzymatic activity. Ability of the myocardial cell to bind tritiated ouabain in vivo was assessed after 1, 2, and 6 h of coronary occlusion followed by 45 min of reperfusion, and correlated with measurements of in vitro (Na+ + K+)-ATPase activity and in vitro [3H]ouabain binding after similar periods of ischemia. Regional blood flow alterations during occlusion and reperfusion were simultaneously determined utilizing 15 mum radioactive microspheres to determine the degree to which altered binding of ouabain might be flow related. Anterior wall infarction was produced in 34 dogs by snaring of confluent branches of the left coronary system. Epicardial electrograms delineated ischemic and border zone areas. Coronary reperfusion after 2 and 6 h of occlusion was associated with impaired reflow of blood and markedly impaired uptake of [3H]ouabain in ischemic myocardium. In both groups, in vivo [3H]ouabain binding by ischemic tissue was reduced out of proportion to the reduction in flow. Despite near-complete restoration of flow in seven dogs occluded for 1 h and reperfused, [3H]ouabain remained significantly reduced to 58 +/- 9% of nonischemic uptake in subendocardial layers of the central zone of ischemia. Thus, when coronary flow was restored to areas of myocardium rendered acutely ischemia for 1 or more hours, ischemic zones demonstrated progressively diminished ability to bind ouabain. To determine whether ischemia-induced alteration in myocardial (Na+ + K+)-ATPase might underlie these changes, (Na+ + K+)-ATPase activity and [3H]ouabain binding were measured in microsomal fractions from ischemic myocardium after 1, 2, and 6 h of coronary occlusion. In animals occluded for 6 h, (Na+ + K+)-ATPase activity was significantly reduced by 40% in epicardial and by 35% in endocardial layers compared with nonischemic myocardium. Comparable reductions in in vitro [3H]ouabain binding were also demonstrated. Reperfusion for 45 min after occlusion for 6 h resulted in no significant restoration of enzyme activity when compared to the nonreperfused animals. In six animals occluded for 2 h, a time at which myocardial creatine phosphokinase activity remains unchanged, (Na+ + K+)-ATPase activity was reduced by 25% compared with nonischemic enzyme activity. In five dogs occluded for 1 h, (Na+ + K+)-ATPase activity in ischemic myocardium was unchanged from control levels. We conclude that reduced regional myocardial blood flow, local alterations in cellular milieu, and altered glycoside-binding properties of (Na+ + K+)-ATPase all participate in the reduction of cardiac glycoside binding observed after reperfusion of ischemic myocardium. In addition, after 2 or more hours of severe ischemia, myocardial (Na+ + K+)-ATPase catalytic activity is significantly reduced despite incubation in the presence of optimal substrate concentrations.
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PMID:Ischemia-induced alterations in myocardial (Na+ + K+)-ATPase and cardiac glycoside binding. 13 Mar 83

Anterior segment ischemic changes can occur without detachment of any muscles. The most common cause of such ischemic changes of the anterior segment is the removal of too many rectus muscles in one operation. Twenty dog eyes and eight monkey eyes were subjected to the disinsertion and detachment of various combinations of extraocular muscles. The dogs were sacrificed at intervals from 30 to 90 days. During the observation period, they were observed for gross and slit-lamp changes. The enucleated eyes were studied microscopically for signs of ischemic and necrotic changes. Two patients who were studied, observed, and treated for anterior segment ischemia following muscle surgery are described. The changes which occur after extraocular muscle surgery are extensive and include corneal edema, cataract, chemosis, corneal changes, decreases in intraocular pressure, decreases in outflow or glaucoma, and frank necrosis. The variables which lead to this reaction are described in detail. Also, some unanswered queries, such as the duration of the reaction and the time interval of the reaction after multiple muscle operations are discussed.
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PMID:Production of anterior segment ischemia. 41 49

Anterior segment ischemia is perhaps the most rare ocular manifestation of temporal arteritis. We described a 73-year-old woman with anterior segment ischemia in the course of temporal arteritis. Early recognition of the syndrome and treatment with high doses of steroids led to visual recovery in the involved eye.
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PMID:Anterior segment ischemia in temporal arteritis. 59 6

A constricting silicone band was added to 13% of local sponge buckle operations in this series. The purpose was to relieve circumferential traction or to maintain a high buckle. The inclusion of a cerclage did not require drainage of subretinal fluid. The rate of reattachment without drainage (42 of 50 detachments) is comparable to what might be expected if the subretinal fluid had been drained. Constriction was controlled and limited to between 10% and 25% of the circumference of the eye. Anterior segment ischemia requiring relaxation of the band occurred in two patients; scleral erosion did not occur.
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PMID:Limits of constriction in the treatment of retinal detachment. 96 57

An encircling constriction procedure has been added to the localized indentation operation. The inclusion of a cerclage does not in itself require drainage of subretinal fluid. Experiments were done in an animal model to determine the amount of constriction that would be tolerated by the eye without provoking a significant incidence of anterior segment ischemia or scleral erosion. From these experiments it was projected that the human eye might withstand a reduction in band length between 10 and 20% of its circumference without important morbidity. 119 patients were operated upon over six years with a cerclage constricted within these limits. Anterior segment ischemia occurred twice, scleral erosion not at all.
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PMID:Encircling operations without drainage of subretinal fluid. 116 Aug 99

Anterior segment ischemia occurred in a 66-year-old patient following recession of one medial rectus muscle combined with lateral rectus muscle union to the vertical rectus muscles (Jensen procedure). The mechanism of this complication is explained as inadvertent strangulation of the anterior ciliary arteries during tying of the split lateral rectus to the temporal aspects of the vertical rectus muscles. Special efforts to preserve the integrity of anterior ciliary arteries in those portions of the vertical rectus muscles not involved in the muscle union should be made to avoid this complication.
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PMID:Anterior segment ischemia following the Jensen procedure. 126 60

We report a case of adult polymyositis with peculiar muscular pathology of innumerable muscle fiber necrosis and regeneration accentuated in the perifascicular area. A 51-year-old woman developed generalized weakness of the extremities, trunk and bulbar muscles subacutely for two months. Anterior tibial muscle biopsy showed numerous tube-like necrotic/regenerative muscle fibers predominantly in the perifascicular area. The diameters of the muscle fibers were smaller in the periphery of the fascicles. Small arteries at the center of the fascicles occasionally showed marked perivascular cuffing, although complement component C9 was negative in the vessel wall. The gradient of the diameters of necrosis/regeneration fibers was thought to have been caused by ischemia of the muscles, which persisted at the perifascicular area leading to recurrent necrosis and regeneration and gradually invaded towards the center of the fascicles. We designated this muscular pathology as perifascicular necrosis and regeneration, and regarded it was an acute severe form of the perifascicular ischemic lesions of myositis.
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PMID:[Perifascicular necrosis and regeneration in a case of adult polymyositis]. 191 31

The feasibility of the use of indium 111 oxine-labeled autologous leukocytes for the diagnosis of ischemic enterocolitis in vivo was examined in an experimental model of ischemia in dogs. A 30-cm segment of small intestine was devascularized by ligating the arteries and veins from the last arcade in 7 dogs. A sham operation was performed in 3 control dogs. 111In oxine-labeled autologous white blood cells were infused 3.5 hours after operation. Anterior and lateral nuclear scanning was performed at 6 and 24 hours postinfusion with a gamma camera equipped with a low-energy magnifying multihole collimator. The animals were killed after 24 hours. The gross and microscopic appearance of the bowel was evaluated. The radioactivity in the serial specimens of the bowel was measured. In vivo scans were positive (ie, increased uptake in the bowel loop) in all dogs with intestinal ischemia at 6 and 24 hours. No significant uptake was noted in control dogs. Rectilinear scan of the bowel removed at autopsy showed a correlation between the area of infarction and tracer accumulation. In addition, there was a progressive decrease in uptake of 111In oxine from the center of the ischemic lesions to the periphery. Forty percent of the total radioactivity was measured at the center of the lesion, whereas only 6.5% was present at 22.5 cm from the center. Thus the ratio between the ischemic and normal tissue was 10:1 (range, 6.5 to 16). These studies demonstrate that 111In oxine-labeled autologous white blood cells can be used for the diagnosis of ischemic enterocolitis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Indium 111 oxine-labeled leukocytes for early diagnosis of ischemic enterocolitis. 194 80

Anterior segment ischemia (ASI) is a dreaded complication of retinal detachment surgery particularly in patients with predisposing factors such as sickle cell disease. We report a case of ASI after scleral buckling in an otherwise healthy black patient with sickle cell trait. Conditions of relative hypoxia intraoperatively from either anesthesia or surgical manipulation may precipitate vasoocclusive phenomena in these normally asymptomatic patients. Since the incidence of sickle cell trait in the black population in the United States is 8.5%, we recommend these patients have a preoperative sickle test followed by hemoglobin electrophoresis with quantification if positive. The presence of sickle cell trait should alert the surgeon to the risk of ASI, and factors predisposing to hypoxia should be minimized when possible.
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PMID:Anterior segment ischemia: a complication of retinal detachment repair in a patient with sickle cell trait. 224 89


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