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)

A patient with decreased visual acuity had small, glistening white particles that were scattered over both posterior poles. Monochromatic fundus photography revealed ghost vessels and intraluminal particulate matter in small retinal vessels. Fluorescein angiography demonstrated nonperfusion of small arterioles and macular capillaries. The patient admitted to multiple intravenous injections of crushed methylphenidate (Ritalin) hydrochloride tablets, which contain talc 18 months prior to examination. To our knowledge, visual loss and irreversible macular ischemia from talc emboli have not been previously documented.
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PMID:Talc emboli and macular ischemia in intravenous drug abuse. 44 39

Since the number of cases for each of the conditions in our study was small, only preliminary conclusions can be made; in order to establish the fluorescein pattern of each of these peripheral retinal lesions, additional studies will be required. The following summarizes our preliminary observations. 1. Areas of retinal white-with-pressure or without and peripheral retinal cystoid degeneration did not reveal remarkable fluorescein angiographic findings. One exception was in an area of pigment epithelial disturbance characterized by atrophy and proliferation, which showed a "window and masking" effect of choroidal fluorescence. 2. Fluorescein angiography of areas of the fundus with lattice retinal degeneration showed little or no findings in early or mild cases. In severe or advanced cases, the affected retina revealed poor or absent perfusion caused by vascular occlusion. The retinal and choroidal circulation was devoid of fluorescein leakage. Advanced lesions displayed choroidal hypofluorescence in areas of pigment proliferation and hyperfluorescence in areas of pigment atrophy. 3. In advanced cases, occlusive vascular changes over areas of acquired retinoschisis were observed. There was intraretinal leakage of the dye from deep capillaries and pooling of the dye in cystic cavities near the margin of the retinoschisis. 4. There was no perfusion of the choroid and retina in the area of the hole and in the retina surrounding it. This finding suggests choroidal and retinal ischemia in the pathogenesis of a retinal hole. 5. Fluorescein angiography of retinal tears revealed fluorescein leakage along the edge of the tear and absent perfusion of the retinal flap. The retinal and choroidal circulation-around the tear was otherwise unremarkable. The choroidal fluorescein underlying the retinal flap was not visible, perhaps because it was masked by the retinal flap. 6. Our fluorescein angiographic findings in cases of rhegmatogenous retinal detachment confirmed those of others [7, 8, 10]. Transit of fluorescein through the retinal circulation was sluggish. The retinal capillaries were dilated. 7. In cases of rhegmatogenous retinal detachment which had become reattached surgically, areas treated with diathermy or cryoapplications showed absent or diminished choroidal and retinal perfusion. Leakage of the fluorescein from capillaries in the optic disc and retina in the posterior pole was sometimes persistent several months postoperatively.
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PMID:Fluorescein angiography of degenerative lesions of the peripheral fundus and rhegmatogenous retinal detachment. 93 73

Neutrophils (PMN) have been implicated as mediators of the "no-reflow" phenomenon seen in skeletal muscle during reperfusion after ischemia. In order to evaluate the PMN contribution to the changes seen in the microcirculation of skeletal muscle after ischemia, we evaluated PMN velocity using in vivo microscopy in a rat model. After the induction of anesthesia, the right iliac and femoral arteries were isolated. The right anterior tibialis muscle was exposed in situ, covered with a plexiglass disc, and perfused with Kreb's solution. Fluorescein-labeled bovine albumin was given intravenously, which identified the capillaries under microscopic magnification as viewed on the video screen. Acridine orange was then administered intravenously, which selectively fluoresced the PMN. The right iliac and femoral arteries were clamped for ischemia intervals of 5, 10, 15, 20, 25, and 30 min. Acridine orange was given immediately after the arteries were unclamped, after 30 min of reperfusion and after 60 min of reperfusion. PMN velocity was determined by the distance traveled by the PMN over time using the videotape and frame-by-frame review. Results demonstrated no change in PMN velocity (mm/sec) after 5 min of ischemia. After 10, 15, and 20 min of ischemia, PMN velocity initially slowed and then recovered, which was not statistically significant. After 25 min of ischemia, PMN velocity decreased significantly, which persisted (P < 0.05 compared to 5-min ischemia by ANOVA). No flow was seen after 30 min of ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:In vivo microscopy of rat skeletal muscle after ischemia using labelled neutrophils (PMN). 149 88

Subretinal or preretinal neovascularisation may be occasionally observed during the evolution of certain forms of uveitis. Subretinal neovascularisation commonly begins at the level of the chorioretinal uveitic scars. Consequently, the alteration of the retinal pigment epithelium-Bruch's membrane-choriocapillaris complex is the apparent cause. Laser photocoagulation of the neovascular front, when indicated, is the treatment of choice. In contrast, preretinal neovascularisation is observed at the active stage of uveitis. Fluorescein angiography findings suggest that it is probably correlated with the importance of inflammation since in most of the cases there is no retinal ischemia. Therefore, in order to obtain a regression of the neovascular tufts the treatment should be directed against the inflammatory process. In this study the authors report five cases of subretinal neovascularisation which developed at the level of chorioretinal post-inflammatory scars and one case of papillary neovascularisation which occurred during the active stage of an unilateral intermediate uveitis and in which new vessels regressed completely following systemic steroid treatment.
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PMID:[Uveitis complicating posterior segment neovascularization. Six cases]. 161 5

This study of the postischemic events in the hamster cheek pouch showed that there is an increase in number of leukocytes adhering to the venular endothelium after reperfusion. It also showed that the stable prostacyclin analogue Iloprost could counteract both the postischemic increase in leukocyte adhesion and the postischemic increase in vascular permeability to macromolecules. The hamsters were anesthetized and the cheek pouch was everted and prepared for intravital microscopy. Temporary ischemia (30 min) was obtained using an expandable cuff placed around the proximal part of the cheek pouch. Fluorescein labelled dextran (FITC-dextran, Mw 150,000) was used as a tracer of macromolecular leakage from the postcapillary venules. Iloprost, given either topically (0.1 nM) or as an intravenous infusion (40 ng/kg/min), reduced the postischemic permeability increase (P less than 0.05) but did not affect the hemodynamics or the permeability response induced by histamine. It is proposed that these effects could be due to inhibition of leukocyte activation by Iloprost, indicating that these cells could play a role in the permeability increase during reperfusion after ischemia.
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PMID:Modification of postischemic increase of leukocyte adhesion and vascular permeability in the hamster by Iloprost. 170 55

Drainage-retinotomies and relaxing retinectomies are helpful techniques in extreme vitreoretinal surgery. They have become established as a surgical instrument, but their possible pathophysiologic effects on the retina, pigment epithelium and choroid have not been investigated as yet. 30 Patients with retinotomies or retinectomies after vitrectomy with silicone oil filling for advanced proliferative vitreoretinopathy were studied angiographically. Fluorescein angiographic findings revealed 1. a predominant effect of endophotocoagulation in the area of the retinotomy/retinectomy with occlusion of the choriocapillaris and hyperpigmentation and window effects of the retinal pigment epithelium, but sometimes there was a localized traction effect with retinal and choroidal folds, 2. that retinal perfusion is unaffected in untreated and coagulated areas without evidence for a breakdown of the blood-retina-barrier or retinal ischemia, 3. an intact blood-retinal-barrier in areas of uncovered retinal pigment epithelium, 4. no evidence for significant reproliferations in the areas of retinotomies and retinectomies, 5. choroidal neovascular membranes which may occur postoperatively at the retinotomy site probably as a complication for intraoperative injury of Bruch's membrane, 6. a cystoid macular edema, an optic atrophy, pigment-fallout, depigmented tracks and choroidal folds as unspecific findings post retinal detachment surgery. The angiographic data support the clinical impression, that retinotomies and retinectomies performed in otherwise untreatable cases cause no significant damage in the attached retina.
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PMID:[Fluorescein angiography findings after retinotomy and retinectomy]. 175 69

The authors present a case of severe retinal ischemia associated with Dibekacin intraocular injection. This aminoglycoside was used, at an inadvertent dose, for the treatment of a postoperative endophthalmitis. The prominent finding at ocular ophthalmoscopy was oedematous retina with hemorrhages in the macular area. Fluorescein angiography revealed severe retinal vascular non perfusion. The eye subsequently developed neovascular glaucoma. Precautions are necessary to prevent such a catastrophic event; the injectable solution must be prepared on the surgical field, the injection should be performed slowly in the anterior vitreous without exceeding 0.2 mg when Gentamicin is used.
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PMID:[Retinal toxicity caused by intravitreous injection of an aminoglycoside. Apropos of a case]. 179 Dec 80

To elucidate parameters diagnostic of chronic ischemia, the fluorescence of skin on the foot, leg, arm, and forehead of six chronically ischemic patients and six normal subjects injected with fluorescein was measured serially using a surface-measurement fluorometer (dermofluorometer). Simultaneously collected plasma samples were assayed spectrofluorometrically for unmetabolized fluorescein. The time courses of plasma fluorescein content and dermofluorometer readings were jointly analyzed by combining a standard pharmacokinetic model, a model predicting skin site from plasma concentrations of fluorescein, and a model predicting the dermofluorometer response to those skin concentrations. Fluorescein plasma clearance (0.22 +/- 0.06 versus 0.46 +/- 0.20 L/h/kg) in ischemic patients was only half, and half-life was double (2.4 +/- 1.0 versus 1.3 +/- 0.3 h) those in normal subjects, with volume of distribution (Vdss = 0.46 L/kg) being similar. Despite the ischemia diagnosis for all patients involving claudication of the lower extremities, patients could be distinguished statistically from normal subjects on the basis of fluorescence readings taken on the arm, but not those using the foot or leg. The rate constant describing flux of fluorescein from the arm skin site in patients was only half that in normal subjects, and the peak reading on the arm occurred at 42 +/- 14 min after fluorescein injection in patients, but at only 15 +/- 6 min in normal subjects. Lack of discrimination between subject groups via leg and foot readings may be due to several physiologic and/or experimental factors, including the need to take skin surface readings much earlier than previously recognized.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Relationship between skin fluorescence and blood flow in normal and in chronically ischemic subjects dosed with fluorescein. 194 58

Strabismus surgery results in the permanent interruption of anterior ciliary blood flow, predisposing the eye to anterior segment ischemia (ASI). A primate model was used to assess the effectiveness of a new muscle-scleral tuck for preserving anterior ciliary artery circulation. The model consisted of removing 3 rectus muscles from both eyes of 2 rhesus monkeys, then performing a tuck on the inferior rectus (IR) right eye while leaving the left IR as a control. Four weeks later, a modified tuck was performed on the virgin left IR. Fluorescein iris angiograms of both eyes were obtained, and preoperative angiograms at 5-15 sec. showed normal 360 degrees perfusion. Postoperative follow-up angiograms showed segmental superior temporal filling defects and preservation of perfusion in the distribution of the IR. Comparison of fellow eyes tucked vs control IR showed no difference in the filling pattern in both monkeys. Comparison of the same eye before and after tuck also showed essentially the same filling pattern in all 4 eyes with preservation of inferior circulation. Our conclusion is that the modified tuck preserves the anterior ciliary blood flow and may be useful as a muscle-strengthening procedure in patients predisposed to developing ASI.
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PMID:Effect of a modified rectus tuck on anterior ciliary artery perfusion. 194 98

Exudative retinal detachments occur in a variety of retinal and choroidal diseases. We created serous retinal detachment in the cat eye by means of photodynamic injury produced by activation of intravascular rose bengal using filtered, focused light (550 nm). Fluorescein angiography later revealed focal retinal and choroidal vascular occlusion surrounded by a larger area of leakage through the pigment epithelium. Serous retinal detachments occurred rapidly, gradually enlarged over the next 3 days, and resolved in all eyes after 14 to 21 days. Histopathologic and ultrastructural features of early lesions included the accumulation of proteinaceous fluid in the subretinal space, pigment epithelial cell damage, and localized occlusion of retinal vessels and the choriocapillaris. Later changes consisted of limited regeneration of the retina and portions of the tapetum. In several respects, these experimental detachments resemble the serous retinal detachments associated with choroidal ischemia in humans, and may serve as a useful model in the study of choroidal microvascular hypoperfusion.
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PMID:Exudative retinal detachment after photodynamic injury. 198 30


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