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Query: UMLS:C0086543 (cataract)
 29,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Twenty four patients, who had marked reduction of vision due to secondary-cataract developed after an ECCE, were treated by surgical cleaning of the posterior lens capsule. During this procedure globular secondary-cataract material was removed and collected for morphological examination by SEM and TEM. Fragments of various sizes and shapes, including some with a 'golf ball' structure, were seen; these closely resembled particles frequently found in cataractous lenses. In addition, in 18 patients micro-organisms were found: rod-shaped bacteria, cocci, and in 2 cases yeasts. These findings were the more remarkable because these were clinically quiet eyes with no signs of intra-ocular inflammation and cultures have been persistently negative. We imagine that these bacteria must have entered the eye during the cataract extraction and have settled there without causing an infection.
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PMID:(An)aerobic bacteria found in secondary-cataract material. A SEM/TEM study. 130 16

Lens tissue from a Morgagni cataract was examined by SEM and TEM. For SEM, after prefixation with glutaraldehyde and postfixation with the tannic acid/arginine/OsO4 non-coating (TAO) technique, and for TEM, after prefixation with glutaraldehyde, postfixation with OsO4/K4Fe(CN)6 and poststaining with uranyl acetate/lead citrate. The TAO technique seems to be a particularly suitable postfixation method for the SEM investigation of cataract tissue because of the presence of the protein structures present. The cortical region showed areas of radially, instead of concentrically, arranged lens fibres, degenerated lens fibres with holes (vacuoles), broken ball and socket connections between the lens fibres, and oval or spherical structures varying in size from 0.5-20 microns, the largest resembling a golfball, arising from the cytoplasm of degenerating lens fibres. The smallest, 0.2-0.5 microns, appear to have been expelled from the furrowed lens epithelium.
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PMID:Study of the substructure of the Morgagni and Brunescens cataract with the TAO non-coating technique. Part 1: Morgagni cataract. 130 20

Lens tissue from a Brunescens cataract was prepared for SEM study by prefixation with glutaraldehyde and postfixation with the tannic acid/arginine/OsO4 combination; for TEM study the material was prefixed with glutaraldehyde, postfixed with OsO4/K4Fe(CN)6 and poststained with uranyl acetate/lead citrate. At low magnification, in contrast to the Morgagni cataract, no difference could be seen between the lens fibres in the cortical and nuclear areas. Morphologically, the destruction of the ball and socket system and the development of holes and spherical structures was striking. The latter appeared to have a thin coating and, after fracture, were either empty or showed remnants of material resembling membranes. In sections of the cataractous material, larger vacuoles containing smaller spheres were indistinctly visible.
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PMID:Study of the substructure of the Morgagni and Brunescens cataract with the TAO non-coating technique. Part 2: Brunescens cataract. 130 21

Lens capsules of patients of advanced age, obtained after extracapsular cataract surgery, were carefully prepared for a combined LM, TEM and SEM investigation, after preliminary washing and mounting onto a holder in a buffer solution. After pre-fixation with GA, samples were postfixed for LM/TEM and OsO4/K4Fe)CN)6 and stained with toluidine-blue/basic fuchsin for LM and with uranyl acetate/lead citrate for TEM; for SEM the GA-pre-fixed samples were post-fixed by the Tannin Arginine-OsO4 non-coating technique. At LM-level discrimination between healthy and degenerating cells was possible after toluidine staining. At SEM-level protrusion of the cell nucleus and fibrillation and blebbing of the cell membrane as the result of capsular degeneration could be observed with the TAO-method. At TEM-level protrusion of the cell nucleus, degeneration of the cytoplasm, ballooning of the mitochondria, the presence of microfilaments and the occurrence of vacuoles were visible as the result of capsular degeneration on cataract formation.
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PMID:Morphological aspects of human lens capsules. A comparative LM, SEM and TEM examination. 172 16

Collagen shields have been studied in the enhancement of the initial healing of epithelial defects, as an adjunct in the treatment of dry eye, and as a reservoir and delivery system for topical ocular medications. The authors used collagen shields to collect information on the numbers and types of free cells populating the normal and postoperative ocular surface. In addition, correlative microscopic techniques were used to study details of the mechanisms responsible for the dissolution of the shields when applied to the human eye. Collagen shields were applied as a bandage lens on the eyes of patients who underwent extracapsular cataract extraction (n = 10) or penetrating keratoplasty (n = 10) and on normal volunteers (n = 10). The shields were collected at the 1-day postoperative examination and fixed in aldehyde mixtures. Specimens then were processed for correlative light (LM), transmission (TEM), and scanning (SEM) microscopy. Cell accumulation was shown by SEM on both anterior and posterior shield surfaces. Cell adherence occurred primarily on the posterior shield periphery for approximately 2 mm, with the central zone relatively clean. Both LM and TEM evaluation revealed cell counts ranging from 0.066 cells/10(4) microns2 (standard deviation, +/- 0.256) in healthy eyes compared with shields placed on postoperative eyes (194.25 +/- 7.32 cells/10(4) microns2). Various correlative microscopy techniques revealed that most cells were polymorphonuclear leukocytes with a low number of other hematogenous (lymphocytes and monocytes) and exfoliated epithelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Collagen shields as a vehicle for collecting and studying migratory cells on human corneas. 174 Mar 59

Cataract lenses from patients of advanced age were processed for SEM by standard pre-fixation followed by treatment by the Tannin-Arginine-Osmium-tetroxide (TAO) method and critical point drying, and for TEM by standard pre-fixation followed by vibratomation, standard post-fixation, ultramicrotome sectioning and staining with uranyl acetate/lead citrate. Secondary cataract material was brought onto a Millipore filter, fixed by standard methods, dried in air and sputter-coated with Au. Both SEM and TEM images revealed degeneration processes in lensfibre material, such as swelling of the lensfibre, protrusion of the cytoplasm, fibrillation of the cell membrane, loss of the nucleus, spherical bodies of various sizes between 0.5-1.5 microns, sometimes surrounded by a (double) membrane with different contrast but without cellular evidence, and small and large vacuoles partly filled with granular material both in and at the periphery of the lensfibre-body. The secondary cataract material on the Millipore filter revealed erythrocytes and more or less spherical bodies with high contrast, measuring between 0.5-1.5 microns, often referred to as Elschnig's pearls, besides non-definable organic material. The SEM and TEM micrographs of the cataract lens material strongly suggest that the spherical bodies with sizes of approximately 0.5-1.5 micrometer and high contrast without cellular evidence, are similar to the more or less spherical bodies found in the secondary cataract material on the filter, referred to as Elschnig's pearls.
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PMID:A combined scanning and transmission electronmicroscopic investigation of human (secondary) cataract material. 179 Jul 55

Rat lenses incubated in tissue culture medium (M 199) maintain their transparency for a long period of time. The soluble corticosteroid, solumedrol (methyl prednisolone sodium succinate) was added to the medium, at concentrations including the range expected during rejection episodes following organ transplantation (3.8 X 10(-9) M-3.8 X 10(-6) M). At the lowest level used (3.8 X 10(-9) M), five lenses of 12 became opaque following a 48 hr incubation, while at higher concentrations of solumedrol almost all lenses developed opacities. Addition of vitamin E to the medium resulted in partial prevention of the cataract as judged by the smaller proportion of lenses becoming opaque. Examination of the lenses by scanning and transmission electron microscopy (SEM and TEM, respectively), indicated that in untreated lenses the initial location of the cataract is at the anterior pole of the lens where a deepening area of degeneration formed, followed by a uniform subcapsular layer of degeneration spreading over the remainder of the lens. Damage at this location is not typical of most in vitro cortical cataracts. In the presence of vitamin E the extent of damage was less, involving, initially, an equatorial wedge of globular degeneration and spreading anteriorly and posteriorly in a thinner subcapsular layer. This type of damage was more typical of that seen previously for cataracts induced by cytochalasin D, elevated glucose and hygromycin B.
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PMID:Modeling cortical cataractogenesis. V. Steroid cataracts induced by solumedrol partially prevented by vitamin E in vitro. 634

Ultraviolet radiation in the near range (UVA) causes lens opacification and disrupts the actin cytoskeleton in rabbit and gray squirrel lenses. Changes were noted using transmission electron microscopy of tangential sections and rhodaminephalloidin fluorescence microscopy of epithelial whole mounts of irradiated and unirradiated lenses, and corresponded with gross cataract formation. Irradiated lenses lacked microfilament polygonal arrays at the inner surface of the apical plasma membrane (i.e., in the cell pole next to the lens fibers) in lens epithelia of both species; a condensed actin bundle was present instead. This bundle, and scattered small actin clumps in the cytoplasm, were identified by immunogold TEM, using a specific antibody and a secondary antibody conjugated with colloidal gold. Similar techniques showed breakdown of tubulin and vimentin, but after longer intervals than for the breakdown of actin. Generalized cytologic damage was also present in epithelial cells, but not in the underlying cortical lens fibers. Damage began to occur after 4 hr of irradiation and became more severe with increased exposure. Shielded controls remained clear, had normal cytology and polygonal arrays, and no clumping of actin filaments.
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PMID:Near-UV radiation disrupts filamentous actin in lens epithelial cells. 822 6

Globular secondary cataract material, removed from 24 patients with ECCE after ophthalmic cleaning of the anterior capsule, were investigated with SEM and TEM. Besides spherical, somewhat oval shaped bodies of various shape and size comparable with those found in cataractous lenses, (an)aerobic bacteria and yeast cells were found in approximately 70% of the cases, all of them in eyes without intra-ocular inflammation. Probably these bacteria have been transferred from the conjunctiva during IOL.-implantation and were encapsulated without starting an inflammation.
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PMID:Microorganisms found in secondary cataract material of ECCE patients, a study with SEM and TEM. 839 43

The Morgagnian cataract lenses--pre-fixed with GA for SEM & TEM and post-fixed with tannic-acid-arginine-OsO4 for SEM and OsO4/K4Fe(CN)6 for TEM after staining with Ur-acetate/Pb-citrate--showed areas in the cortex with radial instead of concentric running lens fibres, degeneration of lens fibres with vacuoles and defected "ball & socket" connections. The presence of oval/spherical bodies of 0.5-20 microns was acknowledged, the largest of them having a golf-ball appearance and originating from the cytoplasm of the degenerating lens fibres; the smallest of them with an approximate size of 0.2-0.5 micron seemed to be formed by budding off from the microvilli of the furrowed lens epithelium. The Brunescens cataract lenses showed at low magnification no difference between lens fibres from the cortical area and the nucleus. The disintegration process of the lens fibres was observable as degradation of the ball & socket system and the existence of holes in the lens fibre body and emerging of spherical bodies from the cytoplasm. The globular structures seemed to be covered with a thin coating and were partly filled with a low density membranous-like material. In TEM-sections of the cataractous lens aterial vacuoles were visible consisting of a large number of smaller globules with a contents of low contrast low density membranous-like material, comparable with the globular structures seen in SEM.
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PMID:The Morgagnian and Brunescens cataract morphology studied with with SEM and TEM. 839 67


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