Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0086543 (cataract)
 29,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This thesis presents the results of a study of 384 eyes of 192 patients with a mean age of 39.1 years who presented with typical retinitis pigmentosa. The major findings are outlined below, together with suggested hypotheses: Cataract was found in 46.4% of the eyes. Among these, 93.6% showed posterior subcapsular opacification. The incidence of cataract increased with age. The vitreous degeneration that is characteristic of the RP syndrome and begins in childhood was described as showing dust-like, particulate matter throughout the gel; posterior vitreous separation; formation of a posterior matrix of coarse, white, interconnected strands and opacities; and final collapse of the residual gel. Ultrastructural studies of vitreous material from eight eyes revealed that the particles were isolated pigment granules and the coarse strands were composed of condensed collagen fibers. Notwithstanding the vitreous degeneration and prevalence of myopia in RP, neurosensory retinal breaks and/or rhegmatogenous detachment were found in only 7 (1.8%) of the 384 eyes studied. Premature separation of the vitreous from the retina, absence of lattice retinal degeneration, and perhaps a stronger than normal RPE-neurosensory retinal bond are thought to be possible protective factors. Rather than searching for a "toxin," elaborated by diseased retina, that causes vitreous degeneration and cataract formation, it is suggested that the ocular media be studied for an absence of moieties that are normally produced by healthy retina for vitreous and lens maintenance. The classic criteria for diagnosis of RP were met by 96.3% of eyes that showed retinal vascular attenuation and by 52.0% that showed pallor of the optic disc. Less frequent manifestations included solitary retinal hemorrhage, peripheral microaneurysms, telangiectasia, and fluorescein leakage at the macula and disc. Seven additional cases with a Coats'-like retinal detachment were added to the 14 already presented in the literature. Two of the seven had autosomal dominant RP, the first such cases reported. The vascular malformations and detachments were most often inferior. Unlike typical Coats' syndrome, the condition was usually bilateral, showed no sex preference, and appeared to affect older individuals.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Retinitis pigmentosa: clinical observations and correlations. 667 82

Light and electron microscopy and slitlamp microscopy were used to follow the development and partial repair of injury-induced cataract in the lens of the pigmented eye of the grey squirrel. These processes proceed in much the same way as in previously-studied albino rodents and rabbits in spite of invasion of the lens opacity by pigmented cells in the squirrel eye. Epithelial and capsular regeneration and lens fiber repair occur rapidly and apparently independently from the accumulation of pigmented cells, fibroblasts and collagen in the wound outside the lens epithelial layer. Using morphological criteria, some of the pigmented cells in the lens wound are identified as iris stromal melanocytes and pigmented epithelial cells; this is consonant with the slitlamp observations of streams of pigmented cells extending from the iris to the lens wound. The role, if any, of the pigmented cells in lens wound healing is unknown.
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PMID:Lens wound healing and cataractogenesis in a pigmented eye. 672 6

The ocular damage in young adult mice produced by purified Pseudomonas aeruginosa exotoxin A was microscopically characterized at 1 and 5 h and at 1, 3, 5, 7, 10, 14, and 21 days after toxin A challenge, using light, transmission, and scanning electron microscopic techniques. Similarly to previously described infection with viable organisms, toxin A killed both epithelial and endothelial cells and induced stromal cell swelling within 5 to 24 h after application onto the nonpenetrating wounded corneal surface. Other toxin-induced damage similar to the damage produced by infection with the viable bacteria was production of electron-dense particles within the corneal stroma, dispersal of undamaged collagen fibrils, and apparent loss of stromal proteoglycan ground substance. Toxin A damage differed from infection with the viable bacteria in essentially two ways. First, more purulent exudate and more polymorphonuclear neutrophilic leukocyte (PMN) infiltration of the corneal stroma were produced by infection with the viable organisms than by the toxin. Additionally, PMN did not appear within the toxin-treated corneas until 3 days after treatment, whereas in corneas infected with the viable organisms, PMN were numerous by 18 h. Secondly, toxin A produced cataract of the ocular lens, whereas infection with the viable organisms did not.
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PMID:Microscopic characterization of ocular damage produced by Pseudomonas aeruginosa toxin A. 680 Sep 50

Five patients with collagen vascular disease and keratoconjunctivitis sicca underwent cataract surgery and implantation of intraocular lenses. Postoperative development of corneal melting may have been potentiated by the use of topical 0.1% dexamethasone sodium phosphate alcohol and neomycin sulfate. Permanent visual loss occurred in two patients. Implant removal was necessary in two eyes. Medical management consisted of discontinuance of administration of steroids and antibiotics, as well as the addition of tear substitutes, cycloplegics, and pressure patching.
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PMID:Corneal melting with intraocular lenses. 689 39

In 26 patients (11 women and 15 men) with acute retinal vascular occlusion, the courses of spontaneous and collagen-induced thrombocyte aggregation were investigated 1 to 14 days (mean 6.8 +/- 4.8 days) after the onset of the symptoms and before the start of treatment, by means of the platelet aggregation test (PAT III) described by Breddin et al. (1975a). The results were compared with those of a control group consisting of 37 age-matched glaucoma and cataract patients (20 women and 17 men) with no vascular occlusions. Thrombocyte aggregation was high in 59.5% of the patients in the control group and 100% of the patients with retinal vascular occlusion. This would appear to show that pathological elevation of thrombocyte aggregation has considerable pathogenetic significance as an inducing factor of retinal vascular occlusion in the presence of concomitant arterial sclerosis and that treatment with inhibitors of thrombocyte aggregation would be appropriate.
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PMID:Retinal vascular occlusion and thrombocyte aggregation. 693 72

We studied a human cornea that was obtained at the time of penetrating keratoplasty four months after a keratophakia procedure and cataract extraction. We found endothelial cell loss with corneal edema, interface epithelial ingrowth, absence of keratocytes, and an abnormality in the collagen structure of the donor homograft (lenticule) and abnormal host keratocytes in the recipient lamellar (host) bed. We suspect that the cause of keratocyte and collagen injury was associated with the cryopreservation process. We recommend that if a combined cataract extraction and keratophakia procedure is contemplated, the lens extraction be performed in an intracapsular fashion if the keratophakia procedure has been completed or in an extracapsular fashion before the replacement of the donor lenticule and anterior part of the host cornea.
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PMID:The histopathology of a case of keratophakia. 703 2

A clinical method of measuring angular scatter from the human cornea is described. The method entails the use of a slit-lamp photometer with a pin-light attachment to control the angle of measurement. Corneal scatter and corneal thickness were measured in 93 normal subjects and 56 patients recently operated on for cataract. In the latter group, the surgically induced increase in corneal thickness was found to increase corneal scatter markedly, demonstrating the well-known dependence of scatter on corneal hydration. For the normal cornea, thickness and scatter were only insignificantly correlated. This finding was interpreted as evidence that the normal variation in corneal thickness is caused by a variation in mass content rather than in water content of the cornea. An increase in corneal scatter with age was demonstrated. Because this was seen at a constant corneal thickness, the mechanism was presumably that of age-related alterations in the latticelike organization of the collagen fibrils. These results suggest that clinical measurements of scatter may be used as a means to study hydration and ultrastructural characteristics of the human cornea in vivo.
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PMID:Light scattering from the human cornea. 708 24

Thirteen human lenses posterior subcapsular cataracts were examined by transmission electron microscopy to study the lens epithelial cells that characteristically migrate posteriorly in this disease. A sequence of histologic changes was identified from the equatorial region to the posterior pole. The cells became increasingly more active cytologically, culminating in lens-fiber-like formation or cell death at the posterior pole. Moderate amounts of extracellular granular and fibrillar material were produced, especially in the more advanced cases. No mature collagen was found. The liquefied posterior cataracts contained cellular debris from both degenerate lens fibers and necrotic migrating cells. The migrating lens cells thus contributed to the cataract by secretion, cytolysis, and probably by release of lysosomal enzymes. Bladder cells had many of the characteristics of lens fibers so that the term "abortive" or dysplastic lens fibers is appropriate for them.
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PMID:Human posterior subcapsular cataract. An ultrastructural study of the posteriorly migrating cells. 735 61

Fibrosis, contraction and opacification of the posterior lens capsule after extracapsular cataract extraction, is a frequent complication following cataract surgery. In these cases, cellular proliferation occurs along an intact posterior capsule. We report a case of fibrosis adjacent to the anterior lens capsule, where cellular proliferations and collagen production completely sealed the anterior capsulotomy three months after a routine extracapsular cataract extraction with implantation of a posterior chamber lens. The fibrosis led to contraction of the remainder of the anterior capsule, significantly reducing vision. Examination of the excised material by light and electron microscopy, and immunohistochemistry, revealed cells with features compatible with fibrocytes that did not stain positive for cytokeratin. The cells were situated in a dense collagen matrix. An anterior capsulotomy that is too small prevents sufficient removal of lens epithelium, and may be a risk factor for this complication.
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PMID:Fibrosis adjacent to the anterior lens capsule after extracapsular cataract extraction. 752 Apr 26

The Emory mouse is the best model for age-related cataract. In this work we compare the effects of feeding a control diet (C) with a diet restricted (R) by 40% relative to C animals. In the R animals, median lifespan was extended by 40%. The proportion of R mice with advanced cataract was lower than C mice as early as 5 months of age. The mean grade of cataract was lower in R animals, beginning at 11 months and continuing until the end of the study. Ascorbate levels in R plasma and liver were 41-56% of C animals. There was no difference between diet groups with respect to lens ascorbate. Aging was associated with a decrease in ascorbate in lenses and kidneys in C and R mice. By 22 months, R animals had 48% higher liver glutathione levels than C mice. Liver glutathione levels were maximal at 12 months. Plasma glucose levels were > 27% lower in R animals at 6.5 and 22 months, and there was a 14% increase in glucose levels upon aging for both diet groups. In R mice, glycohemoglobin levels were 51% lower and tail collagen breaktime was decreased by 40%, even in younger animals. Collagen breaktime increased > 360% upon aging for both diet groups. Rates of production of urinary oxo8dG and oxo8G were higher in R animals compared with C animals, and increased upon aging. C animals exhibited more cancer and dermatological lesions, but less tail tip necrosis and inflamed genitals than R mice. These data allow evaluation of several theories of aging.
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PMID:Dietary calorie restriction in the Emory mouse: effects on lifespan, eye lens cataract prevalence and progression, levels of ascorbate, glutathione, glucose, and glycohemoglobin, tail collagen breaktime, DNA and RNA oxidation, skin integrity, fecundity, and cancer. 754 Jul 4


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