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)

The objective of the study was to characterize the morphologic and immunohistochemical features of lens epithelial-derived proliferative membranes from the anterior segment of canine globes. These features were correlated with those previously identified for diseases resulting from lens epithelial cell (LEC) proliferation including posterior capsular opacification, traumatic subcapsular cataract, and subcapsular plaques associated with hypermature cataracts. Sixteen canine globes were removed as a result of glaucoma or other complications following cataract extraction. Light microscopic and immunohistochemical analysis was performed on sections from formalin-fixed, paraffin-embedded globes. The tissues were stained with a variety of antibodies for cellular markers for LECs, growth factors or other cellular constituents relevant to cellular metaplasia and proliferation. The membranes were composed of monolayers or multilayers of spindle-shaped cells on the external surfaces of the anterior and posterior lens capsule, ciliary processes, iris leaflets, and iridocorneal angle, and they could be seen extending from an obvious monolayer of LEC within the capsular sac. Variably, scattered pigment cells, presumably of uveal origin, were concurrently present. Cellular components of the membranes stained positive for vimentin, transforming growth factor-beta, basic fibroblast growth factor, and smooth muscle actin. An amorphous eosinophilic extracellular matrix consisting predominately of collagen was associated with the membranes. Proliferative anterior segment membranes following cataract surgery were morphologically and immunohistochemically similar to cellular and matrix components of posterior capsular opacification and capsular plaques seen with hypermature cataracts, both of which result from metaplasia and proliferation of LEC. The presence of these LEC-derived membranes in association with secondary glaucoma suggests that exuberant proliferation of LEC outside the confines of the lens capsular sac may cause pathologic alterations in the eye following cataract surgery in the dog.
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PMID:Immunohistochemical analysis of lens epithelial-derived membranes following cataract extraction in the dog. 1139 59

Corneal opacity developed in an eye that had photorefractive keratectomy (PRK) with a 193 nm excimer laser 5 times over 3 years. Six months after the last PRK, a partial penetrating keratoplasty was performed. The cornea was stained and immunohistochemically evaluated for collagen types. Light microscopy showed thickening of epithelial layers, proliferation of subepithelial fibroblasts, and the absence of Bowman's membrane. Transmission electron microscopy showed irregular collagen lamellae and electron-dense deposits adjacent to keratocytes. The staining was positive for Alcian blue, and immunohistochemistry was positive for type IV and VI collagen. This case suggests that corneal opacity after repeated PRK is the result of deposits of type IV and VI collagen and acidic mucoprotein in the extracellular matrix.
J Cataract Refract Surg 2001 Jul
PMID:Corneal opacity after repeated photorefractive keratectomy. 1148 89

A 30-year-old patient with keratoconus, a stable refraction, and normal central corneal thickness had laser in situ keratomileusis (LASIK). Six months later, she had uneventful penetrating keratoplasty for keratectasia. The lamellar LASIK interface could not be clearly identified by light microscopy. The corneal wound site did not stain for methyl metalloproteinase 1 or 2. Both the corneal flap undersurface and the stromal bed were devoid of interconnections and cells. Throughout the lamellar incision, including the laser-ablated zone, the surface was smooth on scanning electron microscopy. The collagen fibrils on both sides of the incision remained well aligned with one another, indicating good flap apposition. Under higher magnification transmission electron microscopy, some collagen fragments were found in the interface, especially adjacent to the hinge. The diameter of the collagen fibrils along the lamellar wound were identical to those farther from the incision. The absence of bridging collagen fibrils and cells between the flap undersurface and the stromal bed confirms the clinically known lack of wound repair at the interface and explains the easy separation of the flap from the stromal bed months after LASIK and the possible formation of an interface fluid pocket.
J Cataract Refract Surg 2001 Aug
PMID:Ultrastructure of the lamellar corneal wound after laser in situ keratomileusis in human eye. 1152 8

Histopathologic examination and immunohistochemistry for collagen type V were performed on residual anterior lens capsules of vitrectomized eyes (2 patients) that had been tamponaded with silicone oil. Many spaces, presumably occupied by oil droplets, were observed in connective tissue accumulations beneath the capsules. Immunoreactivity in the extracellular matrix for collagen type V was most marked adjacent to these spaces. These silicone droplets may delay capsule healing as collagen type V indicates immature connective tissue.
J Cataract Refract Surg 2002 Feb
PMID:Histopathology of anterior lens capsules in vitrectomized eyes with tamponade by silicone oil. 1182 Dec 26

A total of 132 patients were observed after cataract extraction with implantation of T-26 polymethacrylate and RSP-1 collagen copolymer intraocular lenses. Factors of risk of postoperative exudative reaction and fibrosis of the posterior capsule were determined, which depend on previous ophthalmic diseases (glaucoma, uveitis, diabetic angioretinopathy) and concomitant acute and chronic diseases of other organs (bronchopulmonary system, collagenosis, cholecystitis). Moderate changes in the hemogram before surgery are worthy of note.
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PMID:[Risk factors for developing exudative reactions and fibrosis of the rear capsule after cataract extraction with implantation of an artificial lens]. 1184 2

Neodymium:YAG (Nd:YAG) goniopuncture is an efficient and safe treatment for low filtration through the trabeculo-Descemet's membrane after deep sclerectomy with a collagen implant (DSCI). The only reported complication of this procedure is choroidal detachment. However, we found an iris synechia in a patient whose intraocular pressure (IOP) was elevated again 1 month after Nd:YAG goniopuncture. Synechiolysis and peripheral iridectomy with Nd:YAG and argon lasers effectively removed the iris synechia, and IOP immediately dropped to the normal range. We believe that iris synechia is a potential complication that may cause elevated IOP after laser goniopuncture in patients having DSCI.
J Cataract Refract Surg 2002 May
PMID:Iris synechia after laser goniopuncture in a patient having deep sclerectomy with a collagen implant. 1197 77

The lens capsule, which is also called the lens basement membrane, is a specialized extracellular matrix produced anteriorly by the lens epithelium and posteriorly by newly differentiated fiber cells. SPARC (secreted protein, acidic and rich in cysteine) is a matricellular glycoprotein that regulates cell-cell and cell-matrix interactions, cellular proliferation and differentiation, and the expression of genes encoding extracellular matrix components. SPARC-null mice exhibit lens opacity 1 month after birth and mature cataract and capsular rupture at 5-7 months. In this study, we report disruption of the structural integrity of the lens capsule in mice lacking SPARC. The major structural protein of basement membrane, collagen type IV, in the lens capsule was substantially altered in the absence of SPARC. The lens cells immediately beneath the capsule showed aberrant morphology, with numerous protrusions into the lens basement membrane. SPARC-null lenses at 1 month of age exhibited an increased penetration of dye or radioactive tracer through the capsule, as well as a higher content of water than their wild-type counterparts. Moreover, SPARC-null fibers exhibited swelling as early as 1 month of age; by 3 months, all the fiber cells appeared swollen to a marked degree. By contrast, the absence of SPARC had no apparent morphological effect on the early stages of lens formation, cell proliferation or fiber cell differentiation. Degradation of crystallins and MIP 26, or changes in the levels of these proteins, were not detected. These results underscore the importance of the capsular extracellular matrix in the maintenance of lens transparency and indicate that SPARC participates in the synthesis, assembly and/or stabilization of the lens basement membrane.
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PMID:Alterations in the lens capsule contribute to cataractogenesis in SPARC-null mice. 1207 65

Cataract formation is a deleterious side effect of some hormone therapies, thus, it is important to understand how hormones regulate lens basement structure and function. We have examined the effects of dexamethasone (DEX) on the regulation of Secreted Protein Acidic and Rich in Cysteines (SPARC), fibronectin (FN), and collagen IV (CN IV). To radiolabel newly synthesized proteins, cultured monolayers of bovine anterior lens capsule epithelial (ALCE) cells were pulsed with [(3)H] proline. To identify proteins, an immunofluorescent technique, immunoprecipitation with specific antibodies, and electrophoretic separation on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were used. DEX increased production of total proteins, whereas it specifically decreased synthesis of FN and CN IV. A decrease in FN and CN IV synthesis by DEX in ALCE cells may decrease adhesion of lens epithelium to the basement membrane (BM), which may in turn cause pathogenesis. Messenger RNAs were identified by Northern blot analyses using specific DNA probes. Treatment of lens epithelial cells with DEX causes a 100-150% up-regulation of SPARC mRNA in a concentration-dependent fashion. The increase in the expression of FN mRNA by DEX was in a dose-response fashion and varied from 50-600%. A 24-hour treatment with DEX (10(-6)M) increased CN IV mRNA levels to 386% over baseline levels. Thus showing a differential upregulation by DEX of mRNAs of SPARC, FN, and CN IV. Results of nuclear run-on transcription assays indicate that regulation of RNAs by DEX may occur, in part, at the transcriptional level. The aberrant expression of lens basement membrane proteins by DEX may contribute to abnormal lens cell function and ultimately to anterior subcapsular cataract.
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PMID:Expression and regulation of SPARC, fibronectin, and collagen IV by dexamethasone in lens epithelial cells. 1246 89

An 80-year-old male patient experienced recently diagnosed swelling of the limbal conjunctiva. In his clinical history were found cataract surgery on the right eye 3 months before, chronic open angle glaucoma effectively treated by local eye drops, treated systemic hypertension and hypercholesterolemia. On ophthalmic examination, a conjunctival mass was present in the inferior lateral conjunctival quadrant next to the limbus, with numerous vessels visible at its top. Treatment with topical corticosteroids failed to obtain regression, but decreased the local inflammatory signs. The persistence of the mass led to its surgical excision under local anesthesia. Histopathology found a subepithelial accumulation of modified collagen bundles typical of elastotic degeneration. Capillary vessels were seen in the superficial subepithelial area, attesting to the high degree of vascularization observed clinically. The final diagnosis was a pinguecula, which was not exactly located on the horizontal meridian area as it is usual.
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PMID:[Inflammation of an ectopic pinguecula]. 1251 50

Vitreoretinal pathologies remain the significant leading cause of blindness, after cataract, throughout the world. Biomaterials as a whole, and vitreous substitutes in particular, have had a major role to play in vitreoretinal surgery. History has witnessed the advent of vitreous substitutes from collagen and hyaluronic acid to gases, silicone oils and perfluorocarbon liquids and now to polymer hydrogels. Such a long list only underscores the fact that we have been found wanting in our quest for an ideal vitreous substitute. This review focuses on the merits and demerits of various vitreous substitutes, which have been tried to date, clinical as well as experimental. The properties required of an ideal substitute and the performance of the vitreous substitutes with respect to these criteria have been described. Finally, the concluding note dwells on the future directions for biomaterial research in the posterior segment of the eye and undermines the role of tissue engineering in vitreoretinal regeneration.
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PMID:Artificial vitreous replacements. 1265 23


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