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 new synthetic absorbable suture, Polyglactin 910, represents a significant step toward absorbable suture perfection. In 218 cataract surgical procedures, the performance of Polyglactin 910 was compared to that of Chromic Catgut and Chromic Collagen. The results obtained in this series of cases is the basis for this article. When compared to Chromic Catgut and Chromic Collagen, Polyglactin 910 consistently provided greater tensile strength, improved handling, significantly decreased tissue reaction, more batch-to-batch uniformity, superior wound tensile strength retention, and a predictable absorption rate that is virtually completed in 35 days. Both nonprotein and nonantigenic, Polyglactin 910 evoked less tissue reaction and proved more versatile and reliable than either of the other sutures.
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PMID:The evaluation of 7-0 Polyglactin 910 suture in cataract surgery. 110 25

Collagen type I was immobilized onto a poly(methyl methacrylate) (PMMA) plate by covalent bonding following surface modification by two methods. One method introduced amino groups by aminolysis with N-lithioethylenediamine (PMMA-NH2) and the other introduced carboxyl groups by graft copolymerization of acrylic acid (AAc) and acrylamide (AAm) (PMMA-COOH). Lens epithelial rabbit cells were cultured on the PMMA plate which was immobilized with collagen. Polygonal cells with a mosaic appearance were observed on the PMMA-COOH plate immobilized with collagen type I, whereas pleomorphic cells were present on the virgin PMMA and on the PMMA-NH2 plate immobilized with collagen type I. We concluded the PMMA-COOH plate immobilized with collagen type I provided a more comfortable atmosphere for lens epithelial cells, causing no metaplasia, than the other plates used in this cell culture model experiment.
J Cataract Refract Surg 1992 Jul
PMID:In vitro evaluation of biocompatibility of surface-modified poly(methyl methacrylate) plate with rabbit lens epithelial cells. 150 Oct 95

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

Collagen undergoes progressive browning with age and diabetes characterized by yellowing, fluorescence, and cross-linking. The present research was undertaken in order to investigate the nature of the collagen-linked fluorescence. Human collagen was exhaustively cleaved into peptides by enzymatic digestion. Upon purification, a highly fluorescent chromophore was identified and purified from old human collagen. Structure elucidation revealed the presence of an imidazo [4,5-b] pyridinium-type structure acting as a cross-link between arginine, lysine, and a pentose. This advanced glycosylation end-product and protein cross-link results from the reaction of pentoses with proteins and was named pentosidine. Further work indicated that long-term glycosylation of proteins with hexoses also leads to pentosidine formation through sugar fragmentation. The proposed mechanism of pentosidine formation involves the dehydration of the pentose-derived Amadori compound to form an intermediate which is attacked under base catalysis by the guanido group of arginine. The strict requirement for the Amadori rearrangement is uncertain. However, oxidation is definitely involved since pentosidine is not formed in the absence of oxygen. Five-carbon sugars contributing to pentosidine formation could be formed from larger sugars by oxidative fragmentation or from trioses, tetroses, and ketoses by condensation and/or reverse aldol reactions. Pentosidine increases exponentially in human skin at autopsy. Mean age-adjusted skin levels were significantly increased in subjects with uremia and especially in type 1 diabetics with uremia vs. controls. In skin biopsy, levels were significantly elevated in all diabetic (type 1) vs. control subjects. The highest degree of association was with the cumulative grade of diabetic complication (retinopathy, nephropathy, arterial stiffness, and joint stiffness). Pentosidine also forms in various proteins other than collagen, although to a much lesser extent. In blood, pentosidine is mainly associated with plasma proteins and is highly elevated during uremia. In the lens, it is associated with both water-soluble and -insoluble protein fractions and is especially elevated during brunescent cataract formation. The origin of pentosidine in vivo is uncertain. Evidence suggests that the pentoses are the most reactive sugars in pentosidine formation in vitro; however, the origin and importance of free pentoses in vivo, especially during the diabetic state, are not certain. Possible origins include hemolysis and/or a defect in the primary pentose metabolism.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Pentosidine: a molecular marker for the cumulative damage to proteins in diabetes, aging, and uremia. 181 79

Corneal and aqueous levels of topically applied trifluorothymidine (F3T) were compared with and without the collagen shield in normal and damaged rabbit eyes. Shields were presoaked in 1% F3T for 15 minutes prior to application. Rabbits received either a presoaked shield, 1% F3T drops every two hours, or both. Corneal and aqueous levels of F3T were measured at 30 minutes, two, four, and eight hours. If 5 mm epithelial defects were created, the collagen shield and topical F3T drops produced significantly higher levels of F3T than drops alone at all periods tested (P less than .05). A presoaked shield alone produced greater levels of F3T than drops alone at 30 minutes and two hours (P less than .05). Collagen shields did not enhance F3T levels in eyes with intact epithelium. Implications for treatment of herpetic keratouveitis are discussed.
J Cataract Refract Surg 1990 Nov
PMID:Collagen shield delivery of trifluorothymidine. 212 62

Collagen shields immersed in tobramycin solution for one minute were applied to one eye each of 60 patients who had had cataract extraction, penetrating keratoplasty, or epikeratophakia or who had nonsurgical epithelial healing problems. The shields were well tolerated; one patient had the shield removed and one patient lost the shield in the early postoperative period. The surgical patients showed more rapid healing of epithelial defects after surgery with the use of the collagen shield. Patients with acute nonsurgical epithelial problems, such as contact lens abrasions and recurrent erosion, responded to the use of the collagen shield with improved healing. Patients with chronic epithelial defects responded poorly, presumably because underlying abnormalities in Bowman's layer prevented epithelial growth in the area of the defect. No infections were noted in any of the patients. The collagen shields appear to promote enhanced healing in patients with postsurgical and acute epithelial defects and to provide adequate antibiotic prophylaxis against infection in these vulnerable eyes.
J Cataract Refract Surg 1988 Sep
PMID:Clinical uses of collagen shields. 318 29

Collagen shields made of porcine collagen were placed in a solution containing tobramycin sulfate (40 or 200 mg/ml) for five minutes, then applied to rabbit eyes. One, four, or eight hours after application, the corneas, aqueous humor samples, and shields were assayed for antibiotic. At all intervals, the concentration of antibiotic in the corneas and aqueous humor samples exceeded the mean inhibitory concentration for tobramycin, as determined for most strains of Pseudomonas. Shields immersed in 200 mg/ml tobramycin produced significantly higher concentrations of antibiotic in the cornea at one hour than subconjunctival injections of tobramycin (20 mg) (P = .0001). Shields immersed in 40 mg/ml tobramycin produced higher, although not significantly higher, concentrations of antibiotic in the cornea at one hour than subconjunctival injections of tobramycin (20 mg) (P = .318). Shields immersed in commercially available tobramycin drops or injectable tobramycin solution (40 mg/ml) caused no epithelial damage visible by slitlamp examination. Collagen shields containing antibiotics can serve as a vehicle for drug delivery and may prove superior to current methods for preoperative and postoperative antibiotic prophylaxis and the initial treatment of bacterial keratitis.
J Cataract Refract Surg 1988 Sep
PMID:Collagen shield drug delivery: therapeutic concentrations of tobramycin in the rabbit cornea and aqueous humor. 318 30

We compared the corneal penetration in rabbits of topical tobramycin in the presence of collagen corneal shields and bandage soft contact lenses. A collagen corneal shield was placed on six albino rabbit eyes, while therapeutic soft contact lenses (61.4% poly-2-hydroxyethyl-methacrylate/38.6% water) were placed on six eyes. Four control eyes received no shield or contact lens. Topical tobramycin was applied to all 16 eyes every five minutes for six doses. Samples of aqueous humor were removed at 15 and 60 minutes following the last dose. Collagen corneal shields allowed a significant (P less than .05) increase in tobramycin penetration into the anterior chamber at 60 minutes compared with hydrophilic soft contact lenses or controls.
J Cataract Refract Surg 1988 Sep
PMID:Use of collagen corneal shields versus soft contact lenses to enhance penetration of topical tobramycin. 318 31

Posterior capsule opacification following extracapsular cataract extraction is a manifestation of migration of lens epithelial cells onto the posterior capsule. Collagen production by these epithelial cells results in white "fibrotic" opacities. These cells have myoblastic features and their contraction produces wrinkling of the posterior capsule resulting in visual distortion. A high magnification, in vivo specular microscopic study of human posterior capsules following extracapsular cataract extraction is described. In vivo findings correlate with histopathologic observations made on opacified posterior capsules. Lens epithelial cells migrate onto the posterior capsule and produce basement membrane and collagen. Collagen production is associated with a spindle-shaped appearance of the hyperplastic cells. This technique is useful for clinical research on posterior capsule opacification, including the evaluation of interventions designed to treat or prevent this complication.
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PMID:Posterior capsule opacification: a specular microscopic study. 647 22

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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