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)

1. Proteins from the cortex and nucleus of the human lens were studied to determine if any changes could be detected in their amino acids during senile cataract formation. 2. Senile nuclear cataract formation was found to be accompanied by a progressive oxidation of cysteine and methionine. The oxidation of methionine and changes in the distribution of the nuclear proteins did not appear to start until about 60% of the cysteine had been oxidized. 3. In the advanced nuclear cataractous lens, about 90% of the cysteine has been oxidized and 45% of the methionine is present as the sulphoxide in the nuclear proteins. The levels of other amino acids appeared to remain constant. 4. Similar, but smaller, changes were found in the cortical proteins in advanced nuclear cataractous lenses, suggesting that the oxidation spreads from the nucleus to the cortex. 5. These changes were discussed with regard to current views on cataract formation and it was concluded that they are probably the result of simple oxidation of the proteins with O2 or H2O2.
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PMID:Oxidative changes in human lens proteins during senile nuclear cataract formation. 86 Dec 52

Exposure of cultured rabbit lens epithelial cells to repetitive doses of UV-B radiation delays their growth and alters the synthesis of specific proteins. Irradiated cells on the shoulder of the survival curve exhibited a dose-dependent decrease in growth when subcultured in serum-supplemented medium. UV-B irradiation did not affect the subsequent attachment efficiency of the cells. Control and UV-B irradiated cells were incubated with [35S]methionine and the pattern of protein synthesis in the cells was analyzed by SDS-PAGE and autoradiography. Analysis of the labeled proteins from cells exposed to UV-B radiation showed the induction of a 32 kD polypeptide and the loss of a 26 kD polypeptide compared with controls. Analysis of the proteins released by the UV-B irradiated cells into the culture medium revealed the 50% loss of a 37 kD radiolabeled protein compared with controls. The alteration of protein synthesis in lens epithelial cells by UV-B radiation may contribute to cataract formation.
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PMID:Effect of ultraviolet-B radiation on protein synthesis in cultured lens epithelial cells. 209 21

Proteins, including lens proteins, were incubated in the presence of 3-hydroxyanthranilic acid (30 HA) under oxidizing conditions. Samples were monitored for alterations in color, fluorescence, sulfhydryl content, lysine availability, methionine content, tryptophan content and protein size. Incubation of proteins with 30 HA produced rapid brown coloration and a correspondingly rapid decrease in sulfhydryl content. Alpha-, beta- and gamma-crystallins were all found to react with 30 HA. An increase in protein fluorescence (excitation 340/emission 425 nm) accompanied the color development. No significant decrease in the content of tryptophan or any other amino acid was detected by amino acid analysis. The levels of available lysine were not affected significantly by treatment with 30 HA. Oxidation of methionine to methionine sulfoxide and the covalent cross-linking of polypeptides was obtained by subsequent treatment of the tanned proteins with H2O2. The modifications observed are very similar to those found in the senile nuclear cataract lens.
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PMID:The reaction of proteins with 3-hydroxyanthranilic acid as a possible model for senile nuclear cataract in man. 251 71

With an amino acid analyzer, we measured amino acids and related compounds in serum and aqueous humor from normal Chinese and some patients with extreme myopia or senile cataracts. Forty peaks were well resolved, and their areas were used to quantify each compound. In the myopic patients, glutamate, alpha-aminoadipate, and methionine concentrations in serum were 10-fold those in the normal subjects. Values for most of the other amino acids and related compounds were also higher in myopic patients' sera. In the cataract patients, concentrations of most of these compounds were lower in serum but higher in aqueous humor than for the normal subjects. Tryptophan was present in significant amounts in sera from the normal subjects, but was not detectable in the senile-cataract patients. The ratio of amino acid concentration in aqueous humor to that in the serum (Ch/Cs) was higher in the cataract patients than in normal subjects for almost all of the compounds we measured.
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PMID:Amino acid concentrations in serum and aqueous humor from subjects with extreme myopia or senile cataract. 340 67

21 amino acids have been determined in aqueous humor obtained during microsurgical intraocular procedures in 30 patients with senile cataract and 27 patients with primary open-angle glaucoma. All individual amino acids showed higher levels in the glaucomas than in the cataracts: this is valid at 2p less than 0.05 for threonine, serine, asparagine, glutamine, methionine, tyrosine, phenylalanine, histidine, tryptophan, and arginine.
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PMID:Amino acid pattern in human aqueous humor of patients with senile cataract and primary open-angle glaucoma. 406 71

Female rats were fed defined diets limiting in one or more of certain amino acids and with or without vitamin E throughout gestation and lactation. Deficits of tryptophan, phenylalanine/tyrosine, or methionine/cystine reduced the body weight of progeny to about 50% or less of normal but only low tryptophan was cataractogenic. When total dietary amino acids were 12.4%, a low (65 mg%) level of tryptophan resulted in 34% incidence of cataract if vitamin E was simultaneously withheld. Elevation of total amino acids to 24.8% while maintaining tryptophan at 65 mg% caused 70 or 90% incidence of nuclear lens opacities in the presence or absence, respectively, of vitamin E. Maternal dietary amino acid imbalance was also associated with a 50% decrease in lens insoluble (membrane) proteins in the progeny independent of dietary vitamin E or the occurrence of opacities.
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PMID:Cataract formation following limited amino acid intake during gestation and lactation. 646 60

The oxidation state of methionine and cysteine in normal and cataractous lenses is reported. In young lenses no oxidation was detected in any protein fraction examined. Only the intrinsic membrane fraction and membrane-related components showed evidence of oxidation in old (60-65 years of age) normal lenses. However, in a similar age group, with the development of cataract, progressive, dramatic changes were observed. With severe cataracts, 60% or more of the methionine in membrane-associated components was found in the methionine sulfoxide form, and methionine sulfone was observed in one case. Most of the cysteine was found oxidized to either the disulfide form or putative cysteic acid. Mixed disulfides with glutathione were observed. Oxidative changes in soluble components as illustrated by alpha-crystallin occurred more gradually. The data clearly support the viewpoint that extensive oxidation of lens proteins occurs with cataract and that it begins at the lens fiber membrane.
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PMID:Selective oxidation of cysteine and methionine in normal and senile cataractous lenses. 692 83

Water soluble extracts from cataractous and normal salmonid lenses were subjected to thin-layer isoelectric focusing. The cataracts resulted from deficiencies of specific nutrients in diets fed to three species of salmonids as follows: (1) rainbow trout (Salmo gairdneri) fed a diet deficient in riboflavin; (2) Atlantic salmon (Salmo salar) fed a diet deficient in methionine; and (3) rainbow trout and lake trout (Salvelinus namaycush) fed a diet deficient in zinc. In all tests, the protein pattern of cataractous lenses differed from that of normal lenses. Each cataract caused by the different dietary deficiencies had a specific pattern of soluble lens proteins. Even though the general patterns of the soluble lens proteins for all three salmonids though the general patterns of the soluble lens proteins for all three salmonids studied were similar, a specific pattern was unique for each of the species.
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PMID:Differentiation of soluble proteins in cataracts caused by deficiencies of methionine, riboflavin or zinc in diets fed to Atlantic salmon, Salmo salar, rainbow trout, Salmo gairdneri, and lake trout, Salvelinus namaycush. 714 Mar

The relationship between cataract extraction and diet was considered in a case-control study conducted in northern Italy. A total of 207 patients who had cataract extraction and 706 control subjects in a hospital for acute, nonneoplastic, nonoculistic, nondigestive tract diseases were interviewed during their hospital stay. Odds ratios (ORs) and their 95% confidence intervals (CIs), according to the intake of alcohol, coffee, tea, and cola, and frequency of intake of 34 food items and 8 micronutrients were derived from multiple logistic regression equations, including terms for age, sex, education, smoking status, body mass index, diabetes, and total calorie intake. Alcohol, coffee, decaffeinated coffee, tea, and cola intakes were not associated with cataract extraction. Among food items, reduced ORs for cataract extraction (highest tertile of intake compared to the lowest), with a significant inverse trend in risk, were found for intake of meat (OR 0.6, 95% CI 0.4 to 0.9), cheese (OR 0.7, 95% CI 0.5 to 1.0), cruciferae (OR 0.5, 95% CI 0.3 to 0.8), spinach (OR 0.6, 95% CI 0.4 to 0.9), tomatoes (OR 0.5, 95% CI 0.4 to 0.8), peppers (OR 0.7, 95% CI 0.4 to 1.1), citrus fruit (OR 0.5, 95% CI 0.2 to 1.3), and melon (OR 0.5, 95% CI 0.4 to 0.8). A significant increase in risk was found for the highest intake of butter (OR 2.8, 95% CI 1.2 to 6.4), total fat (OR 1.8, 95% CI 1.2 to 2.8), and salt (OR 2.4, 95% CI 1.4 to 4.0) compared to the lowest, and for consumption of oil other than olive oil (OR 1.6, 95% CI 1.1 to 2.2). Among micronutrients, lower ORs for cataract extraction (highest quintile of intake compared to the lowest) were found for intake of calcium (OR 0.5, 95% CI 0.3 to 0.8), folic acid (OR 0.4, 95% CI 0.2 to 0.7), and vitamin E (OR 0.5, 95% CI 0.3 to 1.0), while estimated intakes of methionine, retinol, beta-carotene, and vitamins A, C, and D were not associated. Thus, this study indicates that diet plays a considerable role in the risk of cataract extraction in this Italian population, with a protective action played by some vegetables, fruit, calcium, folic acid,and vitamin E, and an increased risk associated with elevated salt and fat intake.
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PMID:Food and nutrient intake and risk of cataract. 868 Jun 24

Lenses from Rhesus monkeys were maintained in protein-free medium and both their biochemical and histological changes were examined. Lenses were dissected under a dissecting microscope to ensure minimal contamination by other ocular tissue, which allowed successful observation of whole lens morphology during culture. Lenses in culture showed no acute leakage of protein into medium, indicating that they had not been physically damaged during dissection. Cultured lenses remained transparent for 21 days without any noticeable histological changes. Even at 21 days of culture, 35S-methionine incorporation into lens protein was approximately 60% of the level observed in fresh lenses. The amounts of most protein species were rather constant in the lens capsule/epithelium throughout culture, but the amount of crystallins gradually decreased during the first 14 days, of culture due to selective decrease in crystallin synthesis. After day 14, both the amount of crystallins and their synthesis became stable. When 30 mM fructose, present in the control medium, was replaced with 30 mM xylose, lens opacification with some histological abnormalities such as vacuole formation was observed. In the xylose-induced cataract, the protein synthetic activity decreased dramatically. This system would be a valuable tool in investigating the mechanisms of lens homeostasis as well as mechanisms of cataractogenesis in primate lens.
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PMID:Long-term maintenance of monkey lenses in organ culture: a potential model system for the study of human cataractogenesis. 894 49


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