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)

A specific reagent DACM [N-(7-Dimethylamino-4-methyl-3-coumarinyl)maleimide] is used to study the -SH groups in lens proteins of normal and galactose cataractous rats. DACM when reacts readily with -SH groups form strong fluorescent adducts. The two -dimensional electrophoresis with DACM pre-labeled proteins is a simple and sensitive method for detecting -SH groups of protein subunit. In the present study, based on IEF/SDS-PAGE electrophoretically characterized soluble crystallins, describes specific changes in -SH groups of protein subunit during the development of galactose cataract. The contents of -SH groups of crystallins are progressively decreased in cataractous (5+) lens, the reduction of -SH content in alpha- and beta- crystallin protein subunits of the normal and cataractous lens proteins is also noticeable.
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PMID:Assessment of sulfhydryl group in individual rat lens protein subunits during galactose cataract development. 784 79

The occurrence of age-related cataract associated with a persistent hyaloid vascular system is the most prominent feature in SAMP9, an inbred strain of Senescence-accelerated Mouse. To examine the cataractogenesis, we analysed protein changes in the process of cataract formation in the lens. The cataractous lenses showed a striking decrease in water-soluble protein content, in contrast to increases in the amount of water insoluble protein. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blots of water-soluble protein in the cataractous lenses showed additional high molecular weight beta-crystallin proteins of about 43 kDa, concomitant with decreased amounts of 29-kDa and 31-kDa beta-crystallins and 21-kDa gamma-crystallin, as compared with findings in normal lenses. Although there was no apparent difference between the patterns of SDS-PAGE of urea-soluble and urea-insoluble proteins isolated from cataractous and normal lenses, slightly increased reactivity of bands around 43 kDa against anti-beta-crystallin antibody was observed in cataractous lenses. The calcium content was elevated and activity of transglutaminase was increased in the cataractous lenses. While the molecular weight of beta-crystallin polymers cross-linked in vitro by exogenous transglutaminase was not completely compatible with those of high molecular weight beta-crystallins observed in the cataractous lenses, these findings do suggest the contribution of this enzyme to production of high molecular weight beta-crystallins and to insolubilization of these proteins in the cataractous lenses in SAMP9.
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PMID:Protein alterations in age-related cataract associated with a persistent hyaloid vascular system in senescence-accelerated mouse (SAM). 785 22

The total proteins, water--soluble proteins and the urea--soluble proteins of the lens from fetal, adult and senile cataract were determined by SDS--PAGE. It was found that there was a 43KD polypeptide in the capsular--epithelium of all lens stated above. The band on SDS-PAGE corresponding to 43KD polypeptide was wide in the water--soluble proteins of the cortex and nucleus of the lenses obtained from over 14-year-old individuals. It became blurred in the urea--soluble proteins of cortex and nucleus of lens with aging, whereas it became almost disappeared in the senile cataract lens.
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PMID:[The 43KD polypeptide in the proteins of human lens]. 795 52

Restriction of dietary calorie intake is associated with life extension and with the delay of age-related disorders. Preliminary studies demonstrated that by feeding the Emory mouse a diet restricted by 21% in calories cataract and insolubilization of protein could also be delayed. To observe the effects of calorie restriction over prolonged portions of adulthood, Emory mice were fed the control diet (C) or a diet restricted by 40% in calories (R). Feeding the R diet was associated with delayed formation or progress of cataract over virtually the entire second half of life. At 11 months of age, bilateral grade 5 cataracts were present in 17% and 2% of C and R lenses, respectively. At 22 months of age, bilateral grade 5 cataracts were present in 90% and 18% of C and R lenses, respectively. The distribution of alpha-, beta-, and gamma- crystallins in the water-soluble, urea-soluble, and SDS-soluble fractions indicates more similarities than differences between C and R lenses with a specific grade of cataract or of a given age. However, there were significant and abrupt (after grade 4 cataract) losses of particular gamma-crystallins; gamma-crystallins which were not prominent at earlier stages became the major gamma-crystallin moieties. Losses of alpha-crystallins were also noted upon cataract formation or aging in most of the fractions. Aggregates including gamma- and alpha-crystallins also accumulate faster in the C group.
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PMID:Cataract incidence and analysis of lens crystallins in the water-, urea- and SDS-soluble fractions of Emory mice fed a diet restricted by 40% in calories. 813 32

Cigarette smoking is a main source of cyanide in human body, which can be taken as a risk factor of cataract formation. In this study, combined gas chromatography and mass spectrum (GC/MS) was used to determine the amino acid hydantoin after the incubation of soluble human lens gamma-crystallins with cyanate. The carbamylated amino acids obtained by this procedure are alanine and glycine, which are N-terminal amino acids of gamma-crystallin, and leucine. The aggregate, which can be observed in carbamylated gamma 1-crystallin on SDS-PAGE, may be related to the formation of disulfide and non-disulfide covalent bonds, and it seems that gamma 2 and gamma 3-crystallins can not be aggregated to any great extend. The results in this study indicate that the GC/MS is an effective method for analyzing the carbamylation of lens proteins; gamma-crystallin may play a very important role in the formation of cataract associated with accumulation of cyanate in human body, such as heavy smoking.
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PMID:Carbamylation of human lens gamma-crystallins: relevance to cataract formation. 816 8

The interaction of human and bovine alpha-crystallins with bovine lens membranes was evaluated using binding curves and Scatchard plots constructed from scans of SDS-PAGE gels and/or from the association of [14C]-leu alpha-crystallin with the membranes. No differences were observed for total bovine, normal human 19 and 88 year old and cataractous alpha-crystallins. In each case, interaction takes place through two distinct processes, a) a high affinity (Kd = 1 x 10(-8) M) binding with low capacity (25 mg alpha-crystallin/g membrane protein) and b) partitioning (Kp = 0.25 l/g membrane protein). Loss of the high-affinity binding component was observed for bovine nuclear alpha-crystallin. Contrary to previous reports, it is concluded that cataract formation does not affect the ability of human alpha-crystallins to interact with bovine lens membranes. Reanalysis of previously published data supports this conclusion.
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PMID:On the interaction of alpha-crystallin with membranes. 819 71

Light scattering intensities of rat lenses obtained in the I,, and I+ modes were analysed using the random density and orientation fluctuation theory. Rat lenses incubated in calcium rich media had the same density fluctuation parameters as rat lenses incubated in control (low-calcium) media. However, the correlation length of the orientation fluctuations decreased during cataract formation by 100 to 200 nm while the amplitude of the fluctuations increased. The correlation length, or the size of the optically anisotropic domains, is related to the size of the cytoskeleton, especially vimentin. Vimentin has been shown to degrade when calcium activates calpain. This has been observed in SDS-gel electrophoretic experiments in rat lenses in calcium rich media. The amplitude factor of orientation fluctuations, that is, the mean squared deviation from the average refractive index, increased between two- and seven-fold during cataractogenesis. These results indicate that calcium cataract formation at the beginning (first 72 hr incubation) has little to do with aggregation or syneresis but it is largely the result of changes in the intrinsic birefringence of the lens due to vimentin degradation.
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PMID:Light scattering parameters of rat lenses with calcium-induced cataracts. 869 36

This study of lens protein composition found that some cytoskeletal proteins were degraded during the earliest stages of cataract formation. Cataract was induced in 13-14 day old rats by a single subcutaneous injection of sodium selenite (19 mumol kg-1). By 24 hr after the injection of selenite, the ratio of insoluble to soluble protein increased as lens opacification began. The increase in insoluble protein aggregates was correlated with an accelerated loss of proteins having molecular weights of 42, 55/57 and 235 kDa which reacted with antibodies to the cytoskeletal proteins actin, tubulin/vimentin and spectrin, respectively. We observed the loss of 49, 60 and 90 kDa proteins which were not identified. In the lenses of animals protected from protein aggregation and opacification by administration of 1.5 mmol kg-1 pantethine, the pattern of proteins in SDS-PAGE gels resembled the pattern for proteins from transparent lenses of normal untreated animals and loss of cytoskeletal proteins was prevented.
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PMID:Loss of cytoskeletal proteins and lens cell opacification in the selenite cataract model. 919 90

Macaca nemestrina pig-tail macaques were administered daily oral doses of 3.85 or 5.78 mg/kg of cortisol for 1 year. The ages of the macaques were from 19 to 29 years. After 1 year, lenses were observed using a slitlamp ophthalmoscope and the stage of cataract was classified in each eye. Enucleated lenses were analyzed for content of soluble and insoluble proteins. Lens proteins were analyzed using SDS polyacrylamide gel electrophoresis (SDS-PAGE) and the changes in lens proteins were quantified using densitometry of the individual gels. Untreated control lenses were obtained over the range of 4 to 29 years of age and the proteins were analyzed. A slow progressive increase in the cataract stage and in the proportion of insoluble protein aggregates corresponded with the animal age, not the cortisol treatment. The observed changes in the protein components may suggest an important role for cytoskeletal proteins in lens transparency during aging. Exposure to high doses of oral steroids over a period of 1 year did not result in detectable modification of crystallin or cytoskeletal proteins. Even at high doses, longer exposure may be necessary to produce the cataract associated with steroid administration.
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PMID:Protein changes during aging and the effects of long-term cortisol treatment in macaque monkey lens. 920 Jan 62

microPx-11, a ferriheme undecapeptide proteolytic degradation product of cytochrome C is shown to be a peroxidase with broad specificity degrading H2O2 and tertiary butyl hydroperoxide. It is also capable of effectively eliminating superoxide and hydroxyl radical. The peroxidase loses activity in the presence of peroxide unless it is stabilized by ascorbate (Asc) or solutions such as aqueous humor or medium 199. While thiol but not disulfides inactivates the microPx-11, it is not inhibited in the presence of the rat lens which has a high GSH content. microPx-11 at concentrations 10 to 50 fold greater than are required to achieve good protective activity exhibits no toxicity based on cell viability, ATP levels and lens transparency after long-term incubations of alpha TN4-1 cells or cultured rat lens. The peroxidase is capable of protecting cultured rat lenses from photochemical stress where H2O2, O2.- and OH. are generated based on transparency, choline transport, epithelial cell viability and protein integrity as indicated by SDS-PAGE of the rat lens protein. In the absence of the peroxidase, extensive epithelial cell death and other degradative changes are observed. The DNA of alpha TN4-1 cells can also be protected from H2O2 induced single strand breaks by the microPx-11. The overall results suggest that a number of cytochrome C proteolytic degradation products are peroxidases which may be effective anti-cataract agents protecting the lens from oxidative stress.
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PMID:Microperoxidases catalytically degrade reactive oxygen species and may be anti-cataract agents. 946 80


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