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)

Serum and aqueous humor lactate dehydrogenase (LDH) levels were assayed in 46 patients with senile cataracts at the time of cataract extraction. The mean aqueous level was 37 IU/liter and the mean serum level 152 IU/liter. In each case, the serum LDH level was higher than the corresponding aqueous LDH. The LDH isoenzyme levels were also determined; LDH 4 and LDH 5 were elevated in cataract aqueous samples, while the serum isoenzymes were normal. The LDH studies of normal and diseased globes must be rigorously standardized to avoid artificially high or low levels.
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PMID:Lactate dehydrogenase levels and isoenzyme patterns in the serum and aqueous humor of adult cataract patients. 92 85

The aim of the present study was to investigate biochemical and morphological changes in rat lenses following long-term UV B irradiation. After an irradiation period of 156 days with follow-up documentation by means of Scheimpflug photography, section-related biochemical analyses of the lenses as well as histological investigations were performed. The video-based Scheimpflug photography (Zeiss SLC) again proved to be an excellent method for the documentation of the UV cataract induced in rats. The biochemical analyses provided indications to potential damaging mechanisms; the section-related technique used allows more precise analyses than the processing of whole lenses in a cataract type restricted to a certain layer, as is the case with UV B damage. The most prominent biochemical findings were a significant decrease in glyceraldehyde-3-phosphate dehydrogenase in the equatorial region in the group with the highest irradiation dosage and a decrease in lactate dehydrogenase in the nuclear region. The histological results reflect the local extent of the UV damage as well as its progression after a prolonged irradiation period.
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PMID:Biochemical and morphological changes in rat lenses after long-term UV B irradiation. 128 10

Development of improved hydrogels for soft intraocular lenses, based on 2-hydroxyethyl methacrylate monomer, requires the use of various other monomers and polymerization additives which have potential ocular toxicity. Three monomers, 2-hydroxyethyl methacrylate, methyl methacrylate, and 2-ethoxyethyl methacrylate, as well as two common inhibitors, hydroquinone and 4-methoxyphenol, were subjected to in vitro cytotoxicity assays as aqueous solutions at different concentrations. A new polymerization initiator, 2,2'-azo-bis-(2,4-dimethyl valeronitrile), was thermally decomposed in water at different concentrations and the products were also assayed for cytotoxicity. Assays were based on incubation with human choroidal fibroblasts. Cell death was evaluated by trypan blue dye exclusion, DNA synthesis inhibition, and lactate dehydrogenase tests. While methyl methacrylate and 2-ethoxyethyl methacrylate were found nontoxic, the other chemicals displayed high cytotoxicity. However, when extracts of synthesized poly(2-hydroxyethyl methacrylate) specimens, differentially treated after polymerization, were subjected to the same assays it was found that toxicity from residual 2-hydroxyethyl methacrylate monomer was lost during steam sterilization and storage in water because of the removal of the monomer through aqueous washing. The lack of toxicity in these specimens suggests that residual contents of inhibitor and initiator are too low to cause toxic effects on choroidal fibroblasts. It is concluded that hydrogels have low cytotoxic effects in vitro.
J Cataract Refract Surg 1991 Mar
PMID:Cytotoxic effects of residual chemicals from polymeric biomaterials for artificial soft intraocular lenses. 204 Sep 72

The activities of lactate dehydrogenase (LDH), glucose 6-phosphate dehydrogenase (G6PD) and glyceraldehyde 3-phosphate dehydrogenase (GAPD) in two zones of the epithelium of the lens of 6- and 27-month-old rats were measured using quantitative cytochemical methods. In both age groups, the epithelium in the equatorial zone showed the highest enzymatic activity. LDH activity was similar in young and old rats in both areas. G6PD and GAPD activities in the central area were similar in both age groups, but their activity was markedly lower in the equatorial zone in old rats compared to young ones. This decrease in G6PD and GAPD activities may play a role in cataract formation.
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PMID:Quantitative cytochemistry of enzymes in the epithelium of ageing rat lenses. 323 91

The diagnostic significance of the lactate dehydrogenase (LDH) level and the protein pattern in the aqueous humour was evaluated in patients with retinoblastoma who presented with leukokoria. The mean LDH level for the 14 retinoblastoma patients was significantly greater than the mean for 6 patients with leukokoria but without retinoblastoma (p less than 0.05) and the mean for 10 patients (controls) with senile cataract (p less than 0.01). Cellulose acetate membrane electrophoresis was performed on the aqueous humour of six of the patients with retinoblastoma, four of the patients with other causes of leukokoria and eight of the control patients. It showed that the protein in the aqueous humour was predominantly albumin in the patients with retinoblastoma; the globulin in these cases was usually beta-globulin. The protein was mostly or completely albumin in the three patients with Coats' disease, and the protein pattern simulated that in normal serum (owing to hemorrhage) in the patient with retinal detachment. No protein was detectable in the aqueous humour of the control patients. Thus, determining either the LDH level or the protein pattern in the aqueous humour can serve as a useful adjunct to the clinical diagnosis of retinoblastoma.
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PMID:Lactate dehydrogenase level and protein pattern in the aqueous humour of patients with retinoblastoma. 667 Nov 53

The effect of cytochalasin D (CD), an actin monomer-stabilizer, has been studied on cataract development in rat lenses. Cataractogenesis was induced by incubating the rat lenses in medium 199 (M199) containing 10(-5) M CD; by the end of 24 h, lenses first developed a visible opacity. The increased lactate dehydrogenase (LDH) activity in the culture medium, leakage of lens cytosolic proteins into the culture medium and observable development of opacity through a dissection microscope were correlated with cell damage associated with cataract formation. Non-denaturing polyacrylamide gel electrophoresis was used to separate three lens LDH isoenzymes. The effect of 1 mM vitamin C (VC) in reducing LDH leakage was also examined. The protective effect of VC on CD-initiated cataractous lenses is significant. This suggest that a portion of the opacity and lens damage may involve oxidative damage to the membrane-cytoskeleton complex which is started by CD, but partially prevented by VC
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PMID:Vitamin C reduces cytochalasin D cataractogenesis. 854 60

The effect of R, S, and racemic forms of a-lipoic acid was tested on the formation of opacity in normal rat lenses incubated with 55.6 mM glucose, as a model for in vivo diabetic cataractogenesis. Control lenses, incubated 8 days with 5.56 mM glucose, did not develop opacities. Formation of lens opacities in vitro was correlated with lactate dehydrogenase (LDH) leakage into the incubation medium. Opacity formation and LDH leakage, resulting from incubation in medium containing 55.6 mM glucose to model diabetes, were both suppressed by the addition of 1 mM R-lipoic acid. Addition of 1 mM racemic lipoic acid reduces these damaging effects to the lens by one-half, while S-lipoic acid potentiated LDH leakage, consistent with the hypothesis that R-lipoic acid is the active form. Although HPLC analysis demonstrated that both stereoisomers of lipoic acid were reduced to dihydrolipoate at comparable rates by the intact lens, the mitochondrial lipoamide dehydrogenase system is highly specific for reduction of exogenous R-lipoic to dihydrolipoic acid. Therefore, stereospecific protection against this opacity is consistent with specific reduction of R-lipoic acid in mitochondria of the vulnerable cells at the lens equator where the first globular degeneration is seen in glucose cataract.
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PMID:Modelling cortical cataractogenesis 17: in vitro effect of a-lipoic acid on glucose-induced lens membrane damage, a model of diabetic cataractogenesis. 867 20

The effect of a novel flavonoid, venoruton (a mixture of mono-, di-, tri- and tetrahydroxyethylrutosides) has been investigated in healthy rat lenses and compared with diabetic cataract modelled in vitro. One mM venoruton was added to medium simulating healthy and diabetic conditions for the incubated lenses; damage was followed by either stereoscopic photography of the lenses under a Cooperative Cataract Research Group operating microscope or with our recently developed method: the leakage of lactate dehydrogenase (LDH) into the lens culture media. The increased LDH activity in the medium and observable development of the opacity were correlated with cell damage, which has been found to be associated with globular degeneration and cataract formation. The extent of opacification and LDH release is reduced if 1 mM venoruton is included in the medium. The protective effect may be related to antioxidant activity against reactive oxygen species: decreased luminol luminescence was shown after venoruton addition to either superoxide-generating hypoxanthine plus xanthine oxidase, or hydrogen peroxide.
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PMID:Modelling cortical cataractogenesis. XVIII. In vitro diabetic cataract reduction by venoruton. A flavonoid which prevents lens opacification. 888 54

Cataract is generally associated with the breakdown of the lens microarchitecture. Age-dependent chemical modifications and cross-linking of proteins are the major pathways for development of lens opacity. The specific alterations in lens proteins caused by glycation with four carbonyl metabolites, fructose, methylglyoxal, glyoxal, and ascorbic acid, were investigated. Decrease in intensity of tryptophan related fluorescence and level of reduced protein sulfhydryl groups, parameters that are indicative for changes in protein conformation, were observed after reaction with all studied carbonyl compounds. Protein carbonyl content, an index for oxidative damage to proteins, was strongly enhanced in methylglyoxal-treated proteins. Cross-linking of glycated proteins was confirmed by polyacrylamide electrophoresis. alpha-Oxoaldehydes were the most reactive in protein aggregation. They also formed specific chromophores absorbing UV light above 300 nm. Significant loss in lactate dehydrogenase activity resulted from incubation with methylglyoxal, followed by glyoxal and ascorbic acid. The results obtained showed that alterations in lens proteins do not follow the specific reactivity of studied carbonyl compounds. Despite the similarity in chemical structures of alpha-oxoaldehydes and ascorbic acid degradation products, they cause specific alterations in lens protein structure with different biological consequences.
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PMID:Comparison between modifications of lens proteins resulted from glycation with methylglyoxal, glyoxal, ascorbic acid, and fructose. 1211 14

Exposure to ultraviolet radiation (UVR) and reactive oxygen species (ROS) can damage the human lens and contribute to cataract formation. Recent evidence suggests that apoptosis in lens epithelial cells (LEC) is an initiating event in noncongenital cataract formation in humans and animals. The present study examines the cellular and molecular mechanisms by which environmental (ultraviolet B [UVB]) and chemical (hydrogen peroxide [H(2)O(2)], t-butyl hydroperoxide [TBHP]) stress induces cell death in an SV-40 immortalized human lens epithelial (HLE) cell line. Treatment of HLE cells with UVB, H(2)O(2), and TBHP significantly decreased cell density with LD50 values of 350 J/m(2), 500 muM, and 200 muM, respectively. Cellular morphology, DNA fragmentation, and annexin/propidium iodide staining consistent with apoptosis was observed only in UVB-treated cells, whereas lactate dehydrogenase (LDH) release was significantly higher in H(2)0(2)- and TBHP-treated cells. In addition, activation of apoptotic stress-signaling proteins, including c-Jun NH2-terminal kinase (JNK), caspase-3, and DNA fragmentation factor 45 (DFF45) was observed only in UVB-treated cells. Inhibition of JNK activity increased UVB-induced cell death, suggesting that this pathway may serve a prosurvival role in HLE cells. These findings suggest UVB predominantly induces apoptosis in HLE cells, whereas H(2)O(2) and TBHP induce necrosis.
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PMID:Apoptotic and necrotic mechanisms of stress-induced human lens epithelial cell death. 1552 44


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