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)

Bendazac is an oxyacetic acid with anti-inflammatory, antinecrotic, choleretic and antilipidaemic properties, but its principal effect is to inhibit the denaturation of proteins. The lysine salt, which is better absorbed than the parent compound after oral administration, has been evaluated as a treatment for cataract, a condition which appears to result mainly from the denaturation, aggregation and precipitation of proteins within the lens. Results from a very small number of preliminary studies using objective photographic and densitometric methods have suggested that oral bendazac lysine, usually at a dosage of 500 mg 3 times daily, can stabilise the progression of lens opacification in patients with cataract. Significant improvements in individual and mean visual acuities in treated patients have been reported by several studies, but this parameter is not universally accepted as a reliable index of lens status. Preliminary studies evaluating bendazac lysine 0.5% eyedrops have reported comparable results to those obtained with oral treatment. Overall, tolerability of the drug has been good in studies to date. A dose-related laxative effect and other gastrointestinal disturbances are the most common adverse effects associated with oral therapy, and a transient burning sensation is the most commonly reported symptom occurring with eyedrop application. Bendazac lysine is one of a number of agents which have been introduced for the management of cataract. Although the results of preliminary studies have suggested that the drug may be useful for delaying the progression of cataract, further clinical studies using proven objective methods are required to fully establish its value in the management of this condition and its long term tolerability.
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PMID:Bendazac lysine. A review of its pharmacological properties and therapeutic potential in the management of cataracts. 219 Jul 95

A modified Zeiss slit lamp coupled with a digital image-processing system was used to evaluate objectively changes in lens transparency over 1 year at 4-month intervals in 150 eyes of 92 patients affected by early senile cataract. A total of 59 patients were treated daily with 1.5 g bendazac-lysine, and 33 patients constituted the control group. At follow-up, visual acuity was also tested using Snellen letter charts at variable contrast to provide an additional parameter closer to traditional methods. Results indicate that the minimal angle of resolution at 10% contrast (MAR10) and the mean gray-level value of the lens image obtained by retroillumination (MLR) are sensitive to early changes in lens transparency. Using MAR10 as a parameter, the control group showed a significant, progressive worsening of the lens status over 12 months, whereas the treated group exhibited no significant changes. MRL indicated the same behaviour as MAR10, although lens damage was detected later in the control group. The results show that bendazac-lysine may delay the formation of lens opacities.
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PMID:Medical treatment of senile cataract: clinical investigation of bendazac-lysine using objective and subjective methods. 233 48

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

A double-masked placebo-controlled clinical trial with hard data evaluation by image analysis of Scheimpflug photographs taken at baseline and 6, 12 and 18 months after starting treatment was performed to assess the efficacy of bendazac lysine in four different types of senile cataract. The study had a classical split-plot design. For statistical evaluation, the analysis of variance and covariance for repeated measures were used for three different lens sections: anterior capsule and superficial layer, anterior cortex and nucleus. In the entire group of 53 evaluable patients (without separation into cataract-type subgroups), there was a significantly less increase over time in light scattering (i.e. film blackening) of the anterior cortex and nucleus with bendazac lysine than with placebo. There was also a strong trend in favour of the active drug at the anterior capsular level. Patients with water clefts and spokes showed a significantly less light scattering of the anterior capsule and cortex when treated with bendazac lysine. Those with nuclear changes also showed significantly less light scattering of the anterior cortex and nuclear region with the active drug than with placebo. The number of patients with subcapsular and wedge-shaped (cuneiform) cataracts was too small to be adequately assessed by statistical procedures. Nevertheless, there were indications of a beneficial effect of bendazac lysine on all the lens sections in patients with subcapsular cataracts and on the anterior cortical region in those with wedge-shaped cataracts. In conclusion, this study showed that the increase in light scattering over time, i.e. the progression of cataract, is less in bendazac lysine-treated patients than in those treated with placebo.
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PMID:Bendazac lysine in selected types of human senile cataract. A long-term double-masked placebo-controlled clinical trial with multilinear densitometric image analysis of Scheimpflug photographs. 267 21

We measured how much glycated protein there was in rat eye lenses with different degrees of cataract, using an antibody against glucitol-lysine. Streptozotocin-diabetic (STZ) rats were in some cases treated with insulin (STZ + INS); control rats were normal. We graded the cataracts from 0 (transparent) to 3 (entirely opaque). STZ rats had significantly more grade 3 cataracts, and STZ + INS rats more grade 1 cataracts, than other groups. Grade 3 lenses had significantly more glycated protein than those of grade 0 (10.8 +/- 2.7 vs. 1.0 +/- 0.4 nmol/mg protein), grades 1 and 2 being intermediate. Glycosylated hemoglobin levels correlated similarly with severity of cataract. These data are consistent with the greater incidence of cataract among diabetics than among non-diabetics, and suggest that lens protein glycation contributes to the development of cataract.
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PMID:Lens protein glycation and the subsequent degree of opacity in streptozotocin-diabetic rats. 269 28

The effect of (1-benzoyl-1H-indazol-3-yl)oxylacetate L-Lysine (bendazac-lysine) on some enzymatic activities involved in the metabolism of reduced glutathione (GSH) was studied in the rabbit lens during developing cataract induced by a single dose of X-rays (2000 rads). The specific activities of glutathione reductase (G.R.), glutathione peroxidase (GSH.Px) and glutathione S-transferase (GSHS-tr.) do not change following irradiation and treatment with bendazac-lysine. The activity of the same enzymes expressed as a function of water soluble proteins (WSP) per lens significantly decreases (P less than 0.01) as compared to controls in the irradiated lens not treated with bendazac-lysine (ILNTB) at the 8th week, whereas no significant decrease as compared to controls is observed in the irradiated lens treated with bendazac-lysine (ILTB). In the ILNTB the specific activity of glucose-6-phosphate dehydrogenase (G6PDH) is reduced by 10% after 0.3 weeks and by 29% after 12 weeks. In the ILTB the specific activity of G6PDH is reduced by 8% after 0.3 weeks and by 14.5% after 12 weeks. The specific activity of superoxide dismutase (SOD) in the ILNTB is reduced by 19% after 0.3 weeks and reached 31% after 12 weeks. In the ILTB the specific activity of SOD is reduced by 11% after 0.3 weeks and 19.8% after 12 weeks. The mechanism of protective effect of bendazac-lysine on cataract is discussed.
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PMID:Effects of bendazac L-lysine salt on some metabolic enzymes of glutathione in the rabbit lens after X-irradiation. 361 May 98

The effects of bendazac-L-lysine salt (bendazac-lysine) on some biochemical parameters (soluble and insoluble proteins, reduced glutathione, sulphydryl and disulphide groups, water content) in rabbit lens at different times after X-rays (2000 rads) were studied. The mature cataract (swelling and total lens opacity) developed 11-12 weeks after irradiation. In the mature cataract, the irradiated lenses not treated with bendazac-lysine (ILNTB) show a 32% increase in water content compared with controls; this increase is 12% in irradiated lens treated with bendazac-lysine (ILTB). Twelve weeks after irradiation the concentration of insoluble proteins in the controls, ILNTB and ILTB is 7.6%, 52.3% and 18.3% respectively. After 6, 8 and 12 weeks the concentration of reduced glutathione in ILNTB decreases by 23%, 81% and 92% as compared with the controls. In the ILTB the decrease is present only 8 and 12 weeks after X-irradiation and is of 55% and 69%, respectively. The sulphydryl-group content in the soluble proteins in ILNTB compared with the controls decreases by 26%, 38% and 47% after 6, 8 and 12 weeks, while in the ILTB a decrease is observed only after 8 and 12 weeks and is 6% and 12%, respectively. The decrease of the sulphydryl groups parallels the increase of the disulphide groups. This increase is already significant (P less than 0.01) after 6 weeks in the ILNTB, whereas it becomes significant in the ILTB only after 8 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of bendazac L-lysine salt on X-ray-induced cataract in the rabbit lens. 369 6

Incubation of lens in Ca2+-containing media, considered by several investigators to be a useful model of cataract formation, gave rise to significant alterations in the covalent structures of various proteins. In rabbit lens, when sodium dodecyl sulfate-polyacrylamide gel electrophoresis was used after reduction of disulfides in urea, the most readily observable changes were (i) disappearance of 210K, 95K, and 60K proteins, (ii) modifications of alpha crystallin subunits, (iii) alterations of beta H crystallins, and (iv) de novo production of 55K and higher molecular weight polymers. The addition of leupeptin inhibited the disappearances of 210K, 95K, and 60K proteins and the alteration of alpha crystallins, suggesting that all these were caused by a Ca2+-activated protease. The proteolytically sensitive 60K species was identified as vimentin, a component of intermediate filaments. Formation of the 55K material and of higher molecular weight polymers during Ca2+ treatment of the lens could be prevented by histamine, a compound known to inhibit the transglutaminase-mediated cross-linking of proteins by epsilon-(gamma-glutamyl)lysine peptide bonds in other biological systems. It could also be shown by immunoblotting that an antibody raised against the 55K material reacted selectively with beta crystallins of normal lens. This indicates that the 55K product is in all likelihood an essential intermediate toward higher polymers and that the 55K product is a cross-linked dimer of certain polypeptides of beta crystallin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Formation of a 55 000-weight cross-linked beta crystallin dimer in the Ca2+-treated lens. A model for cataract. 398 92

Steroid-induced cataracts occur as a consequence of prolonged, therapeutic levels of glucocorticoids. Previous studies have shown that these lens opacities are associated with the occurrence of covalent glucocorticoid-lens protein adducts. In vitro, the glucocorticoid prednisolone nonenzymatically modifies the lysine residues of lens crystallins. This modification increases the reactivity of protein thiols and leads to the formation of high-molecular-weight, disulfide-linked aggregates. Prednisolone-induced aggregates result in an opalescence in the crystallins solution which is reversed by the addition of dithiothreitol. The acetylation of lens proteins prior to incubation inhibits both the incorporation of prednisolone and the development of opalescence. Gel filtration chromatography of the prednisolone lens protein incubations shows that the majority of the protein-incorporated prednisolone is associated with the disulfide-linked complexes. Similar analysis of proteins obtained from a human steroid-induced cataract demonstrates that prednisolone adducts which form in vivo are also present in reducible, high-molecular-weight complexes. These results implicate the nonenzymatic modification of lens crystallins in the cataractogenic effect of glucocorticoids and suggest possible pharmacological strategies in preventing this toxic manifestation of steroid therapy.
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PMID:Nonenzymatic modification of lens crystallins by prednisolone induces sulfhydryl oxidation and aggregate formation: in vitro and in vivo studies. 406 53

A protein polymer characteristically present in human cataract was shown to contain significant amounts of gamma-glutamyl-epsilon-lysine isopeptides. It is proposed that these crosslinks are produced by the action of transglutaminase (R-glutaminyl-peptide:amine-gamma-glutamyl-yltransferase, EC 2.3.2.13), which is all the more plausible because lens contains the enzyme and endogenous protein substrates for it. The enzyme is similar to that obtained from liver and is Ca2+ dependent. Highest apparent activity is found in lens cortex. When cortex homogenate from the rabbit was incubated in the presence of Ca2+ with either [14C]putrescine or with dansylcadaverine, a a selective incorporation of the radioactive or fluorescent amine into the heavier subunits (Mr approximately 26,000 and 30,000) of beta-crystallins could be demonstrated. Possible modes of regulating the crosslinking activity of this enzyme in lens are discussed.
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PMID:Lens transglutaminase and cataract formation. 611 45


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