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)

Normal and streptozotocin diabetic female Wistar rats were given vitamin E in the diet as the tocopherol, acetate, or succinate form (2,850 IU/kg food). At the end of 6 weeks, the rats were examined for weight gain or loss, general body condition, and cataracts. At sacrifice, blood was collected for measurement of serum glucose, and gamma-crystallin levels were measured in aqueous and vitreous humors using a radioimmunoassay. One lens was homogenized in 8 M guanidinium chloride for ATP analysis. In normal rats, gamma-crystallin was detected in both aqueous and vitreous humors, with the higher concentration in the vitreous humor. Diabetes caused a sixfold increase in gamma-crystallin in both the aqueous and vitreous humors. Diabetes also led to a significant worsening in general body condition, loss of body weight, formation of cataracts, and decrease in lens ATP levels. Addition of vitamin E and vitamin E succinate, but not vitamin E acetate, to the diet resulted in reduction of gamma-crystallin leakage into the vitreous humors and an increase in body weight. There was no improvement noted for the lens ATP levels, the general body condition, or visual cataract score. Neither streptozotocin-induced diabetes nor vitamin E in the diet appeared to affect the weight of the lenses.
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PMID:Modeling cortical cataractogenesis: IX. Activity of vitamin E and esters in preventing cataracts and gamma-crystallin leakage from lenses in diabetic rats. 262 5

A Norwegian family showed 20 cases of verified or suspected diabetes in 5 generations, 13 being females and 7 males. In 12 patients the diagnosis was established at 26 years of age or earlier. Fourteen patients were definitely non-insulin-dependent. A high frequency of severe diabetic ophthalmopathy was noted, five patients were blind, two had proliferative retinopathy, and one simplex retinopathy and cataract. Five patients from the last 3 generations were islet cell antibody negative and C-peptide positive. In selected patients the serum insulin response to oral glucose was markedly reduced. HLA determinations in these patients showed absence of DR3 and DR4, and presence of DR2. The inheritance of diabetes in this family is compatible with an autosomal, dominant trait, and the majority of cases fulfilled the criteria of maturity-onset diabetes of the young. The high frequency of severe ophthalmopathy underscores that this disease may have an unfavourable evolution.
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PMID:Maturity-onset diabetes of the young. Studies in a Norwegian family. 264 41

Intracapsular cataracts obtained within 3 h after surgical extraction were photographed with the CCRG technique and immediately subjected to fluorescence spectroscopy followed by 31P- and 13C-nuclear magnetic resonance (NMR) spectroscopy. Fluorescence spectroscopy demonstrates an excellent correlation between nontryptophan fluorescence intensities and lens color. An interesting correlation was also observed between the degree of light scatter as determined by the 290-nm excitation peak for intrinsic lens tryptophan fluorescence and the CCRG (photographic) appearance of these cataractous lenses. Based on 100 cataracts analyzed, there is a strong correlation between this kind of light scattering measurement and the type and degree of lens opacification. A similar correlation is evident with the 31P-NMR organophosphate profiles in the lenses in which the sugar phosphate levels are elevated only in diabetic patients with cataracts ('diabetic cataracts'). Aside from fluorescence and 31P-NMR spectroscopy, selected lenses were also incubated with 5.5 nM 13C-glucose as soon as they were obtained, and the foregoing spectroscopy was performed, followed by 13C-NMR analyses to detect and monitor for sorbitol accumulation in young versus old normal lenses and in diabetic cataracts. These studies clearly demonstrate a direct correlation between nontryptophan-fluorescent chromophore levels, light scattering (determined by tryptophan excitation peaks), lens age and cataract type. In addition, the organophosphate profiles clearly delineate the diabetic cataracts, and the 13C-NMR spectra correlate well with the age-related decrease in aldose reductase activity.
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PMID:Photographic and spectroscopic correlations of human cataracts. 271 Apr 94

The effect of vitamin E-containing liposome on experimental sugar cataract formation in vitro was investigated. The lenses of male Wistar rats aged 6 weeks were prepared by incubating with 55. 6 mM glucose with vitamin E-containing liposome (dipalmitoyl phosphatidylcholine: DPPC). We examined the formation of lens opacity and assayed vitamin E and its related compounds. Incubation with vitamin E-containing liposome prevented sugar cataract formation. In Addition, vitamin E concentration in lens was significantly elevated by incubation with vitamin E-containing liposome. In lenses of the high level glucose group incubated without vitamin E-containing liposome, lipid peroxide (LPO) content was increased, but in lenses of the high-level glucose group incubated with vitamin E-containing liposome the increase was significantly inhibited at each incubation time. Vitamin E had no effect either on the decrease of reduced glutathione (GSH) or the increase of sorbitol content in lens incubated with high level glucose medium. In conclusion vitamin E-containing liposome was transported from medium to lens well and was significantly effective in preventing experimental sugar cataract formation in vitro. The protective effects of vitamin E are probably caused not only by its antioxidative action.
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PMID:[Effect of vitamin E-containing liposome on experimental sugar cataract]. 275 Jun 6

The purpose of the present study was to examine the effects on cataractogenesis of daily sc administration of the Ca2+ antagonist drug verapamil to diabetic rats. Streptozotocin-induced diabetic rats were given verapamil half-way through the 8-week experimental period or during the full 8 weeks of diabetes. Verapamil administration had no effect on the high blood glucose values, low circulating insulin levels, or elevated triglyceride and cholesterol concentrations in the diabetic rats. Untreated diabetic rats had a 90% incidence of cataracts. Four weeks of verapamil administration reduced this incidence to 41%, and a full 8 weeks of drug treatment further lowered the incidence to 20%. Diltiazem, another Ca2+ antagonist, lowered the incidence of cataracts in the diabetic rats to a similar extent. Verapamil administration to the diabetic animals also partially protected against the presence of retinal microangiopathy in the diabetic animals. Lenticular hydration and lipid accumulation were only indirectly related to cataractogenesis in the diabetic rats and its protection by verapamil treatment. Lenticular electrolyte imbalance, particularly Ca2+, in the diabetic animals was closely correlated with cataract formation, and verapamil significantly reduced the alterations in these ion concentrations. The present results demonstrate the efficacy of verapamil as a protective agent against cataractogenesis and some retinal damage in diabetic animals. Most importantly, this occurs in the absence of any change in the glycemic status of the diabetic animals. The findings strongly support a role for lenticular Ca2+ imbalance in cataract development in diabetes and provide initial evidence to suggest its clinical use in the diabetic population at risk for blindness.
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PMID:Cataract formation is prevented by administration of verapamil to diabetic rats. 275 74

We report the results of a series of nuclear magnetic resonance (NMR) experiments designed to investigate the relationship between particular aspects of glucose metabolism and cataract formation in the rabbit lens. The glucose metabolism of the rabbit lens incubated in TC-199 medium containing 5.5 mM glucose, in glucose-deficient medium, and in modified Earle's medium containing 5.5 mM glucose devoid of NaCl, is examined in conjunction with the assessment of lens transparency. Significant age-dependent differences in the phosphorus metabolite profile and in hexosemonophosphate shunt flux, as measured by NMR, were observed in lenses incubated in TC-199 medium containing 5.5 mM glucose. Incubation in glucose-deficient medium for 8 hr results in significant increases in the levels of inorganic phosphate and phosphomonoesters, and decreases in ATP and L-alpha-glycerolphosphate. These levels regain near-normal values after 24 hr incubation in control medium containing 5.5 mM glucose. By contrast, shunt flux is three times the basal level during the recovery period. Lens clarity, as assessed by slit lamp micrography, was maintained throughout the duration of the experiment. Incubation of adult and juvenile lenses for 18 hr in Earle's medium (pH 7.4 or 9.2) containing 5.5 mM glucose, and no NaCl, results in uniform lenticular opacification within 18 hr and changes in ultrastructure of the epithelial and cortical lens fiber cells. No statistically significant change in the NMR visible phosphorus metabolite profile or intralenticular pH is observed for the adult rabbit lens relative to a lens incubated under control conditions. For the juvenile rabbit lens, small, but statistically significant differences in the levels of dinucleotide and uridinediphosphoglucose were observed. Shunt flux, in contrast, is increased two-fold. These results demonstrate that the NMR visible phosphorus metabolite profile of the lens does not necessarily correlate with transparency, and that hexosemonophosphate shunt activity provides a sensitive measure of prior or current lenticular stress.
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PMID:Phosphorus and proton magnetic resonance spectroscopic studies on the relationship between transparency and glucose metabolism in the rabbit lens. 284 77

Rat lenses with experimentally induced cataract (either by naphthalene or by streptozotocin) were analyzed biochemically. Both noxae had some effects in common. Water-soluble protein and aldose reductase activity decreased, and glucose-6-phosphate dehydrogenase, phosphofructokinase and glutathione reductase activity increased. A specific effect of streptozotocin was the rise in glucose, fructose and sorbitol. A specific effect of naphthalene was increased amounts of water-insoluble protein.
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PMID:Alterations of lens metabolism with experimentally induced cataract in rats. 297 80

Three problems were studied on the human and rabbit eye: to what extent the mineralocorticoids contribute to the control of Na+ and K+ transport in the lens epithelium, how do the glucocorticoids influence the concentration of glucose in the aqueous humour and what is the effect of the pituitary-adrenal axis on the hemato-ocular barrier. Specific receptor-like proteins binding aldosterone were found in the lens epithelium. Na+ and K+ concentrations in the aqueous were influenced by both aldosterone and spironolactone administration. The aldosterone concentration in human cataracts was found to be higher in cases of cataracts complicated by arterial hypertension. In spite of some indication of anticataractogenous action of mineralocorticoids, aldosterone did not prevent the formation of cortisol-induced cataract in chick embryos. Glucose concentration in the aqueous was increased by glucocorticoid administration as well as by stimulation of their secretion by ACTH. Further, the contribution of the pituitary-adrenal axis to the breakdown of the hemato-ocular barrier was investigated by measuring the changes of the total protein content in the aqueous. ACTH1-24 caused a partial breakdown of the barrier, as well as ACTH4-10 or alpha-MSH. As the latter two peptides lack the stimulative effect on the corticoid secretion and glucocorticoids themselves fail to increase the protein content in the aqueous, the breakdown of the hemato-ocular barrier seems to be essential for ACTH-linked peptide fragments and is not mediated by corticoids.
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PMID:The role of corticosteroids in the homeostasis of the eye. 300 76

The steady-state kinetics of hydrolysis of Mg2+ ATP by the epithelial Na,K-ATPase of individual human lenses were determined. Among the cataract lens population, four distinct kinetic types were observed: negative kinetic co-operativity. Michaelis-Menten kinetics, positive kinetic co-operativity, and substrate inhibition kinetics. Negative kinetic co-operativity and Michaelis-Menten kinetics were also observed in a group of presumably clear lenses from non-diabetic individuals ages 16-42 years. Substrate inhibition kinetics were found to be prevalent in individuals with mature onset diabetes. Substrate inhibition kinetics were also observed for Na,K-ATPase isolated from lenses which had been incubated in high glucose. It would appear that this modification leads to an inhibition of Na,K-ATPase-dependent K+ influx into these cultured lenses.
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PMID:ATP hydrolysis kinetics of Na,K-ATPase in cataract. 301 82

The activity of the polyol pathway--a non insulin-dependent metabolic pathway of glucose--is increased in diabetic patients. Polyol accumulation is involved, by a myoinositol-dependent mechanism, in the pathogenesis of some degenerative complications of diabetes. Thus, sorbitol accumulation in the eye lens and in nerves seems to be an important factor in the development of cataract and in the slowing down of nerve conduction. Recent studies suggest that the polyol pathway may play a role in early structural abnormalities of retinal and renal microangiopathy. Synthetic aldose reductase inhibitors could be used for a physiopathogenic treatment of these complications, but the first trials in diabetic neuropathy proved disappointing. Further studies, prolonged and well controlled, are necessary to pronounce on the future of this new category of drugs.
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PMID:[Role of the polyol pathway in the occurrence of degenerative complications of diabetes]. 301 8


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