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)

Experimental work in our laboratory has confirmed the protective activity of vanadium compounds on hyperglycemia and glycosuria in streptozotocin (STZ) diabetes. Furthermore, diabetic cataract has also been partially prevented. Nevertheless, the combination of a natural antioxidant, vitamin E, with Na3 VO4 has not further enhanced this ameliorating effect. Our experimental approach has been an attempt to block the prooxidant activity of both STZ and vanadate, with the purpose of eliciting the best possible antidiabetic protection. More recently, a lipid soluble synthetic antioxidant U-78517F, a 2-methylaminochroman, has been reported to have a significant protective effect against brain injury and ischemia. This compound inhibits the iron-dependent lipid peroxidation 100 times more effectively than vitamin E. This investigation has introduced a combination of the vanadium compound plus the aforesaid lazaroid, as its (-) enantiomer, U-83836E, in order to improve the insufficient protection when vitamin E was used. For twelve weeks, male Wistar rats, rendered diabetic with STZ, were administered Na3VO4 in drinking water along with the lazaroid carried by the food. Four, eight and twelve weeks after the beginning of the protective treatment, fluid and food intake, diuresis and excreted feces, glycosuria and proteinuria were determined on biological samples obtained in metabolic cages; body weight and glycemia were also recorded. At weeks 6 and 12 of the treatment, the opaqueness of the eye lenses was controlled and registered. At the end of the experiment, circulating glycosylated hemoglobin (HbA1c), fructosamine, N-acetyl-beta-D-glucosaminidase (NAG), and fluorescent peroxides were evaluated. Within the first month of treatment, protection by the combination paralleled that elicited by vanadate alone. At subsequent steps, U-83836E significantly improved the protective effect of vanadate alone on polydipsia and polyuria, but especially on hyperglycemia and glycosuria. The further ameliorating effect of the lazaroid was also observed on HbA1c and NAG, and, most important, on the cataract. In conclusion, these findings demonstrate that the lazaroid U-83836E succeeds in further protecting the most important symptoms of diabetes treated with vanadate, and that this antioxidant acts effectively even when it is administered orally in food, in a non invasive manner.
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PMID:Amelioration of diabetes and cataract by Na3VO4 plus U-83836E in streptozotocin treated rats. 782 6

The activities of glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-R), superoxide dismutase (SOD) and the contents of malondialdehyde (MDA) and free radicals were measured, and the morphological changes were observed in the lens of control rats, selenium-deficient (SeD) and/or vitamin E deficient (VED) rats. The activities of GSH-Px in the lens of SeD rats decreased significantly. The GSH-Px activities of lens were positively related to erythrocytes selenium level. There was a free radical at g = 2.0015 in the rat lens of all groups, but the content of free radicals in the lens of SeD group was significantly higher than that of the control group. The free radical content of lens was negatively related to erythrocytes selenium level, as well as the GSH-Px activities in the lens. In vitro, ultraviolet radiation caused the generation of another kind of free radical (g = 2.0097) in the lens of all groups, but the amount of the free radical in the lens of the SeD group was also significantly higher than that of the control group. The activities of SOD and GSSG-R in VED rat lens were significantly decreased. The amount of MDA in the lens of SeD and/or VED rats were significantly increased. The results showed that the decrease of antioxidative capability in the lenses of SeD and/or VED rats accelerated the lipid peroxidation and generation of free radicals. Although only early morphological changes in SeD and/or VED rat lens were observed, it is considered that selenium and vitamin E deficiency may be involved in the occurrence of cataract.
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PMID:Biochemical and morphological changes in the lenses of selenium and/or vitamin E deficient rats. 794 5

A better understanding of the functions of ascorbic acid would help clarify the magnitude of the influence of this vitamin on health-related conditions. Many of the purported benefits require confirmation as well as a knowledge of the mechanism of action. The majority of investigations of the association of vitamin C with various types of cancer, with cardiovascular risk, and with cataract formation were epidemiologic studies. Often it was not possible to discern whether the apparent protective effect was due to vitamin C, vitamin E, or carotene, or to a combined effect of these nutrients or of additional factors. Human intervention trials may provide definitive and quantitative assessments of the role of vitamin C in health maintenance. We need to gain a more thorough understanding of the interactions of vitamin C with other nutrients, such as vitamin E and carotenoids, in order to appreciate the role of vitamin C in disease prevention. Investigators are increasingly recognizing the diverse functions of vitamin C in the body in addition to its role in collagen synthesis. However, the functional consequences of these many important roles of vitamin C remain essentially unknown. Excluding scurvy, the health consequences of inadequate vitamin C status are not well characterized. Nonetheless, epidemiologic evidence suggests a role for vitamin C in cancer and heart disease as well as in a number of other diseases.
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PMID:Pharmacology of vitamin C. 794 25

The development of drugs in order to block metabolic pathway of glucose responsible for diabetic vascular dysfunction is in progress. Aldose reductase inhibitors prevent or reduce the different components of vascular dysfunction, cataract, neuropathy and nephropathy in animal models of diabetes. Promising results have been observed in diabetic patients concerning the prevention of neuropathy and of retinopathy. Larger scale studies with the second generation compounds are in progress. Glycation inhibitors, mainly aminoguanidine, have been shown to prevent or reduce vascular dysfunction and microvascular complications in animal models. Trials in diabetic patients with aminoguanidine are just beginning. Anti-oxidant therapy is also at its early stage of development (vitamin E, vitamin C, alpha lipoic acid). Antiplatelet agents (aspirin, ticlopidine) have been demonstrated to reduce the progression of non proliferative diabetic retinopathy. Angiotensin converting enzyme inhibitors are of particular interest in preventing diabetic glomerulopathy.
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PMID:[Preventive treatment of diabetic microangiopathy: blocking the pathogenic mechanisms]. 800 9

Despite a realisation that antioxidants will not delay ageing in healthy older people, there is increasing scientific interest in the role of free radical oxidants in a number of diseases associated with older age. For most of these diseases there is suggestive theoretical and laboratory evidence but not confirmatory clinical evidence. Free radical damage seems likely to be significant in the pathophysiology of atherosclerosis, ischaemia-reperfusion injury, Parkinson's disease, cataract, some cancers and rheumatoid arthritis. Evidence to suggest a protective effect from antioxidant vitamins exists for ischaemic heart disease, cataract and some cancers. Attempts to influence the outcome of other diseases such as ischaemia-reperfusion injury, Parkinson's disease and rheumatoid arthritis have so far failed to achieve positive results. Research interest in the field is increasing although hampered by methodological difficulties and the limited financial return for drug companies. In the meantime there seems no reason to discourage older people who wish to ingest extra vitamin E and vitamin C. A diet with adequate vegetables and fruits should provide sufficient beta carotene.
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PMID:Free radicals, antioxidants and preventive geriatrics. 806 Feb 75

Emory mouse cataracts were analyzed for amino acids, protein carbonyls and fatty acids. The tissue membrane integrity was assessed by studying chromium-51 efflux. An effect of vitamin E-free diet on cataract progression was also studied. Chromium leakage was faster from the cataractous lenses, indicating a generalized membrane damage. This was also apparent from the loss of amino acids. The damage involves oxidation of proteins, as well as of lipids. Protein oxidation was apparent by a hydrazone formation with 2,4-dinitrophenyl hydrazine. The lipid oxidation was apparent from a decrease in oleic acid and appearance of the corresponding ketoacids. Lipid oxidation was also apparent by an attenuating effect of vitamin E.
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PMID:Studies on Emory mouse cataracts: oxidative factors. 809 Apr 31

To examine whether vitamin/mineral supplementation may lower mortality and incidence from human cancer and mortality from other diseases as well as to provide the scientific basis and feasible approach for human cancer prevention and control, between 1982-1991 scientists from China and USA conducted two randomized, double-blind, and placebo-controlled nutrition intervention trials in Linxian, China, where the esophageal/gastric cardia cancer mortality rates are among the highest in the world and there is suspicion that the population's chronic deficiencies of multiple nutrients are etiologically involved. In the first trial, the Dysplasia Trial, 3,318 individuals with a cytologic diagnosis of esophageal dysplasia received daily 26 vitamin/mineral supplements or placebos for 6 years; The second trial, the General Population Trial, involved 29,584 individuals and used an one-half replicate of a 2(4) fractional factorial design which randomized to 8 groups for testing the effects of daily supplementation of 4 different vitamin/mineral combinations and placebo for a period of 5 1/4 years. Compliance assessed by monthly pill counts and quarterly monitoring of biochemical assays indicated that the participant compliance was excellent. As endpoints of the trials, incident cancers and deaths were identified through all medical facilities in local areas, supplemented by special endoscopy and cytology examinations, and confirmed by 3-level review groups. A total of 323 deaths occurred during 6 year period among participants in the dysplasia trial, and 2,127 deaths from the general population trial during 5 1/4 years. Besides, an eye examination, which included detailed lens evaluations, was included in the extensive re-examination protocol to ascertain whether use of the supplements had affected the risk of developing age-related cataracts among participants in the two trials. Results from Dysplasia Trial indicated that after 6 years of daily supplementation with multiple vitamins and minerals, total mortality among those in the active treatment group was slightly (9%) lower than in the placebo group; and deaths of esophageal cancer also declined by 17%, as well as a sizeable reduction in cerebrovascular disease mortality (near 40%) was seen, though none was statistically significant. However, intervention had decreased prevalence of eye nuclear cataract (43%) (P < 0.01). The findings from the General Population Trial provide support for the hypothesis that intake of specific micronutrients may inhibit cancer development. Significant reduction of total mortality (9%), cancer mortality (13%), gastric cancer mortality (20%), and mortality of the other cancers (19%) occurred among those receiving beta-carotene/vitamin E/selenium supplementation (P < 0.05). Patterns of cancer incidence, based on 1307 cases, generally resembled those for cancer mortality.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Preliminary report on the results of nutrition prevention trials of cancer and other common diseases among residents in Linxian, China]. 826 60

The pineal hormone melatonin exhibits remarkable functional versatility. Shortly after its discovery, melatonin was functionally linked to the regulation of the neuroendocrine axis, particularly to the reproductive system. However, judging from the wide variety of cellular changes that occurred following either pinealectomy, to remove the primary source of melatonin, or the exogenous administration of the indole, it was obvious that the activity of melatonin far transcended its actions on the hypothalamo-pituitary-gonadal system. Roughly 30 months ago it was discovered that melatonin is a highly efficient free radical scavenger and general antioxidant. This implied that melatonin, which is both lipophilic and hydrophilic, has effects not only in every cell but also within every subcellular compartment. These intracellular actions of melatonin, some of which are independent of any receptor interaction and some of which are mediated by nuclear receptors, have become the focus of much of the current investigation. As an antioxidant, melatonin has been shown in vitro to be a highly efficient scavenger of the very reactive and toxic hydroxyl radical. Indeed, on an equimolar basis melatonin proved significantly more efficient in neutralizing the hydroxyl radical than did the two well-known scavengers, glutathione and mannitol. Likewise, melatonin was found to also scavenge the peroxyl radical which is generated during lipid peroxidation; in this regard it was roughly twice as effective as vitamin E (alpha-tocopherol). The antioxidant activities of melatonin have been well documented in tissue homogenates and organisms as well. When rats are treated with the chemical carcinogen safrole, this agent induces the generation of free radicals which in turn extensively damage nuclear DNA; this damage is almost totally eliminated if the animals are cotreated with melatonin. Also, damage to DNA in human lymphocytes due to ionizing radiation, another treatment which is known to induce free radical formation, is greatly reduced if the cells are treated with melatonin prior to radiation. Cytosolic protein seems also to be protected from free radical damage when melatonin is present. When newborn rats are treated with a glutathione-depleting drug at birth, by 2 weeks of age the animals have cataracts. Cataracts form because oxidants damage protein in the presence of low intracellular levels of glutathione. Cataracts induced by this means are essentially prevented if the glutathione-depleted rats are supplemented with melatonin. Finally, membrane lipid peroxidation, induced either in vivo or in vitro by any of several means, all of which involve free radicals, is drastically attenuated in the presence of melatonin. Considering melatonin's ability to cross all morphophysiological barriers and to enter every cell, and all subcellular compartments, the implication is that this indole may play a very important role in the antioxidative defense system of the organism. These findings potentially have important implications for a wide variety of age-related diseases and to aging itself. Melatonin's control of reproductive physiology in photoperiodic mammals is well documented. However, the site of interaction of melatonin with the neuroendocrine axis has been especially difficult to determine. The discovery and cloning of a membrane melatonin receptor on neurosecretory cells in the hypothalamus and on hormone secreting cells of the anterior pituitary gland stimulated a great deal of investigation which has failed to prove the involvement of these receptors in the processes by which melatonin influences reproductive physiology. The recent identification of nuclear melatonin receptors as well as the nonreceptor-mediated actions of the indole are currently being examined as to their association with reproductive function.
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PMID:Functional pleiotropy of the neurohormone melatonin: antioxidant protection and neuroendocrine regulation. 855 71

This study revealed a marked stereospecificity in the prevention of buthionine sulfoximine-induced cataract, and in the protection of lens antioxidants, in newborn rats by alpha-lipoate, R- and racemic alpha-lipoate decreased cataract formation from 100% (buthionine sulfoximine only) to 55% (buthionine sulfoximine + R-alpha-lipoic acid) and 40% (buthionine sulfoximine + rac-alpha-lipoic acid) (p<0.05 compared to buthionine sulfoximine only). S-alpha-lipoic acid had no effect on cataract formation induced by buthionine sulfoximine. The lens antioxidants glutathione, ascorbate, and vitamin E were depleted to 45, 62, and 23% of control levels, respectively, by buthionine sulfoximine treatment, but were maintained at 84-97% of control levels when R-alpha-lipoic acid or rac-alpha-lipoic acid were administered with buthionine sulfoximine; S-alpha-lipoic acid administration had no protective effect on lens antioxidants. When enantiomers of alpha-lipoic acid were administered to animals, R-alpha-lipoic acid was taken up by lens and reached concentrations 2- to 7-fold greater than those of S-alpha-lipoic acid, with rac-alpha-lipoic acid reaching levels midway between the R-isomer and racemic form. Reduced lipoic acid, dihydrolipoic acid, reached the highest levels in lens of the rac-alpha-lipoic acid-treated animals and the lowest levels in S-alpha-lipoic acid-treated animals. These results indicate that the protective effects of alpha-lipoic acid against buthionine sulfoximine-induced cataract are probably due to its protective effects on lens antioxidants, and that the stereospecificity exhibited is due to selective uptake and reduction of R-alpha-lipoic acid by lens cells.
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PMID:Stereospecific effects of R-lipoic acid on buthionine sulfoximine-induced cataract formation in newborn rats. 861 71

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


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