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)

Studies have been made of the effects of X-ray on various lens reducing systems, including the levels of NADPH and glutathione (GSH), the activity of the hexose monophosphate shunt (HMS) and of certain enzymes, including GSH reductase, GSH peroxidase, and glucose-6-phosphate dehydrogenase (G-6-PG). It was found that during several weeks following X-irradiation but prior to cataract formation, there was very little change in the number of reduced -SH groups per unit weight of lens protein but that, with the appearance of cataract, there was a sudden loss of protein -SH groups. In contrast, the concentration of GSH in the X-rayed lens decreased throughout the experimental period. Similarly, the concentration of NADPH in the X-rayed lens was found to decrease significantly relative to controls 1 week prior to cataract formation, and the ratio of NADPH to NADP+ in the lens shifted at this time period from a value greater than 1.0 in the control lens to less than 1.0 in the X-rayed lens. A corresponding decrease occurred in the activity of the HMS in X-rayed lenses as measured by culture in the presence of 1-14C-labeled glucose, G-6-PD was partially inactivated in the X-rayed lens. Of the eight enzymes studied, G-6-PD appeared to be the most sensitive to X-irradiation. The data indicate that X-irradiation results in a steady decrease in the effectiveness of lens reducing systems and that when these systems reach a critically low point, sudden oxidation of protein -SH groups and formation of high-molecular-weight protein aggregates may be initiated.
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PMID:The effects of X-irradiation on lens reducing systems. 3 84

A total of 1,008 cases and 469 controls, aged 45-79 years, were included in a clinic-based case-control study of age-related cataract in Parma, Italy, from 1987 to 1989. Associations were examined between specific types of cataract and physiologic, behavioral, environmental, and biochemical factors. Cases included subjects with pure cortical (n = 489), pure nuclear (n = 110), pure posterior subcapsular (n = 28), and mixed (n = 381) cataracts. With polychotomous logistic regression, an increased risk of cataract was found for females (cortical; odds ratio (OR) = 2.20) and persons with less than a high school education (all types; OR = 1.53), brown irises (nuclear, mixed; OR = 1.43), job locations in the sunlight (cortical, mixed; OR = 1.75), leisure time activities in the sunlight (cortical, mixed; OR = 1.45), a history of wearing a hat in summertime (posterior subcapsular, cortical, mixed; OR = 1.80), a positive family history of cataract (posterior subcapsular, cortical, mixed; OR = 1.88), a history of cortisone use (posterior subcapsular; OR = 8.39), increased red blood cell glucose-6-phosphate dehydrogenase activity (cortical, nuclear, mixed; OR = 1.36), and increased serum levels of uric acid (posterior subcapsular; OR = 1.62), lactic dehydrogenase (posterior subcapsular; OR = 1.76) and gamma-glutamyl transpeptidase (mixed; OR = 1.22). A decreased risk of cataract was found for persons with a positive history of arthritis (posterior subcapsular, nuclear, mixed; OR = 0.56) and increased handgrip strength (mixed; OR = 0.68). Findings from our study, combined with previously reported evidence, suggest that associations with educational status, cortisone use, sunlight exposure, and handgrip strength are real. Other findings require further evaluation.
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PMID:Risk factors for age-related cortical, nuclear, and posterior subcapsular cataracts. The Italian-American Cataract Study Group. 167 83

Many reports have pointed out that oxidative damage and disturbances in antioxidant defense systems of the lenses may play an important role in the development of cataract. In the present study the activities of glutathione peroxidase, glutathione reductase, glutathione-S-transferase, glucose-6-phosphate dehydrogenase, catalase and the level of glutathione and lipid peroxides were measured in red blood cells of galactosaemic children with cataract and without cataract. Furthermore the serum antioxidant activity and the level of uric acid. ceruloplasmin and transferrin in serum were estimated. It was found that in red blood cells of galactosaemic children with cataract the activity of glutathione reductase was slightly lower than in a control age-matched group of children and in galactosaemic children without cataract. The increase of serum antioxidant activity in both groups of galactosaemic children was also observed. Probably it could be due to the increase of the level of ceruloplasmin. Except glutathione reductase activity no other differences were found in the investigated components of the antioxidant defense systems of red blood cells and serum between galactosaemic children with cataract and those without cataract. Therefore it seems that red blood cells and serum metabolism are no good reflections of disturbances in antioxidant defense mechanisms which may be involved in the cataract development in galactosaemic children.
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PMID:Red blood cells and serum antioxidant defense systems of galactosaemic children. 208 Sep 1

Erythrocytic glucose-6-phosphate dehydrogenase (G-6-PD) was tested in 163 cases of senile cataract and 79 age- and sex-matched controls. There was no statistically significant difference between the overall incidence of G-6-PD deficiency in cataract in comparison to controls. However, amongst the cataract patients the frequency of G-6-PD deficiency was significantly higher in the age group 40 to 50 years (12.1%) as compared to those aged 51 years or more.
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PMID:Senile cataract and glucose-6-phosphate dehydrogenase deficiency in Indians. 210 77

In this study we have investigated the oxidative metabolism of red cells (RBC), plasma, serum and aqueous humour of healthy subjects and of age-matched cataractous patients with and without chronic renal failure (CRF). Reduced glutathione (GSH) levels in RBC were lower in CRF patients than in the other groups. Oxidized glutathione (GSSG) plasma levels in CRF patients were higher than those of controls and cataractous subjects. The activity of the enzyme glucose-6-phosphate dehydrogenase in RBC was significantly reduced in CRF patients with respect to the other two groups. The levels of malondialdehyde (MDA) in RBC and in lens were about twice in CRF patients compared with the other two groups. The plasma levels of vitamin E were diminished in CRF patients; on the contrary, the biological liquid oxidant activity (BLOA) of serum in CRF patients was significantly higher than in controls and in cataractous patients without CRF. Cataractous patients with and without CRF showed similar levels of GSH in aqueous humour; on the contrary, the content of GSSG was significantly higher in CRF patients. Our findings seem to demonstrate that CRF patients are exposed to oxidative stresses that could probably act synergistically with uraemia and carbamylation of lens proteins. This synergism could explain why CRF represents a relatively high risk factor for cataract.
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PMID:Systemic human diseases as oxidative risk factors in cataractogenesis. II. Chronic renal failure. 226 73

Linkage data relative to the markers tabby and glucose-6-phosphate dehydrogenase are presented to locate X-linked cataract (Xcat) in the distal portion of the mouse X-chromosome between jimpy and hypophosphatemia. The human X-linked cataract-dental syndrome, Nance-Horan Syndrome, also maps closely to human hypophosphatemia and would suggest homology between mouse Xcat and human Nance-Horan Syndrome genes. In hemizygous males and homozygous females penetrance is complete with only slight variation in the degree of expression. Phenotypic expression in Xcat heterozygous females ranges from totally clear to totally opaque lenses. The phenotypic expression between the two lenses of a heterozygous individual could also vary between totally clear and totally opaque lenses. However, a correlation in the degree of expression between the eyes of an individual was observed. A variegated pattern of lens opacity was evident in female heterozygotes. Based on these observations, the site of gene action for the Xcat locus is suggested to be endogenous to the lens cells and the precursor cell population of the lens is concluded to be small. The identification of an X-linked cataract locus is an important contribution to the estimate of the number of mutable loci resulting in cataract, an estimate required so that dominant cataract mutagenesis results may be expressed on a per locus basis. The Xcat mutation may be a useful marker for a distal region of the mouse X-chromosome which is relatively sparsely marked and the X-linked cataract mutation may be employed in gene expression and lens development studies.
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PMID:Genetic localization and phenotypic expression of X-linked cataract (Xcat) in Mus musculus. 227 5

In a hospital-based case-control study of 1441 patients with age-related cataracts and 549 controls, we studied associations between types of cataract--nuclear, cortical, posterior subcapsular, and mixed--and a number of physiologic, behavioral, environmental, and biochemical variables. Using polychotomous logistic regression analysis, we found an increased risk of cataract with lower educational achievement (all types of cataract), decreased cloud cover at place of residence (all types), use of aspirin less than once a month (posterior subcapsular and mixed), diets low in selected nutrients (posterior subcapsular, nuclear, and mixed), higher blood pressure (nuclear and mixed), lower body mass index (nuclear and mixed), use of cheaper cooking fuels (cortical, nuclear, and mixed), and lower levels of an antioxidant index based on red blood cell levels of glutathione peroxidase and glucose-6-phosphate dehydrogenase and plasma levels of ascorbic acid and vitamin E (posterior subcapsular and mixed). All risks cited were significantly different from those for the other cataract types, a finding that emphasizes the need to investigate the epidemiology of specific types of cataract.
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PMID:India-US case-control study of age-related cataracts. India-US Case-Control Study Group. 229 22

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

In this study we have investigated the oxidative metabolism of red blood cells (RBC), plasma, serum, aqueous humor, and lens of healthy subjects and of age-matched cataractous patients with and without diabetes. Reduced and oxidized glutathione (GSH GSSG) levels in RBC were similar among the three groups. Plasma levels of GSSG were higher in diabetics than in cataractous and control subjects. No differences in plasma content of GSH were noted among the three groups. The activity of the enzyme glucose-6-phosphate dehydrogenase was significantly diminished in diabetic patients. Controls and cataractous patients showed similar levels of malondialdehyde (MDA). Although not significant the MDA content in RBC from diabetics was elevated. No differences in plasma levels of vitamin E were noted among the three groups. The biological liquid oxidant activity of serum in diabetic patients was significantly higher than in controls and cataractous patients. GSH levels in aqueous humor were similar in diabetic and nondiabetic cataractous patients. The content of GSSG in aqueous humor was highest in diabetic patients. Control clear lenses showed low levels of MDA. The MDA levels in cataractous lenses from nondiabetic patients were significantly higher than those of controls. In diabetic patients the content of MDA in the lens was approximately twice as high as the cataractous values. Our results seem to demonstrate that oxidative damage could play a role in the pathogenesis of cataract in diabetes.
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PMID:Systemic human diseases as oxidative risk factors in cataractogenesis. I. Diabetes. 318 3

The relationship between biochemical markers of antioxidant status and senile cataract was examined in 112 subjects aged 40 to 70 years. Seventy-seven of these subjects had a cataract in at least one lens. Antioxidant status was measured using erythrocyte superoxide dismutase, glutathione peroxidase, and glucose-6-phosphate dehydrogenase activity, and indexes that included these enzymes plus plasma levels of vitamin E, vitamin C, and carotenoids. Subjects were grouped by level (low, moderate, or high) of the enzymes and antioxidant indexes. Results suggest that subjects with high levels of at least two of the three vitamins (vitamin E, vitamin C, or carotenoids) are at reduced risk of cataract relative to subjects with low levels of one or more of these vitamins (odds ratio, 0.2). The erythrocyte enzymes, either individually or in combination, did not appear to differ between subjects with and without cataract.
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PMID:Antioxidant status in persons with and without senile cataract. 334 51


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