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

In the aetiology and pathogenesis of senile cataract a disturbed glucose utilisation is found. This reflects a loss of activity of some key enzymes for glycolysis in the lens. These enzymes (ALD, G6PDH, HK, LDH, MDH and phosphofructokinase) are zinc metal enzymes. The decrease in activity of these enzymes can be compensated by the administration of specific cations. With zinc one can improve the impaired glucose metabolism occurring in old age. For the prophylaxis and therapy of senile cataract the prolonged administration of zinc aspartate is indicated. In the presence of magnesium deficiency magnesium salts should also be given. Cation eliminating exogenous or endogenous factors must be taken into consideration.
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PMID:[Clinical biochemical aspects of the prophylaxis and therapy of senile cataract with zinc aspartate (author's transl)]. 9 66

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

We determined the activity level of glucose 6-phosphate dehydrogenase in 467 patients with cataract from northern Sardinia. Of 226 men, 18 (8%) had glucose 6-phosphate dehydrogenase deficiency. Of 241 women, 30 (12%) were heterozygous and two (1%) were homozygous for glucose 6-phosphate dehydrogenase deficiency. These prevalences were not significantly different from those expected in the general population. We concluded that patients with glucose 6-phosphate dehydrogenase deficiency do not have a higher risk of developing cataract.
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PMID:Glucose 6-phosphate dehydrogenase deficiency and cataract of patients in northern Sardinia. 224 31

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

A possible correlation between development of cataract and glucose 6-phosphate dehydrogenase (G6PD) deficiency in red blood cells and lenses was investigated. The distribution of cataract types in both G6PD-positive and G6PD-deficient patients, the incidence of G6PD deficiency in cortical cataract groups and the distribution of G6PD-deficient cases according to age were determined. The results showed that quite a high percentage of cortical cataractous patients had G6PD deficiency in both red blood cells and lenses.
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PMID:Glucose 6-phosphate dehydrogenase deficiency both in red blood cells and lenses of the normal and cataractous native population of Cukurova, the southern part of Turkey. Part II. 278 55

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


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