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Query: UMLS:C0086543 (cataract)
 29,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Risk factors and course of steroid diabetes were investigated in 145 renal-transplant recipients who were given a high-dose steroid regimen. Persistent steroid diabetes developed in 25% of the patients and transient diabetes in another 22%. When antidiabetic therapy was required, insulin had to be given in 50%. The incidence of steroid diabetes correlated with steroid dose, age, body weight, and diabetes heredity but not with abnormal glucose tolerance or with another complication of steroid therapy, posterior-pole lenticular cataract. There was no association with HLA-A and B antigens. Thus, steroid diabetes is a frequent complication of high-dose corticosteroid therapy and is similar to type II diabetes. However, it often requires insulin therapy.
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PMID:Some characteristics of steroid diabetes: a study in renal-transplant recipients receiving high-dose corticosteroid therapy. 634 Oct 13

Levels of lens aldose reductase, aldehyde dehydrogenase activity, and erythrocyte NADPH-oxidising (or glyceraldehyde reductase) activity were determined in 17 diabetic and 16 nondiabetic patients undergoing cataract extraction. Lens aldose reductase and aldehyde dehydrogenase activities were significantly lower in diabetics than in nondiabetics. Both enzymes showed significant inverse correlations with grouped HbA1c and fasting blood glucose levels. By contrast, erythrocyte NADPH-oxidising activity showed a significant positive correlation with grouped HbA1C. It is suggested that a direct effect of the glycaemic status on the lens enzymes is masked by a loss of enzymes secondary to the development of cataract. It is not yet possible to say whether erythrocyte NADPH-oxidising activity can be used to monitor aldose reductase activity in the lens or other tissues in clinical trials of aldose reductase inhibitors.
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PMID:NADPH-oxidising activity in lens and erythrocytes in diabetic and nondiabetic patients with cataract. 641 39

Sorbitol, resulting from glucose metabolism through aldose reductase, may play a role in diabetic complications such as cataracts, neuropathy, and vasculopathy. Sulindac (Clinoril) and sorbinil, two inhibitors of aldose reductase, decreased sorbitol formation in cataract or nerve tissue incubated in high glucose TC-199 media. Sulindac, a widely used anti-rheumatic drug, may have clinical applications in preventing diabetic complications.
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PMID:Diabetic complications in lens and nerve and their prevention by sulindac or sorbinil: two novel aldose reductase inhibitors. 641 48

An increased prevalence of cataract is associated with diabetes. Biochemical studies of diabetic lenses have revealed a variety of metabolic abnormalities including changes in the levels of electrolytes, glutathione, nucleotides and sugars. Similar biochemical changes have also been observed in cataracts associated with galactosaemia, suggesting that these sugar cataracts have a common biochemical aetiology. The common biochemical factor found to initiate both types of sugar cataract is the formation of sugar alcohols (polyols) from either glucose or galactose by the enzyme aldose reductase (alditol: NADP+ 1-oxidoreductase, EC 1.1.1.21). Increased intracellular levels of these polar alcohols have a hyperosmotic effect which leads to lens fibre swelling, vacuole formation and subsequent opacification. The process of sugar cataract formation in animals can be prevented by inhibiting aldose reductase.
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PMID:Diabetic and galactosaemic cataracts. 643 98

Assay of the activities of hexokinase, phosphofructokinase, and pyruvate kinase showed that the first two declined in aging human lens cortex and all three enzymes retained constant activities in the epithelium throughout life. Moreover, both clear and cataractous aging lenses contained the same enzyme activities. ATP contents in cataracts, however, were lower than in clear lenses; in fact, after incubation at 37.5 degrees C in isotonic (290 to 300 mOsm), glucose-containing media, ATP was rapidly lost from cataracts (but not from clear lenses), suggesting excessive ATP expenditure in cataracts for osmotic balance. Cataracts incubated in media containing either glucose-6-phosphate or fructose-1, 6-diphosphate produced significantly higher ATP than with glucose in the media, indicating that glucose metabolism in human senile cataracts could be supplemented with hexose phosphates. Fructose-1, 6-diphosphate appeared to be more efficient than glucose-6-phosphate in preventing lens swelling during incubation.
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PMID:Supplementing glucose metabolism in human senile cataracts. 645 78

The overall prevalences of microvascular complications and their association with dietary, clinical, and metabolic characteristics have been studied in 503 Mexican type II diabetic subjects. Average daily dietary intakes were 1866 kcal, 46.5% as carbohydrate, 13.7 mmol cholesterol, 8.7 g fiber, and a polyunsaturated/saturated fat ratio of 0.98. Prevalence rates of microvascular and metabolic complications were as follows: background retinopathy 12.3%, exudative retinopathy 24.2%, proliferative retinopathy 8.1% (1% blind, 4% able to read large print only), 9.1% of patients had cataract, 15.9% nephropathy, and 40.8% peripheral neuropathy. In addition, 3.6% had experienced transient lower motor neuron facial paralysis and 0.2% oculomotor paralysis. Patients with retinopathy had a longer mean duration of diabetes, were less obese at the time of examination, and had higher initial and mean blood pressures and higher mean fasting blood glucose levels when compared with those without retinopathy. Similar differences were observed between groups with and without nephropathy except that mean blood glucose levels were similar in the two groups. The presence of peripheral neuropathy was associated with longer duration of diabetes, less obesity, higher mean blood pressure and mean blood glucose levels, and lower hemoglobin concentration. Patients treated with diet alone had significantly lower prevalences of all three microvascular complications but they also had significantly shorter duration of diabetes and lower mean blood glucose levels. However, multivariate analyses on the subgroup of 360 patients who had repeated fasting blood glucose measurements for at least 5 yr demonstrated associations between retinopathy and duration of diabetes, mean blood pressure and mean blood glucose, and percent calories from carbohydrate.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Association of differing dietary, metabolic, and clinical risk factors with microvascular complications of diabetes: a prevalence study of 503 Mexican type II diabetic subjects. II. 649 36

The glucose concentrations of the blood plasma and aqueous humour were measured in 56 cataract patients. The sodium concentration and colour of the lenses were determined after extraction. The mean plasma and aqueous glucose levels were 5.8 and 3.2 mM respectively in non-diabetic patients, while the values for diabetics were 14.2 and 7.8 mM. The sodium concentration of the lenses from non-diabetic patients appeared to consist of two distributions around 30 and 170 mM, corresponding to nuclear and cortical cataracts respectively. Only two lenses from the non-diabetic patients had sodium concentrations in the range 60-120 mM. In diabetic patients, however, 80% of the extracted lenses had sodium concentrations in this intermediate range. The data indicate that the osmotic stresses induced in the lenses of diabetic and non-diabetic patients are different. The diabetic lenses were also distributed in the middle range when nuclear colour was graded on a scale from I to V, while normal lenses were again normally distributed at either end of the scale.
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PMID:Aqueous humour glucose concentration in cataract patients and its effect on the lens. 651 97

The mammalian lens contains an unusually high concentration of glutathione (GSH), the highest level being in the epithelium. GSH is present largely in the reduced state. The high concentration of GSH in a normal lens and the decreased concentration in most types of cataracts have led to many hypotheses on its role in cataract formation. These hypotheses are considered in the light of current evidence. GSH is synthesized and degraded in the lens. Both processes require ATP, derived largely from glycolysis. Carbohydrate metabolism is also involved in the maintenance of GSH in the reduced state. There is a direct link between the rate of formation of oxidized glutathione (GSSG) and the stimulation of the hexose monophosphate shunt through the generation of NADPH. One possible function of GSH in the lens is to maintain the thiol (SH) groups of proteins in the reduced state, thus preventing formation of high molecular weight (HMW) protein aggregates. The formation of HMW proteins in X-ray-induced cataracts through disulphide bond formation and the involvement of SH oxidation in HMW proteins isolated from human cataractous lenses suggest a role for GSH in protecting protein SH groups. GSH in the lens may also protect critical SH groups involved in regulating cation transport and permeability. Studies with mammalian lenses indicate that lowering the lens GSH concentration leads to increased permeability to cations and inactivation of Na+,K+-ATPase. A consequence of the changes in ion distribution is the inhibition of protein synthesis, which may explain the cessation of growth in cataractous lenses. GSH may also protect against oxidative damage to the lens. GSH metabolism is intimately involved in detoxification of H2O2, normally present in the aqueous humour. Lenses with impaired shunt activity or inhibited glutathione reductase are more susceptible to oxidative damage by peroxide. This may contribute to the formation of cataract.
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PMID:Metabolism and function of glutathione in the lens. 656 81

Association of "senile" cataract (SC) with glucose intolerance (impaired tolerance and diabetes) was assessed by sex and age in a random population sample comprising 930 individuals aged 40-70 yr, who underwent concurrent oral glucose tolerance test and ophthalmoscopy. The eye examination was performed without knowledge of the glucose tolerance status. SC was defined as lens opacification preventing visualization of the eyeground or as surgical aphakia due to SC. To assess the independent effect of hyperglycemia, glycosylated hemoglobin (HbA1) was determined in 769 participants. In men, no association was found between SC, glucose intolerance, and HbA1. In women of all ages, glucose intolerance was associated with an SC risk ratio of 6.1 (95% confidence limits 3.3-11.1; P less than 0.001). Furthermore, SC was associated in women with increased HbA1 independently of the effect of glucose intolerance (P less than 0.01). These findings confirm the reported association of SC with diabetes (although unlike the Framingham and HANES population studies, the association was confined in women), indicate its presence at all degrees of glucose intolerance, and suggest a possible independent role of nonenzymatic glycosylation in its pathogenesis.
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PMID:Senile cataract and glucose intolerance: the Israel Study of glucose Intolerance Obesity and Hypertension (The Israel GOH Study). 670 65

Flavonoids are known as potent inhibitors of aldose reductase, an enzyme that may initiate cataract formation in diabetes. We have tested the inhibitory activity of new flavone derivatives on a homogenate of lens epithelium. Compounds which inhibited the enzyme activity by more than 50 percent at 10(-60) M were then tested on rat lenses perfused in a 0.027 M glucose solution. Our preliminary studies indicate that these new flavone derivatives can prevent or delay the formation of cataract in an in-vitro model.
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PMID:[Aldose-reductase inhibitors and cataract formation (author's transl)]. 677 30


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