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 diabetic and galactosemic animal models are widely used to study diabetes-induced complications. Galactose feeding can rapidly produce cataract, retinopathy and nephropathy; it is therefore favored over the diabetic model. Although the common feature for both models is the activation of aldose reductase, there are substantial differences between the two--not only does the rate of cataract progression differ but the metabolic patterns are far more complex than for polyol production alone. We here present the result of a comparison between diabetic and galactosemic lenses and show the differences in phosphorus and aldose metabolism, cell integrity and osmotic environment.
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PMID:Metabolic studies of galactosemic cataract. 220 47

Galactose, and the phosphorothioates, WR-77913 and WR-2721, which inhibit cataract produced by X-irradiation, were evaluated for their effects on the phase separation temperature, Tc, of calf lens homogenate. The reagents were added to nuclear homogenate and the change in Tc per mol, dTc/dC, was measured. Galactose decreased Tc, -65 degrees C mol-1, WR-77913 decreased Tc, -28 degrees C mol-1 and WR-2721 decreased Tc, -76 degrees C mol-1. These are the first phase separation inhibitors that can be used in vivo to study the inhibition of lens opacification.
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PMID:Inhibition of phase separation by reagents that prevent X-irradiation cataract in vivo. 282 97

There are conflicting reports in the literature regarding the role of partial deficiency of "galactosemic" enzymes (galactose-1-P-urydil transferase and galactokinase) in the development of infantile and presenile cataract. The AA. have investigated the levels of Red Blood Cell Galactose-1-P-urydil transferase in 39 cataractous patients and in 22 age matched controls. A weak correlation between the enzymatic activity deficiency and the presenile cataract has been identified. The results suggest that a chronic impairment of galactose metabolism may be a contributory risk factor in the pathogenesis of presenile cataracts; however, further investigations are required to assess the actual significance of the findings of the present paper.
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PMID:Red blood cells galactose-1-P-urydil transferase in senile and presenile cataracts. 283 94

The effect of sodium iodate injection on the development of galactose cataract in the rat was investigated clinically and biochemically. Galactose cataracts were induced in animals which had been injected with a single dose of sodium iodate and compared with those given a saline injection. The degeneration of retinal pigment epithelium was observed electron microscopically after sodium iodate injection. A slit lamp examination of the lens showed that, in animals injected with sodium iodate, galactose-associated lens alterations progressed faster, and mature cataract development was achieved earlier than in the saline-injected animals. Biochemical data which indicated a significantly higher concentration of Na+ and lower concentration of K+ in lenses of sodium iodate-injected animals confirmed the above clinical data. The level of galactitol was higher in lenses of sodium iodate-injected than those of saline-injected animals. Acceleration of the development of galactose cataract following sodium iodate injection is apparently due to the higher level of galactose entering the aqueous humor because of breakdown of blood-ocular barriers.
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PMID:Effect of sodium iodate injection on the development of galactose cataract in the rat. 318 99

We have demonstrated an increase in activity of arylsulfatase A and B during galactose induced cataract development in rats. Our recent investigation shows that acid phosphatase activity, which increases substantially during galactose cataract development in rats, could be contained to near normal level if Sorbinil, an aldose reductase inhibitor, was fed along with galactose to the rat. We have observed that the activity of other lysosomal enzymes, arylsulfatase A and/or B, also increases during galactose cataractogenesis. In the present report, we provide information with regards to the effect of Sorbinil on the activity of these enzymes during cataractogenesis. A modified Hopsu-Havu and Helminen method (1974) with p-nitrocatecholsulfate as substrate was used for localization of both arylsulfatase A and B; and the method of Hara et al. (1979) was utilized to obtain quantitative data on the level of arylsulfatase A and B activity. Ultrastructural cytochemistry shows that arylsulfatase activity in all lenses was primarily localized in epithelial cells in lysosomes with very little or no activity in cortical fibers. The number of arylsulfatase positive lysosomes and the activity level of these enzymes increased with the progression of cataract development. Galactose induced damage to lens morphology and increase in activity of arylsulfatase A and B was inhibited by inclusion of 50mg/Kg (diet) Sorbinil in the galactose containing cataractogenic diet. However, Sorbinil had no significant effect on the enzyme activity following the establishment of mature cataracts.
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PMID:Ultrastructural cytochemistry: effect of Sorbinil on arylsulfatases in cataractous lenses. 402 88

The authors performed galactose loading tests in children suffering from chronic diseases: recurrent bronchitis vomiting, diarrhoea, milk-intolerance, somatic and mental retardation, cramps. In 32 of the 92 examined cases galactose levels rose until pathological, pseudo- diabetic levels. Stillbirth, cataract, hyperbilirubinaemia, convulsions occurred among family members of 10 patients. Galactose-1-phosphat-uridyl-transferase levels were decreased only in 4 of the 17 patients examined. In the other cases some different pathway of galactose metabolism is suspected. Complete remission of symptoms was achieved with diet devoid of milk sugar (lactose) in 29 patients: one infant died and two others remained mentally retarded. According to the examinations presented minor deviations of galactose metabolism cause clinical symptoms more frequently in early life as it was supposed until now.
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PMID:[Galactose loading test in infants and small children suffering in recurrent bronchitis and other chronic illness (author's transl)]. 611 85

Three groups of 15 rats Wistar receive a well-balanced diet with 40 per cent of sucrose (T), lactose (P) or hydrolyzed lactose (PH) in the form of ultrafiltration permeate. After 160 days, no cataract is revealed in the T and P groups. In the PH group, 14 rats reached by cataracts in both eyes: it is slightly developed (PH 2), mildly developed (PH 3) or practically total (PH 4). The inositol disappearance, the high quantity of galactitol, the water and sodium increases are the factors observed before the lens opacification and are responsible for the cataract. Then, during the opacification, soluble proteins, potassium and hydratation of the lens decrease. Galactose 1-P is slowly formed before and during the lens opacification. The lens of the P group (lactose) differ from the control group (T) by the nature and the quantity of hexitols, only.
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PMID:[Reactions in the rats from prolonged consumption of lactose or hydrolyzed lactose. 3. Crystalline lens]. 716 Sep 73

Aldose reductase (AR) is implicated in the pathogenesis of the diabetic complications and osmotic cataract. AR has been identified as an osmoregulatory protein, at least in the renal medulla. An outstanding question relates to the response of AR gene expression to diet-induced galactosemia in extrarenal tissues. This paper shows that AR gene expression in different tissues is regulated by a complex multifactorial mechanism. Galactose feeding in the rat is associated with a complex and, on occasions, multiphasic pattern of changes in AR mRNA levels in kidney, testis, skeletal muscle, and brain. These changes are not in synchrony with the temporal sequence of changes in tissue galactitol, galactose, and myoinositol concentrations. Moreover, galactose feeding results in changes in tissue AR activities that are not related, temporally or quantitatively, to the alterations in tissue AR mRNA or galactitol levels. It is concluded that AR gene expression and tissue AR activities are regulated by mechanisms that are not purely dependent on nonspecific alterations in intracellular metabolite concentrations. This conclusion is supported by the finding that chronic xylose feeding, despite being associated with intracellular xylitol accumulation, does not result in alterations in AR mRNA levels, at least in the kidney.
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PMID:Effects of galactose feeding on aldose reductase gene expression. 832 80

An 8-year-old boy with galactose-1-phosphate uridyl transferase (GALT) deficiency presented with hypotonia, muscle hypotrophy, hepatomegaly, bilateral cataract and mild mental retardation. Two brothers showed a GALT activity consistent with a homozygotic condition and both parents were found to be heterozygotes for this defect. Histological and ultrastructural examination of muscle biopsy specimens showed several necrotic fibres. GALT activity was undetectable in skeletal muscle and muscle tissue cultures; myotubes converted galactose to CO2 at a lower rate than controls. Galactose-1-phosphate was increased in the patient's red cells and muscle tissue. GALT deficiency, not previously described in muscle, may be of pathogenic relevance in determining the myopathic features present in GALT deficiency syndrome.
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PMID:Clinical and biochemical evidence of skeletal muscle involvement in galactose-1-phosphate uridyl transferase deficiency. 832 30

Lactose consumption has been associated with a high incidence of cataract in northern Indian and southern Italian populations. Galactose absorbed after hydrolysis of lactose from milk in individuals with normal lactase activity is considered responsible. However, lactase-deficient subjects who often avoid drinking milk are able to digest lactose and absorb free galactose in fermented milk and yogurt. This study was conducted to evaluate the relationships between milk and yogurt consumption, galactose metabolism and cataract risk. Milk ingestion was dose-related with cataract risk in lactose digesters (particularly in diabetics) but not in lactose maldigesters. Conversely, yogurt intake had a protective dose-effect on cataract formation for the whole population. Maximal galactose concentrations after an oral galactose test increased exponentially with age. Red blood cell galactokinase activity was significantly lower in elderly subjects (> 60 y) than in young individuals (P < 0.05), and galactose-1-phosphate uridyl-transferase activity was significantly lower in institutionalized subjects and in home-living elderly with cataract than in healthy elderly subjects (P < 0.05). We conclude that the cataractogenic action of milk lactose is dependent on the disturbance of galactose metabolism in elderly subjects and that yogurt is not cataractogenic, although the mechanism of the protective effect of yogurt remains unknown.
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PMID:Disturbed galactose metabolism in elderly and diabetic humans is associated with cataract formation. 833 7


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