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Role of the non-enzymatic glycosylation of protein in the formation of human cataracts
We have measured the free epsilon amino groups in soluble and insoluble proteins of clear human lenses and diabetic and non-diabetic senile cataractous lenses. The free epsilon amino groups content of soluble and insoluble proteins was significantly lower in diabetic cataracts than in clear lenses and non diabetic senile cataracts. Our results seem to demonstrate that non-enzymatic glycosylation of lens protein could play a role in the pathogenesis of cataract in diabetes
Genetic risk factors in myocardial infarction at young age. Minerva Cardioangiol. 2004 Aug;52(4):287-312
Lipid peroxidation and cataract formation in experimental diabetes
To investigate the role of lipid peroxidation in diabetic cataractogenesis, malondialdehyde, a breakdown product of lipid peroxidation, was measured in lenses with incipient opacities and in retinas from diabetic rats and in clear lenses and in retinas from normal rats. The malondialdehyde mean values obtained in the transparent and cataractous lenses showed non-significant differences, while non-diabetic rat retinas had a significantly lower mean level of malondialdehyde compared with diabetic rat retinas (p less than 0.01). This indicates that, in streptozotocin-induced diabetic rats, lipid peroxidation is apparently not involved in the development of cataract, but it is quite probably involved in retinal damage. The retina, richer in polyunsaturated fatty acids than other ocular structures, is the elective site of lipid peroxidation and from this membrane peroxidation products might probably diffuse and damage other ocular tissues
Systemic human diseases as oxidative risk factors in cataractogenesis. I. Diabetes
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 damages could play a role in the pathogenesis of cataract in diabetes
Two genetic loci participate in the regulation by iron of the gene for the human transferrin receptor.
Possible role of altered levels of plasma docosahexaenoic acid in the pathogenesis of retinitis pigmentosa. Preliminary results
Plasma samples obtained from Retinitis Pigmentosa (R.P.) patients and controls were assayed for docosahexaenoic acid (DXA), the major fatty acid in photoreceptor cells, in order to evaluate the possibility that abnormalities in PUFA metabolism could be involved in R.P. pathogenesis. Our preliminary results show levels of plasma DXA in dominantly inherited R.P. lower than in the recessive forms and controls
Hydrogen peroxide in the aqueous humor and cataract formation in human diabetes
Hydrogen peroxide in the aqueous humor was measured in cataractous eyes from normal subjects and in cataractous eyes from diabetic subjects. The level of H2O2 in the aqueous humor was significantly higher in diabetes than in the idiopathic forms. It is likely that in the eye, impaired enzymic defenses lead to the accumulation of reactive species of O2, such as H2O2, which induces lipid peroxidation. This mechanism may be involved, as a direct consequence of retinal damage, in the pathogenesis of cataract in diabetes
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