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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There is increasing evidence that islet beta cells may be susceptible to redox insult, and that this susceptibility may contribute to the pathogenesis of experimental models of diabetes mellitus. We investigated the effect of vitamin E deficiency, selenium deficiency, and combined deficiency on islet function and free radical scavenging systems. The tissue levels of glutathione peroxidase, catalase, and immunoreactive superoxide dismutases were measured in four groups of rats (i.e., controls and those with vitamin E, selenium, and combined deficiency). Glucose tolerance tests were performed for each animal before sacrifice. Superoxide dismutase concentrations in liver, heart, and skeletal muscle were within 20% of the control levels in all groups. However, the manganosuperoxide dismutase concentrations in islets were significantly lower than control levels in response to vitamin E, selenium, and combined deficiency. Combined deficiency appeared to have an additive effect. In contrast, cuprozinc superoxide dismutase concentration in islets was higher in the deficient groups than in controls. Insulin secretory reserve was decreased in each of the three deficient groups. This decrease was reflected as glucose intolerance only in the group with combined deficiency. Glutathione peroxidase activity was markedly decreased in selenium-deficient animals in all tissues studied. Catalase activity did not change significantly among groups in any tissue studied. Islets had the lowest glutathione peroxidase and cuprozinc and total superoxide dismutase levels among tissues studied.
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PMID:Effect of vitamin E deficiency and selenium deficiency on insulin secretory reserve and free radical scavenging systems in islets: decrease of islet manganosuperoxide dismutase. 351 3

Weanling diabetes-prone BB rats were fed AIN-76 diets containing high (HE, 1 g/kg diet), basal (NE, 0.2 g/kg) or low (LE, trace) vitamin E and were killed at 21, 42 or 60 days of age. Plasma and tissues (adrenals, pancreas, spleen, thymus, liver, brown and white adipose tissue, muscle and testes) were analysed for vitamin E. Vitamin E levels reflected the level in the diet and no diabetic animals were detected at these times. In a second experiment, a total of 90 diabetes-prone BB rats were kept on diets LE and HE for 6 months or until they became diabetic. 11/45 on LE and 5/45 on HE became diabetic. Again, plasma and tissue levels of vitamin E reflected the levels in the diet with the exception of the thymus of diabetic rats fed the high vitamin E diet. Thymus vitamin E levels (microgram/g tissue) were 1.8 and 1.2 in LE-fed diabetics and asymptomatic rats, respectively; and 22.7 and 49.5 in HE-fed diabetics and asymptomatic rats, respectively. The last 2 values were significantly different (p less than 0.005). There were no other differences in plasma or tissue levels of vitamin E in these groups of animals. These findings suggest that high dietary vitamin E may decrease the incidence of diabetes in animals which are able to accumulate sufficient amounts of the vitamin in the thymus. Since the thymus plays a key role in the maturation of T cell populations, which appear to be altered in this disease, it seems possible that the protective effect may be exerted at this level.
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PMID:Effect of dietary vitamin E on the vitamin E status in the BB rat during development and after the onset of diabetes. 352 49

Blood plasma of patients with arteriosclerosis obliterans and diabetes showed a higher antioxidant potency as compared with plasma of healthy volunteers. Serum copper level in those patients was also elevated, but on the contrary to healthy subjects no correlation between serum copper level and plasma antioxidant potency was found. Similar changes were observed in rabbits fed four weeks with atherogenic diet. Administration of vitamin E increased plasma antioxidant potency, however, only in the patients suffering from arteriosclerosis obliterans with high regime of dosage of vitamin E (3 X 200 mg daily p.o.). N-ethylmaldimide-stimulated (malondialdehyde (MDA)) generation by washed platelets was suppressed by addition of homologous plasma to washed platelet preparation. Preincubation of rat aortic tissue with plasma from healthy volunteers resulted in an increase in PGI2-biosynthesis b 75%. We were not able to demonstrate the antioxidant activity of aortic endothelial cell homogenates. We conclude that antioxidant properties of plasma may play an important role in protection of serum lipids against autooxidation. Antioxidant ability of plasma is not exclusively correlated with plasma copper or ceruloplasmin level.
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PMID:Plasma antioxidant potency and serum copper levels in atherosclerosis. 390 Sep 61

New aspects of vitamin E metabolism have demonstrated new indications for its use in pediatrics. With respect to the retrolental fibroplasia of prematures under intensive care it can be stated that vitamin E does not necessarily prevent this complication but surely can decrease its severity. For the intensive care of newborns it is of importance that vitamin E is apparently able to decrease the frequency of intraventricular hemorrhage. The effect of vitamin E on the metabolism of prostaglandins opens new insights in the understanding of thrombocyte aggregation and atherogenesis. There may be a possible indication for the substitution of vitamin E in patients with diabetes mellitus type I.
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PMID:[Recent aspects of vitamin E in pediatrics]. 390 55

Vitamin E content and biosynthesis of 12-hydroxyeicosatetraenoic acid (12-HETE) have been measured in platelets from type I diabetic subjects and age- and sex-matched, nondiabetic control subjects. Platelets from diabetic subjects synthesized significantly greater quantities of 12-HETE than did platelets from control subjects when 12-HETE synthesis was induced by thrombin or collagen, either in the presence or absence of indomethacin. Platelet conversion of exogenously added arachidonic acid (AA) to 12-HETE was not significantly different between the diabetic and control groups in the absence of indomethacin, although a small but significant increase in the conversion of AA to 12-HETE was present in the diabetic group platelets when indomethacin was added to the reaction. Vitamin E content was significantly reduced in platelets from the diabetic subjects, when compared with platelets from the control subjects, although plasma vitamin E levels were not significantly different between the two groups. Thrombin- and collagen-induced platelet 12-HETE synthesis demonstrated a significant negative linear correlation with platelet vitamin E content when measurements from both diabetic and control groups were combined. The above data suggest a relationship between low vitamin E content and increased 12-HETE synthesis in platelets from type I diabetic subjects.
Diabetes 1985 Jun
PMID:Production of 12-hydroxyeicosatetraenoic acid and vitamin E status in platelets from type I human diabetic subjects. 392 90

The composition and nutritional adequacy of subject-selected high carbohydrate, low fat diets were investigated in six women with insulin-dependent diabetes mellitus. Subjects were randomly assigned to begin either the experimental diet with 65% carbohydrate, 20% fat, and 15% protein for 6 wk, or a control diet with 45% carbohydrate, 40% fat, and 15% protein for 4 wk. All subjects completed both dietary periods in a cross-over experimental design. Subjects were allowed free selection in their choice of carbohydrate-rich foods. The resulting selections produced diets with 51% simple and 49% complex carbohydrates and 50 g of dietary fiber during the experimental diet. Similar proportions were also selected during the control diet. Blood chemistries revealed no significant changes in thiamin, riboflavin, vitamin B6, pyridoxal 5'-phosphate, ascorbate, vitamin E, calcium, selenium, or zinc concentrations between the two dietary periods. With the exception of vitamin B6, all vitamin and mineral values were within normal respective ranges. Vitamin B6 status, as assessed by pyridoxal 5'-phosphate, were below or just above the levels of marginal deficiency (2.2 nmol/100 ml) in four of the six individuals, but the lower level observed occurred independent of the dietary treatments. The present study demonstrates that subject-selected high carbohydrate, low fat diets were much lower in complex carbohydrates and fiber than diets previously tested. In addition, the concentration of several nutrients did not appear to be adversely affected by these diets.
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PMID:The composition and nutritional adequacy of subject-selected high carbohydrate, low fat diets in insulin-dependent diabetes mellitus. 634 10

Diabetic subjects tend to develop microvascular complications believed to be due to platelet hyperaggregability. This increased platelet sensitivity is though to be the result of an imbalance of PGI2 and TXA2 production in diabetes. This study sought to determine whether megavitamin E supplementation could restore PGI2/TXA2 balance in streptozotocin-diabetic rats. Endogenous release of PGI2 by isolated aorta, determined via radioimmunoassay of its stable metabolite, 6-keto-PGF1 alpha, was significantly greater (P less than 0.05) in rats receiving 100x the normal vitamin E requirement than in untreated diabetic rats. PGI2 synthesis was negatively correlated with plasma glucose levels (r = -0.87, P less than 0.05) in non-fasted rats at sacrifice. Vitamin E supplementation, at both the 10x and the 100x level, significantly depressed (P less than 0.05) thrombin-stimulated synthesis of TXA2 in washed platelet. PGI2 and TXA2 production were expressed as a ratio. Megavitamin E therapy appears to increase this ratio over that seen in the diabetic animal. The data suggest that vitamin E, at high levels, exerts an ameliorating influence of the PGI2/TXA2 imbalance of diabetes.
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PMID:Differential effects of megavitamin E on prostacyclin and thromboxane synthesis in streptozotocin-induced diabetic rats. 635 Jan 38

Increased plasma and tissue levels of vitamin E were found in spontaneously diabetic BB rats (D) as well as asymptomatic/diabetes-prone BB rats (AD) in comparison to levels in non-diabetic control rats (ND). Treatment of D rats with insulin for 30 days returned plasma and tissue values of vitamin E to control levels. The changes reported here could not be explained solely on the basis of variations in total lipid content of plasma. These data suggest the metabolism of vitamin E is altered in asymptomatic and spontaneously diabetic BB rats and this alteration returns to control values following insulin treatment. Furthermore, it might be speculated that these data indicate a relationship between vitamin E and insulin.
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PMID:Increased plasma and tissue levels of vitamin E in the spontaneously diabetic BB rat. 637 93

Spontaneous platelet aggregation (SPA), a phenomenon observed in vitro, was noted in 29 of 74 (39%) children and adolescents with insulin-dependent diabetes. Its occurrence was independent of age of onset, duration of diabetes, HbAI levels or presence of background retinopathy but varied between normal and abnormal in given individuals tested repeatedly over some time. Plasma beta-thromboglobulin, the platelet protein specific for Phase II of the release reaction, was elevated in the diabetic subjects but was independent of the occurrence of SPA. SPA in the diabetic children and adolescents, in contrast to SPA in other conditions, was not suppressed by either acute or chronic administration of aspirin adequate to suppress ADP induced second wave aggregation. SPA was uniformly suppressed by addition to the in vitro system of EDTA, adenosine, antisera to human fibrinogen or vitamin E. The data suggest that SPA is ADP induced and reflects either abnormal platelet membrane permeability to the nucleotide or its abnormal release, or abnormal platelet sensitivity to normal plasma levels of ADP.
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PMID:Some characteristics of spontaneous platelet aggregation in young insulin-dependent diabetic subjects. 645 81

There are two families of essential fatty acids, the linoleic and linolenic. Linoleic acid (C18:2n-6), found mainly in vegetable seed oils, is desaturated and elongated in the body, forming arachidonic acid (C20:4n-6). Linolenic acid (C18:3n-3), the main dietary source of which is leaves, is desaturated and elongated, forming two fatty acids that are prevalent in fish oils: timnodonic (C20:5n-3) and clupanodonic (C22:6n-3). EFA are very easily peroxidized in air, but vitamin E protects against this. There are three functions of EFA. The most important is as part of phospholipids in all animal cellular membranes: in deficiency of EFA faulty membranes are formed. A second is in the transport and oxidation of cholesterol: EFA tend to lower plasma cholesterol. A third function is as precursors of prostanoids which are only formed from EFA. Deficiency of EFA in experimental animals causes lesions mainly attributable to faulty cellular membranes: sudden failure of growth, lesions of skin and kidney and connective tissue, erythrocyte fragility, impaired fertility, uncoupling of oxidation and phosphorylation. In man pure deficiency of EFA has been studied particularly in persons fed intravenously. A relative deficiency (that is, a low ratio in the body of EFA to long-chain saturated fatty acids and isomers of EFA) is common on Western diets and plays an important part in the causation of atherosclerosis, coronary thrombosis, multiple sclerosis, the triopathy of diabetes mellitus, hypertension and certain forms of malignant disease. Various factors affect the dietary requirement of EFA.
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PMID:Essential fatty acids in perspective. 646 3


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