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

The effects of vitamin E and D-myo-inositol 1,2,6-trisphosphate (PP-56) were investigated in long-term studies in streptozocin-induced diabetic rats fed a purified diet with 33% lipids and a polyunsaturated-to -saturated fatty acid ratio of 1. A supplement of vitamin E decreased plasma triglycerides, platelet lipid biosynthesis, some of the delta 6- and delta 5-desaturase abnormalities, and urine ketone bodies but did not affect the response of platelets to aggregation. PP-56 completely normalized the platelet reactivity to ADP and thrombin. This was accompanied by normalization of platelet lipid biosynthesis and diabetes-induced abnormalities in delta 6- and delta 5-desaturases. PP-56 treatment also reduced the mortality rate and to a certain extent urinary ketone bodies. The protective effect of PP-56 on platelet aggregation and mortality rate were dose related. PP-56, a molecule derived from phytic acid, seems to exert potent protective effects on some of the manifestations associated with diabetes in rats.
Diabetes 1991 Feb
PMID:Effects of PP-56 and vitamin E on platelet hyperaggregability, fatty acid abnormalities, and clinical manifestations in streptozocin-induced diabetic rats. 182 73

Although any cardiovascular complications of combined oral contraceptive (OC) use have dramatically increased in the past decade, both as a result of lower dosages (under 50 mcg) of estrogen in newer OCs and the recommendation that this method be used only by nonsmokers under 35 years of age, there remains a need to deepen understanding of the mechanisms involved. The increased levels of estrogen in OCs, associated with free radical generation, lead to a disruption in oxidative status. Further deterioration occurs when other risk factors (smoking, diabetes, or nutritional insufficiency) that also induce the production of free radicals and promote lipid peroxidation are present. The increase in plasma lipid peroxides appears to be responsible for the hyperaggregability and imbalance in clotting factors associated with the OC-induces thrombotic state. This hyperaggregability is modulated in OC users by the intake of polyunsaturated fan and antioxidants. Key to the avoidance of thrombotic events in OC users is the screening out of potential acceptors with risk factors such as smoking that act synergistically with OCs. Determination of platelet reactivity should be considered in questionable cases. Since vitamin E has been shown to improve platelet reactivity and oxidative status in OC users, its addition directly to the pill should be considered as a preventive measure. Now that the link between thrombogenic mechanisms and lipid peroxidation has been established, research should be undertaken to separate the estrogenic from the free radical-inducing properties of OCs.
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PMID:Oxidative status and oral contraceptive. Its relevance to platelet abnormalities and cardiovascular risk. 185 73

Vitamin E deficiency in erythrocytes causes decreased cell survival, hypercoagulability, and increased adhesiveness to the endothelium. Similar abnormalities are found in erythrocytes of the diabetic population. This study examines the effect of diabetes on vitamin E and lipofuscin products (aging pigments) in erythrocytes of streptozocin-induced diabetic rats. Controls were injected with buffer alone, and a subgroup consisting of insulin-treated diabetic rats were injected daily with insulin for 2 mo. Mean +/- SD vitamin E levels were 23.2 +/- 4.9, 19.4 +/- 3.2, and 25.9 +/- 2.5 nmol/mumol phospholipid. Lipid fluorescence values (relative values/phospholipid) were 11.1 +/- 1.9, 14.1 +/- 2.6, and 11.9 +/- 1.8 (excitation/emission 360/440 nm) in control, diabetic, and insulin-treated diabetic rats, respectively. Differences in vitamin E and lipofuscin products were significant between all control and diabetic groups and diabetic and insulin-treated diabetic groups. Reduction in vitamin E and increases in lipofuscin products in diabetic rats were significant even when values were expressed per micromole Hb or per 100 ml erythrocytes. This study demonstrates that hyperglycemia significantly reduces vitamin E and increases lipofuscin products in erythrocytes of diabetic rats. These effects were prevented with insulin treatment.
Diabetes 1991 Oct
PMID:Reduced vitamin E and increased lipofuscin products in erythrocytes of diabetic rats. 193 87

Ascorbic acid (AA), dehydroascorbic acid (DHAA), and vitamin E were measured in tissues and plasma of 30 control and 30 spontaneously diabetic BioBreeding rats (BBdp) during development and before the onset of diabetes. At weaning, rats were fed an AIN-76 semisynthetic diet for 30, 64, or 113 days, after which plasma and tissues from 10 rats of each group were collected and analysed for AA, DHAA, and vitamin E. AA and DHAA levels were significantly increased in plasma and spleen of the diabetes-prone rats compared with those of the control group at 30 and 64 days, but the difference disappeared by 113 days. No differences were observed in liver, adrenals, thymus, and pancreas at any of the time periods. However, lower levels of vitamin E were observed in adrenal gland, thymus, and pancreas of the diabetes-prone rats. It is concluded that BBdp rats have an altered metabolism of AA, DHAA, and vitamin E, before the onset of diabetes. These changes could be due to genetic and physiological factors operating during development of this rat strain.
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PMID:Vitamin C and vitamin E status in the spontaneously diabetic BB rat before the onset of diabetes. 198 74

The possible value of radical scavengers in the prevention of beta cell destruction was studied in two animal models of type I diabetes. Eight compounds were tested alone or in combinations. In the low-dose streptozotocin model treatment started 24 hr after the last injection of the beta cell toxin, in the BB rat daily administration was started at 50 days of age (i.e., 20-70 days before diabetes onset). No effect was seen in the low-dose streptozotocin model for 3-aminobenzamide, N-acetyl-DL-homocysteine thiolactone, ebselen, and butylated hydroxyanisole whereas partial suppression of hyperglycaemia was seen in mice receiving cysteamine. In BB rats diabetes development was delayed and partially suppressed by administration of ebselen plus vitamin E plus MaxEPA (fish lipid concentrate), but not when ebselen was replaced by nicotinamide. We conclude that the disease process is not readily modifiable by treatment with exogenous radical scavengers.
Diabetes Res 1990 Feb
PMID:Effects of radical scavengers on the development of experimental diabetes. 209 72

A decrease in the vitamin E content of human diabetic platelets is closely associated with the accelerated platelet aggregation and platelet prostaglandin metabolism seen in patients with diabetes mellitus. We investigated the effect of vitamin E supplementation on these abnormalities of physiological function and prostaglandin metabolism in 14 non-insulin dependent diabetics with proliferative retinopathy. ADP-induced platelet aggregation was inhibited in vitro by the addition of vitamin E in a dose-dependent manner. However, in lower concentrations considered to be physiological doses in vivo, significantly greater inhibition was observed in diabetic platelets than in the control platelets. Next, alpha-tocopheryl nicotinate was administered to diabetics at a daily dose of 600 mg. The platelet vitamin E content was restored to control levels in 13 of the 14 patients after 2-4 weeks of daily administration. The ADP-induced platelet aggregation rate, platelet thromboxane B2 (TXB2, a stable metabolite of TXA2, a vasoconstrictor production, and plasma TXB2 level were low in all 14 diabetics. In contrast, plasma 6-keto-PGF 1 alpha (a stable metabolite of PGI2, a vasodilator) was significantly increased and therefore the 6-keto-PGF 1 alpha/TXB2 ratio in plasma was restored to within normal limits. These results indicate that vitamin E may improve platelet function and prostaglandin metabolism in diabetes mellitus and may be able to provide further beneficial effects in relation to the development of diabetic vascular complications.
Diabetes Res 1990 May
PMID:Effects of vitamin E administration on platelet function in diabetes mellitus. 213 64

Age-related cataract is a condition characterized by multiple mechanisms and multiple risk factors. The mechanisms that bring about a loss in transparency include oxidation, osmotic stress, and chemical adduct formation. Risk factors for cataract include diabetes, radiation (ultraviolet B, x-ray), certain pharmaceutical substances, certain nutritional states, and possibly acute episodes of dehydration. Interaction occurs between and among mechanistic factors and risk factors. Thus nutrition must be considered as one part of a tapestry of intertwined events and responses. Certain experimental models for nutritional cataract have been useful for study of the cataractogenic process but are probably not important factors in the human disease. Little current evidence supports significant roles in human senile cataract for imbalances of tryptophan or other amino acids, deficiencies of calcium or selenium, or excessive intake of selenium. Overconsumption of galactose is likely to be hazardous only in subjects with genetic inability to metabolize this sugar. Vitamins with antioxidant potential (riboflavin, vitamin E, vitamin C, carotenoids) deserve further research scrutiny to ascertain their significance in cataract etiology. Excessive caloric intake needs to receive added emphasis as a factor contributing to cataract. Diabetes increases the likelihood of cataract three- to four-fold. Obesity, defined as more than 20% overweight, is considered a major risk factor for non-insulin-dependent, or type II, diabetes (69, 73). Weight control can be recommended as a prudent, safe, economic, and effective means of lowering risk probability for diabetes and the associated complication of cataract.
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PMID:Nutritional factors in cataract. 220 Apr 64

Thirteen patients with adult-onset vitamin E deficiency due to fat malabsorption were investigated clinically and electrophysiologically. These patients had slightly or moderately decreased serum vitamin E (1.7-4.8 micrograms/ml, normal less than 6.0) or vitamin E/cholesterol ratio (0.21-0.31 mg/g, normal less than 0.35). Only one patient had typical neurological manifestations of vitamin E deficiency, which improved with supplementary vitamin E. The pathological findings in this patient were also compatible with vitamin E deficiency. This patient had poorly controlled diabetes mellitus due to advanced chronic pancreatitis. Reviewing previously reported cases of vitamin E deficiency with diabetes mellitus in chronic pancreatitis, the duration of deficiency until the onset of symptoms was shorter than in those cases without complications. Although adult patients with early, slight deficiency of vitamin E are generally asymptomatic, patients with diabetes mellitus tend to have early neurological symptoms. The vitamin E tolerance test should be used, because even in some patients with vitamin E deficiency due to malabsorption, the deficiency can be overcome by large oral doses of vitamin E.
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PMID:Vitamin E deficiency in acquired fat malabsorption. 235 33

Thirty-nine patients with noninsulin-dependent diabetes on oral drug treatment were randomly allocated to either guar gum or placebo treatments for 3 mo. After 3 mo the placebo group was switched to guar gum treatment and both groups were followed for 10 mo (open trial). No significant difference occurred in the fasting blood glucose or glycosylated hemoglobin A1 levels between the two groups at 3 mo. Serum total cholesterol level decreased in the guar gum group from 6.55 +/- 1.45 to 5.69 +/- 1.2 mmol/L (p less than 0.001) but no changes were observed in the placebo group (6.55 +/- 1.2 vs 6.26 +/- 1.4 mmol/L, NS) during 3 mo. At the end of the open trial (n = 33), serum cholesterol was still approximately 7% lower than before guar gum treatment. No consistent changes occurred in serum HDL-cholesterol or triglycerides. Serum vitamin A level was slightly lowered and plasma zinc level elevated during the open trial. Serum vitamin E level was decreased only in the group switched to guar gum at 3 mo.
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PMID:Metabolic and nutritional effects of long-term use of guar gum in the treatment of noninsulin-dependent diabetes of poor metabolic control. 253 3

Increased lipid peroxidation products were detected in a lipoprotein fraction containing very low density lipoprotein (VLDL) and low density lipoprotein (LDL) obtained from rats made diabetic by streptozotocin injection. The enhanced oxidation in the diabetic VLDL plus LDL fraction correlated with the in vitro toxicity of this lipoprotein fraction to proliferating fibroblasts. In contrast, high density lipoprotein (HDL) was not cytotoxic. That the increased oxidation and development of cytotoxic activity in the diabetic VLDL + LDL was related to the diabetes was shown by the fact that insulin treatment of diabetic animals inhibited both oxidation and cytotoxicity of VLDL + LDL. In contrast, treatment of diabetic rats with the antioxidants vitamin E or probucol after diabetes was established also inhibited both the in vivo oxidation and in vitro cytotoxicity of diabetic VLDL + LDL, but without altering hyperglycemia. Vitamin E or probucol treatment thus allowed separation of the oxidation process from the hyperglycemia occurring in experimental diabetes. The mechanisms by which diabetes in humans or experimental animals leads to the various manifestations of tissue damage are unknown; however, these studies demonstrate for the first time that a relationship exists between the in vivo oxidation of lipoproteins in diabetes and the potential for tissue damage as monitored by in vitro cytotoxicity. Furthermore, these results suggest that the mechanism for certain aspects of tissue damage accompanying experimental diabetes may be mediated by lipid peroxidation products.
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PMID:Antioxidant treatment of diabetic rats inhibits lipoprotein oxidation and cytotoxicity. 262 11


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