Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Metabolism of ascorbic acid is deranged in Diabetes Mellitus (DM). One important reason of this derangement is its increased turnover in the process of handling an increased load of free radicals. Anoxia, the triggering factor in the pathogenesis of diabetic retinopathy generates free radicals in anoxia-reperfusion sequence. Any process like argon laser photocoagulation that destroys the anoxic sites and improves oxygenation in retina might hinder the process of generation of free radicals and thus expected to preserve ascorbic acid. In this study plasma total ascorbic acid concentration in matched groups of (I) diabetics with retinopathy with no history of photocoagulation (II) diabetics with retinopathy treated by laser and (III) diabetics without microvascular pathology were measured by 2-4 dinitrophenyl hydrazine method. Plasma total ascorbate concentration was significantly higher in group-II (0.47 +/- 0.09 mg/dl; X +/- SD) in comparison to group-I (0.19 +/- 0.07 mg/dl P < 0.001). The concentration was not significant between group-II and group-III (0.49 +/- 0.06 mg/dl; P = 0.40). Other clinical and metabolic parameters were not significantly different in between the groups. This observation leads to speculation that photocoagulation saves ascorbic acid from excessive turnover in anoxic retina in the process of handling free radicals.
 ...
PMID:Comparison of plasma ascorbate status between diabetic retinopathy subjects with and without photo-coagulation therapy. 816 33

The present study was started to investigate the question of whether or not vitamin C administration may help control diabetes mellitus (DM) by stimulating the insulin mechanism of a DM patient. We were motivated to take up the above thesis by the anticipation that vitamin C, being detectable in abundance in endocrine cells, may play a cardinal role in the production of hormones. In the preliminary experiment, we investigated the relation between glucose, insulin and vitamin C in the plasma of a non-diabetic male volunteer in whom vitamin C was introduced intravenously either by injection or by infusion, and with or without concomitant administration of glucose. In the follow-up study of 3 DM patients, the effect of the vitamin C infusion therapy on DM was assessed by summing up multiple clinical information. Results obtained are as follows: 1) the drip infusion system was superior to the ordinary injection system for maintaining plasma concentration of vitamin C at a high level and for a long period. 2) The plasma concentration of insulin, when tested in the vitamin C infusion system, followed a bimodal curve--a finding to suggest that vitamin C may stimulate the insulin mechanism in 2 distinct ways. The early mode was glucose-dependent at its height, but the late mode was independent of glucose charge. 3) The praxis of vitamin C infusion produced clinical improvements in 3 DM patients. The therapeutic efficacy of the treatment varied from patient to patient. In all cases, control of DM was started by combined use of the vitamin C infusion treatment and the insulin injection treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Diabetes mellitus is controlled by vitamin C treatment. 819 73

The relationships of maternal prenatal dietary intakes and anthropometric measurements to pregnancy outcomes were investigated in a prospective observational study of urban African American women. The 322 subjects, a subset of the 744 women recruited for the study using purposive sampling, were all nulliparous, free of diabetes mellitus and abnormal hemoglobins, and delivered term, singleton infants. Sociodemographic data and monthly quantitative 24-hour food recalls were collected by trained interviewers. Maternal anthropometric measurements were obtained from the subjects' hospital records. Pregnancy outcome data were obtained by physical examinations of the newborn infants by the project pediatrician. With the exception of vitamin C, average maternal dietary intakes were within the ranges of intakes obtained in previous studies. Mean intakes of protein, vitamins A and C, thiamin, riboflavin, and niacin exceeded the 1989 RDA, while those of food energy, vitamin B-6, folate, calcium, iron, magnesium, and zinc were below the RDA. Underweight prior to pregnancy and low pregnancy weight gains were found among 12.9% and 44.4% of the subjects respectively. Dietary intakes were not significantly correlated with pregnancy outcomes. Maternal anthropometric measurements significantly correlated with pregnancy outcomes included delivery weight, pregnancy weight gain, weekly weight gain, prepregnancy weight, net weight gain, height, prepregnancy body mass index, and % ideal prepregnancy body weight (P < 0.05). Using the stepwise selection procedure in multiple regression analysis, delivery weight, % ideal prepregnancy body weight, and prepregnancy body mass index were selected as being predictive of infant birth weight. It was concluded that anthropometric measurements were better nutritional predictors of pregnancy outcome than dietary intake.
 ...
PMID:Dietary intakes, anthropometric measurements and pregnancy outcomes. 820 44

The relationships of selected lifestyle factors (cigarette smoking, consumption of alcoholic beverages, recreational drug use, and exercise during pregnancy), all self-reported, to pregnancy outcomes, dietary intake during pregnancy, and maternal anthropometric measurements, were investigated in a group of urban African American pregnant women. The 234 subjects were aged 16-35 years and were free of diabetes and abnormal hemoglobins. The lifestyle data were collected by trained interviewers during the subjects' prenatal clinic visits, and the dietary data by monthly, quantitative 24-hour food recalls conducted during these same visits. Maternal anthropometric measurements were obtained from the subjects' hospital records, and pregnancy outcome data during physical examinations of the newborn infants. Both cigarette smoking and drug use were associated with significantly lower mean birth weight, length, and head circumference, while exercise was associated with a significantly higher mean birth weight, and head circumference (P < 0.05). Drug use during pregnancy was associated with a significantly higher intake of vitamin C, and a significantly lower intake of iron; while women reporting drug use before pregnancy had significantly higher mean intakes of food energy, protein, total and saturated fat, and zinc. Prepregnancy weight, percent ideal prepregnancy body weight, prepregnancy body mass index, and delivery weight were significantly lower among those reporting drug use before pregnancy. Multiple regression analyses indicated that smoking explained a relatively small proportion of the variance in infant birth weight compared with delivery weight and percent of ideal prepregnancy body weight.
 ...
PMID:Selected lifestyle practices in urban African American women--relationships to pregnancy outcome, dietary intakes and anthropometric measurements. 820 47

Studies indicate that large doses of all-rac-alpha-tocopherol in people with diabetes or ascorbic acid in nondiabetic subjects reduces protein glycosylation. The mechanisms by which these nutrients influence glycosylation are poorly understood but may be related to their ability to function as antioxidants. We examined the relationship between glycosylated hemoglobin (GHb) and intake of vitamins E and C and beta-carotene in a population-based sample of middle-aged and older adults participating in the Beaver Dam Eye Study. In people with diabetes, no significant associations were observed between GHb and intake of vitamins E and C and beta-carotene. In people without diabetes, energy-adjusted vitamin C intake was negatively associated with GHb after age and sex were controlled for (dietary, P = 0.02; total, P = 0.04). No significant relationships between GHb and intake of vitamin E and beta-carotene were observed.
 ...
PMID:Glycosylated hemoglobin concentrations and vitamin E, vitamin C, and beta-carotene intake in diabetic and nondiabetic older adults. 823 54

The level of characteristic markers of protein oxidative modification (tryptophan oxidation and sulfhydryl group loss as well as carbonyl and bityrosine formation) and glycation (AGEP formation) have been measured in beta L crystallin purified from the lenses of control, diabetic, and ascorbate-supplemented diabetic animals. These markers were also determined following the application of an in vitro graded oxidative insult. Prior to the application of stress, diabetic lens crystallins, in comparison with control, exhibited a higher content of bityrosine and AGEPs, a lower level of nonoxidized tryptophan, and a loss of sulfhydryl groups. After exposure to the oxidative insult there was a stress-proportional increase of the parameters in all beta L crystallins, irrespective of their source. The effects were most pronounced in the diabetic, in which the already-elevated indicators of oxidative damage were further increased. Dietary supplementation of the diabetic group with ascorbate had a marked effect in preventing beta L crystallin modification in vivo, alleviating the loss of sulfhydryl groups and the oxidation of tryptophan, partially preventing the formation of AGEP and carbonyl groups, but not affecting the formation of bityrosine. Supplementation also inhibited the increase in susceptibility of diabetic beta L crystallin to in vitro oxidative stress, preventing sulfhydryl group loss as well as carbonyl and AGEP group formation. The results are discussed in relation to the proposal that diabetes renders lens crystallins more susceptible to oxidative stress and that this may be a causative factor in cataractogenesis. The possible role of ascorbate in the inhibition, or attenuation, of cataractogenesis is examined.
 ...
PMID:The effect of diabetes and dietary ascorbate supplementation on the oxidative modification of rat lens beta L crystallin. 826 Jan 97

Endothelium-dependent vasodilation is impaired in humans with diabetes mellitus. Inactivation of endothelium-derived nitric oxide by oxygen-derived free radicals contributes to abnormal vascular reactivity in experimental models of diabetes. To determine whether this observation is relevant to humans, we tested the hypothesis that the antioxidant, vitamin C, could improve endothelium-dependent vasodilation in forearm resistance vessels of patients with non-insulin-dependent diabetes mellitus. We studied 10 diabetic subjects and 10 age-matched, nondiabetic control subjects. Forearm blood flow was determined by venous occlusion plethysmography. Endothelium-dependent vasodilation was assessed by intraarterial infusion of methacholine (0.3-10 micrograms/min). Endothelium-independent vasodilation was measured by intraarterial infusion of nitroprusside (0.3-10 micrograms/min) and verapamil (10-300 micrograms/min). Forearm blood flow dose-response curves were determined for each drug before and during concomitant intraarterial administration of vitamin C (24 mg/min). In diabetic subjects, endothelium-dependent vasodilation to methacholine was augmented by simultaneous infusion of vitamin C (P = 0.002); in contrast, endothelium-independent vasodilation to nitroprusside and to verapamil were not affected by concomitant infusion of vitamin C (P = 0.9 and P = 0.4, respectively). In nondiabetic subjects, vitamin C administration did not alter endothelium-dependent vasodilation (P = 0.8). We conclude that endothelial dysfunction in forearm resistance vessels of patients with non-insulin-dependent diabetes mellitus can be improved by administration of the antioxidant, vitamin C. These findings support the hypothesis that nitric oxide inactivation by oxygen-derived free radicals contributes to abnormal vascular reactivity in diabetes.
 ...
PMID:Vitamin C improves endothelium-dependent vasodilation in patients with non-insulin-dependent diabetes mellitus. 855 Aug 38

The purpose of this review paper is to present relevant information for assessing the validity of our clinical investigation on the clinical usefulness of vitamin C infusion treatment tested in the control of autoimmune disease and allergy. Firstly, we describe the historical background of this study and then present the results of both experimental and clinical investigations as regards the therapeutic effect of vitamin C infusion treatment for the control of immune disorders including diabetes mellitus. Secondly, we discuss the interdisciplinary nature of our studies in the light of recent progress in clinical vitaminology, endocrinology and immunology. Thirdly, we suggest the possibility that the use of our vitamin C infusion treatment may be beneficial in the clinical management of AIDS, of which the immunological background data are in favor of the participation of an autoimmune mechanism in the genesis of this disease. Finally, we stress the importance of paradigm change in the achievement of a breakthrough in natural science.
 ...
PMID:Vitamin C and the genesis of autoimmune disease and allergy (review). 856 89

Increased generation of reactive oxygen species, coupled with impaired endogenous scavenging mechanisms, plays a prominent role in the aetiology of neurovascular abnormalities in experimental diabetes mellitus. We examined the efficacy of the natural anti-oxidants vitamins C, E and beta-carotene in preventing nerve conduction and nutritive blood flow deficits in streptozotocin-diabetic rats. One month of diabetes caused a 19.1% reduction in sciatic motor conduction velocity (p < 0.001). This was approximately prevented 80-90% by high-dose (1000 mg.kg-1.day-1) vitamin E and beta-carotene treatments (p < 0.001). Vitamin C had lesser effects; the maximum protection found for motor conduction velocity was 36% using a dose of 150 mg.kg-1.day-1 (p < 0.001). High dose (500 mg.kg-1.day-1 (p < 0.001). High dose (500 mg.kg-1.day-1) vitamin C had a lesser effect on conduction than intermediate doses. Joint vitamin C and lower dose (500 mg.kg-1.day-1) vitamin E treatment had a predominantly additive preventive effect against nerve dysfunction. Resistance to hypoxic conduction failure for sciatic nerve in vitro was markedly increased by diabetes and this remained relatively unaffected by treatment. Sciatic nutritive endoneurial blood flow, measured using microelectrode polarography and hydrogen clearance, was reduced 46.1% by 1 month of diabetes (p < 0.001). This was prevented to the extent of 87%, 36% and 98% by vitamins E, C and beta-carotene, respectively (p < 0.01). These data emphasize the role of oxidative stress in the development of early neurovascular changes in experimental diabetes and show that naturally available scavengers have a neuroprotective action.
 ...
PMID:Effects of natural free radical scavengers on peripheral nerve and neurovascular function in diabetic rats. 858 37

Plasma concentrations of the antioxidant vitamin ascorbic acid were measured by high-performance liquid chromatography in critically ill patients in whom the excessive generation of reactive oxygen species could compromise antioxidant defense mechanisms. Median concentrations of both total vitamin C (ascorbic acid and dehydroascorbic acid) and ascorbic acid in these patients were < 25% (P < 0.001) of the values found in healthy control subjects and in subjects in two other disease groups (diabetes, gastritis) in which reactive oxygen species are reported to be increased. The low values could not be explained by age, sex, intake, or treatment differences, but were associated with the severity of the illness and were not prevented by the use of parenteral nutrition containing ascorbic acid. In addition, the vitamin was less stable in blood samples taken from critically ill patients than in similar samples from subjects in the other groups. The findings indicate that antioxidant defenses could be considerably compromised in these very sick patients. If this reduces the patient's capacity to scavenge reactive species, then the potential of these species to damage DNA and lipid membranes could be increased and compromise recovery.
 ...
PMID:Total vitamin C, ascorbic acid, and dehydroascorbic acid concentrations in plasma of critically ill patients. 861 61


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>