thiobarbituric-acid and Diabetes-Mellitus--Type-1

Placebo for 3 months, followed by 30 mg/day zinc gluconate in identical capsules.. Diabetic out patients clinic at the University Hospital, Grenoble.. Diabetic patients cared for type I diabetes mellitus. 22 patients began the study, 4 dropped out. 10 patients suffered of an early retinopathy, 8 patients had no retinopathy.. In this order: T0 biological measurements, 3 months placebo treatment, T1 biological measurements, 3 months zinc gluconate treatment, T2 biological measurements. Plasma Zn, Cu, Se, thiobarbituric acid reactants and antioxidant enzymes were measured [plasma and red glutathione peroxidase (Se-GPx), red cell superoxide dismutase (Cu-Zn-SOD)].. Lower plasma zinc level in the two groups. An increase in zinc level was observed and was more important in diabetic patients with no retinopathy (P = 0.05). The thiobarbituric acid reactants were above the reference values in all the patients, and were decreased at T2 (P < 0.05). Increase of GPx activity after zinc supplementation in patients with retinopathy.. Zinc deficiency in insulin-dependent diabetic patients is corrected by a zinc supplementation. Moreover this supplementation decreases lipid peroxidation. The effects of zinc are different in diabetic patients with or without retinopathy. The increase in Se-GPx activity observed in patients with retinopathy could be linked to the protective effect of zinc on the protein itself.

Topics: Adult; Copper; Diabetes Mellitus, Type 1; Diabetic Retinopathy; Female; Gluconates; Glutathione Peroxidase; Humans; Lipid Peroxidation; Male; Selenium; Superoxide Dismutase; Thiobarbiturates; Zinc

Diabetes mellitus type 1 provokes the development of the oxidative stress, accompanied by the increased level of TBA-active products, activation of NO-synthases and increased production of nitric oxide. Activation of glutathione reductase, decrease of the glutathione peroxidase and superoxide dismutases activity was observed. This shows a specific disturbance in the functioning of the antioxidant defense system and the augmentation in the concentration of one of the major first line reacting cytokin (IL-1beta).

Topics: Adult; Antioxidants; Diabetes Mellitus, Type 1; Female; Glutathione Peroxidase; Glutathione Reductase; Humans; Interleukin-1beta; Male; Nitric Oxide; Nitric Oxide Synthase Type II; Oxidative Stress; Superoxide Dismutase; Thiobarbiturates

In vivo metabolism of salicylic acid produces two main hydroxylated derivatives (2,5- and 2,3-dihydroxybenzoic acid). The former can be produced by enzymatic pathways through the cytochrome P-450 system, while the latter is reported to be solely formed by direct hydroxyl radical attack. Therefore, measurement of 2,3-dihydroxybenzoate, following oral administration of salicylate in its acetylated form (aspirin), has been proposed for assessment of oxidative stress. In this article we report plasma levels of 2,3- and 2,5-dihydroxybenzoates following the administration of 1 g aspirin and plasma levels of thiobarbituric acid-reactive material (TBARM) in well-controlled diabetic patients and in healthy subjects. 2,3-Dihydroxybenzoate levels were significantly higher (23%) in diabetic patients than in controls (63.4 +/- 20.1 versus 49.0 +/- 6.8 nM; p < .05). On the other hand, TBARM values were not significantly different between groups. These results suggest that the method is useful to reveal in vivo oxidative stress independently from the peroxidation of lipids, and they support the hypothesis that oxygen radicals are involved in the pathogenesis of chronic complications of diabetes.

Topics: Adult; Aspirin; Diabetes Mellitus, Type 1; Female; Gentisates; Humans; Hydroxybenzoates; Hydroxylation; Male; Oxidation-Reduction; Reactive Oxygen Species; Salicylates; Thiobarbiturates

Glycosylated haemoglobin was measured in venous blood samples and in blood collected in 'Unistep' bottles by isoelectric focusing (IEF), as the reference method, and by electroendosmosis (EEO), the thiobarbituric acid method (TBA), ion-exchange chromatography (IEC) and affinity chromatography (AC). Isoelectric focusing, electroendosmosis and thiobarbituric acid gave similar results. Affinity chromatography gave lower results than isoelectric focusing for normal values but similar results for diabetics. Ion-exchange chromatography gave 24% lower results than isoelectric focusing across the range. Using Unistep collected blood samples and comparing multiple samples from the same patient, electroendosmosis gave the best results (coefficient of variation 4%) and thiobarbituric acid gave slightly less good precision that other methods. Re-use of affinity chromatography columns gave less good precision. Collection of blood samples into a Unistep bottle gave similar results to venous sample results. Storage of venous capillary blood samples in Unistep bottles over 1 week at 21 degrees C gave similar results to immediate assay. Electroendosmosis of blood samples in Unistep bottles gave stable results over 2 weeks. Home collection by a patient of a capillary blood sample into a Unistep bottle allows glycosylated haemoglobin results to be available when seen in the clinic.

Topics: Capillaries; Chromatography, Affinity; Chromatography, Ion Exchange; Diabetes Mellitus, Type 1; Evaluation Studies as Topic; Glycated Hemoglobin; Humans; Isoelectric Focusing; Osmosis; Temperature; Thiobarbiturates

Determination of glycosilated haemoglobin (HbA1) has become an important parameter for the control of diabetes mellitus. Although several methods are available today, some are time consuming and complicated and may lead to differing results. Two methods, the thiobarbituric-acid (TBA) method and microcolumn chromatography, were compared with the reference method, high performance liquid chromatography (HPLC), with respect to precision, accuracy and practicability. Seventy different blood samples from diabetics were analysed. Using the TBA method, good results were achieved which were generally consistent with those of the reference method (r = 0.90); there were no significant differences in values determined with the two methods. However, the TBA method requires an inordinate amount of work. Microcolumn chromatography is better suited to the needs of physicians in private practice. Results with this method also correlate well with those of the reference method (r = 0.92) when the labile aldimine fraction has been removed by dialysis of the sample. Quality control can be performed using either lyophilized or deep-frozen control samples.

Topics: Chromatography; Chromatography, High Pressure Liquid; Diabetes Mellitus, Type 1; Glycated Hemoglobin; Humans; Thiobarbiturates

The influence of an eicosapentaenoic acid rich diet containing only 6,8 g cod liver oil daily for 2 weeks in 20 type I diabetics on fatty acid pattern in serum, platelet aggregation and thiobarbituric acid-reactive substances in serum were studied. There were increases in eicosapentaenoic acid portions in triglycerides, cholesterol esters and phospholipids of serum. This was associated with an inhibition of the platelet hyperaggregation, whereas platelet hyporeactivity is shifted to normal. Hyperreactivity of platelets from diabetics may be caused by enhanced TXA2 formation in comparison to healthy humans (1). On the other hand, diets rich in eicosapentaenoic acid inhibit platelet aggregation in healthy Volunteers (2,3). Therefore we investigated the dietary effect of relatively low doses of cod liver oil in diabetics type I on the eicosapentaenoic acid/arachidonic acid balance.

Topics: Adult; Cholesterol; Cod Liver Oil; Diabetes Mellitus, Type 1; Dietary Fats; Fatty Acids; Fish Oils; Glycated Hemoglobin; Humans; Lipids; Phospholipids; Platelet Aggregation; Thiobarbiturates

We describe here some useful modifications of the thiobarbituric acid (TBA) assay for measurement of nonenzymatic glucosylation of serum protein. The modified assay minimizes interference by glucose without a lengthy dialysis step, and does not require an independent blank determination. These modifications should make the TBA assay more convenient for evaluating glycemic control in diabetes. Serum protein is first precipitated with cold ethanol to remove endogenous glucose. The protein is then hydrolyzed in an oxalic acid solution to release glucose as hydroxymethylfurfural (HMF). The HMF is reacted with TBA to form a chromophore which is extracted into isobutanol for spectrophotometric analysis (lambda max = 435 nm). The absorbance at 435 nm is corrected by subtracting a blank reading at 500 nm, and the nmol HMF released is determined using a standard curve prepared with pure HMF. Normal values of this assay for both adults and children are 0.38 +/- 0.10 nmol HMF/mg serum protein (means +/- 2 SD). When the assay was applied to serum samples from a group of 39 Type I diabetic children more than 90% of the children exceeded the normal range of the assay.

Topics: Adolescent; Adult; Blood Proteins; Chemical Precipitation; Child; Diabetes Mellitus, Type 1; Furaldehyde; Humans; Hydrolysis; Methods; Reference Values; Spectrophotometry; Thiobarbiturates