ascorbic-acid and acetoacetic-acid

Diastereomeric ratios of >95 : 5 were obtained when performing methylene transfers onto imines originating from d-mannitol and (S)-(-)-2-methyl-2-propane sulfinamide or ascorbic acid and (R)-(-)-2-methyl-2-propane sulfinamide.

Topics: Acetoacetates; Amides; Ascorbic Acid; Imines; Mannitol; Methane; Stereoisomerism; Substrate Specificity

A disturbed embryonic antioxidant defense mechanism may play a major role in diabetes-induced teratogenesis. We therefore studied the antioxidant capacity of 10.5-day-old rat embryos and their yolk sacs after culture for 28 hr in vitro under diabetic conditions (3 mg/ml glucose, 2 mg/ml beta-hydroxybutyrate (BHOB) and 10 microg/ml of acetoacetate), as compared with control embryos in vitro. We found a high rate of congenital anomalies, decreased growth and protein content, and a decrease in the activity of both superoxide dismutase (SOD) and catalase (CAT) under diabetic conditions, as compared with controls. The reducing power, which reflects the concentration and type of water-soluble and of lipid-soluble low-molecular-weight antioxidants (LMWA), was measured by cyclic voltammetry. Generally, LMWA were reduced in the embryos and yolk sacs under diabetic conditions. In the water-soluble fraction of control embryos and yolk sacs, two peak potentials were found, indicating two major groups of LMWA, while only one peak potential was found under diabetic conditions, indicating that an entire group of LMWA is missing. HPLC studies have demonstrated a decrease in vitamin C (water-soluble fraction) and in vitamin E (lipid-soluble fraction) under diabetic culture conditions, and an increase in uric acid. Generally, the concentration of LMWA was higher in the embryos than in the yolk sac. LMWA concentration, protein content, and antioxidant enzyme activity were lower in the malformed experimental embryos than in experimental embryos without anomalies. The addition of vitamins C and E to the diabetic culture medium abolished the deleterious effects of the diabetic serum on the embryos. The disturbed antioxidant defense mechanism under diabetic conditions may be explained, at least in part, by a direct effect of diabetic metabolic factors on the activity of antioxidant enzymes and on the concentration of reducing equivalents. This, in turn, may be embryotoxic.

Topics: 3-Hydroxybutyric Acid; Acetoacetates; Animals; Antioxidants; Ascorbic Acid; Catalase; Congenital Abnormalities; Culture Media; Embryo, Mammalian; Female; Glucose; Models, Biological; Organ Culture Techniques; Pregnancy; Pregnancy in Diabetics; Rats; Superoxide Dismutase; Uric Acid; Vitamin E; Yolk Sac

The pyridine nucleotide specificity, the participation of delta psi, and the energy-linked transhydrogenase in the process of Ca2+ efflux stimulated by the oxidized state of NAD(P) were examined in rat liver mitochondria energized by ascorbate + TMPD. The following observations were made: The Ca2+ efflux rate is independent of the redox state of mitochondrial NAD, but is at a minimum when mitochondrial NADP is in the reduced state and accelerated several-fold when it is in the oxidized state. When the redox state of NADP is shifted to a more oxidized state, the steady-state level of Ca2+ in the medium increased and delta psi decreased in proportion to the mitochondrial NADP+ level. The activity of the energy-linked NAD(P) transhydrogenase seems to be a key element in determining the redox state of NADP and thus of Ca2+ retention and efflux from mitochondria.

Topics: Acetoacetates; Animals; Ascorbic Acid; Calcium; Electron Transport; Kinetics; Male; Membrane Potentials; Mitochondria, Liver; NADP; NADP Transhydrogenases; Oxidation-Reduction; Rats; Rats, Inbred Strains; Spectrometry, Fluorescence; Tetramethylphenylenediamine

Results for urinary glucose by the Boehringer Mannheim BM33071 test pad and a hexokinase-based method agree well. The new test, which involves the glucose oxidase/peroxidase reaction, measures as little as 260 mg of glucose per liter. Acetoacetate, beta-hydroxybutyrate, and human hemoglobin do not interfere.

Topics: 3-Hydroxybutyric Acid; Acetoacetates; Ascorbic Acid; Evaluation Studies as Topic; Glucosephosphate Dehydrogenase; Glycosuria; Hemoglobinuria; Hexokinase; Humans; Hydroxybutyrates; Indicators and Reagents; Reagent Strips

Topics: Acetoacetates; Ascorbic Acid; Carbohydrate Metabolism; Fabaceae; Germination; Glucose

Topics: Acetoacetates; Ascorbic Acid; Carbohydrate Metabolism; Fabaceae; Folic Acid; Germination; Glucose; Phaseolus; Vitamin B Complex; Vitamins

Topics: Acetoacetates; Ascorbic Acid; Carbohydrate Metabolism; Fabaceae; Germination; Glucose; Phaseolus

Topics: Acetoacetates; Animals; Ascorbic Acid; Biomedical Research; Dehydroascorbic Acid; Diabetes Mellitus, Experimental; Glucose; Vitamins

Topics: Acetoacetates; Ascorbic Acid; Biomedical Research; Dehydroascorbic Acid; Glucose; Vitamins

Topics: Acetoacetates; Animals; Ascorbic Acid; Biomedical Research; Dehydroascorbic Acid; Diabetes Mellitus, Experimental; Glucose; Sodium; Vitamins

Topics: Acetoacetates; Adrenal Cortex; Ascorbic Acid; Carbohydrate Metabolism; Cholesterol; Guinea Pigs; Lipid Metabolism

Topics: Acetoacetates; Ascorbic Acid; Biomedical Research; Humans; Insulin; Lactic Acid; Vitamins