A double-masked study of the effects of topical ascorbate on alkali burns utilized 37 rabbit eyes subjected to 20 sec, 12 mm, IN sodium hydroxide burns. Preliminary studies established the ocular acceptability, penetrability, and stability of the solutions used. Eighteen eyes in the experimental group were given two drops of10% ascorbate in Adsorbotear vehicle hourly for 14 hr of each day. Nine...

BACKGROUND Vitamin C (ascorbate) is likely to be essential for skeletal muscle structure and function via its role as an enzyme cofactor for collagen and carnitine biosynthesis. Vitamin C may also protect these metabolically active cells from oxidative stress. OBJECTIVE We investigated the bioavailability of vitamin C to human skeletal muscle in relation to dietary intake and plasma concentra...

The present investigation addresses the problem of the binding mode of phenolic inhibitors and the substrate ascorbate to the active site of ascorbate oxidase. The results from both types of compounds indicate that the binding site is located in a pocket near the type 1 copper center. This information is of general interest for blue multicopper oxidases. Docking calculations performed on the as...

We used constant potential in vivo voltammetry to measure changes in striatal ascorbate in the rat in response to i.p. administration of several non-volatile anaesthetics. Propofol and pentobarbitone, which enhance GABA-mediated neuronal inhibitions, decreased ascorbate current to 27.0 (SEM 7.4) % and 46 (6) % of control, respectively. Chloral hydrate, diazepam alone or with ketamine, and fenta...

Earlier work (2) demonstrated that low, but not high, concentrations of ascorbate produce a swelling or lytic change in dilute suspensions of isolated liver mit.ochondria. This structural change shows both similarities to and differences from the phosphate-induced, electron transport-dependent swelling which has been rather extensively investigated (3-6). Both phenomena require O2 and can be pr...

Information on dimethyl nitrosamine (DMN)-induced toxicity on endocrine functions is still scanty. This study therefore investigated the outcomes of DMN-induced toxicity on endocrine (thyroid and reproductive) functions, as well as kallikrein-3 level, and effects of ascorbate treatments in male wistar rats. Thirty animals divided into six groups of five rats each were used. Group I animals were...

Previous work from our laboratory demonstrated that pyridoxal isonicotinoyl hydrazone (PIH) has in vitro antioxidant activity against iron plus ascorbate-induced 2-deoxyribose degradation due to its ability to chelate iron; the resulting Fe(III)-PIH(2) complex is supposedly unable to catalyze oxyradical formation. A putative step in the antioxidant action of PIH is the inhibition of Fe(III)-med...

Previously, we showed that in barley (Hordeum vulgare) leaves with heat-inactivated oxygen-evolving complexes, photosystem II (PSII) has access to a large pool of alternative electron donors. Based on in vitro data, we proposed that this donor was ascorbate, yet this hypothesis has not been substantiated in vivo. In this paper, with the aid of chlorophyll a fluorescence induced by short (5-ms) ...

Peroxynitrite (ONOO(((-)))/ONOOH) is expected in vivo to react predominantly with CO(2), thereby yielding NO(2)(.) and CO(3) radicals. We studied the inhibitory effects of ascorbate on both NADH and dihydrorhodamine 123 (DHR) oxidation by peroxynitrite generated in situ from 3-morpholinosydnonimine N-ethylcarbamide (SIN-1). SIN-1 (150 micrometer)-mediated oxidation of NADH (200 micrometer) was ...