1. On exposure of synovial fluid to superoxide and hydrogen peroxide, generated enzymically or by activated polymorphonuclear leucocytes, hyaluronic acid is depolymerized and the fluid loses its lubricating properties. The ability of synovial fluid from rheumatoid patients to scavenge superoxide and hydrogen peroxide was therefore examined. 2. Synovial fluid from a range of rheumatoid patients ...

Oxidative stress has been proposed to be a unifying cause for diabetic nephropathy and a target for novel therapies. Here we apply a new endogenous reductionoxidation (redox) sensor, hyperpolarized (HP) C dehydroascorbate (DHA), in conjunction with MRI to noninvasively interrogate the renal redox capacity in a mouse diabetes model. The diabetic mice demonstrate an early decrease in renal redox ...

Ascorbate free radical stimulates the growth of human promyelocytic leukemia cells (HL-60) in the presence of a limited amount of serum (1%) when added to the cells under conditions where it is impermeable. Maximum growth stimulation occurs at concentrations from 5 x 10(-9) to 2 x 10(-8) M. Ascorbate mimicks the stimulation effect of its free radical but stimulates at higher concentrations. Aut...

Control of stomatal aperture is of paramount importance for plant adaptation to the surrounding environment. Here, we report on several parameters related to stomatal dynamics and performance in transgenic tobacco plants (Nicotiana tabacum L., cv. Xanthi) over-expressing cucumber ascorbate oxidase (AO), a cell wall-localized enzyme of uncertain biological function that oxidizes ascorbic acid (A...

In addition to its well-known antioxidant properties, ascorbate (ASC) is capable of influencing normal cell cycle progression in plants. In this work we demonstrate that the oxidized molecule dehydroascorbate (DHA) is the active redox form in this respect. Our results indicate that the reduction of DHA might constitute the first step leading to this effect. During the last few years, evidence h...

// / The present investigation demonstrates the existence of NADH-dependent dehydroascorbate (DHA) recluctase activity in the soluble fraction of the rabbit lens. This DHA reductase was specific for NADH, and its apparent Km values for DHA and NADH were 5.7 mM and 4.0 uM, respectively. In a gel filtration of the lens soluble fraction on a Sephadex G-75 superfine column, the NADH-dependent DHA r...

Administration of 1 mM dehydroascorbate (DHA) results in a rapid and large increase in cellular ascorbate (AA) content in both Lupinus albus L. and Allium cepa L. root tips. Uptake of DHA from the medium occurs at a high rate within 10-12 h of incubation, and is slowed down thereafter. In the first few h, DHA reduction to AA is apparently correlated to GSH depletion and slightly higher DHA redu...

Abstract It has been widely assessed that the quality and quantity of nutrient supply growing system can strongly affect growth development plants, nutritional quality, levels minerals, phytochemicals, vitamins. The study was conducted on leaves wild rockets grown in soil soilless to examine effect conditions mineral fertilization doses content, enzymatic non-enzymatic antioxidants, oxidative s...

When drought occurs during the maize-filling period, probability of yield decline increases. Abscisic acid (ABA) plays a regulatory role in physiological and metabolic activities plant development. However, its effect on antioxidant system maize leaves grain-filling stage is unclear. Maize plants (Zhengdan958) were used as an experimental material, ABA was sprayed stage. The placed under condit...