Cancer progression is characterized by loss of extracellular matrix (ECM) integrity, which is a precondition for tumor growth and metastasis. In order to elucidate the precise mechanisms of ECM degradation in cancer we used a genetically modified mouse mimicking two distinct human metabolic features associated with carcinogenesis, the lack of endogenous vitamin C synthesis and the production of...

The mode of coordination of8 manganese(fI), cobaltm, nickel(H), copper(II), zinc(H), lead(II) and cadmium(I1) to sodium ascorbate (NaHAsc) was investigated using IR, UV-visible, AAS, elemental microanalyzer, conductivity, magnetic and 'M and I3C NMR spectroscopic studies, NaNAsc is bidentate and coordination was through the carbonyl group and the oxygen atom of carbon-2 enolic hydfoxyl grou...

Phytic acid (PA) has been recognized as a potent antioxidant and inhibitor of iron-catalyzed hydroxyl radical formation under in vitro and in vivo conditions. Therefore, the aim of the present study was to investigate, with the use of HPLC/MS/MS, whether PA is capable of inhibiting linoleic acid autoxidation and Fe(II)/ascorbate-induced peroxidation, as well as Fe(II)/ascorbate-induced lipid pe...

The imposition of environmental stresses on plants brings about disturbance in their metabolism thereby negatively affecting their growth and development and leading to reduction in the productivity. One of the manifestations of different abiotic and biotic stress conditions in plants is the enhanced production of reactive oxygen species (ROS) which can be hazardous to cells. Therefore, in orde...

Organisms using oxygen for aerobic respiration require antioxidants to balance the production of reactive oxygen species during metabolic processes. Various species--including humans and other primates--suffer mutations in the GULO gene encoding L-gulono-γ-lactone oxidase; GULO is the rate-limiting enzyme in the biosynthesis of ascorbate, an important cellular antioxidant. Animals lacking the a...

Switchgrass (Panicum virgatum L.) is being developed as a bioenergy species. Recently an early version of its genome has been released permitting a route to the cloning and analysis of key proteins. Ascorbate peroxidases (APx) are an important part of the antioxidant defense system of plant cells and present a well studied model to understand structure-function relationships. Analysis of the ge...

We studied two unrelated individuals with Ehlers-Danlos syndrome type VI, which is characterized by congenital hypotonia, lax joints, severe kyphoscoliosis, friable skin, and hemorrhagic hypotrophic scars. The diagnosis was confirmed by decreased hydroxylysine residues in dermal collagen and decreased collagen lysyl hydroxylase activities in their cultured skin fibroblasts. Despite the diminish...

Reaction of potassium dichromate with sodium ascorbate was studied by EPR spectroscopy at room temperature, in 0.10 M N-[2-hydroxyethyl]piperazine-N'-[2-ethanesulfonic acid] (HEPES), phosphate, cacodylate, and tris(hydroxymethyl)aminomethane hydrochloride (Tris.HCl) buffers at pH 7.0, in the presence of 0.10 M spin trap [5,5-dimethyl-1-pyrroline 1-oxide or 2-methyl-N-(4-pyridinylmethylene)-2-pr...

The measurement of oxalate in urine and plasma continues to be difficult, particularly in the presence of ascorbate. We have modified and validated a colorimetric assay involving the use of oxalate oxidase (EC 1.2.3.4). Modification of an HPLC spectrophotometric detector improved sensitivity (to as much as 1000-fold that of conventional spectrophotometers) and allowed measurement of oxalate con...

introduction: in the present investigation, we aimed to study the effect of different concentrations of ascorbate/vitamin c, on membrane integrity, viability, and acrosome reaction of human spermatozoa in presence of ferrous (fe2+) ions as lipid peroxidation (lpo) promoter. material and methods: we used 12 semen samples from healthy donors in shahrekord. the samples were then washed twice with ...