Search results for "ascorbic acid"
showing 10 items of 295 documents
Effect of a two-year supplementation with low doses of antioxidant vitamins and/or minerals in elderly subjects on levels of nutrients and antioxidan…
1997
Eighty-one elderly hospitalized subjects (65 years) were recruited for a double-blind placebo-controlled study to examine low dose supplementation of antioxidant vitamins and minerals on biological and functional parameters of free radical metabolism. Subjects were randomly assigned to one of the four treatment groups, daily receiving for 2 years: placebo group; mineral group: 20 mg zinc, 100 micrograms selenium; vitamin group: 120 mg vitamin C (Vit C), 6 mg beta-carotene (beta CA), 15 mg vitamin E (Vit E); mineral and vitamin group: Zn 20 mg, Se 100 micrograms, Vit C 120 mg, beta CA 6 mg, Vit E 15 mg.Fifty-seven subjects completed the study. A large frequency of Vit C, Zn and Se deficienci…
Effects of β-Carotene, Retinal, Riboflavin, α-Tocopherol and Vitamins C and K1 on Sister-chromatid Exchanges Induced by 3-Amino-1-methyl-5H-pyrido[4,…
1998
The vitamins and related compounds cited in the title were investigated for their abilities to modulate sister-chromatid exchanges (SCEs) induced by Trp-P-2 or cyclophosphamide (CP) in human peripheral lymphocyte cultures in the presence of an exogenous metabolizing system from rat liver. When inducer and test substances were given simultaneously, beta-carotene, retinal and alpha-tocopherol caused a dose-dependent decrease of SCE frequencies induced by Trp-P-2 and CP. Vitamin K1, however, brought about an identical effect with Trp-P-2 only, while with CP an initial decrease of SCEs was followed by a statistically significant re-increase at higher concentrations. Vitamin C was ineffective ag…
Dietary antioxidant supplementation did not affect declining sperm function with age in the mouse but did increase head abnormalities and reduced spe…
1998
The present study aims to ascertain whether dietary administration of a mixture of vitamins C and E may prevent the negative effects of paternal age on male fertility variables in the mouse. Experimental males were fed a standard diet supplemented with either a low or high dose of vitamins C and E. Oocytes enclosed in cumulus masses were inseminated using a 2 x 2 factorial design established according to whether males were young (3-4 months of age) or aged (22-24 months of age) and whether they were fed a control or antioxidant diet. Aged males showed a significant decrease in number of spermatozoa/mg epididymis when compared to young males. Dietary supplementation with low doses of vitamin…
Inverse association of vitamin C with cataract in older people in India.
2011
OBJECTIVE: To examine the association between vitamin C and cataract in the Indian setting. DESIGN: Population-based cross-sectional analytic study. PARTICIPANTS: A total of 5638 people aged ≥60 years. METHODS: Enumeration of randomly sampled villages in 2 areas of north and south India to identify people aged ≥60 years. Participants were interviewed for socioeconomic and lifestyle factors (tobacco, alcohol, household cooking fuel, work, and diet); attended a clinical examination, including lens photography; and provided a blood sample for antioxidant analysis. Plasma vitamin C was measured using an enzyme-based assay in plasma stabilized with metaphosphoric acid, and other antioxidants wer…
Association between a SLC23A2 gene variation, plasma vitamin C levels, and risk of glaucoma in a Mediterranean population
2011
Purpose Several dietary factors have been associated with glaucoma. Among them, dietary antioxidant intake (i.e., vitamin C and vitamin A) in association with glaucoma has been analyzed, but with mixed results. Genetic factors may play a role in modulating the effect of dietary antioxidant intake on glaucoma; however, nutrigenetic studies in this field are scarce. Our aim was to study the association between selected polymorphisms in key proteins related to vitamin C and vitamin A concentrations and primary open-angle glaucoma (POAG). Methods We performed a case-control study matched for age, sex, and bodyweight. We recruited 300 subjects (150 POAG cases and 150 controls) from a Mediterrane…
Changes inα-tocopherol and retinol levels during cardiopulmonary bypass correlate with maximal arterial partial pressure of oxygen
2007
Cardiopulmonary bypass (CPB) is associated with oxidative stress. This study examined antioxidant levels in adults undergoing CPB surgery and their correlation with clinical variables. Arterial blood samples were obtained from 27 patients undergoing CPB. The time-course variation of vitamin C (spectrofluorimetry), alpha-tocopherol and retinol (HPLC) levels were determined. Plasma vitamin C rose initially but gradually decayed during reperfusion until 60% reduction of baseline values post-surgery. alpha-Tocopherol and retinol were reduced along CPB with post-operative values approximately 25% lower than baseline. No significant changes were found for selenium and glutathione peroxidase. PaO(…
Changes in lipid metabolism and antioxidant defense status in spontaneously hypertensive rats and Wistar rats fed a diet enriched with fructose and s…
2005
Abstract Objective Larger doses of fructose and saturated fat have been associated with oxidative stress and development of hypertension. The effects of modest amounts of fructose and saturated fatty acids on oxidative stress are unknown. Methods To increase knowledge on this question, 10-wk-old spontaneously hypertensive rats and Wistar rats were fed for 8 wk with a control diet or an experimental diet enriched with fructose (18%) and saturated fatty acids (11%; FS diet). The total antioxidant status of organs and red blood cells was assayed by monitoring the rate of free radical-induced red blood cell hemolysis. Sensitivity of very low-density lipoprotein and low-density lipoprotein (VLDL…
Effect of dietary supplementation with a mixture of Vitamins C and E on fertilization of tertiary butyl hydroperoxide-treated oocytes and parthenogen…
2002
The present study aims to analyze the effect of dietary supplementation with a mixture of Vitamins C and E on fertilization and later development of tertiary butyl hydroperoxide (tBH)-treated mouse oocytes and on parthenogenetic activation of freshly ovulated mouse oocytes. We fed hybrid mice a standard diet supplemented or not supplemented with Vitamins C and E from the first day of weaning until the age of 12 weeks. We noted no significant effect of diet on fertilization rate, percentage of total and hatching blastocysts, total number of cells, mitotic index and percentage of apoptotic nuclei at 120 h post-insemination of oocytes incubated for 15 min in the presence of 0, 1, 5 and 10 micr…
Vitamin C supplementation does not improve hypoxia-induced erythropoiesis.
2012
Martinez-Bello,Vladimir E., Fabian Sanchis-Gomar, Daniel Martinez-Bello, Gloria Olaso-Gonzalez, Mari Carmen Gomez-Cabrera, and Jose Viña. Vitamin C Supplementation Does Not Improve Hypoxia-Induced Erythropoiesis. High Alt Med Biol 13:269–274, 2012.—Hypoxia induces reactive oxygen species production. Supplements with antioxidant mixtures can compensate for the decline in red cell membrane stability following intermittent hypobaric hypoxia by decreasing protein and lipid oxidation. We aimed to determine whether supplementation with vitamin C is implicated in the regulation of erythropoiesis and in the oxygen-carrying capacity of the blood, and also whether antioxidant supplementation prevents…
Mass Transport in Nanoporous Gold and Correlation with Surface Pores for EC 1 Mechanism: Case of Ascorbic Acid
2021
International audience; Entry for the Table of Contents Playing with the pores: Surface pores size in nanoporous gold modulates the electrode reactions pathways of ascorbic acid. The reaction is largely driven by diffusion when pores are smaller (nanometer). On the contrary, adsorption holds the key role when pores are bigger (micrometer), allowing permeation of molecules in the film volume.