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Results 401 - 450 of 2377
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Chen Yuan-Hua - - 2006
Lipopolysaccharide (LPS) has been associated with adverse developmental outcomes including embryonic resorption, intra-uterine fetal death (IUFD), intra-uterine growth retardation (IUGR) and preterm labor. Reactive oxygen species (ROS) mediate LPS-induced developmental toxicity. Ascorbic acid is an antioxidant. In the present study, we investigated the effect of ascorbic acid on LPS-induced IUFD ...
Choi Ka Y - - 2006
To increase the extent of comparative oral bioavailability (F) value and the diuretic and natriuretic effects of orally administered azosemide, ascorbic acid was coadministered to rats. The rationales for this study are that ascorbic acid might inhibit intestinal first-pass effect of azosemide and might increase the unionized fraction of azosemide ...
Pfanzagl Beatrix - - 2005
Metal-catalyzed LDL oxidation is enhanced by the presence of homocysteine. In this study, the effectiveness of ascorbic acid against low-density lipoprotein (LDL) oxidation by iron(III) and copper(II) in the presence of homocysteine and the main plasma disulfide cystine was investigated. Relative to the degree of LDL oxidation reached in the ...
Rezaei Behzad - - 2005
A simple and sensitive spectrofluorometric method was developed for the simultaneous determination of ascorbic acid and cysteine by a flow-injection system. This method is based on the reduction of Tl(III) with ascorbic acid or cysteine in acidic media, producing fluorescence reagent, TlCl3(2-) (lambdaex = 227 nm, lambdaem = 419 nm). ...
Siddique Yasir Hasan - - 2005
In our present study, different doses of allicin and L-ascorbic acid were tested against the genotoxic damage induced by chlormadinone acetate (CMA; 40 microM) using chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs) as the parameters. Treatment with allicin and L-ascorbic acid resulted in reduction of CAs and SCEs. The ...
Deaton Christopher M - - 2005
Effects of acute airway inflammation induced by organic dust inhalation on pulmonary antioxidant status were investigated in healthy horses and horses affected by recurrent airway obstruction. Exposure to organic dust induced acute airway neutrophilia, which was associated with increases in elastase and decreases in ascorbic acid concentrations in bronchoalveolar lavage ...
Esteve M J - - 2005
The effects of the physicochemical and quality characteristics of various minimally pasteurized refrigerated orange Spanish juices and their changes with storage time and temperature were investigated. Essential oils, acidity, conductivity, diacetyl index, hydroxymethylfurfural, formol index, viscosity and ascorbic acid varied with storage time more significantly at 10 degrees C than ...
May James M - - 2005
To test whether ascorbic acid might be involved in the antioxidant defenses of inflammatory cells, we studied ascorbate uptake and recycling by quiescent and lipopolysaccharide-activated RAW264.7 murine macrophages. These cells concentrated ascorbate 100-fold in overnight culture, achieving steady-state concentrations of more than 10 mM at extracellular concentrations of 20-100 muM. ...
Suber Lorenza - - 2005
Uniform, well-dispersed silver particles of various morphologies have been prepared by reducing highly acidic silver nitrate solutions with ascorbic acid in the presence of a sodium naphthalene sulfonate-formaldehyde copolymer as dispersing agent. By varying the temperature of the reaction, the free acid content, the addition rate of the reductant, and ...
Rümelin A - - 2005
BACKGROUND: A reduction of plasma ascorbic acid concentration in the post-operative period has been well documented and is associated with an increase in post-operative complications. The underlying reason for the decreased concentration of ascorbic acid in the plasma is not clear. However, only an increased post-operative requirement for ascorbic acid ...
Lestari F - - 2005
Fire combustion products contain a broad range of chemicals, which have a multitude of possible toxic interactions in humans. The aim of this study was to evaluate the cytotoxicity of selected substances commonly produced during fire combustion. A range of human cell lines and cultures including: skin fibroblasts, HepG2 (liver ...
Trommer Hagen - - 2005
This study is the continuation of our research into vitamin C and its possible effects on human skin after topical administration. The effects of ascorbic acid, iron ions and UV irradiation on stratum corneum lipid models were investigated. The lipid models used were: a simple system (linolenic acid dispersion), a ...
Wolucka Beata A - - 2005
Vitamin C (L-ascorbic acid) is an important primary metabolite of plants that functions as an antioxidant, an enzyme cofactor, and a cell-signalling modulator in a wide array of crucial physiological processes, including biosynthesis of the cell wall, secondary metabolites and phytohormones, stress resistance, photoprotection, cell division, and growth. Plants synthesize ...
Kuzkaya Nermin - - 2005
It has been suggested that uric acid acts as a peroxynitrite scavenger although it may also stimulate lipid peroxidation. To gain insight into how uric acid may act as an antioxidant, we used electron spin resonance to study the reaction of uric acid and plasma antioxidants with ONOO-. Peroxynitrite reacted ...
Tsai Pi-Ju - - 2005
Ascorbic acid plays important roles in mammalian central nervous system. We employed an on-line analytical system to monitor the extracellular ascorbic acid concentrations in anesthetized rat spinal cord before and after the experimental injury. A microdialysis probe (216 microm od, 200 microm id, 3 mm in length) was implanted into ...
Zhang Lei - - 2005
Aspartic acid was covalently grafted on to a glassy carbon electrode (GCE) by amine cation radical formation in the electrooxidation of the amino-containing compound. X-ray photoelectron spectroscopic (XPS) measurement and cyclic voltammetric experiments proved the aspartic acid was immobilized as a monolayer on the GCE. Electron transfer to Fe(CN)6(4-) in ...
Szymula Marta - - 2005
The rheological properties of the microemulsion region of the SDS, pentanol, and water micellar system have been studied experimentally. The W/O and O/W microemulsions behave as typical Newtonian fluids: viscosity remains constant independent of the shear rate. For the bicontinuous system the shear-thinning effect is observed. The addition of ascorbic ...
Mur Luis A J - - 2005
We demonstrate the use of laser photoacoustic detection (LPAD) as a highly sensitive method to detect in planta nitric oxide ((*)NO) production from tobacco (Nicotiana tabacum). LPAD calibration against (*)NO gas demonstrated a linear relationship over 2 orders of magnitude with a detection threshold of <20 pmol h(-1) (1 part ...
McNulty Amy L - - 2005
Collagen II is the major protein component of articular cartilage and forms the collagen fibril network, which provides the tensile strength of cartilage. Collagen II synthesis is enhanced by ascorbic acid (vitamin C) at both a transcriptional and post-transcriptional level. While the importance of ascorbic acid in the synthesis of ...
Niranjan M H - - 2005
A method to produce encapsulatable units for synthetic seeds was developed in L. indica. Somatic embryos were harvested from leaf derived embryogenic callus on Murashige and Skoog's basal medium supplemented with 2, 4-dichlorophenoxy acetic acid (2, 4-D, 0.5 mg/l), 6-benzyl amino purine (BAP, 1 mg/l) and ascorbic acid (AA, 50 ...
Doeller Jeannette E - - 2005
The role of nitric oxide (NO) in redox cell signaling is widely accepted. However, the biological role of another candidate small inorganic signaling molecule and the subject of this study, hydrogen sulfide (H2S), is much less known. H2S as a reductant and nucleophile has numerous potential cellular targets; however, its ...
Budhwar Roli - - 2005
The parenteral administration of alpha-lipoic acid (LA) protected against chromate induced oxidative stress in mouse liver. A shift in Cr induced pro-oxidant state to antioxidant-state by LA was noteworthy. The degree of protection was significant and similar in different LA administration regimens (prior-, co- and post- parenteral Cr exposure) explored. ...
Levine Robert A - - 2005
Surveys determining amounts of acrylamide formed as a byproduct of cooking in frequently consumed fried and baked foods have sometimes found variability in the levels, even when comparing items having similar ingredients and cooking procedures. To better understand the sources of variability, the effects of different ingredients on formation and ...
Lu Qing - - 2005
Manifestations of vascular disease, including microvascular changes, constitute the major part of the morbidity and mortality in diabetic patients. Oxidative stress has been suggested to play an important role in the vascular dysfunction of diabetic patients. Furthermore, epidemiological observations indicate a beneficial effect of an increased dietary intake of antioxidants. ...
Sabzi Reza Emamali - - 2005
An electrochemically prepared thin film of cobalt pentacyanonitrosylferrate (GC/CoPCNF) was used as a surface modifier for glassy carbon electrodes. The oxidation of ascorbic acid on a glassy carbon electrode modified with GC/CoPCNF as a working electrode was studied using cyclic voltammetry, rotating disk electrode (RDE) voltammetry and chronoamperometry in a ...
Argirov O K - - 2005
Previous studies from this laboratory have shown that ultraviolet A (UVA) light can bleach the yellow advanced glycation end products (AGEs) of aged and cataractous human lenses. The AGEs OP-lysine and argpyrimidine are two UVA-absorbing posttranslational modifications that are abundant in the eye lens. The purpose of this study was ...
Pandey P C - - 2005
We report herein the preparation of few chemically sensitized organically modified sol-gel glass (ormosil) films and sensing of dopamine at the surface of the modified electrodes derived from these films. The chemical sensitization in ormosil-modified electrodes is introduced by incorporating: (a) potassium ferricyanide and (b) either Nafion, or dibenzo-18-crown-6 or ...
Leizerson Shirly - - 2005
Electrical heating of food products provides rapid and uniform heating, resulting in less thermal damage to the product. The objective of this research was to examine the effects of ohmic heating on the stability of orange juice with comparison to conventional pasteurization. During storage at 4 degrees C, degradation curves ...
Kato Takeshi - - 2005
Chemiluminescence (CL) was immediately observed after an iron-chlorophyllin aqueous solution was added to an acetonitrile/water mixed solution containing hydrogen peroxide. Quenching of the iron-chlorophyllin complex CL was caused by adding L-ascorbic acid. Based on these facts, a determination method involving small amounts of L-ascorbic acid was developed. As a result, ...
Doran Gregory - - 2005
Anaerobic water samples containing levels of soluble Fe(II) may form insoluble Fe(III) particulates that could hinder subsequent extraction and analysis. Solid-phase extraction (SPE) cartridges could become blocked by this material, reducing the volume that can be processed. The ability of ascorbic acid to reduce these Fe(III) colloids and/or to prevent ...
Mullan Brian A - - 2005
1. Acute hyperglycaemia may impair endothelial function. Ascorbic acid (AA), administered intra-arterially, has been reported to improve endothelium-dependent vasodilatation during a forearm hyperglycaemic clamp. Using a randomized, double-blind, placebo-controlled, cross-over study, we investigated the potential for intravenous ascorbic acid to modify the endothelial response to acute systemic hyperglycaemia in humans. ...
Abdulmajed Kasem - - 2005
The free radical scavenging properties of retinyl ascorbate (RA-AsA) were determined by monitoring the decomposition of 2,2-diphenyl-1-picrylhydrazyl (DPPH) as a function of time and in comparison with ascorbic acid (AsA), ascorbic acid palmitate (AsA-Pal), retinoic acid (RA), retinol (ROL) and retinol palmitate (Rol-Pal). The rate constant of RA-AsA (mean3+/-SD) was ...
Giuntini Deborah - - 2005
The aim of the present study was to investigate if the depletion of UV-B radiation affected the most representative carotenoids as well as the ascorbic acid content in tomato fruits, harvested at both breaker and firm red stages. To do this, three tomato genotypes, DRW 5981, HP 1, and Esperanza, ...
Mukherjee Amitava - - 2005
In this work the effect of organic reducing reagents, namely, ascorbic acid, oxalic acid and L-cysteine on dissolution of commercial TiO(2) has been investigated. Kinetic studies showed that a maximum of about 45% of TiO(2) was dissolved by ascorbic acid in 4h when oxide:acid molar ratio was kept at 1:2. ...
Erdogan Zeynep - - 2005
The effects of cadmium on performance, antioxidant defense system, liver and kidney functions, and cadmium accumulation in selected tissues of broiler chickens were studied. Whether the possible adverse effects of cadmium would reverse with the antioxidant ascorbic acid was also investigated. Hence, 4 treatment groups (3 replicates of 10 chicks ...
Savini Isabella - - 2005
In skeletal muscle, vitamin C not only enhances carnitine biosynthesis but also protects cells against ROS generation induced by physical exercise. The ability to take up both ascorbic and dehydroascorbic acid from the extracellular environment, together with the ability to recycle the intracellular vitamin, maintains high cellular stores of ascorbate. ...
de Sousa Marcio Goncalves - - 2005
AIM: To compare the acute effects of ascorbic acid on vasodilation of veins and arteries in vivo. METHODS: Twenty-six healthy non-smokers and 23 healthy moderate smokers were recruited in this study. The dorsal hand vein compliance technique and flow-mediated dilation were used. Dose-response curves to bradykinin and sodium nitroprusside were ...
Dalvit G - - 2005
In vitro culture results in higher oxygen concentrations than in vivo environments, leading to an increased level of reactive oxygen species (ROS) that cause lipid peroxidation of cellular membranes. Alpha-tocopherol (active form of vitamin E) is an antioxidant that protects mammalian cells against lipid peroxidation, which is regenerated by ascorbic ...
Rassam Maysoon - - 2005
Ascorbic acid and total oxalate were measured in fruit from six genotypes of Actinidia chinensis. Ascorbic acid was separated from oxalate in fruit extracts by HPLC and quantified from absorbance at 245 nm, whereas oxalate was measured enzymatically in the HPLC eluate. Levels of whole fruit mean ascorbic acid in ...
Sugisawa Teruhide - - 2005
Ketogulonicigenium vulgare DSM 4025, known as a 2-keto-L-gulonic acid producing strain from L-sorbose via L-sorbosone, surprisingly produced L-ascorbic acid from D-sorbitol, L-sorbose, L-gulose, and L-sorbosone as the substrate under a growing or resting condition. As the best result, K. vulgare DSM 4025 produced 1.37 g per liter of L-AA from ...
Feng Suling - - 2005
A highly sensitive spectrofluorimetric method is proposed for the determination of trace amount of ascorbic acid using a new indication. The method is based on the inhibition of ascorbic acid on the oxidation of pyronine Y (PRY) by nitrite. The detection limit for ascorbic acid is 0.012 microg ml(-1), the ...
Dupertuis Yves M - - 2005
BACKGROUND: The recent development of multilayered bags has minimized ascorbic acid oxidation in parenteral nutrition (PN) admixtures. However, the gas-barrier property of multilayered bags depends on their plastic material. This study compared ascorbic acid stability in different multilayered bags under experimental conditions. METHODS: Oxygen permeability of a newly developed 6-layered ...
Pavlov Atanas I - - 2005
The all-round effect of dissolved oxygen concentration, agitation speed, and temperature on the rosmarinic acid production by Lavandula vera MM cell suspension was studied in a 3-L laboratory bioreactor by means of the modified Simplex method. Polynomial regression models were elaborated for description of the process of rosmarinic acid production ...
Hsu Cheng-Chin - - 2005
Human umbilical vein endothelial cells (HUVECs) were used to investigate the individual effect of ascorbic (0.01 and 0.05 mM) and uric acid (3, 5, and 7 mg/dl), as well as the combined effect of these two agents on glucose-induced overexpression of fibronectin (Fn), glutathione peroxidase (GPx) activity, H2O2 level and ...
Lévêque Nathalie - - 2005
Ultraviolet irradiation causes adverse effects like sunburn, photosensitivity reactions or immunologic suppression. The aim of this study was to evaluate the photo-protective outcome of a sunscreen cream (SPF8) by the determination of erythema indexes and the assessment of ascorbic acid and its metabolites in human dermis. These substances were used ...
Yamamoto Katsunobu - - 2005
An amperometric glucose ring-disk biosensor based on a ruthenium complex mediator of low redox potential was fabricated and evaluated. This thin-layer radial flow microsensor (10mul) with ring-disk working electrode displayed remarkable amperometric sensitivity. For Ru(3)(mu(3)-O)(AcO)(6)(Py)(3)(ClO(4)) (Ru-Py), a trinuclear oxo-acetate bridged cluster, a reversible redox curve of low redox potential and ...
Tang Yajun - - 2005
A method of quickly determining ascorbic acid and sorbic acid by capillary zone electrophoresis with ultraviolet detection was developed. The choice of background electrolyte, wavelength, injection time and applied voltage were discussed. Ascorbic acid and sorbic acid were well separated in 80mmolL(-1) boric acid-5mmolL(-1)borax (pH = 8.0) in 5min at ...
Dogan Serap - - 2005
In this study, the polyphenol oxidase (PPO) of artichoke (Cynara scolymus L.) was first purified by a combination of (NH(4))(2)SO(4) precipitation, dialysis, and a Sepharose 4B-L-tyrosine-p-aminobenzoic acid affinity column. At the end of purification, 43-fold purification was achieved. The purified enzyme migrated as a single band on sodium dodecyl sulfate-polyacrylamide ...
Koliou Eleftheria K - - 2005
The catalytic system Cu(AcO)2-pyridine 1:4 mol% in methanol, slowly catalyses the air oxidation of ascorbic acid to the 2-methyl hemi-ketal of dehydroascorbic acid 5, and hydrogen peroxide. However, with Cu(AcO)2-pyridine 3:4 mol% the air oxidation is quite fast and no hydrogen peroxide is present at the end of the reaction. ...
Ramos Luiz Antônio - - 2005
The preparation and electrochemical characterization of a carbon paste electrode modified with bis(N,N-piperidinedithiocarbamate)-mu-tris(N,N-piperidinedithiocarbamate)diruthenium(III) complex, alpha-[Ru2(Pip)5]Cl are described. The best voltammetric response was obtained for a 10% (m/m) alpha-[Ru2(Pip)5]Cl content in the paste, potassium acid phthalate solution pH 4.0 as supporting electrolyte and scan rate of 100 mV s-1. The analytical ...
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