Search results for "oxidation"
showing 10 items of 1913 documents
Retinol oxidation to retinoic acid in human thyroid glandular cells.
2014
Abstract Retinoic acid is regarded as the retinol metabolite that controls proliferation and differentiation of epithelial cells. In the present study, we investigated the potential role of xanthine dehydrogenase (XDH) in retinoic acid biosynthesis in human thyroid glandular cells (HTGC). In particular, we observed that cellular retinoids binding proteins (CRBPs) are also implicated in the biosynthetic pathway leading to retinoic acid formation in primary cultures of HTGC, as we have already reported for human mammary epithelial cells (HMEC). After partial protein purification, the enzyme responsible for retinoic acid biosynthesis was identified and quantified as XDH by immunoassay, by its …
Oxidative stress in marathon runners: interest of antioxidant supplementation
2006
We have recently reported that xanthine oxidase is involved in the generation of free radicals in exhaustive exercise. Allopurinol, an inhibitor of xanthine oxidase, prevents it. The aim of the present work was to elucidate the role of exercise-derived reactive oxygen species in the cell signalling pathways involved in the adaptation to exercise in man. We have found that exercise causes an increase in the activity of plasma xanthine oxidase and an activation of NF-κB in peripheral blood lymphocytes after marathon running. This activation is dependent on free radical formation in exercise: treatment with allopurinol completely prevents it. In animal models, we previously showed that NF-κB a…
Increased oxidative stress levels and normal antioxidant enzyme activity in circulating mononuclear cells from patients of familial hypercholesterole…
2010
Familial hypercholesterolemia (FH) is a clinical condition with high risk for developing atherosclerosis. Increased oxidative stress (OS) and FH have been related to atherosclerosis, but no data are available on levels of OS and antioxidant enzyme activity in circulating mononuclear cells (CMCs) from FH patients. Circulating mononuclear cells are important mediators in atherosclerosis development, and chronically increased blood OS present in FH can induce modification in CMC activity. The objective of the study was to analyze the OS levels in CMCs from FH patients and controls. We have selected 30 nonrelated FH index patients and 30 normoglycemic and normocholesterolemic controls matched b…
Increased plasma xanthine oxidase activity is related to nuclear factor kappa beta activation and inflammatory markers in familial combined hyperlipi…
2010
Abstract Background and aims Xanthine oxidase (XO) has been described as one of the major enzymes producing free radicals in blood. Oxidative stress and inflammatory processes have been implicated in the pathogenesis of endothelial dysfunction and the progression of atherosclerosis but until now, there is little data about the influence of vascular prooxidant systems and inflammation in familial combined hyperlipidemia (FCH). Our goal was to evaluate whether XO activity was altered in FCH and if it was related to the inflammatory process represented by NFkB, IL-6 and hsCRP, and assessing the correlation between XO activity and insulin resistance (IR). Method and results 40 Non-related subje…
Extreme duration exercise affects old and younger men differently.
2022
Aim & Methods: Extreme endurance exercise provides a valuable research model for understanding the adaptive metabolic response of older and younger individuals to intense physical activity. Here, we compare a wide range of metabolic and physiologic parameters in two cohorts of seven trained men, age 30 ± 5 years or age 65 ± 6 years, before and after the participants travelled ≈3000 km by bicycle over 15 days. Results: Over the 15-day exercise intervention, participants lost 2–3 kg fat mass with no significant change in body weight. V̇O2max did not change in younger cyclists, but decreased (p = 0.06) in the older cohort. The resting plasma FFA concentration decreased markedly in both gro…
Y chromosome microdeletions, sperm DNA fragmentation and sperm oxidative stress as causes of recurrent spontaneous abortion of unknown etiology.
2010
Background The aim of the present study was to evaluate the implication of male factor, in terms of sperm DNA oxidation and fragmentation, and Y chromosome microdeletions in recurrent spontaneous abortion (RSA) of unknown origin in a strictly selected cohort. Methods A prospective cohort study was carried out in a private university-affiliated setting. Three groups, each comprised of 30 males, were compared. The first was formed by healthy and fertile sperm donors (SD) with normal sperm parameters (control group), the second by men presenting severe oligozoospermia (SO) without RSA history, and the third by men from couples who had experienced idiopathic RSA. Frequency of Y chromosome micro…
Protein oxidation in mild essential hypertension
2012
An intensified oxidative stress has been associated with aging and many disease, including essential hypertension (EH) [6, 11, 16]. In EH an increased level of reactive oxygen and nitrogen species (RONS) may impair the bioavailability of nitric oxide (NO), by inducing its accelerated transformation in peroxynitrite [4]. Beside this, many other pathophysiological processes in EH may be influenced by RONS, considering their harmful effects on the structural and functional properties of lipids, proteins and nucleic acids. Some points need to be further investigated, such as the relationship between oxidative stress and the degree of hypertension, and identification of the most useful marker of…
Enhanced oxidative susceptibility and reduced antioxidant content of metabolic precursors of small, dense low-density lipoproteins.
2001
Abstract PURPOSE: Elevated plasma concentrations of low-density lipoproteins (LDL) increase risk for coronary heart disease. However, lipoprotein profiles rich in small, dense LDL particles confer greater risk than those that mainly consist of large, buoyant LDL. This may be due, in part, to the greater oxidative susceptibility of small, dense LDL. In the current studies, we tested whether differences in the oxidative behavior of buoyant and dense LDL arise from differences in their immediate metabolic precursors, intermediate-density lipoproteins. SUBJECTS AND METHODS: We compared the properties of intermediate-density lipoproteins and buoyant and dense LDL subfractions in 9 subjects with …
Nitric oxide metabolites and oxidative stress in mild essential hypertension
2010
Many papers have showed non univocal data about oxidative stress status and nitric oxide metabolites in essential hypertension. Considering this preamble we examined the total antioxidant status (TAS), the lipid peroxidation (LP), expressed as thiobarbituric acid-reactive substances (TBARS), the stable end products of nitric oxide (NOx) and LP/NOx ratio in 25 subjects with untreated mild essential hypertension. The obtained data show a significant increase in TBARS (p < 0.001) and NOx (p < 0.001) in hypertensives and no variation in TAS and in TBARS/NOx ratio. None of these parameters was statistically related to the metabolic parameters or to the blood pressure values. The high level of li…
Lipid peroxidation and nitric oxide metabolites in sedentary subjects and sportsmen before and after a cardiopulmonary test.
2012
Our aim was to investigate the effects of an exercise test on some indices of oxidative status and endothelial function, in trained and untrained subjects. We examined lipid peroxidation, nitric oxide metabolites (NOx) and their ratio before and after a cardiopulmonary test, using a cycloergometer. We enrolled 60 male subjects who practiced sport unprofessionally, subdivided in two groups (A and B) according to the values of VO2max. Group A included sportsmen with poor or fair aerobic fitness (VO2max 39 ml/Kg/min). The control group included 19 male sedentary subjects. Lipid peroxidation was evaluated by detection of the thiobarbituric acid-reactive substances (TBARS); the NOx were evaluate…