Search results for "OXIDASE"
showing 10 items of 927 documents
Mechanism of Free Radical Production in Exhaustive Exercise in Humans and Rats; Role of Xanthine Oxidase and Protection by Allopurinol
2000
Exhaustive exercise generates free radicals, However, the source of this oxidative damage remains controversial. The aim of this paper was to study further the mechanism of exercise-induced production of free radicals, Testing the hypothesis that xanthine oxidase contributes to the production of free radicals during exercise, me found not only that exercise caused an increase in blood xanthine oxidase activity in rats but also that inhibiting xanthine oxidase with allopurinol prevented exercise-induced oxidation of glutathione in both rats and in humans. Furthermore, inhibiting xanthine oxidase prevented the increases in the plasma activity of cytosolic enzymes (lactate dehydrogenase, aspar…
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…
Congenital goitrous primary hypothyroidism in two German families caused by novel thyroid peroxidase (TPO) gene mutations.
2013
Congenital hypothyroidism occurs with a prevalence of approximately 1:3 500. Defects in thyroid hormone synthesis which lead to goitrous hypothyroidism account for 10-15% of these cases. Several genetic defects have been characterized and mutations in the thyroid peroxidase (TPO) gene are the most common cause for dyshormonogenesis.So far, more than 80 mutations in the TPO gene have been described, resulting in a variable decrease in TPO bioactivity. Clinically TPO defects manifest with congenital primary goitrous hypothyroidism.We here present 2 children with congenital primary hypothyroidism, who were identified to have compound heterozygous TPO mutations. They both shared the same novel …
Prospective study on thyroid autoimmunity and dysfunction related to chronic hepatitis C and interferon therapy.
1997
This study was designed to assess patients with chronic hepatitis C (CHC) for the presence of thyroid autoimmunity and dysfunction, to evaluate the risk of thyroid disorders associated with interferon (IFN) therapy, and to survey the outcome of possible treatment-related thyroid injury. Out of 104 consecutive untreated patients (30 women and 74 men; mean age, 52.7 years), 8 (7.7%) were found seropositive for thyroid autoantibodies (ThyAb), whereas seropositivity in healthy controls was 1/98 (1.3%). The relative increase in risk of developing thyroid autoimmunity associated with CHC was 760% (95% Cl, 220–1300%). No patients had abnormalities of thyroid function tests, but on IFN treatment, 3…
Diagnostic and prognostic performance of myeloperoxidase plasma levels compared with sensitive troponins in patients admitted with acute onset chest …
2012
Background— Activation of leukocytes with release of myeloperoxidase (MPO) has been linked to acute coronary disease. To date, studies investigating the diagnostic and prognostic performance of circulating MPO in patients with chest pain (CP) are mainly retrospective, of low size, and lack a cut-off value for MPO. Herein, we prospectively assess the diagnostic and prognostic properties of MPO compared with sensitive troponin I (sTNI) in patients admitted to the emergency room with CP. Methods and Results— One thousand, eight hundred and eighteen consecutive patients (mean age, 61.4±13.5 years; 33.6% female) admitted for CP underwent determination of MPO, sTnI, and B-natriuretic peptide pla…
Effects of the association of aging and obesity on lipids, lipoproteins and oxidative stress biomarkers: a comparison of older with young men.
2011
In this study, plasma lipids, lipoproteins and markers of oxidant/antioxidant status were investigated in young (n = 45) and older (n = 40) obese men and compared to those in young (n = 65) and older (n = 55) normal weight controls. The purpose was to determine whether obesity exacerbates or not lipid, lipoprotein abnormalities and oxidative stress in older men. Our findings showed that all obese patients had increased plasma triglyceride, cholesterol, LDL-cholesterol, -triglyceride and HDL-triglyceride levels concentrations compared to controls (P < 0.01). However, the younger obese men had relatively larger and accentuated changes in plasma lipids and lipoproteins than the older patients.…
Age-dependent decline of steady state dopamine storage capacity of human brain: an FDOPA PET study.
2010
Conventional indices of the utilization of FDOPA in living human brain have not consistently revealed important declines in dopamine function with normal aging. However, most methods of kinetic analysis have assumed irreversible trapping of decarboxylated FDOPA metabolites in brain, an assumption that is violated even in PET recordings of short duration. Therefore, we have developed methods for the calculation of steady-state storage of FDOPA together with its decarboxylated metabolites (V(d), mlg(-1)), based upon improved kinetic analysis of 120-min emission recordings. In a group of 28 normal male subjects, of age ranging from 23 to 73 years, the magnitude of V(d) in the striatum and in e…
Age-related increase in xanthine oxidase activity in human plasma and rat tissues.
2007
This study assessed the role of xanthine oxidase in vascular ageing. A positive correlation between xanthine oxidase activity and age was found in human plasma. Similar results were found in rat plasma. Xanthine oxidase expression and activity in homogenates from the aortic wall were significantly higher in samples from old rats than in their young counterparts (p<0.01). In rat skeletal muscle homogenates both xanthine oxidase expression and activity showed a similar age-related profile. Superoxide production by xanthine oxidase in aortic rings was higher in aged rats. Uric acid, the final product of xanthine oxidase has been proposed as a risk factor for coronary heart disease and an indep…