997 resultados para Oxidative variables


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BACKGROUND Renal ischemia/reperfusion (I/R) injury is manifested by acute renal failure (ARF) and acute tubular necrosis (ATN). The aim of this study was to evaluate the effectiveness of preconditioning with 3, 3, 5 triiodothyronine (T3) to prevent I/R renal injury. METHODOLOGY/PRINCIPAL FINDINGS THE RATS WERE DIVIDED INTO FOUR GROUPS: sham-operated, placebo-treated (SO-P), sham-operated T3- treated (SO- T3), I/R-injured placebo-treated (IR-P), and I/R-injured T3-treated (IR- T3) groups. At 24 h before ischemia, the animals received a single dose of T3 (100 μg/kg). Renal function and plasma, urinary, and tissue variables were studied at 4, 24, and 48 h of reperfusion, including biochemical, oxidative stress, and inflammation variables, PARP-1 immunohistochemical expression, and ATN morphology. In comparison to the SO groups, the IR-P groups had higher plasma urea and creatinine levels and greater proteinuria (at all reperfusion times) and also showed: increased oxidative stress-related plasma, urinary, and tissue variables; higher plasma levels of IL6 (proinflammatory cytokine); increased glomerular and tubular nuclear PARP-1 expression; and a greater degree of ATN. The IR-T3 group showed a marked reduction in all of these variables, especially at 48 h of reperfusion. No significant differences were observed between SO-P and SO-T3 groups. CONCLUSIONS This study demonstrates that preconditioning rats with a single dose of T3 improves the clinical signs and ATN of renal I/R injury. These beneficial effects are accompanied by reductions in oxidative stress, inflammation, and renal PARP-1 expression, indicating that this sequence of factors plays an important role in the ATN induced by I/R injury.

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Aquest treball s’ha realitzat en el Centre Educatiu Montilivi, un centre de Justícia Juvenil, on predominen les mesures en règim semiobert. L’objectiu principal del centre és oferir als menors la experiència i la formació necessària per superar els handicaps, deixar l’activitat delictiva i participar en la societat de manera normalitzada. L’any 2002 es va implantar un sistema motivacional que, basat en el condicionament operant i l’aprenentatge social, facilités la participació activa i responsable dels interns. El sistema motivacional s’estructura en etapes progressives. El menor, superat el període d’observació inicial, se l’assigna a una etapa on pot gaudir dels avantatges corresponents. Una avaluació continuada, li permetrà anar assolint la puntuació necessària que li donarà la opció de progressar a una etapa superior. En aquesta gaudirà de més avantatges. L’objectiu bàsic de la recerca és avaluar l’eficàcia del sistema motivacional pel que fa la desaparició o reducció de les conductes indesitjables de: no retorn, fugides, reincidència i conflictes dins del centre i buscar relació d’aquestes variables amb diversos factors individuals. Per dur a terme la recerca s’han seleccionat 135 menors que hem distribuït en dos grups. un grup de control anterior a la implementació del sistema motivacional; i un grup d’intervenció a qui si se’ls ha aplicat el sistema motivacional. Els resultats diuen que la mostra respon a un patró antisocial greu. També diu que l’aplicació d’un sistema motivacional no s’ha associat a una reducció de les conductes antisocials dels interns durant el període d’aplicació. Malgrat això, sí es percebut com una eina eficaç per interns i professionals.

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INTRODUCTION Selenium is an essential micronutrient for human health, being a cofactor for enzymes with antioxidant activity that protect the organism from oxidative damage. An inadequate intake of this mineral has been associated with the onset and progression of chronic diseases such as hypertension, diabetes, coronary diseases, asthma, and cancer. For this reason, knowledge of the plasma and erythrocyte selenium levels of a population makes a relevant contribution to assessment of its nutritional status. OBJECTIVE The objective of the present study was to determine the nutritional status of selenium and risk of selenium deficiency in a healthy adult population in Spain by examining food and nutrient intake and analyzing biochemical parameters related to selenium metabolism, including plasma and erythrocyte levels and selenium-dependent glutathione peroxidase (GPx) enzymatic activity. MATERIAL AND METHODS We studied 84 healthy adults (31 males and 53 females) from the province of Granada, determining their plasma and erythrocyte selenium concentrations and the association of these levels with the enzymatic activity of glutathione peroxidase (GPx) and with life style factors. We also gathered data on their food and nutrient intake and the results of biochemical analyses. Correlations were studied among all of these variables. RESULTS The mean plasma selenium concentration was 76.6 ± 17.3 μg/L (87.3 ± 17.4 μg/L in males, 67.3 ± 10.7 μg/L in females), whereas the mean erythrocyte selenium concentration was 104.6 μg/L (107.9 ± 26.1 μg/L in males and 101.7 ± 21.7 μg/L in females). The nutritional status of selenium was defined by the plasma concentration required to reach maximum GPx activity, establishing 90 μg/L as reference value. According to this criterion, 50% of the men and 53% of the women were selenium deficient. CONCLUSIONS Selenium is subjected to multiple regulation mechanisms. Erythrocyte selenium is a good marker of longer term selenium status, while plasma selenium appears to be a marker of short-term nutritional status. The present findings indicate a positive correlation between plasma selenium concentration and the practice of physical activity. Bioavailability studies are required to establish appropriate reference levels of this mineral for the Spanish population.

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Aproximadament un 40% dels subjectes de la mostra de 1.14a subjectes no han arribat a ser considerats per a l’alliberament condicional, tot i haver complert les 3/4 parts de la condemna. La modalitat de llibertat condicional ordinària en complir les ¾ parts de la condemna predomina sobre la resta de modalitats d’alliberament. En el cas d’aquest estudi, només un 7,6% havia accedit al benefici de la llibertat condicional avançada. Respecte a la incidència de les variables personals en l’accés a la llibertat condicional, ser dona, tenir nacionalitat espanyola i un nivell molt baix o un nivell alt de formació influeix positivament en l’obtenció de la llibertat condicional. La variable nacionalitat estrangera té una influència molt negativa en la concessió de la llibertat condicional. Respecte a les variables penals, els delictes de lesions, seguits dels delictes contra la propietat, com tots els tipus de robatoris, tenen els percentatges de denegació de la llibertat condicional més alts. Respecte a les variables penitenciàries, es conclou que com més obert sigui el règim inicialment aplicat, més probabilitats hi ha de sortir en llibertat condicional. Les activitats realitzades durant el compliment de la condemna no semblen tenir, en general, una incidència positiva en la concessió de la llibertat condicional. En aquest sentit, es podria dir que ja a l’inici de la condemna es pot determinar les possibilitats que es tindran de sortir en llibertat condicional, independentment dels progressos o canvis que es realitzin durant el compliment de la condemna. Les variables més significatives en la concessió de la llibertat condicional, segons l’anàlisi de regressió logística, són 4: l’habitualitat, els dies totals de sortida en funció del temps, el temps passat com a preventiu i el nombre de faltes greus. La regressió logística ha permès construir una equació amb aquestes 4 variables independents, que dibuixa el perfil d’un intern en llibertat condicional, i també descriu quins són els interns susceptibles de gaudir de la llibertat condicional o no, amb la probabilitat d’encertar en 80 de cada 100 casos.

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The Firmicutes bacteria participate extensively in virulence and pathological processes. Enterococcus faecalis is a commensal microorganism; however, it is also a pathogenic bacterium mainly associated with nosocomial infections in immunocompromised patients. Iron-sulfur [Fe-S] clusters are inorganic prosthetic groups involved in diverse biological processes, whose in vivo formation requires several specific protein machineries. Escherichia coli is one of the most frequently studied microorganisms regarding [Fe-S] cluster biogenesis and encodes the iron-sulfur cluster and sulfur assimilation systems. In Firmicutes species, a unique operon composed of the sufCDSUB genes is responsible for [Fe-S] cluster biogenesis. The aim of this study was to investigate the potential of the E. faecalis sufCDSUB system in the [Fe-S] cluster assembly using oxidative stress and iron depletion as adverse growth conditions. Quantitative real-time polymerase chain reaction demonstrated, for the first time, that Gram-positive bacteria possess an OxyR component responsive to oxidative stress conditions, as fully described for E. coli models. Likewise, strong expression of the sufCDSUB genes was observed in low concentrations of hydrogen peroxide, indicating that the lowest concentration of oxygen free radicals inside cells, known to be highly damaging to [Fe-S] clusters, is sufficient to trigger the transcriptional machinery for prompt replacement of [Fe-S] clusters.

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Landscape is an example of a non-market good where no metrics exist to measure its quality. The paper proposes an original methodology to nevertheless estimate scope variables in those circumstances, allowing then to better test if people's willingnesstopay for such good is sensitive to the scope. The methodology is based on techniques developed in the context of multicriteria decision analysis. It is applied to assess the quality of the landscape of several Swiss alpine resorts. This assessment is then used as an explanatory variable in a hedonic price function to explain the rent of apartments and to derive an implicit price of the landscape quality.

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In the last few years, many researchers have studied the presence of common dimensions of temperament in subjects with symptoms of anxiety. The aim of this study is to examine the association between temperamental dimensions (high negative affect and activity level) and anxiety problems in clinicalpreschool children. A total of 38 children, ages 3 to 6 years, from the Infant and Adolescent Mental Health Center of Girona and the Center of Diagnosis and Early Attention of Sabadell and Olot were evaluated by parents and psychologists. Their parents completed several screening scales and, subsequently, clinical child psychopathology professionals carried out diagnostic interviews with children from the sample who presented signs of anxiety. Findings showed that children with high levels of negative affect and low activity level have pronounced symptoms of anxiety. However, children with anxiety disorders do not present different temperament styles from their peers without these pathologies

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Malnutrition affects 40-50% of patients with ear, nose and throat (ENT) cancer. The aim of this study was to assess changes induced by a specific nutritional supplement enriched with n-3 polyunsaturated fatty acids, fiber and greater amounts of proteins and electrolytes, as compared with a standard nutritional supplement, on markers of inflammation, oxidative stress and metabolic status of ENT cancer patients undergoing radiotherapy (RT). Fourteen days after starting RT, 26 patients were randomly allocated to one of two groups, 13 supplemented with Prosure, an oncologic formula enriched with n-3 polyunsaturated fatty acids, fiber and greater amounts of proteins and electrolytes (specific supplement), and 13 supplemented with Standard-Isosource (standard supplement). Patients were evaluated before RT, and 14, 28 and 90 days after starting RT. The results showed that there were no significant differences between the groups, but greater changes were observed in the standard supplement group, such as a decline in body mass index (BMI), reductions in hematocrit, erythrocyte, eosinophil and albumin levels, and a rise in creatinine and urea levels. We concluded that metabolic, inflammatory and oxidative stress parameters were altered during RT, and began to normalize at the end of the study. Patients supplemented with Prosure showed an earlier normalization of these parameters, with more favorable changes in oxidative stress markers and a more balanced evolution, although the difference was not significant.

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BACKGROUND & AIMS: Nutrition and dietary patterns have been shown to have direct impact on health of the population and of selected patient groups. The beneficial effects have been attributed to the reduction of oxidative damage caused by the normal or excessive free radical production. The papers aims at collecting evidence of successful supplementation strategies. METHODS: Review of the literature reporting on antioxidant supplementation trials in the general population and critically ill patients. RESULTS: Antioxidant vitamin and trace element intakes have been shown to be particularly important in the prevention of cancer, cardiovascular diseases, age related ocular diseases and in aging. In animal models, targeted interventions have been associated with reduction of tissue destruction is brain and myocardium ischemia-reperfusion models. In the critically ill antioxidant supplements have resulted in reduction of organ failure and of infectious complications. CONCLUSIONS: Antioxidant micronutrients have beneficial effects in defined models and pathologies, in the general population and in critical illness: ongoing research encourages this supportive therapeutic approach. Further research is required to determined the optimal micronutrient combinations and the doses required according to timing of intervention.

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AIMS/HYPOTHESIS: Pro-atherogenic and pro-oxidant, oxidised LDL trigger adverse effects on pancreatic beta cells, possibly contributing to diabetes progression. Because oxidised LDL diminish the expression of genes regulated by the inducible cAMP early repressor (ICER), we investigated the involvement of this transcription factor and of oxidative stress in beta cell failure elicited by oxidised LDL. METHODS: Isolated human and rat islets, and insulin-secreting cells were cultured with human native or oxidised LDL or with hydrogen peroxide. The expression of genes was determined by quantitative real-time PCR and western blotting. Insulin secretion was monitored by EIA kit. Cell apoptosis was determined by scoring cells displaying pycnotic nuclei. RESULTS: Exposure of beta cell lines and islets to oxidised LDL, but not to native LDL raised the abundance of ICER. Induction of this repressor by the modified LDL compromised the expression of important beta cell genes, including insulin and anti-apoptotic islet brain 1, as well as of genes coding for key components of the secretory machinery. This led to hampering of insulin production and secretion, and of cell survival. Silencing of this transcription factor by RNA interference restored the expression of its target genes and alleviated beta cell dysfunction and death triggered by oxidised LDL. Induction of ICER was stimulated by oxidative stress, whereas antioxidant treatment with N-acetylcysteine or HDL prevented the rise of ICER elicited by oxidised LDL and restored beta cell functions. CONCLUSIONS/INTERPRETATION: Induction of ICER links oxidative stress to beta cell failure caused by oxidised LDL and can be effectively abrogated by antioxidant treatment.

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Oxidative stress occurs when the production of reactive oxygen species (ROS) by an organism exceeds its capacity to mitigate the damaging effects of the ROS. Consequently, oxidative stress hypotheses of ageing argue that a decline in fecundity and an increase in the likelihood of death with advancing age reported at the organism level are driven by gradual disruption of the oxidative balance at the cellular level. Here, we measured erythrocyte resistance to oxidative stress in the same individuals over several years in two free-living bird species with contrasting life expectancy, the great tit (known maximum life expectancy is 15.4 years) and the Alpine swift (26 years). In both species, we found evidence for senescence in cell resistance to oxidative stress, with patterns of senescence becoming apparent as subjects get older. In the Alpine swift, there was also evidence for positive selection on cell resistance to oxidative stress, the more resistant subjects being longer lived. The present findings of inter-individual selection and intra-individual deterioration in cell oxidative status at old age in free-living animals support a role for oxidative stress in the ageing of wild animals.