Hepatic oxidative stress in an animal model of sleep apnoea: effects of different duration of exposure

Background: Repeated apnoea events cause intermittent hypoxia (IH), which alters the function of various systems and produces free radicals and oxidative stress. Methods: We investigated hepatic oxidative stress in adult mice subjected to intermittent hypoxia, simulating sleep apnoea. Three groups were submitted to 21 days of IH (IH-21), 35 days of IH (IH-35), or 35 days of sham IH. We assessed the oxidative damage to lipids by TBARS and to DNA by comet assay; hepatic tissue inflammation was assessed in HE-stained slides. Antioxidants were gauged by catalase, superoxide dismutase, glutathione peroxidase activity and by total glutathione. Results: After IH-21, no significant change was observed in hepatic oxidative stress. After IH-35, significant oxidative stress, lipid peroxidation, DNA damage and reduction of endogenous antioxidants were detected. Conclusions: In an animal model of sleep apnoea, intermittent hypoxia causes liver damage due to oxidative stress after 35 days, but not after 21 days

THE EFFECT OF INTERMITTENT HYPOXIC TRAINING UNDER OXIDATIVE STRESS PARAMETERS IN WISTAR RATS FED ON STANDARD AND HIGH FAT DIET

Considerando-se que dietas ricas em gordura levam ao estresse oxidativo, causando lesões nas células e que o treinamento hipóxico intermitente (THI) aumenta as defesas antioxidantes endógenas em diversas situações, o objetivo deste estudo foi avaliar o efeito do THI em parâmetros de estresse oxidativo e defesas antioxidantes em fígado de ratos Wistar alimentados com dieta rica em gordura e/ou dieta padrão. Ratos Wistar foram divididos em grupos alimentados com dieta padrão ou rica em gordura. Os grupos foram submetidos a hipóxia intermitente (HI), 15 minutos HI (14-11% O2) intercalados com cinco minutos de re-oxigenação ou sessões de normóxia (N) (21% O2), por um período de duas horas diárias durante 30 dias. Os ratos Wistar alimentados com dieta padrão, e submetidas a HI, apresentaram uma redução de 37,7% na concentração de substâncias reativas ao ácido tiobarbitúrico (TBARS) e aumento de 34,66% e 39,8% no conteúdo de superóxido dismutase (SOD) e catalase (CAT), respectivamente, em comparação com o seu controlo (normoxia). No grupo com dieta rica em gordura, não houve diferença estatística entre os subgrupos HI e N. Nossos dados, que demonstram que o THI possui efeito antioxidante no fígado de ratos Wistar, argumentam em favor do uso alternativo de protocolos de hipoxia intermitente no tratamento de determinadas patologias

Redox profile in liver of Leporinus macrocephalus exposed to different dissolved oxygen levels

Aquatic organisms are continuously exposed to environmental variations, which can lead to physiological and biochemical alterations. Leporinus macrocephalus, known as piavuçu, is a migratory species that may be exposed to variations in dissolved oxygen levels. Studies evaluating oxidative changes undergone by this species in these conditions are scarce. Therefore, this investigation aimed at evaluating oxidative alterations in L. macrocephalus exposed to different oxygen levels for 96 h: 6. 12 ± 0. 18, 3. 99 ± 0. 17, 3. 22 ± 0. 17, 2. 47 ± 0. 30 and 0. 710 ± 0. 07 mg L -1. At the end of the experimental period, fish were euthanized and livers used to determine lipid hydroperoxides, thiobarbituric acid reactive substances, catalase, glutathione-S-transferase, superoxide dismutase and thiol groups, which are an indirect measure of reduced glutathione. Results indicated a decrease in the studied parameters in hypoxic situations, suggesting a possible metabolic depression. © 2011 Springer Science+Business Media B.V.Fil: Riffel, A. P. K.. Universidade Federal de Santa Maria; BrasilFil: Garcia, L. O.. Universidade Federal de Santa Maria; Brasil. Universidade Federal do Rio Grande do Norte; BrasilFil: Finamor, I. A.. Universidade Federal de Santa Maria; BrasilFil: Saccol, E.M.H.. Universidade Federal de Santa Maria; BrasilFil: Meira, M.. Universidade Federal de Santa Maria; BrasilFil: Kolberg, C.. Universidade Federal do Rio Grande do Sul; BrasilFil: Horst, A.. Universidade Federal do Rio Grande do Sul; BrasilFil: Partata, W.. Universidade Federal do Rio Grande do Sul; BrasilFil: Llesuy, Susana Francisca. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Baldisserotto, B.. Universidade Federal de Santa Maria; BrasilFil: Pavanato, M. A.. Universidade Federal de Santa Maria; Brasi

Azathioprine monotherapy withdrawal in inflammatory bowel diseases: A retrospective mono-centric study

Background: There is no consensus on the recommended duration of and optimal time to stop azathioprine (AZA) therapy in inflammatory bowel disease (IBD). Determining the optimal duration and cessation time can help to balance the risks of long-term intake with the possibility of relapse after cessation. Aim: To describe the events following AZA cessation. Methods: Retrospective analysis was performed to examine data from adult patients affected by IBD who were followed at the University of Padua and had started but then discontinued AZA between 1995 and 2022. Data on therapy duration, reasons for cessation, and type of relapse after cessation were collected. Cox regression models were used to estimate the risk of relapse in different subgroups. Results: A total of 133 ulcerative colitis patients and 141 Crohn's disease patients were included. Therapy with AZA was stopped in the 1st year in approximately 34% of patients but was continued for more than 10 years in approximately 10% of cases. AZA discontinuation was due to primary failure or disease relapse in 30% of patients and due to disease remission in 25.2% of patients. Most of the remaining cases stopped AZA therapy due to side effects (primarily clinical intolerance, cytopenia, and pancreatic disease). Patients who stopped AZA for clinical remission had an 83% lower risk of relapse during the observation time than other groups, with a relapse-free rate of 89% after 1 year and 79% after 2 years. Conclusion: AZA administration is effective and safe, but it requires careful monitoring for potential minor and major side effects. Only 10% of patients who achieved remission with AZA needed a new treatment within 1 year of drug interruption

T2-weighted BOLD in human myocardium

The principal aim of this work is to test the viability of Blood Oxygenation Level Dependent (BOLD) measurements in human myocardium, an experiment which has seen promising attempts in recent literature. A central challenge to the ~uccess of these experiments has been in the limited scale of the measured effect; this work therefore includes efforts to separate the BOLD effect from noise and confounding signals. BOLD is then measured by intensity in MR images produced using Steady State Free Precession (SSFP) acquisition, weighted by a T2 preparation module to introduce the target contrast. Two modelling sections are included: first, the changes in physiology which influence the signal intensity in the MR images via the T2 dependence; and secondly the factors upon which the preparation depends, which are not entirely limited to the T2 of the tissue. These models are investigated with the aim of increasing the BOLD contrast and removing any other dependencies. An empirical model is shown to be suitable for the relationship between oxygenation and T2, and improvements are suggested and explained by thorough simulation ofthe preparation module. Compensation for a further confounding effect is also investigated: that of the increase in heart rate which accompanies the adenosine infusion used in the BOLD experiment protocol to reveal differences in the response of ischaemic and healthy tissue. The compensation is shown to reduce temporal variance in SI measurements, and to increase the separation between distributions of SI in tissue classes. A process of registration and segmentation is refined for sampling BOLD information from the SS FP images, and tested to show a low failure rate. Finally, the BOLD process is then tested in a set of human subjects including healthy volunteers and patients with coronary artery disease, investigating the consequent difference in tissue oxygenation. A significant difference is shown in the responses to stress of BOLD SI three tissue classes in these subjects.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

La correspondencia de Valencia : diario de noticias : eco imparcial de la opinión y de la prensa: Año XLI Número 17420 - 1918 Mayo 05

Copia digital. Madrid : Ministerio de Cultura. Subdirección General de Coordinación Bibliotecaria, 200