Search results for "DPH"
showing 10 items of 361 documents
Energetic coupling between plastids and mitochondria drives CO2 assimilation in diatoms.
2015
International audience; Diatoms are one of the most ecologically successful classes of photosynthetic marine eukaryotes in the contemporary oceans. Over the past 30 million years, they have helped to moderate Earth's climate by absorbing carbon dioxide from the atmosphere, sequestering it via the biological carbon pump and ultimately burying organic carbon in the lithosphere. The proportion of planetary primary production by diatoms in the modern oceans is roughly equivalent to that of terrestrial rainforests. In photosynthesis, the efficient conversion of carbon dioxide into organic matter requires a tight control of the ATP/NADPH ratio which, in other photosynthetic organisms, relies prin…
On the feasibility of personal audio systems over a network of distributed loudspeakers
2018
Los sistemas de reproducción de audio personal se ocupan de la creación de zonas sonoras personales dentro de una habitación sin necesidad de utilizar auriculares. Estos sistemas utilizan un conjunto de altavoces y diseñan los filtros necesarios en cada altavoz con el fin de que la señal de audio deseada llegue a cada persona en la sala lo más libre de interferencias posible. Existen propuestas muy interesantes en la literatura que hacen uso de arrays circulares o lineales, pero en este trabajo estudiamos el problema considerando una red de altavoces distribuidos controlados por un conjunto de nodos acústicos, que pueden intercambiar información a través de una red. Enunciamos el modelo de …
MTHFR 677C → T genotype modulates the effect of a 5-year supplementation with B-vitamins on homocysteine concentration: The SU.FOL.OM3 randomized con…
2018
Aims To study how MTHFR 677C→T genotype modulates the effect of supplementation with B-vitamins on total homocysteine (tHcy) and B-vitamin concentrations. Methods 2381 patients with a personal history of cardiovascular disease were randomly assigned to one of four groups: 1) B-vitamins alone (560 μg of 5-methyl-THF, 3 mg of vitamin B6 and 20 μg of vitamin B12), 2) n-3 fatty acids alone (600 mg of EPA and DHA in a 2:1 ratio), 3) B-vitamins and n-3 fatty acids, and 4) placebo. Participants were followed up for 4.7 years. At baseline and annually thereafter, biological parameters were assessed. Multivariate and linear mixed models were fit to study the interaction between B-vitamins and MTHFR …
Short-term e-cigarette vapour exposure causes vascular oxidative stress and dysfunction: evidence for a close connection to brain damage and a key ro…
2019
Abstract Aims Electronic (e)-cigarettes have been marketed as a ‘healthy’ alternative to traditional combustible cigarettes and as an effective method of smoking cessation. There are, however, a paucity of data to support these claims. In fact, e-cigarettes are implicated in endothelial dysfunction and oxidative stress in the vasculature and the lungs. The mechanisms underlying these side effects remain unclear. Here, we investigated the effects of e-cigarette vapour on vascular function in smokers and experimental animals to determine the underlying mechanisms. Methods and results Acute e-cigarette smoking produced a marked impairment of endothelial function in chronic smokers determined b…
New evidence for the multiplicity of ubiquinone- and inhibitor-binding sites in the mitochondrial complex I.
2000
Determination of the number of ubiquinone- and inhibitor-binding sites in the mitochondrial complex I (NADH:ubiquinone oxidoreductase) is a controversial question with a direct implication for elaborating a suitable model to explain the bioenergetic mechanism of this complicated enzyme. We have used combinations of both selective inhibitors and common ubiquinone-like substrates to demonstrate the multiplicity of the reaction centers in the complex I in contrast with competition studies that have suggested the existence of a unique binding site for ubiquinone. Our results provide new evidence for the existence of at least two freely exchangeable ubiquinone-binding sites with different specif…
Hypothalamic reactive oxygen species are required for insulin-induced food intake inhibition: an NADPH oxidase-dependent mechanism
2009
1939-327X (Electronic) Journal Article Research Support, Non-U.S. Gov't; OBJECTIVE: Insulin plays an important role in the hypothalamic control of energy balance, especially by reducing food intake. Emerging data point to a pivotal role of reactive oxygen species (ROS) in energy homeostasis regulation, but their involvement in the anorexigenic effect of insulin is unknown. Furthermore, ROS signal derived from NADPH oxidase activation is required for physiological insulin effects in peripheral cells. In this study, we investigated the involvement of hypothalamic ROS and NADPH oxidase in the feeding behavior regulation by insulin. RESEARCH DESIGN AND METHODS: We first measured hypothalamic RO…
Time course of asymmetric dimethylarginine (ADMA) and oxidative stress in fructose-hypertensive rats: A model related to metabolic syndrome
2011
Asymmetric dimethylarginine (ADMA) is an endogenous modulator of endothelial function and oxidative stress, and increased levels of this molecule have been reported in some metabolic disorders and cardiovascular diseases. The aim of this work was to analyze the time course of dimethylarginine compounds and oxidative stress levels and the relationship between these and cardiovascular function in fructose-hypertensive rats.90 male Sprague-Dawley rats were randomized into 2 groups, fed for 3 months with standard (C) chow supplemented or not with fructose (F, 60%). After sacrifice at different weeks (W), the aorta and plasma were harvested to assess the vascular and biochemical parameters. Our …
Vascular Dysfunction in Streptozotocin-Induced Experimental Diabetes Strictly Depends on Insulin Deficiency
2010
<i>Objective:</i> In previous studies we and others have shown that streptozotocin (STZ)-induced diabetes in rats is associated with vascular oxidative stress and dysfunction. In the present study, we sought to determine whether vascular dysfunction and oxidative stress strictly depend on insulin deficiency. <i>Methods:</i> The effects of insulin (2.5 U/day s.c., 2 weeks) therapy on vascular disorders in STZ-induced (60 mg/kg i.v., 8 weeks) diabetes mellitus (type I) were studied in Wistar rats. The contribution of NADPH oxidase to overall oxidative stress was investigated by in vivo (30 mg/kg/day s.c., 4 days) and in vitro treatment with apocynin. <i>Results:&…
AT1-receptor blockade by telmisartan upregulates GTP-cyclohydrolase I and protects eNOS in diabetic rats.
2008
Several enzymatic sources of reactive oxygen species (ROS) were described as potential reasons of eNOS uncoupling in diabetes mellitus. In the present study, we investigated the effects of AT1-receptor blockade with chronic telmisartan (25 mg/kg/day, 6.5 weeks) therapy on expression of the BH4-synthesizing enzyme GTP-cyclohydrolase I (GCH-I), eNOS uncoupling, and endothelial dysfunction in streptozotocin (STZ, 60 mg/kg iv, 7 weeks)-induced diabetes mellitus (type I). Telmisartan therapy did not modify blood glucose and body weight. Aortas from diabetic animals had vascular dysfunction as revealed by isometric tension studies (acetylcholine and nitroglycerin potency). Vascular and cardiac RO…
Vascular Dysfunction in Experimental Diabetes Is Improved by Pentaerithrityl Tetranitrate but Not Isosorbide-5-Mononitrate Therapy
2011
OBJECTIVE Diabetes is associated with vascular oxidative stress, activation of NADPH oxidase, and uncoupling of nitric oxide (NO) synthase (endothelial NO synthase [eNOS]). Pentaerithrityl tetranitrate (PETN) is an organic nitrate with potent antioxidant properties via induction of heme oxygenase-1 (HO-1). We tested whether treatment with PETN improves vascular dysfunction in the setting of experimental diabetes. RESEARCH DESIGN AND METHODS After induction of hyperglycemia by streptozotocin (STZ) injection (60 mg/kg i.v.), PETN (15 mg/kg/day p.o.) or isosorbide-5-mononitrate (ISMN; 75 mg/kg/day p.o.) was fed to Wistar rats for 7 weeks. Oxidative stress was assessed by optical methods and o…