Search results for "Oxidation-Reduction"
showing 10 items of 689 documents
Medical significance of peroxisome proliferator-activated receptors.
1999
Peroxisome proliferator-activated receptors (PPAR) were discovered in 1990, ending 25 years of uncertainty about the molecular mechanisms of peroxisome proliferation. Subsequently, PPARs have improved our understanding of adipocyte differentiation. But there is more to PPARs than solving a puzzle about an organelle (the peroxisome) long considered an oddity, and their medical significance goes beyond obesity too. Enhanced PPAR type alpha expression protects against cardiovascular disorders though the role of enhanced PPARgamma expression seems less favourable. PPAR mechanisms, mainly via induction of more differentiated cell phenotypes, protect against some cancers. The differentiation of m…
Ghrelin reduces hepatic mitochondrial fatty acid beta oxidation.
2007
Ghrelin is a 28-amino-acid peptide secreted during starvation by gastric cells. Ghrelin physiologically induces food intake and seems to alter lipid and glucid metabolism in several tissues such as adipose tissue and liver. Liver has a key position in lipid metabolism as it allows the metabolic orientation of fatty acids between oxidation and esterification. We investigated the effects of peripheral ghrelin administration on 2 crucial parameters of fatty acid oxidation: the levocarnitine (L-carnitine)-dependent entry of the fatty acids in the mitochondria and the mitochondrial fatty acid oxidation. Ghrelin was either given to rats prior to the hepatocyte preparation and culture or used to t…
Wine consumption and renal diseases: new perspectives.
2006
Investigations into the relation between wine consumption and kidney disease have been limited. Patients with chronic renal failure show accelerated atherosclerotic damage and, considering the well-known protective effect of wine on the cardiovascular system, moderate wine consumption might be advantageous. Oxidative stress and endothelial dysfunction, which are inter-related, play a role in the pathophysiology of many renal diseases, including acute and chronic renal failure. Ethanol and non-alcoholic wine components, especially polyphenols, influence oxidative balance and endothelial function. Although long-term alcohol abuse has been associated with many renal alterations in humans, in e…
Effects of alcohol-free beer on lipid profile and parameters of oxidative stress and inflammation in elderly women
2009
We assessed the influence of alcohol-free beer on factors implicated in atherosclerosis, such as lipid profile, oxidative stress parameters, and proinflammatory cytokines, in postmenopausal women, a population particularly at risk for atherosclerotic disease.The study was carried out in 29 nuns, 58 to 73 y old, who live in a convent with a disciplined, regular, and homogeneous lifestyle. The nuns maintained their habits and diet routine, but their meals were supplemented with 500 mL/d of alcohol-free beer (0.0%) divided into two doses over a 45-d period. Lipid profile, inflammatory markers such as C-reactive protein, interleukins 1 and 6, and tumor necrosis factor-alpha, and parameters of o…
Effects of oxidative modifications induced by the glycation of bovine serum albumin on its structure and on cultured adipose cells
2005
Non-enzymatic glycosylation (glycation) and oxidative damages represent major research areas insofar as such modifications of proteins are frequently observed in numerous states of disease. Albumin undergoes structural and functional alterations, caused by increased glycosylation during non insulin-dependent diabetes mellitus, which is closely linked with the early occurrence of vascular complications. In this work, we first characterized structural modifications induced by the glycation of bovine serum albumin (BSA). A pathophysiological effect of glycated BSA was identified in primary cultures of human adipocytes as it induces an accumulation of oxidatively modified proteins in these cell…
The effect of oral hormone replacement therapy on lipoprotein profile, resistance of LDL to oxidation and LDL particle size
2001
Abstract Objectives: To disclose if oral estradiol (E 2 ), alone or in combination with natural progesterone (P) or medroxyprogesterone acetate (MPA), may modify the oxidizability of low density lipoprotein (LDL), and if the effect is achieved at physiological dosages. LDL oxidizability was assessed by the resistance to oxidation by copper and by the particle size profile, since small particles have increased oxidation susceptibility. Methods: Thirty-three women received two consecutive, two-month length doses of 1 and 2 mg/day of oral E 2 . They were then randomly assigned to a fourteen-day treatment of 2 mg/day E 2 plus either 300 mg/day P or 5 mg/day MPA. A parallel group of experiments …
Initiation and progression of atherosclerosis – enzymatic or oxidative modification of low-density lipoprotein?
2006
AbstractAtherosclerosis is widely regarded as a chronic inflammatory disease that develops as a consequence of entrapment of low-density lipoprotein (LDL) in the arterial intima. Native LDL lacks inflammatory properties, so the lipoprotein must undergo biochemical alterations to become atherogenic. Among several other candidates, two different concepts of lipoprotein modification are propagated, the widespread oxidation hypothesis and the less common E-LDL hypothesis, which proposes that modification of LDL occurs through the action of ubiquitous hydrolytic enzymes (enzymatically modified LDL or E-LDL) rather than oxidation. By clearly distinguishing between the initiation and progression o…
Elevated Expression of Liver γ-Cystathionase Is Required for the Maintenance of Lactation in Rats
1999
Liver gamma-cystathionase activity increases in rats during lactation; its inhibition due to propargylglycine is followed by a significant decrease in lactation. This is reversible by N-acetylcysteine administration. To study the role of liver gamma-cystathionase and the intertissue flux of glutathione during lactation, we used lactating and virgin rats fed liquid diets. Virgin rats were divided into two groups as follows: one group was fed daily a diet containing the same amount of protein that was consumed the previous day by lactating rats (high protein diet-fed rats); the other virgin group was fed the normal liquid diet (control). The expression and activity of liver gamma-cystathionas…
Exercise restores decreased physical activity levels and increases markers of autophagy and oxidative capacity in myostatin/activin blocked mdx mice
2013
The importance of adequate levels of muscle size and function and physical activity is widely recognized. Myostatin/activin blocking increases skeletal muscle mass but may decrease muscle oxidative capacity and can thus be hypothesized to affect voluntary physical activity. Soluble activin receptor IIB (sActRIIB-Fc) was produced to block myostatin/activins. Modestly dystrophic mdx mice were injected with sActRIIB-Fc or PBS with or without voluntary wheel running exercise for 7 wk. Healthy mice served as controls. Running for 7 wk attenuated the sActRIIB-Fc-induced increase in body mass by decreasing fat mass. Running also enhanced/restored the markers of muscle oxidative capacity and autoph…
Hyperoxemia caused by resuscitation with pure oxygen may alter intracellular redox status by increasing oxidized glutathione in asphyxiated newly bor…
2002
In a prospective, randomized, blinded trial we have studied the effects of resuscitation upon oxygenation in a group of asphyxiated newly born infants receiving room air or 100% oxygen as the gas source. During the acute phase of asphyxia and until the resuscitation procedure concluded, we determined serial blood gases as well as reduced and oxidized glutathione, enzymes involved in the glutathione redox cycle, and antioxidant enzyme activities. The use of 100% oxygen caused a remarkable increase of partial pressures of oxygen in arterial blood, with values that were frequently above physiological levels (>100 mm Hg). In addition, we have found a significant correlation between hyperoxemia …