Search results for " element"
showing 10 items of 2679 documents
Patterns and rates of nucleotide substitution, insertion and deletion in the endosymbiont of antsBlochmannia floridanus
2009
Genome reduction is a general process that has been studied in numerous symbiotic bacteria associated with insects. We investigated the last stages of genome degradation in Blochmannia floridanus, a mutualistic bacterial endosymbiont of the ant Camponotus floridanus. We determined the tempo (rates of insertion and deletion) and mode (size and number of insertion-deletion events) of the process in the last 200,000 years by analysing a total of 16 intergenic regions in several strains of this endosymbiont from different ant populations. We provide the first calculation of the reduction rate for noncoding DNA in this endosymbiont (2.2 x 10(-8) lost nucleotides/site/year) and compare it with th…
Carcinogenic aspect of xenobiotic molecules belonging to the peroxisome proliferator family.
1999
It is known that a short-term exposure of rat, mice or incubation of hepatic cells with fibrate molecules leads to increase in peroxisome number and cell hyperplasia. Further, long-term incubation of cells (at least a year) show transformed characteristics with foci and nodules. To explain the hepatocarcinogenic effect of peroxisome proliferators in rodents we studied the effect of peroxisome proliferators on rat liver oncogenes expression. Earlier, we reported an increase in liver and kidney mRNA level of c-myc and N-myc. Since several metabolic genes are activated by PPAR (peroxisome proliferators activated receptor) through a PPRE (peroxisome proliferator response element), we suggest th…
Moderate consumption of beer reduces liver triglycerides and aortic cholesterol deposit in LDLr-/- apoB100/100 mice.
2006
This study was designed to address the effects of a moderate consumption of beer on serum and liver lipid parameters and on the development of aortic lesions in a mouse model associated with a human atherogenic lipoprotein profile. LDLr(-/-) apoB(100/100) mice received each day during 12 weeks either water, mild beer (0.570g of ethanol/kg of body weight) or ethanol-free beer in a single pure dose. Serum and liver lipid parameters were analyzed and atherosclerotic lesions were estimated in heart and aorta through their total cholesterol content. mRNA levels of enzymes and receptors involved in lipoprotein uptake, in fatty acid esterification and oxidation, and in reverse cholesterol transpor…
Dietary cholic acid lowers plasma levels of mouse and human apolipoprotein A-I primarily via a transcriptional mechanism
2000
To induce dietary atherosclerosis in mice, high-fat/high-cholesterol (HF) diets are frequently supplemented with cholic acid (CA). This diet produces low plasma levels of high-density lipoprotein (HDL) and high levels of low-density lipoprotein (LDL). However, HF diets without any added CA, which more closely resemble human diets, increase levels of both HDL and LDL, suggesting that CA may be responsible for the lowering of HDL. Our aim was to examine the potential mechanism responsible for the lowering of HDL. Nontransgenic (NTg) C57BL mice and apoA-I-transgenic (apoAI-Tg) mice, with greatly increased basal apoA-I and HDL levels, were used. Mice were fed the following four diets: control (…
Plant sterols from foods in inflammation and risk of cardiovascular disease: a real threat?
2014
High dietary intakes of cholesterol together with sedentary habits have been identified as major contributors to atherosclerosis. The latter has long been considered a cholesterol storage disease; however, today atherosclerosis is considered a more complex disease in which both innate and adaptive immune-inflammatory mechanisms as well as bacteria play a major role, in addition to interactions between the arterial wall and blood components. This scenario has promoted nutritional recommendations to enrich different type of foods with plant sterols (PS) because of their cholesterol-lowering effects. In addition to cholesterol, PS can also be oxidized during food processing or storage, and the…
Impact of Aortic Stenosis on Myofiber Stress: Translational Application of Left Ventricle-Aortic Coupling Simulation
2020
The severity of aortic stenosis (AS) has traditionally been graded by measuring hemodynamic parameters of transvalvular pressure gradient, ejection jet velocity, or estimating valve orifice area. Recent research has highlighted limitations of these criteria at effectively grading AS in presence of left ventricle (LV) dysfunction. We hypothesized that simulations coupling the aorta and LV could provide meaningful insight into myocardial biomechanical derangements that accompany AS. A realistic finite element model of the human heart with a coupled lumped-parameter circulatory system was used to simulate AS. Finite element analysis was performed with Abaqus FEA. An anisotropic hyperelastic mo…
Induction of the adrenoleukodystrophy-related gene (ABCD2) by thyromimetics.
2009
X-linked adrenoleukodystrophy (X-ALD) is a peroxisomal disorder caused by mutations in the ABCD1 (ALD) gene. The ABCD2 gene, its closest homolog, has been shown to compensate for ABCD1 deficiency when overexpressed. We previously demonstrated that the ABCD2 promoter contains a functional thyroid hormone response element. Thyroid hormone (T3) through its receptor TRbeta can induce hepatic Abcd2 expression in rodents and transiently normalize the VLCFA level in fibroblasts of Abcd1 null mice. In a therapeutic perspective, the use of selective agonists of TRbeta should present the advantage to be devoid of side effects, at least concerning the cardiotoxicity associated to TRalpha activation. I…
Corticotropin-Releasing Hormone-Mediated Induction of Intracellular Signaling Pathways and Brain-Derived Neurotrophic Factor Expression Is Inhibited …
2005
CRH receptor (CRHR) 1 and the cannabinoid receptor 1 (CB1) are both G protein-coupled receptors. Activation of CRHR1 leadstoincreasesincAMPproductionandphosphorylationof the transcription factor cAMP response element-binding protein (CREB). In contrast, CB1 is negatively coupled to the cAMP signaling cascade. In this study, we analyzed a putative interaction between these two systems focusing on the regulation of the expression of brain-derived neurotrophic factor (BDNF), a CREB-regulated gene. In situ hybridization revealed coexpression of CRHR1 and CB1 receptors in the granular layer of the cerebellum. Therefore, we analyzed the effects of CRH and the CB1 agonist WIN-55,212-2 on BDNF expr…
A common mechanism of action of the selective serotonin reuptake inhibitors citalopram and fluoxetine: Reversal of chronic psychosocial stress-induce…
2010
The transcription factor CREB regulates adaptive responses like memory consolidation, addiction, and synaptic refinement. Recently, chronic psychosocial stress as animal model of depression has been shown to stimulate CREB transcriptional activity in the brain; this stimulation was prevented by treatment with the antidepressant imipramine, which inhibits both noradrenaline and serotonin reuptake. However, it was unknown whether the selective inhibition of serotonin reuptake is sufficient for inhibition of stress-induced CREB activation, as it is for the clinical antidepressant effect. Therefore, the effect of two selective serotonin reuptake inhibitors (SSRIs), citalopram and fluoxetine, wa…
Intraoperative neural electrode for continuous monitoring of nerve function
2009
Nerve damage is still a major concern in all types of surgery and may result in permanent nerve injury. Real time nerve monitoring can reduce the risk of nerve lesions by continuous surveillance of nerve integrity. A stable proximal stimulation of the nerve and recording at the effector organ is essential and the electrodes should not significantly influence the surgical intervention.