Evolution of phytosterols in Chardonnay grape berry skins during last stages of ripening

This study presents the results of rapid phytosterols analysis in grape skins during last stages of ripening. The analysis is related to the evolution of sterol content by comparison with ripening degree on two vineyards of Chardonnay grape variety in Burgundy: Meursault ler Cru and Hautes Cotes de Beaune. The characterization of sterols is realized by using combined gas chromatography-mass spectrometry from trimethylsilyl ethers of sterols. After optimization of extraction by azeotropic mixture (chloroform/methanol 2:1 v/v), the analysis allows to identify four sterols in grape skins: beta-sitosterol, campesterol, stigmasterol and lanosterol. In all the samples, beta-sitosterol is the major phytosterol (86 to 89 % of the total detected phytosterols). The evolution of phytosterols content during last stages of ripening shows a similar comportment of β-sitosterol, campesterol and stigmasterol in grape skins: the maturation induces a loss of phytosterols in grape skins. An increase of phytosterol contents occurs at peak maturity and can be related with over-maturation phenomenon. The relationship between phytosterol content in grape skins and S/A ratio indicates a markedly negative correlation

31P Magnetic resonance spectroscopy study of phosphocreatine recovery kinetics in skeletal muscle: the issue of intersubject variability

AbstractWe have analyzed by 31P MRS the relationship between kinetic parameters of phosphocreatine (PCr) recovery and end-of-exercise status under conditions of moderate and large acidosis induced by dynamic exercise. Thirteen healthy subjects performed muscular contractions at 0.47 Hz (low frequency, moderate exercise) and 0.85 Hz (high frequency, heavy exercise). The rate constant of PCr resynthesis (kPCr) varied greatly among subjects (variation coefficients: 43 vs. 57% for LF vs. HF exercises) and protocols (kPCr values: 1.3±0.5 min−1 vs. 0.9±0.5 min−1 for LF vs. HF exercises, P<0.03). The large intersubject variability can be captured into a linear relationship between kPCr, the amount of PCr consumed ([PCr2]) and pH reached at the end of exercise (pHend) (kPCr=−3.3+0.7 pHend-0.03 [PCr2]; P=0.0007; r=0.61). This dual relationship illustrates that mitochondrial activity is affected by end-of-exercise metabolic status and allows reliable comparisons between control, diseased and trained muscles. In contrast to kPCr, the initial rate of PCr recovery and the maximum oxidative capacity were always constant whatever the metabolic conditions of end-of-exercise and can then be additionally used in the identification of dysfunctions in the oxidative metabolic pathway

Deletion of TRAAK Potassium Channel Affects Brain Metabolism and Protects against Ischemia

Cerebral stroke is a worldwide leading cause of disability. The two-pore domain K(+) channels identified as background channels are involved in many functions in brain under physiological and pathological conditions. We addressed the hypothesis that TRAAK, a mechano-gated and lipid-sensitive two-pore domain K(+) channel, is involved in the pathophysiology of brain ischemia. We studied the effects of TRAAK deletion on brain morphology and metabolism under physiological conditions, and during temporary focal cerebral ischemia in Traak(-/-) mice using a combination of in vivo magnetic resonance imaging (MRI) techniques and multinuclear magnetic resonance spectroscopy (MRS) methods. We provide the first in vivo evidence establishing a link between TRAAK and neurometabolism. Under physiological conditions, Traak(-/-) mice showed a particular metabolic phenotype characterized by higher levels of taurine and myo-inositol than Traak(+/+) mice. Upon ischemia, Traak(-/-) mice had a smaller infarcted volume, with lower contribution of cellular edema than Traak(+/+) mice. Moreover, brain microcirculation was less damaged, and brain metabolism and pH were preserved. Our results show that expression of TRAAK strongly influences tissue levels of organic osmolytes. Traak(-/-) mice resilience to cellular edema under ischemia appears related to their physiologically high levels of myo-inositol and of taurine, an aminoacid involved in the modulation of mitochondrial activity and cell death. The beneficial effects of TRAAK deletion designate this channel as a promising pharmacological target for the treatment against stroke

Magnetic resonance imaging of the neuroprotective effect of xaliproden in rats

RATIONALE AND OBJECTIVES: The neurotrophic effect of Xaliproden has been followed using sequential cerebral magnetic resonance imaging (MRI) in rats with vincristine-induced brain lesion as a model of Alzheimer disease. METHODS: Nineteen rats received an intraseptal injection of vincristine on day 0, followed by a daily gavage with either the vehicle (Tween-20 1%) (n = 10) or Xaliproden (10 mg/kg) (n = 9). Eight sham-operated controls received a daily gavage with either the vehicle (n = 4) or Xaliproden (n = 4). Brain MR imaging was performed at 4.7 T on a Biospec 47/30 MR system before surgery then 3, 7, 10, and 14 days after surgery. RESULTS: At day 3 following vincristine injection, an increase in MR signal intensity in the septum was observed on T2-weighted images. This increase was maximal at day 10, and remained stable until day 14. Daily treatment with Xaliproden delayed the appearance of hypersignals until day 7 and reduced by Ca. 50% the magnitude of the increase in signal intensity from day 10. No changes were observed in the hippocampus. CONCLUSION: Quantitative MRI objectifies noninvasively the neuroprotective effect of Xaliproden on rat brain anatomy

Hybrid organo-inorganic materials of the VPO system

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The 18 kDa Translocator Protein (Peripheral Benzodiazepine Receptor) Expression in the Bone of Normal, Osteoprotegerin or Low Calcium Diet Treated Mice

The presence of the translocator protein (TSPO), previously named as the mitochondrial or peripheral benzodiazepine receptor, in bone cells was studied in vitro and in situ using RT-qPCR, and receptor autoradiography using the selective TSPO ligand PK11195

Prime Focus Spectrograph (PFS) for the Subaru Telescope: Overview, recent progress, and future perspectives

PFS (Prime Focus Spectrograph), a next generation facility instrument on the 8.2-meter Subaru Telescope, is a very wide-field, massively multiplexed, optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed over the 1.3 deg field of view. The spectrograph has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously observe spectra from 380nm to 1260nm in one exposure at a resolution of ~1.6-2.7A. An international collaboration is developing this instrument under the initiative of Kavli IPMU. The project is now going into the construction phase aiming at undertaking system integration in 2017-2018 and subsequently carrying out engineering operations in 2018-2019. This article gives an overview of the instrument, current project status and future paths forward.Comment: 17 pages, 10 figures. Proceeding of SPIE Astronomical Telescopes and Instrumentation 201

Association of the CpG Methylation Pattern of the Proximal Insulin Gene Promoter with Type 1 Diabetes

The insulin (INS) region is the second most important locus associated with Type 1 Diabetes (T1D). The study of the DNA methylation pattern of the 7 CpGs proximal to the TSS in the INS gene promoter revealed that T1D patients have a lower level of methylation of CpG -19, -135 and -234 (p = 2.10−16) and a higher methylation of CpG -180 than controls, while methylation was comparable for CpG -69, -102, -206. The magnitude of the hypomethylation relative to a control population was 8–15% of the corresponding levels in controls and was correlated in CpGs -19 and -135 (r = 0.77) and CpG -135 and -234 (r = 0.65). 70/485 (14%) of T1D patients had a simultaneous decrease in methylation of CpG -19, -135, -234 versus none in 317 controls. CpG methylation did not correlate with glycated hemoglobin or with T1D duration. The methylation of CpG -69, -102, -180, -206, but not CpG -19, -135, -234 was strongly influenced by the cis-genotype at rs689, a SNP known to show a strong association with T1D. We hypothesize that part of this genetic association could in fact be mediated at the statistical and functional level by the underlying changes in neighboring CpG methylation. Our observation of a CpG-specific, locus-specific methylation pattern, although it can provide an epigenetic biomarker of a multifactorial disease, does not indicate whether the reported epigenetic pattern preexists or follows the establishment of T1D. To explore the effect of chronic hyperglycemia on CpG methylation, we studied non obese patients with type 2 diabetes (T2D) who were found to have decreased CpG-19 methylation versus age-matched controls, similar to T1D (p = 2.10−6) but increased CpG-234 methylation (p = 5.10−8), the opposite of T1D. The causality and natural history of the different epigenetic changes associated with T1D or T2D remain to be determined

Role of the IRS-1 and/or -2 in the pathogenesis of insulin resistance in Dahl salt-sensitive (S) rats

Insulin resistance is a common finding in hypertensive humans and animal models. The Dahl salt-sensitive (S) rat is an ideal model of genetically predetermined insulin resistance and salt-sensitive hypertension. Along the insulin signaling pathway, the insulin receptor substrates 1 and 2 (IRS-1 and -2) are important mediators of insulin signaling. IRS-1 and/or IRS-2 genetic variant(s) and/or enhanced serine phosphorylation correlate with insulin resistance. The present commentary was designed to highlight the significance of IRS-1 and/or -2 in the pathogenesis of insulin resistance. An emphasis will be given to the putative role of IRS-1 and/or -2 genetic variant(s) and serine phosphorylation in precipitating insulin resistance