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See detailESR Investigation of Chemical Exchange in Geminally Diphosphorylated Linear Nitroxide Radicals
Rockenbauer, Antal; Olive, Gilles ULg; Rozanska, Xavier et al

in Journal of Physical Chemistry A (2004), 108(25), 5484-5489

For geminally diphosphorylated linear nitroxide radicals, a marked line width alternation (LWA) can be observed. The LWA appears irrespectively whether the investigated radicals R¢¢N(O¥)C(P(O)(OEt)2)2R¢ ... [more ▼]

For geminally diphosphorylated linear nitroxide radicals, a marked line width alternation (LWA) can be observed. The LWA appears irrespectively whether the investigated radicals R¢¢N(O¥)C(P(O)(OEt)2)2R¢ contain any chiral group or not. If R¢¢ ) tert-butyl and R¢ ) H, the small â-hydrogen coupling indicates a completely blocked rotation around the N-C ó-bond and the LWA can be assigned to a chemical exchange between conformations in which the phosphoryl groups have a symmetric and a nonsymmetric geometry. The conformational change is accompanied by the deformation of the CP2 bonding angle and the rate of exchange is slowed in pentane for which the solvent molecules can be trapped by the chelating phosphoryl groups. If R¢¢ ) benzyl, both the proton hyperfine lines of the CH2 group and the phosphorus lines of the CP2 group produce a LWA; two coalescences can be observed. In the case of a chiral R¢¢ group (R¢¢ ) secondary butyl, R¢ ) methyl) a tentative four-site model can explain the highly complex LWA. [less ▲]

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See detailESR spectroscopy for the study of an inflammation-induced AKI cellular model
Quoilin, Caroline ULg; Mouithys-Mickalad, Ange ULg; Gallez, Bernard et al

Poster (2012, November)

The kidney is faced to an impairment of oxygen extraction during sepsis which is well-known to be a risk factor for the development of acute kidney injury (AKI). Recent research activities in the ... [more ▼]

The kidney is faced to an impairment of oxygen extraction during sepsis which is well-known to be a risk factor for the development of acute kidney injury (AKI). Recent research activities in the mechanisms involved in the development of AKI in sepsis emphasize the central role of hemodynamic and inflammatory events. More particularly, two mechanisms are suggested to explain the inability of the injured kidney to extract oxygen: tissue hypoxia and cellular energetic metabolism dysfunction. Our working hypothesis of the pathophysiology of AKI is based on cellular respiratory dysfunction due to the inflammatory response inherent to sepsis. To study the mechanism of oxygen regulation in inflammation-induced acute kidney injury, we investigate the effects of a bacterial endotoxin (lipopolysaccharide, LPS) on the basal respiration of proximal tubular epithelial cells (HK-2) by ESR oximetry. This method has shown that HK-2 cells exhibit a decreased oxygen consumption rate when treated with LPS. Surprisingly, this cellular respiration alteration persists even after the stress factor was removed. We suggested that this irreversible decrease in renal oxygen consumption after LPS challenge is related to a pathologic metabolic down-regulation such as a lack of oxygen utilization by cells. This decrease was accompanied by increased nitric oxide (NO) production as measured by a spin trapping technique using ESR spectroscopy. This method is based on the trapping of NO by a metal-chelator complex consisting of N-methyl-D-glucamine dithiocarbamate (MGD) and reduced iron (Fe2+) forming a water-soluble NO-FeMGD complex detected by ESR. Since inducible NO synthase (iNOS) has been shown to play an important role in sepsis-induced AKI, the iNOS inhibitor L-NMMA (L-NG-monomethyl Arginine citrate) was tested in this in vitro model. L-NMMA blocked NO generation and permitted the HK-2 cells to recover a normal cellular respiration. Overall, ESR spectroscopy and the model of HK-2 cells exposed to LPS displays some key features of inflammation-induced acute kidney injury. [less ▲]

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See detailESR studies of the in-situ nitroxide-mediated polymerization (NMP) of styrene using a nitrone
Sciannamea, Valérie; Bernard, M.; Catala, J.-M. et al

Conference (2004, November 26)

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See detailESR study of Bacteriochlorin a incorporation into membranes models
Hoebeke, Maryse ULg

Scientific conference (1999)

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See detailESR technique for non invasive way to quantify cyclodextrins effect on cell membranes
Grammenos, Angeliki ULg; Mouithys-Mickalad, Ange ULg; Guelluy, Pierre-Henri ULg et al

in Biochemical and Biophysical Research Communications (2010)

A new way to study the action of cyclodextrin was developed to quantify the damage caused on cell membrane and lipid bilayer. The Electron Spin Resonance (ESR) spectroscopy was used to study the action of ... [more ▼]

A new way to study the action of cyclodextrin was developed to quantify the damage caused on cell membrane and lipid bilayer. The Electron Spin Resonance (ESR) spectroscopy was used to study the action of Randomly methylated-beta-cyclodextrin (Rameb) on living cells (HCT-116). The relative anisotropy observed in ESR spectrum of nitroxide spin probe (5-DSA and cholestane) is directly related to the rotational mobility of the probe,which can be further correlated with themicroviscosity. The use of ESR probes clearly shows a close correlation between cholesterol contained in cells and cellular membrane microviscosity. This study also demonstrates the Rameb ability to extract cholesterol and phospholipids in time- and dose-dependent ways. In addition, ESR spectra enabled to establish that cholesterol is extracted from lipid rafts to form stable aggregates. The present work supports that ESR is an easy, reproducible and noninvasive technique to study the effect of cyclodextrins on cell membranes. [less ▲]

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See detailAn ESR, Mass Spectrometry and Fluorescence microscopy approach to study the stearic acid derivatives anchoring in cells
Grammenos, Angeliki ULg; Fillet, Marianne ULg; Collodoro, Mike et al

in Applied Magnetic Resonance (2012)

Lateral phase separations in biological membranes are of great interest, making Electron Spin Resonance (ESR) spectroscopy combined with spin labelling a non destructive and sensitive technique for the ... [more ▼]

Lateral phase separations in biological membranes are of great interest, making Electron Spin Resonance (ESR) spectroscopy combined with spin labelling a non destructive and sensitive technique for the study of lipid rafts. This is currently accepted that spin probe localization is on the plasma membrane. However, no study confirms this hypothesis. Herein, we report, for the first time, an accurate multi spectral method for the quantification of lipid spin label presence in every sub-cellular fraction. Cells were incubated with 5-doxyl stearic acid derivative and then sub-fractionated. Results of our multimodal spectroscopy approach ubiquitously demonstrate that the presence of ESR spin label only sets in the plasma membranes. [less ▲]

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See detailESRA guidelines for the use of epidural opioids
Aguilar, J. L.; Benhamou, D.; Bonnet, F. et al

in International Monitor on Regional Anaesthesia (1997), 9

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See detailEssai comparatif de deux antalgiques, la floctafénine et le paracétamol, au cours de l’arthrose des membres inférieurs
Lequesne, M; Fannius, J; Reginster, Jean-Yves ULg et al

in Revue du Rhumatisme (1997), 64(5), 349-355

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See detailEssai d’adaptation du K-ABC à une population d’enfants avec trisomie 21
Frenkel, Stéphanie ULg; Lagneau, Frédéric; Vandromme, Luc

in Enfance : Psychologie, Pédagogie, Neuropsychiatrie, Sociologie (2005), 4

Facing the lack of psychometric tools, adapted to atypical populations, the present article constitutes the first section of a study that aims at evaluating the use, in a suitable manner, of the K-ABC ... [more ▼]

Facing the lack of psychometric tools, adapted to atypical populations, the present article constitutes the first section of a study that aims at evaluating the use, in a suitable manner, of the K-ABC test with child and adolescent populations carrying a Down’s syndrome. Following a question review on a set of works that put forward the heterogenic evaluating tools used with deficient subjects, this article proposed a solution to the problem raised by the analysis of results obtained with the K-ABC test of students with Down’s syndrome (i.e., standard notes, degrees of age development of subjects, total intake vs. percentages of good responses). Statistical data screening allows the examiner to determine how individuals how continue in further testing. In a sense, these « subtests » clarify the level of performance and the cognitive efficiency of the target subjects. [less ▲]

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See detailEssai d'adpatation de l'index de handicap vocal (VHI) à la voix chantée.
Morsomme, Dominique ULg

Conference (2005, October 09)

L’index de handicap vocal de Jacobson et al (Voice Handicap Index) ne traduit pas les difficultés éprouvées par le chanteur. Notre étude vise à adapter le Voice Handicap Index à la voix chantée et à en ... [more ▼]

L’index de handicap vocal de Jacobson et al (Voice Handicap Index) ne traduit pas les difficultés éprouvées par le chanteur. Notre étude vise à adapter le Voice Handicap Index à la voix chantée et à en évaluer la fiabilité et la cohérence. Pour obtenir cette première échelle, nous avons procédé selon trois étapes. La première a consisté à modifier les items et à en créer d’autres. La deuxième nous a amené à mesurer la stabilité test-re test et la cohérence interne des items adaptés ou créés sur des groupes de chanteurs dysodiques et des professionnels de la voix. La troisième étape a consisté à évaluer la fiabilité et la cohérence de 31 items sur une population homogène de 132 chanteurs classiques avec et sans trouble vocal répartis en trois groupes. Le premier groupe comprenait 95 chanteurs normophoniques, le deuxième 37 chanteurs dysphoniques et le troisième constituait le groupe contrôle avec 20 sujets non chanteurs sans plainte vocale. Les résultats statistiques montrent une bonne stabilité test-retest (ICC=0.949 ; Rho : 0.912 ; Bland et Altman [-010.19, +13.23]. La cohérence interne de chaque sous échelle (alpha de Cronbach) est bonne (>0.70). Les corrélations entre les trois sous-échelles sont modérées (rho entre sous échelles fonctionnelle et émotionnelle : 0.58 ; entre émotionnelle et physique : 0.64 ; et entre fonctionnelle et physique : 0.78). Chaque sous-échelle mesure une dimension particulière tout en restant homogène entre elles. Quatre variables ont une influence significative sur les résultats: la pathologie (p<0.001), le fait d’être chanteur professionnel (p<0.001), l’effet de la répétition (p=0.003), le fait d’être choriste (p=0.002). Le V.H.I. adapté aux chanteurs se révèle fiable, valide et adapté à la population de chanteurs classiques dysodiques. [less ▲]

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