References of "Hoebeke, Maryse"
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See detailImagerie médicale - bases physiques
Seret, Alain ULg; Hoebeke, Maryse ULg

Book published by Editions de l'Université de Liège (2006)

The book explains the physical foundations of the most common in-vivo medical imaging modalities. It is written for readers having a basic knowledge of physics. However the most essential physical ... [more ▼]

The book explains the physical foundations of the most common in-vivo medical imaging modalities. It is written for readers having a basic knowledge of physics. However the most essential physical phenomenon and their properties are described. Exploring the electromagnetic spectrum from the shortest to the longest wavelengths the book deals with nuclear imaging, RX imaging, endoscopy, thermography and MRI. Acoustic wave and ultrasonography is the next subject. The book ends with the digital image and a few radioprotection notions. [less ▲]

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See detailPhysical and chemical properties of pyropheophorbide)a-methyl ester in ethanol, phosphate buffer and aqueous dispersion of small unilamellar dimyristoyl-L-a-phosphatidylcholine vesicles
Delanaye, Lisiane; Bahri, Mohamed Ali ULg; Tfibel, Francis et al

in Photochemical & Photobiological Sciences (2006), 5

The aggregation process of pyropheophorbide-a methyl ester (PPME), a second generation hotosensitizer, was investigated in various solvents. Absorption and fluorescence spectra showed that the ... [more ▼]

The aggregation process of pyropheophorbide-a methyl ester (PPME), a second generation hotosensitizer, was investigated in various solvents. Absorption and fluorescence spectra showed that the photosensitizer was under a monomeric form in ethanol as well as in dimyristoyl-L-α-phosphatidylcholine liposomes while it was strongly aggregated in phosphate buffer. A quantitative determination of reactive oxygen species production by PPME in these solvents has been undertaken by electron spin resonance associated with spin trapping technique and absorption spectroscopy. In phosphate buffer, both electron spin resonance and absorption measurements led to the conclusion that singlet oxygen production was not detectable while hydroxyl radical production was very weak. In liposomes and ethanol, singlet oxygen and hydroxyl radical production increased highly; the singlet oxygen quantum yield was determined to be 0.2 in ethanol and 0.13 in liposomes. The hydroxyl radical production origin was also investigated. Singlet oxygen was formed from PPME triplet state deactivation in presence of oxygen. Indeed, the triplet state formation quantum yield of PPME was found to be about 0.23 in ethanol, 0.15 in liposomes (too small to be measured in PBS). [less ▲]

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See detailStudy of neuronal cells preconditionning
Guelluy, Pierre-Henri ULg; Mouithys-Mickalad, Ange ULg; Deby, Ginette et al

Poster (2005, November 25)

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See detailStudy of neuronal preconditionning by ESR
Guelluy, Pierre-Henri ULg; Mouithys-Mickalad, Ange ULg; Deby, Ginette et al

Scientific conference (2005, November 17)

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See detailSynoviocytes, not chondrocytes, release free radicals after cycles of anoxia/re-oxygenation
Schneider, Nicole ULg; Mouithys-Mickalad, Ange ULg; Lejeune, Jean-Philippe ULg et al

in Biochemical & Biophysical Research Communications (2005), 334(2), 669-673

By oxymetry and electron paramagnetic resonance (EPR), we investigated the effects of repeated anoxia/re-oxygenation (A/R) periods on the respiration and production of free radicals by synoviocytes ... [more ▼]

By oxymetry and electron paramagnetic resonance (EPR), we investigated the effects of repeated anoxia/re-oxygenation (A/R) periods on the respiration and production of free radicals by synoviocytes (rabbit HIG-82 cell line and primary equine synoviocytes) and equine articular chondrocytes. Three periods of 20 min anoxia followed by re-oxygenation were applied to 10(7)cells; O(2) consumption was measured before anoxia and after each re-oxygenation. After the last A/R, cellular free radical formation was investigated by EPR spectroscopy with spin trapping technique (n=3 for each cell line). Both types of synoviocytes showed a high O(2) consumption, which was slowered after anoxia. By EPR with the spin trap POBN, we proved a free radical formation. Results were similar for equine and rabbit synoviocytes. For chondrocytes, we observed a low O(2) consumption, unchanged by anoxia, and no free radical production. These observations suggest an oxidant activity of synoviocytes, potentially important for the onset of osteoarthritis. [less ▲]

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See detailReactivity towards singlet oxygen of propofol inside liposomes and neuronal cells
Heyne, Belinda; Brault, Daniel; Fontaine-Aupart, Marie-Pierre et al

in Biochimica et Biophysica Acta - General Subjects (2005), 1724

Singlet oxygen (1O2), a reactive oxygen species, has been found to be implicated in many cellular events and pathological disorders.Herein, we investigated the reactivity of 1O2 towards the anaesthetic ... [more ▼]

Singlet oxygen (1O2), a reactive oxygen species, has been found to be implicated in many cellular events and pathological disorders.Herein, we investigated the reactivity of 1O2 towards the anaesthetic agent propofol (PPF) encapsulated within DMPC liposomes. By time resolved luminescence, the rate constant of 1O2 quenching by PPF was evaluated, depending on the location of the sensitizer. The nature of the oxidation product, resulting from the reaction of 1O2 with PPF, was determined using absorption and HPLC techniques. Finally, the in vitro protective effect of PPF towards the1O2-induced neuronal cell toxicity was evaluated in terms of cell viability. [less ▲]

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See detailQuantification of lipid bilayer effective microviscosity and fluidity effect induced by propofol
Bahri, Mohamed Ali ULg; Heyne, Belinda; Hans, Pol ULg et al

in Biophysical Chemistry (2005), 114(1), 53-61

Electron spin resonance (ESR) spectroscopy with nitroxide spin probes was used as a method to probe the liposome microenvironments. The effective microviscosities have been determined from the calibration ... [more ▼]

Electron spin resonance (ESR) spectroscopy with nitroxide spin probes was used as a method to probe the liposome microenvironments. The effective microviscosities have been determined from the calibration of the ESR spectra of the probes in solvent mixtures of known viscosities. In the first time, by measuring ESR order parameter (S ) and correlation time (s c) of stearic spin probes, we have been able to quantify the value of effective microviscosity at different depths inside the liposome membrane. At room temperature, local microviscosities measured in dimyristoyl-l-a phosphatidylcholine (DMPC) liposome membrane at the different depths of 7.8, 16.95, and 27.7 2 were 222.53, 64.09, and 62.56 cP, respectively. In the gel state (10 °C), those microviscosity values increased to 472.56, 370.61, and 243.37 cP. In a second time, we have applied this technique to determine the modifications in membrane microviscosity induced by 2,6-diisopropyl phenol (propofol; PPF), an anaesthetic agent extensively used in clinical practice. Propofol is characterized by a unique phenolic structure, absent in the other conventional anaesthetics. Indeed, given its lipophilic property, propofol is presumed to penetrate into and interact with membrane lipids and hence to induce changes in membrane fluidity. Incorporation of propofol into dimyristoyl-L-alpha-phosphatidylcholine liposomes above the phase-transition temperature (23.9 °C) did not change microviscosity. At 10 °C, an increase of propofol concentration from 0 to 1.0 10 [less ▲]

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See detailStudy of neuronal cells preconditioning by ESR
Guelluy, Pierre-Henri ULg; Mouithys-Mickalad, Ange ULg; Deby-Dupont, G. et al

Conference (2005)

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See detailStudy in human colon cancer cells HCT-116 of PPME photodynamic effect solubilized in DMPC liposomes
Delanaye, L.; Volanti, C.; Jacobs, Nathalie ULg et al

Conference (2005)

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See detailQuantification of lipid bilayer viscosity and fuidity effect induced by propofol.
Bahri, Mohamed Ali ULg; Heyne, Belinda; Hans, Pol ULg et al

Conference (2004, April 23)

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See detailPhysique (J. Kane & M. Sternheim)
Ghosez, Philippe ULg; Hoebeke, Maryse ULg; Llabres, Gabriel ULg

Book published by Dunod - 3rd ed. (2004)

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See detailEffects of COX-2 inhibitors on ROS produced by Chlamydia pneumoniae-primed human promonocytic cells (THP-1)
Mouithys-Mickalad, Ange ULg; Deby, Ginette ULg; Dogné, Jean-Michel ULg et al

in Biochemical and Biophysical Research Communications (2004), 325(4), 1122-1130

Chronic inflammation through foam cells and macrophages is important in atherosclerosis development, and can be considered as therapeutic targets. Cyclooxygenase and NADPH-oxidase were expressed within ... [more ▼]

Chronic inflammation through foam cells and macrophages is important in atherosclerosis development, and can be considered as therapeutic targets. Cyclooxygenase and NADPH-oxidase were expressed within atherosclerotic lesions. Reactive oxygen species produced by NADPH oxidase were found to trigger the cyclooxygenase-2 expression. The effects of preferential COX-2 inhibitors on ROS produced by Chlamydia-primed human monocytes (THP-1 cells) were evaluated by fluorescence, chemiluminescence, oxymetry, and EPR spin trapping. Fluorescence assays showed an increased production of ROS with Chlamydia versus cells primed by 10(-8) M PMA. COX-2 inhibitors inhibited in a dose-dependent manner the luminol-enhanced CL while ibuprofen and diclofenac increased the chemiluminescence response. By EPR spin trapping, COX-2 inhibitors, ibuprofen, and diclofenac, exhibited a dose-dependent inhibiting effect (10 and 100 muM) on the EPR signal appearance. Our cell model combining EPR, chemiluminescence, and oxymetry appeared relevant to study the modulating effects of preferential COX-2 inhibitors on the cell oxidant activity and chronic inflammatory diseases. (C) 2004 Elsevier Inc. All rights reserved. [less ▲]

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See detailIn vitro evaluation of glutathione peroxidase (GPx)-like activity and antioxidant properties of some Ebselen analogues
Mouithys-Mickalad, Ange ULg; Mareque-Faez, Juan; Chistiaens, U. et al

in Redox Report : Communications in Free Radical Research (2004), 9(2), 81-87

Four analogues of Ebselen were synthesized and their glutathione peroxidase activity and antioxidant property evaluated and compared to Ebselen. Among the studied compounds, only diselenide [3] exhibited ... [more ▼]

Four analogues of Ebselen were synthesized and their glutathione peroxidase activity and antioxidant property evaluated and compared to Ebselen. Among the studied compounds, only diselenide [3] exhibited both glutathione peroxidase activity and radical-scavenging capability. Compounds [3] and [4] showed a strong inhibitory effect (53% and 43%, respectively) on the lipid peroxidation of linoleic acid compared to Ebselen and selenide derivatives ([1] and [2]) which were less active (28%, 26% and 18% inhibition, respectively). A concentration-dependent inhibitory effect was also found in the model of the formation of ABTS*+ radical cation: 65% and 89% inhibition for compound [3] at 10(-4) M and 5 x 10(-5) M, respectively, and 68% and 90% for compound [4], compared to 14% and 52% inhibition for Ebselen and the diselenides [1] and [2] (29%, 46% and 45%, 68%, respectively). By EPR spin trapping technique, the following inhibitory profile of the Ebselen analogues was observed towards the formation of thiyl radicals: Ebselen = [3]>[1]>[2]>[4]. Studies with compound [3] are in progress on oxidative stress cell models. [less ▲]

Detailed reference viewed: 34 (2 ULg)