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See detailMatrix Metalloproteinase-9 gene induction by a truncated oncogenic NF-κB2 protein involves the recruitment of MLL1 and MLL2 H3K4 histone methyltransferase complexes.
Robert, Isabelle ULg; Aussems, Marie ULg; Keutgens, Aurore ULg et al

in Oncogene (2009), 28(13), 1626-1638

Constitutive nuclear factor (NF)-kappaB activation in haematological malignancies is caused in several cases by loss of function mutations within the coding sequence of NF-kappaB inhibitory molecules such ... [more ▼]

Constitutive nuclear factor (NF)-kappaB activation in haematological malignancies is caused in several cases by loss of function mutations within the coding sequence of NF-kappaB inhibitory molecules such as IkappaBalpha or p100. Hut-78, a truncated form of p100, constitutively generates p52 and contributes to the development of T-cell lymphomas but the molecular mechanism underlying this oncogenic potential remains unclear. We show here that MMP9 gene expression is induced through the alternative NF-kappaB-activating pathway in fibroblasts and also on Hut-78 or p52 overexpression in fibroblasts as well as in lymphoma cells. p52 is critical for Hut-78-mediated MMP9 gene induction as a Hut-78 mutant as well as other truncated NF-kappaB2 proteins that are not processed into p52 failed to induce the expression of this metalloproteinase. Conversely, MMP9 gene expression is impaired in p52-depleted HUT-78 cells. Interestingly, MLL1 and MLL2 H3K4 methyltransferase complexes are tethered by p52 on the MMP9 but not on the IkappaBalpha promoter, and the H3K4 trimethyltransferase activity recruited on the MMP9 promoter is impaired in p52-depleted HUT-78 cells. Moreover, MLL1 and MLL2 are associated with Hut-78 in a native chromatin-enriched extract. Thus, we identified a molecular mechanism by which the recruitment of a H3K4 histone methyltransferase complex on the promoter of a NF-kappaB-dependent gene induces its expression and potentially the invasive potential of lymphoma cells harbouring constitutive activity of the alternative NF-kappaB-activating pathway. [less ▲]

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See detailNanocoatings of inorganic surfaces by the layer by layer (LbL) technology
Faure, Emilie ULg; Zocchi, Germaine ULg; Lenoir, Sandrine et al

Poster (2009, April 02)

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See detailAnomalous behaviour in the diffusion of polyethylene oxide through dialysis membrane
Vignisse, Julie ULg; Gustin, Audrey; Lespineux et al

Poster (2009, April 01)

Dialysis is a common technique adopted in biochemistry to purify biopharmaceutical drugs. This methodology is also of interest in macromolecular chemistry and pharmaceutical nanotechnology in order to ... [more ▼]

Dialysis is a common technique adopted in biochemistry to purify biopharmaceutical drugs. This methodology is also of interest in macromolecular chemistry and pharmaceutical nanotechnology in order to purify synthetic macromolecules and nanodrug carriers designed for drug delivery purposes. However, based on their original applications, the diffusion characteristic of the dialysis membrane is given in respect to the diffusion rate of globular proteins. So the diffusion capacity is function of molecular weight cut-off, i.e. corresponding to the maximum molecular weight of a globular macromolecule to be able to cross the membrane. The diffusion kinetics of synthetic macromolecules is expected to differ significantly from globular proteins due to at least the following differences : Specific relationship between hydrodynamic diameter and molecular weight, Flexibility Ionic density Solubility/miscibility/adsorption behaviour with the dialysis membrane Polymer chain entanglement above a critical concentration. In view to validate the application of this technique to purify synthetic macromolecules, we have compared the diffusion ability of neutral polyethyetylene oxide (PEO) standards or poly(dimethyl-aminoethyl-methacrylate) (PMADAM) to protein standards (human insulin and ovalbumin). [less ▲]

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See detailAndrogen receptor controls EGFR and ERBB2 gene expression at different levels in prostate cancer cell lines.
Pignon, Jean-Christophe ULg; Koopmansch, Benjamin ULg; Nolens, Grégory ULg et al

in Cancer Research (2009), 69(7), 2941-2949

EGFR or ERBB2 contributes to prostate cancer (PCa) progression by activating the androgen receptor (AR) in hormone-poor conditions. Here, we investigated the mechanisms by which androgens regulate EGFR ... [more ▼]

EGFR or ERBB2 contributes to prostate cancer (PCa) progression by activating the androgen receptor (AR) in hormone-poor conditions. Here, we investigated the mechanisms by which androgens regulate EGFR and ERBB2 expression in PCa cells. In steroid-depleted medium (SDM), EGFR protein was less abundant in androgen-sensitive LNCaP than in androgen ablation-resistant 22Rv1 cells, whereas transcript levels were similar. Dihydrotestosterone (DHT) treatment increased both EGFR mRNA and protein levels and stimulated RNA polymerase II recruitment to the EGFR gene promoter, whereas it decreased ERBB2 transcript and protein levels in LNCaP cells. DHT altered neither EGFR or ERBB2 levels nor the abundance of prostate-specific antigen (PSA), TMEPA1, or TMPRSS2 mRNAs in 22Rv1 cells, which express the full-length and a shorter AR isoform deleted from the COOH-terminal domain (ARDeltaCTD). The contribution of both AR isoforms to the expression of these genes was assessed by small interfering RNAs targeting only the full-length or both AR isoforms. Silencing of both isoforms strongly reduced PSA, TMEPA1, and TMPRSS2 transcript levels. Inhibition of both AR isoforms did not affect EGFR and ERBB2 transcript levels but decreased EGFR and increased ERBB2 protein levels. Proliferation of 22Rv1 cells in SDM was inhibited in the absence of AR and ARDeltaCTD. A further decrease was obtained with PKI166, an EGFR/ERBB2 kinase inhibitor. Overall, we showed that ARDeltaCTD is responsible for constitutive EGFR expression and ERBB2 repression in 22Rv1 cells and that ARDeltaCTD and tyrosine kinase receptors are necessary for sustained 22Rv1 cell growth. [less ▲]

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See detailNew magnetic field measurements of beta Cephei stars and slowly pulsating B stars
Hubrig, S.; Briquet, Maryline ULg; De Cat, P. et al

in Astronomische Nachrichten (2009), 330

We present the results of the continuation of our magnetic survey with FORS 1 at the VLT of a sample of B-type stars consisting of confirmed or candidate β Cephei stars and Slowly Pulsating B (hereafter ... [more ▼]

We present the results of the continuation of our magnetic survey with FORS 1 at the VLT of a sample of B-type stars consisting of confirmed or candidate β Cephei stars and Slowly Pulsating B (hereafter SPB) stars, along with a small number of normal B-type stars. A weak mean longitudinal magnetic field of the order of a few hundred Gauss was detected in three β Cephei stars and two stars suspected to be β Cephei stars, in five SPB stars and eight stars suspected to be SPB stars. Additionally, a longitudinal magnetic field at a level larger than 3Ï has been diagnosed in two normal B-type stars, the nitrogen-rich early B-type star HD 52089 and in the B5 IV star HD 153716. Roughly one third of β Cephei stars have detected magnetic fields: Out of 13 β Cephei stars studied to date with FORS 1, four stars possess weak magnetic fields, and out of the sample of six suspected β Cephei stars two show a weak magnetic field. The fraction of magnetic SPBs and candidate SPBs is found to be higher: Roughly half of the 34 SPB stars have been found to be magnetic and among the 16 candidate SPBs eight stars possess magnetic fields. In an attempt to understand why only a fraction of pulsating stars exhibit magnetic fields, we studied the position of magnetic and non-magnetic pulsating stars in the H-R diagram. We find that their domains in the H-R diagram largely overlap, and no clear picture emerges as to the possible evolution of the magnetic field across the main sequence. It is possible that stronger fields tend to be found in stars with lower pulsating frequencies and smaller pulsating amplitudes. A somewhat similar trend is found if we consider a correlation between the field strength and the v sin i-values, i.e. stronger magnetic fields tend to be found in more slowly rotating stars. Based on observations obtained at the European Southern Observatory, Paranal, Chile (ESO programmes 078.D-0140(A), 078.D-0330(A), 079.D-0241(A), and 080.D-0383(A)). [less ▲]

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See detailCRUE DU GAZ CARBONIQUE DANS L'AIR DES GROTTES
Godissart, Jean; Ek, Camille ULg

in EcoKarst (2009)

Carbone dioxide in cave air is strongly increasing for at least forty years.

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See detailLa Coopération au Développement répond à l’impact de la crise financière et économique sur les pays africains à bas revenu – Etude de cas du Sénégal
Paul, Elisabeth ULg; Faye, Ousmane

Report (2009)

Il est désormais reconnu que les pays africains seront touchés par la crise financière et économique mondiale, et ce à travers plusieurs canaux de transmission. Au Sénégal, la crise "externe" intervient à ... [more ▼]

Il est désormais reconnu que les pays africains seront touchés par la crise financière et économique mondiale, et ce à travers plusieurs canaux de transmission. Au Sénégal, la crise "externe" intervient à un moment où l’économie est affaiblie par les conséquences des crises alimentaire et énergétique des deux dernières années, ainsi que par la crise "interne" des finances publiques qui en a (en partie) découlé. Dès lors, le gouvernement a très peu d’espace fiscal pour combattre les effets de la crise mondiale. Si aucune évidence chiffrée n’est encore disponible, les principaux canaux de contagion potentiels de la crise économique au Sénégal sont la réduction des transferts des migrants, le report ou l’annulation de projets d’investissement, ainsi qu’une réduction des exportations et des activités liées au tourisme. Une réduction importante des flux d’aide n’est par contre pas à craindre dans l’immédiat. Les principaux impacts qui découleraient de la crise sont la réduction de la croissance et de l’emploi, de même qu’un appauvrissement direct des ménages bénéficiant de moins de transferts des expatriés. En outre, la réduction des recettes publiques et l’augmentation des pressions sur le budget laissent craindre une augmentation du déficit budgétaire et/ou une réduction des dépenses publiques. S’il n’y a aucune raison de s’alarmer des impacts de la crise mondiale dans l’immédiat, il convient toutefois de bien surveiller les différents canaux de contagion possibles, tout en continuant les efforts de plus longue haleine pour réduire la vulnérabilité structurelle de l’économie sénégalaise (développement intégré du secteur rural dans une perspective de réduction de la dépendance alimentaire, consolidation du tissu économique local), lutter contre la pauvreté et augmenter la protection sociale des plus vulnérables. Pour ce qui est du niveau conjoncturel, il n’existe pas encore de stratégie prête à l’emploi pour faire face aux impacts de la crise. Une révision des stratégies existantes, en particulier au niveau de l’amélioration de la sécurité alimentaire, de l’orientation de la croissance vers les pauvres (notamment par la création d’emplois formels et dans le monde rural) et de la protection sociale, s’imposent afin de fournir les bases à des actions cohérentes et ciblées de la part des partenaires. Vu le faible espace fiscal du gouvernement, une aide des donateurs et dans la mesure du possible, la captation d’autres sources de financement, seront donc nécessaires. Le secteur privé fait entièrement partie des stratégies de croissance du Sénégal, mais son potentiel est encore insuffisamment exploité. Un système de financement innovant pouvant être développé serait d’inciter les migrants à consacrer leurs transferts à des investissements productifs et/ou à de réelles fins de protection sociale à vocation plus universelle. Les donateurs n’ont pas encore réagi de manière coordonnée à la crise "externe", mais avaient réagi assez unanimement à la crise "interne" qui a récemment frappé le Sénégal. Ils peuvent contribuer à atténuer les impacts de la crise et à réduire la vulnérabilité de l’économie tout en s’inscrivant dans les stratégies nationales, à la fois au niveau structurel (infrastructures rurales, gouvernance, extension de la sécurité sociale, etc.) et au niveau conjoncturel (« programme social d’urgence » de large échelle). Une augmentation de l’appui budgétaire est une piste intéressante, pourvu que le pays évite tout dérapage budgétaire, poursuive ses réformes de la gestion des finances publiques vers davantage de contrôles et de transparence, et renforce ses capacités de mise en œuvre des réformes et stratégies nationales. Quant à la coopération belge plus particulièrement, elle a intérêt à renforcer sa complémentarité avec les autres acteurs en bâtissant sur ses principales valeurs ajoutées que sont l’extension de la protection sociale (en particulier dans le domaine de la santé) et des interventions intégrées à plusieurs niveaux dans le domaine du développement rural. [less ▲]

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See detailMesures de flux dans le grand Nord
Heinesch, Bernard ULg; Yernaux, Michel

in FACtuel (2009), 7

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See detailEffects of marginal iron overload on iron homeostasis and immune function in alveolar macrophages isolated from pregnant and normal rats.
Ward, Roberta J; Wilmet, Stephanie; Legssyer, Rachida et al

in Biometals (2009), 22(2), 211-23

The effects of changes in macrophage iron status, induced by single or multiple iron injections, iron depletion or pregnancy, on both immune function and mRNA expression of genes involved in iron influx ... [more ▼]

The effects of changes in macrophage iron status, induced by single or multiple iron injections, iron depletion or pregnancy, on both immune function and mRNA expression of genes involved in iron influx and egress have been evaluated. Macrophages isolated from iron deficient rats, or pregnant rats at day 21 of gestation, either supplemented with a single dose of iron dextran, 10 mg, at the commencement of pregnancy, or not, showed significant increases of macrophage ferroportin mRNA expression, which was paralleled by significant decreases in hepatic Hamp mRNA expression. IRP activity in macrophages was not significantly altered by iron status or the inducement of pregnancy +/- a single iron supplement. Macrophage immune function was significantly altered by iron supplementation and pregnancy. Iron supplementation, alone or combined with pregnancy, increased the activities of both NADPH oxidase and nuclear factor kappa B (NFkappaB). In contrast, the imposition of pregnancy reduced the ability of these parameters to respond to an inflammatory stimuli. Increasing iron status, if only marginally, will reduce the ability of macrophages to mount a sustained response to inflammation as well as altering iron homeostatic mechanisms. [less ▲]

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See detailL’édition à l’heure du numérique
Habrand, Tanguy ULg

Article for general public (2009)

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See detailLuc Pire sans Luc Pire
Habrand, Tanguy ULg

Article for general public (2009)

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See detailMeasuring Total Electron Content with GNSS: Investigation of Two Different Techniques
Bidaine, Benoît ULg; Warnant, René ULg

in The Institution of Engineering and Technology 11th International Conference on Ionospheric Radio Systems and Techniques (IRST 2009) (2009, April)

The ionosphere widely affects Global Navigation Satellite Systems (GNSS) applications, inducing among others a delay in GNSS measurements. This delay is closely linked to the Total Electron Content (TEC ... [more ▼]

The ionosphere widely affects Global Navigation Satellite Systems (GNSS) applications, inducing among others a delay in GNSS measurements. This delay is closely linked to the Total Electron Content (TEC) of the ionosphere, a major parameter which can hence be monitored using GNSS. To this extent, phase measurements are taken as a basis for their lower noise level. Levelling strategies have then to be defined for the phase measurements are obtained with an initial unknown number of cycles called ambiguity. The most common technique, referred to as carrier-to-code levelling, consists in using the differences between code and phase measurements and their average on a continuous set of epochs. This option, chosen at the Royal Meteorological Institute (RMI) of Belgium to compute TEC for Belgian GPS stations, requires code hardware delays estimation. Another has been proposed which takes benefit from Global Ionospheric Maps (GIMs) to compute a reference TEC used for ambiguity resolution. In order to understand the consequences of using one method or the other, we compare slant TEC data obtained from both techniques for a mid-latitude station (Brussels) during a high solar activity period (2002). We observed large differences (6.8 TECu on average) showing features apparently related to ionospheric and geomagnetic activity. We attribute these observations to a combination of effects originating in code delays estimation, multipath and noise as well as GIMs errors. We try to differentiate between these effects by focusing on several days and satellites. We concentrate for example on days presenting large TEC differences and geomagnetic disturbances simultaneously (or not) or on satellites displaying recurrent patterns on consecutive days. Finally we highlight the impact of the choice of GIMs involved in sTEC calibration. To this extent, we analyse vertical TEC statistics showing a general underestimation from RMI data. The highest bias (5.8 TECu) is obtained for the UPC GIMs used in the second levelling technique. [less ▲]

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See detailEffects of ionospheric small-scale structures on GNSS
Wautelet, Gilles ULg; Lejeune, Sandrine; Warnant, René ULg

in The Institution of Engineering and Technology 11th International Conference on Ionospheric Radio Systems and Techniques (IRST 2009) (2009, April)

Nowadays, Global Navigation Satellite Systems or GNSS allow to measure positions in real-time with an accuracy ranging from a few meters to a few centimeters mainly depending on the type of observable ... [more ▼]

Nowadays, Global Navigation Satellite Systems or GNSS allow to measure positions in real-time with an accuracy ranging from a few meters to a few centimeters mainly depending on the type of observable (code or phase measurements) and on the positioning mode used (absolute or differential). The best precisions can be reached in differential mode using phase measurements. In differential mode, mobile users improve their positioning precision thanks to so-called “differential corrections” provided by a fixed reference station. For example, the Real-Time Kinematic technique (RTK) allows to measure positions in real-time with a precision usually better than a decimeter. In practice, the ionospheric effects on GNSS radio signals remain the main factor which limits the precision and the reliability of real-time differential positioning. As differential applications are based on the assumption that the measurements made by the reference station and by the mobile user are affected in the same way by ionospheric effects, these applications are influenced by gradients in TEC between the reference station and the user. For this reason, local variability in the ionospheric plasma can be the origin of strong degradations in positioning precision. In this paper, we characterize local variability in the ionosphere which can pose a threat to high precision real-time differential positioning. GNSS carrier phase measurements can be used to monitor local TEC variability: small-scale ionospheric structures can be detected by monitoring TEC high frequency changes at a single station; as ionospheric disturbances are moving, we can expect that such structures will induce TEC temporal variability which can be detected at a single station. We applied this method (called the “one-station” method) to the GPS data collected at the permanent (mid-latitude) station of Brussels from 1994 to 2007 and performed a climatological study of the ionospheric structures on this period which covers more than one solar cycle. Two main types of structures have been observed: Traveling Ionospheric Disturbances (TID’s) and “noise-like” structures. TID’s have strong seasonal and solar cycle dependence when noise-like structures are “ionospheric variability” which is usually observed during geomagnetic storms. The largest Rate of TEC (RoTEC) detected at Brussels during the period considered in our study were observed during severe geomagnetic storms. Moreover, we found that strong irregularities occur even during solar minimum. This means that, even during periods where the probability of occurrence of ionospheric irregularities is very low, large RoTEC can occur. The one-station method allows to measure variability in time but GNSS differential applications are affected by variability in space between the user and the reference station. Therefore, in a second step, we measured TEC differential variability (using double differences of phase measurements) during few typical ionospheric conditions: quiet ionospheric activity, medium and large amplitude TID’s and noise-like variability due to a severe geomagnetic storm. We also analyzed the effects of the baseline length and orientation on the residual ionospheric term. As a last step, we developed a software which reproduces positioning conditions experienced by RTK users on the field. We used this software to assess positioning errors due to the different ionospheric conditions considered in the previous step. Again, the largest effects were observed during the occurrence of geomagnetic storms. [less ▲]

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