References of "Blacher, Silvia"
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See detailRestricted expression of membrane type 1-matrix metalloproteinase by myofibroblasts adjacent to human breast cancer cells
Bisson, C.; Blacher, Silvia ULg; Polette, M. et al

in International Journal of Cancer = Journal International du Cancer (2003), 105(1), 7-13

The membrane type-1 matrix metalloproteinase (MT1-MMP), a protease originally identified in breast carcinoma, is characterized by its capacity to activate other MMPs (MMP-2 and MMP-13) and to degrade ... [more ▼]

The membrane type-1 matrix metalloproteinase (MT1-MMP), a protease originally identified in breast carcinoma, is characterized by its capacity to activate other MMPs (MMP-2 and MMP-13) and to degrade extracellular matrix. Our study was undertaken to localize and identify the MT1-MMP expressing cells in human breast adenocarcinomas. A textural analysis of images obtained by immunohistochemistry and in situ hybridization showed precisely the co-expression of alpha smooth muscle actin (alphaSM actin) and MT1-MMP in myofibroblasts. MT1-MMP expression is confined to myofibroblasts in close contact with tumor cells. In sharp contrast, the expression of MMP-2 was more widely distributed in both alphaSM actin positive and negative cells close to and at distance from cancer cell clusters. Our in vitro observations are consistent with the higher level of MT1-MMP expression and of MMP-2 activation observed in alphaSM actin positive fibroblasts derived from breast tumors, as compared to normal breast fibroblasts. Collectively, these results implicate myofibroblasts as major producer of MT1-MMP in breast cancer and emphasize the importance of stromal-epithelial cell interactions in their progression. [less ▲]

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See detailImage analysis of the axonal ingrowth into poly(D,L-lactide) porous scaffolds in relation to the 3-D porous structure
Blacher, Silvia ULg; Maquet, Véronique; Luyckx, Françoise ULg et al

in Biomaterials (2003), 24(6), 1033-1040

Porous polymer scaffolds are promising materials for neural tissue engineering because they offer valuable three-dimensional (3D) supports for the in vitro and in vivo axonal growth and tissue expansion ... [more ▼]

Porous polymer scaffolds are promising materials for neural tissue engineering because they offer valuable three-dimensional (3D) supports for the in vitro and in vivo axonal growth and tissue expansion. At the time being, how the in vivo neuronal cell development depends on the scaffold 3-D architecture is unknown. Therefore, scanning electron micrographs of longitudinal sections of porous polylactide scaffolds and immunohistological sections of these scaffolds after implantation and neurofilament staining have been studied by image analysis. Pore orientation and axonal ingrowth have been investigated by spectral analysis on gray level SEM images. Binary image processing has been carried out and the binary images have been studied by spectral analysis in order to estimate the possible effect of the image noise on the real pattern. In addition to axonal orientation, density and length distribution of the regenerated axons into the polymer scaffold have been measured. Dependence of the axonal ingrowth on the 3D-polymer scaffold has been discussed on the basis of the collected data. (C) 2002 Elsevier Science Ltd. All rights reserved. [less ▲]

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See detailStabilization of a cocontinuous phase morphology by a tapered diblock or triblock copolymer in polystyrene-rich low-density polvethylene/polstyrene blends
Harrats, Charef; Fayt, Roger; Jérôme, Robert ULg et al

in Journal of Polymer Science. Part B, Polymer Physics (2003), 41(2), 202-216

The stability against the thermal annealing of a cocontinuous two-phase morphology developed in polystyrene (PS)/low-density polyethylene (LDPE) blends containing 80 wt % PS was investigated. Blends ... [more ▼]

The stability against the thermal annealing of a cocontinuous two-phase morphology developed in polystyrene (PS)/low-density polyethylene (LDPE) blends containing 80 wt % PS was investigated. Blends containing 1, 5, and 10 wt % of a tapered diblock poly(styrene-block-hydrogenated butadiene) (P(S-b-hB)) or triblock poly(styrene-block-hydrogenated butadiene-block-styrene) (P(S-hB-S)) copolymer were melt-blended with roll-mill mixing equipment. The efficiency of each of the two copolymers in stabilizing against coalescence the cocontinuous morphology was examined. The tensile properties of the resulting blends, annealed and nonannealed, were also examined in relation to the morphology induced by thermal annealing. The phase morphology was studied by optical and scanning electron microscopy. With computer-aided image analysis, it was possible to obtain a measurable characteristic parameter to quantify the cocontinuous phase morphology. When it was necessary, the extraction of one phase with a selective solvent was performed. Although the observed differences were subtle, the tapered diblock exhibited a more efficient compatibilizing activity than the triblock copolymer, particularly at a low concentration of about 2 wt %. The superiority of the tapered diblock over the triblock might be due to its ability to quantitatively locate at the LDPE/PS interface and consequently form a more efficient barrier against the subsequent breakup of the elongated structures of the cocontinuous phase morphology. The tensile properties of the triblock-modified blends were more sensitive to thermal annealing than the tapered-modified ones. This deficiency was ascribed to the phase morphology coarsening of the dispersed polyethylene phase. [less ▲]

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See detailHydrodynamique et morphologie d'une bactérie filamenteuse dans un fermenteur à cuve agitée
Groslambert, Sylvie ULg; Blacher, Silvia ULg; Crine, Michel ULg

in Tribune de l'Eau (La) (2003), 56(622), 58-64

Afin d'étudier l'influence de l'hydrodynamique sur une bactérie filamenteuse, Actinomadura R39, nous l'avons cultivée dans un fermenteur de laboratoire de 5 litres à cuve agitée en faisant varier les ... [more ▼]

Afin d'étudier l'influence de l'hydrodynamique sur une bactérie filamenteuse, Actinomadura R39, nous l'avons cultivée dans un fermenteur de laboratoire de 5 litres à cuve agitée en faisant varier les conditions d'agitation. Les variables sont la vitesse de rotation et le type de mobile utilisé: turbines Rushton ou Intermig. Les deux mobiles se distinguent par leur géométrie et par les schémas d'écoulement qu'ils induisent dans la cuve. L'influence de l'hydrodynamique sur Actinomadura R39 est quantifiée par l'évolution de sa morphologie. Cette dernière est estimée par analyse d'images sur des échantillons prélevés lors des cultures. Parallèlement, nous avons caractérisé l'hydrodynamique du fermenteur dans un milieu artificiel reproduisant la rhéologie des fermentations en mesurant la puissance dissipée et en effectuant des essais de traceurs. Ces derniers sont utilisés pour la modélisation du fermenteur par un modèle compartimenté et le calcul du temps de mélange. Nous avons pu ainsi mettre en relation les modifications de la morphologie et des grandeurs caractérisant les écoulements dans le fermenteur. L'existence de corrélations entre les paramètres du modèle et la morphologie a également permis une validation de la signification physique de ce modèle. [less ▲]

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See detailQuantification of Angiogenesis of Embryonic Implantation Site by Image Analysis
Le Maire, Sophie; Blacher, Silvia ULg; Frankenne, F. et al

Conference (2003)

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See detailMultiscale texture characterization of wastewater sludges dried in a convective rig
Léonard, Angélique ULg; Blacher, Silvia ULg; Pirard, René ULg et al

in Drying Technology (2003), 21(8), 1507-1526

Secondary sludges from two different wastewater treatment plants are conditioned and dewatered in the same way before drying in a lab-scale convective rig at the same operating conditions. Several ... [more ▼]

Secondary sludges from two different wastewater treatment plants are conditioned and dewatered in the same way before drying in a lab-scale convective rig at the same operating conditions. Several techniques are used to characterize the texture of the dried materials over a wide range of scales from nm up to mm. Texture and porosity of the dried products are studied by SEM imaging, nitrogen absorption isotherms (0.5 < d(p) < 50 nm), mercury porosimetry (7.5 nm < d(p) < 150 mum) and X-ray microtomography (spatial resolution= 41 mum). The image analysis of cross-sections reconstructed by microtomography also allows following shrinkage and textural evolution during drying. [less ▲]

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See detailImage analysis characterization of multi-walled carbon nanotubes
Gommes, Cédric ULg; Blacher, Silvia ULg; Masenelli-Varlot, Karine et al

in Carbon (2003), 41(13), 2561-2572

An original image analysis method is presented to characterize multi-walled carbon nanotubes from transmission electron microscopy images. The analysis is performed in three steps: (i) image preprocessing ... [more ▼]

An original image analysis method is presented to characterize multi-walled carbon nanotubes from transmission electron microscopy images. The analysis is performed in three steps: (i) image preprocessing in order to isolate the nanotubes from the background, (ii) image segmentation, aiming at keeping only the measurable sections of nanotubes, and finally (iii) tube characteristics measurement. The measurement is based on a Lambert-like electron absorption law and is performed on the original gray level image itself. Two geometrical and one physical characteristics are determined for each tube, namely, its outer and inner radius and a linear electron absorption coefficient. The method is illustrated by comparing a pristine and an annealed carbon nanotube samples. The compaction of the tube walls during annealing is shown to result from a lowering of the external radius while the inner radius is left unchanged. (C) 2003 Elsevier Ltd. All rights reserved. [less ▲]

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See detailQuantification of angiogenesis on the rat aortic ring assay.
Blacher, Silvia ULg; Devy, L.; Noël, Agnès ULg et al

in Image Analysis and Stereology (2003), 22

Image analysis is used to quantify angiogenesis on the rat aortic ring model. This technique allows to determine: (1) the aortic ring area and factor shape; (2) the number of microvessels, the total ... [more ▼]

Image analysis is used to quantify angiogenesis on the rat aortic ring model. This technique allows to determine: (1) the aortic ring area and factor shape; (2) the number of microvessels, the total number of branching, the maximal microvessel length and the number of microvessels in function of the distance to the aortic ring; (3) the total number of isolated fibroblast-like cells and the number of fibroblast-like cells in function of the distance to the aortic ring. We show that this method is suitable to quantify spontaneous angiogenesis as well as to analyse a complex microvascular network induced by vascular endothelial growth factor (VEGF). [less ▲]

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See detailMouse Aortic Ring Assay: A New Approach of the Molecular Genetics of Angiogenesis
Masson, Véronique ULg; Devy, L.; Grignet-Debrus, Christine ULg et al

in Biological Procedures Online (2002), 4

Angiogenesis, a key step in many physiological and pathological processes, involves proteolysis of the extracellular matrix. To study the role of two enzymatic families, serine-proteases and matrix ... [more ▼]

Angiogenesis, a key step in many physiological and pathological processes, involves proteolysis of the extracellular matrix. To study the role of two enzymatic families, serine-proteases and matrix metalloproteases in angiogenesis, we have adapted to the mouse, the aortic ring assay initially developed in the rat. The use of deficient mice allowed us to demonstrate that PAI-1 is essential for angiogenesis while the absence of an MMP, MMP-11, did not affect vessel sprouting. We report here that this model is attractive to elucidate the cellular and molecular mechanisms of angiogenesis, to identify, characterise or screen "pro- or anti-angiogenic agents that could be used for the treatment of angiogenesis-dependent diseases. Approaches include using recombinant proteins, synthetic molecules and adenovirus-mediated gene transfer. [less ▲]

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See detailTexture characterisation of ultramacroporous materials using non-destructive methods
Blacher, Silvia ULg; Maquet, Véronique; Léonard, Angélique ULg et al

Conference (2002, May)

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See detailMulti-walled nanotubes diameter distribution by image analysis
Gommes, Cédric ULg; BLACHER, Silvia ULg; Bossuot, Christophe ULg et al

Scientific conference (2002, February)

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See detailThe pro- or antiangiogenic effect of plasminogen activator inhibitor 1 is dose dependent
Devy, L.; Blacher, Silvia ULg; Grignet-Debrus, Christine ULg et al

in FASEB Journal (2002), 16(2), 147-54

Plasminogen activator inhibitor 1 (PAI-1) is believed to control proteolytic activity and cell migration during angiogenesis. We previously demonstrated in vivo that this inhibitor is necessary for ... [more ▼]

Plasminogen activator inhibitor 1 (PAI-1) is believed to control proteolytic activity and cell migration during angiogenesis. We previously demonstrated in vivo that this inhibitor is necessary for optimal tumor invasion and vascularization. We also showed that PAI-1 angiogenic activity is associated with its control of plasminogen activation but not with the regulation of cell-matrix interaction. To dissect the role of the various components of the plasminogen activation system during angiogenesis, we have adapted the aortic ring assay to use vessels from gene-inactivated mice. The single deficiency of tPA, uPA, or uPAR, as well as combined deficiencies of uPA and tPA, did not dramatically affect microvessel formation. Deficiency of plasminogen delayed microvessel outgrowth. Lack of PAI-1 completely abolished angiogenesis, demonstrating its importance in the control of plasmin-mediated proteolysis. Microvessel outgrowth from PAI-1(-/-) aortic rings could be restored by adding exogenous PAI-1 (wild-type serum or purified recombinant PAI-1). Addition of recombinant PAI-1 led to a bell-shaped angiogenic response clearly showing that PAI-1 is proangiogenic at physiological concentrations and antiangiogenic at higher levels. Using specific PAI-1 mutants, we could demonstrate that PAI-1 promotes angiogenesis at physiological (nanomolar) concentrations through its antiproteolytic activity rather than by interacting with vitronectin. [less ▲]

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See detailHistone deacetylases inhibitors as anti-angiogenic agents altering vascular endothelial growth factor signaling
Deroanne, Christophe ULg; Bonjean, Karine; Servotte, Sandrine et al

in Oncogene (2002), 21(3), 427-436

Angiogenesis is a complex biological process involving the coordinated modulation of many genes. Histone deacetylases (HDAC) are a growing family of enzymes that mediate the availability of chromatin to ... [more ▼]

Angiogenesis is a complex biological process involving the coordinated modulation of many genes. Histone deacetylases (HDAC) are a growing family of enzymes that mediate the availability of chromatin to the transcriptional machinery. Trichostatin-A (TSA) and suberoylanilide hydroxamic acid (SAHA), two HDAC inhibitors known to relieve gene silencing, were evaluated as potential antiangiogenic agents. TSA and SAHA were shown to prevent vascular endothelial growth factor (VEGF)-stimulated human umbilical cord endothelial cells (HUVEC) from invading a type I collagen gel and forming capillary-like structures. SAHA and TSA inhibited the VEGF-induced formation of a CD31-positive capillary-like network in embryoid bodies and inhibited the VEGF-induced angiogenesis in the CAM assay. TSA also prevented, in a dose-response relationship, the sprouting of capillaries from rat aortic rings. TSA inhibited in a dose-dependent and reversible fashion the VEGF-induced expression of VEGF receptors, VEGFR1, VEGFR2, and neuropilin-1. TSA and SAHA upregulated the expression by HUVEC of semaphorin III, a recently described VEGF competitor, at both mRNA and protein levels. This effect was specific to endothelial cells and was not observed in human fibroblasts neither in vascular smooth muscle cells. These observations provide a conspicuous demonstration that HDAC inhibitors are potent anti-angiogenic factors altering VEGF signaling. [less ▲]

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See detailImage analysis characterization of highly oriented freeze-drying porous materials
Blacher, Silvia ULg; Maquet, Véronique; Jérôme, Robert ULg et al

in Image Analysis and Stereology (2002), 21

Image analysis has been used as a potential tool for the characterization of the texture of ultramacroporous foams prepared by freeze-drying. It has been shown that this technique actually provides ... [more ▼]

Image analysis has been used as a potential tool for the characterization of the texture of ultramacroporous foams prepared by freeze-drying. It has been shown that this technique actually provides valuable information on the structure of this kind of material. Image analysis of SEM micrographs of transverse sections at two different magnifications gave information on both the macroporosity (10 μm < width < 100 μm) and ultramacroporosity (width > 100 μm). Moreover, the foam anisotropy has been determined by image analysis of longitudinal sections. [less ▲]

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