References of "Moonen, Gustave"
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See detailNeural and cognitive bases of upper limb apraxia in corticobasal degeneration
Peigneux, Philippe ULg; Salmon, Eric ULg; Garraux, Gaëtan ULg et al

in Neurology (2001), 57(7), 1259-1268

OBJECTIVE: To investigate the neural and cognitive bases of upper limb apraxia in corticobasal degeneration (CBD). METHODS: Eighteen patients with CBD underwent a cognitive neuropsychological assessment ... [more ▼]

OBJECTIVE: To investigate the neural and cognitive bases of upper limb apraxia in corticobasal degeneration (CBD). METHODS: Eighteen patients with CBD underwent a cognitive neuropsychological assessment of apraxia and resting [(18)F]-fluorodeoxyglucose PET scanning. Two complementary measures of apraxia were computed for each modality of gesture production. First, a performance score measured error frequency during gesture execution. Second, as a more stringent test of the integrity of the praxis system, the correction score measured the patient's ability to correct his or her errors on a second attempt. For each measure type, a cut-off score for the presence of apraxia was defined with regard to healthy controls. Using each cut-off score, the regional cerebral glucose metabolism of patients with CBD with apraxia (i.e., performing below cut-off score) was compared with that of patients with CBD without apraxia. RESULTS: Mean performance scores were below normal values in all modalities. Anterior cingulate hypometabolism predominated in patients with CBD who performed below the cut-off performance score. At variance, mean correction scores were below normal values for gesture imitation only. Hypometabolism in superior parietal lobule and supplementary motor area characterized patients with CBD who were unable to correct their errors at the same rate as control subjects did. CONCLUSIONS: Distinct neural networks underlie distinct aspects of the upper limb apraxic deficits in CBD. Extending previous findings of gesture production deficits in CBD, the use of complementary measures of apraxic behavior discloses a visuoimitative upper limb apraxia in CBD, underlain by a metabolic decrease in a parietofrontal neural network. [less ▲]

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See detailNeurotransmitters as Early Signals for Central Nervous System Development
Nguyen, Laurent ULg; Rigo, Jean-Michel; Rocher, Véronique et al

in Cell & Tissue Research (2001), 305(2), 187-202

During brain ontogenesis, the temporal and spatial generation of the different types of neuronal and glial cells from precursors occurs as a sequence of successive progenitor stages whose proliferation ... [more ▼]

During brain ontogenesis, the temporal and spatial generation of the different types of neuronal and glial cells from precursors occurs as a sequence of successive progenitor stages whose proliferation, survival and cell-fate choice are controlled by environmental and cellular regulatory molecules. Neurotransmitters belong to the chemical microenvironment of neural cells, even at the earliest stages of brain development. It is now established that specific neurotransmitter receptors are present on progenitor cells of the developing central nervous system and could play, during neural development, a role that has remained unsuspected until recently. The present review focuses on the occurrence of neurotransmitters and their corresponding ligand-gated ion channel receptors in immature cells, including neural stem cells of specific embryonic and neonatal brain regions. We summarize in vitro and in vivo data arguing that neurotransmitters could regulate morphogenetic events such as proliferation, growth, migration, differentiation and survival of neural precursor cells. The understanding of neurotransmitter function during early neural maturation could lead to the development of pharmacological tools aimed at improving adult brain repair strategies. [less ▲]

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See detailLe cas clinique du mois. A propos d'un cas de syndrome des antiphospholipides
Fumal, Arnaud ULg; Belachew, Shibeshih ULg; Moonen, Gustave ULg et al

in Revue Médicale de Liège (2001), 56(7), 480-3

This article reports a case of Anton-Babinski syndrome, due to right middle cerebral artery thrombosis and attributed to a likely primary antiphospholipid syndrome. It is always difficult to diagnose the ... [more ▼]

This article reports a case of Anton-Babinski syndrome, due to right middle cerebral artery thrombosis and attributed to a likely primary antiphospholipid syndrome. It is always difficult to diagnose the latter, especially in the case of our patient who had a past history of multiple venous thromboses but also a heterozygosity for the mutation of the factor V of Leyden. We reviewed the literature dedicated to the prothrombotic events linked to the presence of these antiphospholipid antibodies: the lupus anticoagulant and the anticardiolipin antibodies. [less ▲]

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See detailPoly(D,L-lactide) foams modified by poly(ethylene oxide)-block-poly(D,L-lactide) copolymers and a-FGF: in vitro and in vivo evaluation for spinal cord regeneration
Maquet, Véronique; Martin, Didier ULg; Scholtes, Félix ULg et al

in Biomaterials (2001), 22(10), 1137-1146

The first goal of this study was to examine the influence that poly(ethylene oxide)-block-poly(D,L-lactide) (PELA) copolymer can have on the wettability, the in vitro controlled delivery capability, and ... [more ▼]

The first goal of this study was to examine the influence that poly(ethylene oxide)-block-poly(D,L-lactide) (PELA) copolymer can have on the wettability, the in vitro controlled delivery capability, and the degradation of poly(D,L-lactide) (PDLLA) foams. These foams were prepared by freeze-drying and contain micropores (10 μm) in addition of macropores (100 μm) organized longitudinally. Weight loss, water absorption, changes in molecular weight, polymolecularity (Mw/Mn) and glass transition temperature ( Tg) of PDLLA foams mixed with various amounts of PELA were followed with time. It was found that 10 wt% of PELA increased the wettability and the degradation rate of the polymer foams. The release of sulforhodamine (SR) was compared for PDLLA and PDLLA-PELA foams in relation with the foam porosity. An initial burst release was observed only in the case of the 90:10 PDLLA/PELA foam. The ability of the foam of this composition to be integrated and to promote tissue repair and axonal regeneration in the transected rat spinal cord was investigated. After implantation of ca. 20 polymer rods assembled with fibrin-glue, the polymer construct was able to bridge the cord stumps by forming a permissive support for cellular migration, angiogenesis and axonal regrowth. [less ▲]

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See detailL'image du mois. Une thrombose veineuse cerebrale
Garraux, Gaëtan ULg; Sadzot, Bernard ULg; Flandroy, Pierre et al

in Revue Médicale de Liège (2001), 56(2), 61-2

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See detailSupernumerary outer hair cells arise external to the last row of sensory cells in the organ of corti.
Lefèbvre, Philippe ULg; Malgrange, Brigitte ULg; Thiry, Marc ULg et al

in Acta Oto-Laryngologica (2001), 121(2), 164-8

During the development of the mammalian inner ear, the number of hair cells produced is highly regulated and remains constant throughout life. The mechanism underlying this regulation is beginning to be ... [more ▼]

During the development of the mammalian inner ear, the number of hair cells produced is highly regulated and remains constant throughout life. The mechanism underlying this regulation is beginning to be understood although many aspects still remain obscure. When late embryonic or early postnatal rat organs of Corti were cultured, the production of supernumerary hair cells was observed. This overproduction of sensory cells could be modulated by the addition of several growth factors. In this study, we examined explants of rat organs of Corti that produced supernumerary hair cells. In the supernumerary hair cell region, up to two rows of inner hair cells and five rows of outer hair cells were observed. Morphological evaluation of these specimens revealed that less mature hair cells were located in the most external rows of these sensory cells. When a supernumerary hair cell was produced, a supporting cell (i.e. Deiters' cell) was also produced, strongly suggesting that the conversion of a Deiters' cell into a hair cell was not the mechanism that produced these extra hair cells. Based on these results, we propose that prosensory cells located at the external edge of the organ of Corti retain a capacity to form hair cells and that it is these prosensory cells that differentiate into supernumerary hair cells and Deiters' cells. [less ▲]

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See detailHensen's cells acquire specific hair cell markers in vitro, strengthening their role as precursors of supernumerary OHCs
Lefèbvre, P; Malgrange, B; Thiry, Marc ULg et al

Conference (2001)

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See detailHensen's cells as precursors of supernumerary OHCs
Malgrange, B; Lefèbvre, P; Thiry, Marc ULg et al

Poster (2001)

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See detailPhenotypic plasticity of cerebellar radial glia
Leprince, P; Chanas-Sacré, G; Nguyen, L et al

Poster (2001)

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See detailEtudes par tomographie à émission de positons chez des patients en coma, en état végétatif ou de conscience minimale, en «locked-in syndrome» et en mort cérébrale
Laureys, Steven ULg; Faymonville, Marie-Elisabeth ULg; Berre, Jacques et al

in L'évaluation neurophysiologique des comas, de la mort encéphalique et des états végétatifs (2001)

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See detailMicroexplant cultures of the cerebellum
Rogister, Bernard ULg; Moonen, Gustave ULg

in Feoroff, Serguei; Richardson, Arleen (Eds.) Protocols for neural cell cultures (2001)

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See detailPeripheral Nerve Regeneration Using Bioresorbable Macroporous Polylactide Scaffolds
Maquet, Véronique; Martin, Didier ULg; Malgrange, Brigitte ULg et al

in Journal of Biomedical Materials Research, Part A (2000), 52(4), 639-51

The ability of DRG-derived neurons to survive and attach onto macroporous polylactide (PLA) foams was assessed in vitro. The foams were fabricated using a thermally induced polymer-solvent phase ... [more ▼]

The ability of DRG-derived neurons to survive and attach onto macroporous polylactide (PLA) foams was assessed in vitro. The foams were fabricated using a thermally induced polymer-solvent phase separation. Two types of pore structures, namely oriented or interconnected pores, can be produced, depending on the mechanism of phase separation, which in turn can be predicted by the thermodynamics of the polymer-solvent pair. Coating of the porous foams with polyvinylalcohol (PVA) considerably improved the wettability of the foams and allowed for cell culture. The in vitro biocompatibility of the PVA-coated supports was demonstrated by measuring cell viability and neuritogenesis. Microscopic observations of the cells seeded onto the polymer foams showed that the interconnected pore networks were more favorable to cell attachment than the anisotropic ones. The capacity of highly oriented foams to support in vivo peripheral nerve regeneration was studied in rats. A sciatic nerve gap of 5-mm length was bridged with a polymer implant showing macrotubes of 100 microm diameter. At 4 weeks postoperatively, the polymer implant was still present. It was well integrated and had restored an anatomic continuity. An abundant cell migration was observed at the outer surface of the polymer implant, but not within the macrotubes. This dense cellular microenvironment was found to be favorable for axogenesis. [less ▲]

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See detailA 295-Kda Intermediate Filament-Associated Protein in Radial Glia and Developing Muscle Cells in Vivo and in Vitro
Chanas-Sacre, Grazyna; Thiry, Marc ULg; Pirard, Sandrine et al

in Developmental Dynamics : An Official Publication of the American Association of Anatomists (2000), 219(4), 514-25

The RC2 antibody is frequently used to label mouse radial glial cells in all parts of the nervous system where neuronal migration occurs during embryonic and early postnatal life. The antigen recognized ... [more ▼]

The RC2 antibody is frequently used to label mouse radial glial cells in all parts of the nervous system where neuronal migration occurs during embryonic and early postnatal life. The antigen recognized by this antibody still needs to be identified. We have characterized further its localization in vivo, its expression and subcellular localization in vitro, as well as its molecular nature. Histologic investigations of whole mouse embryos reveal an equally intense expression of RC2 immunostaining in radial glial cells in brain and spinal cord and in skeletal muscle. In glial cells cultures, the RC2 antibody recognizes an epitope located on the glial cytoskeleton and identified as an intermediate filament associated protein (IFAP) at the ultrastructural level. RC2 immunostaining in those cells is strongly dependent on the presence of a serum-derived activity. Serum-removal causes a decrease of the staining while adding serum back to the cells induces reexpression of RC2 immunoreactivity. By Western blotting, we find that in intermediate filament (IF) preparations obtained from cultured cerebellar glia, the RC2 antibody recognizes a 295-kDa protein whose expression is also dependent on the presence of serum in culture medium. In developing muscle cells, RC2 immunostaining is observed from the myoblast stage and disappears after complete myotube fusion. Both in vivo and in vitro, staining is first seen as a loose capping around myoblasts nuclei and progressively concentrates into Z-disks in association with the muscle IF protein desmin. The RC2 antibody also recognizes a 295-kDa protein band in muscle tissue protein extracts. Thus, the RC2 antibody recognizes a developmentally regulated cytoskeletal protein that is expressed, like other previously identified IFAPs, by cells of the glial and myogenic lineages and whose expression in vitro seems to be controlled by a signaling mechanism known to modulate astroglial morphology. [less ▲]

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See detailRadial Glia Phenotype: Origin, Regulation, and Transdifferentiation
Chanas-Sacre, Grazyna; Rogister, Bernard ULg; Moonen, Gustave ULg et al

in Journal of Neuroscience Research (2000), 61(4), 357-63

Radial glial cells play a major guidance role for migrating neurons during central nervous system (CNS) histogenesis but also play many other crucial roles in early brain development. Being among the ... [more ▼]

Radial glial cells play a major guidance role for migrating neurons during central nervous system (CNS) histogenesis but also play many other crucial roles in early brain development. Being among the earliest cells to differentiate in the early CNS, they provide support for neuronal migration during embryonic brain development; provide instructive and neurotrophic signals required for the survival, proliferation, and differentiation of neurons; and may be multipotential progenitor cells that give rise to various cell types, including neurons. Radial glial cells constitute a major cell type of the developing brain in numerous nonmammalian and mammalian vertebrates, increasing in complexity in parallel with the organization of the nervous tissue they help to build. In mammalian species, these cells transdifferentiate into astrocytes when neuronal migration is completed, whereas, in nonmammalian species, they persist into adulthood as a radial component of astroglia. Thus, our perception of radial glia may have to change from that of path-defining cells to that of specialized precursor cells transiently fulfilling a guidance role during brain histogenesis. In that respect, their apparent change of phenotype from radial fiber to astrocyte probably constitutes one of the most common transdifferentiation events in mammalian development. [less ▲]

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See detailPharmacological Modulation of the Bystander Effect in the Herpes Simplex Virus Thymidine Kinase/Ganciclovir Gene Therapy System: Effects of Dibutyryl Adenosine 3',5'-Cyclic Monophosphate, Alpha-Glycyrrhetinic Acid, and Cytosine Arabinoside
Robe, Pierre ULg; Princen, Frédéric; Martin, Didier ULg et al

in Biochemical Pharmacology (2000), 60(2), 241-9

The herpes simplex virus type 1 thymidine kinase (HSV1-tk) suicide gene/ganciclovir system was first applied to the treatment of glioblastoma tumors, but was hampered by the low gene transfection yield ... [more ▼]

The herpes simplex virus type 1 thymidine kinase (HSV1-tk) suicide gene/ganciclovir system was first applied to the treatment of glioblastoma tumors, but was hampered by the low gene transfection yield. Fortunately, the gap junction-dependent diffusion of phosphorylated ganciclovir metabolites from transfected cells to their neighbors proved to enhance the overall benefit of this strategy. However, as tumor cells are often gap junction-deficient, we sought to restore this property pharmacologically and hence to improve the efficacy of the treatment. We demonstrated that this approach was feasible in glioblastoma cells using dibutyryl adenosine 3',5'-cyclic monophosphate (cAMP) (100 microM) as a pharmacological inducer of gap junctions. alpha-Glycyrrhetinic acid (25 microM), on the other hand, strongly inhibited both gap junction-mediated intercellular communication and the bystander effect, thus confirming the role of gap junctions in HSV-tk-mediated bystander killing. Using cytosine arabinoside as a growth inhibitor, we underlined the role of tumor cell proliferation in the sensitivity of HSV-tk-transfected cells to ganciclovir and demonstrated its correlation with the importance of the bystander effect. [less ▲]

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See detailGlycine Triggers an Intracellular Calcium Influx in Oligodendrocyte Progenitor Cells Which Is Mediated by the Activation of Both the Ionotropic Glycine Receptor and Na+-Dependent Transporters
Belachew, Shibeshih ULg; Malgrange, Brigitte ULg; Rigo, Jean-Michel et al

in European Journal of Neuroscience (2000), 12(6), 1924-30

Using fluo-3 calcium imaging, we demonstrate that glycine induces an increase in intracellular calcium concentration ([Ca2+]i) in cortical oligodendrocyte progenitor (OP) cells. This effect results from a ... [more ▼]

Using fluo-3 calcium imaging, we demonstrate that glycine induces an increase in intracellular calcium concentration ([Ca2+]i) in cortical oligodendrocyte progenitor (OP) cells. This effect results from a calcium entry through voltage-gated calcium channels (VGCC), as it is observed only in OP cells expressing such channels, and it is abolished either by removal of calcium from the extracellular medium or by application of an L-type VGCC blocker. Glycine-triggered Ca2+ influx in OP cells actually results from an initial depolarization that is the consequence of the activation of both the ionotropic glycine receptor (GlyR) and Na+-dependent transporters, most probably the glycine transporters 1 (GLYT1) and/or 2 (GLYT2) which are colocalized in these cells. Through this GlyR- and transporter-mediated effect on OP intrcellular calcium concentration [Ca2+]i, glycine released by neurons may, as well as other neurotransmitters, serve as a signal between neurons and OP during development. [less ▲]

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See detailEpidermal Growth Factor Upregulates Production of Supernumerary Hair Cells in Neonatal Rat Organ of Corti Explants
Lefèbvre, Philippe ULg; Malgrange, Brigitte ULg; Thiry, Marc ULg et al

in Acta Oto-Laryngologica (2000), 120(2), 142-5

The organ of Corti is highly ordered, with a single row of inner hair cells and three rows of outer hair cells. The number of hair cells produced was thought to be limited by the time of their terminal ... [more ▼]

The organ of Corti is highly ordered, with a single row of inner hair cells and three rows of outer hair cells. The number of hair cells produced was thought to be limited by the time of their terminal mitosis (i.e. E14 in the mouse). However, exogenous application of retinoic acid has been shown to stimulate the formation of supernumerary hair cells in organ of Corti explants from E13 to E16 mouse embryos. Using late embryonic and neonatal rat organ of Corti explants, we investigated the potential for production of supernumerary hair cells in more mature auditory sensory epithelia. When newborn rat organ of Corti explants were cultured under control conditions, an area of supernumerary hair cells was observed in a segment of organ of Corti that was at the junction between the basal and middle turns. In these areas of supernumerary hair cells the number of hair cells increased per unit of length, but remained constant per surface unit, further demonstrating the supernumerary character of this phenomenon. Organ of Corti explants treated with epidermal growth factor (EGF) showed a 50% increase in the length of the organ of Corti segment containing supernumerary hair cells. Upregulation of supernumerary hair cell formation by EGF was found to start and be maximal at birth (P0) and to disappear by 2 days after birth (P2). Treatment of EGF stimulated P0 explants with an antimitotic drug, cytosine arabinoside (ARAc), demonstrated that the production of supernumerary hair cells occurred independently of cell division. [less ▲]

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See detailSupernumerary outer hair cells arise external to the last row of sensory cells in the neonatal organ of Corti
Lefèbvre, P; Malgrange, B; Thiry, Marc ULg et al

Conference (2000)

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See detailThe radial glial cell antigen recognized by the RC2 antibody: characterization and modulation in vitro of its expression
Chanas-Sacré, G; Thiry, Marc ULg; Rogister, B et al

in Revista de Neurologia (2000), 24

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