References of "Moonen, Gustave"
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See detailCdk2 Is Dispensable for Adult Hippocampal Neurogenesis
Vandenbosch, Renaud ULg; Borgs, Laurence ULg; Beukelaers, Pierre ULg et al

in Cell Cycle (Georgetown, Tex.) (2007), 6(24), 3065-9

Granule neurons of the dentate gyrus (DG) of the hippocampus undergo continuous renewal throughout life. Among cell cycle regulators, cyclin-dependent kinase 2 (Cdk2) is considered as a major regulator of ... [more ▼]

Granule neurons of the dentate gyrus (DG) of the hippocampus undergo continuous renewal throughout life. Among cell cycle regulators, cyclin-dependent kinase 2 (Cdk2) is considered as a major regulator of S-phase entry. We used Cdk2-deficient mice to decipher the requirement of Cdk2 for the generation of new neurons in the adult hippocampus. The quantification of cell cycle markers first revealed that the lack of Cdk2 activity does not influence spontaneous or seizure-induced proliferation of neural progenitor cells (NPC) in the adult DG. Using bromodeoxyuridine incorporation assays, we showed that the number of mature newborn granule neurons generated de novo was similar in both wild-type (WT) and Cdk2-deficient adult mice. Moreover, the apparent lack of cell output reduction in Cdk2(-/-) mice DG did not result from a reduction in apoptosis of newborn granule cells as analyzed by TUNEL assays. Our results therefore suggest that Cdk2 is dispensable for NPC proliferation, differentiation and survival of adult-born DG granule neurons in vivo. These data emphasize that functional redundancies between Cdks also occur in the adult brain at the level of neural progenitor cell cycle regulation during hippocampal neurogenesis. [less ▲]

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See detailNew insights into peripherin expression in cochlear neurons
Lallemend, François; Vandenbosch, Renaud ULg; Hadjab, S. et al

in Neuroscience (2007), 150(1), 212-222

Peripherin is an intermediate filament protein that is expressed in peripheral and enteric neurons. In the cochlear nervous system, peripherin expression has been extensively used as a differentiation ... [more ▼]

Peripherin is an intermediate filament protein that is expressed in peripheral and enteric neurons. In the cochlear nervous system, peripherin expression has been extensively used as a differentiation marker by preferentially labeling the type II neuronal population at adulthood, but yet without knowing its function. Since the expression of peripherin has been associated in time with the process of axonal extension and during regeneration of nerve fibers in other systems, it was of interest to determine whether peripherin expression in cochlear neurons was a static phenotypic trait or rather prone to modifications following nerve injury. In the present study, we first compared the expression pattern of peripherin and beta III-tubulin from late embryonic stages to the adult in rat cochlea. The staining for both proteins was seen before birth within all cochlear neurons. By birth, and for 2 or 3 days, peripherin expression was gradually restricted to the type II neuronal population and their projections. In contrast, from postnatal day (P) 10 onwards, while the expression of beta III-tubulin was still found in projections of all cochlear neurons, only the type I population had beta III-tubulin immunoreactivity in their cell bodies. We next investigated the expression of peripherin in axotomized cochlear neurons using an organotypic explant model. Peripherin expression was surprisingly re-expressed in a vast majority of neurons after axotomy. In parallel, the expression and localization of beta III-tubulin and peripherin in dissociated cultures of cochlear neurons were studied. Both proteins were distributed along the entire neuronal length but exhibited complementary distribution, especially within the projections. Moreover, peripherin immunoreactivity was still abundant in the growth cone, whereas that of beta III-tubulin was decreasing at this compartment. Our findings are consistent with a model in which peripherin plays an important structural role in cochlear neurons and their projections during both development and regenerative processes and which is compatible with the assumption that frequently developmentally regulated factors are reactivated during neuronal regeneration. [less ▲]

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See detailNeurotransmitters regulate cell migration in the telencephalon
Heng, J. I. T.; Moonen, Gustave ULg; Nguyen, Laurent ULg

in European Journal of Neuroscience (2007), 26(3), 537-546

The complex cytoarchitectonic organization of the adult mammalian telencephalon reflects the elaborate patterns of cell migration that contribute to its generation. The migration by neurons in the CNS can ... [more ▼]

The complex cytoarchitectonic organization of the adult mammalian telencephalon reflects the elaborate patterns of cell migration that contribute to its generation. The migration by neurons in the CNS can broadly be divided into two categories: radial and tangential. Experimental observations in the telencephalon have shown that glutamatergic projection neurons are born in the progenitor compartment of the dorsal telencephalon and migrate radially to integrate the cortical plate, whereas most gamma-aminobutyric acid (GABA)ergic interneurons are generated in the ganglionic eminences and navigate through multiple tangential paths to settle into distinct telencephalic structures. Despite progress towards the understanding of the genetic determinants that specify the fate of neuronal progenitors, much remains unknown about the mechanisms that direct their migration into specific regions of the telencephalon. Interestingly, besides their function in synaptic transmission, neurotransmitters have been shown to promote several developmental processes that contribute to the establishment and maintenance of the CNS. In this respect, recent studies have highlighted a role for neurotransmitters through activation of their receptors in regulating cell migration in the telencephalon. This review summarizes and discusses the growing body of literature implicating neurotransmitters and their cognate receptors as part of a complex molecular machinery that regulate the migration of immature neurons in the telencephalon during development and in adulthood. [less ▲]

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See detailBaseline brain activity fluctuations predict somatosensory perception in humans
Boly, Mélanie ULg; Balteau, Evelyne ULg; Schnakers, Caroline ULg et al

in Proceedings of the National Academy of Sciences of the United States of America (2007), 104(29), 12187-12192

In perceptual experiments, within-individual fluctuations in perception are observed across multiple presentations of the same stimuli, a phenomenon that remains only partially understood. Here, by means ... [more ▼]

In perceptual experiments, within-individual fluctuations in perception are observed across multiple presentations of the same stimuli, a phenomenon that remains only partially understood. Here, by means of thulium-yttrium/aluminum- garnet laser and event-related functional MRI, we tested whether variability in perception of identical stimuli relates to differences in prestimulus, baseline brain activity. Results indicate a positive relationship between conscious perception of low-intensity somatosensory stimuli and immediately preceding levels of baseline activity in medial thalamus and the lateral frontoparietal network, respectively, which are thought to relate to vigilance and "external monitoring." Conversely, there was a negative correlation between subsequent reporting of conscious perception and baseline activity in a set of regions encompassing posterior cingulate/ precuneus and temporoparietal cortices, possibly relating to introspection and self-oriented processes. At nociceptive levels of stimulation, pain-intensity ratings positively correlated with baseline fluctuations in anterior cingulate cortex in an area known to be involved in the affective dimension of pain. These results suggest that baseline brain-activity fluctuations may profoundly modify our conscious perception of the external world. [less ▲]

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See detailWhen thoughts become action: An fMRI paradigm to study volitional brain activity in non-communicative brain injured patients
Boly, Mélanie ULg; Coleman, M. R.; Davis, M. H. et al

in NeuroImage (2007), 36(3), 979-992

The assessment of voluntary behavior in non-communicative brain injured patients is often challenging due to the existence of profound motor impairment. In the absence of a full understanding of the ... [more ▼]

The assessment of voluntary behavior in non-communicative brain injured patients is often challenging due to the existence of profound motor impairment. In the absence of a full understanding of the neural correlates of consciousness, even a normal activation in response to passive sensory stimulation cannot be considered as proof of the presence of awareness in these patients. In contrast, predicted activation in response to the instruction to perform a mental imagery task would provide evidence of voluntary task-dependent brain activity, and hence of consciousness, in non-communicative patients. However, no data yet exist to indicate which imagery instructions would yield reliable single subject activation. The aim of the present study was to establish such a paradigm in healthy volunteers. Two exploratory experiments evaluated the reproducibility of individual brain activation elicited by four distinct mental imagery tasks. The two most robust mental imagery tasks were found to be spatial navigation and motor imagery. In a third experiment, where these two tasks were directly compared, differentiation of each task from one another and from rest periods was assessed blindly using a priori criteria and was correct for every volunteer. The spatial navigation and motor imagery tasks described here permit the identification of volitional brain activation at the single subject level, without a motor response. Volunteer as well as patient data [Owen, A. M., Coleman, M.R., Boly, M., Davis, M.H., Laureys, S., Pickard J.D., 2006. Detecting awareness in the vegetative state. Science 313, 1402] strongly suggest that this' paradigm may provide a method for assessing the presence of volitional brain activity, and thus of consciousness, in non-communicative brain-injured patients. (c) 2007 Elsevier Inc. All rights reserved. [less ▲]

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See detailCerebral resting state fluctuations predict somatosensory perception
Boly, Mélanie ULg; Balteau, Evelyne ULg; Schnakers, Caroline ULg et al

in Journal of Neurology (2007, May), 254(Suppl. 3), 42

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See detailEffect of dementia severity and age on posterior cingulate cortex metabolism in Alzheimer's disease
Withofs, Nadia ULg; Salmon, Eric ULg; Hallet, Claude ULg et al

in Journal of Neurology (2007, May), 254(Suppl. 3), 146

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See detailLocked-in syndrome et états de conscience altérée: comment détecter la conscience?
Vanhaudenhuyse, Audrey ULg; Bruno, Marie-Aurélie ULg; Schnakers, Caroline ULg et al

in Pellas, Frederique; Kiefer, C; Weiss, JJ (Eds.) et al Eveil de coma et états limites (2007)

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See detailEvaluation comportementale et par neuroimagerie fonctionnelle des patients en état végétatif
Vanhaudenhuyse, Audrey ULg; Schnakers, Caroline ULg; Boly, Mélanie ULg et al

in Revue Médicale de Liège (2007), 62 Spec No

Currently, there remains a high rate of misdiagnosis of the vegetative state. This should incite clinicians to use the most sensitive "coma scales" to detect signs of consciousness in these patients. The ... [more ▼]

Currently, there remains a high rate of misdiagnosis of the vegetative state. This should incite clinicians to use the most sensitive "coma scales" to detect signs of consciousness in these patients. The gold standard remains the Glasgow Coma Scale (GCS, Teasdale and Jennet, 1974), with the Glasgow Liege Scale (GLS, Born, 1988) adding standardized assessment of brainstem reflexes. New sensible behavioral assessment tools for use in the acute neurocritical care setting include the Full Outline of UnResponsiveness (FOUR, Wijdicks et al., 2005). The Coma Recovery Scale-Revised (CRS-R, Giacino and Kalmar, 2004) specifically tests the diagnostic criteria differentiating vegetative from minimally conscious patients. Detecting signs of consciousness also depends on the employed methodology. We showed that for the assesment of the presence of visual pursuit, using a moving mirror is better suited than using a moving object or person. The clinical diagnosis can be confirmed by cerebral positron emission tomography studies objectively quantifying residual metabolic activity in vegetative and minimally conscious patients. Ongoing studies evaluate the prognostic value of functional magnetic resonance imaging studies in these challenging patient populations. [less ▲]

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See detailTherapeutic use of high-frequency repetitive transcranial magnetic stimulation in stroke.
Hotermans, Christophe; Peigneux, Philippe ULg; Moonen, Gustave ULg et al

in Stroke (2007), 38(2), 253254

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See detailTherapeutic armamentarium in neurology: the birth of a new era
Belachew, Shibeshih ULg; Magis, Delphine ULg; Lievens, Isabelle ULg et al

in Revue Médicale de Liège (2007), 62(5-6), 432-448

The field of neurology was long infamous for a lack of therapeutic options. How many of you have once thought: "Neurologists don't cure the disease, they admire it". But those days have passed into ... [more ▼]

The field of neurology was long infamous for a lack of therapeutic options. How many of you have once thought: "Neurologists don't cure the disease, they admire it". But those days have passed into history, and the field is now vibrant with new treatments and hope even for patients with the worst neurodegenerative diseases. We summarized in the present review the latest major advances in therapeutic principles and practice for some of the most frequent chronic neurological disorders such as headaches, epilepsy, multiple sclerosis, dementias, Parkinson's disease, sleep/wake disturbances and peripheral neuropathies. We cannot cure or prevent, but we can now halt or control symptoms and disease progression to provide physical and psychological relief, and a better quality of life for patients who suffer from these otherwise devastating neurological conditions. [less ▲]

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See detailStudy of the interaction of antiplasmodial strychnine derivatives with the glycine receptor
Philippe, Geneviève ULg; Nguyen, Laurent ULg; Angenot, Luc ULg et al

in European Journal of Pharmacology (2006), 530(1-2), 15-22

Strychnos icaja Baill. (Loganiaccae) is a liana found in Central Africa known to be an arrow and ordeal poison but also used by traditional medicine to treat malaria. Recently, many dimeric or trimeric ... [more ▼]

Strychnos icaja Baill. (Loganiaccae) is a liana found in Central Africa known to be an arrow and ordeal poison but also used by traditional medicine to treat malaria. Recently, many dimeric or trimeric indolomonoterpenic alkaloids with antiplasmodial properties have been isolated from its rootbark. Since these alkaloids are derivatives of strychnine, it was important, in view of their potential use as antimalarial drugs, to assess their possible convulsant strychnine-like properties. In that regard, their interaction with the strychnine-sensitive glycine receptor was investigated by whole-cell patch-clamp recordings on glycine-gated currents in mouse spinal cord neurons in culture and by [H-3]strychnine competition assays on membranes from adult rat spinal cord. These experiments were carried out on sungucine (leading compound of the chemical class) and on the antiplasmodial strychnogucine B (dimeric) and strychnohexamine (trimeric). In comparison with strychnine, all compounds interact with a very poor efficacy and only at concentrations > I mu M with both [H-3]strychnine binding and glycine-gated currents. Furthermore, the effects of strychnine and protostrychnine, a monomeric alkaloid (without antiplasmodial activity) also isolated from S. icaja and differing from strychnine only by a cycle opening, were compared in the same way. The weak interaction of protostrychnine confirms the importance of the G cycle ring structure in strychnine for its binding to the glycine receptor and its antagonist properties. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailL'image du mois. Un cas de leucoencephalopathie rapidement progressive sur angiopathie amyloide
Wauters, Odile ULg; Scholtes, Félix ULg; Dive, Dominique ULg et al

in Revue Médicale de Liège (2006), 61(1), 3-4

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See detailRole of Sox 10 in the development of the inner ear
Bodson, M; Breuskin, I; Thelen, Nicolas ULg et al

Poster (2006)

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See detailEarly boost and slow consolidation in motor skill learning
Hotermans, C.; Peigneux, Philippe ULg; Maertens De Noordhout, Alain ULg et al

in Learning & Memory (Cold Spring Harbor, N.Y.) (2006), 13(5, Sep-Oct), 580-583

Motorskill learning is a dynamic process that continues covertly after training has ended and eventually leads to delayed increments in performance. Current theories Suggest that this off-line improvement ... [more ▼]

Motorskill learning is a dynamic process that continues covertly after training has ended and eventually leads to delayed increments in performance. Current theories Suggest that this off-line improvement takes time and appears only after several hours. Here we show an early transient and short-lived boost in performance, emerging as early as 5-30 min after training but no longer observed 4 h later. This early boost is predictive of the performance achieved 48 h later, Suggesting its functional relevance for memory processes. [less ▲]

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See detailBrain response to one's own name in vegetative state, minimally conscious state and locked-in syndrome
Perrin, F.; Schnakers, Caroline ULg; Schabus, M. et al

in Archives of Neurology (2006), 63

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See detailThe Yin and Yang of cell cycle progression and differentiation in the oligodendroglial lineage
Nguyen, Laurent ULg; Borgs, Laurence ULg; Vandenbosch, Renaud ULg et al

in Mental Retardation & Developmental Disabilities Research Reviews (2006), 12(2), 85-96

In white matter disorders such as leukodystrophies (LD), periventricular leucomalacia (PVL), or multiple sclerosis (MS), the hypomyelination or the remyelination failure by oligodendrocyte progenitor ... [more ▼]

In white matter disorders such as leukodystrophies (LD), periventricular leucomalacia (PVL), or multiple sclerosis (MS), the hypomyelination or the remyelination failure by oligodendrocyte progenitor cells involves errors in the sequence of events that normally occur during development when progenitors proliferate, migrate through the white matter, contact the axon, and differentiate into myelin-forming oligodendrocytes. Multiple mechanisms underlie the eventual progressive deterioration that typifies the natural history of developmental demyelination in LID and PVL and of adult-onset demyelination in MS. Over the past few years, pathophysiological studies have mostly focused on seeking abnormalities that impede oligodendroglial maturation at the level of migration, myelination, and survival. In contrast, there has been a strikingly lower interest for early proliferative and differentiation events that are likely to be equally critical for white matter development and myelin repair. This review highlights the Yin and Yang principles of interactions between intrinsic factors that coordinately regulate progenitor cell division and the onset of differentiation, i.e. the initial steps of oligodendrocyte lineage progression that are obviously crucial in health and diseases. (C) 2006 Wiley-Liss, Inc. [less ▲]

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See detailActivation of protein kinase CbetaI constitutes a new neurotrophic pathway for deafferented spiral ganglion neurons
Lallemend, François; Hadjab, Saida; Hans, Grégory ULg et al

in Journal of Cell Science (2005), 118(19), 4511-4525

In mammals, degeneration of peripheral auditory neurons constitutes one of the main causes of sensorineural hearing loss. Unfortunately, to date, pharmacological interventions aimed at counteracting this ... [more ▼]

In mammals, degeneration of peripheral auditory neurons constitutes one of the main causes of sensorineural hearing loss. Unfortunately, to date, pharmacological interventions aimed at counteracting this condition have not presented complete effectiveness in protecting the integrity of cochlear neural elements. In this context, the protein kinase C (PKC) family of enzymes are important signalling molecules that play a role in preventing neurodegeneration after nervous system injury. The present study demonstrates, for the first time, that the PKC signalling pathway is directly neurotrophic to axotomised spiral ganglion neurons (SGNs). We found that PKC beta I was strictly expressed by postnatal and adult SGNs both in situ and in vitro. In cultures of SGNs, we observed that activators of PKC, such as phorbol esters and bryostatin 1, induced neuronal survival and neurite regrowth in a manner dependent on the activation of PKC beta I. The neuroprotective effects of PKC activators were suppressed by pre-treatment with LY294002 (a PI3K inhibitor) and with U0126 (a MEK inhibitor), indicating that PKC activators promote the survival and neurite outgrowth of SGNs by both PI3K/Akt and MEK/ERK-dependent mechanisms. In addition, whereas combining the neurotrophins brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT3) was shown to provide only an additive effect on SGN survival, the interaction between PKC and neurotrophin signalling gave rise to a synergistic increase in SGN survival. Taken together, the data indicate that PKC beta I activation represents a key factor for the protection of the integrity of neural elements in the cochlea. [less ▲]

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See detailDevelopmental regulation of beta-carboline-induced inhibition of glycine-evoked responses depends on glycine receptor beta subunit expression
Mangin, Jean-Marie; Nguyen, Laurent ULg; Gougnard, Catherine et al

in Molecular Pharmacology (2005), 67(5), 1783-1796

In this work, we show that beta-carbolines, which are known negative allosteric modulators of GABA A receptors, inhibit glycine-induced currents of embryonic mouse spinal cord and hippocampal neurons. In ... [more ▼]

In this work, we show that beta-carbolines, which are known negative allosteric modulators of GABA A receptors, inhibit glycine-induced currents of embryonic mouse spinal cord and hippocampal neurons. In both cell types, beta-carboline-induced inhibition of glycine receptor (GlyR)-mediated responses decreases with time in culture. Single-channel recordings show that the major conductance levels of GlyR unitary currents shifts from high levels (>= 50 pS) in 2 to 3 days in vitro (DIV) neurons to low levels (< 50 pS) in 11 to 14 DIV neurons, assessing the replacement of functional homomeric GlyR by heteromeric GlyR. In cultured spinal cord neurons, the disappearance of beta-carboline inhibition of glycine responses and high conductance levels is almost complete in mature neurons, whereas a weaker decrease in beta-carboline-evoked glycine response inhibition and high conductance level proportion is observed in hippocampal neurons. To confirm the hypothesis that the decreased sensitivity of GlyR to beta-carbolines depends on beta subunit expression, Chinese hamster ovary cells were permanently transfected either with GlyR alpha 2 subunit alone or in combination with GlyR beta subunit. Single-channel recordings revealed that the major conductance levels shifted from high levels (>= 50 pS) in GlyR-alpha 2-transfected cells to low levels (< 50 pS) in GlyR-alpha 2-containing cells. Consistently, both picrotoxinand beta-carboline-induced inhibition of glycine-gated currents were significantly decreased in GlyR-alpha 2-transfected cells compared with GlyR-alpha 2-containing cells. In summary, we demonstrate that the incorporation of beta subunits in GlyRs confers resistance not only to picrotoxin but also to beta-carbolineinduced inhibition. Furthermore, we also provide evidence that hippocampal neurons undergo in vitro a partial maturation process of their GlyR-mediated responses. [less ▲]

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See detailPeripheral benzodiazepine receptor (PBR) ligand cytotoxicity unrelated to PBR expression
Hans, Grégory ULg; Wislet, Sabine ULg; Lallemend, François et al

in Biochemical Pharmacology (2005), 69(5), 819-830

Some synthetic ligands of the peripheral-type benzodiazepine receptor (PBR), an 18 kDa protein of the outer mitochondrial membrane, are cytotoxic for several tumor cell lines and arise as promising ... [more ▼]

Some synthetic ligands of the peripheral-type benzodiazepine receptor (PBR), an 18 kDa protein of the outer mitochondrial membrane, are cytotoxic for several tumor cell lines and arise as promising chemotherapeutic candidates. However, conflicting results were reported regarding the actual effect of these drugs on cellular survival ranging from protection to toxicity. Moreover, the concentrations needed to observe such a toxicity were usually high, far above the affinity range for their receptor, hence questioning its specificity. In the present study, we have shown that micromolar concentrations of FGIN-1-27 And Ro 5-4864, two chemically unrelated PBR ligands are toxic for both PBR-expressing SK-N-BE neuroblastoma cells and PBR-deficient Jurkat lymphoma cells. We have thereby demonstrated that the cytotoxicity of these drugs is unrelated to their PBR-binding activity. Moreover, Ro 54864-induced cell death differed strikingly between both cell types, being apoptotic in Jurkat cells while necrotic in SK-N-BE cells. Again, this did not seem to be related to PBR expression since Ro 5-4864-induced death of PBR-transfected Jurkat cells remained apoptotic. Taken together, our results show that PBR is unlikely to mediate all the effects of these PBR ligands. They however confirm that some of these ligands are very effective cytotoxic drugs towards various cancer cells, even for reputed chemoresistant tumors such as neuroblastoma, and, surprisingly, also for PBR-lacking tumor cells. (C) 2004 Elsevier Inc. All rights reserved. [less ▲]

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