Publications by authors named "Dubreuil D"

Article Synopsis
  • Scientists studied how mobile phone signals affect rats' brains and thinking.
  • They found that exposure to certain levels of signals changed brain activity, especially in areas that help with memory and thinking.
  • Even though there were changes in brain patterns, the rats still performed normally in memory tests, showing no big problems with their thinking skills.
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Magnetic resonance imaging (MRI) is a non-invasive technique that requires the participant to be completely motionless. To date, MRI in awake and unrestrained animals has only been achieved with humans and dogs. For other species, alternative techniques such as anesthesia, restraint and/or sedation have been necessary.

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Itch is an unpleasant sensation that evokes a desire to scratch. The skin barrier is constantly exposed to microbes and their products. However, the role of microbes in itch generation is unknown.

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Cortical neural dynamics mediate information processing for the cerebral cortex, which is implicated in fundamental biological processes such as vision and olfaction, in addition to neurological and psychiatric diseases. Spontaneous pain is a key feature of human neuropathic pain. Whether spontaneous pain pushes the cortical network into an aberrant state and, if so, whether it can be brought back to a "normal" operating range to ameliorate pain are unknown.

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Sensory neuron hyperexcitability is a critical driver of pathological pain and can result from axon damage, inflammation, or neuronal stress. G-protein coupled receptor signaling can induce pain amplification by modulating the activation of Trp-family ionotropic receptors and voltage-gated ion channels. Here, we sought to use calcium imaging to identify novel inhibitors of the intracellular pathways that mediate sensory neuron sensitization and lead to hyperexcitability.

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Since the decline of the use of bisphenol A, the chemistry of the varnishes and coatings which are applied to the inner surfaces of metallic food contact materials is poorly documented. We hypothesised that can coatings are now diverse and bring forth various non-intentionally added substances (NIAS) to be described. Investigating complex components such as NIAS requires demanding non-targeted approaches.

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Human induced pluripotent stem cells (iPSC) hold promise for modeling diseases in individual human genetic backgrounds and thus for developing precision medicine. Here, we generate sensorimotor organoids containing physiologically functional neuromuscular junctions (NMJs) and apply the model to different subgroups of amyotrophic lateral sclerosis (ALS). Using a range of molecular, genomic, and physiological techniques, we identify and characterize motor neurons and skeletal muscle, along with sensory neurons, astrocytes, microglia, and vasculature.

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High-throughput physiological assays lose single-cell resolution, precluding subtype-specific analyses of activation mechanism and drug effects. We demonstrate APPOINT (automated physiological phenotyping of individual neuronal types), a physiological assay platform combining calcium imaging, robotic liquid handling, and automated analysis to generate physiological activation profiles of single neurons at large scale. Using unbiased techniques, we quantify responses to sequential stimuli, enabling subgroup identification by physiology and probing of distinct mechanisms of neuronal activation within subgroups.

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Schwannomas are benign neoplasms that can cause gain- and loss-of-function neurological phenotypes, including severe, intractable pain. To investigate the molecular mechanisms underlying schwannoma-associated pain we compared the RNA sequencing profile of painful and non-painful schwannomas from NF2 patients. Distinct segregation of painful and non-painful tumors by gene expression patterns was observed.

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Interleukin (IL)-15 is a pleiotropic cytokine structurally close to IL-2 and sharing with the IL-2Rβ and γc receptor (R) subunits. IL-15 plays important roles in innate and adaptative immunity, supporting the activation and proliferation of NK, NK-T, and CD8 T cells. Over-expression of IL-15 has been shown to participate to the development of inflammatory and autoimmune diseases and diverse T cell malignancies.

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A direct and efficient regioselective C7-bromination of 4-substituted 1-indazole has been achieved. Subsequently, a successful palladium-mediated Suzuki-Miyaura reaction of C7-bromo-4-substituted-1-indazoles with boronic acids has been performed under optimized reaction conditions. A series of new C7 arylated 4-substituted 1-indazoles was obtained in moderate to good yields.

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A new Ru complex containing the deprotonated 2,2':6',2''-terpyridine-6,6''-diphosphonic acid (HtPa) and pyridine (py) of general formula [Ru(HtPa-κ-NO)(py)], , has been prepared and thoroughly characterized by means of spectroscopic and electrochemical techniques, X-ray diffraction analysis, and density functional theory (DFT) calculations. Complex presents a dynamic behavior in the solution that involves the synchronous coordination and the decoordination of the dangling phosphonic groups of the tPa ligand. However, at oxidation state IV, complex becomes seven coordinated with the two phosphonic groups now bonded to the metal center.

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Small Conductance Calcium (Ca)-activated potassium (K) channels (SKCa) are now proved to be involved in many cancer cell behaviors such as proliferation or migration. The SK3 channel isoform was particularly described in breast cancer where it can be associated with the Orai1 Ca channel to form a complex that regulates the Ca homeostasis during tumor development and acts as a potent mediator of bone metastases development in vivo. Until now, very few specific blockers of Orai1 and/or SK3 have been developed as potential anti-metastatic compounds.

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Directed differentiation of human pluripotent stem cells (hPSCs) has enabled the generation of specific neuronal subtypes that approximate the intended primary mammalian cells on both the RNA and protein levels. These cells offer unique opportunities, including insights into mechanistic understanding of the early driving events in neurodegenerative disease, replacement of degenerating cell populations, and compound identification and evaluation in the context of precision medicine. However, whether the derived neurons indeed recapitulate the physiological features of the desired bona fide neuronal subgroups remains an unanswered question and one important for validating stem cell models as accurate functional representations of the primary cell types.

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iNKT cells recognize CD1d/α-galactosylceramide (α-GalCer) complexes via their invariant TCR receptor and stimulate the immune response. Many α-GalCer analogues have been investigated to interrogate this interaction. Following our previous work related to the modification of the hydrogen bond network between α-GalCer and CD1d, we have now focused our attention on the synthesis of 3-deoxy-3,3-difluoro- and 3,4-dideoxy-3,3,4,4-tetrafluoro-α-GalCer analogues, and studied their ability to stimulate human iNKT cells.

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Various 3-amino-, 3-aryloxy- and alkoxy-6-arylpyridazines have been synthesized by an electrochemical reductive cross-coupling between 3-amino-, 3-aryloxy- or 3-alkoxy-6-chloropyridazines and aryl or heteroaryl halides. In vitro antiproliferative activity of these products was evaluated against a representative panel of cancer cell lines (HuH7, CaCo-2, MDA-MB-231, HCT116, PC3, NCI-H727, HaCaT) and oncogenicity prevention of the more efficient derivatives was highlighted on human breast cancer cell line MDA-MB 468-Luc prior establishing their interaction with p44/42 and Akt-dependent signaling pathways.

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Interleukin (IL)-15 is a pleiotropic cytokine, which is structurally close to IL-2 and shares with it the IL-2 β and γ receptor (R) subunits. By promoting the activation and proliferation of NK, NK-T, and CD8+ T cells, IL-15 plays important roles in innate and adaptative immunity. Moreover, the association of high levels of IL-15 expression with inflammatory and autoimmune diseases has led to the development of various antagonistic approaches targeting IL-15.

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Article Synopsis
  • Development of foldamer-based receptors involves designing specific monomers, such as a new pyridazine-pyridine-pyridazine diacid monomer.
  • This new monomer allows for a wide helix diameter in helical aromatic oligoamide foldamers, enabling them to sequester metal ions inside the cavity.
  • The interaction of metal ions promotes guest binding within the foldamer, while in their absence, the monomer leads to aggregation and the formation of intertwined structures.
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An original and efficient stereocontrolled synthesis of ribonucleosidic homo- and heterodimers has been achieved from inexpensive d-xylose. This successful strategy involved the sequential introduction of nucleobases, using two stereocontrolled N-glycosidation reactions, from a common two-furanoside amide-linked scaffold offering the possibility of obtaining any given base sequence. The pertinence of this approach is illustrated through the preparation of the homodimers UU-34 and TT-35 in 18 steps with an excellent overall yield of more than 10% from d-xylose, while the heterodimer route led to UT-39 in 19 steps with around 10% overall yield.

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A new strategy for the synthesis of acyl β-C-glycosides is described. The reactivity of glyconitriles toward organometallic reagents such as organomagnesium or organolithium derivatives was studied, affording acyl β-C-glycosides in moderate to good yields. In this study, glycal formation was efficiently prevented by deprotonating the hydroxyl group in position 2 of the glyconitriles during the process.

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The ab initio design of synthetic molecular receptors for a specific biomolecular guest remains an elusive objective, particularly for targets such as monosaccharides, which have very close structural analogues. Here we report a powerful approach to produce receptors with very high selectivity for specific monosaccharides and, as a demonstration, we develop a foldamer that selectively encapsulates fructose. The approach uses an iterative design process that exploits the modular structure of folded synthetic oligomer sequences in conjunction with molecular modelling and structural characterization to inform subsequent refinements.

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Synthesis of the originally proposed 8-oxo-8H-acenaphtho[1,2-b]pyrrol-9-carbonitrile led to a structural revision, and the product has now been identified as unknown compound 1-oxo-1H-phenalene-2,3-dicarbonitrile. The structural assignment was corroborated by detailed NMR studies and unambiguously confirmed by X-ray diffraction. A mechanism is proposed to explain the formation of this original heterocyclic scaffold.

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The synthesis and evaluation of new extractants for spent nuclear fuel reprocessing are described. New bitopic ligands constituted of phenanthroline and 1,3,5-triazine cores functionalized by picolinamide groups were designed. Synthetic routes were investigated and optimized to obtain twelve new polyaza-heterocyclic ligands.

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