Publications by authors named "Gallard J"

Introduction/aims: It is imperative to screen asymptomatic carriers of transthyretin (TTR) mutations to initiate treatment early. The protocol for repeated electrodiagnostic (EDX) assessments over time lacks standardization. Our aim was to report the electrophysiological evolution of a cohort of asymptomatic carriers and to determine which biomarkers were most sensitive to change.

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Introduction/aims: Cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS) is caused by RFC1 expansions. Sensory neuronopathy, polyneuropathy, and involvement of motor, autonomic, and cranial nerves have all been described with RFC1 expansions. We aimed to describe the electrodiagnostic features of patients with RFC1 expansions through multimodal electrophysiological investigations.

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Nanogels are aqueous dispersions of hydrogel particles formed by physically or chemically cross-linked polymer networks of nanoscale size. Herein, we devised a straightforward technique to fabricate a novel class of physically cross-linked nanogels via a self-assembly process in water involving α-cyclodextrin and a mannose molecule that was hydrophobically modified using an alkyl chain. The alkyl chain-modified mannose was synthesized in five steps, starting with D-mannose.

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Inspired by the multicomponent reaction-type scenario involving fatty dialdehydes, a nitrogen source, and acrolein, as a key C unit, put forward by Baldwin and Whitehead to explain the formation of manzamine-type alkaloids, 96 multicomponent reactions were designed, and their analytical readouts were deconvoluted using a herein-provided chemoinformatic workflow. This strategy pinpointed relevant conditions tuning the reactivity of acrolein to fulfill Baldwin and Whitehead's manzamine alkaloids biosynthetic hypothesis. This strategy can become part of a general method for the high-content analysis of multicomponent reactions applied to a natural product biosynthetic scenario.

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Applying a single molecular probe to monitor enzymatic activities in multiple, complementary imaging modalities is highly desirable to ascertain detection and to avoid the complexity associated with the use of agents of different chemical entities. We demonstrate here the versatility of lanthanide (Ln) complexes with respect to their optical and magnetic properties and their potential for enzymatic detection in NIR luminescence, CEST and T1 MR imaging, controlled by the nature of the Ln ion, while using a unique chelator. Based on X-ray structural, photophysical, and solution NMR investigations of a family of Ln DO3A-pyridine model complexes, we could rationalize the luminescence (Eu, Yb), CEST (Yb) and relaxation (Gd) properties and their variations between carbamate and amine derivatives.

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Chemical investigation of the emblematic led to the discovery of trirosaline (), the first example of a tris-ajmalicine-type monoterpene indole alkaloid and the first natural trimeric MIA ever reported from this deeply dug plant species. Its structure was primarily elucidated based on NMR and HRESIMS analyses, and the nature of its unique intermonomeric linkages was firmly confirmed based on a combination of empirical computation and ML--DP4 study. Its absolute configuration was mitigated by comparison of experimental and TDDFT-simulated electronic circular dichroism (ECD) spectra.

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A novel class of peptidomimetic foldamers based on diaza-peptide units are reported. Circular dichroism, attenuated total reflection -Fourier transform infrared, NMR, and molecular dynamics studies demonstrate that unlike the natural parent nonapeptide, the specific incorporation of one diaza-peptide unit at the N-terminus allows helical folding in water, which is further reinforced by the introduction of a second unit at the C-terminus. The ability of these foldamers to resist proteolysis, to mimic the small helical hot spot of transthyretin-amyloid β (Aβ) cross-interaction, and to decrease pathological Aβ aggregation demonstrates that the introduction of diaza-peptide units is a valid approach for designing mimics or inhibitors of protein-protein interaction and other therapeutic peptidomimetics.

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Article Synopsis
  • Research involved a detailed analysis of borrecapine and borreline using advanced spectroscopy techniques to assess their structures.
  • Findings revealed that the previously believed relative configuration for borrecapine was inaccurate.
  • It was also determined that the absolute configuration of borreline needs to be changed to its enantiomer instead of the previously claimed one.
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The molecular network-guided exploration of the alkaloid extract of stems revealed a cluster attributed tentatively to dimeric monoterpene indole alkaloids of the rare criophylline subtype, initiating the dual study reported herein. A patrimonial-themed portion of this work was aimed at performing a spectroscopic reassessment of criophylline (), a monoterpene bisindole alkaloid for which the nature of the inter-monomeric connectivity and configurational assignments have remained dubious. A targeted isolation of the entity annotated as criophylline () was undertaken to strengthen the available analytical evidence.

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Since its partial configurational assignment in 1964, pandamine has not been isolated or obtained by total synthesis. For decades, different works representing the structure of pandamine for illustrative purposes have lent different configurations to this molecule, causing tenacious confusion about the structure of this ansapeptide. A comprehensive spectroscopic analysis of the authentic pandamine sample led to the complete and unambiguous assignment of its configuration, 59 years after its isolation.

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The UHPLC-HRMS analysis of basidiomata extract revealed that this mushroom accumulated elevated yields of an unreported specialized metabolite. The molecular formula of this unknown compound, CHO, indicated that a challenging structure elucidation lay ahead, owing to its critically low H/C atom ratio. The structure of this new isolate, namely ominoxanthone (), could not be solved from the interpretation of the usual set of 1D/2D NMR data that conveyed too limited information to afford a single, unambiguous structure.

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The structure and complete NMR assignments of aspidoreticulofractine, an aspidofractinine -oxide, are reported. Its structure was elucidated based on a combination of spectroscopic techniques including 1D and 2D NMR, high-resolution mass spectrometry, and electronic circular dichroism.

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Improved methodological tools to hasten antimalarial drug discovery remain of interest, especially when considering natural products as a source of drug candidates. We propose a biodereplication method combining the classical dereplication approach with the early detection of potential antiplasmodial compounds in crude extracts. Heme binding is used as a surrogate of the antiplasmodial activity and is monitored by mass spectrometry in a biomimetic assay.

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Background: Adults with Down syndrome (DS) are at increased risk of developing Alzheimer's disease (AD) due to genetic predisposition. Identification of patients with AD is difficult since intellectual disabilities (ID) may confound diagnosis. The objective of this study was to evaluate the ability of the French version of the modified cued recall test (mCRT) to distinguish between subjects with and without AD in the adult DS population.

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The structure elucidation of theionbrunonine C, a thioether-bridged dimeric monoterpene indole alkaloid (MIA), and more generally, one of the very few sulfur-containing MIA, is reported after its isolation from Mostuea brunonis (Gelsemiaceae). This unstable structure had already been targeted for isolation in our former, molecular network-guided, investigation of this plant, but this compound had degraded before sufficient spectroscopic data could have been acquired for a complete structure assignment. With this constraint in mind, the rapid acquisition of nuclear magnetic resonance (NMR) data enabled retrieving sufficient spectroscopic information for full structure elucidation, although from a partial set of spectroscopic information ( H and C NMR; COSY, HSQC, and HMBC).

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Children with Down syndrome (DS) show delayed acquisition of cognitive and functional skills compared to typically developing children. The objective of this study was to accurately describe early development of infants and young children (children hereafter) with DS based on a large recent sample. We carried out repeated measure analysis of the global development quotient (GDQ) and developmental age using data from the Assessment of Systematic Treatment with Folinic Acid and Thyroid Hormone on Psychomotor Development of Down Syndrome Young Children (ACTHYF) study (NCT01576705).

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A new vobasine-tryptamine-based monoterpene indole alkaloid pseudodimer was isolated from the stem bark of . As a minor constituent occurring in a thoroughly investigated plant, this molecule was targeted based on a molecular networking strategy and a rational MS-guided phytochemical investigation led to its isolation. Its structure was formally established based on HRMS, 1D/2D NMR data, and the application of the tool Small Molecule Accurate Recognition Technology (SMART 2.

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Voatriafricanines A and B ( and ), the first examples of vobasine-aspidosperma-aspidosperma monoterpene trisindole alkaloids, were isolated from the stem barks of , guided by a molecular networking strategy. Their structures, including absolute configurations, were elucidated by spectroscopic methods and ECD calculations. Compounds and possess intramolecular hydrogen bonding, sufficiently robust to transfer homonuclear and heteronuclear magnetizations.

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Lyaline () is a monoterpene indole alkaloid that was isolated in 1974 from (Rubiaceae) in our laboratory and has not been reported elsewhere since then. Its structure was proposed on the basis of a very limited set of spectroscopic data (viz., H NMR and EIMS) as a structurally bizarre harman-1,4-dihydropyridine derivative.

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The structure and complete nuclear magnetic resonance (NMR) assignments of orbifomitellic acid, a novel lanostane triterpene isolated from the fruiting bodies of a Gabonese Ganoderma orbiforme (Polyporaceae), are reported. Within the vast catalogue of lanostanes documented from Ganoderma spp., orbifomitellic acid is the first disclosing a -COOH group at C-4.

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Down syndrome (DS) is a genetic neurodevelopmental disorder. In individuals with DS, a multidisciplinary approach to care is required to prevent multiple medical complications. The aim of this study was to describe the rehabilitation, medical care, and educational and social support provided to school-aged French DS patients with varying neuropsychological profiles.

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Melonine is a basic monoterpene indole alkaloid (MIA) skeleton from that was reported in 1983. The scarcity of its spectroscopic data questioned the validity of its structure. This prompted us to reisolate this molecule and to revise its structure into an unprecedented MIA scaffold.

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Article Synopsis
  • Smith-Magenis syndrome (SMS) is primarily caused by a deletion on chromosome 17p11.2 or mutations in the RAI1 gene, affecting patients with characteristic features such as neurodevelopmental disorders and sleep issues.
  • In a study of 47 European patients, it was found that while most had normal growth, a significant number experienced obesity, heart defects, and common vision and hearing problems, with obesity being reported in 60% of those over 10 years.
  • All patients had learning difficulties, with a wide range of intellectual disabilities and challenging behaviors like tantrums and sleep disturbances, highlighting the need for comprehensive care and parental adjustments to support their educational needs.
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Prader-Willi syndrome (PWS) is a rare genetic neurodevelopmental disorder with a characteristic behavioural phenotype. A multidisciplinary approach to care is required to prevent multiple medical complications in individuals affected by PWS. The aim of this study was to describe the rehabilitation, medical care, educational and social support provided to school-aged French PWS patients with varying neuropsychological profiles.

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