BASHY Dye Platform Enables the Fluorescence Bioimaging of Myelin Debris Phagocytosis by Microglia during Demyelination.

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system that is characterized by the presence of demyelinated regions with accumulated myelin lipid debris. Importantly, to allow effective remyelination, such debris must be cleared by microglia. Therefore, the study of microglial activity with sensitive tools is of great interest to better monitor the MS clinical course. Using a boronic acid-based (BASHY) fluorophore, specific for nonpolar lipid aggregates, we aimed to address BASHY's ability to label nonpolar myelin debris and image myelin clearance in the context of demyelination. Demyelinated ex vivo organotypic cultures (OCSCs) and primary microglia cells were immunostained to evaluate BASHY's co-localization with myelin debris and also to evaluate BASHY's specificity for phagocytosing cells. Additionally, mice induced with experimental autoimmune encephalomyelitis (EAE) were injected with BASHY and posteriorly analyzed to evaluate BASHY+ microglia within demyelinated lesions. Indeed, in our in vitro and ex vivo studies, we showed a significant increase in BASHY labeling in demyelinated OCSCs, mostly co-localized with Iba1-expressing amoeboid/phagocytic microglia. Most importantly, BASHY's presence was also found within demyelinated areas of EAE mice, essentially co-localizing with lesion-associated Iba1+ cells, evidencing BASHY's potential for the in vivo bioimaging of myelin clearance and myelin-carrying microglia in regions of active demyelination.

Efficient Amino-Sulfhydryl Stapling on Peptides and Proteins Using Bifunctional NHS-Activated Acrylamides.

Widely used reagents in the peptide functionalization toolbox, Michael acceptors and N-hydroxysuccinimide (NHS) activated esters, are combined in NHS-activated acrylamides for efficient chemoselective amino-sulfhydryl stapling on native peptides and proteins. NHS-activated acrylamides allow for a fast functionalization of N-terminal cysteines (k2 =1.54±0.18×103  M-1 s-1 ) under dilute aqueous conditions, enabling selectivity over other nucleophilic amino acids. Additionally, the versatility of these new bioconjugation handles was demonstrated in the cross-linking of in-chain or C-terminal cysteines with nearby lysine residues. NHS-activated acrylamides are compatible with the use of other cysteine selective reagents, allowing for orthogonal dual-modifications. This strategy was successfully applied to the late-stage functionalization of peptides and proteins with a PEG unit, fluorescent probe, and cytotoxic agent. The level of molecular control offered by NHS-activated acrylamides is expected to promote amino-sulfhydryl stapling technology as a powerful strategy to design functional bioconjugates.

Evaluación del desempeño clínico del radiólogo en el diagnóstico de la displasia fibrosa ósea: estudio de concordacia / Diagnostic concordance among radiologist in fibrous dysplasia cases

Introducción: la displasia fibrosa ósea es una entidad benigna que se caracteriza por la incapacidad para producir hueso lamelar maduro. Dependiendo de la proporción que exista entre hueso y tejido fibroso la apariencia radiológica es variable. Objetivo: establecer el grado, de acuerdo entre el consenso de dos radiólogos, y el diagnóstico definitivo, emitido por un grupo de expertos. Adicionalmente, describir los hallazgos radiológicos donde el diagnóstico fue acertado. Tipo de estudio: estudio de concordancia. Lugar del estudio: Instituto Nacional de Cancerología (Bogotá). Pacientes y métodos: 45 pacientes con sospecha por imágenes de displasia fibrosa ósea y diagnóstico definitivo por correlación clínica, radiológica e histológica, se realizaron pruebas de concordancia para evaluar el desempeño clínico de los radiólogos y la frecuencia de los hallazgos en los casos acertados. Resultados: los diagnósticos diferenciales fueron osteomielitis, encondroma solitario, encondromatosis múltiple, osteoblastoma, quiste óseo solitario y fibroma no osificante. La coincidencia entre el diagnóstico radiológico y el diagnóstico definitivo fue considerada sustancial o muy buena (kappa 0,6353). Las cinco patologías donde no hubo acuerdo diagnóstico fueron: la mastocitosis ósea poliostótica, el granuloma reparativo de células gigantes, el fibroma cemento-osificante, el fibroma no osificante y la osteomielitis crónica. La presentación radiológica del granuloma reparativo de células gigantes y el fibroma cemento-osificante son indistinguibles de la displasia fibrosa ósea, por lo tanto, se hace necesaria la confirmación histológica