Oclusión de la arteria de Percherón: Presentación atípica de Ictus isquémico / Percheron's artery oclussion: An atypical stroke syndrome

El tálamo posee una irrigación vascular compleja, llena de variantes anatómicas de relevancia para los estudiantes de la medicina. La presencia y el infarto producido por la oclusión de la arteria de Percherón es caracterizado por un cuadro clínico raro, poco conocido por los médicos del Servicio de Urgencias. Generalmente está asociado a la triada de alteración de la consciencia, parálisis de la mirada vertical y alteraciones de la memoria. Presentamos el caso de un varón de 54 años que se presenta con alteración del sensorio, somnolencia y alteraciones de la memoria, en el que no se pudo realizar terapia adecuada debido al desconocimiento de dicha entidad.

The thalamus has a complex vascular supply, full of anatomical variants of relevance to medical students. The presence of the Percheron artery is one of these anatomical variants, and the infarction produced by its occlusion is characterized by a rare clinical picture, little known by doctors in the Emergency Department. It is generally associated with the triad of impaired consciousness, vertical gaze palsy, and memory disturbance. We present the case of a 54-year-old man who presented with altered sensorium, drowsiness and memory alterations, in whom adequate therapy could not be carried out due to ignorance of this entity.

Evaluation of different methodologies for primary human dermal fibroblast spheroid formation: automation through 3D bioprinting technology.

Cell spheroids have recently emerged as an effective tool to recapitulate native microenvironments of living organisms in anin vitroscenario, increasing the reliability of the results obtained and broadening their applications in regenerative medicine, cancer research, disease modeling and drug screening. In this study the generation of spheroids containing primary human dermal fibroblasts was approached using the two-widely employed methods: hanging-drop and U-shape low adhesion plate (LA-plate). Moreover, extrusion-based three-dimensional (3D) bioprinting was introduced to achieve a standardized and scalable production of cell spheroids, decreasing considerably the possibilities of human error. This was ensured when U-shape LA-plates were used, showing an 85% formation efficiency, increasing up to a 98% when it was automatized using the 3D bioprinting technologies. However, sedimentation effect within the cartridge led to a reduction of 20% in size of the spheroid during the printing process. Hyaluronic acid (HA) was chosen as viscosity enhancer to supplement the bioink and overcome cell sedimentation within the cartridge due to the high viability values exhibited by the cells-around 80%-at the used conditions. Finally, (ANCOVA) of spheroid size over time for different printing conditions stand out HA 0.4% (w/v) 60 kDa as the viscosity-improved bioink that exhibit the highest cell viability and spheroid formation percentages. Besides, not only did it ensure cell spheroid homogeneity over time, reducing cell sedimentation effects, but also wider spheroid diameters over time with less variability, outperforming significantly manual loading.

Experiencia en la unidad de enfermedades desmielinizantes a 2 años / Experience in the demyelinating diseases unit after 2 years

La esclerosis múltiple es una enfermedad desmielinizante crónica que produce discapacidad progresiva, por lo que el tratamiento se centra en retrasar la progresión, prevenir recaídas y disminuir los síntomas de manera efectiva. Realizamos un estudio observacional, descriptivo, longitudinal, de un solo centro, con los pacientes admitidos en la unidad de enfermedades desmielinizantes, desde diciembre 2017 hasta febrero 2020. Del total de pacientes, 62.5% recibieron tratamiento con ocrelizumab y completaron seguimiento por 12 meses, sin progresión de la enfermedad. Con este estudio, resaltamos la importancia y la efectividad de los tratamientos modificadores de la enfermedad.

Multiple sclerosis is a chronic demyelinating disease that causes progressive disability, so treatment focuses on slowing progression, preventing relapses, and effectively reducing symptoms. We conducted an observational, descriptive, longitudinal, single-center study with patients admitted to the demyelinating diseases unit from December 2017 to February 2020. Of the total number of patients, 62.5% received treatment with ocrelizumab and completed 12-month follow-up, without disease progression. With this study, we highlight the importance and effectiveness of disease-modifying treatments

A truncated isoform of pyroglutamyl aminopeptidase II produced by exon extension has dominant-negative activity.

Thyrotropin-releasing hormone is inactivated in the extracellular space by a membrane-bound peptidase, pyroglutamyl aminopeptidase II (PPII), a member of the M1 family of zinc metallopeptidases. The functional significance of multiple PPII RNA species expression is unknown. We detected, in rat tissues, a RNA species derived from an alternative processing at the exon 14-intron 14 boundary. The alternatively processed RNA encoded a shorter version of PPII (PPII*), lacking part of the C-terminal domain. PPII* was expressed in COS-7 (or C6 glioma) cells but it did not exhibit any PPII activity. Co-transfection of PPII and increasing amounts of PPII* expression vectors resulted in a dose-dependent reduction in PPII activity and the formation of covalent PPII-PPII* heterodimers. PPII* is therefore a powerful dominant-negative isoform of PPII, and heterodimerization may be its mechanism of action. Natural expression of shortened versions of M1 aminopeptidases may constitute a new mode of regulation of their activity.

Visualization of translated tau protein in the axons of neuronal P19 cells and characterization of tau RNP granules.

Localization of tau mRNA to the axon requires the axonal localization cis signal (ALS), which is located within the 3' untranslated region, and trans-acting binding proteins, which are part of the observed granular structures in neuronal cells. In this study, using both biochemical and morphological methods, we show that the granules contain tau mRNA, HuD RNA-binding protein, which stabilizes mRNA, and KIF3A, a member of the kinesin microtubule-associated motor protein family involved in anterograde transport. The granules are detected along the axon and accumulate in the growth cone. Inhibition of KIF3A expression caused neurite retraction and inhibited tau mRNA axonal targeting. Taken together, these results suggest that HuD and KIF3A proteins are present in the tau mRNA axonal granules and suggest an additional function for the kinesin motor family in the microtubule-dependent translocation of RNA granules. Localized tau-GFP expression was blocked by a protein synthesis inhibitor, and upon release from inhibition, nascent tau-GFP 'hot spots' were directly observed in the axon and growth cones. These observations are consistent with local protein synthesis in the axon resulting from the transported tau mRNA.