Imaging crossing fibers in mouse, pig, monkey, and human brain using small-angle X-ray scattering.

Myelinated axons (nerve fibers) efficiently transmit signals throughout the brain via action potentials. Multiple methods that are sensitive to axon orientations, from microscopy to magnetic resonance imaging, aim to reconstruct the brain's structural connectome. As billions of nerve fibers traverse the brain with various possible geometries at each point, resolving fiber crossings is necessary to generate accurate structural connectivity maps. However, doing so with specificity is a challenging task because signals originating from oriented fibers can be influenced by brain (micro)structures unrelated to myelinated axons. X-ray scattering can specifically probe myelinated axons due to the periodicity of the myelin sheath, which yields distinct peaks in the scattering pattern. Here, we show that small-angle X-ray scattering (SAXS) can be used to detect myelinated, axon-specific fiber crossings. We first demonstrate the capability using strips of human corpus callosum to create artificial double- and triple-crossing fiber geometries, and we then apply the method in mouse, pig, vervet monkey, and human brains. We compare results to polarized light imaging (3D-PLI), tracer experiments, and to outputs from diffusion MRI that sometimes fails to detect crossings. Given its specificity, capability of 3-dimensional sampling and high resolution, SAXS could serve as a ground truth for validating fiber orientations derived using diffusion MRI as well as microscopy-based methods. STATEMENT OF SIGNIFICANCE: To study how the nerve fibers in our brain are interconnected, scientists need to visualize their trajectories, which often cross one another. Here, we show the unique capacity of small-angle X-ray scattering (SAXS) to study these fiber crossings without use of labeling, taking advantage of SAXS's specificity to myelin - the insulating sheath that is wrapped around nerve fibers. We use SAXS to detect double and triple crossing fibers and unveil intricate crossings in mouse, pig, vervet monkey, and human brains. This non-destructive method can uncover complex fiber trajectories and validate other less specific imaging methods (e.g., MRI or microscopy), towards accurate mapping of neuronal connectivity in the animal and human brain.

Seguridad del paciente, su percepción por el personal de enfermería en un hospital materno-infantil / Patient safety: Nursing staff´s perception in a mother and child hospital / Segurança do paciente, sua percepção pela equipe de enfermagem em um hospital materno-infantil

RESUMEN Introducción: La seguridad del paciente constituye un desafío para el personal de enfermería, por lo que se hace necesario el desarrollo, seguimiento y evaluación de indicadores de calidad y seguridad medibles, objetivos, relevantes y basados en la evidencia. Objetivo: Describir las percepciones sobre la cultura de seguridad del paciente en el personal de enfermería del servicio de cuidados críticos en un hospital materno-infantil de la Ciudad Autónoma de Buenos Aires. Método: Se realizó un estudio observacional, descriptivo, de corte transversal entre los meses de agosto y octubre de 2021. La población accesible estuvo constituida por 57 profesionales de enfermería. Se utilizó como instrumento el Hospital Survey on Patient Safety Culture. Resultados: Luego del análisis de las percepciones según dimensiones se encontró que la dimensión con valores más altos fue de 7 sobre la retroalimentación y comunicación sobre errores. El resto de las dimensiones obtuvieron puntuaciones en el rango de lo neutral, con valores menores o iguales a 4 puntos. Se aplicó la prueba de Kruskal-Wallis, y no se hallaron diferencias estadísticamente significativas entre los grupos en ninguna de las cuatro variables analizadas. Conclusiones: El análisis de la cultura de seguridad del paciente encontró percepciones no negativas donde la retroalimentación y comunicación sobre errores fue la única dimensión con puntuación positiva entre los enfermeros encuestados. Por último, destaca el hecho que no se pude establecer que la cultura organizacional de seguridad del paciente estuviera condicionada por indicadores sociodemográficos o de formación.

ABSTRACT Introduction: Patient safety is a challenge for nurses, so it is necessary to develop, monitor and evaluate quality and safety indicators that are measurable, objective, relevant and based in real evidence. Objective: To describe the perceptions concerning the patient safety culture among the nursing staff of the Critical care service in a mother and child hospital in the Ciudad Autónoma de Buenos Aires. Method: An observational, descriptive, cross-sectional, descriptive study was conducted between August and October 2021. The accessible population consisted of 57 nursing professionals. The Hospital Survey on Patient Safety Culture was used as an instrument. Results: After analyzing the perceptions according to dimensions, it was found that the dimension with the highest values was 7 at feedback and communication about errors. The rest of the dimensions obtained scores in neutral range, with values less than or equal to 4 points. The Kruskal-Wallis test was applied, and no statistically significant differences were found between the groups in any of the four variables analyzed. Conclusions: In the analysis concerning patient safety culture found non-negative perceptions where feedback and communication about errors was the only dimension with a positive score among the nurses surveyed. Finally, it should be noted that it was not possible to establish that the organizational culture of patient safety was conditioned by sociodemographic or training indicators.

RESUMO Introdução: A segurança do paciente é um desafio para a equipe de enfermagem, por isso é necessário o desenvolvimento, monitoramento e avaliação de indicadores de qualidade e segurança mensuráveis, objetivos, relevantes e baseados em evidências. Objetivo: Descrever as percepções sobre a cultura de segurança do paciente na equipe de enfermagem do serviço de cuidados intensivos em um hospital materno-infantil da Ciudad Autónoma de Buenos Aires. Método: Estudo observacional, descritivo, transversal, realizado entre os meses de agosto e outubro de 2021. A população acessível foi composta por 57 profissionais de enfermagem. O Hospital Survey on Patient Safety Culture foi utilizado como instrumento. Resultados: Após analisar as percepções de acordo com as dimensões, verificou-se que a dimensão com maiores valores foi 7 no feedback e comunicação sobre erros. As demais dimensões obtiveram pontuações na faixa neutra, com valores menores ou iguais a 4 pontos. Aplicou-se o teste de Kruskal-Wallis e não foram encontradas diferenças estatisticamente significativas entre os grupos em nenhuma das quatro variáveis analisadas. Conclusões: A análise da cultura de segurança do paciente encontrou percepções não negativas onde o feedback e a comunicação sobre os erros foi a única dimensão com pontuação positiva entre os enfermeiros pesquisados. Por fim, destaca o fato de que não foi possível estabelecer que a cultura organizacional de segurança do paciente fosse condicionada por indicadores sociodemográficos ou de treinamento.

Early High-Titer Plasma Therapy to Prevent Severe Covid-19 in Older Adults.

BACKGROUND: Therapies to interrupt the progression of early coronavirus disease 2019 (Covid-19) remain elusive. Among them, convalescent plasma administered to hospitalized patients has been unsuccessful, perhaps because antibodies should be administered earlier in the course of illness. METHODS: We conducted a randomized, double-blind, placebo-controlled trial of convalescent plasma with high IgG titers against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in older adult patients within 72 hours after the onset of mild Covid-19 symptoms. The primary end point was severe respiratory disease, defined as a respiratory rate of 30 breaths per minute or more, an oxygen saturation of less than 93% while the patient was breathing ambient air, or both. The trial was stopped early at 76% of its projected sample size because cases of Covid-19 in the trial region decreased considerably and steady enrollment of trial patients became virtually impossible. RESULTS: A total of 160 patients underwent randomization. In the intention-to-treat population, severe respiratory disease developed in 13 of 80 patients (16%) who received convalescent plasma and 25 of 80 patients (31%) who received placebo (relative risk, 0.52; 95% confidence interval [CI], 0.29 to 0.94; P = 0.03), with a relative risk reduction of 48%. A modified intention-to-treat analysis that excluded 6 patients who had a primary end-point event before infusion of convalescent plasma or placebo showed a larger effect size (relative risk, 0.40; 95% CI, 0.20 to 0.81). No solicited adverse events were observed. CONCLUSIONS: Early administration of high-titer convalescent plasma against SARS-CoV-2 to mildly ill infected older adults reduced the progression of Covid-19. (Funded by the Bill and Melinda Gates Foundation and the Fundación INFANT Pandemic Fund; Dirección de Sangre y Medicina Transfusional del Ministerio de Salud number, PAEPCC19, Plataforma de Registro Informatizado de Investigaciones en Salud number, 1421, and ClinicalTrials.gov number, NCT04479163.).