ABSTRACT
Annual fish have become attractive study models for a wide range of disciplines, including neurobiology. These fish have developed different survival strategies. As a result, their nervous system is under considerable selective pressure when facing extreme environmental situations. Fish from the Austrolebias group exhibit rapid neurogenesis in different brain regions, possibly as a result of the demanding conditions of a changing habitat. Knowledge of cerebral histology is essential for detecting ontogenic, anatomical, or cytoarchitectonic changes in the brain during the short lifespan of these fish, such as those reflecting functional adaptive plasticity in different systems, including sensory structures. The generation of an atlas of Garcialebias charrua (previously known as Austrolebias charrua) establishes its anatomical basis as a representative of a large group of fish that share similarities in their way of life. In this work, we present a detailed study of both gross anatomy and microscopic anatomy obtained through serial sections stained with the Nissl technique in three orientations: transverse, horizontal, and parasagittal planes. This atlas includes accurate drawings of the entire adult brain of the male fish Garcialebias charrua, showing dorsal, ventral, and lateral views, including where emergence and origin of cranial nerves. This brain atlas allows us to understand histoarchitecture as well as the location of neural structures that change during adult neurogenesis, enabling comparisons within the genus. Simultaneously, this atlas constitutes a valuable tool for comparing the brains of other fish species with different behaviors and neuroecologies.
ABSTRACT
El presente trabajo muestra los resultados de un estudio de carácter diagnóstico sobre el efecto de la aplicación de una metodología de enseñanza totalmente virtual para el curso ESFUNO de Facultad de Enfermería en el marco de la pandemia por Covid-19. Se realizó un estudio observacional descriptivo y analítico comparando el desempeño académico entre las generaciones del año 2019 y 2020 mediante contraste de proporciones. Se sistematizaron los datos de desempeño estudiantil para la exoneración del curso ESFUNO y los dos primeros períodos de exámenes a partir de la finalización del curso desarrollados desde la implementación del Plan 2016. A partir de los datos obtenidos se pudo observar que predominó la exoneración del curso con un porcentaje para el año 2019 de 56 % y para el año 2020 de 79 % siendo este un aumento significativo (p<0.05). Se observó un aumento significativo de la desvinculación en el año 2020 con respecto al año 2019 (27 % y 19 % respectivamente) (p<0.05). La proporción de estudiantes que salvaron el examen de ESFUNO aumento significativamente en el segundo periodo para el año 2019 (p<0.05) pero no así para el año 2020 (p>0.05). Al comparar la proporción de aprobación del primer periodo entre la generación que cursó en 2019y la generación que cursó en 2020 se observó un aumento significativo para el año 2020 (p<0.05). Finalmente se observó que en el año 2020 hubo una asociación positiva entre aquellos alumnos que sin exonerar tuvieron una nota media (5) y un mayor porcentaje de aprobación del examen. Se concluye que la utilización de la total virtualidad aplicada en el año 2020 en el curso ESFUNO no tuvo un impacto negativo sobre los niveles de aprobación del mismo ya sea a nivel de exoneración como a nivel de aprobación en el primer y segundo periodo de examen.
This work shows the results of a diagnostic study on the effect of the application of a totally virtual teaching methodology for the ESFUNO course of the School of Nursing, in the frame work of the Covid-19 pandemic. A descriptive and analytical observational study was carried out to compare academic performances between the 2019 and 2020 class by comparing proportions. Student performance data were systematized for the ESFUNO exam exemption and the first two exam periods immediately after the end of the course, for all the years since the implementation of the 2016 Plan. From the data obtained, it was observed that the exam exemption prevailed with a 56 % for the 2019 class and for a 79 % for the2020 class, this being a significant increase (p<0.05). A significant increase in disengagement was observed in 2020compared to 2019 (27 % and 19 % respectively) (p<0.05). The proportion of students who saved the ESFUNO exam in the second period, increased significantly for 2019 (p<0.05) but not for 2020 class (p>0.05). When comparing the passing rate during the first period between the 2019 and 2020 classes, a significant increase was observed for 2020 (p<0.05). Finally, it was observed that in 2020 there was a positive association between those students who, without exam exemption, had an average grade (5) and a higher percentage of students passing the exam. It is concluded that the use of the total virtuality applied in the year 2020 for the ESFUNO course did not have a negative impact on the approval rate, either at the exemption level or at the approval level in the first and second period of exam.
O presente trabalho mostra os resultados de um estudo diagnóstico sobre o efeito da aplicação de uma metodologia de ensino totalmente virtual para o curso ESFUNO da Faculdade de Enfermagem no contexto da pandemia Covid-19. Realizou-se um estudo observacional descritivo e analítico comparando o desempenho acadêmico entre as gerações de 2019 e 2020 através da comparação de proporções. Se sistematizaram os dados do desempenho estudantil para aprovação direta do curso ESFUNO e os dois primeiros períodos das provas a partir da finalização do curso desenvolvidos após a implementação do Plano 2016. Pelos dados obtidos, observou-se que houve predomínio da aprovação direta do curso, com uma porcentagem de 56% para o ano de 2019 e de 79 % para o ano de 2020, sendo este um aumento significativo (p<0.05). Observou-se, ainda, no ano de 2020 um aumento significativo da desvinculação do curso quando comparado ao ano de 2019 (27 % e 19 %, respectivamente) (p<0.05). A proporção de estudantes que passaram na prova de ESFUNO aumentou significativamente no segundo período para o ano de 2019 (p<0.05), porém não se observou o mesmo no ano de 2020 (p>0.05). Ao comparar a taxa de aprovação no primeiro período de recuperação entre a geração que cursou no ano de 2019 com a geração que cursou no ano de 2020, se observou um aumento significativo para o ano de 2020 (p<0.05). Finalmente, foi observado que no ano de 2020 houve uma associação positiva entre aqueles alunos que não obtiveram aprovação direta, mas tiveram nota média (5) e maior percentual de aprovação. Conclui-se que a utilização da modalidade totalmente virtual aplicada no ano de 2020 para realização do curso ESFUNO não teve um impacto negativo sobre os níveis de aprovação do mesmo, seja no nível de aprovação direta, como no nível de aprovação no primeiro e segundo períodos de provas.
Subject(s)
Humans , Students, Nursing , Universities , Uruguay , Education, Distance , Education, Nursing , Academic Performance , COVID-19ABSTRACT
Austrolebias annual fishes exhibit cell proliferation and neurogenesis throughout life. They withstand extreme environmental changes as their habitat dries out, pressuring nervous system to adapt. Their visual system is challenged to adjust as the water becomes turbid. Therefore, this study focused on how change in photic environment can lead to an increased cell proliferation in the retina. We administered 5-chloro-2'- deoxyuridine (CldU) and 5-iodo-2'-deoxyuridine (IdU) at different temporal windows to detect cell proliferation in natural light and permanent darkness. Stem/progenitor cells were recognized as IdU+/CldU + nuclei co-labeled with Sox2, Pax6 or BLBP found in the ciliary marginal zone (CMZ). The expression pattern of BLBP + glial cells and ultrastructural analysis indicates that CMZ has different cell progenitors. In darkness, the number of dividing cells significantly increased, compared to light conditions. Surprisingly, CMZ IdU+/CldU + cell number was similar under light and darkness, suggesting a stable pool of stem/progenitor cells possibly responsible for retinal growth. Therefore, darkness stimulated cell progenitors outside the CMZ, where Müller glia play a crucial role to generate rod precursors and other cell types that might integrate rod-dependent circuits to allow darkness adaptation. Thus, the Austrolebias fish retina shows great plasticity, with cell proliferation rates significantly higher than that of brain visual areas.
ABSTRACT
Our previous studies demonstrated that Austrolebias charrua annual fish is an excellent model to study adult brain cell proliferation and neurogenesis due to the presence of active and fast neurogenesis in several regions during its short lifespan. Our main goal was to identify and localize the cells that compose the neurogenic areas throughout the Austrolebias brain. To do this, we used two thymidine halogenated analogs to detect cell proliferation at different survival times: 5-chloro-2'-deoxyuridine (CldU) at 1day and 5-iodo-2'-deoxyuridine (IdU) at 30days. Three types of proliferating cells were identified: I - transient amplifying or fast cycling cells that uptake CldU; II - stem cells or slow cycling cells, that were labeled with both CldU and IdU and did not migrate; and III - migrant cells that uptake IdU. Mapping and 3D-reconstruction of labeled nuclei showed that type I and type II cells were preferentially found close to ventricle walls. Type III cells appeared widespread and migrating in tangential and radial routes. Use of proliferation markers together with Vimentin or Nestin evidenced that type II cells are the putative stem cells that are located at the ventricular lumen. Double label cells with IdU+ and NeuN or HuC/D allowed us identify migrant neurons. Quantitation of labeled nuclei indicates that the proportion of putative stem cells is around 10% in all regions of the brain. This percentage of stem cells suggests the existence of a constant brain cell population in Austrolebias charrua that seems functional to the maintainance of adult neurogenesis.
