Metallothionein expression in the central nervous system in response to chronic heavy metal exposure: possible neuroprotective mechanism.

It has been reported that volcanoes release several tonnes of mercury per year among other heavy metals through eruptions, fumaroles, or diffuse soil degassing. Since a high percentage of the world's population lives in the vicinity of an active volcano, the aim of this study is to evaluate the accumulation of these metals in the central nervous system and the presence of cellular mechanisms of heavy metal detoxification such as metallothioneins. To carry out this study, wild mice (Mus musculus) chronically exposed to an active volcanic environment were captured in Furnas village (Azores, Portugal) and compared with those trapped in a reference area (Rabo de Peixe, Azores, Portugal). On the one hand, the heavy metal load has been evaluated by analyzing brain and cerebellum using ICP-MS and a mercury analyzer and on the other hand, the presence of metallothionein 2A has been studied by immunofluorescence assays. Our results show a higher load of metals such as mercury, cadmium and lead in the central nervous system of exposed mice compared to non-exposed individuals and, in addition, a higher immunoreactivity for metallothionein 2A in different areas of the cerebrum and cerebellum indicating a possible neuroprotection process.

Reactive astrogliosis in the dentate gyrus of mice exposed to active volcanic environments.

Air pollution has been associated with neuroinflammatory processes and is considered a risk factor for the development of neurodegenerative diseases. Volcanic environments are considered a natural source of air pollution. However, the effects of natural source air pollution on the central nervous system (CNS) have not been reported, despite the fact that up to 10% of the world's population lives near a historically active volcano. In order to assess the response of the CNS to such exposure, our study was conducted in the island of Sao Miguel (Azores, Portugal) in two different areas: Furnas, which is volcanically active one, and compared to Rabo de Peixe, a reference site without manifestations of active volcanism using Mus musculus as a bioindicator species. To evaluate the state of the astroglial population in the dentate gyrus in both samples, the number of astrocytes was determined using immunofluorescence methods (anti-GFAP and anti-GS). In addition, the astrocytic branches in that hippocampal area were examined. Our results showed an increase in GFAP+ astrocytes and a reduction in GS+ astrocytes in Furnas-exposed mice compared to animals from Rabo de Peixe. In addition, astrocytes in the dentate gyrus of chronically exposed animals exhibited longer branches compared to those residing at the reference site. Thus, reactive astrogliosis and astrocyte dysfunction are found in mice living in an active volcanic environment.

The Health Hazards of Volcanoes: First Evidence of Neuroinflammation in the Hippocampus of Mice Exposed to Active Volcanic Surroundings.

Neuroinflammation is a process related to the onset of neurodegenerative diseases; one of the hallmarks of this process is microglial reactivation and the secretion by these cells of proinflammatory cytokines such as TNFα. Numerous studies report the relationship between neuroinflammatory processes and exposure to anthropogenic air pollutants, but few refer to natural pollutants. Volcanoes are highly inhabited natural sources of environmental pollution that induce changes in the nervous system, such as reactive astrogliosis or the blood-brain barrier breakdown in exposed individuals; however, no neuroinflammatory event has been yet defined. To this purpose, we studied resting microglia, reactive microglia, and TNFα production in the brains of mice chronically exposed to an active volcanic environment on the island of São Miguel (Azores, Portugal). For the first time, we demonstrate a proliferation of microglial cells and an increase in reactive microglia, as well an increase in TNFα secretion, in the central nervous system of individuals exposed to volcanogenic pollutants.

Chronic exposure to volcanic gaseous elemental mercury: using wild Mus musculus to unveil its uptake and fate.

Volcanoes are a natural source of gaseous elemental mercury (GEM) (Hg0). Monitoring GEM releases of volcanic origin has been widely studied; however, few studies have been performed about the biomonitoring of species exposed to GEM, rendering an unknown risk to the worldwide populations living in the vicinity of an active volcano. In this pilot study, we used Mus musculus as a bioindicator species to understand to what extent lungs are the main route of mercury uptake in populations chronically exposed to active volcanic environments. Autometallographic silver protocol was used to detect mercury deposits in the histological lung slides. Abundant mercury deposits were found in the lungs of specimens captured at the site with volcanic activity (Furnas Village, S. Miguel Island-Azores). The presence of mercury in the lungs could represent not only hazardous effects to the lung itself but also to other tissues and organs, such as brain and kidneys. This study confirms that the main uptake route for GEM is the lungs and that, even at very low concentrations in the environment, a chronic exposure to Hg0 results in its bioaccumulation in the lung tissue. These results reinforce that biomonitoring studies should be combined with monitoring classical approaches in order to better characterize the risks of exposure to Hg0 in volcanic environments.

First record on mercury accumulation in mice brain living in active volcanic environments: a cytochemical approach.

The health effects of mercury vapor exposure on the brain in volcanic areas have not been previously addressed in the literature. However, 10% of the worldwide population inhabits in the vicinity of an active volcano, which are natural sources of elemental mercury emission. To evaluate the presence of mercury compounds in the brain after chronic exposure to volcanogenic mercury vapor, a histochemical study, using autometallographic silver, was carried out to compare the brain of mice chronically exposed to an active volcanic environment (Furnas village, Azores, Portugal) with those not exposed (Rabo de Peixe village, Azores, Portugal). Results demonstrated several mercury deposits in blood vessels, white matter and some cells of the hippocampus in the brain of chronically exposed mice. Our results highlight that chronic exposure to an active volcanic environment results in brain mercury accumulation, raising an alert regarding potential human health risks. These findings support the hypothesis that mercury exposure can be a risk factor in causing neurodegenerative diseases in the inhabitants of volcanically active areas.

Occurrence of Volcanogenic Inorganic Mercury in Wild Mice Spinal Cord: Potential Health Implications.

Mercury accumulation has been proposed as a toxic factor that causes neurodegenerative diseases. However, the hazardous health effects of gaseous elemental mercury exposure on the spinal cord in volcanic areas have not been reported previously in the literature. To evaluate the presence of volcanogenic inorganic mercury in the spinal cord, a study was carried out in São Miguel island (Azores, Portugal) by comparing the spinal cord of mice exposed chronically to an active volcanic environment (Furnas village) with individuals not exposed (Rabo de Peixe village), through the autometallographic silver enhancement histochemical method. Moreover, a morphometric and quantification analysis of the axons was carried out. Results exhibited mercury deposits at the lumbar level of the spinal cord in the specimens captured at the site with volcanic activity (Furnas village). A decrease in axon calibre and axonal atrophy was also observed in these specimens. Given that these are relevant hallmarks in the neurodegenerative pathologies, our results highlight the importance of the surveillance of the health of populations chronically exposed to active volcanic environments.

Efecto de un programa de refuerzo motriz en alumnado con dificultades motrices y/o sociales / Efeito de um programa de reforço motor sobre os estudantes com dificuldades motoras e/ou sociais / Effect of a motor reinforcement programme in students with motor and/or social difficulties

El objetivo del presente estudio fue mejorar la competencia motriz y las relaciones sociales en alumnado con dificultades de coordinación y/o sociales a través de un programa integral de refuerzo motriz. Para ello, el estudio se dividió en cuatro fases. En la primera fase se seleccionaron, de entre los 60 niños participantes de tercer curso de Educación infantil, aquellos susceptibles de sufrir dificultades de movimiento y/o déficit en sus relaciones sociales, tras la aplicación de una serie de pruebas filtro. En la segunda y tercera fase se evaluó la competencia motriz, mediante la Batería de evaluación del movimiento para niños (MABC-2) y se implementó un programa de alfabetización física orientado al desarrollo de las habilidades motrices básicas para, finalmente, en la cuarta fase, comprobar si se había producido alguna mejora en la competencia motriz y en las relaciones sociales del alumnado participante. Tras la aplicación de la intervención se comprobaron mejoras significativas entre las medias pre y post en la dimensión equilibrio, puntería y atrape y puntuación global, además de una mejora significativa en amigo positivo. Estos resultados invitan a seguir trabajando en esta línea para favorecer un adecuado desarrollo de los alumnos de la etapa de infantil, tanto a nivel motriz como a nivel social. (AU)

The goal of this study was to improve motor competence and social relationships among students with coordination and / or social difficulties, through an integrative reinforcement program, from motor skills. For that purpose, the study was divided into four phases. In the first one, from among 60 children participating in the third year of Early Childhood Education, those who were susceptible to suffer difficulties with movement and / or deficits in their social relationships were selected, after having applied different filter tests. In the second and third phase, motor competence was evaluated through the Children's Movement Assessment Battery (MABC-2) and a physical literacy program was implemented aimed at the development of basic motor skills. Finally, in the fourth phase, it was checked whether there had been any improvement in the motor competence and social relations of the participating students. After intervention, significant improvements were found between the pre and post averages in the dimension balance, aim and catch and overall score, plus a significant improvement in positive friend. These results invite us to continue working to promote the adequate development among students in the infant stage, both at the motor and social levels. (AU)

Esta pesquisa tem como objetivo melhorar a competência motora e as relações sociais em estudantes com dificuldades de coordenação e/ou sociais, por meio de um programa abrangente de reforço das habilidades motoras. Para isso, o estudo está dividido em quatro fases. Na primeira, foram selecionados entre os 60 alunos participantes do terceiro curso de educação infantil, aqueles suscetíveis de apresentar dificuldades de movimento e/ou de relações sociais, após a aplicação de uma série de testes de filtragem. Na segunda e terceira fases, avaliou-se a competência motora por meio da Bateria de Avaliação de Movimentos para Crianças (Mabc-2) e se implementou um programa de alfabetização física orientada ao desenvolvimento das habilidades motoras básicas; para, finalmente, na quarta fase, comprovar se houve melhora na competência motora e nas relações sociais dos participantes. Após a aplicação da intervenção, melhorias significativas entre as médias pré e post na dimensão equilíbrio, pontaria e captura e pontuação global , bem como uma melhoria significativa em amigo positivo. O que nos sugere a continuar trabalhando nesta linha para promover o desenvolvimento adequado dos alunos na fase infantil, tanto no nível motor quanto no social. (AU)

Opinión del alumnado sobre el uso de WhatsApp en el aprendizaje de la histología durante COVID-19 / Students' views about using WhatsApp for learning histology during COVID-19

RESUMEN: La pandemia de COVID-19 ha provocado importantes retos para el sistema de enseñanza superior. Las medidas adoptadas para prevenir la transmisión comunitaria han desplazado la enseñanza presencial frente a la virtual. Las nuevas prácticas de enseñanza y aprendizaje adoptadas han planteado la necesidad de reforzar la dimensión social del aprendizaje. En este contexto, hemos implementado el uso de WhatsApp para interactuar y compartir contenidos académicos en un pequeño grupo de estudiantes de un curso de Histología. El objetivo de este estudio fue evaluar la percepción de los estudiantes sobre la eficacia de esta red social para facilitar la comunicación y compartir información educativa, su utilidad en el aprendizaje y su capacidad para modificar la dimensión afectiva durante el proceso de enseñanza-aprendizaje. Los resultados mostraron que los estudiantes tenían una actitud positiva hacia el uso de WhatsApp en el entorno de aprendizaje, de modo que facilitó la comunicación y la cohesión del grupo, favoreció el aprendizaje y redujo la ansiedad ante la evaluación. Así, las redes sociales deberían integrarse en el proceso de aprendizaje teniendo en cuenta las características del alumnado.

SUMMARY: The COVID-19 pandemic has caused significant challenges for the higher education system. The adopted measures to prevent community transmission have shifted face-to-face teaching to virtual education. The new adopted teaching and learning practices have raised the need for reinforcing the social dimension of learning. In this context, we have implemented the use of WhatsApp to interact and sharing academic contents in a small group of students in a Histology course. The aim of this study was to evaluate the students' perceptions about the effectiveness of this social network in facilitating communication and sharing educational information, its usefulness in learning, and its ability to modify the affective dimension during the teaching- learning process. The results showed that students had a positive attitude towards the use of WhatsApp in the learning environment, so that it facilitated communication and group cohesion, favored learning and reduced anxiety in the face of evaluation. Thus, social networks must be integrated in learning process considering students' characteristics.

Comparative analysis of retinal ganglion cell topography and behavioral ecology in Australian marsupials / Análisis comparativo de la topografía de las células ganglionares de la retina y ecología del comportamiento en marsupiales australianos

SUMMARY: The retina of vertebrates shows adaptations to the visual environment in which they evolve. Thus, there exists a relationship between the topographic distribution of retinal cells, the adaptive strategies employed, and habitat, so that, analyses of retinal ganglion cell topography provide information about the behavioral ecology of a species. Although these relationships are well documented in many vertebrates, including mammals, for species within the marsupial order, they are not well understood. However, marsupials represent an ideal group for comparative analyses of interspecific variations in the mammalian visual system because they contain species that vary in both lifestyle and habitat preference. In this paper the interspecific variation in retinal ganglion cell topography in 13 species of Australian marsupials is reviewed. The species that live in open habitats have well-defined elongated visual streaks. In contrast, forest-dwelling marsupials have poorly defined visual streaks and a more radially symmetrical arrangement of retinal ganglion cell (RGC) isodensity contours. However, the organization and degree of elongation of the visual streak varies considerably among species. The results indicate that the apparent interspecific variation is associated with activity pattern and habitat as opposed to the phylogenetic relationships among species.

RESUMEN: La retina de los vertebrados muestra adaptaciones al entorno visual en el que evolucionan. Por lo tanto, existe una relación entre la distribución topográfica de las células de la retina, las estrategias de adaptación empleadas y el hábitat, por lo que los análisis de la topografía de las células ganglionares de la retina proporcionan información sobre la ecología del comportamiento de una especie. Aunque estas relaciones están bien documentadas en muchos vertebrados, incluidos los mamíferos, para especies dentro del orden marsupiales, no se conocen bien. Sin embargo, los marsupiales representan un grupo ideal para análisis comparativos de variaciones interespecíficas en el sistema visual de mamíferos porque contienen especies que varían tanto en el estilo de vida como en la preferencia del hábitat. En este trabajo se revisa la variación interespecífica en la topografía de células ganglionares de la retina en 13 especies de marsupiales australianos. Las especies que viven en hábitats abiertos tienen bandas visuales alargadas bien definidas. Por el contrario, los marsupiales que habitan en el bosque tienen rayas visuales mal definidas y una disposición más simétrica radialmente de los contornos de isodensidad de los CGR. Sin embargo, la organización y el grado de elongación de la banda visual varía considerablemente entre las especies. Los resultados indican que la aparente variación interespecífica está asociada con el patrón de actividad y el hábitat en oposición a las relaciones filogenéticas entre las especies.

Apoptosis durante el desarrollo embrionario de la retina de tortuga (Trachemys scripta elegans) / Apoptosis in turtle embryonic retina (Trachemys scripta elegans)

La apoptosis o muerte celular programada es un proceso que ocurre durante el desarrollo del sistema nervioso. El objetivo de este estudio fue observar los patrones de apoptosis que se producen durante el desarrollo embrionario de la retina, desde el estadio S16 al momento del nacimiento, mediante miscoscopía óptica y electrónica. Se utilizaron retinas de embriones de tortuga. Nuestros datos muestran que los primeros signos de apoptosis comienzan en el estadio S16, en la capa nuclear interna y alcanzan su máxima densidad tanto en la capa nuclear interna como en la capa de células ganglionares en S20, para extinguirse, prácticamente, en el momento del nacimiento. Por otra parte, la apoptosis sigue un gradiente centro-periferia.

Apoptosis or programmed cell death is a process that occurs during development of the nervous system. The aim of this study was to observe the patterns of apoptosis that occur during embryonic development of the retina from the stage S16 at birth, by light and electron miscoscopia. Turtle embryonic retinas were used for the study. Our data show that the first signs of apoptosis begins at stage S16 in the inner nuclear layer and reaches maximum density both in the inner nuclear layer and the ganglion cell layer in S20 until they practically disappear at the time of birth. Furthermore, apoptosis follows a gradient center-periphery.

Características morfológicas de la retina del calderón común (Globicephala melas; traill, 1809) y su relación con el hábitat / Morphological characteristics of pilot whales retina (Globicephala melas; traill, 1809) and their relationship to habitat

Existe una estrecha relación entre las características morfológicas de los sistemas sensoriales, su funcionamiento y el hábitat al que están adaptados los organismos. En este sentido, de todos los mamíferos marinos estudiados, los cetáceos son los que más profundamente han modificado su estructura y fisiología ocular por su estrecha adaptación a una vida exclusivamente acuática. Para aportar más datos a la literatura, el objetivo de este trabajo es describir morfológicamente la retina de la ballena piloto a través de técnicas de microscopia óptica, con el fin de relacionarla con su adaptación al medio acuático. Nuestros datos muestran que la retina de Globicephala melas se organiza de acuerdo al mismo plan básico de los vertebrados. Tiene un grosor medio alrededor de 330±23 µm en las zonas de alta densidad de células ganglionares y 175±2 µm en la zona periférica. La capa de los fotorreceptores se corresponde con el 45% del grosor de la retina total. Presenta largos segmentos externos. La capa más característica de cetáceos en general y de Globicephala melas en particular, es la capa de células ganglionares. Su grosor, de 77,76±37,26 siendo la más variable de toda la retina. Esta capa presenta baja densidad celular pero tamaños excepcionalmente grandes, de 10 a 75 µm (promedio de 33,5 µm), denominadas células ganglionares gigantes.

There is a close relationship between morphological features of sensory systems, their function and habitat to which these organisms are adapting. In this sense, of all marine mammals that have been studied, cetaceans are the ones that have profoundly changed structure and ocular physiology in their adaptation to an exclusively aquatic life. To add further data to the literature, the aim of this paper is to describe morphologically the retina of the pilot whale through optical microscopy and relate their adaptation to the aquatic environment. Our data show that the retina of the long-finned pilot whale is organized according to the same basic plan of vertebrates. It has an average thickness of about 330±23 microns in areas of high ganglion cell density of 175±2 microns in the peripheral zone. Photoreceptor layer corresponds to 45% of total thickness of the retina and has long outer segments. The most significant characteristic of cetaceans in general and long-finned pilot whale in particular, is the ganglion cell layer. Thickness of 77.76±37.26 being the most variable of the entire retina. This layer has a low density but exceptionally large cell size of 10 to 75 microns (average of 33.5 microns), known as giant ganglion cells.