Cytotoxicity of Environmentally Relevant Concentrations of Aluminum in Murine Thymocytes and Lymphocytes

The effects of low concentrations of aluminum chloride on thymocytes and lymphocytes acutely dissociated from young mice were studied using flow cytometry with a DNA-binding dye. We demonstrate a rapid and dose-dependent injury in murine thymocytes and lymphocytes resulting from exposure to aluminum, as indicated by an increase in the entry into the cell of the DNA-binding dye, propidium iodine. A 60-minute exposure to 10 μM AlCl3 caused damage of about 5% of thymocytes, while 50% were injured after 10 minutes at 20 μM. Nearly all thymocytes showed evidence of damage at 30 μM AlCl3 after only 5 minutes of incubation. In lymphocytes, injury was observed at 15 μM AlCl3 and less than 50% of cells were injured after a 60-minute exposure to 20 μM. Injury only rarely proceeded to rapid cell death and was associated with cell swelling. These results suggest that aluminum has cytotoxic effects on cells of the immune system

Dynamics of glutamatergic signaling in the mushroom body of young adult Drosophila

<p>Abstract</p> <p>Background</p> <p>The mushroom bodies (MBs) are paired brain centers located in the insect protocerebrum involved in olfactory learning and memory and other associative functions. Processes from the Kenyon cells (KCs), their intrinsic neurons, form the bulk of the MB's calyx, pedunculus and lobes. In young adult <it>Drosophila</it>, the last-born KCs extend their processes in the α/β lobes as a thin core (α/β cores) that is embedded in the surrounding matrix of other mature KC processes. A high level of L-glutamate (Glu) immunoreactivity is present in the α/β cores (α/βc) of recently eclosed adult flies. In a <it>Drosophila </it>model of fragile X syndrome, the main cause of inherited mental retardation, treatment with metabotropic Glu receptor (mGluR) antagonists can rescue memory deficits and MB structural defects.</p> <p>Results</p> <p>To address the role of Glu signaling in the development and maturation of the MB, we have compared the time course of Glu immunoreactivity with the expression of various glutamatergic markers at various times, that is, 1 hour, 1 day and 10 days after adult eclosion. We observed that last-born α/βc KCs in young adult as well as developing KCs in late larva and at various pupal stages transiently express high level of Glu immunoreactivity in <it>Drosophila</it>. One day after eclosion, the Glu level was already markedly reduced in the α/βc neurons. Glial cell processes expressing glutamine synthetase and the Glu transporter dEAAT1 were found to surround the Glu-expressing KCs in very young adults, subsequently enwrapping the α/β lobes to become distributed equally over the entire MB neuropil. The vesicular Glu transporter DVGluT was detected by immunostaining in processes that project within the MB lobes and pedunculus, but this transporter is apparently never expressed by the KCs themselves. The NMDA receptor subunit dNR1 is widely expressed in the MB neuropil just after eclosion, but was not detected in the α/βc neurons. In contrast, we provide evidence that DmGluRA, the only <it>Drosophila </it>mGluR, is specifically expressed in Glu-accumulating cells of the MB α/βc immediately and for a short time after eclosion.</p> <p>Conclusions</p> <p>The distribution and dynamics of glutamatergic markers indicate that newborn KCs transiently accumulate Glu at a high level in late pupal and young eclosed <it>Drosophila</it>, and may locally release this amino acid by a mechanism that would not involve DVGluT. At this stage, Glu can bind to intrinsic mGluRs abundant in the α/βc KCs, and to NMDA receptors in the rest of the MB neuropil, before being captured and metabolized in surrounding glial cells. This suggests that Glu acts as an autocrine or paracrine agent that contributes to the structural and functional maturation of the MB during the first hours of <it>Drosophila </it>adult life.</p

Construyendo horizontes universitarios

Nuestro proyecto puede ser definido a partir de una problematización sobre la educación pública y sus posibilidades de realización en el contexto educativo en la ciudad de San Luis. Esta última avanzada del capitalismo y sus consecuencias pandémicas no nos han sido indiferentes. A raíz de esto y desde la iniciativa de dos profesorxs de la Facultad de Ciencias Humanas de la UNSL, nos sentimos interpeladxs a participar de un proyecto de extensión universitaria llamado “Construyendo Horizontes Universitarios”. En nuestra formación como educadorxs de distintas disciplinas, de comunicadorxs del tramado social, nos convocamos a pensar sobre la dificultad e imposibilidad de las juventudes de los sectores populares para acceder a la educación superior. Partimos de la idea que el acceso a la educación superior es un derecho humano, nos cuestionamos sobre cómo se construye efectivamente ese derecho, cuáles son las prácticas que lo vuelven real y cuál es nuestro rol en todo ésto. Sabemos que el acceso no alcanza, que el ingreso no lo es todo, por lo que empezamos a elaborar algunas estrategias pedagógicas que pudieran facilitar el ingreso y la permanencia en la Universidad. En función de esto, planificamos grupos de discusión con estudiantes de escuelas de barrios periféricos de la Ciudad de San Luis. De esos grupos de discusión surgieron problemáticas que, bajo la consigna de “rascar donde pica”, se transformaron en los talleres en los que actualmente estamos trabajando. Sería apresurado sacar conclusiones en este momento, pero sí podemos decir con total seguridad que una serie de caminos y diálogos se han construido desde la extensión universitaria hacia los barrios de la Ciudad, esperando que quienes así lo decidan, puedan incorporarse de la forma más amena posible a la vida universitaria.Universidad Nacional de La Plat