Contado en primera persona: los pueblos se vacían... y las ciudades se llenan

Resumen En la década de 1950 las zonas males comienzan a experimentar una transformación profunda. Muchas regiones de la península se van quedando vacías, mientras ciudades como Madrid, Barcelona, Bilbao, empiezan a desarrollar una zona urbana a su alrededor que las convierten en las áreas metropolitanas que son en la actualidad

Diseño de trabajos basado en aprendizaje por experiencias. Una experiencia concreta

Uno de los objetivos del Espacio Europeo de Educación Superior (EEES) es convertir al estudiante en una parte activa del aprendizaje. Una forma habitual de conseguir este objetivo consiste en la realización de actividades diversas durante el curso. Una actividad bastante común es la elaboración de trabajos de carácter teórico-práctico fuera del aula. Aunque la utilización de esta técnica permite el desarrollo de algunas competencias relevantes en la mayoría de los títulos de grado, su efectividad está sujeta a su diseño. En nuestra experiencia, ciertos planteamientos conducen a entregas de trabajos que principalmente se componen de listados, enumeraciones y/o definiciones, sin profundizar en los aspectos más relevantes ni en la aplicabilidad práctica de los conceptos que se presentan. Por el contrario, mediante un diseño más adecuado, es posible lograr un incremento en la motivación del alumnado, la consecución de objetivos de aprendizaje que cubran un espectro más amplio de niveles cognitivos y el desarrollo de competencias distintas al trabajo autónomo. En este artículo, describimos una caso práctico en el que hemos reformulado el planteamiento de algunas actividades utilizando los principios del aprendizaje por experiencias, y hemos analizado los efectos de los cambios. El nuevo diseño ha producido un aumento de la motivación, una mayor profundización en los temas, una participación significativamente más alta y la entrega de trabajos de mayor calidad.SUMMARY -- The European Higher Education Area (EHEA) encourages the use of active learning approaches. One common way to involve the student in the learning process is by incorporating a wide and diverse range of activities in each course. One such activity are course works that students have to solve outside the classroom. Although this technique allows the development of some competences which are relevant to most degrees, academic results depend on the activity design. According to our experience, some activities lead to resolutions that are mainly composed of listings, enumerations and/or definitions, with neither a further investigation on relevant aspects nor the practical application of the concepts presented. On the contrary, a more adequate design makes it possible to increase student motivation, achieve learning objectives that cover other cognitive levels, and develop competences other than autonomous work. In this article, we describe a practical case study in which some activities have been reformulated by using the principles of experiential learning. The analysis of the results show that the new design has increased the student’s motivation and effort, yielded a significantly higher participation and led to higher quality works.Peer Reviewe

Osteoblastoma del sacro. A propósito de dos casos clínicos.

El osteoblastoma es un tumor óseo primitivo de frecuente localización en los elementos posteriores de la columna vertebral, aunque raro en el sacro. Se presentan dos osteoblastomas del sacro, con un seguimiento medio de ocho años, tratados mediante resección intralesional que, sin morbilidad, deparó un excelente resultado. El curetaje sería un procedimiento de resección válido en osteoblastomas sacros no agresivos, si bien obliga a un seguimiento prolongado del paciente para vigilar la posibilidad de recidivas locales.Osteoblastoma is a primary neoplasm of bone fre- quently located in the posterior elements of the spine, alt- hough rarely affecting the sacrum. Two cases in this location are reported, with a mean follow-up of eight years, treated with an intralesional resection that, without any morbidity, has provided an excellent result. Curettage should be a valid re- section procedure for nonagressive osteoblastomas of the sacrum, although it makes necessary a long follow-up in or- der to watch over the possibility of a local recurrence

Tumores óseos del pie

El manejo de los tumores óseos es difícil, debido a sus diferentes formas y comportamientos y a su baja incidencia. El pie no escapa a este axioma, ya que los tumores en esta región anatómica son particularmente infrecuentes y pueden mostrar un comportamiento clínico y radiológico diferente del que evidencian en otras regiones del esqueleto. Los autores revisan, en primer lugar, los aspectos generales de los tumores óseos del pie, considerando su epidemiología, el proceder diagnóstico y pronóstico y las opciones terapéuticas, para luego pasar a examinar las particularidades regionales e histológicas de estas neoplasias en relación con su tratamiento.The management of bone tumours is difficult, both because of their varying forms and behaviours and because of their low incidence. The foot is no exception to this axiom, as tumours in this particular anatomic region are particularly infrequent and may exhibit a clinical and radiological behaviour completely at variance to that in other skeletal regions. The authors first review the general aspects of the bobe tumours of the foot, considering their epidemiology, the diagnostic procedure and prognosis and the therapeutic options, and then examine the regional and histologic peculiaritiesof these neoplasms as related to their therapeutic management

Impact of sperm DNA damage and oocyte-repairing capacity on trout development

Palabras clave extraídas del título[EN] Zygotic repair of paternal DNA is essential during embryo development. In spite of the interest devoted to sperm DNA damage, its combined effect with defect-repairing oocytes has not been analyzed. Modification of the breeding season is a common practice in aquaculture. This practice reduces developmental success and could affect the both factors: sperm DNA integrity and oocyte repair capacity. To evaluate the maternal role, we analyzed the progeny outcome after fertilizing in-season trout oocytes with untreated and with UV-irradiated sperm. We also analyzed the offspring obtained out of season with untreated sperm. The analysis of the number of lesions in 4 sperm nuclear genes revealed an increase of 1.22–11.18 lesions/10 kb in out-of-season sperm, similar to that obtained after sperm UV irradiation (400 µW/cm25 min). Gene expression showed in out-of-season oocytes the overexpression of repair genes (ogg1, ung, lig3, rad1) and downregulation of tp53, indicating an enhanced repairing activity and reduced capacity to arrest development upon damage. The analysis of the progeny in out-of-season embryos revealed a similar profile tolerant to DNA damage, leading to a much lower apoptotic activity at organogenesis, lower hatching rates and increased rate of malformations. The effects were milder in descendants from in-season-irradiated sperm, showing an enhanced repairing activity at epibolia. Results point out the importance of the repairing machinery provided by the oocyte and show how susceptible it is to environmental changes. Transcripts related to DNA damage signalization and repair could be used as markers of oocyte qualitySIThis work was supported by the Spanish Ministry of Economy and Competitiveness (project AGL2011-27787

Male exposure to bisphenol a impairs spermatogenesis and triggers histone hyperacetylation in zebrafish testes

[EN] Bisphenol A (BPA) is an endocrine disruptor whose ubiquitous presence in the environment has been related with impairment of male reproduction. BPA can cause both transcriptomic and epigenetic changes during spermatogenesis. To evaluate the potential effects of male exposure to BPA, adult zebrafish males were exposed during spermatogenesis to doses of 100 and 2000 μg/L, which were reported in contaminated water bodies and higher than those allowed for human consumption. Fertilization capacity and survival at hatching were analysed after mating with untreated females. Spermatogenic progress was analysed through a morphometrical study of testes and apoptosis was evaluated by TUNEL assay. Testicular gene expression was evaluated by RT-qPCR and epigenetics by using ELISA and immunocytochemistry. In vitro studies were performed to investigate the role of Gper. Chromatin fragmentation and the presence of transcripts were also evaluated in ejaculated sperm. Results on testes from males treated with the highest dose showed a significant decrease in spermatocytes, an increase in apoptosis, a downregulation of ccnb1 and sycp3, all of which point to an alteration of spermatogenesis and to meiotic arrest and an upregulation of gper1 and esrrga receptors. Additionally, BPA at 2000 μg/L caused missregulation of epigenetic remodelling enzymes transcripts in testes and promoted DNA hypermethylation and H3K27me3 demethylation. BPA also triggered an increase in histone acetyltransferase activity, which led to hyperacetylation of histones (H3K9ac, H3K14ac, H4K12ac). In vitro reversion of histone acetylation changes using a specific GPER antagonist, G-36, suggested this receptor as mediator of histone hyperacetylation. Males treated with the lower dose only showed an increase in some histone acetylation marks (H3K14ac, H4K12ac) but their progeny displayed very limited survival at hatching, revealing the deleterious effects of unbalanced paternal epigenetic information. Furthermore, the highest dose of BPA led to chromatin fragmentation, promoting direct reproductive effects, which are incompatible with embryo developmentSIThis work was supported by the Spanish Ministry of Economy and Competitiveness (project AGL2014-53167-C3-3-R), Junta de Castilla y León (Spain) (EDU/1083/2013), the Fondo Social Europeo and by an EMBO Short-Term Fellowship to SG

Tolerance to paternal genotoxic damage promotes survival during embryo development in zebrafish (Danio rerio)

[EN] Spermatozoa carry DNA damage that must be repaired by the oocyte machinery upon fertilization. Different strategies could be adopted by different vertebrates to face the paternal genotoxic damage. Mammals have strong sperm selection mechanisms and activate a zygotic DNA damage response (DDR) (including cell cycle arrest, DNA repair and alternative apoptosis) in order to guarantee the genomic conformity of the reduced progeny. However, external fertilizers, with different reproductive strategies, seem to proceed distinctively. Previous results from our group showed a downregulation of apoptotic activity in trout embryos with a defective DNA repairing ability, suggesting that mechanisms of tolerance to damaged DNA could be activated in fish to maintain cell survival and to progress with development. In this work, zebrafish embryos were obtained from control or UV-irradiated sperm (carrying more than 10% of fragmented DNA but still preserving fertilization ability). DNA repair (γH2AX and 53BP1 foci), apoptotic activity, expression of genes related to DDR and malformation rates were analyzed throughout development. Results showed in the progeny from damaged sperm, an enhanced repairing activity at the mid-blastula transition stage that returned to its basal level at later stages, rendering at hatching a very high rate of multimalformed larvae. The study of transcriptional and post-translational activity of tp53 (ZDF-GENE-990415-270) revealed the activation of an intense DDR in those progenies. However, the downstream pro-apoptotic factor noxa (ZDF-GENE-070119-3) showed a significant downregulation, whereas the anti-apoptotic gene bcl2 (ZDF-GENE-051015-1) was upregulated, triggering a repressive apoptotic scenario in spite of a clear genomic instability. This repression can be explained by the observed upregulation of p53 isoform Δ113p53, which is known to enhance bcl2 transcription. Our results showed that tp53 is involved in DNA damage tolerance (DDT) pathways, allowing the embryo survival regardless of the paternal DNA damage. DDT could be an evolutionary mechanism in fish: tolerance to unrepaired sperm DNA could introduce new mutations, some of them potentially advantageous to face a changing environmentSIThis work was supported by Ministerio de Economı́a y Competitividad (AGL2011- 27787 and AGL2014-53167

Distribution of DNA damage in the sperm nucleus: A study of zebrafish as a model of histone-packaged chromatin

[EN] Reproductive defects can occur when the integrity of the male gamete genome is affected. Sperm chromatin is not homogeneous, having relaxed regions which are more accessible to the transcription machinery in the embryo, and thought to be specially sensitive to DNA damage. The level of damage in specific genes located in these sensitive regions could represent an early biomarker of damage. Our objective is to test the hypothesis that these more relaxed regions show greater susceptibility to damage in zebrafish, a species lacking protamines and whose sperm chromatin is compacted with histones. After sperm UV irradiation, treatment with H2O2 and cryopreservation, global chromatin fragmentation was evaluated using the TUNEL assay, and the number of lesions per 10 Kb in specific genes (hoxa3a, hoxb5b, sox2, accessible for early transcription and rDNA 18S and rDNA 28S) was quantified by using a qPCR approach. Additionally, oxidative damage within the sperm nucleus and the potential colocalization of this injury with histone H3 and TOPO IIα+β were located by using immunofluorescence. UV irradiation produced the highest degree of fragmentation (p = 0.041) and the highest number of lesions per 10 Kb in all the genes, but no differences were observed in sensitivity to damage in the studied genes (ranging from 14.93 to 8.03 lesions per 10 Kb in hoxb5b and 28S, respectively). In contrast, H2O2 and cryopreservation caused varying levels of damage in the analyzed genes which was not related to their accessibility, ranging from 0.00 to 1.65 lesions per 10 Kb in 28S and hoxb5b, respectively, after H2O2 treatment, and from 0.073 to 5.51 in 28S and sox2, respectively, after cryopreservation. Immunodetection near oxidative lesions also revealed different spatial patterns depending on the treatments used, these being mostly homogeneous with UV irradiation or cryopreservation, and peripherally located around the nucleus after H2O2 treatment. Oxidative lesions did not colocalize with histone H3 or TOPO IIα+β thus demonstrating that the relaxed DNA regions associated with these proteins were not more vulnerable to oxidative damage. Results suggest that accessibility of each agent to the nucleus could be the main factor responsible for the distribution of sperm DNA damage rather than the organization of the chromatin. Lesions in these genes important to early embryo development assayed in this study cannot be used as biomarkers of global DNA damageSISpanish Ministry of Economy and Competitiveness (project AGL2011-27787; AGL2014-53167-C3-3-R), Junta de Castilla y León (Spain) (EDU/1083/2013) and the Fondo Social Europe