Problemáticas en las prácticas de lectura y escritura de los estudiantes de posgrado : Su estudio en el ámbito de la carrera del Doctorado en la Facultad de Ciencias Veterinarias

Las carreras de posgrado, tales como las de Especialización, Maestría y Doctorado, han crecido significativamente en las últimas décadas en nuestro país. A pesar del crecimiento en su matrícula y de una mayor oferta de carreras, se ha visto que alrededor del 50% de los estudiantes postergan su culminación o la abandonan. Este fenómeno se ha asociado a que la escritura de la tesis representa, en muchos casos, una de las fases más arduas; proceso que demora más tiempo y en la que suelen presentarse obstáculos difíciles de remontar. En este sentido, la escritura en el nivel de posgrado cobra importancia ya que tiene relación con la adquisición y elaboración de conocimientos disciplinares. Además, la escritura ha comenzado a ser conceptualizada como un elemento central en las prácticas pedagógicas de formación para la investigación, por lo que saber leer y escribir en el posgrado resulta crucial en el proceso de formación de investigadores; y es por medio de la tesis, y de otros textos científicos y académicos, que el tesista forma su identidad como escritor de una determinada comunidad académica y adquiere modos específicos de escritura. En este trabajo final se pretende presentar cuáles son las dificultades relacionadas con los procesos de lectura y escritura durante el desarrollo de la tesis doctoral de la carrera de Doctorado en la Facultad de Ciencias Veterinarias (FCV) de la Universidad Nacional de La Plata (UNLP), y cuáles son los factores a los que se les atribuyen. Mediante una aproximación metodológica de carácter cualitativo, se intentó dar cuenta de las dificultades experimentadas por los estudiantes, en relación con los procesos de lectura y escritura, y se describen los modos en que esas dificultades influyen en el rezago y abandono de la carrera. Para ello, se realizaron entrevistas a los estudiantes de la Carrera de Doctorado de la institución homónima; se consideraron 3 subpoblaciones de estudiantes: regulares, rezagados y aquellos que abandonaron la carrera. Asimismo, se realizaron encuestas a directores de la misma institución con el fin de indagar cómo perciben ellos las dificultades que se presentan en los estudiantes de la carrera. Los resultados muestran que un alto porcentaje de estudiantes ha tenido inconvenientes en el avance de sus planes de tesis debido a la escasa oportunidad de intercambio con sus directores. No obstante, los estudiantes manifestaron (58%) haber buscado apoyo en colegas (que se desempeñan en la misma institución) u otros grupos de trabajos externos a la institución. Resulta llamativo que ninguno de los directores se asume como responsable de guiar a sus tesistas en las prácticas de lectura y escritura, en el marco de la tesis que dirigen; no obstante, han hecho notar (66%) que existe poca oferta de cursos que hacen a esta práctica del doctorando. Finalmente, invito a los involucrados: tesistas, directores y lectores de este trabajo a plantearnos ¿Cuál es el profesional que se intenta formar en la Carrera de Doctorado en Ciencias Veterinarias? ¿Cuáles son las prácticas académicas y científicas que se deben aprender durante la carrera? Es así como, a través de este trabajo final, intento plantear la necesidad de quitarnos el antifaz que suponen algunas prácticas de la tradición pedagógica de esta institución que no contribuyen a una adecuada formación en el nivel, y que nos enfrentemos a un nuevo desafío para desnaturalizar aquello que parece obvio y establecido. El trabajo culmina de este modo con un planteo acerca de cuál es el perfil del egresado de posgrado que debiéramos formar en esta institución, y cuál es el compromiso que se impone a los que formamos docentes investigadores en el posgrado para poder alcanzar satisfactoriamente ese ideal.Facultad de Ciencias Veterinaria

Functional and histopathological changes induced by intraparenchymal injection of kainic acid in the rat cervical spinal cord

Kainic acid (KA) is an analog of the neurotransmitter glutamate and is widely used as an excitotoxic agent to lesion spinal cord networks, thus, providing an interesting model to learn basic mechanisms of spinal cord injury. The present work was aimed to evaluate motor and sensory performance of rats and analyze morphometric parameters of spinal cord neurons after KA injection. Animals were injected either with 0.75, 1 or 1.25. mM of KA at the C5 segment of the cervical spinal cord. Motor and sensory performance of the rats were evaluate at day 0 (before injection) and at days 1, 2, 3 and 7 post-injection (pi) and compared with those of saline-treated and non-operated animals. Animals were sacrificed at each time point for morphometric and histopathological analysis and compared among groups. All KA-treated animals showed a significant impairment at the motor and sensory tests for the ipsilateral forelimb in a concentration-dependent manner in comparison to saline-treated and non-operated animals. Neuronal cell count showed a significant loss of neurons at C4, C5 and C6 cervical segments when compared with those of saline-treated and non-operated animals. The contralateral side of the cervical segments in KA-treated rats remained unchanged. Some improvement at the motor and sensory tests was observed in animals injected with 0.75 and 1. mM KA. Moreover, a mild increase in the neuronal count of the damaged segments was also recorded. The improvement recorded in the motor and sensory tests by day 7 pi may be a consequence of a neuron repairing mechanism triggered soon after the KA excitotoxic effect.Facultad de Ciencias VeterinariasLaboratorio de Análisis de Imágene

Is the vertebral canal prepared to host the aged spinal cord? : A morphometric assessment

Although the interaction between the growing spinal cord and the vertebrae has been widely demonstrated for mammal’s prenatal and early postnatal life, there is no extensive knowledge about this interaction during late postnatal stages. It has been shown that spinal cord injuries are causally related to significant degenerative changes in bone properties. Nevertheless, information about a possible influence of the spinal cord on bone remodelling in adult healthy animals is missing. The aim of this research work was to assess possible morphological changes of the cervical vertebral canal of juvenile and aged rats during the ontogenetic period of adulthood that would justify the suggested influence. Since the spinal cord of rats increases its size with ageing, we analysed whether morphometric changes are occurring in the vertebral canal that would indicate bone remodelling in response to said growth. To this end, we used three complementary morphometric methods to describe the canal of the cervical and the first thoracic vertebrae. Geometric morphometric analyses evidence scarce variation in size and shape between juvenile and aged rats suggesting that, in general terms, the canal morphology of cervical vertebrae is already prepared in early adulthood to host the growing spinal cord. C3 was the only vertebra that showed consistent variation for the variables of canal thickness, perimeter, height and area. This regional variation may be linked to the patterns described for the changing spinal cord.Facultad de Ciencias VeterinariasLaboratorio de Análisis de ImágenesFacultad de Ciencias Naturales y Muse

Fine mapping and epistatic interactions of the vernalization gene VRN-D4 in hexaploid wheat

Wheat vernalization requirement is mainly controlled by the VRN1, VRN2, VRN3, and VRN4 genes. The first three have been cloned and have homoeologs in all three genomes. VRN4 has been found only in the D genome (VRN-D4) and has not been cloned. We constructed a high-density genetic map of the VRN-D4 region and mapped VRN-D4 within a 0.09 cM interval in the centromeric region of chromosome 5D. Using telocentric 5D chromosomes generated from the VRN-D4 donor Triple Dirk F, we determined that VRN-D4 is located on the short arm. The VRN-D4 candidate region is colinear with a 2.24 Mb region on Brachypodium distachyon chromosome 4, which includes 127 predicted genes. Ten of these genes have predicted roles in development but we detected no functional polymorphisms associated to VRN-D4. Two recombination events separated VRN-D4 from TaVIL-D1, the wheat homolog of Arabidopsis vernalization gene VIL1, confirming that this gene is not a candidate for VRN-D4. We detected significant interactions between VRN-D4 and other four genes controlling vernalization requirement (Vrn-A1, Vrn-B1, Vrn-D1, and Vrn-B3), which confirmed that VRN-D4 is part of the vernalization pathway and that it is either upstream or is part of the regulatory feedback loop involving VRN1, VRN2 and VRN3 genes. The precise mapping of VRN-D4 and the characterization of its interactions with other vernalization genes provide valuable information for the utilization of VRN-D4 in wheat improvement and for our current efforts to clone this vernalization gene.EEA Marcos JuárezFil: Kippes, Néstor Fabián. University of California at Davis. Department of Plant Sciences; Estados UnidosFil: Zhu, Jie. Washington State University. USDA-ARS Wheat Genetics, Quality, Physiology and Disease Research Unit; Estados UnidosFil: Chen, Andrew. University of California at Davis. Department of Plant Sciences; Estados UnidosFil: Vanzetti, Leonardo Sebastian. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Marcos Juárez. Grupo Biotecnología y Recursos Genéticos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lukaszewski, Adam. University of California. Department of Botany and Plant Sciences; Estados UnidosFil: Nishida, Hidetaka. Okayama University. Graduate School of Environmental and Life Science; JapónFil: Kato, Kenji. Okayama University. Graduate School of Environmental and Life Science; JapónFil: Dvorak, Jan. University of California at Davis. Department of Plant Sciences; Estados UnidosFil: Dubcovsky, Jorge. University of California at Davies. Department of Plant Sciences; Estados Unidos. Howard Hughes Medical Institute; Estados Unido

Increased number of neurons in the cervical spinal cord of aged female rats

In the brain, specific signaling pathways localized in highly organized regions called niches allow the persistence of a pool of stem and progenitor cells that generate new neurons in adulthood. Much less is known about the spinal cord where a sustained adult neurogenesis is not observed. Moreover, there is scarce information concerning cell proliferation in the adult mammalian spinal cord and virtually none in aging animals or humans. We performed a comparative morphometric and immunofluorescence study of the entire cervical region (C1-C8) in young (5 mo.) and aged (30 mo.) female rats. Serum prolactin (PRL), a neurogenic hormone, was also measured. Gross anatomy showed a significant age-related increase in size of all of the cervical segments. Morphometric analysis of cresyl violet stained segments also showed a significant increase in the area occupied by the gray matter of some cervical segments of aged rats. The most interesting finding was that both the total area occupied by neurons and the number of neurons increased significantly with age, the latter increase ranging from 16% (C6) to 34% (C2). Taking the total number of cervical neurons the age-related increase ranged from 19% (C6) to 51% (C3), C3 being the segment that grew most in length in the aged animals. Some bromodeoxyuridine positive-neuron specific enolase negative (BrdU +-NSE -) cells were observed and, occasionally, double positive (BrdU +-NSE +) cells were detected in some cervical segments of both young and aged rats groups. As expected, serum PRL increased markedly with age. We propose that in the cervical spinal cord of female rats, both maturation of pre-existing neuroblasts and/or possible neurogenesis occur during the entire life span, in a process in which PRL may play a role. © 2011 Portiansky et al.Facultad de Ciencias Veterinaria

Comparative morphometry of the vertebral column of ocelot (Leopardus Pardalis), puma (Puma Concolor) and domestic cat (Felis Catus)

El ocelote y el puma son felinos salvajes nativos de América, particularmente distribuidos en áreas montañosas y boscosas. El conocimiento de la estructura ósea de la columna vertebral es de gran importancia, ya que estas especies se caracterizan por su flexibilidad, lo que les da la agilidad para trepar y saltar con gran ligereza, y moverse rápidamente mientras capturan a su presa. Nuestro objetivo fue realizar un estudio morfométrico comparativo entre la columna vertebral del ocelote, del puma y del gato doméstico. Los estudios morfométricos basados en distancias lineales se realizaron tanto sobre las piezas anatómicas aisladas como sobre su representación digital, en tanto que los análisis de morfometría geométrica se realizaron sobre estas últimas. En este estudio se encontraron similitudes anatómicas entre el puma y el gato, que pueden relacionarse con su asociación filogenética.Ocelot and puma are native American wild cats especially distributed in mountainous and forested areas. Knowledge of the bone structure of the spine is of great importance since these species are characterized by their flexibility, which gives them the agility to climb and jump with great lightness and move quickly while capturing the prey. Our goal was to perform a comparative morphometric study between the spine of ocelot, puma and domestic cat (Felis catus). Morphometric studies (linear distances) were carried out both on the isolated anatomical pieces and on their digital representation, while the geometric morphometric analysis was performed on the latter. In this study, anatomical similarities between puma and cat that may be related to their major phylogenetic relationship were found.Facultad de Ciencias Veterinaria

Effects of an intraparenchymal injection of lidocaine in the rat cervical spinal cord

Lidocaine effects in the spinal cord have been extensively investigated over the years. Although the intrathecal route is usually used to treat insults occurring in the spinal cord, the local delivery drug via intraparenchymal infusions has gained increasing favor for the treatment of some neurodegenerative disorders. The aim of the present study was to evaluate the behavioral and tissue effects of the intraparenchymal injection of different concentrations of lidocaine into the rat cervical spinal cord. Young male Sprague-Dawley rats were intraparenchymally injected with 0.5%, 1% or 2% lidocaine at the C5 segment of the spinal cord. Other rats were injected with saline solution (sham group). Hot plate test was determined at 0, 1, 2, 3, 7 and 14 post-injection (pi) days. Rats of each experimental group were euthanized either at 1, 2, 3, 7 or 14 pi days. Intact animals were used as controls. Sections of the C5 segment were used for histological, immunohistochemical or immunofluorescence analysis. Injection of 0.5% lidocaine did not affect neuronal counting, did not evoke an inflammatory reaction, nor induce astrocyte activation. Therefore, a concentration of 0.5% lidocaine is suggested to promote anti-inflammatory effects after injury.Laboratorio de Análisis de Imágene

Effects of Solanum glaucophyllum toxicity on cell proliferation and apoptosis in the small and large intestine of rabbits

Vitamin D regulates mineral homeostases and enterocyte proliferation and differentiation. Hypervitaminosis D generates changes in cell proliferation, differentiation and apoptosis in several organs. We analysed morphometric parameters and proliferative and apoptotic indices in the intestinal epithelium of rabbits with hypervitaminosis D induced by the chronic treatment with the calcinogenic plant Solanum glaucophyllum. Rabbits were treated for 15 or 30 days. A group was treated for 15 days and led to possible recovery for 30 days. Another group was nutritionally restricted for 30 days. Morphological, morphometric, proliferative and apoptotic changes were found in the treated animals. Mild atrophy and reduced proliferation was found in the jejunum and ileum. Apoptosis increased in the crypts of the ileum and in the superficial epithelium and crypts of the rectum. Most of the alterations were partially recovered. The possible involvement in these changes of the hypervitaminosis D-like state induced by S. glaucophyllum is discussed.Facultad de Ciencias Veterinaria

Modelos experimentales para el estudio de la patogenia de la muerte embrionaria en tricomonosis bovina y herpesvirosis equina

Desde hace mucho tiempo, por razones prácticas, científicas y éticas, se han desarrollado modelos experimentales con animales de laboratorio para su aplicación en investigaciones biomédicas. Los modelos animales se definen como “organismos vivientes con una inherente adquisición natural a procesos patológicos inducidos o espontáneos que, de una u otra manera, semejan el mismo fenómeno ocurrido en el hospedador natural” (Márquez, 1997).\nLos animales de laboratorio son modelos muy convenientes y herramientas útiles para utilizar en el estudio de muchas enfermedades infecciosas. En el caso de medicina veterinaria, en especial cuando se trata de enfermedades de grandes animales, el uso del hospedador natural para estudiar aspectos patogénicos e inmunológicos de una infección, muchas veces se torna dificultoso, tanto por las inconveniencias que genera el manejo de estos animales como por el costo que implica.\nDebido al interés y la complejidad en el estudio de las enfermedades infecciosas, hay una búsqueda en la profundización de los conocimientos del proceso intrínseco de la inmunopatogenia que requiere de la creación de modelos animales alternativos a los hospedadores naturales. El objetivo es generar diseños experimentales confiables y reproducibles, desarrollables en medios controlados en espacios reducidos y con menor costo. Entre las múltiples ventajas que derivan de la utilización de modelos experimentales en el estudio de diferentes enfermedades, se mencionan las siguientes como las más importantes:\n• Conocer la historia natural de la enfermedad, cuya etiología, patogenia, sintomatología y evolución pueden mantenerse en condiciones experimentales, sin la influencia de factores extraños que la modifiquen.\n• Reproducir la enfermedad en forma experimental, casi a voluntad, lo que permite disponer de la casuística necesaria.\n• Realizar estudios fisiopatológicos, desarrollando nuevas técnicas diagnósticas para tal enfermedad.\n• Estudiar las enfermedades en animales endocriados lo que permite un amplio campo de investigación en inmunología, patología y genética, entre otras áreas (Cuba Caparó, 1982).\nEn la selección de la especie utilizada como modelo animal es importante tener en cuenta algunas características generales: a) que permita la transferencia de la información, b) bajo costo y disponibilidad permanentes, c) generalización de los resultados, d) facilidad y adaptabilidad a la manipulación experimental, e) que se pueda contar con un número de animales necesarios para realizar el experimento, f) tiempo de vida, edad en que se alcanza la adultez y generación del número de progenies necesarias en poco tiempo, g) consecuencias ecológicas e implicancias éticas de su uso (Klein, 2000).Incluye las palabras de presentación del proyecto a cargo del Dr. Carlos O. Scoppa

Intracerebroventricular Delivery of Human Umbilical Cord Mesenchymal Stem Cells as a Promising Therapy for Repairing the Spinal Cord Injury Induced by Kainic Acid

Spinal cord injury (SCI) is a common pathological condition that leads to permanent or temporal loss of motor and autonomic functions. Kainic acid (KA), an agonist of kainate receptors, a type of ionotropic glutamate receptor, is widely used to induce experimental neurodegeneration models of CNS. Mesenchymal Stem Cells (MSC) therapy applied at the injured nervous tissue have emerged as a promising therapeutic treatment. Here we used a validated SCI experimental model in which an intraparenchymal injection of KA into the C5 segment of rat spinal cord induced an excitotoxic lesion. Three days later, experimental animals were treated with an intracerebroventricular injection of human umbilical cord (hUC) MSC whereas control group only received saline solution. Sensory and motor skills as well as neuronal and glial reaction of both groups were recorded. Differences in motor behavior, neuronal counting and glial responses were observed between hUC-MSC-treated and untreated rats. According to the obtained results, we suggest that hUC-MSC therapy delivered into the fourth ventricle using the intracerebroventricular via can exert a neuroprotective or neurorestorative effect on KA-injected animals.Facultad de Ciencias Veterinaria