Successful Xenografts of Second Trimester Human Fetal Brain and Retinal Tissue in the Anterior Chamber of the Eye of Adult Immunosuppressed Rats

Successful xenografting of first trimester human fetal CNS tissue and retina has been reported in the literature. We wished to test the feasibility ofusing the anterior chamber ofthe rat eye to support the development of more mature human fetal xenografts. Here we report on the successful outcome of human brain and retinal transplants. Adult host rats immunosuppressed with cyclosporin A accepted these xenografts and supported their further development. Periodic examination of the host eyes using a direct ophthalmoscope or an ophthalmic slit lamp permitted direct visual monitoring of the health and growth of the transplants. Histologically it was possible to identify neuronal, macroglial, and microglial (macrophage) cell types within the grafts. Mitotic activity and histogenetic differentiation took place. Blood vessels filled with hematic cells were commonly present within the grafts. The walls of these vessels prevented the leakageofhorseradish peroxidase, suggesting the presence of a functional brain-blood barrier in the graft. These results indicate that it is possible to use a small animal model to study normal and pathological phenomena oniate fetal human neural tissues. Our group has already taken advantage of the model to achieve HIV infectivity offetal human brain outside the human body

Intraretinal Transplantation for Rod-Cell Replacement in Light-Damaged Retinas

Blindness from retinal disease is often the consequence of extensive damage to the photoreceptor cell population, while other cell types which form the neural retina are relatively spared. In this setting, transplantation of photoreceptor cells could offer hope for the restoration of some degree of visual function. We testd the feasibility of this approach by transplanting immature retinal cells into the eyes of adult rats affected by late stage phototoxic retinopathy, which are almost totally devoid of photoreceptor cells

Analogías de redes eléctricas como herramienta educativa para el estudio de diversos fenómenos físicos

La resolución de problemas correspondientes a fenómenos físicos regidos por ecuaciones diferenciales en derivadas parciales, lineales o no, implica un conocimiento profundo de cálculo analítico o numérico por lo que, en general, estos problemas no se encuentran al alcance de los alumnos de facultades de ciencias o escuelas de ingeniería, desconocedores en su fase de formación de estas modernas y complejas técnicas matemáticas.A pesar de ello, es posible, en muchos casos, abordar la resolución de los mismos recurriendo al empleo de analogías y resolviendo los modelos formalmente equivalentes (es decir, regidos por el mismo conjunto de ecuaciones) mediante programas de ordenador adecuados a tal fin. Este es el caso de las analogías eléctricas ya que, una vez elaborado el modelo en red, se dispone de programas de resolución de circuitos de fácil manejo

Phase coexistence in highly deuterated ferroelectric triglycine selenate: Landau description

The phase transition in a 90% deuterated sample of TGSe has been investigated by calorimetric and dielectric measurements. As a consequence of the presence of an internal crack in the sample, the transition takes place in two stages separated by an interval where the paraelectric and the ferroelectric phases coexist without latent heat contribution. From the latent heat, the specific heat excess and the Curie law for the dielectric constant, it is shown that the transition follows a 2-4-6 Landau potential, whose coefficients are determined. This potential describes completely all the data, including those corresponding to the coexistence interval.Dirección General de Investigación Científica y Técnica (DGICYT) FIS2005-0244

Stem cells as a therapeutic tool for the blind: biology and future prospects

Retinal degeneration due to genetic, diabetic and age-related disease is the most common cause of blindness in the developed world. Blindness occurs through the loss of the light-sensing photoreceptors; to restore vision, it would be necessary to introduce alternative photosensitive components into the eye. The recent development of an electronic prosthesis placed beneath the severely diseased retina has shown that subretinal stimulation may restore some visual function in blind patients. This proves that residual retinal circuits can be reawakened after photoreceptor loss and defines a goal for stem-cell-based therapy to replace photoreceptors. Advances in reprogramming adult cells have shown how it may be possible to generate autologous stem cells for transplantation without the need for an embryo donor. The recent success in culturing a whole optic cup in vitro has shown how large numbers of photoreceptors might be generated from embryonic stem cells. Taken together, these threads of discovery provide the basis for optimism for the development of a stem-cell-based strategy for the treatment of retinal blindness

Procedimiento metodológico para implicar a los profesionales de especialidades técnicas y carreras universitarias en la evaluación del proceso de formación de sus habilidades profesionales asumiendo un enfoque de competencias

The work shows a methodological procedure that allows to imply the professionals in process of formation of technical specialties and university careers in the evaluation of the process of formation of its professional abilities assuming for it a focus of competitions. For he/she intends a system of indicators with their corresponding scales of valuation that allow to end up dominating the level that the students reach in the formation of the same ones; as well as, the regulation of the one referred process with effectiveness, without ignoring the affective of the personality and the educational of the process.El trabajo muestra un procedimiento metodológico que permite implicar a los profesionales en proceso de formación de especialidades técnicas y carreras universitarias, en la evaluación del proceso de formación de sus habilidades profesionales, asumiendo para ello un enfoque de competencias. Para tal efecto, se propone un sistema de indicadores con sus correspondientes escalas de valoración, que permite llegar a dominar el nivel que los estudiantes alcanzan en la formación de las mismas, así como la regulación del referido proceso con efectividad, sin ignorar lo afectivo de la personalidad y lo educativo del proceso

Los bosquetes de los khaloa (morabitos) del Rif, Atlas Medio y región del Sus de Marruecos

La franja del norte de África está salpicada de pequeños santuarios en los que se encuentran los restos de hombres de clara significación en la historia local o regional. Estos lugares se distinguen bien en el territorio por la cubierta vegetal que suele acompañarlos, fruto del espíritu devoto de respeto que tienen hacia ellos los habitantes de la zona. El origen de los mismos se encuentra en los altares del politeísmo preislámico y precristiano. En diversas campañas se ha muestreado un pequeño grupo de estos khaloas (marabuts o morabitos) en las principales cadenas montañosas de Marruecos, tomando en consideración ciertos parámetros ambientales y biológicos. El clima parece ser el principal responsable de la entidad de la cubierta vegetal que rodea las construcciones. El Rif es la zona marroquí que mantiene las mejores masas arbóreas de los morabitos, pudiéndose hallar árboles de una envergadura impresionante. Se ha profundizado en el estudio en una caracterización de un grupo de 24 marabuts de la región Jbala del Rif occidental, su riqueza florística y de sus dimensiones espaciales, en un intento de definir una tipología de los mismos. La realidad de hoy no puede asegurar la persistencia de estas islas del paisaje porque las corrientes de los grupos más extremistas no toleran a los intermediarios en la liturgia.The strip of North Africa is sprinkled of small sanctuaries in which are the rests of men of clear meaning in local or regional history. These places are clearly distinguished by the vegetal cover that usually accompanies them, fruit of the devotee spirit of respect shown by local inhabitants. The origin of these khaloas is in the altars of preIslamic and preChristian politeism. In several field campaigns, a small group of khaloas has been sampled in the main mountainous chains of Morocco, taking into consideration certain environmental and biological parameters. Climate seems to be the main factor controlling the composition and structure of the vegetal cover surrounding these constructions. The Rif is the Moroccan zone maintaining the best arboreal masses in khaloas, which commonly shelter monumental trees. We have carried out a detailed study of 24 khaloas in the Region of Jbala (western Rif), in an attempt to define khaloas tipologies based on floristic richness and structure. Current socio-cultural conditions cannot assure the persistence of these islands in the landscape because most extremist groups do not tolerate intermediaries in their liturgy.Trabajo realizado mediante un proyecto conjunto de colaboración financiado por la Agencia Española de Cooperación Internacional (AECI-PCI Hispano-Marroquí). Proyecto nº 19/03/P

Memory effect in triglycine sulfate induced by a transverse electric field: specific heat measurement

The influence of a transverse electric field on the specific heat of triglycine sulfate (TGS) has been studied. The specific heat of TGS has been measured on heating the sample from the ferroelectric to the paraelectric phase after prolonged application of transverse electric field (i.e. perpendicular to the ferroelectric axis). It is shown that the specific heat of TGS can 'remember' the temperature T(s) at which the transverse field was previously applied.España, Gobierno de España IS-2006-0404