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

La ruta de señalización WNT en la determinación de progenitores pancreáticos

1 página. IX Jornadas Andaluzas Salud Investiga. Cádiz 20-22 octubre, 2010.Nuestro laboratorio trata de determinar los mecanismos moleculares implicados en la formación de los distintos tipos celulares pancreáticos adultos a partir de células progenitoras. Este conocimiento es fundamental para comprender las bases de enfermedades tan terribles como el cáncer pancreático. Además, es absolutamente necesario para el desarrollo de protocolos de formación in vitro de células beta productoras de insulina, una atractiva estrategia terapéutica para la diabetes. A este respecto, el papel de la ruta de señalización embrionaria Wnt parece ser importante ya que estudios previos han demostrado que la activación de esta ruta es necesaria para la formación de células pancreáticas a partir de células embrionarias. En nuestro proyecto nos hemos planteado determinar el efecto de la ruta Wnt sobre la formación de páncreas sobreactivando dicha ruta en progenitores pancreáticos en el ratón.Peer reviewe

Magnetic localization system for short-range positioning: a ready-to-use design tool

Magnetic localization is used in many indoor positioning applications, such as industrial, medical, and IoT, for its benefits related to the absence of line of sight needs, multipath and fading, the low cost of transmitters and receivers, and the simple development of setups made of coils and magnetic sensors. In short-range applications, this technology could bring some advantages with respect to ultrasound, laser, or RF ones. Nevertheless, fixed both the desired accuracy and the energy constraints, the optimal design of a localization system based on magnetic measurement depends on several factors: the dimension, the number and the optimal positions of the anchors, the uncertainties due to the sensing elements, and the data acquisition systems (DAQs). To preliminary fix all these parameters, suitable simulation environments allow developers to save time and money in developing localization applications. Many magnetic field simulators are available, but it is rare to find those that, considering the uncertainty due to the receiver and DAQs, are able to provide optimal anchors scenario given a target accuracy. To address this problem, this article presents a simulation tool providing the user with design requirements for given target accuracy. The aim of this article is to perform the first steps in providing a ready-to-use specification framework that given the localization domain, the mobile sensors, the DAQ characteristics, and the target accuracy and helps the developer of indoor magnetic positioning systems. The actual validity of the simulation model has been tested on a real setup.Postprint (published version

Intraocular retinal transplants

Embryonic rat retinae transplanted into the anterior chamber of adult rat eyes of the same or different strain survive and grow. Light and electron microscopic studies show that the transplants undergo histogenetic differentiation, resulting in the development of mature inner and outer layer neurons and Muller glial cells. Vascular connections develop between the host iris and the retinal transplant. These initial observations indicate that retinal transplantation to a recipient eye is a procedure which offers ample opportunities for the study of problems related to neural development, retinal plasticity and repair

Molecular mechanisms contributing to TARP regulation of channel conductance and polyamine block of calcium-permeable AMPA receptors.

Many properties of fast synaptic transmission in the brain are influenced by transmembrane AMPAR regulatory proteins (TARPs) that modulate the pharmacology and gating of AMPA-type glutamate receptors (AMPARs). Although much is known about TARP influence on AMPAR pharmacology and kinetics through their modulation of the extracellular ligand-binding domain (LBD), less is known about their regulation of the ion channel region. TARP-induced modifications in AMPAR channel behavior include increased single-channel conductance and weakened block of calcium-permeable AMPARs (CP-AMPARs) by endogenous intracellular polyamines. To investigate how TARPs modify ion flux and channel block, we examined the action of γ-2 (stargazin) on GluA1 and GluA4 CP-AMPARs. First, we compared the permeation of organic cations of different sizes. We found that γ-2 increased the permeability of several cations but not the estimated AMPAR pore size, suggesting that TARP-induced relief of polyamine block does not reflect altered pore diameter. Second, to determine whether residues in the TARP intracellular C-tail regulate polyamine block and channel conductance, we examined various γ-2 C-tail mutants. We identified the membrane proximal region of the C terminus as crucial for full TARP-attenuation of polyamine block, whereas complete deletion of the C-tail markedly enhanced the TARP-induced increase in channel conductance; thus, the TARP C-tail influences ion permeation. Third, we identified a site in the pore-lining region of the AMPAR, close to its Q/R site, that is crucial in determining the TARP-induced changes in single-channel conductance. This conserved residue represents a site of TARP action, independent of the AMPAR LBD

ENTRAP and its potential interaction with European networks

AbstractENTRAP comprises a pan-European cooperation of leading scientific institutions and regulatory bodies in the field of nuclear-waste characterization and its quality assurance for the safe disposal of radioactive waste. Here, the scope of this cooperation is presented and explained and links or interfaces for a potential collaboration with partners fulfilling tasks of IDG-TP are pursued