Fundación Instituto Leloir

About: Fundación Instituto Leloir is a facility organization based out in Buenos Aires, Argentina. It is known for research contribution in the topics: Dentate gyrus & Neurogenesis. The organization has 702 authors who have published 1052 publications receiving 39299 citations.

High viscosity xanthan polymer preparations

Abstract: Increasing the molecular length of xanthan polymer makes a higher viscosity xanthan composition. Xanthan with higher specific viscosity characteristics provides more viscosity at equivalent concentration in food, industrial and oilfield applications. Methods for increasing the viscosity of xanthan include inducing particular key genes and increasing copy number of particular key genes.

Different efficacy of in vivo herpes simplex virus thymidine kinase gene transduction and ganciclovir treatment on the inhibition of tumor growth of murine and human melanoma cells and rat glioblastoma cells.

Abstract: Initial studies have demonstrated the therapeutic efficacy for cancer treatment of in vivo transfer of the herpes simplex virus thymidine kinase gene followed by ganciclovir (GCV) treatment. However, recent studies have questioned the validity of this approach. Using retroviral vector-producing cells (VPC) as a source for in vivo gene transfer, we evaluated the efficacy of in vivo transduction of malignant cells using three different tumor cell models: B16 murine and IIB-MEL-LES human melanomas and a C6 rat glioblastoma. In vitro studies showed a bystander effect only in C6 cells. In vivo studies showed an inhibition of tumor growth in the two melanoma models when tumor cells were coinjected with VPC-producing retroviral vectors carrying the herpes simplex virus thymidine kinase gene, followed by GCV treatment; however, 100% of mice developed tumors in both models. Under similar experimental conditions, 70% (7 of 10) of syngeneic rats completely rejected stereotactically transferred C6 tumor cells; most of them (5 of 10) showed a prolonged survival. Treating established C6 tumors with VPC-producing retroviral vectors carrying the herpes simplex virus thymidine kinase gene and GCV led to the cure of 33% (4 of 12) of the animals. Rats that rejected tumor growth developed an antitumor immune memory, leading to a rejection of a stereotactic contralateral challenge with parental cells. The immune infiltrate, which showed the presence of T lymphocytes, macrophages, and polymorphonuclear cells at the site of the first injection and mainly T lymphocytes and macrophages at the site of tumor challenge, strengthened the importance of the immune system in achieving complete tumor rejection.

Bursting Neurons in the Hippocampal Formation Encode Features of LFP Rhythms.

Abstract: Burst spike patterns are common in regions of the hippocampal formation such as the subiculum and medial entorhinal cortex (MEC). Neurons in these areas are immersed in extracellular electrical potential fluctuations often recorded as the local field potential (LFP). LFP rhythms within different frequency bands are linked to different behavioral states. For example, delta rhythms are often associated with slow-wave sleep, inactivity and anesthesia; whereas theta rhythms are prominent during awake exploratory behavior and REM sleep. Recent evidence suggests that bursting neurons in the hippocampal formation can encode LFP features. We explored this hypothesis using a two-compartment model of a bursting pyramidal neuron driven by time-varying input signals containing spectral peaks at either delta or theta rhythms. The model predicted a neural code in which bursts represented the instantaneous value, phase, slope and amplitude of the driving signal both in their timing and size (spike number). To verify whether this code is employed in vivo, we examined electrophysiological recordings from the subiculum of anesthetized rats and the MEC of a behaving rat containing prevalent delta or theta rhythms, respectively. In both areas, we found bursting cells that encoded information about the instantaneous voltage, phase, slope and/or amplitude of the dominant LFP rhythm with essentially the same neural code as the simulated neurons. A fraction of the cells encoded part of the information in burst size, in agreement with model predictions. These results provide in-vivo evidence that the output of bursting neurons in the mammalian brain is tuned to features of the LFP.