TRPC1/5-CaV3 Complex Mediates Leptin-Induced Excitability in Hypothalamic Neurons

Leptin regulates hypothalamic POMC+ (pro-opiomelanocortin) neurons by inducing TRPC (Transient Receptor Potential Cation) channel-mediate membrane depolarization. The role of TRPC channels in POMC neuron excitability is clearly established; however, it remains unknown whether their activity alone is sufficient to trigger excitability. Here we show that the right-shift voltage induced by the leptin-induced TRPC channel-mediated depolarization of the resting membrane potential brings T-type channels into the active window current range, resulting in an increase of the steady state T-type calcium current from 40 to 70% resulting in increased intrinsic excitability of POMC neurons. We assessed the role and timing of T-type channels on excitability and leptin-induced depolarization in vitro in cultured mouse POMC neurons. The involvement of TRPC channels in the leptin-induced excitability of POMC neurons was corroborated by using the TRPC channel inhibitor 2APB, which precluded the effect of leptin. We demonstrate T-type currents are indispensable for both processes, as treatment with NNC-55-0396 prevented the membrane depolarization and rheobase changes induced by leptin. Furthermore, co-immunoprecipitation experiments suggest that TRPC1/5 channels and CaV3.1 and CaV3.2 channels co-exist in complex. The functional relevance of this complex was corroborated using intracellular Ca2+ chelators; intracellular BAPTA (but not EGTA) application was sufficient to preclude POMC neuron excitability. However, leptin-induced depolarization still occurred in the presence of either BAPTA or EGTA suggesting that the calcium entry necessary to self-activate the TRPC1/5 complex is not blocked by the presence of BAPTA in hypothalamic neurons. Our study establishes T-type channels as integral part of the signaling cascade induced by leptin, modulating POMC neuron excitability. Leptin activation of TRPC channels existing in a macromolecular complex with T-type channels recruits the latter by locally induced membrane depolarization, further depolarizing POMC neurons, triggering action potentials and excitability.Fil: Perissinotti, Paula Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Martínez Hernández, Elizabeth. Loyola University Of Chicago; Estados UnidosFil: Piedras Rentería, Erika S.. Loyola University Of Chicago; Estados Unido

Narraciones andinas coloniales. Oralidad y visualidad en los Andes

Durante el período colonial (siglos xvi-xviii), continuaron circulando diversos textos, tanto visuales como orales, producidos o registrados por los pobladores andinos. Entre ellos destacan los queros o vasos de madera usados para beber chicha en contextos rituales y de reciprocidad, y los fragmentos de textos orales recogidos en obras como la de Huarochirí o aquellas de Guaman Poma de Ayala y Pachacuti Yamqui. En este trabajo se propone que existía una estrecha relación semiótica entre, por una parte, las narraciones orales y escritas y, por otra parte, aquellas que se pueden identificar en las escenas que decoraban los queros coloniales. La propuesta permite avanzar en el proceso de comprensión respecto del funcionamiento de los lenguajes visuales y orales andinos de aquel tiempo, ampliando el corpus de fuentes que pueden ser usadas para lograr un mejor conocimiento de las voces andinas de ese período.Pendant la période coloniale (xvie-xviiie siècles), quelques textes aussi bien graphiques qu’oraux émanant des populations andines ont continué à circuler. C’est particulièrement le cas des queros, gobelets en bois utilisés pour boire de la chicha lors des rituels de réciprocité, et des fragments de textes oraux recueillis dans des ouvrages tels que le récit de Huarochirí ou les chroniques de Guaman Poma de Ayala et Pachacuti Yamqui. On propose ici l’existence d’une étroite liaison sémiotique entre, d’une part, les textes oraux et écrits et, d’autre part, ce qui peut être identifié dans les scènes peintes sur les queros coloniaux. Tout en amplifiant le corpus de sources mobilisables sur cette époque, on parvient ainsi à une meilleure compréhension du fonctionnement des langages andins de la période coloniale.During the colonial period (16th-18th centuries), various visual and oral texts, produced or registered by Andean people, continued to circulate. Among them, stand out the queros or wooden cups used for drinking chicha in ritual contexts of reciprocity, and the fragments of oral texts collected in works like that of Huarochirí or those of Guaman Poma de Ayala and Pachacuti Yamqui. This paper argues that there was a close connection between the semiotics of oral and written narratives and those that can be identified in the scenes that decorated the colonial queros. This provides a better understanding of the visual and oral Andean language of that period, expanding the corpus of sources that can be used to achieve a better knowledge of the Andean voices of that period

Thermodynamic modeling of sulfate-resistant cements with addition of barium compounds

Comunicación presentada en el International Congress Science and Technology for the Conservation of Cultural Heritage (TechnoHeritage), celebrado en Santiago de compostela del 2 al 5 de octubre de 2012.Sulfate attack by ground waters, soils, etc. is one of the threats to the built heritage in concrete. This study validated through thermodynamic modeling with GEMS geochemical code a new sulfate-resistant formulation based on the addition of BaCO3 and BaO to ordinary Portland cement (OPC), which could be used to replace weathered concrete. The thermodynamic calculations pointed out that Ba ions were able to form an insoluble salt, barite (BaSO4) with the dissolved sulfate which inhibited the formation of ettringite, the latter oc- curred when the concentrations of BaCO3 and BaO were ≥ 6 and ≥ 4 wt.%, respectively. The results of a simulated sulfate a ttack revealed that ettringite precipitated upon ingression of ≥46 ml of a Na2SO4 solution (44 wt.%) in OPC blends with 20 wt.% of BaCO3; whereas with 20 wt.% of BaO, the sulfate that precipitated besides ba rite was monosulfoaluminate when sulfate solution was ≥40 ml (tested up to 52 ml).Funding from the Spanish Ministry of Education and Science (Project CONSOLIDER CSD2007-00058) and the Regional Government of Madrid (Geomaterials Programme) is gratefully acknowledged.Peer Reviewe

Influence of relative humidity on the carbonation of calcium hydroxide nanoparticles and the formation of calcium carbonate polymorphs

A consolidating product based on nanoparticles of slaked lime (Ca(OH)2) dispersed in isopropyl alcohol was exposed under different relative humidities (RH), 33%, 54%, 75% and 90% during 7, 14, 21 and 28days. The characterization of the calcium hydroxide nanoparticles and the formed calcium carbonate polymorphs have been performed by Micro Raman spectroscopy, Transmission Electron Microscopy (TEM), Environmental Scanning Electron Microscopy (ESEM) with Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Diffraction (XRD). Precipitation and transformation of calcium carbonate polymorphs strongly depend on the relative humidity (RH). Higher RH (75%-90% RH) gives rise to amorphous calcium carbonate and monohydrocalcite, calcite, aragonite and vaterite, faster carbonation and larger particles sizes with higher crystallinity compared to lower RH (33%-54% RH) that gives rise mainly to portlandite and vaterite, slower carbonation and smaller particle sizes with lower crystallinity. © 2010 Elsevier B.V.This study was funded by the Government of the Community of Madrid by GEOMATERIALES (S2009/MAT-1629) and CONSOLIDERTCP (CSD2007-0058) and to the JAE-Doc CSIC contracts for supporting P. López-Arce and L.S. Gómez-Villalba to develop this work.Peer Reviewe

In vitro assessment of the role of p53 on chemotherapy treatments in neuroblastoma cell lines

Neuroblastoma is the most frequent malignant extracranial solid tumor of infancy. The overall objective of this work consists of determining the presence of alterations in the p53/MDM2 /p14ARF signaling pathway in neuroblastoma cell lines and deciphering their possible relationship with resistance to known antineoplastic drugs and to differentiation agents. Firstly, we characterized 10 neuroblastoma cell lines for alterations at the p53/MDM2/p14ARF signaling pathway by analysis of TP53 point mutations, MYCN and MDM2 amplification, and p14ARF methylation, homozygous deletions, and expression. Secondly, we chose SK-N-FI (mutated at TP53) and SK-N-Be(2) (wild-type TP53) cell lines, treated them with chemotherapeutic agents (doxorubicin, etoposide, cisplatin, and melphalan) and with two isomers of retinoic acid (RA): (9-cis and all-trans). Finally, we analyzed the distribution of the cell cycle, the induction of apoptosis, and the expression levels of p53, p21, and Bcl-2 in those two cell lines. P14ARF did not present promoter methylation, homozygous deletions, and protein expression in any of the 10 neuroblastoma cell lines. One TP53 point mutation was detected in the SK-N-FI cell line. MYCN amplification was frequent, while most cell lines did not present MDM2 amplification. Treatment of SK-N-FI and SK-N-Be(2) cells with doxorubicin, etopo-side, cisplatin, and melphalan increased apoptosis and blocked the cycle in G2/M, while retinoic acid isomers induced apoptosis and decreased the percentage of cells in S phase in TP53 mutated SK-N-FI cells, but not in TP53 wild-type SK-N-Be(2) cells. Treatment with cisplatin, melphalan, or 9-cis RA decreased p53 expression levels in SK-N-FI cells but not in SK-N-Be (2). The expression of p21 was not modified in either of the two cell lines. Bcl-2 levels were reduced only in SK-N-FI cells after treatment with cisplatin. However, treatments with doxorubicin, etoposide, or 9-cis-RA did not modify the levels of this protein in either of the two cell lines. In conclusion, TP53 mutated SK-N-FI cells respond better to the retinoic isomers than TP53 wild-type SK-N-Be(2) cells. Although these are in vitro results, it seems that deciphering the molecular alterations of the p53/MDM2/p14ARF signaling pathway prior to treating patients of neuroblastoma might be useful for standardizing therapies with the aim of improving survival.This project was funded by a grant from the Fundación Universidad de Navarra, Pamplona, Spain. Idoia Blanco-Luquin received the following fellowship: Beca para la Formación de Tecnólogos del Departamento de Innovación, Empresa y Empleo del Gobierno de Navarra, Pamplona, Spain

Developing new sulfate-resistant cements: a BaCO3 approach

ICCC 2015, Beijing, China, 13~16 October 2015; http://iccc2015.csp.escience.cn/dct/page/1OPC mortar and concretes can be attacked by sulphate solutions giving rise to different decaying processes, related with the formation of ettringite, gypsum, thaumasite etc. At present deterioration due to ettringite formation is avoided by limiting aluminate phase in clinker Portland, however it does not prevent other forms of sulphate attack. Barium carbonate has been used in several fields to eliminate sulphate ion from solutions due to it reacts with them and produces a very insoluble salt, BaSO4. There are in the literature studies demonstrating that ettringite as well as gypsum decompose in the presence of barium carbonate. Studies on the hydration rate of synthetic C3A in the presence of varying percentages of gypsum, BaCO3 or gypsum+BaCO3 revealed that BaCO3 neither regulated the speedy reaction of C3A with water nor reacted with the aluminate. Blends of gypsum plus BaCO3 proved able to regulate C3A hydration. The objective of this paper was to know the behavior of mortars elaborated with optimized mixes of clinker-gypsum-BaCO3 in 4.4 wt% Na2SO4 solution. For this four cements were elaborated by mix of: a) clinker M with 5% of gypsum; b) Clinker M with 3% of gypsum and 15% of BaCO3; c) clinker V and 7 wt% of gypsum; d) clinker V plus 3wt% of gypsum and 15% of BaCO3. Studies on durability were performed on mortar prisms of 10x10x60 mm size, with cement/sand ratio = 1/3 and water/cement ratio = 0.5. Cement Mortar prisms remained submerged under water and under sodium sulfate solution for one year. Samples were extracted from solution after 1,3,5,7 and 12 months and then mechanically tested. XRD and SEM/EDX were performed on the said samples. The compressive but mainly flexural strengths of mortars a), decreased from 5 months in contact with sulphate solution while in the mortars b) strengths remain unaltered after 12 months. Mechanical strengths of mortars c), decreased from 3 months in contact with sulphate solution and were completely destroyed after 12 months of exposition. BaCO3 fails as protector from sulphate attack in d) mortars which were cracked after one year of sulphate exposition. Correlations between mineralogical composition and microstructural changes in mortars along time of test were established.Peer Reviewe

Genetic Deletion of KLHL1 Leads to Hyperexcitability in Hypothalamic POMC Neurons and Lack of Electrical Responses to Leptin

Kelch-like 1 (KLHL1) is a neuronal actin-binding protein that modulates voltage-gated calcium channels. The KLHL1 knockout (KO) model displays altered calcium channel expression in various brain regions. We analyzed the electrical behavior of hypothalamic POMC (proopiomelanocortin) neurons and their response to leptin. Leptin’s effects on POMC neurons include enhanced gene expression, activation of the ERK1/2 pathway and increased electrical excitability. The latter is initiated by activation of the Jak2-PI3K-PLC pathway, which activates TRPC1/5 (Transient Receptor Potential Cation) channels that in turn recruit T-type channel activity resulting in increased excitability. Here we report over-expression of CaV3.1 T-type channels in the hypothalamus of KLHL1 KO mice increased T-type current density and enhanced POMC neuron basal excitability, rendering them electrically unresponsive to leptin. Electrical sensitivity to leptin was restored by partial blockade of T-type channels. The overexpression of hypothalamic T-type channels in POMC neurons may partially contribute to the obese and abnormal feeding phenotypes observed in KLHL1 KO mice.Fil: Perissinotti, Paula Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Martínez Hernández, Elizabeth. Loyola University Of Chicago; Estados UnidosFil: He, Yungui. University of Minnesota; Estados UnidosFil: Koob, Michael D.. University of Minnesota; Estados UnidosFil: Piedras Rentería, Erika S.. Loyola University Of Chicago; Estados Unido

Implementation experience of a patient monitoring solution based on end-to-end standards

Proceeding of: 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBS), Cité Internationale, Lyon, France, August 23-26, 2007.This paper presents a proof-of-concept design of a patient monitoring solution for Intensive Care Unit (ICU). It is end-to-end standards-based, using ISO/IEEE 11073 (X73) in the bedside environment and EN13606 to communicate the information to an Electronic Healthcare Record (EHR) server. At the bedside end a plug-and-play sensor network is implemented, which communicates with a gateway that collects the medical information and sends it to a monitoring server. At this point the server transforms the data frame into an EN13606 extract, to be stored on the EHR server. The presented system has been tested in a laboratory environment to demonstrate the feasibility of this end-to-end standardsbased solution.This research work has been partially supported by projects TSI2005-07068-C02-01 and TSI2004-04940-C02-01 from Ministerio de Educación y Ciencia (Spanish Government), and a personal grant to both M.Galarraga and M. Martínez-Espronceda from Navarre Regional Government