University of Costa Rica

About: University of Costa Rica is a education organization based out in San José, Costa Rica. It is known for research contribution in the topics: Population & Venom. The organization has 9817 authors who have published 16781 publications receiving 238208 citations. The organization is also known as: UCR & Universidad de Costa Rica.

GABAergic modulation with classical benzodiazepines prevent stress-induced neuro-immune dysregulation and behavioral alterations.

Abstract: Objective Psychosocial stress is associated with altered immunity, anxiety, and depression. Repeated social defeat (RSD), a model of social stress, triggers egress of inflammatory myeloid progenitor cells (MPCs; CD11b+/Ly6Chi) that traffic to the brain, promoting anxiety-like behavior. In parallel, RSD enhances neuroinflammatory signaling and long-lasting social avoidant behavior. Lorazepam and clonazepam are routinely prescribed anxiolytics that act by enhancing GABAergic activity in the brain. Besides binding to the central benzodiazepine binding site (CBBS) in the central nervous system (CNS), lorazepam binds to the translocator protein (TSPO) with high affinity causing immunomodulation. Clonazepam targets the CBBS and has low affinity for the TSPO. Here the aims were to determine if lorazepam and clonazepam would: (1) prevent stress-induced peripheral and central inflammatory responses, and (2) block anxiety and social avoidance behavior in mice subjected to RSD. Methods C57/BL6 mice were divided into experimental groups, and treated with either lorazepam (0.10 mg/kg), clonazepam (0.25 mg/kg) or vehicle (0.9% NaCl). Behavioral data and tissues were collected the morning after the last cycle of RSD. Results Lorazepam and clonazepam were effective in attenuating mRNA expression of CRH in the hypothalamus and corticosterone in plasma in mice subjected to RSD. Both drugs blocked stress-induced levels of IL-6 in plasma. Lorazepam and clonazepam had different effects on stress-induced enhancement of myelopoiesis and inhibited trafficking of monocytes and granulocytes in circulation. Furthermore, lorazepam, but not clonazepam, inhibited splenomegaly and the production of pro-inflammatory cytokines in the spleen following RSD. Additionally, lorazepam and clonazepam, blocked stress-induced accumulation of macrophages (CD11b+/CD45high) in the CNS. In a similar manner, both lorazepam and clonazepam prevented neuroinflammatory signaling and reversed anxiety-like and depressive-like behavior in mice exposed to RSD. Conclusion These data support the notion that lorazepam and clonazepam, aside from exerting anxiolytic and antidepressant effects, may have therapeutic potential as neuroimmunomodulators during psychosocial stress. The reversal of RSD-induced behavioral outcomes may be due to the enhancement of GABAergic neurotransmission, or some other off-target effect. The peripheral actions of lorazepam, but not clonazepam, seem to be mediated by TSPO activation.

Tsunami hazard in the Caribbean: Regional exposure derived from credible worst case scenarios

Abstract: The present study documents a high tsunami hazard in the Caribbean region, with several thousands of lives lost in tsunamis and associated earthquakes since the XIXth century Since then, the coastal population of the Caribbean and the Central West Atlantic region has grown significantly and is still growing Understanding this hazard is therefore essential for the development of efficient mitigation measures To this end, we report a regional tsunami exposure assessment based on potential and credible seismic and non-seismic tsunamigenic sources Regional tsunami databases have been compiled and reviewed, and on this basis five main scenarios have been selected to estimate the exposure The scenarios comprise two Mw8 earthquake tsunamis (north of Hispaniola and east of Lesser Antilles), two subaerial/submarine volcano flank collapse tsunamis (Montserrat and Saint Lucia), and one tsunami resulting from a landslide on the flanks of the Kick'em Jenny submarine volcano (north of Grenada) Offshore tsunami water surface elevations as well as maximum water level distributions along the shore lines are computed and discussed for each of the scenarios The number of exposed people has been estimated in each case, together with a summary of the tsunami exposure for the earthquake and the landslide tsunami scenarios For the earthquake scenarios, the highest tsunami exposure relative to the population is found for Guadeloupe (65%) and Antigua (75%), while Saint Lucia (45%) and Antigua (5%) have been found to have the highest tsunami exposure relative to the population for the landslide scenarios Such high exposure levels clearly warrant more attention on dedicated mitigation measures in the Caribbean region

Las redes sociales: una nueva herramienta de difusión

Abstract: Las redes sociales han marcado un hito en materia de difusion masiva, debido a su alcance, caracteristicas e impacto en la sociedad actual. Son utilizadas tanto por individuos como por empresas, dado que permiten lograr una comunicacion interactiva y dinamica. Durante los ultimos anos, han surgido muchos tipos de redes sociales, tanto en el ambito social o general, como en el corporativo, para efectos de negocios, o bien en temas especificos de interes de grupos o segmentos determinados. Sin embargo, el objetivo comun se cumple en el tanto se logra una comunicacion fluida y eficaz con grupos especificos de interes, incluyendo esto desde la posibilidad de atender la necesidad de pertenencia social hasta facilitar la proyeccion y posicionamiento de empresas, bienes, servicios, o incluso para ser utilizadas en campanas politicas. Asimismo, y aunque durante los ultimos anos, segun Celaya (2008), su crecimiento ha tendido a disminuir para dar espacio a nuevas plataformas mas especializadas en areas tematicas, las redes sociales seguiran siendo uno de los medios de comunicacion masiva mas importantes, debido a sus caracteristicas y a las opciones que ofrecen a sus usuarios.

Characterization of aspercetin, a platelet aggregating component from the venom of the snake Bothrops asper which induces thrombocytopenia and potentiates metalloproteinase-induced hemorrhage.

Abstract: Thrombocytopenia occurs in a number of patients bitten by Bothrops asper, a species responsible for the majority of snakebites in Central America and southern Mexico. In this work we describe the isolation of a new platelet-aggregating protein, named aspercetin, from the venom of B. asper, which induces thrombocytopenia in mice. Isolation was carried out by a combination of ion-exchange chromatography on DEAE-Sepharose and affinity chromatography on Affi-Gel Blue. Aspercetin is a disulfide-linked heterodimer, with a pI of 4.5 and a molecular mass of 29,759 Da, detemined by MALDI-ESI mass spectrometry. N-terminal sequence shows homology with a number of venom proteins which belong to the C-type lectin family. Aspercetin has functional similarities with botrocetin, from B. jararaca venom, since it induces platelet aggregation only in the presence of plasma or purified von Willebrand factor. Aspercetin-mediated platelet aggregation results from the interaction of von Willebrand factor with platelet receptor GPIb. Aspercetin lacks anticoagulant effect and does not agglutinate erythrocytes, in contrast with other representatives of the C-type lectin family isolated from snake venoms. Moreover, aspercetin is not lethal, nor does it induce myonecrosis, hemorrhage and edema. When injected intravenously or intramuscularly in mice it induces a rapid, dose-dependent drop in platelet counts and prolongs the bleeding time, suggesting that it may play a role in the thrombocytopenia that develops in a number of B. asper envenomations. Moreover, mice injected intravenously with aspercetin and then receiving an intradermal injection of B. asper hemorrhagic metalloproteinase BaP1 develop a larger hemorrhagic lesion than mice receiving only BaP1. This suggests that aspercetin, by reducing platelet numbers, may contribute to the hemorrhagic effect characteristic of B. asper envenomations.