43 research outputs found
S100B alters neuronal survival and dendrite extension via RAGE-mediated NF-κB signaling
No full textS100B is a soluble protein secreted by astrocytes that exerts pro-survival or pro-apoptotic effects depending on the concentration reached in the extracellular millieu. The S100B receptor termed RAGE (for receptor for advanced end glycation products) is highly expressed in the developing brain but is undetectable in normal adult brain. In this study, we show that RAGE expression is induced in cortical neurons of the ischemic penumbra. Increased RAGE expression was also observed in primary cortical neurons exposed to excitotoxic glutamate (EG). S100B exerts effects on survival pathways and neurite extension when the cortical neurons have been previously exposed to EG and these S100B effects were prevented by anti-RAGE blocking antibodies. Furthermore, nuclear factor kappa B (NF-κB) is activated by S100B in a dose- and RAGE-dependent manner and neuronal death induced by NF-κB inhibition was prevented by S100B that restored NF-κB activation levels. Together, these findings suggest that excitotoxic damage can induce RAGE expression in neurons from ischemic penumbra and demonstrate that cortical neurons respond to S100B through engagement of RAGE followed by activation of NF-κB signaling. In addition, basal NF-κB activity in neurons is crucial to modulate the extent of pro-survival or pro-death S100B effects.Fil: Villarreal, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Aviles Reyes, Rolando Xavier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Angelo, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Reines, Analia Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Investigaciones Farmacológicas; ArgentinaFil: Ramos, Alberto Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; Argentin
Expression is induced in isolated neurons of the penumbra after ischemia by cortical devascularization
No full textThe p75 neurotrophin receptor (p75NTR) is involved in neuronal functions going from induction of apoptosis and growth inhibition to the promotion of survival. p75NTR expression is induced in central nervous system (CNS) by a wide range of pathological conditions where it seems to have a main role in neuronal death and axonal growth inhibition. The cellular mechanisms driving p75NTR expression in cell lines and primary neurons in culture depend on Sp1-induced transcription (Ramos et al., 2007, J. Neurosci 27:1498). In this study we analyzed the spatio-temporal profile of p75NTR expression after a localized ischemic lesion in the rat brain induced by cortical devascularization (CD). Our results showed that p75NTR expression occurred in isolated neurons of the ischemic penumbra. The p75NTR+ neurons presented morphological alterations and active caspase-3 staining. Some of these p75NTR+ neurons were also positive for sortilin. The peak of p75NTR expression was localized 3 days after the lesion (3DPL), while abundance of Sp1 transcription factor increased from 3 to 14DPL on the lesioned hemisphere. In primary cortical neurons, we demonstrated that p75NTR expression is induced by excitotoxic stress and correlated with increased Sp1 abundance. We conclude that p75NTR expression is localized in selected neurons of the ischemic penumbra and these neurons are probably condemned to apoptotic cell death. In primary neuronal culture is clear that excitotoxity and Sp1 are involved in induction of p75NTR expression, although in vivo some additional mechanisms are likely to be involved in the control of the p75NTR expression in specific neurons in vivo.Fil: Angelo, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Aviles Reyes, Rolando Xavier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Villarreal, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Barker, Philip A.. McGill University; CanadáFil: Reines, Analia Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Investigaciones Farmacológicas; ArgentinaFil: Ramos, Alberto Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; Argentin
Identificación y caracterización de subtipos de Escherichia coli enteropatógena típica y atípica, aislados de muestras fecales de pacientes menores a 5 años de edad con cuadro diarreico agudo, en la ciudad de Quito, 2013
No full textEscherichia coli Enteropatógena (EPEC) es un patógeno estricto del ser humano y de algunas especies animales; este microorganismo es causante de disenterías a nivel mundial y se encuentra en cualquier reservorio, sea este alimento o agua contaminada. Su contagio es fácil y la cantidad de colonias necesarias para infectar al ser humano es mínima, (107 Unidades Formadoras de Colonia por mililtro). Este patotipo se divide en dos subtipos con características similares pero genotípicamente la ausencia de un segmento genético completo induce la aparición de un subtipo atipico de mayor resistencia a la terapia general. Al ser una bacteria muy común que afecta principalmente a poblaciones suceptibles como niños menores de 5 años de edad se ha evidenciado que representa la cuarta causa de muerte en el Ecuador según los organismos de control (INEN, 2010). Análisis estadísticos de este patotipo lo categorizan con una prevalencia del 51,4% (Datos no publicado) sin embargo en el país no se han realizado este tipo de estudios estadísticos de los subtipos típico y atípico de ECEP. En la presente investigación, se propuso determinar la prevalencia de este microrganismo por medio de la realización de un estudio del tipo observacional, descriptivo y transversal. Para la determinación de los subtipos de Escherichia coli Enteropatógena, se basó en el método de biología molecular denominado Reacción en Cadena de la Polimeraza (PCR convencional), con el cual se logró identificar la presencia o ausencia de los genes “eae” y “bfp”; y por medio del análisis estadístico se obtuvó el respectivo resultado de prevalencia para la población estudiada.
Por otro lado se probó que el microorganismo ECEP atípica es la más prevalente en la población investigada (89,36%); se consigió estandarizar la técnica de reacción en cadena de la polimeraza (PCR convencional); además por medio de un análisis de la densidad óptica relativa de los geles de agarosa después de realizar el revelado, el cual revela un valor numérico del gen amplificad
Identificación y caracterización de subtipos de Escherichia coli enteropatógena típica y atípica, aislados de muestras fecales de pacientes menores a 5 años de edad con cuadro diarreico agudo, en la ciudad de Quito, 2013
No full textEscherichia coli Enteropatógena (EPEC) es un patógeno estricto del ser humano y de algunas especies animales; este microorganismo es causante de disenterías a nivel mundial y se encuentra en cualquier reservorio, sea este alimento o agua contaminada. Su contagio es fácil y la cantidad de colonias necesarias para infectar al ser humano es mínima, (107 Unidades Formadoras de Colonia por mililtro). Este patotipo se divide en dos subtipos con características similares pero genotípicamente la ausencia de un segmento genético completo induce la aparición de un subtipo atipico de mayor resistencia a la terapia general. Al ser una bacteria muy común que afecta principalmente a poblaciones suceptibles como niños menores de 5 años de edad se ha evidenciado que representa la cuarta causa de muerte en el Ecuador según los organismos de control (INEN, 2010). Análisis estadísticos de este patotipo lo categorizan con una prevalencia del 51,4% (Datos no publicado) sin embargo en el país no se han realizado este tipo de estudios estadísticos de los subtipos típico y atípico de ECEP. En la presente investigación, se propuso determinar la prevalencia de este microrganismo por medio de la realización de un estudio del tipo observacional, descriptivo y transversal. Para la determinación de los subtipos de Escherichia coli Enteropatógena, se basó en el método de biología molecular denominado Reacción en Cadena de la Polimeraza (PCR convencional), con el cual se logró identificar la presencia o ausencia de los genes “eae” y “bfp”; y por medio del análisis estadístico se obtuvó el respectivo resultado de prevalencia para la población estudiada.
Por otro lado se probó que el microorganismo ECEP atípica es la más prevalente en la población investigada (89,36%); se consigió estandarizar la técnica de reacción en cadena de la polimeraza (PCR convencional); además por medio de un análisis de la densidad óptica relativa de los geles de agarosa después de realizar el revelado, el cual revela un valor numérico del gen amplificad
Intermittent hypoxia during sleep induces reactive gliosis and limited neuronal death in rats: Implications for sleep apnea
No full textSleep apnea (SA) can be effectively managed in humans but it is recognized that when left untreated, SA causes long-lasting changes in neuronal circuitry in the brain. Recent neuroimaging studies gave suggested that these neuronal changes are also present even in patients successfully treated for the acute effects of SA. The cellular mechanisms that account for these changes are not certain but animal models of intermittent hypoxia (IH) during sleep have shown neuronal death and impairment in learning and memory. Reactive gliosis has a drastic effect on neuronal survival and circuitry and in this study we examined the neuro-glial response in brain areas affected by SA. Glial and neuronal alterations were analyzed after 1, 3, 5 and 10 days of exposure to IH (8 h/day during the sleep phase, cycles of 6 min each, 10-21% O2) and observed significant astroglial hyperplasia and hypertrophy in parietal brain cortex and hippocampus by studying gliofibrillary acidic protein, Vimentin, S100B and proliferating cell nuclear antigen expression. In addition, altered morphology, reduced dendrite branching and caspase activation were observed in the CA-1 hippocampal and cortical (layers IV-V) pyramidal neurons at short exposure times (1-3 days). Surprisingly, longer exposure to IH reduced the neuronal death rate and increased neuronal branching in the presence of persistent reactive gliosis. Up-regulation of hypoxia inducible factor 1 alpha (HIF-1α) and mdr-1, a HIF-1α target gene, were observed and increased expression of receptor for advanced end glycated products and its binding partner S100B were also noted. Our results show that a low number of hypoxic cycles induce reactive gliosis and neuronal death whereas continuous exposure to IH cycles reduced the rate of neuronal death and induced neuronal branching on surviving neurons. We hypothesize that HIF-1α and S100B glial factor may improve neuronal survival under hypoxic conditions and propose that the death/survival/re-growth process observed here may underlie brain circuitry changes in humans with SA.Fil: Aviles Reyes, Rolando Xavier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Angelo, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Villarreal, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Rios, Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Lazarowski, Alberto Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Ramos, Alberto Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; Argentin
P1‐178: ASTROCYTIC OVEREXPRESSION OF NRF2 LEADS TO REDUCED DISEASE PROGRESSION IN APP/PS1 TRANSGENIC MICE
No full textHugo Brehme. Los prototipos mexicanistas. Num. 16 Año 6 (2002-2003) invierno. Alquimia. Sistema Nacional de Fototecas
No full text- Hugp Brehme o la construcción nacional - Hugo Brehme: un gigante de la fotografía mexicana, por Dennis Brehme - Hugo Brehme y Sergei Eisenstein: una convergencia, por Aurelio de los Reyes - El imagunario de Hugo Brehme / Arno Brehme, un acto olvidado - La exportación de lo mexicano: Hugo Brehme en casa y en el extranjero, por Jesse Lerner - El artista fotógrafo Hugo Brehme / Nada se salvó en la conocida casa artísitica - La colección Hugo Brehme, por Mayra Mendoza Avilés - El horizonte técnico en Hugo Brehme, por Heladio Vera Trejo
Publication of works presented in the 2016 and 2018 editions of the National Student Scientific Event on Internal Medicine -MEDINTÁVILA
No full textAnalytical cross-sectional study. The research works presented in the 2nd and 3rd editions of Medintávila, held from November 16 to 19, 2016, and April 4 to 8, 2018, respectively, were analyzed. Of the 422 papers presented (255 in 2016 and 167 in 2018), 87 were excluded because they did not include all the variables to be evaluated, so the final sample was 335 papers.
Variables and search methods were defined as outlined in the study by Corrales-Reyes et al. The variable of interest studied was "publication," which was characterized as the publication in a scientific journal of the work presented at the event; the study was conducted two years after the latest edition of Medintávila (2018), a time lapse considered adequate for obtaining a speedy post-publication citation. A published work was defined in this context as one in which there was a correspondence between the work presented at the event and the article published in terms of topic, place of study, main results, and at least one author. The works contained in the abstract books of the Universidad Médica Pinareña student journal were not considered as publications because they only included title, authors, affiliations, abstract, and key words.
The research works presented at the event were made available in extenso by the GCE of the UCMCAV; they were reviewed between April 2019 and March 2020 to collect the information on the variables to be analyzed and enter it into a Microsoft Excel database. The study variables were: title; university where the authors studied; thematic areas (predetermined by the organizers of the event in each call); language of presentation (Spanish and English); edition of the event (2016 or 2018); type; number of authors; academic year and degree of the first author (medicine, oral medicine, nursing, and health technology degrees); participation of tutors/advisors (yes or no); awards (no award, relevant award, outstanding award, and mention award); number of references, and obsolescence (Price index).
Each work was classified into one of the following thematic areas: primary health care; chronic diseases; infectious diseases; herbal and traditional medicine; children and women; elderly; medical education; emergencies; and interdisciplinarity. Furthermore, according to their type, works were classified into free topics, finished research works, literature reviews, and case reports. The Price index was computed by dividing the number of references ≤5 years old (relative to the date of the event) by the total number of references cited in each paper.
The works classified as free topics and finished research works (both with a structure including Introduction, Materials and Methods, Results, and Discussion, or their equivalents) (n=208) were also grouped according to their methodological characteristics into: a) design: case series/report, cross-sectional, cases and controls, cohorts, experimental, and others; b) intervention: observational, experimental, or quasi-experimental; c) objective according to data analysis: descriptive or analytical; d) temporality (defined by the time data was collected): retrospective, prospective, or ambispective; e) patient follow-up: cross-sectional or longitudinal study; and e) multicenter study (defined as one that was carried out under the same methodology using data from at least two research centers or care units): yes or no.
To determine whether the papers were published in scientific journals, a search strategy was developed, in Spanish and English, consisting of a combination of terms that included the subject and place, as well as the name of the first, second and last authors of the study, as shown below: («Tema de estudio» AND «lugar de estudio») AND (autor: primero OR autor: segundo OR autor: último) and («Study topic» AND «study place») AND (author: first OR author: second OR author: last). The search, which was developed in April 2020, was performed in Google Scholar since this search engine has the capacity to locate articles and citations in journals indexed in the most important databases and, because of its low power of exclusion, it accepts most publications, even those that do not appear in the most widely used databases.
Articles classified as published were evaluated for the following characteristics: (A) title (to determine if there were changes); (b) journals with their corresponding country of publication and indexing (SciELO, Web of Science, PubMed/MEDLINE, and Scopus); (c) year of publication; d) number of citations according to Google Scholar (search performed on September 8, 2020); e) authors (to determine if there were changes: addition, exclusion, order, and mixed); and f) language of publication.
Data analysis was performed using descriptive statistics: absolute and relative frequencies were used for categorical variables, while means and standard or median deviations and interquartile ranges were calculated for numerical variables, according to the assumptions of normality determined through the Shapiro-Wilk test. Bivariate analyzes were performed to determine whether there were characteristics of the papers associated with their publication in scientific journals, calculating crude prevalence ratios (cPR), adjusted prevalence ratios (aPR), and their corresponding 95% confidence intervals (95%CI); p -values were also calculated using generalized linear models (Poisson regression, log link function) in which each university presenting the research was used as a cluster. Statistical analysis was carried out using the Stata v.11.1 software and a significance level of p<0.05 was considered.
The study followed the recommendations for conducting research with secondary data and preserved the confidentiality of the information obtained. As this is a research done using publicly available data, no approval by an ethics committee was required
Operative mine planning, design and geological modeling: Integration based on topological representations
No full textDoctor en Ingeniería de MinasScientific and engineering efforts in mine planning theory are focused on improving the speed and size capacity of existing algorithms. They look for changing from minutes to seconds, and hundreds of thousands to million blocks of an ore body representation. However, mining practices are so full of manual work and personal decisions, that algorithmic solutions are changed considerably by the mine planner, lasting weeks in this process to achieve operative final results.
This thesis proposes a different point of view, joining some of such hand work decisions, like design and ore body modeling.
The developed work concentrates on parametric representations of mine design and an ore body model, through volumes and morphological tools, optimized by simulated annealing. It is shown that it is possible to model and optimize a final open pit, with road, benches and switch-backs design and to fit an ore body with parametric volumes, which include geological knowledge.
The principal applications of such results are: mine design could be obtained in minutes instead of weeks, the project value will not change because of handmade decisions, mine operation and geological units will have a common language through parametric volumes, geostatistical predictions will depend on geological knowledge and fitted data, geological uncertainty would be modeled from parameter stochasticity, so stochastic optimization could be implemented from simulations. In fact, mine planning algorithm inputs would no longer be a block model, but directly drill hole data.
Despite that some numeral examples were developed, real cases were not the scope of this thesis work. The value of this work concentrates on proposing ideas and a new field of investigation in mine planning, focused on more realistic mining needs and bringing different tools, as those that until today were the paradigm, and trying to join professional areas that work separately
Análisis del Comportamiento del crédito hipotecario entre la banca privada y la banca pública 2007-2015.
No full textEl trabajo está enfocado en realizar una investigación alusiva al sector crediticio hipotecario del Ecuador en
los ámbitos de la banca pública y privada, abordando la temática durante el periodo comprendido entre el
año 2007 al año 2015, el estudio hace una descripción esquemática del Sistema Financiero Ecuatoriano, su
vínculo con el desarrollo económico, las condiciones y características generales de las políticas crediticias
en el área de los créditos hipotecarios, un análisis estadístico de la banca pública y privada, haciendo énfasis
en el análisis y las relaciones de las entidades crediticias tanto públicas como privadas y su participación en
el Sistema Financiero Ecuatoriano, describiendo y comparando las políticas crediticias, los montos
concedidos por concepto de créditos hipotecarios a lo largo del periodo del estudio, e identificando cuales
son los actores principales en la concesión de créditos hipotecarios en el país
