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Search Results: 1 - 10 of 14089 matches for " Gabriel Gutiérrez-Ospinac "
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Selective and constructive mechanisms contribute to neural circuit formation in the barrel cortex of the developing rat  [PDF]
Eileen Uribe-Querol, Eduardo Martínez-Martínez, Luis Rodrigo Hernández, Patricia Padilla Cortés, Horacio Merchant-Larios, Gabriel Gutiérrez-Ospinac
Advances in Bioscience and Biotechnology (ABB) , 2013, DOI: 10.4236/abb.2013.47103
Abstract: The cellular strategy leading to formation of neuronal circuits in the rodent barrel cortex is still a matter of controversy. Both selective and constructive mechanisms have been proposed. The selective mechanism involves an overproduction of neuronal processes and synapses followed by activity dependent pruning. Conversely, a constructive mechanism would increase the number of axons, dendrites, and synapses during development to match functionality. In order to discern the contributions of these two mechanisms in establishing a neuronal circuit in the somatosensory cortex, morphometric analysis of dendritic and axonal arbor growth was performed. Also, the number of synapses was followed by electron microscopy during the first month of life. We observed that axonal and dendritic arbors retracted distal branches, and elongated proximal branches, resulting in increased arbor complexity. This neuronal remodeling was accompanied by the steady increase in the number of synapses within barrel hollows. Similarly, the content of molecular markers for dendrites, axons and synapses also increased during this period. Finally, cytochrome oxidase activity rose with age in barrels indicating that the arbors became more complex while synapse density and metabolic demands increased. Our results support the simultaneous use of both selective and constructive mechanisms in establishing the barrel cortex circuitry.

Remoción de semillas, herbivoría y reclutamiento de plántulas de Brosimum alicastrum (Moraceae) en sitios con manejo forestal contrastante de la selva Maya, Quintana Roo, México
Gutiérrez-Granados, Gabriel;Dirzo, Rodolfo;
Boletín de la Sociedad Botánica de México , 2009,
Abstract: the impact of timber extraction was evaluated on brosimum alicastrum, particularly on seed removal, recruitment and seedling herbivory. a series of experimental exclusions were established in logged and unlogged areas. results showed that seed removal and recruitment were larger in timber extraction areas. nonetheless foliar damage was more intense in unlogged areas and it showed a denso-dependency, whereas in timber extraction areas density effects were not significative. therefore establishment of plants differs according to management conditions. results suggest that timber extraction affects plant establishment via alteration of denso-dependency what in the long-term would cause an over-representation of some species affecting diversity of tropical rain forests.
Meta-análisis de efectividad de la colecistectomía laparoscópica frente a la abierta
Olaya Pardo,Catalina; Carrasquilla Gutiérrez,Gabriel;
Revista Colombiana de Cirugía , 2006,
Abstract: a meta-analysis was carried out to compare the efficacy of laparoscopic cholecystectomy versus the traditional surgical procedure. fortyone studies published between 1990 and 2003 were included in the analysis to assess mortality, complications, length of hospital stay after the surgery, time length of the procedure, time to reinitiate food intake, and number of days out of work. the analysis was carried out by using the dersimonian's and laird's random effect model for calculating the weighted relative risk (rr) for dichotomous and mean differences (md) for continuous variables. non-randomized prospective cohort studies, studies including only patients with chronic cholecystitis, studies including both chronic and acute cholecystitis, studies of patients older than 65 years of age and studies carried out after 1995 showed lower risk of complications for laparoscopic cholecystectomy. the studies carried out after 1995 and those in europe reported lower risk of death. studies after 1995 reported 4.99 shorter days of length of stay for the laparoscopic procedure. in none of the sub-groups we found evidence that favors the open cholecystectomy.
Meta-análisis de efectividad de la colecistectomía laparoscópica frente a la abierta Meta-analysis of the effectiveness of laparoscopic cholecystectomy versus open cholecystectomy
Catalina Olaya Pardo,Gabriel Carrasquilla Gutiérrez
Revista Colombiana de Cirugía , 2006,
Abstract: Este documento recoge, por medio de un meta-análisis, los resultados de efectividad de la colecistectomía laparoscópica frente a la colecistectomía abierta, con el objeto de generar mayor evidencia a este respecto. Cuarenta y un estudios publicados entre 1990 y 2003 se consideraron en el análisis, cuyas variables medidas fueron frecuencia de mortalidad, frecuencia de complicaciones, días de estancia hospitalaria posoperatoria, días de incapacidad del paciente, tiempo quirúrgico y días de restablecimiento de la alimentación. El análisis se condujo mediante el modelo de efectos aleatorios de DerSimonian and Laird como una medida ponderada de riesgo relativo (RR) en el caso de variables dicotómicas y de diferencia de medias (MD) en el caso de variables continuas. Estudios de dise o prospectivo no aleatorizado, estudios de pacientes con colecistitis crónica, estudios de pacientes con colecistitis crónica y aguda, estudios de pacientes mayores de 65 a os y estudios ejecutados después de 1995, revelaron menor riesgo de complicación con la laparoscopia. Estudios realizados después de 1995 y otros hechos en Europa evidenciaron menor riesgo de muerte con la laparoscopia. Estudios ejecutados después de 1995 reportaron una estancia hospitalaria menor en 4,99 días en procedimientos bajo técnica laparoscópica. En ninguno de los subgrupos analizados se encontró evidencia a favor de la técnica abierta. A meta-analysis was carried out to compare the efficacy of laparoscopic cholecystectomy versus the traditional surgical procedure. Fortyone studies published between 1990 and 2003 were included in the analysis to assess mortality, complications, length of hospital stay after the surgery, time length of the procedure, time to reinitiate food intake, and number of days out of work. The analysis was carried out by using the DerSimonian's and Laird's Random Effect Model for calculating the weighted relative risk (RR) for dichotomous and mean differences (MD) for continuous variables. Non-randomized prospective cohort studies, studies including only patients with chronic cholecystitis, studies including both chronic and acute cholecystitis, studies of patients older than 65 years of age and studies carried out after 1995 showed lower risk of complications for laparoscopic cholecystectomy. The studies carried out after 1995 and those in Europe reported lower risk of death. Studies after 1995 reported 4.99 shorter days of length of stay for the laparoscopic procedure. In none of the sub-groups we found evidence that favors the open cholecystectomy.
REMOCIóN DE SEMILLAS, HERBIVORíA Y RECLUTAMIENTO DE PLáNTULAS DE BROSIMUM ALICASTRUM (MORACEAE) EN SITIOS CON MANEJO FORESTAL CONTRASTANTE DE LA SELVA MAYA, QUINTANA ROO, MéXICO
GABRIEL GUTIéRREZ-GRANADOS,RODOLFO DIRZO
Boletín de la Sociedad Botánica de México , 2009,
Abstract: En este trabajo se evaluó el impacto de la extracción forestal sobre la remoción de semillas, herbivoría y establecimiento de Brosimum alicastrum. Para esto, se utilizaron una serie de exclusiones experimentales colocadas en sitios con manejo y sin manejo forestal. Los resultados muestran que la remoción de semillas y el establecimiento de B. alicastrum fue mayor en las zonas de extracción forestal. La herbivoría fue más intensa en las zonas de reserva y estuvo asociada a una mayor abundancia de B. alicastrum lo que sugiere la existencia de efectos denso-dependientes en las zonas de reserva; en las zonas de extracción forestal no existió esta asociación, lo que puede estar explicando el establecimiento diferencial entre condiciones de admanejo. Los resultados indican que la extracción forestal puede alterar procesos denso-dependientes y causar la sobre representación de algunas especies afectando a largo plazo la diversidad de las selvas.
Molecular signaling of 5-HT1A and presence of serotonergic cells in the fetal cerebral cortex  [PDF]
Alfonso B. M. de Oca, Gabriel M. Gutiérrez, Jorge H. Rodríguez
World Journal of Neuroscience (WJNS) , 2013, DOI: 10.4236/wjns.2013.32011
Abstract:

Early appearance of the serotonergic system in the fetal brain and the various effects of serotonin (5-HT) on brain morphogenesis, have given support to a neurotrophic role of serotonin. This function of serotonin is accomplished through a system of serotonin nerve terminals in the target regions that involves various 5-HT receptors. In visual, auditory and somatosensory cortex an early and intense serotonergic innervation is particularly important. The neuronal somata of these terminals are normally located in the mesencephalon and they have not been observed in the maturing cerebral cortex, neither in the adult brain. By using immunolabeling techniques, fluorescence and confocal microscopy, we observe the presence of both, 5-HT terminals and 5-HT cells in mesencephalon (Me, E17) and in the neopallium (Np, E13-E16) cocultures. Cells immunopositive to 5-HT and to tryptophan-5-hydroxilase are also observed in the Np on day 12 of culture. These results concerning the unexpected presence of serotonergic cells in the fetal cerebral cortex are interesting and may be of importance in corticogenesis. As it happens with other elements of the serotonergic system, the presence of these phenotypically serotonergic cells in the early cerebral cortex may be transitory and probably supporting cortex maturation processes. The molecular signaling path of the 5-HT1A receptor has also been identified.

Interacciones macho-hembra del pulpo rojo patagónico Enteroctopus megalocyathus (Cephalopoda: Octopodidae) durante el comportamiento de apareamiento
Gutiérrez,Ranferi; Farías,Ana; Yany,Gabriel; Uriarte,Iker;
Latin american journal of aquatic research , 2012, DOI: 103856/vol40-issue3-fulltext-27
Abstract: the mating behavior of eight couples of enteroctopus megalocyathus was evaluated under laboratory conditions by videotaping for 24 h. the precopulatory behavior (cp) was characterized by three patterns (swimming, exhibition and contact) and copulatory behavior (cc) was characterized by display of a single pattern (copulation). of the total interaction time between octopuses, 34.4% corresponds to cp and 65.6% corresponds to cc. between times of males and females were not significantly different by pattern. in all events, compared to each other for the duration, presented the following order: copulation > contact > exhibition > swimming. there was a trend towards longer periods of mating where the female weight was higher than the male, suggesting that female weight is a determining factor in the duration of mating encounters.
Acceso vascular inusual para cateterismo cardiaco en pacientes con cardiopatía congénita compleja: reporte de un caso Unusual vascular access for cardiac catheterization in patients with complex congenital heart disease: a case report
Walter Mosquera,Jaiber Gutiérrez,Gabriel Santiago,Juan P Carbonell
Revista Colombiana de Cardiología , 2012,
Abstract: La obtención del acceso vascular es fundamental en la realización de diferentes procedimientos de cateterismo cardíaco. Los cateterismos a repetición y las cirugías cardíacas múltiples pueden resultar en una marcada incidencia de pérdida de estos sitios de acceso, razón por la cual, en algunas oportunidades, es necesario el uso de técnicas no convencionales. Se reporta el caso de un paciente de un a o de edad en quien fue necesario el abordaje retroperitoneal de la arteria ilíaca común. Obtaining vascular access is essential in the realization of different cardiac catheterization procedures. The recurrent catheterizations and multiple cardiac surgeries may result in marked incidence of loss of these access sites, which is why sometimes it is necessary to use unconventional techniques. We report the case of a one year old patient that necessitated the retroperitoneal approach of the common iliac artery.
Tetralogía de Fallot asociada a síndrome de cimitarra Tetralogy of Fallot associated with scimitar syndrome
Jaiber Gutiérrez,Walter Mosquera,Gabriel Santiago,Claudia Guerrero
Revista Colombiana de Cardiología , 2012,
Abstract: Se expone el caso de un ni o de catorce meses de edad, con tetralogía de Fallot asociada a síndrome de cimitarra, cuyo diagnóstico se realizó mediante ecocardiografía, cateterismo cardiaco y angio-TAC. Se hace referencia a las consideraciones clínicas y quirúrgicas de este caso que hasta la fecha es el quinto reportado en la literatura. We describe the case of a fourteen-month-old boy with tetralogy of Fallot associated with scimitar syndrome, whose diagnosis was made by echocardiography, cardiac catheterization and angio-CT. We relate the clinical and surgical considerations in this case which is so far the fifth reported in the literature.
Interacciones macho-hembra del pulpo rojo patagónico Enteroctopus megalocyathus (Cephalopoda: Octopodidae) durante el comportamiento de apareamiento Male-female interactions of Patagonian red octopus Enteroctopus megalocyathus (Cephalopoda: Octopodidae) during mating behavior
Ranferi Gutiérrez,Ana Farías,Gabriel Yany,Iker Uriarte
Latin american journal of aquatic research , 2012,
Abstract: Se evalúa, en condiciones de laboratorio, el comportamiento de apareamiento de ocho parejas de Enteroctopus megalocyathus mediante videograbaciones durante 24 h. El comportamiento precopulatorio (CP) se caracterizó por presentar tres eventos (natación, exhibición y contacto) y el comportamiento copulatorio (CC) se caracterizó por mostrar un solo evento (cópula). Del tiempo total de interacción de las parejas, el 34,4% correspondió al CP y el 65,6% correspondió al CC. Entre los tiempos de machos y hembras no hubo diferencias significativas por evento. Al compararse todos los eventos entre sí en relación al tiempo de duración, se presentó el siguiente orden: cópula > contacto > exhibición > natación. Se observó una tendencia a periodos de apareamiento más largos donde el peso de la hembra fue superior al macho, sugiriendo que el peso de la hembra es un factor determinante en la duración de los encuentros de apareamiento. The mating behavior of eight couples of Enteroctopus megalocyathus was evaluated under laboratory conditions by videotaping for 24 h. The precopulatory behavior (CP) was characterized by three patterns (swimming, exhibition and contact) and copulatory behavior (CC) was characterized by display of a single pattern (copulation). Of the total interaction time between octopuses, 34.4% corresponds to CP and 65.6% corresponds to CC. Between times of males and females were not significantly different by pattern. In all events, compared to each other for the duration, presented the following order: copulation > contact > exhibition > swimming. There was a trend towards longer periods of mating where the female weight was higher than the male, suggesting that female weight is a determining factor in the duration of mating encounters.
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