952 research outputs found

    Effects of pyruvate administration on infarct volume and neurological deficits following permanent focal cerebral ischemia in rats

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    Recent experimental evidences indicate that pyruvate, the final metabolite of glycolysis, has a remarkable protective effect against different types of brain injury. The purpose of this study was to assess the neuroprotective effect and the neurological outcome after pyruvate administration in a model of ischemic stroke induced by permanent middle cerebral artery occlusion (pMCAO) in rats. Three doses of pyruvate (250, 500 and 1000 mg/kg, i.p.) or vehicle were administered intraperitoneally 30 min after pMCAO. In other set of experiments, pyruvate was given either before, immediately after ischemia or in a long-term administration paradigm. Functional outcome, mortality and infarct volume were determined 24 h after stroke. Even when the lowest doses of pyruvate reduced mortality and neurological deficits, no concomitant reduction in infarct volume was observed. The highest dose of pyruvate increased cortical infarction by 27% when administered 30 min after pMCAO. In addition, when pyruvate was given before pMCAO, a significant increase in neurological deficits was noticed. Surprisingly, on the contrary of what was found in the case of transient global ischemia, present findings do not support a great neuroprotective role for pyruvate in permanent focal cerebral ischemia, suggesting two distinct mechanisms involved in the effects of this glycolytic metabolite in the ischemic brain

    Are Basophils Important Mediators for Helminth-Induced Th2 Immune Responses? A Debate

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    Helminth parasites induce Th2 immune responses. Immunological mechanisms leading to Th2 induction are mainly dependent on IL-4. However, early source of IL-4 has not been precisely identified. Noticeably, basophils seem to be important mediators for inducing and maintaining the Th2 response probably because they secrete IL-4 and exert functions similar to APCs. Nevertheless, recent experimental evidence points that DCs could be also significant participants during this process. The involvement of basophils during memory responses is also discussed

    Post-ischaemic treatment with the cyclooxygenase-2 inhibitor nimesulide reduces blood-brain barrier disruption and leukocyte infiltration following transient focal cerebral ischaemia in rats

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    Several studies suggest that cyclooxygenase (COX)-2 plays a pivotal role in the progression of ischemic brain damage. In the present study, we investigated the effects of selective inhibition of COX-2 with nimesulide (12 mg/kg) and selective inhibition of COX-1 with valeryl salicylate (VAS, 12-120 mg/kg) on prostaglandin E2 (PGE2) levels, myeloperoxidase (MPO) activity, Evans Blue (EB) extravasation and infarct volume in a standardized model of transient focal cerebral ischemia in the rat. Postischemic treatment with nimesulide markedly reduced the increase in PGE2 levels in the ischemic cerebral cortex 24 h after stroke and diminished infarct size by 48 % with respect to vehicle-treated animals after 3 days of reperfusion. Furthermore, nimesulide significantly attenuated the blood-brain barrier (BBB) damage and leukocyte infiltration (as measured by EB leakage and MPO activity, respectively) seen at 48 h after the initial ischemic episode. These studies provide the first experimental evidence that COX-2 inhibition with nimesulide is able to limit BBB disruption and leukocyte infiltration following transient focal cerebral ischemia. Neuroprotection afforded by nimesulide is observed even when the treatment is delayed until 6 h after the onset of ischemia, confirming a wide therapeutic window of COX-2 inhibitors in experimental stroke. On the other hand, selective inhibition of COX-1 with VAS had no significant effect on the evaluated parameters. These data suggest that COX-2 activity, but not COX-1 activity, contributes to the progression of focal ischemic brain injury, and that the beneficial effects observed with non-selective COX inhibitors are probably associated to COX-2 rather than to COX-1 inhibition

    Spectroscopic and dynamical properties of comet C/2018 F4, likely a true average former member of the Oort cloud

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    The population of comets hosted by the Oort cloud is heterogeneous. Most studies in this area focused on highly active objects, those with small perihelion distances or examples of objects with peculiar physical properties and/or unusual chemical compositions. This may have produced a biased sample of Oort cloud comets in which the most common objects may be rare, particularly those with perihelia well beyond the orbit of the Earth. Within this context, the known Oort cloud comets may not be representative of the full sample. Here, we study the spectral properties in the visible region and the cometary activity of Comet C/2018 F4 (PANSTARRS). We also explore its orbital evolution with the aim of understanding its origin within the context of known minor bodies moving along nearly parabolic or hyperbolic paths. We present observations obtained with the 10.4 m Gran Telescopio Canarias (GTC), derive the spectral class and visible slope of C/2018 F4 and characterise its level of cometary activity. Direct N-body simulations are carried out to explore its orbital evolution. The absolute magnitude of C/2018 F4 is Hr=13.62+/-0.04. Assuming a pV=0.04 its diameter is D<10.4 km. The object presents a conspicuous coma, with a level of activity comparable to those of other comets observed at similar heliocentric distances. Comet C/2018 F4 has a visible spectrum consistent with that of an X-type asteroid, and has a spectral slope S'=4.0+/-1.0 %/1000\AA and no evidence of hydration. The spectrum matches those of well-studied primitive asteroids and comets. The analysis of its dynamical evolution prior to discovery suggests that C/2018 F4 is not of extrasolar origin. Although the present-day heliocentric orbit of C/2018 F4 is slightly hyperbolic, its observational properties and past orbital evolution are consistent with those of a dynamically old comet with an origin in the Oort cloud.Comment: 6 pages, 5 figures. In pres

    Neuroprotective efficacy of nimesulide against hippocampal neuronal damage following transient forebrain ischemia

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    Cyclooxygenase-2 is involved in the inflammatory component of the ischemic cascade, playing an important role in the delayed progression of the brain damage. The present study evaluated the pharmacological effects of the selective cyclooxygenase-2 inhibitor nimesulide on delayed neuronal death of hippocampal CA1 neurons following transient global cerebral ischemia in gerbils. Administration of therapeutically relevant doses of nimesulide (3, 6 and 12 mg/kg; i.p.) 30 min before ischemia and at 6, 12, 24, 48 and 72 h after ischemia significantly (P<0.01) reduced hippocampal neuronal damage. Treatment with a single dose of nimesulide given 30 min before ischemia also resulted in a significant increase in the number of healthy neurons in the hippocampal CA1 sector 7 days after ischemia. Of interest is the finding that nimesulide rescued CA1 pyramidal neurons from ischemic death even when treatment was delayed until 24 h after ischemia (34+/-9% protection). Neuroprotective effect of nimesulide is still evident 30 days after the ischemic episode, providing the first experimental evidence that cyclooxygenase-2 inhibitors confer a long-lasting neuroprotection. Oral administration of nimesulide was also able to significantly reduce brain damage, suggesting that protective effects are independent of the route of administration. The present study confirms the ability of cyclooxygenase-2 inhibitors to reduce brain damage induced by cerebral ischemia and indicates that nimesulide can provide protection when administered for up to 24 h post-ischemia

    Inteligencia emocional y aprendizaje significativo en los estudiantes de una Institución Educativa de San Isidro, 2022

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    La elaboración del presente trabajo investigativo puntualizo su objetivo establecer la relación de la inteligencia emocional y aprendizaje significativo en los estudiantes de una Institución Educativa de San Isidro, 2022. Su proceso de desarrollo estuvo enfocado en el enfoque cuantitativo, de diseño no experimental y nivel correlacional, en la cual se consideró una cantidad poblacional de 420 estudiantes y una muestra de 202 alumnos de 4to y 5to de secundaria. Los principales resultados ofrecen un coeficiente de correlación de Rho de Spearman = ,573, donde se evidencia un ρ = 0.000 (ρ < 0.05) con lo cual se demuestra la existencia de una conexión positiva y significativa entre la variable Inteligencia emocional y aprendizaje significativo. En donde se concluye que al existir un incremento de la Inteligencia emocional se favorece el Aprendizaje significativo

    The seed of magnetic monopoles in the early inflationary universe from a 5D vacuum state

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    Starting from a 5D Riemann flat metric, we have induced an effective 4D Hermitian metric which has an antisymmetric part which is purely imaginary. We have worked an example in which both, non-metricity and contorsion are zero. We obtained that the production of monopoles should be insignificant at the end of inflation and the tensor metric should come asymptotically diagonal and describing a nearly 4D de Sitter expansion.Comment: Version accepted in Physics Letters

    Hernia obturatriz izquierda, obstrucción intestinal y hernia inguinal bilateral: Reporte de caso

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    Obturator hernia has an incidence of less than 1% of all abdominal wall hernias, it is predominantly observed in elder women and it is characterized by protrusion of intra-abdominal viscera into the shutter hole. The preoperative diagnosis is difficult due to the lack of external manifestations, nonspecific symptoms and lack of clinical suspicion. Delaying diagnosis and treatment is associated with high mortality. We report the case of a female patient with a complicated obturator hernia with concomitant bilateral inguinal hernias that underwent minimally invasive surgery with no complications and a seven day stay in hospital.La hernia obturatriz tiene una incidencia de menos del 1% de todas las hernias de la pared abdominal, se presentan predominantemente en mujeres de edad avanzada y se caracteriza por la protrusión de las vísceras intraabdominales hacia el agujero obturador. El diagnóstico preoperatorio suele ser difícil debido a la falta de manifestaciones externas obvias, síntomas y signos inespecíficos y falta de sospecha clínica. El retraso en el diagnóstico y en el tratamiento de esta afección generalmente conduce a una alta tasa de mortalidad. Reportamos el caso de una paciente con hernia obturatriz complicada y hernia inguinal bilateral, la cual fue resuelto por cirugía mínimamente invasiva, no hubo complicaciones en la evolución postoperatoria, siendo su estancia hospitalaria siete días
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