When to use a prophylactic mesh after stoma closure: a case-control study.

PURPOSE: The closure of a stoma is frequently associated with an acceptable morbidity and mortality. One of the most frequent complications is incisional hernia at the stoma site, which occurs in 20%-40% of cases, higher than incisions in other parts of the abdomen. The objective of this study was to identify the risk factors associated with the presentation of incisional hernia after stoma closure, this in order to select patients who are candidates for prophylactic mesh placement during closure. METHODS: An unpaired case-control study was conducted. This study involved 164 patients who underwent a stoma closure between January 2014 and December 2019. Associated factors for the development of incisional hernia at the site of the stoma after closure were identified, for which it was performed a logistic regression analysis. RESULTS: 41 cases and 123 controls were analyzed, with a mean follow-up of 35.21 ± 18.42 months, the mean age for performing the stoma closure was 65.28 ± 14.07 years, the most frequent cause for performing the stoma was malignant disease (65.85%). Risk factor for the development of incisional hernia at the stoma site after its closure was identified as a history of parastomal hernia (OR 5.90, CI95% 1.97-17.68). CONCLUSIONS: The use of prophylactic mesh at stoma closure should be considered in patients with a history of parastomal hernia since these patients present a significantly higher risk of developing a hernia.

Novel edible toys as iron carrier to prevent iron deficiency of postweaned pigs.

The current preventive treatment for iron deficiency in pigs is inefficient, resulting in a high prevalence of iron-deficient or anemic postweaned pigs. The aim of this study was to develop and characterize edible toys (ETs) to be used as oral iron supplements, and to assess their effect on feeding behavior and iron status of postweaned pigs. Three types of ETs, varying in sweetness, were produced by ionic gelation, using whey, sodium alginate, ferrous sulfate and atomized bovine erythrocytes. ET control (ETC) was developed without sweetener, ET1 contained 15% w/v sucrose and ET2 contained 0.03% w/v of Sucram (98% sodium saccharin, 1% neosperidine dihydrocalcone and 1% maltol). ETs were mainly composed of carbohydrates and protein, with a similar concentration of iron (2.2-2.7 mg/g). The ETs were offered to 24 postweaned pigs to measure acceptability and preference. The animals preferred ETC and ET2 over ET1. To assess the nutritional benefit of the ETs, 24 postweaned pigs were distributed into three groups: ETC (without iron), ETC-Fe (ETC with iron) and ET2-Fe (with iron and Sucram). Iron-loaded ET (ETC-Fe and ET2-Fe) significantly increased the concentration of red blood cells (from 6.1 to 7.5·106 x mm3 for ETC-Fe and from 6.2 to 7.8 for ET2-Fe), hematocrit (from 32.8 to 37.9% for ETC-Fe and from 32.3 to 35.1 for ET2-Fe), serum iron (from 28.6 to 120.6 µmol/L for ETC-Fe and from 34.9 to 145.4 for ET2-Fe) and serum ferritin (from 7.8 to 18.5 µg/L for ETC-Fe and from 8.1 to 20.2 for ET2-Fe). In conclusion, the ETs developed in this study were accepted by the pigs and provided adequate iron to improve the iron status of postweaned pigs.

Otro desafío de la naturaleza: el nuevo coronavirus virología y fisiopatología del SARS-COV-2 / Another challenge of nature: the new coronavirus virology and physiopathology of SARS-CoV-2

The recent outbreak of emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19) has been brought to global attention in the search of knowledge about the virus and its pathogenesis. The immune response is essential to control and eliminate the infection, however, maladjusted immune responses may result in severe disease fisiopathology. Gaining a deeper understanding of the interaction between SARS-CoV-2 and the immune systems of the hosts may help us anticipate the development of persistent pulmonary inflammation and, why not, be the first step to therapeutic success and trying to save more lives. In this review, we provide an update on CoV virology and our vision of pathogenesis understanding it from the stages of infection, without forgetting the cytokine storm resulting from the interaction of the virus with ACE2 receptors widely distributed in the body.

La reciente emergencia de síndrome de distrés respiratorio agudo producido por coronavirus 2 (SARS-CoV-2), enfermedad denominada COVID-19 ha traído la atención mundial a la búsqueda de conocimiento sobre este virus y su patogenia. La respuesta inmune es esencial para controlar y erradicar la infección, sin embargo, las respuestas inmunes descontroladas pueden resultar en la fisiopatología de la enfermedad grave. Lograr una comprensión más profunda de la interacción entre SARS-COV-2 y el sistema inmune de los huéspedes podría ayudar a anticiparnos al desarrollo de una inflamación pulmonar persistente causada por el SARS-CoV-2, y por qué no, ser la puerta de entrada al éxito terapéutico e intentar salvar mayor número de vidas. En esta revisión, proporcionamos una actualización sobre la virología y nuestra visión de la patogenia, entendiéndola desde las fases o etapas de la infección, sin olvidar el estallido de citoquinas resultantes de la interacción del virus con los receptores ACE2 ampliamente distribuidos en el organismo.

Infección respiratoria por adenovirus en pediatría: de ayer a hoy / Adenovirus pediatric respiratory infection: past and present

Acute respiratory infections represent a world pediatric health burden. RSV, influenza and adenoviruses are among the most frequent causative agents. Adenoviruses usually produce upper respiratory infections, but they can be responsible for acute lower respiratory infection in children with severe clinical outcome. It is necessary a special clinical and epidemiological organization to avoid nosocomial adenovirus local outbreaks. Rapid diagnose, done by immunofluorescence assay and PCR, individual case isolation and supportive therapy are necessary for an appropriate management. The increasing immune compromised population represents a challenge for the adenovirus diagnosis with quantitative PCR and for nosocomial infection control and potential antiviral treatment.

Las infecciones respiratorias agudas son un problema prioritario mundial de morbimortalidad infantil y son causadas predominantemente por virus, entre los que destacan el virus respiratorio sincicial (VRS), virus influenza (FLU) y adenovirus (ADV). Los ADV normalmente causan infecciones respiratorias altas, pero pueden provocar infecciones bajas muy graves, que dejan secuelas y tienen alta letalidad. Requieren un manejo clínico y epidemiológico especial para evitar los graves brotes nosocomiales observados en Latinoamérica. Esto incluye un diagnóstico rápido hecho con técnicas de inmunodiagnóstico y reacción en cadena polimerasa (PCR), aislamiento individual del paciente y terapia de soporte. En pacientes inmunocomprometidos, la infección por ADV representa un gran desafío para el diagnóstico, con uso de PCR cuantitativo (qPCR) y eventual tratamiento antiviral. El objetivo de esta revisión es el de actualizar las propiedades, patogenia, epidemiología y diagnóstico del ADV, con énfasis en los cuadros respiratorios de mayor morbimortalidad que se producen en algunos niños.

Maternal and postnatal high-fat diets with high ω6 : ω3 ratios affect the reproductive performance of male offspring in the mouse.

High-fat diets (HFDs) are an acknowledged risk factor for male subfertility, but the underlying mechanisms remain unclear. In the present study we compared the effects of two HFDs with different ω6:ω3 ratios, one enriched with soy oil (SOD; ω6:ω3=9.62) and another enriched with sunflower oil (SFOD; ω6:ω3=51.55), with those of a commercial diet (CD; ω6:ω3=19.87), supplied from pregnancy to adulthood, on morphometric parameters and reproductive performance in adult male mice (recommended ω6:ω3 for rodents=1-6). Bodyweight was significantly higher in the SFOD than CD group, and relative testicular weight was significantly lower in the SFOD than the other two groups. SFOD altered sperm performance: it reduced sperm viability (mean±s.e.m.; 76.00±1.35% vs 82.50±1.45% and 80.63±1.00% in the SFOD vs CD and SOD groups respectively; P<0.05) and increased the percentage of immature spermatozoa (71.88±7.17% vs 51.38±5.87% and 48.00±5.72% in the SFOD vs CD and SOD groups respectively; P<0.05). The epididymal ω6:ω3 ratio was higher in the SFOD versus CD and SOD groups, whereas the unsaturation index was higher in the SOD and SFOD groups than in CD group. Sperm membrane integrity was diminished in both the SOD and SFOD groups, but there was no difference in sperm reactive oxygen species production in these two groups compared with the CD group. The fertilisation rate was lower in the SFOD compared with the CD and SOD groups. In conclusion, although both HFDs affected sperm quality, the fertilising ability was more altered by the excessive dietary ω6:ω3 ratio than by the net ω6 content.

El virus respiratorio sincicial: patógeno de niños... y de grandes / Respiratory syncytial virus: a pathogen for the small ones and the big ones

Desde el descubrimiento del virus respiratorio sincicial (VRS) en 1956, se ha demostrado en todo el mundo su impacto como el principal causante de infecciones respiratorias agudas bajas (IRAB) que requieren hospitalización en el lactante. Posteriormente se ha descrito que una inadecuada respuesta inmune favorece reinfecciones en la infancia. Más recientemente, numerosos trabajos epidemiológicos lo han asociado a IRAB en adultos, especialmente de tercera edad y en ciertos pacientes inmunocomprometidos. Se ha avanzado en el conocimiento de la estructura y función de los diferentes componentes del VRS, lo que ha permitido facilitar su diagnóstico y avanzar en estrategias de desarrollo de antivirales y vacunas. En efecto, el diagnóstico de laboratorio de VRS es muy simple en niños, por su alta excreción viral, pero para demostrar su participación en adultos se requieren técnicas de alta sensibilidad. La patogenia de la infección es muy compleja y muchos aspectos todavía no se han aclarado. Intervienen factores dependientes del virus -cepa, dosis infectiva, capacidad del virus de inhibir la respuesta inmune- y del hospedero humano, como edad, enfermedades concomitantes, integridad del aparato inmune y otros. Se menciona que otros factores como frío, humedad ambiental, contaminación aérea, hacinamiento, también actuarían en combinación con los inicialmente mencionados. Es necesario conocer los mecanismos responsables de la adquisición de inmunidad contra el VRS para entender las estrategias usadas en el intento de desarrollar vacunas, cuyos esfuerzos son todavía infructuosos. Actualmente se conoce bastante del VRS como patógeno de niños. Sin embargo, cada día se documenta más su participación en enfermedades de adultos, por lo que haremos un resumen para promover su consideración como posible patógeno respiratorio.

Since respiratory syncytial virus (RSV) was identified in 1956, its impact as the main cause of severe acute lower respiratory infections in infants has been shown. Studies about RSV immunopathogenesis have demonstrated that the host immune response is important in protecting from re-infections. The presence of RSV in exacerbation of chronic diseases as COPD and bronchial asthma in adults and its severity in cases with immunodeficiency has been also related to an inadequate response. The actual knowledge on the molecular structure and functions of the virus has allowed to improve diagnosis and to develop new strategies for vaccines and antiviral drugs. The etiologic diagnosis in children is easier than in adults due to the higher viral shedding; therefore techniques based on antibody reactions (immunofluorescence, immunocromatography, etc) are good enough in this group. By contrast, in adults, highly sensitive molecular techniques are needed. Although the advances in understanding the pathogenesis process in neonates and infants, many pathogenic factors still need to be elucidated. The virus strains, viral loads and immune response have been described as important players; however, the changes on the host immunity to RSV according to age and co-morbidities associated to severity of illness needs to be explored. RSV has been known as a children pathogen, nowadays this agent is being recognized as an important agent in adults, especially in those with chronic diseases, immunodeficiency and in immune-senescence.

Comparación del modelo de Cortínez y de Schnider en perfusión de propofol controlada por objetivo de 3 mcg/ml, a biofase, en voluntarios sanos / Comparison of the Cortínez and the Schnider models with a targeted effect-site TCI of 3 mcg/ml in biophase in healthy volunteers

Objetivo. Comparar clínicamente los modelos de Schnider y Cortínez con sistemas «TCI», para la perfusión de propofol a concentración en biofase de 3 mcg/ml en voluntarios sanos. Material y método. Se estudió prospectivamente a 10 voluntarios sanos en 2 ocasiones. Se administró propofol con el modelo de Cortínez o Schnider según asignación aleatorizada. Se compararon tiempos y concentraciones de propofol alcanzadas al momento de pérdida y recuperación de consciencia (LOC y ROC), masa de fármaco administrada, valores de BIS y variables hemodinámicas. El análisis estadístico fue con Wilcoxon pareado. Una p ≤ 0,05 fue considerada significativa. Resultados. El bolo inicial de propofol fue mayor (1,4 [1,3-1,6] versus 0,9 [0,7-1,3] mg/kg; p=0,005) y el LOC ocurrió antes (1,33 [0,67-6,83] versus 3,87 [1,66-11,08] min; p=0,02) con el modelo de Cortínez comparado con el modelo de Schnider. El modelo de Cortínez predice una concentración en biofase al LOC de 2,6mcg/ml (1,65-3,0). Con Schnider, el LOC ocurre 3,87min (1,66-11,8) después de alcanzado el objetivo de 3mcg/ml (p=0,001). Los valores de BIS, las velocidades de perfusión y las variables hemodinámicas fueron similares con ambos modelos a los 20 min de perfusión (p>0,5). La recuperación (ROC) fue más larga con el modelo de Cortínez (11,6 [8,1-16,2] vs. 8,5 [4,7-15,5] min; p=0,003). Conclusiones. El modelo de Cortínez es una buena alternativa al modelo de Schnider para su uso en TCI con objetivo en biofase en sujetos normopeso. Con el objetivo utilizado, las concentraciones en biofase predichas con la Ke0 más lenta incorporada en el modelo de Cortínez permiten discriminar mejor el momento del LOC en la inducción (AU)

Objective. To compare the Cortínez and Schnider models in effect-site TCI mode (3 mcg/ml) in healthy volunteers. Methods. Ten healthy volunteers were prospectively studied on 2 occasions. Propofol was administered with the Cortínez or the Schnider models, as randomly assigned. Times and predicted concentrations at the time of loss and recovery of consciousness (LOC and ROC), mass of drug administered, BIS, and haemodynamic variables were compared. Statistical analysis was with paired Wilcoxon test. A P<.05 was considered significant. Results. The propofol bolo was higher (1.4 [1.3-1.6] versus 0.9 [0.7-1.3] mg/kg, P=.005) and the LOC occurred earlier (1.33 [0.67-6.83] versus 3.87 [1.66-11.08] minutes, P=.02) with the Cortínez model compared to the Schnider model. With the Cortínez model, LOC occurred at an effect site concentrations of 2.6 (1.65-3.0) mcg/ml. With the Schnider model, LOC occurred at 3.87 min (1.66-11.8) after reaching the target of 3 mcg/ml. (P=.001). BIS values, infusion rates, and haemodynamic variables were similar between models after 20minutes of infusion (P>.5). Recovery (ROC) was longer with the Cortínez model (11.6 [8.1-16.2] vs. 8.5 [4.7-15.5] min, P=.003). Conclusions. The Cortínez model is a good alternative to the Schnider model for use in effect-site TCI mode in normal weight subjects. With the target used in this study (3 mcg/ml), the slower Ke0 incorporated into the Cortínez model better discriminated the LOC time (AU)

Resonant surface plasmon-exciton interaction in hybrid MoSe2@Au nanostructures.

In this work we investigate the interaction between plasmonic and excitonic resonances in hybrid MoSe2@Au nanostructures. The latter were fabricated by combining chemical vapor deposition of MoSe2 atomic layers, Au disk processing by nanosphere lithography and a soft lift-off/transfer technique. The samples were characterized by scanning electron and atomic force microscopy. Their optical properties were investigated experimentally using optical absorption, Raman scattering and photoluminescence spectroscopy. The work is focused on a resonant situation where the surface plasmon resonance is tuned to the excitonic transition. In that case, the near-field interaction between the surface plasmons and the confined excitons leads to interference between the plasmonic and excitonic resonances that manifests in the optical spectra as a transparency dip. The plasmonic-excitonic interaction regime is determined using quantitative analysis of the optical extinction spectra based on an analytical model supported by numerical simulations. We found that the plasmonic-excitonic resonances do interfere thus leading to a typical Fano lineshape of the optical extinction. The near-field nature of the plasmonic-excitonic interaction is pointed out experimentally from the dependence of the optical absorption on the number of monolayer stacks on the Au nanodisks. The results presented in this work contribute to the development of new concepts in the field of hybrid plasmonics.

Comparison of the Cortínez and the Schnider models with a targeted effect-site TCI of 3 mcg/ml in biophase in healthy volunteers. / Comparación del modelo de Cortínez y de Schnider en perfusión de propofol controlada por objetivo de 3 mcg/ml, a biofase, en voluntarios sanos.

OBJECTIVE: To compare the Cortínez and Schnider models in effect-site TCI mode (3 mcg/ml) in healthy volunteers. METHODS: Ten healthy volunteers were prospectively studied on 2 occasions. Propofol was administered with the Cortínez or the Schnider models, as randomly assigned. Times and predicted concentrations at the time of loss and recovery of consciousness (LOC and ROC), mass of drug administered, BIS, and haemodynamic variables were compared. Statistical analysis was with paired Wilcoxon test. A P<.05 was considered significant. RESULTS: The propofol bolo was higher (1.4 [1.3-1.6] versus 0.9 [0.7-1.3] mg/kg, P=.005) and the LOC occurred earlier (1.33 [0.67-6.83] versus 3.87 [1.66-11.08] minutes, P=.02) with the Cortínez model compared to the Schnider model. With the Cortínez model, LOC occurred at an effect site concentrations of 2.6 (1.65-3.0) mcg/ml. With the Schnider model, LOC occurred at 3.87 min (1.66-11.8) after reaching the target of 3 mcg/ml. (P=.001). BIS values, infusion rates, and haemodynamic variables were similar between models after 20minutes of infusion (P>.5). Recovery (ROC) was longer with the Cortínez model (11.6 [8.1-16.2] vs. 8.5 [4.7-15.5] min, P=.003). CONCLUSIONS: The Cortínez model is a good alternative to the Schnider model for use in effect-site TCI mode in normal weight subjects. With the target used in this study (3 mcg/ml), the slower Ke0 incorporated into the Cortínez model better discriminated the LOC time.

Empty smectic liquid crystals of hard nanorings: Insights from a second-virial theory.

Inspired by recent simulations on highly open liquid crystalline structures formed by rigid planar nanorings, we present a simple theoretical framework explaining the prevalence of smectic over nematic ordering in systems of ring-shaped objects. The key part of our study is a calculation of the excluded volume of such nonconvex particles in the limit of vanishing thickness to diameter ratio. Using a simple stability analysis we then show that dilute systems of ring-shaped particles have a strong propensity to order into smectic structures with an unusual antinematic order while solid disks of the same dimensions exhibit nematic order. Since our model rings have zero internal volume, these smectic structures are essentially empty, resembling the strongly porous structures found in simulation. We argue that the antinematic intralamellar order of the rings plays an essential role in stabilizing these smectic structures.

Desarrollo conceptual de la educación ambiental en el contexto Colombiano / Concepual develoopment of environmental education in the Colombian context

La Educación Ambiental (EA) ha tenido un auge significativo, se trata de una respuesta hacia la necesidad de un cambio social estructural. Sus fundamentos se encuentran tanto en las normas internacionales como locales, y su desarrollo conceptual ha sido amplio y complejo. El objetivo del presente artículo es explorar algunos elementos normativos y conceptuales que fundamentan la EA, así como la adopción de la misma en términos curriculares en Colombia. El método empleado se circunscribe en el análisis documental, razón por la que se abordó una amplia información de la cual se realizaron inferencias de acuerdo al propósito del artículo. Dentro de los resultados, se encontró que la EA ha sido asumida conforme a las características de cada periodo histórico, en especial, del siglo inmediatamente pasado con un gran cúmulo de normas internacionales y nacionales, y que su implementación desde la escuela debe corresponder a una reflexión conjunta y colectiva de todos los actores escolares, tanto en su diseño como implementación. Cualquier enfoque de la educación ambiental resulta válido siempre que corresponda a los objetivos trazados por la escuela en coherencia con las necesidades y problemáticas locales, aquellas de las que son parte los educandos. Se concluye que las normas internacionales y locales en materia de educación ambiental son evidencia de la trascendencia que tiene la protección del medio ambiente y que los enfoques desarrollados desde el terreno conceptual posibiliten el cambio siempre que se integren elementos tanto críticos como cognitivos o socio-cognitivos.

Environmental Education (EE) has had a significant growth as a response to the need for structural social change. Its foundations are found in both international and local standards, and its conceptual development has been extensive and complex. The aim of this article is to explore some statutory and conceptual elements underpinning EE, and its adoption in curricular terms in Colombia. The method used is limited to documentary analysis reason why a wide range of information was addressed from which inferences were made according to the purpose of the article. Among the results, it was found that EE has been taken according to the characteristics of each historical period, particularly since the 70's in the twentieth century with a wealth of international and national standards, and that its implementation from school should respond to a joint and collective reflection of all school actors, both in its design and implementation. Any environmental education approach is valid whenever appropriate to the goals set by the school in line with local needs and problems, which are part of the learners' reality. It is concluded that international and local environmental education norms are evidence of the importance that environmental protection and the approaches developed from the conceptual change make change possible provided that they integrate both critical and cognitive or socio-cognitive elements.

Ambitos de apliaación de la teoría de la modifiabilidad estructural cognitiva de reuven feuerstein / Scopes of aplicaation of reuven feuerstein's structural cognitive modifiability theory

En el artículo se hace una exploración de la teoría de la Modificabilidad Estructural Cognitiva (MEC) de Reuven Feuerstein, en relación con los ámbitos de aplicación de la misma. Para lo anterior, se ha hecho una recopilación de algunos estudios realizados en América Latina, Estados Unidos y Europa, a fin de identificar los diversos escenarios en que la teoría puede tener aplicación. Los resultados evidencian que la teoría de Feuerstein está ligada al concepto de desarrollo humano y que los sistemas creados con base en la MEC permiten reducir la deprivación cultural de muchas personas sin importar los factores endógenos que le afecten.

An exploration of Reuven Feuerstein's cognitive structural modifiability (CSM) theory, in relation to the scope of its application, is made in the article. For this reason, a compilation of studies in Latin America, The United States, and Europe, is made, in order to identify the different scenarios in which the theory can be applied. The results show that Feuerstein's theory is linked to the concept of human development and that the systems created, based on the CSM, allow the reduction of the cultural deprivation of many people, regardless of the endogenous factors that affect it.

Un modelo pedagógico para la educación ambienta desde la perspectiva de la modificabilidad estructural cognitiva / A pedagogical model for enviromental education from the perspective of the cognitive structural modifiability

El artículo tiene como objetivo formular un modelo pedagógico para la educación ambiental atendiendo a la urgencia de crear mecanismos e instrumentos que contribuyan con el desarrollo sostenible del planeta. Para ello, se abordan los principales aspectos teóricos sobre educación, pedagogía, modelos pedagógicos y corrientes de la educación ambiental. Para el diseño se ha analizado e incorporado en el modelo la teoría de la Modificabilidad Estructural Cognitiva y la Experiencia de Aprendizaje Mediado del Reueven Feuerstein. El diseño responde a las exigencias de la sociedad actual y a una perspectiva del medio ambiente desde diversos enfoques. Asimismo, plantea un rol del maestro y del educando como agentes dinamizadores de la construcción del conocimiento y la modificación de conductas responsables con el medio ambiente.

The objective of this article is to formulate a pedagogical model for environmental education in response to the urgent need to create mechanisms and instruments that contribute to global sustainable development. To do so, the main theoretical aspects of education, pedagogy, pedagogical models and trends in environmental education are addressed. The Structural Cognitive Modifiability and Mediated Learning Experience Reueven Feuerstein theories have been analyzed and incorporated in the design. The design responds to the demands of modern society and to an environmental perspective from different approaches. Likewise, the role of teacher and the role of the learner as revitalizing agents of knowledge construction and modification of responsible behaviors with the environment are described.

La educacion amiiental (ea) como herramienta de la responsabilidad social (rs) / Environmental education (ee) as a tool for social responsibility (sr)

Las estrategias educativas actuales no muestran indicadores donde se destaque el papel de la Educación Ambiental (EA) en el enriquecimiento de valores para la convivencia colectiva, y en este aspecto, el cuidado de los recursos. Es aquí donde se hace necesario el enfoque prioritario de la materia en entidades destinadas a la educación, para la formación de individuos capaces de asumir, plantear, desarrollar y solventar la problemática ambiental y dar paso al desarrollo humano y al desarrollo sostenible. En materia de desarrollo y formación, los procesos de enseñanza - aprendizaje de la EA han sido abordados por la relevancia que representa pero no con la suficiente seriedad que ella merece. En el presente artículo se analiza la EA como proceso y herramienta de reproducción cultural y formación de ciudadanos críticos que contribuyan a la gestión de la Responsabilidad Social (RS). Para ello, se hace una recopilación de información académica y científica que permite profundizar en el propósito que se plantea, estableciéndose las relaciones que subyacen de cada uno de los contenidos epistémicos analizados.

The current educational strategies do not show indicators which highlight the role of environmental education (EE) in the enrichment of values for the collective coexistence, and in this respect, for the care of resources. This is where the subject priority approach becomes necessary in educational institutions for the education of individuals capable of assuming, proposing, developing and solving environmental problems and giving way to human development and sustainable development. As far as development and education, the EE teaching - learning processes have been addressed because of the relevance they have but not with the seriousness they deserve. This article analyzes EE as a process and a tool of cultural reproduction and education of critical citizens who contribute to the management of Social Responsibility (SR). To achiueve this goal, collection of scholarly and scientific information that allows deepening in the proposed purpose is carried out, establishing relationships that underlie each of the epistemic contents analyzed.

The nigrostriatal system in the presymptomatic and symptomatic stages in the MPTP monkey model: a PET, histological and biochemical study.

Parkinson's disease (PD) is diagnosed when striatal dopamine (DA) loss exceeds a certain threshold and the cardinal motor features become apparent. The presymptomatic compensatory mechanisms underlying the lack of motor manifestations despite progressive striatal depletion are not well understood. Most animal models of PD involve the induction of a severe dopaminergic deficit in an acute manner, which departs from the typical, chronic evolution of PD in humans. We have used 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administered to monkeys via a slow intoxication protocol to produce a more gradual development of nigral lesion. Twelve control and 38 MPTP-intoxicated monkeys were divided into four groups. The latter included monkeys who were always asymptomatic, monkeys who recovered after showing mild parkinsonian signs, and monkeys with stable, moderate and severe parkinsonism. We found a close correlation between cell loss in the substantia nigra pars compacta (SNc) and striatal dopaminergic depletion and the four motor states. There was an overall negative correlation between the degree of parkinsonism (Kurlan scale) and in vivo PET ((18)F-DOPA K(i) and (11)C-DTBZ binding potential), as well as with TH-immunoreactive cell counts in SNc, striatal dopaminergic markers (TH, DAT and VMAT2) and striatal DA concentration. This intoxication protocol permits to establish a critical threshold of SNc cell loss and dopaminergic innervation distinguishing between the asymptomatic and symptomatic parkinsonian stages. Compensatory changes in nigrostriatal dopaminergic activity occurred in the recovered and parkinsonian monkeys when DA depletion was at least 88% of control, and accordingly may be considered too late to explain compensatory mechanisms in the early asymptomatic period. Our findings suggest the need for further exploration of the role of non-striatal mechanisms in PD prior to the development of motor features.

Trigeminothalamic barrelette neurons: natural structural side asymmetries and sensory input-dependent plasticity in adult rats.

In the rodent trigeminal principal nucleus (Pr5) the barrelette thalamic-projecting neurons relay information from individual whiskers to corresponding contralateral thalamic barreloids. Here we investigated the presence of lateral asymmetries in the dendritic trees of these neurons, and the morphometric changes resulting from input-dependent plasticity in young adult rats. After retrograde labeling with dextran amines from the thalamus, neurons were digitally reconstructed with Neurolucida, and metrically and topologically analyzed with NeuroExplorer. The most unexpected and remarkable result was the observation of side-to-side asymmetries in the barrelette neurons of control rats. These asymmetries more significantly involved the number of low-grade trees and the total dendritic length, which were greater on the left side. Chronic global input loss resulting from infraorbital nerve (IoN) transection, or loss of active touch resulting from whisker clipping in the right neutralized, or even reversed, the observed lateral differences. While results after IoN transection have to be interpreted in the context of partial neuron death in this model, profound bilateral changes were found after haptic loss, which is achieved without inflicting any nerve damage. After whisker trimming, neurons on the left side closely resembled neurons on the right in controls, the natural dendritic length asymmetry being reversed mainly by a shortening of the left trees and a more moderate elongation of the right trees. These results demonstrate that dendritic morphometry is both side- and input-dependent, and that unilateral manipulation of the sensory periphery leads to bilateral morphometric changes in second order neurons of the whisker-barrel system. The presence of anatomical asymmetries in neural structures involved in early stages of somatosensory processing could help explain the expression of sensory input-dependent behavioral asymmetries.

When should re-consent of subjects participating in a clinical trial be requested? A case-oriented algorithm to assist in the decision-making process.

Investigators, sponsors, and institutional review boards have to decide when re-consent of clinical trials' participants must be obtained when new information becomes available. We present an algorithm to help in the decision-making process, which takes into consideration the kind of new information, the risk of exposure (patients could be on the treatment or in the follow-up phases), and the possibility of managing the case. Re-consent should be obtained in three of the eight possible situations.