Luis Pedro Morera - Academia.edu (original) (raw)

Papers by Luis Pedro Morera

Research paper thumbnail of Sensing light by horizontall cells in the chicken retina: a new player in the photoreceptive system

Investigative Ophthalmology & Visual Science, Jun 11, 2015

Research paper thumbnail of Felicidad laboral: Rol de la satisfacción con los recursos laborales, emociones, engagement y burnout

Revista Argentina de Ciencias del Comportamiento ( RACC ), 2018

Research paper thumbnail of Characterization of Chicken Retinal Horizontal Cell Primary Cultures

Investigative Ophthalmology & Visual Science, 2013

Research paper thumbnail of Reversal photoisomerization of all-trans retinal in primary cultures of chicken retinal ganglion cells

Investigative Ophthalmology & Visual Science, 2013

Research paper thumbnail of Medición del burnout: Estructura factorial, validez y confiabilidad en trabajadores argentinos

Interdisciplinaria: Revista de Psicología y Ciencias Afines, 2019

El burnout representa uno de los daños de carácter laboral y psicosocial más importantes en el mu... more El burnout representa uno de los daños de carácter laboral y psicosocial más importantes en el mundo actual. En el presente trabajo se analiza la estructura factorial, la validez y la confiabilidad de una medida de burnout en Argentina, compuesta por las escalas del Maslach Burnout Inventory-General survey (MBI-GS)y la subescala de despersonalzación correspondiente al Maslach Burnout Inventory-Human services. Se utilizó una muestra de 1903 trabajadores del sector público, privado y organizaciones sin fines de lucro. Para evaluar la estructura interna se pusieron a prueba un total de seis modelos. Los resultados obtenidos por medio de análisis factorial confirmatorio, indican que un modelo de dos factores correlacionados, compuesto por las dimensiones corazón del burnout (agotamiento y cinismo), es el que posee un mejor ajuste a los datos. Por su parte, los análisis de confiabilidad evidenciaron una consistencia interna aceptable, como así también una adecuada fiabilidad de constructo para los factores. Finalmente, se obtuvieron correlaciones significativas y en la dirección esperada entre los factores del burnout y medidas de engagement y afecto, proporcionando así evidencia externa de validez concurrente para los puntajes de la escala. Globalmente, los resultados son satisfactorios y avalan el uso del MBI-GS en el contexto argentino, aunque se requiere de nuevos estudios que examinen otras propiedades psicométricas relevantes. Se discuten las implicaciones de este trabajo para la evaluación y la investigación sobre burnout en Argentina.

Research paper thumbnail of Psychometric properties of the Recovery Experience Questionnaire at Argentine workers

Anales De Psicologia, 2020

espanolEl objetivo de este estudio consistio en examinar las propiedades psicometricas del “Cuest... more espanolEl objetivo de este estudio consistio en examinar las propiedades psicometricas del “Cuestionario de Experiencias de Recuperacion” para su uso en Argentina. La muestra estuvo compuesta por 505 trabajadores provenientes del sector publico, privado y organizaciones no gubernamentales. Los resultados del analisis factorial confirmatorio evidenciaron que un modelo de cuatro factores ─distanciamiento psicologico del trabajo, relajacion, busqueda de retos y control sobre el tiempo libre─ presento un buen ajuste a los datos. Por lo tanto, el cuestionario mantiene la misma estructura que la escala original. Los analisis de confiabilidad mostraron que la escala posee una adecuada consistencia interna (α = .75 - .92) y fiabilidad de constructo (H = .88 - .93). Se obtuvieron correlaciones teoricamente esperadas con medidas de burnout, work engagement y afecto negativo, aportando de esta manera evidencias externas de validez concurrente. En conclusion, la escala posee adecuadas propiedad...

Research paper thumbnail of Work engagement and burnout: real, redundant, or both? A further examination using a bifactor modelling approach

European Journal of Work and Organizational Psychology, 2020

Researchers have often debated whether burnout and work engagement are truly different concepts, ... more Researchers have often debated whether burnout and work engagement are truly different concepts, or whether they are opposite poles of the same construct and therfore redundant. Recent perspectives postulate that they are both real and redundant. In this paper we examine these three competing views using a bifactor modelling approach. A sample of 1787 Argentine employees completed the Utrecht Work Engagement Scale (UWES), the Maslach Burnout Inventory-General Survey (MBI-GS), and other work-related measures. Bifactor analysis showed that at the construct level, work engagement and burnout are not adequately represented by a single well-being dimension, indicating that they are distinct constructs. At the dimension level, vigour and exhaustion could not be accounted for by a general energy factor, meaning that these constructs are distinct rather than direct opposites of one energy continuum. In contrast, dedication and cynicism were substantially explained by a single identification factor, suggesting that they represent each other's opposite along an identification continuum. However, dedication and cynicism displayed a unique pattern of relationships with different external variables, implying that they are also real constructs. Collectively, the findings indicate that each of the competing views on the work engagement-burnout relationship has its merits. Implications for conceptualization and measurement are discussed.

Research paper thumbnail of Desarrollo y validación de una escala para medir satisfacción con los recursos laborales

Suma Psicológica, 2019

Resumen En los últimos 30 años la investigación empírica ha mostrado consistentemente la influenc... more Resumen En los últimos 30 años la investigación empírica ha mostrado consistentemente la influencia positiva de los recursos laborales en el bienestar y desempeño de los trabajadores. Sin embargo, se ha señalado que estos resultados positivos se asocian más con la satisfacción percibida que con los recursos provistos por la organización. En esta línea y tomando como referencia el modelo HERO se diseñó un instrumento para medir la satisfacción con los recursos laborales. Los análisis factoriales exploratorio y confirmatorio utilizando muestras de 492 y 508 trabajadores, respectivamente, respaldaron las cuatro dimensiones teóricas propuestas: satisfacción con los recursos de tarea, satisfacción con los recursos de equipo, satisfacción con los recursos de líder y satisfacción con los recursos de la organización. Se obtuvieron índices satisfactorios de consistencia interna y de fiabilidad del constructo, y evidencias de validez test-criterio con medidas de engagement y burnout. Se discute el valor práctico del nuevo instrumento y algunas sugerencias tendientes a examinar en mayor profundidad sus propiedades psicométricas.

Research paper thumbnail of Biomarcadores en la medición del estrés: una revisión sistemática

Ansiedad y Estrés, 2019

Resumen Introduccion y objetivos Existe un amplio consenso en la comunidad cientifica en relacion... more Resumen Introduccion y objetivos Existe un amplio consenso en la comunidad cientifica en relacion con la posibilidad de evaluar el estres a traves de marcadores biologicos asociados a los principales sistemas regulatorios de este proceso: el simpatico adrenomedular (SAM), el hipotalamico-hipofiso-adrenal (HHA) y el sistema inmunologico. Sin embargo, persisten interrogantes en relacion con el uso de biomarcadores: a) ?Cuales son los biomarcadores de estres mas utilizados? b) ?Que tecnicas son recomendables para la determinacion de los mismos? c) ?A partir de que muestras biologicas es aconsejable cuantificarlos? El presente articulo tiene como objetivo efectuar una revision sistematica de la literatura especializada con el fin de analizar dichos interrogantes. Materiales y metodos Se efectuo una revision sistematica en diferentes bases de datos (Pubmed, PMC y MEDLINE), considerando articulos de los ultimos 10 anos. Se identificaron 710 estudios que fueron sometidos al proceso de seleccion, 33 de los cuales se incluyeron finalmente en la revision. Resultados y conclusiones Se han publicado numerosas revisiones que buscan establecer un vinculo entre biomarcadores y diferentes problemas asociados al estres. Si bien los resultados son prometedores, el campo se enfrenta con importantes desafios, como, por ejemplo, encontrar consenso en la definicion de las mejores practicas para el uso de biomarcadores. A partir de la presente revision podemos concluir que los biomarcadores predominantemente utilizados para determinar la activacion del eje SAM son el ritmo cardiaco y la presion sanguinea; en cuanto al eje HHA, el cortisol ha sido el marcador biologico mas comunmente medido tanto en sangre como en saliva y en cabello. Finalmente, en lo referente a marcadores representativos de la activacion del sistema inmune debido a estres, la IL-6 y la PCR fueron las mas frecuentemente analizadas.

Research paper thumbnail of The Visual Cycle in the Inner Retina of Chicken and the Involvement of Retinal G-Protein-Coupled Receptor (RGR)

Molecular neurobiology, May 17, 2016

The vertebrate retina contains typical photoreceptor (PR) cones and rods responsible for day/nigh... more The vertebrate retina contains typical photoreceptor (PR) cones and rods responsible for day/night vision, respectively, and intrinsically photosensitive retinal ganglion cells (ipRGCs) involved in the regulation of non-image-forming tasks. Rhodopsin/cone opsin photopigments in visual PRs or melanopsin (Opn4) in ipRGCs utilizes retinaldehyde as a chromophore. The retinoid regeneration process denominated as "visual cycle" involves the retinal pigment epithelium (RPE) or Müller glial cells. Opn4, on the contrary, has been characterized as a bi/tristable photopigment, in which a photon of one wavelength isomerizes 11-cis to all-trans retinal (Ral), with a second photon re-isomerizing it back. However, it is unknown how the chromophore is further metabolized in the inner retina. Nor is it yet clear whether an alternative secondary cycle occurs involving players such as the retinal G-protein-coupled receptor (RGR), a putative photoisomerase of unidentified inner retinal activi...

Research paper thumbnail of Work-Related Mental Health Issues in Graduate Student Population

Frontiers in Neuroscience, 2021

The scientific and educational community is becoming increasingly aware of the impact of current ... more The scientific and educational community is becoming increasingly aware of the impact of current academic working conditions on graduate students’ mental health and how this is affecting scientific progress and ultimately society as a whole. Our study aimed to shed light on the work-related mental health issues affecting graduate students, providing a comprehensive research work including psychological and biological assessment. Our findings showed that a sizeable number of graduate student present anxiety, depression, or high burnout and that the time spent in academia plays an important role. The graduate student population displayed a specific work-related mental health issues profile with an altered hypothalamic–pituitary–adrenal (HPA) axis and low levels of work engagement. Finally, graduate students were equally stressed, with less work engagement, and more anxious and depressed than general workers.

Research paper thumbnail of Estudios sobre la Expresión y Función de Fotopigmentos No-Visuales de la Familia de Melanopsinas en la Retina Interna de Vertebrados

Research paper thumbnail of In Vitro Evaluation of Monohalogenated Semicarbazones and Thiosemicarbazones as Potential Cytotoxic Agents Induction of Apoptosis and Genotoxicity

A series of halogenated Semicarbazones (SCs) and Thiosemicarbazones (TSCs) (11-30) were synthesiz... more A series of halogenated Semicarbazones (SCs) and Thiosemicarbazones (TSCs) (11-30) were synthesized from mono fluorinated-, bromine- and chlorinated acetophenones (1-10). Structures were confirmed by Nuclear Magnetic Resonance (NMR) spectral data. Both effects, the halogenated substituent and the position of the substitution on the antiproliferative activity, were systematically investigated for the first time. Cytotoxic activity was evaluated, using tetrazolium salt method (MTT), in two murine cell lines: CT26 (colon cancer) and B16 (melanoma). Only, o-, m- and p-fluorinated SCs and TSCs showed significant cytotoxic activity. Among them, compounds with fluorine at m-position in the phenyl ring showed the superior antiproliferative activity. The most actives derivatives were: m-Fluoroacetophenone semicarbazone (13) (μM; IC50 =7.2 ± 0.5, IC50=8.1 ± 0.2) and m-Fluoroacetophenone Thiosemicarbazone (23) (μM; IC50 = 3.1 ± 0.4, IC50=4.9 ± 0.5) in CT26 and B16, respectively. In addition, s...

Research paper thumbnail of Non-visual Opsins and Novel Photo-Detectors in the Vertebrate Inner Retina Mediate Light Responses Within the Blue Spectrum Region

Cellular and Molecular Neurobiology, 2020

In recent decades, a number of novel non-visual opsin photopigments belonging to the family of G ... more In recent decades, a number of novel non-visual opsin photopigments belonging to the family of G protein- coupled receptors, likely involved in a number of non-image-forming processes, have been identified and characterized in cells of the inner retina of vertebrates. It is now known that the vertebrate retina is composed of visual photoreceptor cones and rods responsible for diurnal/color and nocturnal/black and white vision, and cells like the intrinsically photosensitive retinal ganglion cells (ipRGCs) and photosensitive horizontal cells in the inner retina, both detecting blue light and expressing the photopigment melanopsin (Opn4). Remarkably, these non-visual photopigments can continue to operate even in the absence of vision under retinal degeneration. Moreover, inner retinal neurons and Müller glial cells have been shown to express other photopigments such as the photoisomerase retinal G protein-coupled receptor (RGR), encephalopsin (Opn3), and neuropsin (Opn5), all able to detect blue/violet light and implicated in chromophore recycling, retinal clock synchronization, neuron-to-glia communication, and other activities. The discovery of these new photopigments in the inner retina of vertebrates is strong evidence of novel light-regulated activities. This review focuses on the features, localization, photocascade, and putative functions of these novel non-visual opsins in an attempt to shed light on their role in the inner retina of vertebrates and in the physiology of the whole organism.

Research paper thumbnail of Horizontal cells expressing melanopsin x are novel photoreceptors in the avian inner retina

Proceedings of the National Academy of Sciences of the United States of America, Nov 15, 2016

In the vertebrate retina, three types of photoreceptors-visual photoreceptor cones and rods and t... more In the vertebrate retina, three types of photoreceptors-visual photoreceptor cones and rods and the intrinsically photosensitive retinal ganglion cells (ipRGCs)-converged through evolution to detect light and regulate image- and nonimage-forming activities such as photic entrainment of circadian rhythms, pupillary light reflexes, etc. ipRGCs express the nonvisual photopigment melanopsin (OPN4), encoded by two genes: the Xenopus (Opn4x) and mammalian (Opn4m) orthologs. In the chicken retina, both OPN4 proteins are found in ipRGCs, and Opn4x is also present in retinal horizontal cells (HCs), which connect with visual photoreceptors. Here we investigate the intrinsic photosensitivity and functioning of HCs from primary cultures of embryonic retinas at day 15 by using calcium fluorescent fluo4 imaging, pharmacological inhibitory treatments, and Opn4x knockdown. Results show that HCs are avian photoreceptors with a retinal-based OPN4X photopigment conferring intrinsic photosensitivity. L...

Research paper thumbnail of Melanopsin and the Non-visual Photochemistry in the Inner Retina of Vertebrates(†)

Photochemistry and photobiology, Jan 23, 2015

Melanopsin (Opn4), a member of the G protein-coupled receptor family, is a vitamin A-based opsin ... more Melanopsin (Opn4), a member of the G protein-coupled receptor family, is a vitamin A-based opsin in the vertebrate retina that has been shown to be involved in the synchronization of circadian rhythms, pupillary light reflexes, melatonin suppression and other light-regulated tasks. In non-mammalian vertebrates there are two Opn4 genes, Opn4m and Opn4x, the mammalian and Xenopus orthologs, respectively. Opn4x is only expressed in non-mammalian vertebrates including reptiles, fish and birds, while Opn4m is found in a subset of retinal ganglion cells (RGCs), the intrinsically photosensitive (ip) RGCs of the inner retina of both mammals and non-mammalian vertebrates. All opsins described utilize retinaldehyde as chromophore, photoisomerized from 11-cis- to all-trans-retinal upon light exposure. Visual retinal photoreceptor cones and rods, responsible for day and night vision respectively, recycle retinoids through a process called the visual cycle that involves the retinal pigment epith...

Research paper thumbnail of Early Appearance of Nonvisual and Circadian Markers in the Developing Inner Retinal Cells of Chicken

BioMed Research International, 2014

The retina is a key component of the vertebrate circadian system; it is responsible for detecting... more The retina is a key component of the vertebrate circadian system; it is responsible for detecting and transmitting the environmental illumination conditions (day/night cycles) to the brain that synchronize the circadian clock located in the suprachiasmatic nucleus (SCN). For this, retinal ganglion cells (RGCs) project to the SCN and other nonvisual areas. In the chicken, intrinsically photosensitive RGCs (ipRGCs) expressing the photopigment melanopsin (Opn4) transmit photic information and regulate diverse nonvisual tasks. In nonmammalian vertebrates, two genes encodeOpn4: theXenopus(Opn4x) and the mammalian (Opn4m) orthologs. RGCs express bothOpn4genes but are not the only inner retinal cells expressingOpn4x: horizontal cells (HCs) also do so. Here, we further characterize primary cultures of both populations of inner retinal cells (RGCs and HCs) expressingOpn4x. The expression of this nonvisual photopigment, as well as that for different circadian markers such as the clock genesBm...

Research paper thumbnail of A novel method to prepare highly enriched primary cultures of chicken retinal horizontal cells

Experimental Eye Research, 2012

Research paper thumbnail of From Work Well-Being to Burnout: A Hypothetical Phase Model

Frontiers in Neuroscience, 2020

Upon exposure to chronic stressors, how do individuals move from being in a healthy state to a bu... more Upon exposure to chronic stressors, how do individuals move from being in a healthy state to a burnout? Strikingly in literature, this has prevailed a categorical view rather than a dimensional one, thus the underlying process that explains the transition from one state to another remains unclear. The aims of the present study are (a) to examine intermediate states between work engagement and burnout using cluster analysis and (b) to examine cortisol differences across these states. Two-hundred and eighty-one Argentine workers completed self-report measures of work engagement and burnout. Salivary cortisol was measured at three time-points: immediately after awakening and 30 and 40min thereafter. Results showed four different states based on the scores in cynicism, exhaustion, vigor, and dedication: engaged, strained, cynical, and burned-out. Cortisol levels were found to be moderate in the engaged state, increased in the strained and cynical states, and decreased in the burned-out state. The increase/decrease in cortisol across the four stages reconciles apparent contradictory findings regarding hypercortisolism and hypocortisolism, and suggests that they may represent different phases in the transition from engagement to burnout. A phase model from engagement to burnout is proposed and future research aimed at evaluating this model is suggested.

Research paper thumbnail of From Work Well-Being to Burnout: A Hypothetical Phase Model

Frontiers in Neuroscience, 2020

Upon exposure to chronic stressors, how do individuals move from being in a healthy state to a bu... more Upon exposure to chronic stressors, how do individuals move from being in a healthy state to a burnout? Strikingly in literature, this has prevailed a categorical view rather than a dimensional one, thus the underlying process that explains the transition from one state to another remains unclear. The aims of the present study are (a) to examine intermediate states between work engagement and burnout using cluster analysis and (b) to examine cortisol differences across these states. Two-hundred and eighty-one Argentine workers completed self-report measures of work engagement and burnout. Salivary cortisol was measured at three time-points: immediately after awakening and 30 and 40min thereafter. Results showed four different states based on the scores in cynicism, exhaustion, vigor, and dedication: engaged, strained, cynical, and burned-out. Cortisol levels were found to be moderate in the engaged state, increased in the strained and cynical states, and decreased in the burned-out state. The increase/decrease in cortisol across the four stages reconciles apparent contradictory findings regarding hypercortisolism and hypocortisolism, and suggests that they may represent different phases in the transition from engagement to burnout. A phase model from engagement to burnout is proposed and future research aimed at evaluating this model is suggested.

Research paper thumbnail of Sensing light by horizontall cells in the chicken retina: a new player in the photoreceptive system

Investigative Ophthalmology & Visual Science, Jun 11, 2015

Research paper thumbnail of Felicidad laboral: Rol de la satisfacción con los recursos laborales, emociones, engagement y burnout

Revista Argentina de Ciencias del Comportamiento ( RACC ), 2018

Research paper thumbnail of Characterization of Chicken Retinal Horizontal Cell Primary Cultures

Investigative Ophthalmology & Visual Science, 2013

Research paper thumbnail of Reversal photoisomerization of all-trans retinal in primary cultures of chicken retinal ganglion cells

Investigative Ophthalmology & Visual Science, 2013

Research paper thumbnail of Medición del burnout: Estructura factorial, validez y confiabilidad en trabajadores argentinos

Interdisciplinaria: Revista de Psicología y Ciencias Afines, 2019

El burnout representa uno de los daños de carácter laboral y psicosocial más importantes en el mu... more El burnout representa uno de los daños de carácter laboral y psicosocial más importantes en el mundo actual. En el presente trabajo se analiza la estructura factorial, la validez y la confiabilidad de una medida de burnout en Argentina, compuesta por las escalas del Maslach Burnout Inventory-General survey (MBI-GS)y la subescala de despersonalzación correspondiente al Maslach Burnout Inventory-Human services. Se utilizó una muestra de 1903 trabajadores del sector público, privado y organizaciones sin fines de lucro. Para evaluar la estructura interna se pusieron a prueba un total de seis modelos. Los resultados obtenidos por medio de análisis factorial confirmatorio, indican que un modelo de dos factores correlacionados, compuesto por las dimensiones corazón del burnout (agotamiento y cinismo), es el que posee un mejor ajuste a los datos. Por su parte, los análisis de confiabilidad evidenciaron una consistencia interna aceptable, como así también una adecuada fiabilidad de constructo para los factores. Finalmente, se obtuvieron correlaciones significativas y en la dirección esperada entre los factores del burnout y medidas de engagement y afecto, proporcionando así evidencia externa de validez concurrente para los puntajes de la escala. Globalmente, los resultados son satisfactorios y avalan el uso del MBI-GS en el contexto argentino, aunque se requiere de nuevos estudios que examinen otras propiedades psicométricas relevantes. Se discuten las implicaciones de este trabajo para la evaluación y la investigación sobre burnout en Argentina.

Research paper thumbnail of Psychometric properties of the Recovery Experience Questionnaire at Argentine workers

Anales De Psicologia, 2020

espanolEl objetivo de este estudio consistio en examinar las propiedades psicometricas del “Cuest... more espanolEl objetivo de este estudio consistio en examinar las propiedades psicometricas del “Cuestionario de Experiencias de Recuperacion” para su uso en Argentina. La muestra estuvo compuesta por 505 trabajadores provenientes del sector publico, privado y organizaciones no gubernamentales. Los resultados del analisis factorial confirmatorio evidenciaron que un modelo de cuatro factores ─distanciamiento psicologico del trabajo, relajacion, busqueda de retos y control sobre el tiempo libre─ presento un buen ajuste a los datos. Por lo tanto, el cuestionario mantiene la misma estructura que la escala original. Los analisis de confiabilidad mostraron que la escala posee una adecuada consistencia interna (α = .75 - .92) y fiabilidad de constructo (H = .88 - .93). Se obtuvieron correlaciones teoricamente esperadas con medidas de burnout, work engagement y afecto negativo, aportando de esta manera evidencias externas de validez concurrente. En conclusion, la escala posee adecuadas propiedad...

Research paper thumbnail of Work engagement and burnout: real, redundant, or both? A further examination using a bifactor modelling approach

European Journal of Work and Organizational Psychology, 2020

Researchers have often debated whether burnout and work engagement are truly different concepts, ... more Researchers have often debated whether burnout and work engagement are truly different concepts, or whether they are opposite poles of the same construct and therfore redundant. Recent perspectives postulate that they are both real and redundant. In this paper we examine these three competing views using a bifactor modelling approach. A sample of 1787 Argentine employees completed the Utrecht Work Engagement Scale (UWES), the Maslach Burnout Inventory-General Survey (MBI-GS), and other work-related measures. Bifactor analysis showed that at the construct level, work engagement and burnout are not adequately represented by a single well-being dimension, indicating that they are distinct constructs. At the dimension level, vigour and exhaustion could not be accounted for by a general energy factor, meaning that these constructs are distinct rather than direct opposites of one energy continuum. In contrast, dedication and cynicism were substantially explained by a single identification factor, suggesting that they represent each other's opposite along an identification continuum. However, dedication and cynicism displayed a unique pattern of relationships with different external variables, implying that they are also real constructs. Collectively, the findings indicate that each of the competing views on the work engagement-burnout relationship has its merits. Implications for conceptualization and measurement are discussed.

Research paper thumbnail of Desarrollo y validación de una escala para medir satisfacción con los recursos laborales

Suma Psicológica, 2019

Resumen En los últimos 30 años la investigación empírica ha mostrado consistentemente la influenc... more Resumen En los últimos 30 años la investigación empírica ha mostrado consistentemente la influencia positiva de los recursos laborales en el bienestar y desempeño de los trabajadores. Sin embargo, se ha señalado que estos resultados positivos se asocian más con la satisfacción percibida que con los recursos provistos por la organización. En esta línea y tomando como referencia el modelo HERO se diseñó un instrumento para medir la satisfacción con los recursos laborales. Los análisis factoriales exploratorio y confirmatorio utilizando muestras de 492 y 508 trabajadores, respectivamente, respaldaron las cuatro dimensiones teóricas propuestas: satisfacción con los recursos de tarea, satisfacción con los recursos de equipo, satisfacción con los recursos de líder y satisfacción con los recursos de la organización. Se obtuvieron índices satisfactorios de consistencia interna y de fiabilidad del constructo, y evidencias de validez test-criterio con medidas de engagement y burnout. Se discute el valor práctico del nuevo instrumento y algunas sugerencias tendientes a examinar en mayor profundidad sus propiedades psicométricas.

Research paper thumbnail of Biomarcadores en la medición del estrés: una revisión sistemática

Ansiedad y Estrés, 2019

Resumen Introduccion y objetivos Existe un amplio consenso en la comunidad cientifica en relacion... more Resumen Introduccion y objetivos Existe un amplio consenso en la comunidad cientifica en relacion con la posibilidad de evaluar el estres a traves de marcadores biologicos asociados a los principales sistemas regulatorios de este proceso: el simpatico adrenomedular (SAM), el hipotalamico-hipofiso-adrenal (HHA) y el sistema inmunologico. Sin embargo, persisten interrogantes en relacion con el uso de biomarcadores: a) ?Cuales son los biomarcadores de estres mas utilizados? b) ?Que tecnicas son recomendables para la determinacion de los mismos? c) ?A partir de que muestras biologicas es aconsejable cuantificarlos? El presente articulo tiene como objetivo efectuar una revision sistematica de la literatura especializada con el fin de analizar dichos interrogantes. Materiales y metodos Se efectuo una revision sistematica en diferentes bases de datos (Pubmed, PMC y MEDLINE), considerando articulos de los ultimos 10 anos. Se identificaron 710 estudios que fueron sometidos al proceso de seleccion, 33 de los cuales se incluyeron finalmente en la revision. Resultados y conclusiones Se han publicado numerosas revisiones que buscan establecer un vinculo entre biomarcadores y diferentes problemas asociados al estres. Si bien los resultados son prometedores, el campo se enfrenta con importantes desafios, como, por ejemplo, encontrar consenso en la definicion de las mejores practicas para el uso de biomarcadores. A partir de la presente revision podemos concluir que los biomarcadores predominantemente utilizados para determinar la activacion del eje SAM son el ritmo cardiaco y la presion sanguinea; en cuanto al eje HHA, el cortisol ha sido el marcador biologico mas comunmente medido tanto en sangre como en saliva y en cabello. Finalmente, en lo referente a marcadores representativos de la activacion del sistema inmune debido a estres, la IL-6 y la PCR fueron las mas frecuentemente analizadas.

Research paper thumbnail of The Visual Cycle in the Inner Retina of Chicken and the Involvement of Retinal G-Protein-Coupled Receptor (RGR)

Molecular neurobiology, May 17, 2016

The vertebrate retina contains typical photoreceptor (PR) cones and rods responsible for day/nigh... more The vertebrate retina contains typical photoreceptor (PR) cones and rods responsible for day/night vision, respectively, and intrinsically photosensitive retinal ganglion cells (ipRGCs) involved in the regulation of non-image-forming tasks. Rhodopsin/cone opsin photopigments in visual PRs or melanopsin (Opn4) in ipRGCs utilizes retinaldehyde as a chromophore. The retinoid regeneration process denominated as "visual cycle" involves the retinal pigment epithelium (RPE) or Müller glial cells. Opn4, on the contrary, has been characterized as a bi/tristable photopigment, in which a photon of one wavelength isomerizes 11-cis to all-trans retinal (Ral), with a second photon re-isomerizing it back. However, it is unknown how the chromophore is further metabolized in the inner retina. Nor is it yet clear whether an alternative secondary cycle occurs involving players such as the retinal G-protein-coupled receptor (RGR), a putative photoisomerase of unidentified inner retinal activi...

Research paper thumbnail of Work-Related Mental Health Issues in Graduate Student Population

Frontiers in Neuroscience, 2021

The scientific and educational community is becoming increasingly aware of the impact of current ... more The scientific and educational community is becoming increasingly aware of the impact of current academic working conditions on graduate students’ mental health and how this is affecting scientific progress and ultimately society as a whole. Our study aimed to shed light on the work-related mental health issues affecting graduate students, providing a comprehensive research work including psychological and biological assessment. Our findings showed that a sizeable number of graduate student present anxiety, depression, or high burnout and that the time spent in academia plays an important role. The graduate student population displayed a specific work-related mental health issues profile with an altered hypothalamic–pituitary–adrenal (HPA) axis and low levels of work engagement. Finally, graduate students were equally stressed, with less work engagement, and more anxious and depressed than general workers.

Research paper thumbnail of Estudios sobre la Expresión y Función de Fotopigmentos No-Visuales de la Familia de Melanopsinas en la Retina Interna de Vertebrados

Research paper thumbnail of In Vitro Evaluation of Monohalogenated Semicarbazones and Thiosemicarbazones as Potential Cytotoxic Agents Induction of Apoptosis and Genotoxicity

A series of halogenated Semicarbazones (SCs) and Thiosemicarbazones (TSCs) (11-30) were synthesiz... more A series of halogenated Semicarbazones (SCs) and Thiosemicarbazones (TSCs) (11-30) were synthesized from mono fluorinated-, bromine- and chlorinated acetophenones (1-10). Structures were confirmed by Nuclear Magnetic Resonance (NMR) spectral data. Both effects, the halogenated substituent and the position of the substitution on the antiproliferative activity, were systematically investigated for the first time. Cytotoxic activity was evaluated, using tetrazolium salt method (MTT), in two murine cell lines: CT26 (colon cancer) and B16 (melanoma). Only, o-, m- and p-fluorinated SCs and TSCs showed significant cytotoxic activity. Among them, compounds with fluorine at m-position in the phenyl ring showed the superior antiproliferative activity. The most actives derivatives were: m-Fluoroacetophenone semicarbazone (13) (μM; IC50 =7.2 ± 0.5, IC50=8.1 ± 0.2) and m-Fluoroacetophenone Thiosemicarbazone (23) (μM; IC50 = 3.1 ± 0.4, IC50=4.9 ± 0.5) in CT26 and B16, respectively. In addition, s...

Research paper thumbnail of Non-visual Opsins and Novel Photo-Detectors in the Vertebrate Inner Retina Mediate Light Responses Within the Blue Spectrum Region

Cellular and Molecular Neurobiology, 2020

In recent decades, a number of novel non-visual opsin photopigments belonging to the family of G ... more In recent decades, a number of novel non-visual opsin photopigments belonging to the family of G protein- coupled receptors, likely involved in a number of non-image-forming processes, have been identified and characterized in cells of the inner retina of vertebrates. It is now known that the vertebrate retina is composed of visual photoreceptor cones and rods responsible for diurnal/color and nocturnal/black and white vision, and cells like the intrinsically photosensitive retinal ganglion cells (ipRGCs) and photosensitive horizontal cells in the inner retina, both detecting blue light and expressing the photopigment melanopsin (Opn4). Remarkably, these non-visual photopigments can continue to operate even in the absence of vision under retinal degeneration. Moreover, inner retinal neurons and Müller glial cells have been shown to express other photopigments such as the photoisomerase retinal G protein-coupled receptor (RGR), encephalopsin (Opn3), and neuropsin (Opn5), all able to detect blue/violet light and implicated in chromophore recycling, retinal clock synchronization, neuron-to-glia communication, and other activities. The discovery of these new photopigments in the inner retina of vertebrates is strong evidence of novel light-regulated activities. This review focuses on the features, localization, photocascade, and putative functions of these novel non-visual opsins in an attempt to shed light on their role in the inner retina of vertebrates and in the physiology of the whole organism.

Research paper thumbnail of Horizontal cells expressing melanopsin x are novel photoreceptors in the avian inner retina

Proceedings of the National Academy of Sciences of the United States of America, Nov 15, 2016

In the vertebrate retina, three types of photoreceptors-visual photoreceptor cones and rods and t... more In the vertebrate retina, three types of photoreceptors-visual photoreceptor cones and rods and the intrinsically photosensitive retinal ganglion cells (ipRGCs)-converged through evolution to detect light and regulate image- and nonimage-forming activities such as photic entrainment of circadian rhythms, pupillary light reflexes, etc. ipRGCs express the nonvisual photopigment melanopsin (OPN4), encoded by two genes: the Xenopus (Opn4x) and mammalian (Opn4m) orthologs. In the chicken retina, both OPN4 proteins are found in ipRGCs, and Opn4x is also present in retinal horizontal cells (HCs), which connect with visual photoreceptors. Here we investigate the intrinsic photosensitivity and functioning of HCs from primary cultures of embryonic retinas at day 15 by using calcium fluorescent fluo4 imaging, pharmacological inhibitory treatments, and Opn4x knockdown. Results show that HCs are avian photoreceptors with a retinal-based OPN4X photopigment conferring intrinsic photosensitivity. L...

Research paper thumbnail of Melanopsin and the Non-visual Photochemistry in the Inner Retina of Vertebrates(†)

Photochemistry and photobiology, Jan 23, 2015

Melanopsin (Opn4), a member of the G protein-coupled receptor family, is a vitamin A-based opsin ... more Melanopsin (Opn4), a member of the G protein-coupled receptor family, is a vitamin A-based opsin in the vertebrate retina that has been shown to be involved in the synchronization of circadian rhythms, pupillary light reflexes, melatonin suppression and other light-regulated tasks. In non-mammalian vertebrates there are two Opn4 genes, Opn4m and Opn4x, the mammalian and Xenopus orthologs, respectively. Opn4x is only expressed in non-mammalian vertebrates including reptiles, fish and birds, while Opn4m is found in a subset of retinal ganglion cells (RGCs), the intrinsically photosensitive (ip) RGCs of the inner retina of both mammals and non-mammalian vertebrates. All opsins described utilize retinaldehyde as chromophore, photoisomerized from 11-cis- to all-trans-retinal upon light exposure. Visual retinal photoreceptor cones and rods, responsible for day and night vision respectively, recycle retinoids through a process called the visual cycle that involves the retinal pigment epith...

Research paper thumbnail of Early Appearance of Nonvisual and Circadian Markers in the Developing Inner Retinal Cells of Chicken

BioMed Research International, 2014

The retina is a key component of the vertebrate circadian system; it is responsible for detecting... more The retina is a key component of the vertebrate circadian system; it is responsible for detecting and transmitting the environmental illumination conditions (day/night cycles) to the brain that synchronize the circadian clock located in the suprachiasmatic nucleus (SCN). For this, retinal ganglion cells (RGCs) project to the SCN and other nonvisual areas. In the chicken, intrinsically photosensitive RGCs (ipRGCs) expressing the photopigment melanopsin (Opn4) transmit photic information and regulate diverse nonvisual tasks. In nonmammalian vertebrates, two genes encodeOpn4: theXenopus(Opn4x) and the mammalian (Opn4m) orthologs. RGCs express bothOpn4genes but are not the only inner retinal cells expressingOpn4x: horizontal cells (HCs) also do so. Here, we further characterize primary cultures of both populations of inner retinal cells (RGCs and HCs) expressingOpn4x. The expression of this nonvisual photopigment, as well as that for different circadian markers such as the clock genesBm...

Research paper thumbnail of A novel method to prepare highly enriched primary cultures of chicken retinal horizontal cells

Experimental Eye Research, 2012

Research paper thumbnail of From Work Well-Being to Burnout: A Hypothetical Phase Model

Frontiers in Neuroscience, 2020

Upon exposure to chronic stressors, how do individuals move from being in a healthy state to a bu... more Upon exposure to chronic stressors, how do individuals move from being in a healthy state to a burnout? Strikingly in literature, this has prevailed a categorical view rather than a dimensional one, thus the underlying process that explains the transition from one state to another remains unclear. The aims of the present study are (a) to examine intermediate states between work engagement and burnout using cluster analysis and (b) to examine cortisol differences across these states. Two-hundred and eighty-one Argentine workers completed self-report measures of work engagement and burnout. Salivary cortisol was measured at three time-points: immediately after awakening and 30 and 40min thereafter. Results showed four different states based on the scores in cynicism, exhaustion, vigor, and dedication: engaged, strained, cynical, and burned-out. Cortisol levels were found to be moderate in the engaged state, increased in the strained and cynical states, and decreased in the burned-out state. The increase/decrease in cortisol across the four stages reconciles apparent contradictory findings regarding hypercortisolism and hypocortisolism, and suggests that they may represent different phases in the transition from engagement to burnout. A phase model from engagement to burnout is proposed and future research aimed at evaluating this model is suggested.

Research paper thumbnail of From Work Well-Being to Burnout: A Hypothetical Phase Model

Frontiers in Neuroscience, 2020

Upon exposure to chronic stressors, how do individuals move from being in a healthy state to a bu... more Upon exposure to chronic stressors, how do individuals move from being in a healthy state to a burnout? Strikingly in literature, this has prevailed a categorical view rather than a dimensional one, thus the underlying process that explains the transition from one state to another remains unclear. The aims of the present study are (a) to examine intermediate states between work engagement and burnout using cluster analysis and (b) to examine cortisol differences across these states. Two-hundred and eighty-one Argentine workers completed self-report measures of work engagement and burnout. Salivary cortisol was measured at three time-points: immediately after awakening and 30 and 40min thereafter. Results showed four different states based on the scores in cynicism, exhaustion, vigor, and dedication: engaged, strained, cynical, and burned-out. Cortisol levels were found to be moderate in the engaged state, increased in the strained and cynical states, and decreased in the burned-out state. The increase/decrease in cortisol across the four stages reconciles apparent contradictory findings regarding hypercortisolism and hypocortisolism, and suggests that they may represent different phases in the transition from engagement to burnout. A phase model from engagement to burnout is proposed and future research aimed at evaluating this model is suggested.