Ozone pollution, oxidative stress, synaptic plasticity, and neurodegeneration.

INTRODUCTION: Overpopulation and industrial growth result in an increase in air pollution, mainly due to suspended particulate matter and the formation of ozone. Repeated exposure to low doses of ozone, such as on a day with high air pollution levels, results in a state of chronic oxidative stress, causing the loss of dendritic spines, alterations in cerebral plasticity and in learning and memory mechanisms, and neuronal death and a loss of brain repair capacity. This has a direct impact on human health, increasing the incidence of chronic and degenerative diseases. DEVELOPMENT: We performed a search of the PubMed, Scopus, and Google Scholar databases for original articles and reviews published between 2000 and 2018 and addressing the main consequences of ozone exposure on synaptic plasticity, information processing in cognitive processes, and the alterations that may lead to the development of neurodegenerative diseases. CONCLUSIONS: This review describes one of the pathophysiological mechanisms of the effect of repeated exposure to low doses of ozone, which causes loss of synaptic plasticity by producing a state of chronic oxidative stress. This brain function is key to both information processing and the generation of structural changes in neuronal populations. We also address the effect of chronic ozone exposure on brain tissue and the close relationship between ozone pollution and the appearance and progression of neurodegenerative diseases.

Effect of exposure to low doses of ozone on interleukin 17A expression during progressive neurodegeneration in the rat hippocampus.

INTRODUCTION: Chronic exposure to low doses of ozone causes oxidative stress and loss of regulation of the inflammatory response, leading to progressive neurodegeneration. OBJECTIVE: We studied the effect of chronic exposure to low doses of ozone on IL-17A concentration and expression in neurons, microglia, astrocytes, and T cells in the rat hippocampus. METHODS: We used 72 Wistar rats, divided into 6 groups (n=12): a control group (no ozone exposure) and 5 groups exposed to ozone (0.25ppm, 4h daily) for 7, 15, 30, 60, and 90 days. We processed 6 rats from each group to quantify IL-17A by ELISA; the remaining 6 were processed for immunohistochemistry (against IL-17A and GFAP, Iba1, NeuN, and CD3). RESULTS: The ELISA study data showed a significant increase in IL-17A concentrations in the 7-, 15-, 30-, and 60-day exposure groups, with regard to the control group (P<.05). Furthermore, they indicate that hippocampal neurons were the cells showing greatest immunoreactivity against IL-17A between 60 and 90 days of exposure to ozone; we also observed an increase in activated astrocytes in the 30- and 60-day exposure groups. CONCLUSION: Exposure to ozone in rats induces an increase in IL-17A expression, mainly in hippocampal neurons, accompanied by hippocampal astrocyte activation during chronic neurodegeneration, similar to that observed in Alzheimer disease in humans.

Consideraciones éticas en la práctica médica

Resumen Actualmente la práctica clínica se ve enfrentada a una gran presión en los servicios clínicos públicos, privados, investigación, etc. El avance en ciencia y tecnología, asociado a gran publicidad por diversas redes, habitualmente no científicas, somete al cuerpo médico a una serie de dilemas éticos en forma diaria. Recursos limitados en el servicio público y una población que exige solución a sus problemas de salud, nos hace reflexionar sobre cómo tomar las decisiones más adecuadas, acudiendo a los principios éticos, cultivando valores personales, solicitando consentimiento informado, etc. Este texto pretende poner en contexto los temas de ética clínica con los que nos enfrentamos a diario.

Abstract Clinical practice is currently facing a great pressure on the public and private clinical services, research, etc. The progress in science and technology, associated with great publicity through various networks, usually unscientific, subjects the medical staff to a number of ethical dilemmas on a daily basis. Limited resources in the public service and a population that demands solutions to its health problems, makes us reflect on how to make the most appropriate decisions, turning to ethicalprinciples, cultivating personal values, requesting informed consent, etc. This text aims to put into context the clinical ethics issues that we face on a daily basis.

[Diagnosis of laryngopharyngeal Reflux by Impedance with esophageal pHmetry in children with chronic dysphonia]. / Diagnóstico de Reflujo faringolaríngeo mediante Impedanciometría con pHmetría esofágica en niños con disfonía crónica.

INTRODUCTION: Laryngopharyngeal Reflux (LPR) is the retrograde flow of gastric or duodenal contents into the pharynx and larynx, causing inflammation in the upper aerodigestive tract. Traditionally, a pH monitoring study with an acid reflux index was used. The use of multichannel intraluminal impedance testing with pH monitoring (MII-pH) confirms a causal relationship between suspicious symptoms and LPR. OBJECTIVES: To evaluate LPR diagnosed by MII-pH in the pediatric population consulting due to chronic dysphonia and laryngoscopic findings suggestive of LPR, in addition, to measure the concordance between MII-pH and traditional pH monitoring. PATIENTS AND METHOD: Descriptive, prospective study of patients consulting at the Gastroenterology or Otorhinolaryngology polyclinic due to chronic dysphonia, whose nasofibrolaryngoscopy (NFL) was suggestive of LPR. The patients were hospitalized for a 24-hour MII-pH. Patients with a congenital or acquired morbid history were excluded. Pathological LPR was considered if there were 3 or more acid reflux episodes at the pro ximal level in MII-pH. The frequency of traditional pH monitoring and altered MII-pH and the concordance between both methods were evaluated. RESULTS: 12 patients were recruited, 10 men, 6 to 15 years old. On 9/12, pathological LPR was confirmed by MII-pH, of which 2/9 had traditional pH measurements in normal ranges and 7/9 altered pH measurements. In 3 patients, LPR was ruled out by normal proximal MII-pH. The concordance between MII-pH and traditional pH monitoring was acceptable (kappa 0.4). CONCLUSIONS: 75% of the patients with dysphonia and suggestive NFL showed objective evidence of pathological LPR. Since only with the clinical evaluation, NFL and conventional pH monitoring it is not possible to diagnose LPR, we recommend perform MII-pH for greater diag nostic certainty, avoiding unnecessary treatment, and with unwanted effects in 25% of cases.

La respuesta sistémica Th17/IL-17A aparece antes del proceso neurodegenerativo en el hipocampo de ratas expuestas a bajas dosis de ozono / Systemic Th17/IL-17A response appears prior to hippocampal neurodegeneration in rats exposed to low doses of ozone

Introducción: La exposición a dosis bajas de O3 conduce a un estado de estrés oxidativo. Algunos estudios muestran que el estado de estrés oxidativo puede modular tanto el SNC como la inflamación sistémica, que son importantes para el desarrollo de la enfermedad de Alzheimer. Objetivo: Evaluar la frecuencia de células tipo Th17, la concentración de IL-17A en plasma y la inmunorreactividad del hipocampo a IL-17A en ratas expuestas a dosis bajas de O3.Métodos: Ciento ocho ratas Wistar machos fueron divididas en 6 grupos (n = 18) con los siguientes tratamientos: control (sin O3) y O3 (0,25 ppm, diario por 4h) durante 7, 15, 30, 60 y 90 días. De cada grupo se decapitaron 12 animales, se tomó una muestra de sangre periférica para aislar el plasma y las células mononucleares. La IL-17A plasmática se evaluó mediante LUMINEX y la frecuencia de células de tipo Th17 por citometría de flujo. Las ratas restantes se anestesiaron y se perfundieron para inmunohistoquímica en el hipocampo. Resultados: Muestran que la exposición durante 7 días a O3 produce un aumento significativo en la frecuencia de células tipo Th17 y los niveles de IL-17A en sangre periférica. Sin embargo, existe una disminución de Th17/IL-17A en la periferia desde el día 15. También se encontró un aumento de IL-17A en el hipocampo desde los 30 días de exposición. Conclusión: El O3 produce un efecto sistémico a corto plazo de tipo Th17/IL-17A y un aumento de IL-17A en el tejido del hipocampo durante el proceso neurodegenerativo crónico

Introduction: Exposure to low doses of O3 leads to a state of oxidative stress. Some studies show that oxidative stress can modulate both the CNS and systemic inflammation, which are important factors in the development of Alzheimer disease (AD).Objective: This study aims to evaluate changes in the frequency of Th17-like cells (CD3+CD4+IL-17A+), the concentration of IL-17A in peripheral blood, and hippocampal immunoreactivity to IL-17A in rats exposed to low doses of O3. Methods: One hundred eight male Wistar rats were randomly assigned to 6 groups (n = 18) receiving the following treatments: control (O3 free) or O3 exposure (0.25 ppm, 4hours daily) over 7, 15, 30, 60, and 90 days. Twelve animals from each group were decapitated and a peripheral blood sample was taken to isolate plasma and mononuclear cells. Plasma IL-17A was quantified using LUMINEX, while Th17-like cells were counted using flow cytometry. The remaining 6 rats were deeply anaesthetised and underwent transcardial perfusion for immunohistological study of the hippocampus. Results: Results show that exposure to O3 over 7 days resulted in a significant increase in the frequency of Th17-like cells and levels of IL-17A in peripheral blood. However, levels of Th17/IL-17A in peripheral blood were lower at day 15 of exposure. We also observed increased IL-17A in the hippocampus beginning at 30 days of exposure. Conclusion: These results indicate that O3 induces a short-term, systemic Th17-like/IL-17A effect and an increase of IL-17A in the hippocampal tissue during the chronic neurodegenerative process

Indicaciones y cuidados de la traqueostomía en pediatría / Indications and care of the tracheostomy in pediatrics

Tracheostomy in children is an extremely delicate procedure, which consists in the creation of a stoma between the trachea and the skin. Among the most frequent indications are neurological disorders, obstruction of the upper airway or prolonged mechanical ventilation. Pediatric versus adult airway differences should be considered during surgery. In the postoperative period, hemorrhage, pneumothorax, pneumomediatin can occur. In the late postoperative period, accidental decannulation, false pathway, infection of the tracheostomy, and later formation of periostomal or endotracheal granulomas may occur. The care of the tracheostomy in the clinical unit must be with trained personnel and the family environment must be prepared for home care. As long as the tracheostomy persists, control of the airway superior and inferior to the tracheostomy must be maintained by fiber optic. Patients with neurological compromise or cardiopulmonary damage have a lower decannulation rate and a longer hospital stay.

La traqueostomía en niños es un procedimiento extremadamente delicado, que consiste en la creación de un ostoma entre la tráquea y la piel. Entre las indicaciones más frecuentes se encuentran trastornos neurológicos, obstrucción de la vía aérea superior o ventilación mecánica prolongada. Consideraciones a las diferencias de la vía aérea pediátrica versus del adulto deben tenerse en cuenta durante la cirugía. En el postoperatorio se puede presentar hemorragia, neumotórax y neumomediastino. En el postoperatorio tardío puede ocurrir decanulación accidental, falsa vía, infección de la traqueostomía, y más tardíamente formación de granulomas periostomales o endotraqueales. El cuidado de la traqueostomía en la unidad clínica debe ser con personal capacitado y se debe preparar el entorno familiar para el cuidado en el domicilio. Mientras persista la traqueostomía se debe mantener control por fibra óptica de la vía aérea superior e inferior a la traqueostomía. Los pacientes con compromiso neurológico o daño cardiopulmonar tienen menor tasa de decanulación y mayor tiempo en el hospital.

Ozone pollution, oxidative stress, synaptic plasticity, and neurodegeneration. / Contaminación por ozono, estrés oxidativo, plasticidad sináptica y neurodegeneración.

INTRODUCTION: Overpopulation and industrial growth result in an increase in air pollution, mainly due to suspended particulate matter and the formation of ozone. Repeated exposure to low doses of ozone, such as on a day with high air pollution levels, results in a state of chronic oxidative stress, causing the loss of dendritic spines, alterations in cerebral plasticity and in learning and memory mechanisms, and neuronal death and a loss of brain repair capacity. This has a direct impact on human health, increasing the incidence of chronic and degenerative diseases. DEVELOPMENT: We performed a search of the PubMed, Scopus, and Google Scholar databases for original articles and reviews published between 2000 and 2018 and addressing the main consequences of ozone exposure on synaptic plasticity, information processing in cognitive processes, and the alterations that may lead to the development of neurodegenerative diseases. CONCLUSIONS: This review describes one of the pathophysiological mechanisms of the effect of repeated exposure to low doses of ozone, which causes loss of synaptic plasticity by producing a state of chronic oxidative stress. This brain function is key to both information processing and the generation of structural changes in neuronal populations. We also address the effect of chronic ozone exposure on brain tissue and the close relationship between ozone pollution and the appearance and progression of neurodegenerative diseases.

Effect of Ozone Exposure on Dendritic Spines of CA1 Pyramidal Neurons of the Dorsal Hippocampus and on Object-place Recognition Memory in Rats.

The growth of many cities has generated an increase in the emission of environmental pollutants. Exposure to these pollutants has been associated with increased mortality worldwide. These pollutants, such as ozone, produce reactive oxygen species (ROS), which cause oxidative stress throughout the body. It has been observed that there is a relationship between chronic oxidative stress and the development of degenerative diseases typical of old age such as amyotrophic lateral sclerosis, Parkinson's disease, Alzheimer's disease, and Huntington's disease. The purpose of this research was to evaluate whether chronic exposure to ozone produces a deleterious effect on density and morphology of dendritic spines in CA1 of dorsal hippocampus and on learning and memory of object-place recognition. Rats were exposed to ozone or to ozone-free air for a period of 15, 30, 60, or 90 days. The principal results indicate that chronic oxidative stress induced by ozone produces a decrease in the density of dendritic spines, a decrease in thin and mushroom spine ratios, and an increase in stubby spine ratio, as well as a deficit in learning and memory of the object-place recognition task. These results indicate that chronic ozone exposure produces a loss in the inputs of CA1 neurons of the dorsal hippocampus, which may be the source of the cognitive deficits observed in the object-place recognition task, as indicated by the decrease in density of dendritic spines; these alterations are similar to those reported in some neurodegenerative diseases such as Alzheimer's disease.

Systemic Th17/IL-17A response appears prior to hippocampal neurodegeneration in rats exposed to low doses of ozone. / La respuesta sistémica Th17/IL-17A aparece antes del proceso neurodegenerativo en el hipocampo de ratas expuestas a bajas dosis de ozono.

INTRODUCTION: Exposure to low doses of O3 leads to a state of oxidative stress. Some studies show that oxidative stress can modulate both the CNS and systemic inflammation, which are important factors in the development of Alzheimer disease (AD). OBJECTIVE: This study aims to evaluate changes in the frequency of Th17-like cells (CD3+CD4+IL-17A+), the concentration of IL-17A in peripheral blood, and hippocampal immunoreactivity to IL-17A in rats exposed to low doses of O3. METHODS: One hundred eight male Wistar rats were randomly assigned to 6 groups (n=18) receiving the following treatments: control (O3 free) or O3 exposure (0.25ppm, 4hours daily) over 7, 15, 30, 60, and 90 days. Twelve animals from each group were decapitated and a peripheral blood sample was taken to isolate plasma and mononuclear cells. Plasma IL-17A was quantified using LUMINEX, while Th17-like cells were counted using flow cytometry. The remaining 6 rats were deeply anaesthetised and underwent transcardial perfusion for immunohistological study of the hippocampus. RESULTS: Results show that exposure to O3 over 7 days resulted in a significant increase in the frequency of Th17-like cells and levels of IL-17A in peripheral blood. However, levels of Th17/IL-17A in peripheral blood were lower at day 15 of exposure. We also observed increased IL-17A in the hippocampus beginning at 30 days of exposure. CONCLUSION: These results indicate that O3 induces a short-term, systemic Th17-like/IL-17A effect and an increase of IL-17A in the hippocampal tissue during the chronic neurodegenerative process.

Effect of exposure to low doses of ozone on interleukin 17A expression during progressive neurodegeneration in the rat hippocampus. / Efecto de la exposición a bajas dosis de ozono en la expresión de la interleucina 17A durante el proceso de neurodegeneración progresiva en el hipocampo de ratas.

INTRODUCTION: Chronic exposure to low doses of ozone causes oxidative stress and loss of regulation of the inflammatory response, leading to progressive neurodegeneration. OBJECTIVE: We studied the effect of chronic exposure to low doses of ozone on IL-17A concentration and expression in neurons, microglia, astrocytes, and T cells in the rat hippocampus. METHODS: We used 72 Wistar rats, divided into 6 groups (n=12): a control group (no ozone exposure) and 5 groups exposed to ozone (0.25ppm, 4h daily) for 7, 15, 30, 60, and 90 days. We processed 6 rats from each group to quantify IL-17A by ELISA; the remaining 6 were processed for immunohistochemistry (against IL-17A and GFAP, Iba1, NeuN, and CD3). RESULTS: The ELISA study data showed a significant increase in IL-17A concentrations in the 7-, 15-, 30-, and 60-day exposure groups, with regard to the control group (P<.05). Furthermore, they indicate that hippocampal neurons were the cells showing greatest immunoreactivity against IL-17A between 60 and 90 days of exposure to ozone; we also observed an increase in activated astrocytes in the 30- and 60-day exposure groups. CONCLUSION: Exposure to ozone in rats induces an increase in IL-17A expression, mainly in hippocampal neurons, accompanied by hippocampal astrocyte activation during chronic neurodegeneration, similar to that observed in Alzheimer disease in humans.

Resonancia magnética funcional: principios básicos y aplicaciones en neurociencias / Functional magnetic resonance imaging: basic principles and application in the neurosciences

La resonancia magnética funcional (RMf) es una herramienta avanzada para el estudio de las funciones cerebrales en sujetos sanos y pacientes neuropsiquiátricos, que logra identificar y localizar fenómenos específicos del metabolismo y la actividad neuronal. Comenzando por la detección de los cambios en la irrigación de una región que participa en una función, actualmente se han desarrollado aproximaciones más complejas que estudian la dinámica de las redes neuronales. Tanto en reposo como asociada a tareas, se ha aportado evidencia relativa al inicio, la evolución o la respuesta al tratamiento de diversas enfermedades. Los posibles artefactos asociados al registro y la complejidad de los diseños experimentales analíticos han generado abundante debate en torno a la técnica de la RMf. El objetivo del presente artículo es introducir al lector en las bases de la RMf, su interpretación y sus contribuciones al estudio de los mecanismos subyacentes a diversas afecciones del sistema nervioso

Functional magnetic resonance imaging (fMRI) is an advanced tool for the study of brain functions in healthy subjects and in neuropsychiatric patients. This tool makes it possible to identify and locate specific phenomena related to neuronal metabolism and activity. Starting with the detection of changes in the blood supply to a region that participates in a function, more complex approaches have been developed to study the dynamics of neuronal networks. Studies examining the brain at rest or involved in different tasks have provided evidence related to the onset, development, and/or response to treatment in various diseases. The diversity of the possible artifacts associated with image registration as well as the complexity of the analytical experimental designs has generated abundant debate about the technique behind fMRI. This article aims to introduce readers to the fundamentals underlying fMRI, to explain how fMRI studies are interpreted, and to discuss fMRI's contributions to the study of the mechanisms underlying diverse diseases of the nervous system

Functional magnetic resonance imaging: basic principles and application in the neurosciences. / Resonancia magnética funcional: principios básicos y aplicaciones en neurociencias.

Functional magnetic resonance imaging (fMRI) is an advanced tool for the study of brain functions in healthy subjects and in neuropsychiatric patients. This tool makes it possible to identify and locate specific phenomena related to neuronal metabolism and activity. Starting with the detection of changes in the blood supply to a region that participates in a function, more complex approaches have been developed to study the dynamics of neuronal networks. Studies examining the brain at rest or involved in different tasks have provided evidence related to the onset, development, and/or response to treatment in various diseases. The diversity of the possible artifacts associated with image registration as well as the complexity of the analytical experimental designs has generated abundant debate about the technique behind fMRI. This article aims to introduce readers to the fundamentals underlying fMRI, to explain how fMRI studies are interpreted, and to discuss fMRI's contributions to the study of the mechanisms underlying diverse diseases of the nervous system.

Coleoptera Associated with Decaying Wood in a Tropical Deciduous Forest.

Coleoptera is the largest and diverse group of organisms, but few studies are dedicated to determine the diversity and feeding guilds of saproxylic Coleoptera. We demonstrate the diversity, abundance, feeding guilds, and succession process of Coleoptera associated with decaying wood in a tropical deciduous forest in the Mixteca Poblana, Mexico. Decaying wood was sampled and classified into four stages of decay, and the associated Coleoptera. The wood was identified according to their anatomy. Diversity was estimated using the Simpson index, while abundance was estimated using a Kruskal-Wallis test; the association of Coleoptera with wood species and decay was assessed using canonical correspondence analysis. Decay wood stage I is the most abundant (51%), followed by stage III (21%). We collected 93 Coleoptera belonging to 14 families, 41 genera, and 44 species. The family Cerambycidae was the most abundant, with 29% of individuals, followed by Tenebrionidae with 27% and Carabidae with 13%. We recognized six feeding guilds. The greatest diversity of Coleoptera was recorded in decaying Acacia farnesiana and Bursera linanoe. Kruskal-Wallis analysis indicated that the abundance of Coleoptera varied according to the species and stage of decay of the wood. The canonical analysis showed that the species and stage of decay of wood determined the composition and community structure of Coleoptera.

Análisis del proceso de innovación curricular en la Escuela de Fonoaudiología de la Universidad de Chile / Curricular innovation process of the School of Speech & Language Pathology at University of Chile

El proceso de innovación curricular de la Facultad de Medicina de la Universidad de Chile ha implicado un desafío importante para autoridades, académicos y comunidad estudiantil. La universidad ha adoptado un modelo basado en las competencias que el estudiante debe demostrar en los distintos ámbitos de la disciplina, para dar cuenta del perfil del egreso. En este sentido, la carrera de Fonoaudiología ha construido una nueva malla curricular constituida por competencias, subcompetencias e indicadores de logro para cada uno de los dominios de formación. El rediseño curricular conlleva una renovación de las metodologías didácticas y una nueva mirada en relación con el proceso de enseñanza aprendizaje, situando al estudiante en un rol más activo. Gracias al levantamiento de demandas y necesidades formativas, se construyeron cinco dominios correspondientes a los ámbitos de realización del egresado en Fonoaudiología. En este artículo se describen y explican los elementosconstituyentes del nuevo currículum, detallando ámbitos relevantes y sujustificación en el plan formativo global de la Escuela de Fonoaudiología...

The process of curriculum innovation at the Faculty of Medicine at the Universityof Chile has implied an important challenge for authorities, faculty members, and students. The university has adopted a model based on competences which students have to demonstrate in different áreas of the discipline in order to accomplish the graduate profile. In this respect, the Speech & Language Pathology undergraduate program has developed a new curriculum based on competencies, subcompetencies and learning outcomes for each domain of the academic training. The new curriculum involves renewed didactic methodologies and a new approach'in the learning process. This would place the student in a more active role (learner centredness). Five domains corresponding to the different profesional áreas of the Speech & Language Pathology program were developed based on the demands and training needs. The present articledescribes and explains the constituent elements of the new curriculum,providing information about the áreas which were emphatically assumed by the Speech'&'Language'Pathology'Department...

Oxidative stress caused by ozone exposure induces ß-amyloid 1-42 overproduction and mitochondrial accumulation by activating the amyloidogenic pathway.

Oxidative stress is a major risk factor for Alzheimer's disease (AD) that has been suggested to be the trigger of AD pathology. However, whether oxidative damage precedes and contributes directly to the intracellular accumulation of beta amyloid 1-42 (ßA42) peptide remains a matter of debate. Chronic exposure to low doses of ozone similar to the levels during a day of high pollution in México City causes a state of oxidative stress that elicits progressive neurodegeneration in the hippocampi of rats. Several reports have demonstrated that the mitochondria are among the first organelles to be affected by oxidative stress and ßA42 toxicity and act as sites of the accumulation of ßA42, which affects energy metabolism. However, the mechanisms related to the neurodegeneration process and organelle damage that occur in conditions of chronic exposure to low doses of ozone have not been demonstrated. To analyze the effect of chronic ozone chronic exposure on changes in the production and accumulation of the ßA42 and ßA40 peptides in the mitochondria of hippocampal neurons of rats exposed to ozone, we examined the mitochondrial expression levels of Presenilins 1 and 2 and ADAM10 to detect changes related to the oxidative stress caused by low doses of ozone (0.25ppm). The results revealed significant accumulations of ßA42 peptide in the mitochondrial fractions on days 60 and 90 of ozone exposure along with reductions in beta amyloid 1-40 accumulation, significant overexpressions of Pres2 and significant reductions in ADAM10 expression. Beta amyloid immunodetection revealed that there were some intracellular deposits of ßA42 and that ßA42 and the mitochondrial markers OPA1 and COX1 colocalized. These results indicate that the time of exposure to ozone and the accumulation of ßA42 in the mitochondria of the hippocampal cells of rats were correlated. Our results suggest that the accumulation of the ßA42 peptide may promote mitochondrial dysfunction due to its accumulation and overproduction.

Tibolone prevents oxidation and ameliorates cholinergic deficit induced by ozone exposure in the male rat hippocampus.

Oxidative stress is related to the development of central nervous system diseases involving memory processes. Cholinergic system and memory processes are disrupted by ozone exposure. In rats, ozone induces motor disturbances and memory deficits as well as biochemical changes in brain regions related to memory processes. In this work, we analyzed the effect of chronic tibolone (TIB) administration in central nervous system, specifically the content of choline acetyltransferase, acetylcholinesterase, acetylcholine and oxidative stress markers in the hippocampus of male rats exposed to ozone. Our results reveal a neuroprotective effect of TIB treatment on neuronal damage induced by chronic ozone exposure. Furthermore, we suggest that TIB can prevent memory deficits by providing a protective effect against oxidative stress and the cholinergic system disruption induced by ozone exposure. Together, these findings present a potential neuroprotective effect of TIB in processes linked to memory deficits induced by aging or neurodegenerative diseases.

Dificultades de lenguaje en niños preescolares con antecedente de prematuridad extrema / Language difficulties in preschool children with a history of extreme prematurity

Introducción: Los niños prematuros son una población vulnerable a presentar dificultades en su desarrollo lingüístico posterior. Existe evidencia que los déficits verbales son frecuentes y que repercuten negativamente en la interacción social y en el aprendizaje escolar. En Chile, estas habilidades no son evaluadas por el programa de seguimiento de prematuros, desconociéndose la magnitud de este problema. El objetivo fue describir las dificultades del lenguaje en un grupo de prematuros extremos en edad preescolar. Pacientes y Método: Treinta niños entre 4 y 5 años de edad, con antecedente de prematuridad extrema y sin hipoacusia ni daño neurológico severo, fueron evaluados con pruebas de lenguaje en el Policlínico de Seguimiento de Prematuros del Centro de Referencia de Salud Cordillera Oriente. Resultados: Un 73,3 por ciento de los niños presentó déficit en algún área del lenguaje evaluada. De ellos, un 77,3 por ciento presentaron dificultades comprensivas y expresivas. En este grupo, un 86,4 por ciento evidenció dificultades en habilidades narrativas relevantes para el aprendizaje escolar. Discusión: Una alta proporción de niños prematuros presenta dificultades de lenguaje en la etapa preescolar, lo que hace necesario incluir programas de intervención específicos que promuevan un mejor desarrollo del lenguaje en esta población.

Introduction: Preterm infants are prone to present language development difficulties. There is evidence that verbal deficits are common and adversely affect social interaction as well as school learning. In Chile, these skills are not evaluated by the premature follow-up program; therefore, the extent of this problem is unknown. The objective of this study is to describe the language difficulties of a group of preschoolers with a history of extreme prematurity. Patients and Methods: Thirty children aged 4 and 5 years old, with a history of extreme prematurity, but without severe neurological damage or hearing loss were evaluated through language tests at the Premature Follow-up Polyclinic of the Eastern Cordillera Health Reference Center. Results: 73.3 percent of the children assessed had deficits in some area of the language. Of these, 77.3 percent had comprehensive and expressive difficulties. In this group, 86.4 percent showed significant difficulties in narrative skills. Discussion: A high preterm infant proportion presents language difficulties in preschool, resulting in the need of including specific intervention programs that promote better language development for this population.

Quaternary origin and genetic divergence of the endemic cactus Mammillaria pectinifera in a changing landscape in the Tehuacán Valley, Mexico.

The endemic Mexican cactus, Mammillaria pectinifera, shows low dispersal capabilities and isolated populations within the highly dissected landscape of Tehuacán Valley. These characteristics can restrict gene flow and act upon the genetic divergence and speciation in arid plants. We conducted a phylogeographic study to determine if the origin, current distribution, and genetic structure of M. pectinifera were driven by Quaternary geomorphic processes. Sequences of the plastids psbA-trnH and trnT-trnL obtained from 66 individuals from seven populations were used to estimate genetic diversity. Population differentiation was assessed by an analysis of molecular variance. We applied a stepwise phylogenetic calibration test to determine whether species origin and genetic divergence among haplotypes were temporally concordant with recognizable episodes of geomorphic evolution. The combination of plastid markers yielded six haplotypes, with high levels of haplotype diversity (h = 0.622) and low nucleotide diversity (π = 0.00085). The populations were found to be genetically structured (F(ST) = 0.682; P < 0.00001), indicating that geographic isolation and limited dispersal were the primary causes of genetic population differentiation. The estimated origin and divergence time among haplotypes were 0.017-2.39 and 0.019-1.237 mya, respectively, which correlates with Pleistocene tectonics and erosion events, supporting a hypothesis of geomorphically-driven geographical isolation. Based on a Bayesian skyline plot, these populations showed long term demographic stability, indicating that persistence in confined habitats has been the main response of this species to landscape changes. We conclude that the origin and haplotype divergence of M. pectinifera were a response to local Quaternary geomorphic evolution.

[Language difficulties in preschool children with a history of extreme prematurity]. / Dificultades de lenguaje en niños preescolares con antecedente de prematuridad extrema.

INTRODUCTION: Preterm infants are prone to present language development difficulties. There is evidence that verbal deficits are common and adversely affect social interaction as well as school learning. In Chile, these skills are not evaluated by the premature follow-up program; therefore, the extent of this problem is unknown. The objective of this study is to describe the language difficulties of a group of preschoolers with a history of extreme prematurity. PATIENTS AND METHODS: Thirty children aged 4 and 5 years old, with a history of extreme prematurity, but without severe neurological damage or hearing loss were evaluated through language tests at the Premature Follow-up Polyclinic of the Eastern Cordillera Health Reference Center. RESULTS: 73.3% of the children assessed had deficits in some area of the language. Of these, 77.3% had comprehensive and expressive difficulties. In this group, 86.4% showed significant difficulties in narrative skills. DISCUSSION: A high preterm infant proportion presents language difficulties in preschool, resulting in the need of including specific intervention programs that promote better language development for this population.

Extracción endoscópica de cuerpos extraños digestivos / Endoscopic extraction of digestive foreign bodies

Introducción: La ingestión de cuerpo extraño (CE) es frecuente en la infancia, requiriendo en el 10-20 por ciento de los casos extracción endoscópica. El objetivo de este trabajo fue analizar las características demográficas, clínicas y endoscópicas de los pacientes con ingesta de CE que requieren manejo endoscópico. Pacientes y Método: Estudio de cohorte prospectivo. Se incluyen los pacientes derivados al servicio de urgencia de Clínica Alemana de Santiago para extracción de cuerpo extraño entre noviembre de 2007-noviembre de 2011. Se registran variables demográficas, clínicas y endoscópicas, clasificando la sintomatología en respiratoria, digestiva y otros. Se evaluaron factores de riesgo y complicaciones. Resultados: 170 pacientes, 52,4 por ciento varones, edad promedio de 4 años y 3 meses. En 78,5 por ciento la ingestión de CE ocurrió en el hogar, el 82,1por ciento consultó en las primeras 2 h. Los síntomas más comunes post ingestión fueron digestivos, respiratorios y dolor local. La localización del CE fue con radiografía simple en 87,6 por ciento. En el 91,8 por ciento se extrajo el CE. Localización: 1,3 por ciento retrofaríngeo, 69,3 por ciento esófago, 23 por ciento estómago, 1,9 por ciento duodeno, 3,8 por ciento distal a duodeno. Los CE más frecuentes fueron los redondos (56,4 por ciento) y dentro de ellos las monedas, punzantes (24,1 por ciento), pilas (14,7 por ciento), imanes (2,9 por ciento) y otros de gran tamaño (1,8 por ciento). Se encontró lesión de mucosa en el 53,5 por ciento, requiriendo hospitalización el 9,8 por ciento de los niños. Conclusiones: La ingestión de CE ocurre en el hogar y es más frecuente en pre escolares. El CE más frecuentes fue la moneda. La localización del CE fue con radiografía simple y no hubo fracaso ni complicaciones en la extracción endoscópica.

Introduction: The ingestion of a foreign body (FB) is very common in childhood, 10 to 20 percent of the cases require endoscopic removal. The aim of this study is to analyze the demographic, clinical and endoscopic characteristic of patients with FB ingestion requiring endoscopic management. Patients and Methods: The design corresponded to a Prospective Cohort Study. It included patients referred to the Clinica Alemana ER in Santiago in order to remove foreign bodies from their digestive systems between November 2007 and November 2011. Demographic, clinical and endoscopic characteristics were recorded, classifying the symptoms as respiratory, digestive and other manifestations. Risk factors and complications were evaluated. Results: 170 patients, 52.4 percent male with average age of four years and three months old. In 78.5 percent of the cases, the FB ingestion occurred at home, 82.1percent sought medical attention within two hours from the ingestion. Digestive, respiratory and local pain were among the most common symptoms. The location of the FB took place using simple x-ray in 87.6 percent of the cases. 91.8 percent of the FBs were extracted. Location: retropharyngeal 1.3 percent, 69.3 percent esophagus, stomach 23 percent duodenum 1.9 percent and 3.8 percent distal duodenum. Round FB were the most frequent (56.4 percent) like coins, sharp objects (24.1 percent), batteries (14.7 percent), magnets (2.9 percent) and other large items (1.8 percent). Mucosal lesion was found in 53.5 percent of the cases and 9.8 percent required hospitalization Conclusions: The ingestion of FB occurred at home, and it is most frequent in preschool children. The most common FB was a coin. The location of the FB was through x-ray and no failure or complications were described during the endoscopic removal.