Abundance and distribution of plant derived leaf waxes (long chain n-alkanes & fatty acids) from lake surface sediments along the west coast of southern South America: Implications for environmental and climate reconstructions.

Southern South America is the only large landmass that extends through the core of the Southern Westerly Winds (SWW), controlling hydrological and ecosystem variability in the region. In fact, the vegetation along the west coast changes from Temperate and Valdivian Rain Forest to the North Patagonian Evergreen Forest (ca. 42°S) due to the latitudinal influence of the SWW. Climate is an important driver of organic matter accumulation in lakes, hence changes in vegetation would be recorded in lacustrine sedimentary archives. This study evaluated leaf waxes contained in lake surface sediments as indicators of climate change along the west coast of southern South America, providing a biogeochemical dataset for ongoing and future (paleo)climate and environmental research. The fatty acid and n-alkane sediment leaf wax datasets are compared with latitudinal, orographic, and climatic (Mean Annual air Temperature [MAT] & Precipitation [MAP]) trends extracted from a monthly gridded reanalysis product of the Climate Forecast System Reanalysis. Fatty acids are more abundant than n-alkanes, with high abundances characterizing the transition between seasonal and year-round precipitation along the coast (ca. 42°S). The abundance of both leaf wax groups increases with MAP, suggesting precipitation as the main control on sedimentary leaf wax delivery to the lake sediments in the study area. The Carbon Preference Index (CPI) of the two groups show opposite trends, but both highlight the climate transition at ca. 42°S, and have a linear relationship with MAP. The opposite significant trends between n-alkane CPI and fatty acid CPI with MAP are interpreted as higher n-alkane production at much higher precipitation because leaf wax fatty acids are the precursors of n-alkanes. Hence, past periods during which these leaf waxes show opposite trends in CPI might be interpreted as a precipitation change, especially if additional information such as pollen, diatoms, chironomids and stable isotopes is available.

Classifying brain states and pupillary responses associated with the processing of old and new information.

Memory retrieval of consolidated memories has been extensively studied using "old-new tasks", meaning tasks in which participants are instructed to discriminate between stimuli they have experienced before and new ones. Significant differences in the neural processing of old and new elements have been demonstrated using different techniques, such as electroencephalography and pupillometry. In this work, using the data from a previously published study (Campos-Arteaga, Forcato et al. 2020), we investigated whether machine learning methods can classify, based on single trials, the brain activity and pupil responses associated with the processing of old and new information. Specifically, we used the EEG and pupillary information of 39 participants who completed an associative recall old-new task in which they had to discriminate between previously seen or new pictures and, for the old ones, to recall an associated word. Our analyses corroborated the differences in neural processing of old and new items reported in previous studies. Based on these results, we hypothesized that the application of machine learning methods would allow an optimal classification of old and new conditions. Using a Windowed Means approach (WM) and two different machine learning algorithms - Logistic Regression (WM-LR) and Linear Discriminant Analysis (WM-LDA) - mean classification performances of 0.75 and 0.74 (AUC) were achieved when EEG and pupillary signals were combined to train the models, respectively. In both cases, when the EEG and pupillary data were merged, the performance was significantly better than when they were used separately. In addition, our results showed similar classification performances when fused classification models (i.e., models created with the concatenated information of 38 participants) were applied to individuals whose EEG and pupillary information was not considered for the model training. Similar results were found when alternative preprocessing methods were used. Taken together, these findings show that it is possible to classify the neurophysiological activity associated with the processing of experienced and new stimuli using machine learning techniques. Future research is needed to determine how this knowledge might have potential implications for memory research and clinical practice.

Validación del instrumento Montreal Cognitive Assessment en español en adultos mayores de 60 años / Validation of the Spanish-language version of the Montreal Cognitive Assessment test in adults older than 60 years

Introducción: Existen pocas validaciones de la versión en español de la prueba Montreal Cognitive Assessment (MoCA-S) en Latinoamérica. Objetivo: Evaluar las propiedades psicométricas y la validez discriminativa del MoCA-S en adultos mayores de Santiago de Chile. Métodos: Ciento setenta y dos individuos agrupados según diagnóstico clínico basado en Clinical Dementia Rating (CDR) en: deterioro cognitivo leve tipo amnésico (DCL-a, n = 24), DCL no-amnésico (DCL-na, n = 24), demencia leve (n = 20) y 104 cognitivamente sanos fueron evaluados con el MoCA-S y Mini-Mental test de Folstein (MMSE) como prueba de contraste, para determinar la validez discriminativa del MoCA-S. Resultados: Los promedios ± desviación estándar de edad y escolaridad fueron 73 ± 6 y 11 ± 4, respectivamente, sin diferencias significativas entre los grupos. La consistencia interna fue buena (alfa de Cronbach 0,772), la fiabilidad interevaluador muy buena (coeficiente de correlación de Spearman 0,846 [p < 0,01]) y la fiabilidad intraevaluador (test-retest) fue 0,922 bilateral (p < 0,001). La prueba fue eficaz y válida para la detección del DCL-a (ABC = 0,903) y demencia leve (ABC = 0,957); menos eficaz en DCL no-a (ABC = 0,629). El punto de corte de mejor rendimiento para DCL-a fue < 21 y para demencia leve < 20; sensibilidad/especificidad de 75/82% y 90/86%, respectivamente. La escolaridad mostró una importante influencia en el puntaje, por ello se adicionaron 2 puntos para escolaridad < 8 años y un punto para escolaridad entre 8 y 12 años (MoCA-S1-2). El MoCA-S1-2 fue significativamente más discriminativo que el MMSE para diferenciar DCL-a y demencia. Conclusiones: El MoCA-S1-2 es una prueba breve, de fácil administración y útil para el diagnóstico de DCL-a y demencia leve

Introduction: Few studies have validated the Spanish-language version of the Montreal Cognitive Assessment (MoCA-S) test in Latin American populations. Objetive: To evaluate the psychometric properties and discriminant validity of the MoCA-S in elderly patients in Santiago de Chile. Methods: 172 individuals were grouped according to their clinical diagnosis based on the Clinical Dementia Rating (CDR) scale as follows: amnestic mild cognitive impairment (aMCI; n ± 24), non-amnestic MCI (naMCI; n ± 24), mild dementia (n ± 20), and cognitively normal (n ± 104). Participants were evaluated with both the MoCA-S and the Mini-Mental State Examination (MMSE) to determine the discriminant validity of the MoCA-S. Results: Mean age and years of schooling were 73 ± 6 and 11 ± 4 years, respectively, with no significant intergroup differences. The MoCA-S displayed good internal consistency (Cronbach's alfa: 0.772), high inter-rater reliability (Spearman correlation coefficient: 0.846; P < .01), and high intra-rater reliability (test-retest reliability coefficient: 0.922; P < .001). The MoCA-S was found to be an effective and valid test for detecting aMCI (AUC ± 0.903) and mild dementia (AUC ± 0.957); its effectiveness for detecting naMCI was lower (AUC ± 0.629). The optimal cut-off points for aMCI and mild dementia were < 21 and < 20, respectively, with sensitivity and specificity rates of 75% and 82% for aMCI and 90% and 86% for mild dementia. The level of education had a great impact on scores: as a result, 2 points were added for patients with less than 8 years of schooling and one point for patients with 8-12 years of schooling (MoCA-S1-2). The MoCA-S1-2 showed significantly greater discriminant validity than the MMSE for differentiating aMCI from dementia. Conclusions: The MoCA-S1-2 is a short, easy-to-use, and useful test for diagnosing aMCI and mild dementia

Validation of the Spanish-language version of the Montreal Cognitive Assessment test in adults older than 60 years. / Validación del instrumento Montreal Cognitive Assessment en español en adultos mayores de 60 años.

INTRODUCTION: Few studies have validated the Spanish-language version of the Montreal Cognitive Assessment (MoCA-S) test in Latin American populations. OBJETIVE: To evaluate the psychometric properties and discriminant validity of the MoCA-S in elderly patients in Santiago de Chile. METHODS: 172 individuals were grouped according to their clinical diagnosis based on the Clinical Dementia Rating (CDR) scale as follows: amnestic mild cognitive impairment (aMCI; n±24), non-amnestic MCI (naMCI; n±24), mild dementia (n±20), and cognitively normal (n±104). Participants were evaluated with both the MoCA-S and the Mini-Mental State Examination (MMSE) to determine the discriminant validity of the MoCA-S. RESULTS: Mean age and years of schooling were 73±6 and 11±4 years, respectively, with no significant intergroup differences. The MoCA-S displayed good internal consistency (Cronbach's α: 0.772), high inter-rater reliability (Spearman correlation coefficient: 0.846; P<.01), and high intra-rater reliability (test-retest reliability coefficient: 0.922; P<.001). The MoCA-S was found to be an effective and valid test for detecting aMCI (AUC±0.903) and mild dementia (AUC±0.957); its effectiveness for detecting naMCI was lower (AUC±0.629). The optimal cut-off points for aMCI and mild dementia were<21 and<20, respectively, with sensitivity and specificity rates of 75% and 82% for aMCI and 90% and 86% for mild dementia. The level of education had a great impact on scores: as a result, 2 points were added for patients with less than 8 years of schooling and one point for patients with 8-12 years of schooling (MoCA-S1-2). The MoCA-S1-2 showed significantly greater discriminant validity than the MMSE for differentiating aMCI from dementia. CONCLUSIONS: The MoCA-S1-2 is a short, easy-to-use, and useful test for diagnosing aMCI and mild dementia.

Organic matter geochemical signatures (TOC, TN, C/N ratio, δ13C and δ15N) of surface sediment from lakes distributed along a climatological gradient on the western side of the southern Andes.

Paleolimnological studies in western South America, where meteorological stations are scarce, are critical to obtain more realistic and reliable regional reconstructions of past climate and environmental changes, including vegetation and water budget variability. However, climate and environmental geochemical indicators must be tested before they can be applied with confidence. Here we present a survey of lacustrine surface sediment (core top, 0 to ~1cm) biogeochemical proxies (total organic carbon [TOC], total nitrogen [TN], carbon/nitrogen ratio [C/N ratio] and bulk organic δ13C and total δ15N) from a suite of 72 lakes spanning the transition from a Mediterranean climate with a patchwork of cultivated vegetation, pastureland, and conifers in central Chile to a rainy temperate climate dominated by broadleaf deciduous and evergreen forest further south. Sedimentary data are compared to the latitudinal and orographic climatic trends of the region based on the climatology (precipitation and temperature) produced with Climate Forecast System Reanalysis (CFSR) data and the modern Southern Hemisphere Westerly Winds (SWW) location. The geochemical data show inflection points at ~42°S latitude and ~1500m elevation that are likely related to the northern limit of influence of the SWW and elevation of the snow line, respectively. Overall the organic proxies were able to mimic climatic trends (Mean Annual Precipitation [MAP] and temperature [MAT]), indicating that they are a useful tool to be included in paleoclimatological reconstruction of the region.

Síndrome de la arteria mesentérica superior. Presentación de un caso y revisión de la literatura / Superior mesenteric artery syndrome. A case report and review of the literature

No disponible

Levobupivacaine absorption pharmacokinetics with and without epinephrine during TAP block: analysis of doses based on the associated risk of local anaesthetic toxicity.

PURPOSE: Cases of local anaesthetic systemic toxicity (LAST) periodically occur following transversus abdominal plane (TAP) blocks. The aim of this study was to characterize levobupivacaine absorption pharmacokinetics, with and without epinephrine, and estimate the risk of LAST, based on a previously reported toxic threshold. METHODS: Previously reported data from 11 volunteers receiving ultrasound-guided TAP blocks with and without epinephrine on two independent occasions were analysed. Serial venous concentrations were measured for 90 min. A pharmacokinetic analysis was performed using the NONMEM statistical programme. The use of epinephrine in the solution was included in the analysis of covariates. The associated risk of LAST symptoms associated with different levobupivacaine dose schemes with and without epinephrine was estimated in 1000 simulated subjects. RESULTS: A one-compartment first-order input and elimination model adequately fit the levobupivacaine data. Epinephrine prolonged the levobupivacaine absorption half-life {4.22 [95 % confidence interval (CI) 2.53-6.50] vs. 7.02 [95 % CI 3.74-14.1]; p < 0.05} and reduced its relative bioavailability (0.84; 95 % CI 0.72-0.97; p < 0.05) The derived model predicts that levobupivacaine dose schemes should be halved from 3 mg kg(-1) body weight with epinephrine to 1.5 mg kg(-1) without epinephrine to obtain a comparable risk of anaesthetic toxicity symptoms of approximately 0.1 %. CONCLUSIONS: Our results strongly support the addition of epinephrine to the local anaesthetic solution, especially when doses of levobupivacaine of >1.5 mg kg(-1) are required. Recommendations regarding the maximum allowable doses of local anaesthetics should consider population analysis to determine safer dosage ranges.

[Superior mesenteric artery syndrome. A case report and review of the literature]. / Síndrome de la arteria mesentérica superior. presentación de un caso y revisión de la literatura.

INTRODUCTION: Superior mesenteric artery syndrome (SMAS) or Wilkie syndrome is a rare disease in the pediatric population. Although their causes are generally well known, the clinic is often subtle, so reaching a diagnosis can be difficult. There are medical and surgical treatment options, which depend on each patient. CLINICAL CASE: Our study shows an atypical case of SAMS, which debuted in a 13-year-old boy without previous diseases, and without a history of risk factors for this pathology. Its symptomatology, the diagnostic process and the treatment are described. COMMENTS: The clinical presentation and age of the patient make an interesting case, so we make a review about the pathology, its current diagnostic methods and available therapeutic alternatives.

INTRODUCCION: El síndrome de la arteria mesentérica superior (SAMS) o síndrome de Wilkie es una patología poco frecuente en la población pediátrica. A pesar de que sus causas son en general bien conocidas, la clínica muchas veces es poco sugerente, por lo que llegar al diagnóstico puede ser difícil. Existen opciones médicas y quirúrgicas de tratamiento, que dependen de cada paciente. CASO CLINICO: Nuestro trabajo muestra un caso atípico de SAMS, que debutó en un adolescente de 13 años sin enfermedades previas, y sin antecedentes de factores de riesgo descritos para esta patología. Se describen su sintomatología, el proceso diagnóstico y el tratamiento realizado. COMENTARIOS: La presentación clínica y la edad del paciente hacen a este caso particularmente interesante, por lo que hicimos una revisión teórica acerca de la patología, sus métodos diagnósticos actuales, y las alternativas terapéuticas disponibles.

Bioética y pediatría: relación médico-familia del paciente / Bioethics in pediatrics: relationship physician-family patients

La bioética como una disciplina que pone en perspectiva los problemas o dilemas que debe enfrentar el médico con sus pacientes, presenta desafíos particulares en el ámbito pediátrico. Debemos enfrentar una relación médico familia, que es mucho más complejo que la relación médico paciente de los adultos. Se presentan la relación del equipo médico con la familia de los pacientes pediátricos, y las dificultades que enfrentan los diversos grupos de personas que lo conforman. Se enuncian las dificultades más frecuentes, en la práctica pediátrica, y la forma como se intenta solucionarlas.

Bioethics is considered a discipline that help to understand and analyze problems and dilemmas that confront the physician and their patients. It presents particular challenges in the pediatric field. We deal with the family – physician relationship, which is much more complex than the physician-patient relationship in adults medicine. The article presents the relation of the medical team and Also the author illustrates the most frequent problems in pediatric practice and how they face them.

Partograma en mujeres multíparas con manejo médico del trabajo de parto / Graphic analyses of labor in multiparous womens with medical management

Antecedentes. La evaluación gráfica del parto fue descrito originalmente por Friedman, sin embargo, una descripción de la evolución del trabajo de parto con un manejo médico contemporáneo no ha sido completamente evaluado. Objetivo: Analizar el efecto de un manejo médico estandarizado del trabajo de parto, que incluye anestesia regional, rotura artificial de membranas y conducción ocitócica, sobre la fase activa del trabajo de parto en multíparas. Método. Análisis retrospectivo de 130 multíparas en trabajo de parto espontáneo, que ingresaron con 3 a 4 cm de dilatación. Resultados. Se observó una duración de la fase activa del trabajo de parto de aproximadamente 3,5 horas, con una progresión promedio de 1,5 cm/ h, produciéndose la mayor progresión entre los 7 y 9 cm de dilatación con 1,9 cm/h. La segunda fase del trabajo de parto presento una duración promedio de 28 minutos. Conclusiones. Nuestros resultados muestran que el manejo médico estandarizado del trabajo de parto no reduce los tiempos de la fase activa ni de la segunda fase en multíparas. Creemos que es necesario implementar estudios randomizados para determinar la influencia de este tipo manejo del trabajo de parto en la incidencia de cesáreas.

Environmental evidence of fossil fuel pollution in Laguna Chica de San Pedro lake sediments (Central Chile).

This paper describes lake sediment spheroidal carbonaceous particle (SCP) profiles from Laguna Chica San Pedro, located in the Biobío Region, Chile (36 degrees 51' S, 73 degrees 05' W). The earliest presence of SCPs was found at 16 cm depth, corresponding to the 1915-1937 period, at the very onset of industrial activities in the study area. No SCPs were found at lower depths. SCP concentrations in Laguna Chica San Pedro lake sediments were directly related to local industrial activities. Moreover, no SCPs were found in Galletué lake (38 degrees 41' S, 71 degrees 17.5' W), a pristine high mountain water body used here as a reference site, suggesting that contribution from long distance atmospheric transport could be neglected, unlike published data from remote Northern Hemisphere lakes. These results are the first SCP sediment profiles from Chile, showing a direct relationship with fossil fuel consumption in the region. Cores were dated using the 210Pb technique.

Anestesia local en cirugía vitreorretinal y de polo anterior en pacientes menores de 20 años / Local anaesthesia for vitreoretinal and anterior segment surgery in patient under 20 year old

Introducción: Pese al aumento en el uso de anestesia regional en cirugía oftalmológica, esta técnica es aún poco usada en pacientes jóvenes. Objetivo: Analizar la utilidad y seguridad de la anestesia regional en pacientes menores de 20 años operados en la Fundación Oftalmológica Los Andes. Método: Revisión retrospectiva de 45 cirugías vitreorretinales y 27 cirugías de polo anterior, en menores de 20 años, realizadas con anestesia regional en nuestro servicio entre los años 2002 al 2004. Resultados: La edad fluctuó entre 12 y 20 años. No se reportaron complicaciones anestésicas intraoperatorias serias y en todos los casos se realizó el procedimiento sin inconvenientes, tanto para el cirujano como para el paciente. Los requerimientos de sedación fueron mayores en los pacientes sometidos a cirugía vitreorretinal (p<0,05). No hubo casos de conversión a anestesia general. Conclusión: La anestesia regional es una alternativa segura y bien tolerada, aún en cirugía vitreorretinal compleja.

Manejo y resultado perinatal en pacientes con lupus eritematoso sistémico / Management and perinatal results in patients with systemic lupus erythematosus

Se presenta el control prenatal y resultado materno-perinatal de un grupo de pacientes portadoras de lupos eritematoso sistémico que controlaron su embarazo y resolvieron su parto durante el lapso de un año en la maternidad del Hospital Clínico de la Pontificia Universidad Católica de Chile. Mostramos además una suscinta revisión crítica de la literatura respecto de esta asociación. Evidenciamos que un adecuado diagnóstico prenatal de la enfermedad, junto a un control estricto multidisciplinario de esta patología durante el embarazo, permite reducir los riesgos maternos y perinatales

[Differential phenomenology of the paranoid psychoses in epilepsy]. / Fenomenología diferencial de las psicosis paranoides en la epilepsia.

First, the author makes reference to the psycho pathological and nosological questions associated with paranoid and schizophrenia-like psychoses in epilepsy and in particular to the non resolved problem of a distinction between these epileptic syndromes and the ones of schizophrenia. Starting from a phenomenological analysis of basic existential structures such as encounter or interpersonality, temporality and spatiality in a typical case of paranoid psychosis in epilepsy, the author tries to establish formal criteria which allow to distinguish these psychoses from schizophrenia. Thus it could be demonstrated that the structure of the encounter in the psychotic epileptic is quite conserved, both in what refers to the real and the delusional partner. His spatiality is characterized by the phenomenon of narrowness and his temporality by harassment, being necessary to underline the fact that, unlike what happens in schizophrenia, in the paranoid psychoses of epilepsy the space maintains its unity and the time its continuity. We could summarize the substantive difference between both types of paranoid psychoses with the following words: in paranoid syndromes in epilepsy what occurs is a change of state "within the world", while in schizophrenia it is a rather a modification of the "being-in-the world" itself or, with other words, it deals with a going out from the world constituted as community.