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La literatura ha hecho hincapié en la centralidad que cumplen los entornos alimentarios en las elecciones alimentarias y en el estado nutricional de la población. Objetivo: identificar las percepciones de padres, madres y apoderados, profesionales de establecimientos educacionales, funcionarios municipales, y feriantes pertenecientes a la zona sur de Santiago de Chile, respecto a las barreras y limitaciones de la puesta en práctica de una alimentación saludable en el ambiente alimentario escolar. Método: se realizaron seis grupos focales agrupando a 50 actores claves vinculados a los establecimientos educacionales de Ciudad Sur utilizando una muestra no probabilística. Se aplicó un análisis de contenido mediante la técnica de codificación temática buscando relevar los universos semánticos emergentes. Resultados: se identificaron nueve barreras, o semánticas, que caracterizan limitantes a la realización de la alimentación saludable en los entornos escolares desde la perspectiva de los participantes: la familia, kioscos escolares, la salida de los establecimientos escolares, gusto, determinantes socioeconómicos, política pública, falta de conocimiento, publicidad y disponibilidad de productos sin sellos. Conclusiones: las limitaciones asociadas al ambiente alimentario doméstico tienen una representación significativamente alta (47,9%) y contienen un carácter de responsabilización individual en su enunciación. Esta cultura explicativa es opuesta a la evidencia científica y académica respecto al funcionamiento de la conducta alimentaria, y a la centralidad de los ambientes alimentarios respecto a la facilitación u obstaculización del consumo de alimentos saludables o adecuados.

Literature has emphasized on food environments centrality in food choices and nutritional status. Objective: identify social perceptions of fathers, mothers and guardians, professionals from educational establishments, municipal officials, and stallholders belonging to the southern area of Santiago de Chile, regarding limitations of healthy diet implementation on school environments. Method: six focus groups were carried out grouping 50 key actors linked to educational establishments using a non-probabilistic sample. A content analysis was applied through thematic coding technique seeking to reveal emerging semantic universes. Results: Nine barriers, or semantics, were identified characterizing limitations to healthy eating habits in school environments: family, school kiosks, leaving school establishments, taste, socioeconomic determinants, public policy, lack of knowledge, publicity, and availability of products without seals. Conclusions: limitations associated with domestic food environment have a significantly high representation (47,9%) and contain an individualized responsibility feature. This explanatory culture is opposed to scientific and academic evidence regarding the functioning of eating behavior, and the centrality of food environments facilitating or hindering healthy food consumption.

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Exposure to heavy metals may cause the overproduction of reactive oxygen species, generating oxidative stress and consequently, various harms to human health. The soil surrounding the Ventanas Industrial Complex, in Puchuncaví and Quintero municipal districts on the central Chilean coast, contains heavy metal concentrations (As, Cu, Pb, Zn, among others) that far exceed the maximum permissible levels established by Italian soil standards (used as a reference). This study aimed to investigate the potential association between heavy metal exposure in humans and the levels of oxidative stress biomarkers in inhabitants of these locations. We took blood samples from 140 adults living in sites with high concentrations of heavy metals in the soil and compared them with blood samples from 140 adults living in areas with normal heavy metal concentrations. We assessed lipid peroxidation, damage to genetic material, and Total Antioxidant Capacity in these blood samples. Our results indicate an association between oxidative damage and heavy metal exposure, where the inhabitants living in exposed areas have a higher level of DNA damage compared with those living in control areas. Given that DNA damage is one of the main factors in carcinogenesis, these results are of interest, both for public health and for public policies aimed at limiting human exposure to environmental pollution.

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Cereal ß-glucans are beneficial health ingredients that reduce cholesterolemia and postprandial glycaemia. However, their impact on digestive hormones and gut microbiota is not yet fully established. Two randomized, double-blind, controlled studies were conducted. In the first study, 14 subjects ingested a breakfast with or without ß-glucan from oats (5.2 g). Compared to the control, ß-glucan increased orocecal transit time (p = 0.028) and decreased mean appetite score (p = 0.014) and postprandial plasma ghrelin (p = 0.030), C-peptide (p = 0.001), insulin (p = 0.06), and glucose (p = 0.0006). ß-glucan increased plasma GIP (p = 0.035) and PP (p = 0.018) without affecting leptin, GLP-1, PYY, glucagon, amylin, or 7α-hydroxy-4-cholesten-3-one, a biomarker of bile acid synthesis. In the second study, 32 subjects were distributed into 2 groups to ingest daily foods with (3 g/day) or without ß-glucan for 3 weeks; stools were collected before/after treatment. No changes in fecal microbiota composition/diversity (deep sequencing) were detected with ß-glucans. These results indicate that acute intake of 5 g ß-glucan slows transit time and decreases hunger sensation and postprandial glycaemia without affecting bile-acid synthesis, these changes being associated with decreased plasma insulin, C-peptide, and ghrelin, and increased plasma GIP and PP. However, regular daily intake of 3 g ß-glucan is not sufficient to have an effect on fecal microbiota composition.

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Introducción: La consulta nutricional es la primera línea de atención en niñas y niños en salud pública que presentan condiciones de malnutrición por déficit o exceso. Sin embargo, la atención a estos niños y niñas fue afectada por las movilizaciones sociales y la pandemia por COVID-19. Objetivo: Evaluar la tendencia de las consultas realizadas a menores de 9 años por profesional nutricionista en la región del Maule, Chile, desde el año 2017 a 2021. Métodos: Estudio descriptivo de corte longitudinal histórico basado en los datos de los Registros Estadísticos Mensuales (REM) del Servicio de Salud del Maule, las tendencias fueron analizadas con coeficiente de determinación (R2) mediante la regresión de Prais-Winsten. Resultados: Se analizaron 274.377 consultas nutricionales de niños/as menores de 9 años. 53,8% en clasificación de malnutrición por exceso y 12,1% en déficit. Se registró una disminución de 56,8% en las consultas nutricionales durante las movilizaciones sociales y un 92% al inicio de pandemia. Se observó una tendencia al aumento de las consultas por déficit nutricional, especialmente en menores de 12 meses (R2 0,633, β=4,45, p<0,001). Conclusión: La situación social y epidemiológica afectaron significativamente las atenciones nutricionales en salud pública. Es necesario dar una mayor visibilidad de los profesionales nutricionistas y promover el desarrollo de estrategias innovadoras para afrontar este escenario epidemiológico.

Background: The nutritional appointments is the first line of care for children with malnutrition or overweight in public primary health, but its normal functioning was affected by social mobilizations and the COVID-19 pandemic. Objective: To evaluate trends in consultations among children under 9 years of age in the Maule region, Chile, between 2017 and 2021. Methods: Descriptive longitudinal study based on data from the Monthly Statistical Records (REM) of the Maule Health Service, the trends were analyzed with coefficient of determination (R2) using Prais-Winsten regression. Results: 274,377 nutritional consultations were analyzed, of which 53.8% were overweight and 12.1% with malnutrition. A 56.8% decrease in nutritional consultations was recorded during social mobilizations and 92% at the beginning of the pandemic. A tendency to increase consultations due to malnutrition was observed, especially in children under 12 months of age (R2 0.633, β=4.45, p<0.001). Conclusion: The social and epidemiological situations significantly affected nutritional care in public health. It is necessary to give nutrition professionals greater visibility and promote the development of innovative strategies to deal with this epidemiological scenario.

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OBJECTIVE: The purpose of the current study was to cross-culturally adapt and validate an online questionnaire to assess eating habits and physical activity of university students under confinement due to coronavirus disease (COVID-19). DESIGN: Generation of a cross-sectional online survey to university students conducted during confinement due to COVID-19. The study was divided into two phases. SETTINGS: Students, Chile. PARTICIPANTS: Phase 1 considered the process of translation and back translation, expert panel, cultural adaptation and the generation of a pilot to validate a preliminary format of the questionnaire. In Phase 2, information from the instrument was collected from two hundred and sixty-eight university students, ages 16 to 30 years old, with a mean age of 21·6 (3·3) The major proportion of participants were female (82 %). RESULTS: The adapted questionnaire was statistically validated in three dimensions: (A) eating habits and behaviours during quarantine, (B) perception of risk and (C) physical activity changes during the quarantine. The reliability of Cronbach's α for dimensions A, B and C was 0·59, 0·85 and 0·97, respectively. The complete questionnaire obtained 0·61 in internal consistency and 0·61 (0·58-0·67) ICC reliability. A statistically significant positive correlation matrix was observed. CONCLUSIONS: This questionnaire is a practical tool to obtain accurate information about the relation of COVID-19 confinement on people's eating habits and physical activity. Therefore, it could contribute to establishing appropriate strategies to prevent negative effects on people's health.

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Foot traffic, conversion rate, and total sales during a period of time may be considered to be important indicators of store performance. Forecasting them may allow for business managers plan stores operation in the near future in an efficient way. This work presents a regression method that is able to predict these three indicators based on previous data. The previous data includes values for the indicators in the recent past; therefore, it is a requirement to have gathered them in a suitable manner. The previous data also considers other values that are easily obtained, such as the day of the week and hour of the day of the indicators. The novelty of the approach that is presented here is that it provides a confidence interval for the predicted information and the importance of each parameter for the predicted output values, without additional processing or analysis. Real data gathered by Follow Up, a customer experience company, was used to test the proposed method. The method was tried for making predictions for up to one month in the future. The results of the experiments show that the proposed method has a comparable performance to the best methods proposed in the past that do not provide confidence intervals or parameter rankings. The method obtains RMSE of 0.0713 for foot traffic prediction, 0.0795 for conversion rate forecasting, and 0.0757 for sales prediction.

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The dopamine transporter (DAT) plays a crucial role in the regulation of brain dopamine (DA) homeostasis through the re-uptake of DA back into the presynaptic terminal. In addition to re-uptake, DAT is also able to release DA through a process referred to as DAT-mediated DA efflux. This is the mechanism by which potent and highly addictive psychostimulants, such as amphetamine (AMPH) and its analogues, increase extracellular DA levels in motivational and reward areas of the brain. Recently, we discovered that G protein ßγ subunits (Gßγ) binds to the DAT, and that activation of Gßγ results in DAT-mediated efflux - a similar mechanism as AMPH. Previously, we have shown that Gßγ binds directly to a stretch of 15 residues within the intracellular carboxy terminus of DAT (residues 582-596). Additionally, a TAT peptide containing residues 582 to 596 of DAT was able to block the Gßγ-induced DA efflux through DAT. Here, we use a combination of computational biology, mutagenesis, biochemical, and functional assays to identify the amino acid residues within the 582-596 sequence of the DAT carboxy terminus involved in the DAT-Gßγ interaction and Gßγ-induced DA efflux. Our in-silico protein-protein docking analysis predicted the importance of F587 and R588 residues in a network of interactions with residues in Gßγ. In addition, we observed that mutating R588 to alanine residue resulted in a mutant DAT which exhibited attenuated DA efflux induced by Gßγ activation. We demonstrate that R588, and to a lesser extent F5837, located within the carboxy terminus of DAT play a critical role in the DAT-Gßγ physical interaction and promotion of DA efflux. These results identify a potential new pharmacological target for the treatment of neuropsychiatric conditions in which DAT functionality is implicated including ADHD and substance use disorder.

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Although many authors have highlighted the importance of predicting people's health costs to improve healthcare budget management, most of them do not address the frequent need to know the reasons behind this prediction, i.e., knowing the factors that influence this prediction. This knowledge allows avoiding arbitrariness or people's discrimination. However, many times the black box methods (that is, those that do not allow this analysis, e.g., methods based on deep learning techniques) are more accurate than those that allow an interpretation of the results. For this reason, in this work, we intend to develop a method that can achieve similar returns as those obtained with black box methods for the problem of predicting health costs, but at the same time it allows the interpretation of the results. This interpretable regression method is based on the Dempster-Shafer theory using Evidential Regression (EVREG) and a discount function based on the contribution of each dimension. The method "learns" the optimal weights for each feature using a gradient descent technique. The method also uses the nearest k-neighbor algorithm to accelerate calculations. It is possible to select the most relevant features for predicting a patient's health care costs using this approach and the transparency of the Evidential Regression model. We can obtain a reason for a prediction with a k-NN approach. We used the Japanese health records at Tsuyama Chuo Hospital to test our method, which included medical examinations, test results, and billing information from 2013 to 2018. We compared our model to methods based on an Artificial Neural Network, Gradient Boosting, Regression Tree and Weighted k-Nearest Neighbors. Our results showed that our transparent model performed like the Artificial Neural Network and Gradient Boosting with an R2 of 0.44.

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Preparing a plan for reaction to a grave emergency is a significant first stage in disaster management. A group of experts can do such preparation. Best results are obtained with group members having diverse backgrounds and access to different relevant data. The output of this stage should be a plan as comprehensive as possible, taking into account various perspectives. The group can organize itself as a collaborative decision-making team with a process cycle involving modeling the process, defining the objectives of the decision outcome, gathering data, generating options and evaluating them according to the defined objectives. The meeting participants may have their own evidences concerning people's location at the beginning of the emergency and assumptions about people's reactions once it occurs. Geographical information is typically crucial for the plan, because the plan must be based on the location of the safe areas, the distances to move people, the connecting roads or other evacuation links, the ease of movement of the rescue personnel, and other geography-based considerations. The paper deals with this scenario and it introduces a computer tool intended to support the experts to prepare the plan by incorporating the various viewpoints and data. The group participants should be able to generate, visualize and compare the outcomes of their contributions. The proposal is complemented with an example of use: it is a real case simulation in the event of a tsunami following an earthquake at a certain urban location.

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RESUMEN Validar instrumentos de medición de datos es fundamental para constituir conocimiento certero y objetivo respecto a los hábitos en ingesta alimentaria. El artículo pretende adaptar y validar para el contexto de educación superior un cuestionario que originalmente es de atención primaria, y que se transforme en un insumo válido para medir hábitos alimentarios en estudiantes universitarios. Basados en un cuestionario validado por Pino, Díaz y López en el 2011, se ajustaron las preguntas para un contexto de educación terciaria. El instrumento se aplicó a una muestra estratificada de 405 estudiantes de pregrado de una universidad perteneciente al Consejo de Rectores de Chile (CRUCH) de la región del Maule. Los datos fueron procesados mediante el paquete estadístico SPSS 20, y contó con los respectivos resguardos éticos mediante consentimiento informado firmado. Siguiendo los pertinentes análisis estadísticos para la validación del instrumento, podemos dar cuenta de un cuestionario confiable y aceptable (α= 0,815), estableciéndose 10 dimensiones con 35 preguntas. Se concluye un instrumento válido y adaptado para ser aplicado en estudiantes con el fin de identificar sus hábitos alimentarios en educación superior.

ABSTRACT Validating data measurement instruments is essential to establish accurate and objective knowledge regarding dietary habits. This article aims to adapt and validate a questionnaire to measure dietary habits originally designed for the primary care setting for use in the context of higher education. Based on a questionnaire validated by Pino, Díaz and López in 2011, the questions were adjusted for a tertiary education context. The instrument was applied to a sample of 405 undergraduate students of a university belonging to the Council of Rectors of Chile (CRUCH) of the Maule region, stratified by college year. Data were analysed using SPSS 20; signed informed consent was obtained. Following the relevant statistical analysis for the validation of an instrument, 10 dimensions with 35 questions were established. Results indicated that the instrument is trustworthy and acceptable (α= 0.815). We conclude that the instrument is a valid adaptation and can be applied to higher education students in order to identify their eating habits.

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OBJECTIVE: To evaluate the prognosis of anatomical resection (AR) and non-anatomical resection (NAR) of hepatocellular carcinoma. METHOD: We carried-out a retrospective study on a prospective database between May 2002 and December 2016. A propensity score matching (PSM) was performed to compare the outcomes between the groups to avoid possible confusion biases, because of non-random assignment. RESULTS: We included 86 patients, divided into two groups: 39 in the AR group and 47 in the NAR group. After PSM, 17 were selected into each group. There were no differences in any of the demographic and tumor variables. Overall survival (OS) after PSM was 93.9 and 55.9% at 1 and 5 years, and overall disease-free survival (DFS) was 91 and 45.7%, respectively. There were no differences in OS and DFS between groups (p = 0.47 and p = 0.31). The regression analysis did not observe differences between the groups in OS (p = 0.47), nor in DFS (p = 0.31). No differences were observed between the groups in recurrences. NAR was tended to recurrence before and after PSM. The time of recurrence was similar between the groups. CONCLUSIONS: The resection method does not influence in the long-term outcomes nor the recurrence.

OBJETIVO: Evaluar el pronóstico de la resección anatómica (RA) y la resección no anatómica (RNA) de los pacientes sometidos a cirugía de carcinoma hepatocelular. MÉTODO: Estudio retrospectivo sobre una base de datos prospectiva entre mayo de 2002 y diciembre de 2016. Para evitar posibles sesgos de confusión, se realizó un estudio de emparejamiento por análisis de propensión (EAP). RESULTADOS: Se incluyeron 86 pacientes, divididos en dos grupos: 39 RA y 47 RNA. Tras el EAP, quedaron 17 en cada grupo. No hubo diferencias en las variables demográficas ni del tumor. La supervivencia global (SG) tras el EAP fue del 93.9 y el 55.9% al año y los 5 años, y la supervivencia libre de enfermedad (SLE) global fue del 91 y el 45.7%, respectivamente. No se observaron diferencias entre los grupos (p = 0.47 y p = 0.31). El análisis de regresión no halló relación de los grupos con la SG (p = 0.47) ni con la SLE (p = 0.31). Respecto a la recidiva, no hubo diferencias. La RNA presenta mayor tendencia a la recidiva. Tampoco se encontraron diferencias en cuanto al tiempo de aparición de la recidiva. CONCLUSIONES: El tipo de resección hepática en el tratamiento del hepatocarcinoma no influye en los resultados a largo plazo ni en la aparición de recidiva.

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OBJECTIVES: To evaluate the effect of ZnO, TiO2 and SiO2 nanoparticles on cell viability and expression of the interleukin 7, interleukin 3, and granulocyte-macrophage colony stimulating factor (GM-CSF) genes in Mus musculus. MATERIAL AND METHODS: Red bone marrow was extracted from five Balb/c mice for the analysis of cell viability using the MTT test. The mice were divided into two groups of five each: one group was inoculated intraperitoneally with 0.5, 1.0, 2.5, 5.0, and 10 mg/kg of ZnO and SiO2 nanoparticles, respectively, and the other group was inoculated with 5.0, 10.0, 15.0, 20.0, and 25 mg/kg of TiO2 nanoparticles, respectively. Thirty hours later, RNA was extracted from the red bone marrow of the mice in both groups for gene expression analysis using quantitative PCR and RT-PCR. RESULTS: ZnO and SiO2 nanoparticles reduced cell viability in a dose-dependent manner by 37% and 26%, respectively, starting at a dose of 1 mg/kg. TiO2 nanoparticles at 5 mg/kg and 10 mg/kg reduced the gene expression of interleukins 7 and 3 by 55.3% and 70.2%, respectively, and SiO2 nanoparticles caused the greatest decrease (91%) in the expression of GM-CSF. ZnO nanoparticles reduced the expression of GM-CSF starting at doses of 20 mg/kg and 25 mg/kg. CONCLUSIONS: ZnO, SiO2 and TiO2 nanoparticles affect cell viability and gene expression in the mouse bone marrow.

OBJETIVOS: Evaluar el efecto de las nanopartículas de ZnO, TiO2 y SiO2 sobre la viabilidad celular y la expresión génica de las interleuquinas 7 y 3 y del factor estimulante de colonias de granulocito - macrófago (GM-CSF) en Mus musculus. MATERIALES Y MÉTODOS: Se extrajo médula ósea roja de cinco roedores (Balb/c) para el estudio de viabilidad celular mediante la prueba de MTT. Por otro lado, grupos cinco roedores fueron inoculados vía intraperitoneal con dosis de 0,5; 1; 2,5; 5 y 10 mg/kg de nanopartículas de ZnO y SiO2 y de 5; 10; 15; 20 y 25 mg/kg de nanopartículas de TiO2, 30 h después, se obtuvo el ARN a partir de la médula ósea roja para los análisis de expresión génica empleando las técnicas de PCR y RT-PCR cuantitativa. RESULTADOS: Las nanopartículas de ZnO y SiO2 redujeron la viabilidad celular de una manera dosis-dependiente en un 37 y 26%, respectivamente, a partir de una dosis de 1 mg/kg. En cuanto al efecto sobre la expresión génica, a las dosis 5 y 10 mg/kg, las nanopartículas de TiO2 redujeron en mayor porcentaje la expresión de las interleuquinas 7 y 3 (55,3 y 70,2% respectivamente), con respecto a la expresión del GM-CSF, el mayor porcentaje de reducción lo produjo las nanopartículas de SiO2 (91%). Las nanopartículas de ZnO redujeron a partir de las dosis de 20 y 25 mg/kg. CONCLUSIONES: Las nanopartículas de ZnO, SiO2 y TiO2 alteran la viabilidad celular y la expresión génica en la médula ósea de ratón.

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RESUMEN Objetivo: Describir las características sobre el uso del bastón y la prevalencia de caídas en adultos mayores de la comunidad que han recibido ayuda técnica en un Centro de Salud Familiar. Material y método: Estudio cuantitativo, descriptivo y transversal. La muestra correspondió a 64 adultos mayores de entre 60 y 94 años. Para recolectar los datos se utilizó un cuestionario que evaluó variables sociodemográficas, de salud, uso de bastón y caídas. El análisis estadístico se realizó mediante el paquete SPSS. Se utilizó consentimiento informado, considerando los lineamientos sobre investigación y confidencialidad de la información dispuestos en Chile. Resultados: El 95,3% refirió saber el motivo de uso del bastón; el 7,8% utiliza el bastón cuando se moviliza dentro de la casa, el 45,3% cuando se moviliza fuera de la casa, el 46,9% cuando se moviliza por todas partes; y el 48,4% expresó que no le agrada utilizar el bastón. La prevalencia de caídas en los últimos seis meses fue de 73%; de quienes presentaron caídas el 61% no estaba usando el bastón al momento de caer, y el 94% expresó tener miedo de sufrir una caída. Conclusión: Los resultados muestran que un alto porcentaje de adultos mayores no está cumpliendo con el uso del bastón, por lo tanto el objetivo de su entrega no se está logrando. Se debe incluir la evaluación y educación del uso del bastón como una actividad que forme parte del control de salud del adulto mayor.

ABSTRACT Aim: To describe the characteristics of cane use and prevalence of falls in community-dwelling older adults who have received technical assistance in a Family Health Center. Method: Quantitative, descriptive and cross-sectional study. Sample consisted of 64 older adults between 60 and 94 years of age. A questionnaire addressing socio-demographics, health, cane use and fall-related information was used to collect the data. Statistical analysis was performed with SPSS. An informed consent form was delivered and designed in compliance with Chile's guidelines on research and confidentiality of information. Results: 95.3% of participants reported knowing the motives for cane use; 7.8% use a cane while walking within home; 45.3% use a cane while walking outdoors; 46.9% use a cane to walk anywhere; and 48.4% said that they do not like to use the cane. The prevalence of falls in the last six months was 73%; 61% of those who have fallen were not using a cane when they fell, and 94% expressed fear of falling. Conclusion: The findings show that a high percentage of older adults is not using a cane, and therefore the ultimate goal of delivering mobility devices is not being achieved. Cane use evaluation and education should be considered as an older adults' health control measure.

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RESUMEN Objetivos Evaluar el efecto de las nanopartículas de ZnO, TiO2 y SiO2 sobre la viabilidad celular y la expresión génica de las interleuquinas 7 y 3 y del factor estimulante de colonias de granulocito - macrófago (GM-CSF) en Mus musculus. Materiales y métodos Se extrajo médula ósea roja de cinco roedores (Balb/c) para el estudio de viabilidad celular mediante la prueba de MTT. Por otro lado, grupos cinco roedores fueron inoculados vía intraperitoneal con dosis de 0,5; 1; 2,5; 5 y 10 mg/kg de nanopartículas de ZnO y SiO2 y de 5; 10; 15; 20 y 25 mg/kg de nanopartículas de TiO2, 30 h después, se obtuvo el ARN a partir de la médula ósea roja para los análisis de expresión génica empleando las técnicas de PCR y RT-PCR cuantitativa. Resultados Las nanopartículas de ZnO y SiO2 redujeron la viabilidad celular de una manera dosis-dependiente en un 37 y 26%, respectivamente, a partir de una dosis de 1 mg/kg. En cuanto al efecto sobre la expresión génica, a las dosis 5 y 10 mg/kg, las nanopartículas de TiO2 redujeron en mayor porcentaje la expresión de las interleuquinas 7 y 3 (55,3 y 70,2% respectivamente), con respecto a la expresión del GM-CSF, el mayor porcentaje de reducción lo produjo las nanopartículas de SiO2 (91%). Las nanopartículas de ZnO redujeron a partir de las dosis de 20 y 25 mg/kg. Conclusiones Las nanopartículas de ZnO, SiO2 y TiO2 alteran la viabilidad celular y la expresión génica en la médula ósea de ratón.

ABSTRACT Objectives To evaluate the effect of ZnO, TiO2 and SiO2 nanoparticles on cell viability and expression of the interleukin 7, interleukin 3, and granulocyte-macrophage colony stimulating factor (GM-CSF) genes in Mus musculus. Material and methods Red bone marrow was extracted from five Balb/c mice for the analysis of cell viability using the MTT test. The mice were divided into two groups of five each: one group was inoculated intraperitoneally with 0.5, 1.0, 2.5, 5.0, and 10 mg/kg of ZnO and SiO2 nanoparticles, respectively, and the other group was inoculated with 5.0, 10.0, 15.0, 20.0, and 25 mg/kg of TiO2 nanoparticles, respectively. Thirty hours later, RNA was extracted from the red bone marrow of the mice in both groups for gene expression analysis using quantitative PCR and RT-PCR. Results ZnO and SiO2 nanoparticles reduced cell viability in a dose-dependent manner by 37% and 26%, respectively, starting at a dose of 1 mg/kg. TiO2 nanoparticles at 5 mg/kg and 10 mg/kg reduced the gene expression of interleukins 7 and 3 by 55.3% and 70.2%, respectively, and SiO2 nanoparticles caused the greatest decrease (91%) in the expression of GM-CSF. ZnO nanoparticles reduced the expression of GM-CSF starting at doses of 20 mg/kg and 25 mg/kg. Conclusions ZnO, SiO2 and TiO2 nanoparticles affect cell viability and gene expression in the mouse bone marrow.

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Introducción: Las infecciones asociadas a ventilación mecánica son causa importante de morbimortalidad en el paciente crítico. La diferenciación entre traqueobronquitis y neumonía no es siempre fácil, y es controvertida. Algunos trabajos describen aumento de mortalidad, mayor estancia en Unidades de Cuidado Intensivo (UCI), mayor requerimiento de ventilación mecánica e incremento de costos en pacientes con traqueobronquitis asociada a ventilador (TAV), sin diferencias significativas en pacientes con neumonía asociada a ventilador (NAV). Estos estudios no describen el comportamiento clínico y epidemiológico de la TAV y la NAV como 2 entidades independientes, por lo que es necesario describirlo. Métodos: Estudio multicéntrico de cohorte prospectiva, de pacientes adultos que desarrollaron TAV o NAV durante su estancia en UCI, entre noviembre de 2013 y octubre de 2014. A cada una de las variables demográficas, clínicas, de laboratorio y de desenlace, como tiempo de ventilación mecánica, estancia hospitalaria y muerte, se le realizó análisis descriptivo; para evaluar las diferencias entre los grupos se utilizó test de chi cuadrado, t de Student o U de Mann Whitney. Resultados: Se incluyó a 143 pacientes, con edad promedio de 55 años, 57% eran hombres, de 6 países en Latinoamérica; 63% con NAV y 37% con TAV. Las comorbilidades más frecuentes fueron cardiovascular (44%) y neurológica (30%); esta última fue más frecuente en TAV (41,5 vs. 23%; p = 0,02). No se encontró diferencia en APACHE II de ingreso. El índice SOFA fue mayor en NAV (8 vs. 5; p = 0,02). No hubo diferencias en el aislamiento microbiológico, ni en los patrones de resistencia bacteriana entre las 2 entidades. Se observó mayor número de complicaciones cardiovasculares y SDRA en pacientes con NAV. No se encontró diferencia entre los 2 grupos en estancia en UCI, los días de ventilación mecánica ni en mortalidad. Conclusiones: La prevalencia de TAV fue mayor a lo descrito hasta ahora en la literatura. No se encontraron diferencias significativas en el aislamiento microbiológico, la resistencia bacteriana ni el esquema antibiótico utilizado en los 2 grupos. Aunque la NAV cursó con mayor proporción de complicaciones médicas asociadas, el hallazgo de una estancia hospitalaria, tiempo de ventilación mecánica y mortalidad similares sustenta la importancia clínica de la TAV.

Introduction: The infections associated with mechanical ventilation are a major cause of morbidity and mortality in critically ill patients. Limited studies report increased mortality and intensive care units (ICU) stays, requirements for mechanical ventilation and higher costs in ventilator-associated tracheobronchitis (TAV) in comparison to patients with ventilator-associated pneumonia (NAV). These studies do not describe the clinical and epidemiological behavior in the same population as independent entities, so it is necessary to describe the epidemiology of patients with TAV and NAV. Methods: Multicenter cross-sectional study of adult patients who developed TAV and/or NAV during their stay in the ICU in 2013 to 2014. A descriptive analysis was performed on each of the variables. For qualitative variables we assessed differences between groups using the Chi-squared test; for continuous variables, we used Student's t test or the Mann Whitney U test. Results: A total of 147 patients from 6 countries in Latin America were included; 63% with NAV and 37% with TAV. The average age was 55 years; 57% male. The most frequent comorbidity was cardiovascular (44%) and neurological (30%), the latter was more frequent in those with TAV (41.5 vs. 23%, P = .02). No differences were found in APACHE II on entry, but the difference appears in the SOFA index (8 vs. 5, P = .02). There were no differences in microbiological isolation, or bacterial resistance patterns between the 2 entities. A greater number of cardiovascular complications and ARDS were observed in patients with NAV. The ICU stay, days on mechanical ventilation and mortality were not different between the 2 groups. Conclusions: The TAV prevalence was higher than heretofore described in the literature. No significant differences were found in the microbiological isolation, bacterial resistance and antibiotic therapy used in the 2 groups, which might suggest that therapeutic approach be similar to that recommended for NAV. No differences were observed in clinical outcomes such as hospital stay, duration of mechanical ventilation and mortality, although NAV was associated with a greater proportion of medical complications.

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The aim of this work was to explore the ability of free arachidonic acid, palmitic acid and the unsaturated fatty acids oleic acid and docosahexaenoic acid to modify calcium homeostasis and mitochondrial function in rat pachytene spermatocytes and round spermatids. In contrast to palmitic acid, unsaturated fatty acids produced significant increases in intracellular calcium concentrations ([Ca2+]i) in both cell types. Increases were fatty acid specific, dose-dependent and different for each cell type. The arachidonic acid effects on [Ca2+]i were higher in spermatids than in spermatocytes and persisted when residual extracellular Ca2+ was chelated by EGTA, indicating that the increase in [Ca2+]i originated from release of intracellular calcium stores. At the concentrations required for these increases, unsaturated fatty acids produced no significant changes in the plasma membrane potential of or non-specific permeability in spermatogenic cells. For the case of arachidonic acid, the [Ca2+]i increases were not caused by its metabolic conversion to eicosanoids or anandamide; thus we attribute this effect to the fatty acid itself. As estimated with fluorescent probes, unsaturated fatty acids did not affect the intracellular pH but were able to induce a progressive decrease in the mitochondrial membrane potential. The association of this decrease with reduced reactive oxygen species (ROS) production strongly suggests that unsaturated fatty acids induced mitochondrial uncoupling. This effect was stronger in spermatids than in spermatocytes. As a late event, arachidonic acid induced caspase 3 activation in a dose-dependent manner both in the absence and presence of external Ca2+. The concurrent but differential effects of unsaturated fatty acids on [Ca2+]i and mitochondrial functions are additional manifestations of the metabolic changes that germ cells undergo during their differentiation.

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BACKGROUND: The present investigation evaluated 4 different solvent compositions for their relative capacity to extract total phenolic and total flavonoid (TF) components of the leaves, trunks, and stems of Bucida buceras L. (Combretaceae), and the stems of Phoradendron californicum (Viscaceae), plus mesquite and oak species endemic to the Southwestern United States, northern Mexico, and tropical regions of Central and South America, as well as to profile the composition of these plant materials and to measure their antioxidant capacity. METHODS: The total phenolic content of plant material used in the present investigation was measured using the Folin-Ciocalteau assay. Total flavonoids were assayed by AlCl3 and 2,4-dinitrophenylhydrazin colorimetry. Nitroblue tetrazolium was utilized for scavenging of superoxide anion, and in vitro antioxidant activity was evaluated using the 2, 2-diphenyl-1-picrylhydrazyl and Ferric Reducing/Antioxidant Power assays. RESULTS: Phytochemical screening of each plant extract evaluated revealed the following major results: (1) No evidence of alkaloids for each of the extraction phases tested was detected in the hexanic, ethanolic, or aqueous phases of Bucida buceras and Phoradendron californicum (oak and mesquite); (2) Analysis of the hexane phase of B. buceras and P. californicum (mesquite) extracts revealed the presence of carotenes, triterpenes/steroids, and lactonic groups; (3) Analysis of the ethanol and aqueous extraction phases for both plants revealed the presence of a diverse range of compounds, including tripterpenes/steroids, lactonics groups, saponins, phenols/tannins, amines and/or amino acids, and flavonoids/anthocyanins; and (4) The highest total phenolic and flavonoid content were observed in P. californicum (oak): 523.886 ± 51.457 µg GAE/mg extract and 409.651 ± 23.091 µg/mg of extract for methanol and aqueous fractions, respectively. The highest flavonoid content was 237.273 ± 21.250 µg PNE/mg extract in the acetone extract of Bucida buceras stems; while the flavonol content (260.685 ± 23.031 µg CE/mg extract) was higher in the ethanol extract of P. californicum (oak). The acetone extract of B. buceras trunk extract showed the highest levels of DPPH radical-scavenging activity (IC50 = 4.136 ± 0.446 µg/mL) and reducing power (4928.392 ± 281.427 µM AAE/mg extract). The highest superoxide radical scavenging activity (IC50) was 55.249 ± 9.829 µg/mL, observed in acetone extracts of B. buceras leaves. CONCLUSIONS: The results of the present investigation demonstrated the effects of extraction solvent on phenolic and flavonoid content yield-and antioxidant activities by Bucida buceras and Phoradendron californicum. The present investigation further revealed that Bucida buceras exhibited optimal antioxidant capacity when acetone was used as extraction solvent; and the highest yield of phenols and flavonoids were obtained from the P. californicum oak, using methanol and aqueous solvents, respectively.

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BACKGROUND: Reactive Oxygen Species (ROS) impair the physiological functions of Retinal Pigment Epithelial (RPE) cells, which are known as one major cause of age-related macular degeneration and retinopathy diseases. The purpose of this study is to explore the cytoprotective effects of the antioxidant Bucida buceras extract in co-treatment with hydrogen peroxide (H2O2) delivery as a single addition or with continuous generation using glucose oxidase (GOx) in ARPE-19 cell cultures. The mechanism of Bucida buceras extract is believed to be associated with their antioxidant capacity to protect cells against oxidative stress. METHODS: A comparative oxidative stress H2O2-induced was performed by addition and enzymatic generation using glucose oxidase on human retinal pigment epithelial cells line. H2O2-induced injury was measured by toxic effects (cell death and apoptotic pathway) and intracellular redox status: glutathione (GSH), antioxidant enzymes (catalase and glutathione peroxidase) and reducing power (FRAP). The retino-protective effect of co-treatment with Bucida buceras extract on H2O2-induced human RPE cell injury was investigated by cell death (MTT assay) and oxidative stress biomarkers (H2O2, GSH, CAT, GPx and FRAP). RESULTS: Bucida buceras L. extract is believed to be associated with the ability to prevent cellular oxidative stress. When added as a pulse, H2O2 is rapidly depleted and the cytotoxicity analyses show that cells can tolerate short exposure to high peroxide doses delivered as a pulse but are susceptible to lower chronic doses. Co-treatment with Bucida buceras was able to protect the cells against H2O2-induced injury. In addition to preventing cell death treatment with antioxidant plant could also reverse the significant decrease in GSH level, catalase activity and reducing power caused by H2O2. CONCLUSION: These findings suggest that Bucida buceras could protect RPE against ocular pathogenesis associated with oxidative stress induced by H2O2-delivered by addition and enzymatic generation.

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O presente trabalho tem por objetivo conhecer as concepções de estudantes ingressantes no ensino médio a respeito de conceitos fundamentais que caracterizam as transformações químicas. Trata-se de um estudo de caso, em que dezessete estudantes de uma instituição pública de ensino propuseram explicações para um problema sobre um processo de combustão. As respostas por eles elaboradas foram categorizadas por meio da análise de conteúdo. Foi evidenciado que os estudantes utilizam distintos modelos para interpretar o que acontece durante uma reação química e que, na maioria das situações, esses modelos constituem obstáculos para a aprendizagem dos conceitos que são objeto de estudo da química. Embora indiquem a não conservação das substâncias como critério para justificar a ocorrência de uma reação química, a não conservação da matéria e da massa estão presentes nas ideias de transmutação, desaparecimento, substituição, entre outras. Além disso, foram explicitadas confusões conceituais no emprego da linguagem científica e na representação da combustão (desenho), de modo que, ressalta-se a importância dos resultados evidenciados nesta investigação para a proposição de ações que busquem qualificar o ensino e da aprendizagem da química na educação básica (AU)

This paper aims understanding students’ conceptions of fundamental concepts that characterize the chemical transformations. Thisis a case study in which seventeen students of the first year in a public high school proposed explanations for a problem about a combustion process. The answers given were categorized by means of content analysis. It was evident thatstudents use different models to interpret what happens during a chemical reaction and that, in most situations, these models constitute barriers that prevent students from learning the concepts that are the object of study of chemistry. Althoughthey mention the loss of substance as a criterion to justify the occurrence of a chemical reaction, the notion of mass and matter loss is present in the ideas of transmutation, disappearance and replacement, among others. Furthermore, conceptual misunderstandings were explicitin the use of scientific language and in the representation of combustion (drawings), so that the study emphasizes the relevance of the results found in this research to propose actions that seek to qualify the teaching and learning processes of chemistry in basic education (AU)

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