Resumen: Los estudios a escala de paisaje brindan una visión integrada de la realidad al considerar los componentes naturales y culturales de la misma en conjunto. A través de las unidades de paisaje se pueden identificar áreas homogéneas partiendo de los elementos que componen el paisaje en su integridad. El trabajo propone determinar y caracterizar las unidades de paisaje (UP) que conforman la Cuenca Inferior del Río Chubut, y describir su configuración histórico-ambiental en el período 1865 a la actualidad. La información se obtuvo a través del reconocimiento del territorio en un Sistema de Información Geográfico superponiendo capas hidrológicas, geológicas, edafológicas, entre otras, y por análisis bibliográfico y cartográfico acerca del asentamiento de la población en el período estudiado. Se delimitaron tres UP: Valle Inferior del Río Chubut, Terrazas y Mesetas, y Monte. La superficie total de la CIRCh es 570.768 ha, y cada UP ocupa un área de 78.600 ha, 99.589 ha, y 392.579 ha respectivamente, es decir, 13,77%, 17,44% y 68,78%. Se espera que este estudio constituya un insumo para caracterizar la evolución del uso del suelo y la detección de problemáticas ambientales vinculadas a cada UP.

Abstract: Landscape ecology studies provide an integrated approach of reality by considering both its natural and cultural components together. Through landscape units, homogeneous areas can be identified starting from the elements that configure the landscape as a whole. The work proposes to determine and characterize the landscape units (LU) that conform the Lower Basin of the Chubut River, and describe their historical-environmental configuration in the period 1865 to the present. The information was obtained through the recognition of the territory in a Geographic Information System superimposing hydrological, geological, edaphological layers, among others, and by bibliographic and cartographic analysis about the settlement of the population in the period studied. Three LU were delimited: the Lower Valley of the Chubut River, the Terraces and Plateaus, and the Mount. The total area of the CIRCh is 570.768 ha, and each LU occupies an area of 78.600 ha, 99.589 ha, and 392.579 ha respectively, meaning 13.77%, 17.44% and 68.78%. This study is expected to constitute an input to characterize the evolution of land use and the detection of environmental problems related to each LU.

O uso de bisfenol-A (BPA) ao nivel da industria global foi aumentando nos ultimos anos, e foram os mercados emergentes que deram impulso a essa demanda crescente. As aplicacoes de BPA na industria de alimentos e bebidas representam apenas 3 a 4% do consumo global de policarbonato, mas seu uso esta sendo reexaminado visto que varios trabalhos cientificos indicando a existencia de uma relacao direta entre o BPA e os efeitos adversos na saude foram conhecidos. A contaminacao dos alimentos e bebidas e produzida pela migracao de BPA das embalagens que os contem (alimentos enlatados, vinhos, etc.) e e a principal fonte de exposicao em humanos. Para avaliar esta exposicao, foi desenvolvido e avaliado um metodo analitico por cromatografia gasosa acoplada a espectrometria de massas para a quantificacao do BPA total na urina de gestantes atendidas no Hospital Italiano de Buenos Aires em 2013, com um limite de quantificacao de 2,0 ng/mL e um limite de deteccao de 0,8 ng/mL. Das 149 amostras de urina analisadas, 66,4% foram quantificaveis, com uma mediana de BPA total de 4,8 ng/mL (4,3 ng/mg de creatinina) e a media geometrica de 4,8 ng/mL (4,7 ng/mg de creatinina).

The use of bisphenol-A (BPA) at the level of the global industry has been increasing in recent years, with emerging markets being the drivers of this growing demand. BPA applications in the food and beverage industry represent only 3 to 4% of the global consumption of polycarbonate, but its use is being reexamined because several scientific works were reported indicating the existence of a direct relationship between BPA and adverse effects on health. The contamination of food and beverages is produced by the migration of BPA from the containers that hold them (canned foods, wines, etc.) and it is the main source of exposure in humans. To evaluate this exposure, an analytical method was developed by gas chromatography coupled to mass spectrometry for the quantification of total BPA in urine of pregnant women treated at the Hospital Italiano de Buenos Aires in 2013, with a limit of quantification of 2.0 ng/mL and of detection of 0.8 ng/mL. Of the 149 urine samples analyzed, 66.4% were quantifiable, with a median total BPA of 4.8 ng/mL (4.3 ng/mg creatinine) and a geometric mean of 4.8 ng/mL (4.7 ng/mg creatinine).

El uso de bisfenol-A (BPA) a nivel de la industria global se ha venido incrementando en los ultimos anos, y fueron los mercados emergentes los impulsores de esta demanda creciente. Las aplicaciones de BPA en la industria de los alimentos y bebidas representan solo del 3 al 4% del consumo global de policarbonato, pero su uso esta siendo reexaminado debido a que se conocieron varios trabajos cientificos que indican la existencia de una relacion directa entre el BPA y los efectos adversos para la salud. La contaminacion de los alimentos y bebidas se produce por migracion del BPA desde los envases que los contienen (alimentos enlatados, vinos, etc.), y es la principal fuente de exposicion en el humano. Para evaluar dicha exposicion se desarrollo y valido un metodo analitico por cromatografia gaseosa acoplada a espectrometria de masa para la cuantificacion de BPA total en orina de mujeres embarazadas atendidas en el Hospital Italiano de Buenos Aires en el ano 2013, con un limite de cuantificacion de 2,0 ng/mL y un limite de deteccion de 0,8 ng/mL. De las 149 muestras de orina analizadas, el 66,4% fueron cuantificables, con la mediana de BPA total de 4,8 ng/mL (4,3 ng/mg de creatinina) y la media geometrica de 4,8 ng/mL (4,7 ng/mg de creatinina).

Abstract Pancreatic lipase is a key enzyme in lipid metabolism. Flavonoids are bioactive compounds obtained from vegetables with big relevance, due to their intrinsic interaction with digestive enzymes. Pancreatic lipase activity was evaluated in the presence of flavonoids, through UV-Vis spectroscopy. All tested flavonoids showed a mixed-type inhibition, except catechin, which showed a uncompetitive inhibition. The best inhibitor was quercetin followed by rutin > luteolin > catechin > hesperetin, with IC50 values of 10.30, 13.50, 14.70, 28.50 and 30.50 µM, respectively. The flavonoids inhibitory capacity was related to structural properties shared between the different flavonoids, such as the hydroxylation at C5, C7 (ring A), C2’ and C3’ (ring B), and the double bond between C2 and C3 (ring C). The inhibition results are in agreement with the extrinsic fluorescence analysis. Molecular docking studies indicated that the interaction between pancreatic lipase and flavonoids was mainly through hydrophobic interactions (pi-stacking). The interactions of all flavonoids, except rutin, occurred at the same enzyme site (subsite 1). Instauration between C2 and C3 was decisive for the arrangement of flavonoids with the enzyme, mainly due to pi-stacking interactions.

Resumen Lipasa pancreática es una enzima clave en el metabolismo de lípidos. Los flavonoides son compuestos bioactivos de gran relevancia debido a sus interacciones con enzimas digestivas. Se evaluó la actividad de lipasa pancreática en presencia de flavonoides. Mediante espectroscopía UV Visible se determinó que el mejor inhibidor fue quercetina, seguido de rutina > luteolina > catequina > hesperetina, con valores de IC50 de 10.30, 13.50, 14.70, 28.50 y 30.50 µM, respectivamente. Todos los flavonoides mostraron una inhibición mixta, excepto catequina que mostró una inhibición acompetitiva. La capacidad inhibitoria de los flavonoides se relacionó con propiedades estructurales compartidas entre los distintos flavonoides, como la hidroxilación en las posiciones C5, C7 (anillo A), C2’ y C3’ (anillo B), y el doble enlace entre C2 y C3 (anillo C). Los resultados de inhibición coincidieron con el análisis de la fluorescencia extrínseca. Los estudios de docking molecular indicaron que la interacción entre lipasa pancreática y los flavonoides fue principalmente mediante interacciones hidrofóbicas (pi-stacking). Las interacciones de todos los flavonoides, excepto rutina, se dieron en el mismo sitio (subsitio 1) de la enzima. La insaturación entre C2 y C3 fue determinante para el acomodo de los flavonoides con la enzima, principalmente por interacciones de pi-stacking.

ABSTRACT Vitamin D is a hormone that plays a role in the regulation of numerous genes involved in cell proliferation and maturation. The objective of this work was to determine the prevalence of inadequate values of this vitamin in healthy young people of the city of Asunción and to identify the possible risk factors associated with it. Descriptive observational study based on clinical-epidemiological data and in the determination of 25-hydroxyvitamin D (25-OH vitamin D) by the chemiluminescence method (CMIA). It was considered appropriate values ≥30 ng/dl, inappropriate below this range and deficient <20 ng/dl. Statistical analyzes were carried out with the R-project program. To establish the association, bivariate and multivariate logistic regression was used. We included 817 university students with an average age of 21 years. The average value of the vitamin D concentration was 25 ± 8 ng/dl, ranging from 64.3 to 2.4 ng/dl. Inadequate vitamin D values were found in 75.5% of the participants. Vitamin D deficiency was significantly (p <0.006) more frequent in women, overweight people (p <0.03), lack of sun exposure (p = 0.001) and sedentary lifestyle (p = 0.0001). This study confirms the high prevalence of inadequate vitamin D values in our country and allows us to define a very high risk profile for sedentary and overweight young women, which justifies special attention from physicians and institutions responsible for public health in our country.

RESUMEN La vitamina D es una hormona cumple una función en la regulación de numerosos genes que participan en la proliferación y maduración celular. El objetivo de este trabajo fue determinar la prevalencia de valores inadecuados de esta vitamina en jóvenes sanos de Asunción e identificar los posibles factores de riesgo asociados. Estudio observacional descriptivo basado en datos clínico-epidemiológicos y en la determinación de la 25-hidroxivitamina D (25-OH vitamina D) por el método de quimioluminiscencia (CMIA). Se consideró valor adecuado ≥30 ng/dl, inadecuado por debajo de este rango y deficiente ≤20 ng/dl. El análisis estadístico se realizó con el programa R-proyect. Para establecer factores de riesgo para tener deficiencia de vitamina D se utilizó regresión logística bi y multivariante. Se incluyeron 817 jóvenes universitarios de edad promedio 21 años. La concentración de vitamina D tuvo una media de 25 ± 8 ng/dl, oscilando entre 64,3 y 2,4 ng/dl. El 75,5% de los participantes tenían valores inadecuados de vitamina D. La deficiencia de vitamina D fue significativamente (p = 0,006) más frecuente en mujeres, personas con sobrepeso (p = 0,03), con falta de exposición al sol (p = 0,001) y con sedentarismo (p = 0,0001). Este estudio confirma la elevada prevalencia de valores inadecuados de vitamina D en nuestro país y permite definir un perfil de muy alto riesgo para las jóvenes sedentarias y con sobrepeso, lo que justifica una atención especial de parte de los médicos y las instituciones responsables de la salud pública en nuestro país.

A prospective study was conducted in four tertiary hospitals in Argentina and Mexico in order to describe the occurrence of Clostridium difficileinfection (CDI) in these settings. The objective was to evaluate the incidence of CDI in at-risk populations in Argentina (one center) and Mexico (three centers) and to further explore potential study sites for vaccine development in this region. A prospective, descriptive, CDI surveillance study was conducted among hospitalized patients aged ≥40 years who had received ≥48 h of antibiotic treatment. Stool samples were collected from those with diarrhea within 30 days after starting antibiotics and analyzed for toxins A and B by ELISA, and positive samples were further tested by toxinogenic culture and restriction endonuclease analysis type assay. Overall, 466 patients were enrolled (193 in Argentina and 273 in Mexico) of whom 414 completed the follow-up. Of these, 15/414 (3.6%) experienced CDI episodes occurring on average 18.1 days after admission to hospital and 15.9 days after the end of antibiotics treatment. The incidence rate of CDI was 3.1 (95% CI 1.7-5.2) per 1000 patient-days during hospitalization, and 1.1 (95% CI 0.6-1.8) per 1000 patient-days during the 30-day follow-up period. This study highlighted the need for further evaluation of the burden of CDI in both countries, including the cases occurring after discharge from hospital.