ABSTRACT In this work, we present models of massive stars between 15 and 23 M⊙, with enhanced mass loss rates during the red supergiant phase. Our aim is to explore the impact of extreme red supergiant mass-loss on stellar evolution and on their circumstellar medium. We computed a set of numerical experiments, on the evolution of single stars with initial masses of 15, 18, 20 and, 23 M⊙, and solar composition (Z = 0.014), using the numerical stellar code BEC. From these evolutionary models, we obtained time-dependent stellar wind parameters, that were used explicitly as inner boundary conditions in the hydrodynamical code ZEUS-3D, which simulates the gas dynamics in the circumstellar medium (CSM), thus coupling the stellar evolution to the dynamics of the CSM. We found that stars with extreme mass loss in the RSG phase behave as a larger mass stars.

RESUMEN En este trabajo presentamos modelos evolutivos de estrellas en el intervalo de 15 a 23 M⊙, usando un incremento en la tasa de pérdida de masa durante su fase de supergigante roja para explorar el impacto de una fuerte pérdida de masa en la evolución de la estrella y en la dinámica de su medio circunestelar. Calculamos un conjunto de experimentos numéricos simulando la evolución de estrellas aisladas con masas iniciales de 15, 18, 20 y 23 M⊙ y metalicidad solar (Z = 0.014) usando el código estelar BEC. De los modelos evolutivos obtuvimos parámetros característicos del viento estelar dependientes del tiempo para usarlos como condiciones de contorno en el código hidrodinámico explícito ZEUS-3D para simular la evolución del medio circunestelar. Encontramos que las estrellas con altas tasas de pérdida de masa durante la etapa de supergigante roja se comportan como estrellas de mayor masa.

In the present study was evaluated the efficiency of plant extracts from Larrea tridentata extracted with four solvents in vitro inhibition of radial growth of Penicillium polonicum, Aspergillus niger, Rhizopus oryzae y Alternaria tenuissima. Fungi were identified using colonial, morphological taxonomic keys and the corresponding molecular techniques identified species each. A design was randomly applied altogether with 16 treatments in each mold, corresponding to four solvents: dichloromethane, ethanol, methanol and water, with four concentrations: 0, 250, 500 and 750 ppm to Alternaria sp.; 0, 2000, 2500 and 3000 to Aspergillus sp.; 0, 1500, 1750 and 2000 to Penicillium sp. and 0, 150, 200 and 250 to Rhizopus sp. Each treatment had three replicates. Molecular analysis determined the tenuissima specie to Alternaria, niger to Aspergillus, polonicum to Penicillium and oryzae to Rhizopus. About in vitro testing, inhibition of 100% for three of the study were determined fungi: Alternaria tenuissima EtOH extract to 750 ppm; Aspergillus niger with DCM extract and Rhizopus oryzae 3000 ppm from 150 ppm to 250 ppm of the DCM and EtOH extracts respectively. 82% inhibition at 2000 ppm for Penicillium polonicum was presented. It is concluded that despite the differences in susceptibility between the fungal species, Larrea tridentata extracts obtained with ethanol and dichloromethane are effective for the control of postharvest fungi under in vitro study.

En el presente estudio se evaluó la eficiencia de extractos vegetales de Larrea tridentata obtenidos con diclorometano, etanol, metanol y agua, sobre el crecimiento radial in vitro de cuatro hongos fitopatógenos, los cuales primeramente fueron identificados en género y especie empleando claves taxonómicas y técnicas moleculares. Para los bioensayos in vitro se aplicaron diseños completamente al azar con cuatro tratamientos y tres repeticiones en cada hongo, utilizando las concentraciones: 0, 250, 500 y 750 ppm para Alternaria sp.; 0, 2000, 2500 y 3000 para Aspergillus sp.; 0, 1500, 1750 y 2000 para Penicillium sp. y 0, 150, 200 y 250 ppm para Rhizopus sp. Cada tratamiento tuvo tres repeticiones. El análisis molecular determinó la especie tenuissima para Alternaria, niger para Aspergillus, polonicum para Penicillium y oryzae para Rhizopus. En cuanto a las pruebas in vitro, se determinaron inhibiciones del 100% para tres de los hongos en estudio: Alternaria tenuissima con extracto EtOH a 750 ppm; Aspergillus niger con extracto DCM a 3000 ppm y Rhizopus oryzae a partir de 150 ppm y 250 ppm de los extractos DCM y EtOH respectivamente. Se presentó una inhibición del 82% a 2000 ppm para Penicillium polonicum. Se concluye que a pesar de las diferencias en susceptibilidad entre las especies fúngicas, los extractos de Larrea tridentata obtenidos con etanol y dicloromentano son efectivos para el control de los hongos fitopatógenos bajo estudio in vitro.

Our goal is to describe and analyze the use of tissue expanders for reconstruction of craniofacial defects in 3 highly complex centers in the country (Chile). Corresponds to a retrospective study of patients treated at Hospital Militar de Santiago, Clinica Alemana e Instituto de Neurocirugia Asenjo between 2004 and 2012 by defects in the craniofacial area. We collected in a total of 37 patients medical data, demographic data, operation time, volume, number of expanders used, photographic records, complications, volume overexpansion, and a questionnaire regarding patients' satisfaction with the use of tissue expander. Adequate coverage of the defect was obtained in all cases. In 16 patients (43,2 %) using 2 tissue expanders; in 15 (40,5 %) with 1 expander; in 4 (10,8 %) with 3 expanders and in 2 (5,4 %) with 4 expanders. Total treatment time corresponded on average to 70 days, with a percentage of minor complications in 35,1 % patients and major complications in 2,7 % patients. Regarding the applied questionnaire we obtained 94,6 % of positive responses regarding the final result of the surgery; only 54,1 % of the patients would recommend this method of tissue expansion to a third party. In our study, a good final result was achieved with low rate of major complications and a high rate of satisfaction in the outcome of surgery by patients. The administration of the questionnaire is useful for obtaining more objective information regarding the review of this process by patients undergoing this surgery.

El objetivo del presente estudio es describir y analizar el uso de expansores tisulares para reconstrucción de los defectos craneofaciales en 3 centros de alta complejidad del país (Chile). Corresponde a un estudio descriptivo retrospectivo de pacientes tratados en el Departamento de Cirugía Plástica del Hospital Militar de Santiago, Clínica Alemana e Instituto de Neurocirugía Asenjo entre los años 2004 y 2012 por defectos en el área craneofacial. Recopilamos en un total de 37 pacientes los datos médicos, demográficos, de la operación, tiempo, volumen, número de expansores utilizados, registros fotográficos, complicaciones, volumen de sobrexpansión, y un cuestionario de satisfacción de los pacientes en relación al uso del expansor tisular. Se obtuvo cobertura adecuada del defecto en la totalidad de los casos. En 16 pacientes (43,2 %) mediante el uso de 2 expansores tisulares; en 15 (40,5 %) con 1 expansor; en 4 (10,8 %) con 3 expansores y en 2 pacientes (5,4 %) con 4 expansores. El tiempo total de tratamiento en promedio correspondió a 70 días, con un porcentaje de complicaciones menores en un 35,1 % de los casos, y mayores en un 2,7 % . En relación al cuestionario aplicado, obtuvimos un 94,6 % de respuestas positivas respecto al resultado final de la cirugía; sólo un 54,1 % de los pacientes recomendaría este método de expansión tisular a un tercero. En conclusión, nuestro estudio determina que se logró un buen resultado final, con bajo porcentaje de complicaciones mayores y alto porcentaje de satisfacción en el resultado de la cirugía por parte de los pacientes. La aplicación del cuestionario, resulta útil para la obtención de información más objetiva respecto a la opinión sobre este procedimiento por parte de los pacientes.

Introduction: Vitamin B12 deficiency is extremely common in strict vegetarians and their variants. Infants of vegetarian mothers have a higher risk of deficiency and are more prone to its effects. Objective: To report a case in order to warn people about the importance of suspected vitamin B12 deficiency in children of vegetarian mothers. Case report: A 12-month old infant, daughter of a longtime vegetarian woman, who presented neurological and hematological compromise due to vitamin B12 deficiency, is discussed. After a short period of parenteral administration of cyanocobalamin and enteral nutrition, the patient evolved with clinical and laboratory improvement, although she still had residual development delay. Conclusions: Vitamin B12 deficiency is often not suspected by the pediatrician in healthy infants. Clinical manifestations can be nonspecific, such as apathy, food refusal and progressive impairment of psychomotor development. A nutritional anamnesis performed on the mother (with great emphasis on those strict vegetarians) to estimate her reserves in the period prior to, during and after delivery can be critical to detect the risk of this vitamin deficiency in young children.

Introducción: La deficiencia de vitamina B12 es una de las complicaciones del vegetarianismo y sus variantes. Los lactantes de madres vegetarianas tienen mayor riesgo de deficiencia y son más lábiles a sus efectos. Objetivo: Relatar un caso para alertar sobre la importancia de la sospecha de deficiencia de vitamina B12 en hijos de madres con hábito vegetariano. Caso clínico: Se presenta una lactante de 12 meses, hija de una mujer vegetariana de larga data, que se presenta con compromiso neurológico y hematológico por déficit de vitamina B12. Luego de un corto período de administración de cianocobalamina parenteral y apoyo enteral nutricional, evoluciona con una notoria mejoría clínica y de laboratorio, aunque aún presenta retraso del desarrollo residual. Conclusiones: La deficiencia de vitamina B12 no es frecuentemente sospechada por el pediatra en lactantes sanos. Sus manifestaciones clínicas pueden ser tan inespecíficas, como la apatía, el rechazo alimentario y el deterioro progresivo del desarrollo psicomotor. Una anamnesis nutricional breve realizada a la madre (con mayor énfasis en aquellas vegetarianas) para estimar sus reservas en el periodo previo, durante y después del parto pueden ser fundamentales para detectar el riesgo déficit de esta vitamina en el niño pequeño.

A full-thickness chondral defect in the stifle joint of eight mares was treated by perforation of the subchondral bone. In addition, the experimental group received an arthroscopic implant of a tissue-engineered construct. The objective was the arthroscopic evaluation of the quality of the repair tissue, six months after the treatments. The experimental group presented a statistically significant (p = 0.001) improvement in the repair tissue.

Un defecto condral de espesor total en la babilla de ocho yeguas fue tratado con una perforación en el hueso subcondral. Adicionalmente, en el grupo experimental fue implantado artroscópicamente un constructo creado por ingeniería de tejidos. El objetivo fue la evaluación artroscópica de la calidad del tejido de reparación, seis meses después de los tratamientos. El grupo experimental mostró mejoría estadísticamente significativa (p = 0.001) en el tejido de reparación.

Shiga toxin-producing E. coli (STEC) is one of the most important emergent pathogen in foods, being its main reservoir bovine cattle. STEC can cause diarrhea, hemorrhagic colitis and hemolytic-uremic syndrome. The present work have studied the cytotoxic action in human colon of cultures of two STEC strains isolated from faeces of calves with bloody diarrhea. Colonic mucosa was mounted as a diaphragm in a Ussing chamber and incubated with the cultures of pathogenic strains. Net water flow (Jw) decreased and the short-circuit current (Isc) increased significantly (p < 0,01) compared to negative control. Tissues showed an erosion of the mucose, epithelial exfoliation, and presence of pseudo-membranes in the lumen. Mild circulatory lesions were observed in the lamina propia. A moderate neutrophils infiltration was observed in the lumen and into the epithelial cells. Colonic crypts were not disrupted. Both experimental strains caused a similar lesion on colon tissues. This is the first study that shows that cultures of STEC strains isolated from bovine cattle produce cytotoxic effects in vitro in human colon.

Escherichia coli productor de toxina Shiga (STEC) es el patógeno emergente en alimentos de mayor impacto, siendo su principal reservorio el ganado bovino. STEC puede causar diarrea, colitis hemorrágica y síndrome urémico hemolítico. El presente trabajo estudió la acción citotóxica de dos cepas de STEC aisladas de heces de terneros diarreicos en colon humano in vitro. Los fragmentos se montaron como un diafragma en una cámara de Ussing y se incubaron con las cepas patógenas. El flujo neto absortivo de agua (Jw) disminuyó y la corriente de cortocircuito (Isc) aumentó significativamente (P < 0,01) con respecto al control negativo. Los tejidos presentaron erosión de la mucosa, exfoliación del epitelio, y presencia de pseudomembranas en el lumen. A nivel de la lámina propia se observaron lesiones circulatorias leves. Una moderada infiltración de neutrófilos se observó en el lumen y en las células epiteliales. Las criptas colónicas no se vieron afectadas. El grado de lesión fue similar en ambas cepas experimentales. Este es el primer estudio que demuestra que cultivos de cepas de STEC aisladas de ganado bovino producen efectos citotóxicos en colon humano in vitro.

Shiga toxin (Stx)-producing Escherichia coli (STEC) colonizes the large intestine causing a spectrum of disorders, including watery diarrhea, bloody diarrhea (hemorrhagic colitis), and hemolytic-uremic syndrome. It is estimated that hemolytic-uremic syndrome is the most common cause of acute renal failure in infants in Argentina. Stx is a multimeric toxin composed of one A subunit and five B subunits. In this study we demonstrate that the Stx2 B subunit inhibits the water absorption (Jw) across the human and rat colonic mucosa without altering the electrical parameters measured as transepithelial potential difference and short circuit current. The time-course Jw inhibition by 400 ng/ml purified Stx2 B subunit was similar to that obtained using 12 ng/ml Stx2 holotoxin suggesting that both, A and B subunits of Stx2 contributed to inhibit the Jw. Moreover, non-hemorrhagic fluid accumulation was observed in rat colon loops after 16 h of treatment with 3 and 30 ng/ml Stx2 B subunit. These changes indicate that Stx2 B subunit induces fluid accumulation independently of A subunit activity by altering the usual balance of intestinal absorption and secretion toward net secretion. In conclusion, our results suggest that the Stx2 B subunit, which is non-toxic for Vero cells, may contribute to the watery diarrhea observed in STEC infection. Further studies will be necessary to determine whether the toxicity of Stx2 B subunit may have pathogenic consequences when it is used as a component in an acellular STEC vaccine or as a vector in cancer vaccines.

Adenylyl cyclase (AC) isoforms catalyze the synthesis of 3',5'-cyclic AMP from ATP. These isoforms are critically involved in the regulation of gene transcription, metabolism, and ion channel activity among others. Nitric oxide (NO) is a gaseous product whose synthesis from L-arginine is catalyzed by the enzyme NO synthase. It has been well established that NO activates the enzyme guanylyl cyclase, but little has been reported on the effects of NO on other important second messengers, such as AC. In the present study, the effects of sodium nitroprusside (SNP), a nitric oxide-releasing compound, on COS-7 cells transfected with plasmids containing AC types I, II, V and VI were evaluated. Total inhibition (~98.5%) of cAMP production was observed in COS-7 cells transfected with the AC I isoform and previously treated with SNP (10 mM) for 30 min, when stimulated with ionomycin. A high inhibition (~76%) of cAMP production was also observed in COS-7 cells transfected with the AC VI isoform and previously treated with SNP (10 mM) for 30 min, when stimulated with forskolin. No effect on cAMP production was observed in cells transfected with AC isoforms II and V.

Water channels or aquaporins (AQPs) have been identified in a large variety of tissues. Nevertheless, their role in the human gastrointestinal tract, where their action is essential for the reabsorption and secretion of water and electrolytes, is still unclear. The purpose of the present study was to investigate the structure and function of water channels expressed in the human colon. A cDNA fragment of about 420 bp with a 98% identity to human AQP3 was amplified from human stomach, small intestine and colon by reverse transcription polymerase chain reaction (RT-PCR) and a transcript of 2.2 kb was expressed more abundantly in colon than in jejunum, ileum and stomach as indicated by Northern blots. Expression of mRNA from the colon of adults and children but not from other gastrointestinal regions in Xenopus oocytes enhanced the osmotic water permeability, and the urea and glycerol transport in a manner sensitive to an antisense AQP3 oligonucleotide, indicating the presence of functional AQP3. Immunocytochemistry and immunofluorescence studies in human colon revealed that the AQP3 protein is restricted to the villus epithelial cells. The immunostaining within these cells was more intense in the apical than in the basolateral membranes. The presence of AQP3 in villus epithelial cells suggests that AQP3 is implicated in water absorption across human colonic surface cells.