Validation of extracellular ligand-receptor interactions by Flow-TriCEPS.

OBJECTIVE: The advent of ligand-based receptor capture methodologies, allows the identification of unknown receptor candidates for orphan extracellular ligands. However, further target validation can be tedious, laborious and time-consuming. Here, we present a methodology that provides a fast and cost-efficient alternative for candidate target verification on living cells. RESULTS: In the described methodology a ligand of interest (e.g. transferrin, epidermal growth factor or insulin) was conjugated to a linker (TriCEPS) that carries a biotin. To confirm ligand/receptor interactions, the ligand-TriCEPS conjugates were first added onto living cells and cells were subsequently labeled with a streptavidin-fluorophore and analyzed by flow cytometry (thus referred as Flow-TriCEPS). Flow-TriCEPS was also used to validate identified receptor candidates when combined with a siRNA knock down approach (i.e. reduction of expression levels). This approach is versatile as it can be applied for different classes of ligands (proteins, peptides, antibodies) and different cell lines. Moreover, the method is time-efficient since it takes advantage of the large variety of commercially available (and certified) siRNAs.

Stop Saying That It Is Wrong! Psychophysiological, Cognitive, and Metacognitive Markers of Children's Sensitivity to Punishment.

Neurodevelopmental evidence suggests that children's main decision-making strategy is to avoid options likely to induce punishment. However, the cognitive and affective factors contributing to children's avoidance to high punishment frequency remain unknown. The present study explored psychophysiological, cognitive, and metacognitive processes associated with sensitivity to punishment frequency. We evaluated 54 participants (between 8 and 15 years old) with a modified Iowa Gambling Task for children (IGT-C) which included options with varying long-term profit and punishment frequencies. Skin conductance responses (SCRs) were recorded during this task. Additionally, we assessed IGT-C metacognitive knowledge, fluid intelligence, and executive functions. Participants exhibited behavioral avoidance and high anticipatory SCRs to options with high frequency of punishment. Moreover, age, IGT-C metacognitive knowledge, and inhibitory control were associated with individual differences in sensitivity to punishment frequency. Our results suggest that children's preference for infrequently punished decisions is partially explained by psychophysiological signals as well as task complexity and development of cognitive control.

Resultados de un programa de alfabetización temprana: Desempeño en lectura en niños de sectores en desventaja socioeconómica / Result of an early literacy intervention program: Reading skills in children with socio-economic disadvantages

El objetivo del trabajo que se informa fue contribuir al conocimiento del proceso de alfabetización temprana en español en sectores en desventaja socioeconómica y cultural y analizar los resultados de un estudio destinado al desarrollo de habilidades relativas a la lectura de palabras y textos en niños de 4 a 7 años de edad. Se comparó el desempeño de dos grupos de niños (experimental y control) que concurrían a escuelas públicas de la Provincia de Buenos Aires (Argentina) y que habían sido homologados en todas las variables analizadas. Uno de ellos recibió intervención específica en alfabetización temprana durante 2 años. Las evaluaciones se realizaron antes, durante y a mediano plazo, una vez finalizada la intervención. Sobre los datos obtenidos se calcularon estadísticos descriptivos (medias, desvíos estándar y porcentajes de aciertos) y estadísticos inferenciales (prueba t y de diferencia de proporciones). Asimismo, se realizaron análisis cualitativos de los tipos de errores cometidos y de las estrategias utilizadas para la lectura de palabras (pre-analítica,analítica incompleta inicial e intermedia y alfabética consolidada) y lectura de texto (lectura silabeante sin y con recodificación, fluida y expresiva). Los resultados encontrados muestran mejoras evidentes en la lectura de palabras largas y pseudopalabras, con una diferencia al final de la intervención de hasta un 33% entre ambos grupos, a favor del grupo experimental, cuyos niños utilizan mayor porcentaje de estrategias analíticas. En la lectura de textos aparece una diferencia similar (27%) a favor del grupo experimental, entre los niños que pueden leer fluidamente un texto corto. Esto prepara los cimientos para un adecuado progreso en la comprensión lectora y demuestra el alto impacto de la intervención realizada.

The purpose of this study is to contribute to the understanding of the process of early literacy in Spanish in children with cultural and socio-economic disadvantages. Likewise, it aims at showing the results of a study about reading skills - specifically the reading of words and texts by 4 to 7 year-old children. The study was conducted following research models of Cognitive Psychology and was carried out by comparing the performance of two groups of children, the test group and the control group. These children attended public schools in the Province of Buenos Aires (Argentina) and they were treated as equivalents in all of the analyzed variables. One of the groups received specific early literacy intervention for two years. The assessments were made before, during and midway after finishing the intervention. The reading of words and pseudo words as well as reading and reading comprehension were evaluated. Gough and Juel (1989) propose a simple reading model that states that reading comprehension is the result of the multiplication of decoding and oral language comprehension [RC (reading comprehension) = D*LC (decoding multiplied by language comprehension)]. The multiplying nature of this relationship means that both factors, D and LC, are necessary for comprehension purposes but none of them are sufficient by themselves (Gough, Juel, & Griffith, 1992; Hoover & Gough, 1990). By analyzing the correlation between RC and each of the two factors, it is clearly shown that decoding is the most important step at the beginning of the learning process [r (RC*D) = .61 and r (RC*LC) =.39] and that the values are later reversed at the beginning of secondary school [r (RC*LC) = .68 and r (RC*D) = .39] (Alegría, 2006). Therefore, the differences in the reading comprehension process during the first years of schooling could be due to differences in fluency in reading. At the same time, the automatic word recognition theory (La Berge & Samuels, 1974) provides a strong explanation about the importance of fluency in reading. If the word recognition process is not fluent enough, a lot of energy is placed on paying attention, causing comprehension to be impaired. Taking the above information into account, one of the objectives of the implemented early intervention program has been to promote automatic decoding so that a minimum of other attention resources would be needed. In order to achieve this, it was necessary to develop phonological skills, knowledege of grapheme - phoneme correspondence, as well as the fast ensemble of phonemes. From the data gathered descriptive statistics (means, standard deviations, and achievement percentages) and inferential statistics (t test and percentage difference tests) were obtained. Likewise, a qualitative analysis of the types of mistakes made and the strategies used for word reading (pre-analytical, initial incomplete analytical and intermediate, and consolidated literacy) as well as the different categories in oral text reading (syllabification reading with and without recoding, fluent and expressive) was made. The results of the study show significant improvement in the reading of long words and pseudo words with a 33 % difference between the two groups, in favor of the experimental group, at the end of the intervention. The children from this group use a greater percentage of analytical strategies, which helps them read new words. Regarding text reading, there is a 27% difference among the children who can read a short text fluently in the test group and the ones who cannot do it in the control group. This finding has helped established a good foundation for adequate improvement in reading comprehension skills and shows the high impact the intervention has had on these children.

Estrategias de intervención en desarrollo psicológico y desnutrición infantil primaria / Intervention strategies in psychological development and child malnutrition primary

El retraso en el desarrollo psicológico infantil en poblaciones carecientes se multiplica tres veces en relación con las cifras esperadas para la población general. En la Unidad de Rehabilitación Nutricional (URN) se desarrolla un progrma permanente de asistencia integral a la población de alto riesgo social con desnutricón de causa primaria. El objetivo desde el área psicológica es intervenir tempranamente para prevenir déficit en el el desarrolo psicològico. El propósito de este trabajo es estudiar la correlaciones existentes entre diferenctes variables como: escolaridad materna, actitud de los padres, desarrollo de los niños y evolución en el tratamiento, para lao cual se tomo una casuítitica de 42 familias y sus niños de 0 a 5 años ingresados al progrma de julio a diciembre de 1995. Se utilizaron como instrumentros para la evaluación una entrevista semiestructurada con los padres y la Escala de Evaluación del Desarrollo Psicomotor (EEDP) para 0-2 años y el Test de Desarrollo Psicomotor (TEPSI) para 2-5 años. Se implementaron estrategias de promoción del desarrollo personalizadas y se constato una evolución favorable en el 50 por ciento de los casos. Una de las conclusiones mas importantes es que resulta imprescindible un cambio de actitud de la madre en cuanto a la imporancia concedida al desarroollo psicológico y la relación de éste con el futuro del niño.