Estudio de asociación entre genotipo de DAT1 y transtorno por déficit de atención / hiperactividad

Introducción: El TDAH tiene un componente genético importante; el gen de transportador de Dopamina (DAT1) se ha asociado con susceptibilidad al TDAH y con sus endofenotipos. El VNTR de 40pb en la región 3’UTR aumenta la expresión del DAT1. En Colombia no hay ningún estudio previo que indique evidencia de la asociación genética entre TDAH y el gen DAT1. Objetivo: Determinar asociación entre el VNTR del DAT1 y el fenotipo y/o endofenotipos del TDAH. Métodos: Se seleccionaron 73 pacientes con TDAH y 75 controles, se valoró en los casos inteligencia y funciones ejecutivas. Mediante (PCR) se amplificó el VNTR DAT1. Se establecieron estadísticos genético poblacionales, análisis de asociación y de regresión logística entre las pruebas neuropsicológicas y genotipo. Resultado: El polimorfismo del DAT1 no mostró asociación con TDAH, ni con alteraciones en las funciones ejecutivas. El genotipo 10/10 del VNTR DAT1 se encontró asociado con el índice de velocidad de procesamiento (p <0,05). En el subgrupo hiperactividad hubo asociación con algunas subpruebas de flexibilidad cognitiva, número de respuestas correctas, total de errores, número de respuestas perseverativas (p ≤ 0.01). En el subgrupo mixto se asoció con índice de comprensión verbal (p <0,05). Conclusiones: No hubo asociación entre el polimorfismo VNTR (DAT1) y el fenotipo de TDAH. Se encontraron asociaciones entre genotipo y algunos test de flexibilidad cognitiva e índice de comprensión verbal. Se establecieron los estadísticos genético poblacionales de este polimorfismo para la población analizada, el cual corresponde al primer reporte de una muestra de nuestro país.

Genetic basis of Sjögren's syndrome. How strong is the evidence?

Sjögren's syndrome (SS) is a late-onset chronic autoimmune disease (AID) affecting the exocrine glands, mainly the salivary and lachrymal. Genetic studies on twins with primary SS have not been performed, and only a few case reports describing twins have been published. The prevalence of primary SS in siblings has been estimated to be 0.09% while the reported general prevalence of the disease is approximately 0.1%. The observed aggregation of AIDs in families of patients with primary SS is nevertheless supportive for a genetic component in its etiology. In the absence of chromosomal regions identified by linkage studies, research has focused on candidate gene approaches (by biological plausibility) rather than on positional approaches. Ancestral haplotype 8.1 as well as TNF, IL10 and SSA1 loci have been consistently associated with the disease although they are not specific for SS. In this review, the genetic component of SS is discussed on the basis of three known observations: (a) age at onset and sex-dependent presentation, (b) familial clustering of the disease, and (c) dissection of the genetic component. Since there is no strong evidence for a specific genetic component in SS, a large international and collaborative study would be suitable to assess the genetics of this disorder.

Prevalencia de enfermedad de Fabry en pacientes en lista de trasplante y posttrasplante renal en fundación cardioinfantil Bogotá

Introducción: La Enfermedad de Fabry (EF), es una enfermedad multisistémica de almacenamiento lisosomal ligada al cromosoma X que afecta principalmente a hombres, pero también puede causar significativa morbilidad en las mujeres heterocigotas (1–5). La deficiencia de la enzyma α-galactosidaseA (α-Gal A,) provoca acumulación de glicosfingolipidos que afectan diferentes tipos celulares entre ellos el endotelio vascular en vasos de pequeño calibre, células epiteliales y Músculo liso en el sistema cardiovascular (cardiomiocitos), sistema nervioso y células epiteliales tubulares del riñón (6,7). Complicaciones como la falla renal es la causa de muerte más frecuente en la EF (7,8). La incidencia se ha calculado en 1 de cada 117.000 nacidos vivos. (9). Objetivos: Determinar la prevalencia de la Enfermedad de Fabry en pacientes con Insuficiencia renal terminal que se encuentren en lista de trasplante y Post-trasplante Renal en Fundación Cardioinfantil Bogotá. Materiales y Métodos: Se realizó un estudio observacional en donde se evaluó la prevalencia de la EF en todos los sujetos mayores de 18 años que se encuentren en lista de trasplante y post-trasplante renal. Resultados: La prevalencia de Enfermedad de Fabry en 98 pacientes con enfermedad renal crónica fue de 7.1% para la muestra general y 12.9% para la muestra con etiología idiopática Conclusiones: La Enfermedad de Fabry es una importante casusa de Enfermedad Renal Crónica Terminal principalmente en el grupo de etiología idiopática. Palabras Clave: Enfermedad de Fabry (FA)

O Binómio «Esquerda/Direita» no Portugal pós-25 de Abril

A esquerda e a direita estão, passados 35 anos, diferentes do que eram, mas iguais na clivagem que as distingue. PCP e CDS/PP alargaram até o grau de polarização, PS e PSD tornaram-se amiúde irmãos siameses que o eleitorado premeia ou penaliza ciclicamente, mas aos quais concede, desde 1975, o seu voto de confiança. na verdade, desde então o PCP está sozinho à esquerda e o CDS/PP à direita, aguardando sempre que um dos partidos chamados a formar governo (PS ou PSD) necessite de uma coligação.

Fifty Years After Angicos : Paulo Freire, Popular Education and the Struggle for a Better World that is Possible

The main thesis of this paper is that Freire’s original experience in Angicos anticipated a grand design for social transformation of educational systems. As such it brought together two key concepts that formulated the basis of his educational system: popular culture as an counter-hegemonic project and popular education, more particularly what was later called citizen schools or public popular education as keystone of his new educational system. I use the term Paulo Freire System to show that his original attempts were not only to challenge pedagogical the prevailing banking education system that was so pervasive in Brazil and Latin American at the time. In challenging the hegemony of banking education, its narrative, theoretical foundations, epistemology and methodology, Freire and his team sought to create a new system that could replace the old one. They saw banking education not only as obsolete in terms of modernization of systems but also oppressive in gnoseological, epistemological and political terms. In the conclusion of this paper I will discuss the twins obsessions of Freire, already present in the Angicos experience and that will stay with him throughout his life: the relationship between democracy, citizenship and education, and education as a postcolonial ethical act of social transformation. I would like to emphasize therefore that the Paulo Freire system, as conceived in the Angicos experience and its aftermath was a much larger and comprehensive system that originally considered, even by his critics.

Comparing correlations of continuous observations from two independent populations using a sequential approach

A sequential study design generally makes more efficient use of available information than a fixed sample counterpart of equal power. This feature is gradually being exploited by researchers in genetic and epidemiological investigations that utilize banked biological resources and in studies where time, cost and ethics are prominent considerations. Recent work in this area has focussed on the sequential analysis of matched case-control studies with a dichotomous trait. In this paper, we extend the sequential approach to a comparison of the associations within two independent groups of paired continuous observations. Such a comparison is particularly relevant in familial studies of phenotypic correlation using twins. We develop a sequential twin method based on the intraclass correlation and show that use of sequential methodology can lead to a substantial reduction in the number of observations without compromising the study error rates. Additionally, our approach permits straightforward allowance for other explanatory factors in the analysis. We illustrate our method in a sequential heritability study of dysplasia that allows for the effect of body mass index and compares monozygotes with pairs of singleton sisters. Copyright (c) 2006 John Wiley & Sons, Ltd.

Longitudinal investigation of the faecal microbiota of healthy full-term infants using fluorescence in situ hybridization and denaturing gradient gel electrophoresis.

From birth onwards, the gastrointestinal (GI) tract of infants progressively acquires a complex range of micro-organisms. It is thought that by 2 years of age the GI microbial population has stabilized. Within the developmental period of the infant GI microbiota, weaning is considered to be most critical, as the infant switches from a milk-based diet (breast and/or formula) to a variety of food components. Longitudinal analysis of the biological succession of the infant GI/faecal microbiota is lacking. In this study, faecal samples were obtained regularly from 14 infants from 1 month to 18 months of age. Seven of the infants (including a set of twins) were exclusively breast-fed and seven were exclusively formula-fed prior to weaning, with 175 and 154 faecal samples, respectively, obtained from each group. Diversity and dynamics of the infant faecal microbiota were analysed by using fluorescence in situ hybridization and denaturing gradient gel electrophoresis. Overall, the data demonstrated large inter- and intra-individual differences in the faecal microbiological profiles during the study period. However, the infant faecal microbiota merged with time towards a climax community within and between feeding groups. Data from the twins showed the highest degree of similarity both quantitatively and qualitatively. Inter-individual variation was evident within the infant faecal microbiota and its development, even within exclusively formula-fed infants receiving the same diet. These data can be of help to future clinical trials (e.g. targeted weaning products) to organize protocols and obtain a more accurate outline of the changes and dynamics of the infant GI microbiota.

A simple syllogism-solving test: empirical findings and implications for g research

It has been reported that the ability to solve syllogisms is highly g-loaded. In the present study, using a self-administered shortened version of a syllogism-solving test, the BAROCO Short, we examined whether robust findings generated by previous research regarding IQ scores were also applicable to BAROCO Short scores. Five syllogism-solving problems were included in a questionnaire as part of a postal survey conducted by the Keio Twin Research Center. Data were collected from 487 pairs of twins (1021 individuals) who were Japanese junior high or high school students (ages 13–18) and from 536 mothers and 431 fathers. Four findings related to IQ were replicated: 1) The mean level increased gradually during adolescence, stayed unchanged from the 30s to the early 50s, and subsequently declined after the late 50s. 2) The scores for both children and parents were predicted by the socioeconomic status of the family. 3) The genetic effect increased, although the shared environmental effect decreased during progression from adolescence to adulthood. 4) Children's scores were genetically correlated with school achievement. These findings further substantiate the close association between syllogistic reasoning ability and g.

Interaction between allelic variations in vitamin D receptor and retinoid X receptor genes on metabolic traits

BACKGROUND: Low vitamin D status has been shown to be a risk factor for several metabolic traits such as obesity, diabetes and cardiovascular disease. The biological actions of 1, 25-dihydroxyvitamin D, are mediated through the vitamin D receptor (VDR), which heterodimerizes with retinoid X receptor, gamma (RXRG). Hence, we examined the potential interactions between the tagging polymorphisms in the VDR (22 tag SNPs) and RXRG (23 tag SNPs) genes on metabolic outcomes such as body mass index, waist circumference, waist-hip ratio (WHR), high- and low-density lipoprotein (LDL) cholesterols, serum triglycerides, systolic and diastolic blood pressures and glycated haemoglobin in the 1958 British Birth Cohort (1958BC, up to n = 5,231). We used Multifactor- dimensionality reduction (MDR) program as a non-parametric test to examine for potential interactions between the VDR and RXRG gene polymorphisms in the 1958BC. We used the data from Northern Finland Birth Cohort 1966 (NFBC66, up to n = 5,316) and Twins UK (up to n = 3,943) to replicate our initial findings from 1958BC. RESULTS: After Bonferroni correction, the joint-likelihood ratio test suggested interactions on serum triglycerides (4 SNP - SNP pairs), LDL cholesterol (2 SNP - SNP pairs) and WHR (1 SNP - SNP pair) in the 1958BC. MDR permutation model testing analysis showed one two-way and one three-way interaction to be statistically significant on serum triglycerides in the 1958BC. In meta-analysis of results from two replication cohorts (NFBC66 and Twins UK, total n = 8,183), none of the interactions remained after correction for multiple testing (Pinteraction >0.17). CONCLUSIONS: Our results did not provide strong evidence for interactions between allelic variations in VDR and RXRG genes on metabolic outcomes; however, further replication studies on large samples are needed to confirm our findings.

A genome-wide test of the differential susceptibility hypothesis reveals a genetic predictor of differential response to psychological treatments for child anxiety disorders

Background: The differential susceptibly hypothesis suggests that certain genetic variants moderate the effects of both negative and positive environments on mental health and may therefore be important predictors of response to psychological treatments. Nevertheless, the identification of such variants has so far been limited to preselected candidate genes. In this study we extended the differential susceptibility hypothesis from a candidate gene to a genome-wide approach to test whether a polygenic score of environmental sensitivity predicted response to Cognitive Behavioural Therapy (CBT) in children with anxiety disorders. Methods: We identified variants associated with environmental sensitivity using a novel method in which within-pair variability in emotional problems in 1026 monozygotic (MZ) twin pairs was examined as a function of the pairs’ genotype. We created a polygenic score of environmental sensitivity based on the whole-genome findings and tested the score as a moderator of parenting on emotional problems in 1,406 children and response to individual, group and brief parent-led CBT in 973 children with anxiety disorders. Results: The polygenic score significantly moderated the effects of parenting on emotional problems and the effects of treatment. Individuals with a high score responded significantly better to individual CBT than group CBT or brief parent-led CBT (remission rates: 70.9%, 55.5% and 41.6% respectively). Conclusions: Pending successful replication, our results should be considered exploratory. Nevertheless, if replicated, they suggest that individuals with the greatest environmental sensitivity may be more likely to develop emotional problems in adverse environments, but also benefit more from the most intensive types of treatment.

The causal effect of family size on child labor and education

This paper investigates the causal relationship between family size and child labor and education among brazilian children. More especifically, it analyzes the impact of family size on child labor, school attendance, literacy and school progression. It explores the exogenous variation in family size driven by the presence of twins in the family. The results are consistent under the reasonable assumption that the instrument is a random event. Using the nationally representative brazilian household survey (Pnad), detrimental effects are found on child labor for boys. Moreover, significant effects are obtained for school progression for girls caused by the exogenous presence of the young siblings in the household.

New evidence of the causal effect of family size on child quality in a developing country

This paper presents new evidence of the causal effect of family size on child quality in a developing-country context. We estimate the impact of family size on child labor and educational outcomes among Brazilian children and young adults by exploring the exogenous variation of family size driven by the presence of twins in the family. Using the Brazilian Census data for 1991, we nd that the exogenous increase in family size is positively related to labor force participation for boys and girls and to household chores for young women. We also and negative e ects on educational outcomes for boys and girls and negative impacts on human capital formation for young female adults. Moreover, we obtain suggestive evidence that credit and time constraints faced by poor families may explain the findings.

Reproductive Patterns and Birth Seasonality in a South-American Breeding Colony of Common Marmosets, Callithrix jacchus

SOUSA,M.B.C. et al. Reproductive Patterns and Birth Seasonality in a South-American Breeding Colony of Common Marmosets, Callithrix jacchus. Primates, v.40, n.2, p. 327-336, Apr. 1999.

Engenharia de microestrutura em varistor à base de ZnO: evidências de homogeneidade e correlação com reações químicas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)