636 research outputs found

    Alteración de las rocas gneisicas con riebeckita del área de Vigo

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    [Resumen] Se estudian los factores del medio físico, procesos de alteración y cambios químicos y mineralógicos producidos en la meteorización de un grupo de rocas gneisicas de composiciónquímica heterogénea en el área de Vigo. El proceso de alteración origina una saprolita masivade textura arenosa a areno-francosa, constituida por minerales heredados (cuarzo, feldespatos, plagioclasas, micas y anfíboles), micas degradadas y minerales neoformados (caolinita, gibbsita , goethita). El proceso de meteorización es una hidrólisis ácida con pérdida de bases y silicio y enriquecimiento relativo en aluminio. Los minerales de neoformación indican un predominio de la "monosialitización" cuando el sistema presenta drenaje ralentizado y de la "alitización")en fases incipientes de la alteración}cuando el sistema no tiene materia orgánica y el drenaje es excesivo[Abstract] It has been studied the physical environmental factors, alteration processes, and chemical and mineralogical changes produced during the gneisic rocks group from Vigo area ~eathering. ln these rocks great heterogenity in the chemical composition has been found. The weathering prevailing process in the area give rise to the formation of a saprolite with sandy to sandy-loamy textures,increasing permeability and it is composed of inherited minerals :quarz, feldspars and/or plagioclases,micas, amphiboles; neoformed materials, gibbsite,caolinite,goethite and degraded micas)the last two occasionally. The weathering process is an acid hydrolysis with desbasification and Al relative enrichment tendencies. With slow drainage systems the neoformed minerals indicate a monosiallitization predominance (formation of silicates 1:1); while 1ack i ng organ i c matter and in good dra i ned zones, the neoformed minerals indicate an incipient allititatio

    Elementos escasos y mineralizaciones metálicas en neises de la provincia de Pontevedra

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    [Resumen] Se estudió el contenido total, y en minerales no silicatédos, de Ni, Cu, Co, 2P y Ti en doce muestras representativas de los neises existentes en la provincia de Pontevedra. Se estableció la mineralogía y composición de Ios compuestos metálicos demostrándose la existencia de minerales de Ti en todas las muestras, en la mayoría rutilo con pequeñas cantidades de Fe en solucién sólida En otras apaecren cristales de ilmenita con Mn y Mg en solucién sólida al alguna de ellas. Se ha detectado la aparición de cristales de tumalina en la nuestra de neis glandular. Se han establecido las f ómuIas mineralógicas de todas las mineralizaciones metálicas localizada

    Valor de la expresión del ARN mensajero de la isocitrato deshidrogenasa (IDH1) como predictor de agresividad en gliomas

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    Los gliomas son el tipo más común de tumor cerebral primario. En humanos, cinco genes codifican para la isocitrato deshidrogenasa: IDH1/2/3A/3B/3G. Mutaciones somáticas puntuales en el gen IDH1 son frecuentes en gliomas, la mayoría transiciones de una sola base: 395G-A y están asociadas a una mayor supervivencia de esos pacientes con glioma cuando los comparamos con aquellos que no tienen la mutación. Entre las consecuencias funcionales de la mutación de la IDH1, estudios demuestran un fuerte descenso en la producción de NADPH reducido dependiente de isocitrato en las células. Investigamos la expresión del ARNm del IDH1 y la presencia o ausencia de la mutación G395A en una serie de gliomas. En particular, estudiamos 38 casos de gliomas y 7 metástasis analizando el centro y la periferia de muestras en fresco y resección en bloque. No encontramos diferencias entre las regiones central y periférica con respecto a la expresión del ARNm y la mutación de IDH1. Sin embargo, podemos observar una mayor expresión del ARNm de IDH1 y una menor incidencia de la mutación en tumores de alto grado cuando los comparamos con aquellos de bajo grado. Este estudio muestra que los gliomas con IDH1 normal tienen una mayor expresión de ARNm independientemente de la zona del tumor. Esto podría conducir a un aumento en la actividad enzimática y mayor presencia de NADPH, lo cual se necesita para el crecimiento celular. Así, el mayor poder de reducción de estas células podría explicar la mayor agresividad de estos gliomas.Gliomas, are the most common type of primary brain tumors. In humans, five genes encode for isocitrate dehydrogenase: IDH1, IDH2, IDH3A, IDH3B, and IDH3G. Somatic point mutations in IDH1 are frequent in gliomas. Most mutations for IDH1 are single base transition substitutions: 395G_A and are associated with longer survival in patients with glioma when compared with those gliomas without IDH1 mutations. Among the functional consequences of IDH1 mutation, some studies have shown a strong decrease in the isocitrate dependent production of reduced NADPH production in the cells. We investigated mRNA expression of IDH1 and the presence or absence of the G395A mutation in a subset of gliomas. Specifically, we studied 38 cases of glioma and 7 methastasis analyzing central and peripheral regions from fresh and en block resection specimens. We found no differences between central and peripheral regions, in regard to IDH1 mRNA expression and G395A IDH1 mutation. However, we identified a significantly higher expression of IDH1 mRNA and a lesser incidence of mutation in high grade gliomas when compared with low grade ones. This study shows that those gliomas with IDH1 WT are associated with higher expression of IDH1 mRNA, independently of the tumor area. This could in turn lead to an increase in enzyme activity and more presence of NADPH which is needed for cellular growth. The greater reducing power in these cells could account for the greater aggressiveness of these gliomas

    Adsorption of 2,2 '-dithiodipyridine as a tool for the assembly of silver nanoparticles

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    Silver nanostructured thin films stabilized by 2,2’-dithiodipyridine (2dtpy) were prepared. The Ag nanoparticles were obtained by treating the complex [Ag(2dtpy)]NO3 with NaBH4 in a methanol–toluene mixture. The films were transferred to borosilicate glass slips by a dip-coating method and were found to consist of Ag nanoparticles possibly linked via 2dtpy molecules. Surface-enhanced Raman scattering (SERS) studies have offered the possibility of investigating the adsorption modes of 2dtpy at the Ag nanoparticle surfaces in the fil

    Assessment of a targeted resequencing assay as a support tool in the diagnosis of lysosomal storage disorders

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    BACKGROUND: With over 50 different disorders and a combined incidence of up to 1/3000 births, lysosomal storage diseases (LSDs) constitute a major public health problem and place an enormous burden on affected individuals and their families. Many factors make LSD diagnosis difficult, including phenotype and penetrance variability, shared signs and symptoms, and problems inherent to biochemical diagnosis. Developing a powerful diagnostic tool could mitigate the protracted diagnostic process for these families, lead to better outcomes for current and proposed therapies, and provide the basis for more appropriate genetic counseling. METHODS: We have designed a targeted resequencing assay for the simultaneous testing of 57 lysosomal genes, using in-solution capture as the enrichment method and two different sequencing platforms. A total of 84 patients with high to moderate-or low suspicion index for LSD were enrolled in different centers in Spain and Portugal, including 18 positive controls. RESULTS: We correctly diagnosed 18 positive blinded controls, provided genetic diagnosis to 25 potential LSD patients, and ended with 18 diagnostic odysseys. CONCLUSION: We report the assessment of a next-generation-sequencing-based approach as an accessory tool in the diagnosis of LSDs, a group of disorders which have overlapping clinical profiles and genetic heterogeneity. We have also identified and quantified the strengths and limitations of next generation sequencing (NGS) technology applied to diagnosis

    Newborn screening for medium-chain acyl-CoA dehydrogenase deficiency: regional experience and high incidence of carnitine deficiency

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    Background Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is the most common inherited defect in the mitochondrial fatty acid oxidation pathway, resulting in significant morbidity and mortality in undiagnosed patients. Newborn screening (NBS) has considerably improved MCADD outcome, but the risk of complication remains in some patients. The aim of this study was to evaluate the relationship between genotype, biochemical parameters and clinical data at diagnosis and during follow-up, in order to optimize monitoring of these patients. Methods We carried out a multicenter study in southwest Europe, of MCADD patients detected by NBS. Evaluated NBS data included free carnitine (C0) and the acylcarnitines C8, C10, C10:1 together with C8/C2 and C8/C10 ratios, clinical presentation parameters and genotype, in 45 patients. Follow-up data included C0 levels, duration of carnitine supplementation and occurrence of metabolic crises. Results C8/C2 ratio and C8 were the most accurate biomarkers of MCADD in NBS. We found a high number of patients homozygous for the prevalent c.985A > G mutation (75%). Moreover, in these patients C8, C8/C10 and C8/C2 were higher than in patients with other genotypes, while median value of C0 was significantly lower (23 μmol/L vs 36 μmol/L). The average follow-up period was 43 months. To keep carnitine levels within the normal range, carnitine supplementation was required in 82% of patients, and for a longer period in patients homozygotes for the c.985A>G mutation than in patients with other genotypes (average 31 vs 18 months). Even with treatment, median C0 levels remained lower in homozygous patients than in those with other genotypes (14 μmol/L vs 22 μmol/L). Two patients died and another three suffered a metabolic crisis, all of whom were homozygous for the c.985 A>G mutation. Conclusions Our data show a direct association between homozygosity for c.985A>G and lower carnitine values at diagnosis, and a higher dose of carnitine supplementation for maintenance within the normal range. This study contributes to a better understanding of the relationship between genotype and phenotype in newborn patients with MCADD detected through screening which could be useful in improving follow-up strategies and clinical outcome

    Effects of different arachidonic acid supplementation on psychomotor development in very preterm infants; A randomized controlled trial

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    Background & aims: Nutritional supplementation with polyunsaturated fatty acids is important in preterm infants neurodevelopment, but it is not known if the omega-6/omega-3 ratio affects this process. This study was designed to determine the effects of a balanced contribution of arachidonic acid in very preterm newborns fed with formula milk. Methods: This was a randomized trial, in which newborns <1500 g and/or <32 weeks gestational age were assigned to one of two groups, based on the milk formula they would receive during the first year of life. Initially, 60 newborns entered the study, but ultimately, group A was composed of 24 newborns, who were given formula milk with an ω-6/ ω-3 ratio of 2/1, and Group B was composed of 21 newborns, given formula milk with an ω-6/ω-3 ratio of 1/1. The infants were followed up for two years: growth, visual-evoked potentials, brainstem auditory-evoked potentials, and plasma fatty acids were periodically measured, and psychomotor development was assessed using the Brunet Lézine scale at 24 months corrected age. A control group, for comparison of Brunet Lézine score, was made up of 25 newborns from the SEN1500 project, who were fed exclusively with breast milk. Results: At 12 months, arachidonic acid values were significantly higher in group A than in group B (6.95 ± 1.55 % vs. 4.55 ± 0.78 %), as were polyunsaturated fatty acids (41.02 ± 2.09 % vs. 38.08 ± 2.32 %) achieved a higher average. Group A achieved a higher average Brunet Lézine score at 24 months than group B (99.9 ± 9 vs. 90.8 ± 11, p =0.028). The Brunet Lézine results from group A were compared with the control group results, with very similar scores registered between the two groups (99.9 ± 9 vs. 100.5 ± 7). There were no significant differences in growth or evoked potentials between the two formula groups. Conclusions: Very preterm infants who received formula with an ω-6/ω-3 ratio of 2/1 had higher blood levels of essential fatty acids during the first year of life, and better psychomotor development, compared with very preterm newborns who consumed formula with an ω-6/ω-3 of 1/1. Therefore, formula milk with an arachidonic acid quantity double that of docosahexaenoic acid should be considered for feeding very preterm infants

    Newborn Screening for Homocystinuria Revealed a High Frequency of MAT I/III Deficiency in Iberian Peninsula

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    Acessível em: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4375120/Homocystinuria due to cystathionine β-synthase deficiency or "classical homocystinuria" is a rare autosomal recessive condition resulting in altered sulfur metabolism with elevated methionine and homocysteine in plasma and homocystine in urine. This condition is characterized by a high clinical heterogeneity, which contributes to late clinical diagnosis, usually only made after irreversible damage has occurred. Treatment is effective if started before clinical symptoms. The analysis of methionine levels by tandem mass spectrometry (MS/MS) allows the newborn screening for homocystinuria, but false-positive results can be frequently obtained and lead to the unwanted identification of methionine adenosyl transferase (MAT I/III) deficiency. This latter condition is biochemically characterized by isolated persistent hypermethioninemia, accompanied in some individuals with slightly elevated levels of homocysteine in plasma. A dominant form of MAT I/III deficiency, associated with mutation p.R264H, seems to be very frequent in the Iberian Peninsula and usually has a clinically benign course. Both these metabolic disorders are screened in Galicia and Portugal since the introduction of the MS/MS technology, in 2000 and 2004, respectively, resulting in the identification of three patients with classical homocystinuria and 44 patients with MAT I/III deficiency. All but one heterozygous parent of MAT I/III patients, identified with the p.R264H mutation, are healthy adults around the age of 30/40. The implementation of a second-tier test for homocysteine in dried blood spots would considerably reduce the number of MAT I/III-deficient patients identified and improve the specificity and positive predictive value for classical homocystinuria screening

    An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

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    For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
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