761 resultados para imprinting approaches
Resumo:
BACKGROUND: Porcine IGF2 and the H19 genes are imprinted. The IGF2 is paternally expressed, while the H19 gene is maternally expressed. Extensive studies in mice established a boundary model indicating that the H19 differentially methylated domain (DMD) controls, upon binding with the CTCF protein, reciprocal imprinting of the IGF2 and the H19 genes. IGF2 transcription is tissue and development specific involving the use of 4 promoters. In the liver of adult Large White boars IGF2 is expressed from both parental alleles, whereas in skeletal muscle and kidney tissues we observed variable relaxation of IGF2 imprinting. We hypothesized that IGF2 expression from both paternal alleles and relaxation of IGF2 imprinting is reflected in differences in DNA methylation patterns at the H19 DMD and IGF2 differentially methylated regions 1 and 2 (DMR1 and DMR2). RESULTS: Bisulfite sequencing analysis did not show any differences in DNA methylation at the three porcine CTCF binding sites in the H19 DMD between liver, muscle and kidney tissues of adult pigs. A DNA methylation analysis using methyl-sensitive restriction endonuclease SacII and 'hot-stop' PCR gave consistent results with those from the bisulfite sequencing analysis. We found that porcine H19 DMD is distinctly differentially methylated, at least for the region formally confirmed by two SNPs, in liver, skeletal muscle and kidney of foetal, newborn and adult pigs, independent of the combined imprinting status of all IGF2 expressed transcripts. DNA methylation at CpG sites in DMR1 of foetal liver was significantly lower than in the adult liver due to the presence of hypomethylated molecules. An allele specific analysis was performed for IGF2 DMR2 using a SNP in the IGF2 3'-UTR. The maternal IGF2 DMR2 of foetal and newborn liver revealed a higher DNA methylation content compared to the respective paternal allele. CONCLUSIONS: Our results indicate that the IGF2 imprinting status is transcript-specific. Biallelic IGF2 expression in adult porcine liver and relaxation of IGF2 imprinting in porcine muscle were a common feature. These results were consistent with the IGF2 promoter P1 usage in adult liver and IGF2 promoter P2, P3 and P4 usages in muscle. The results showed further that bialellic IGF2 expression in liver and relaxation of imprinting in muscle and kidney were not associated with DNA methylation variation at and around at least one CTCF binding site in H19 DMD. The imprinting status in adult liver, muscle and kidney tissues were also not reflected in the methylation patterns of IGF2 DMRs 1 and 2.
Resumo:
Hypereosinophilic syndromes (HES) are a heterogeneous group of disorders that range from asymptomatic eosinophilia > 1,500/mL to aggressive disease complicated by life-threatening end organ involvement, including endomyocardial fibrosis and thromboembolism. To complicate matters further, similar clinical manifestations can occur in the setting of marked eosinophilia due to helminth infection, drug hypersensitivity, and other causes. In the past, therapy was guided only by the exclusion of these secondary causes of eosinophilia and the severity of the clinical manifestations. More recently, the availability of novel targeted therapies and a better understanding of the etiologies of some subtypes of HES have necessitated a more structured approach.
Resumo:
Independent component analysis (ICA) or seed based approaches (SBA) in functional magnetic resonance imaging blood oxygenation level dependent (BOLD) data became widely applied tools to identify functionally connected, large scale brain networks. Differences between task conditions as well as specific alterations of the networks in patients as compared to healthy controls were reported. However, BOLD lacks the possibility of quantifying absolute network metabolic activity, which is of particular interest in the case of pathological alterations. In contrast, arterial spin labeling (ASL) techniques allow quantifying absolute cerebral blood flow (CBF) in rest and in task-related conditions. In this study, we explored the ability of identifying networks in ASL data using ICA and to quantify network activity in terms of absolute CBF values. Moreover, we compared the results to SBA and performed a test-retest analysis. Twelve healthy young subjects performed a fingertapping block-design experiment. During the task pseudo-continuous ASL was measured. After CBF quantification the individual datasets were concatenated and subjected to the ICA algorithm. ICA proved capable to identify the somato-motor and the default mode network. Moreover, absolute network CBF within the separate networks during either condition could be quantified. We could demonstrate that using ICA and SBA functional connectivity analysis is feasible and robust in ASL-CBF data. CBF functional connectivity is a novel approach that opens a new strategy to evaluate differences of network activity in terms of absolute network CBF and thus allows quantifying inter-individual differences in the resting state and task-related activations and deactivations.
Resumo:
The immune system exhibits an enormous complexity. High throughput methods such as the "-omic'' technologies generate vast amounts of data that facilitate dissection of immunological processes at ever finer resolution. Using high-resolution data-driven systems analysis, causal relationships between complex molecular processes and particular immunological phenotypes can be constructed. However, processes in tissues, organs, and the organism itself (so-called higher level processes) also control and regulate the molecular (lower level) processes. Reverse systems engineering approaches, which focus on the examination of the structure, dynamics and control of the immune system, can help to understand the construction principles of the immune system. Such integrative mechanistic models can properly describe, explain, and predict the behavior of the immune system in health and disease by combining both higher and lower level processes. Moving from molecular and cellular levels to a multiscale systems understanding requires the development of methodologies that integrate data from different biological levels into multiscale mechanistic models. In particular, 3D imaging techniques and 4D modeling of the spatiotemporal dynamics of immune processes within lymphoid tissues are central for such integrative approaches. Both dynamic and global organ imaging technologies will be instrumental in facilitating comprehensive multiscale systems immunology analyses as discussed in this review.
Resumo:
This article reviews the process of intervention research, with particular emphasis on interventions with and for older adults. First, we consider the context of intervention research: What are the resources and constraints that shape the process of intervention and research? Second, we outline a taxonomy of interventions, reflecting different combinations of level and timing of interventions. Third, we consider the types of research designs that are most appropriate in the different contexts of applied research.
Resumo:
Nurse's aides are the primary caregivers in nursing homes, a major receiving site for elders with behavioral and psychiatric problems. We describe the development, psychometric properties, and utility of a brief instrument designed to assess aides' knowledge of three specific mental health problems (depression, agitation, and disorientation) and behavioral approaches to them. The instrument was administered to 191 nurse's aides and 21 clinicians with training in behavioral management and experience with older residents. The nurse's aides averaged 11 of 17 correct answers, and the clinicians averaged 15 of 17 correct answers. Implications for staff training and consultation activities in nursing homes are discussed.
Resumo:
The application of scientific-based conservation measures requires that sampling methodologies in studies modelling similar ecological aspects produce comparable results making easier their interpretation. We aimed to show how the choice of different methodological and ecological approaches can affect conclusions in nest-site selection studies along different Palearctic meta-populations of an indicator species. First, a multivariate analysis of the variables affecting nest-site selection in a breeding colony of cinereous vulture (Aegypius monachus) in central Spain was performed. Then, a meta-analysis was applied to establish how methodological and habitat-type factors determine differences and similarities in the results obtained by previous studies that have modelled the forest breeding habitat of the species. Our results revealed patterns in nesting-habitat modelling by the cinereous vulture throughout its whole range: steep and south-facing slopes, great cover of large trees and distance to human activities were generally selected. The ratio and situation of the studied plots (nests/random), the use of plots vs. polygons as sampling units and the number of years of data set determined the variability explained by the model. Moreover, a greater size of the breeding colony implied that ecological and geomorphological variables at landscape level were more influential. Additionally, human activities affected in greater proportion to colonies situated in Mediterranean forests. For the first time, a meta-analysis regarding the factors determining nest-site selection heterogeneity for a single species at broad scale was achieved. It is essential to homogenize and coordinate experimental design in modelling the selection of species' ecological requirements in order to avoid that differences in results among studies would be due to methodological heterogeneity. This would optimize best conservation and management practices for habitats and species in a global context.
Resumo:
The application of luminescence dating to young volcanic sediments has been first investigated over three decades ago, but it was only with the technical innovations of the last decade that such analyses became viable. While current analytical procedures show promise for dating late Quaternary volcanic events, most efforts have been aimed at unconsolidated volcanic tephra. Investigations into direct dating of lava flows or of non-heated volcanoclastics like phreatic explosion layers, however, remain scarce. These volcanic deposits are of common occurrence and represent important chrono- and volcanostratigraphic markers. Their age determination is therefore of great importance in volcanologic, tectonic, geomorphological and climate studies. In this article, we propose the use of phreatic explosion deposits and xenolithic inclusions in lava flows as target materials for luminescence dating applications. The main focus is on the crucial criterion whether it is probable that such materials experience complete luminescence signal resetting during the volcanic event to be dated. This is argued based on the findings from existing literature, model calculations and laboratory tests.