639 research outputs found
The impact of low, moderate, and high military family mobility school district transfer rates on graduating senior high school dependents\u27 achievement and school engagement
The results of this study suggest that there were no significant differences in the academic performance of military dependents\u27 with low (n = 20), moderate (n = 20), and high (n = 20) mobility school district transfer rates compared to non-military control students (n = 20) before completing high school. The findings were not consistent with some past research on student mobility. The research school district takes the goal of the Interstate Compact, which is to replace the widely varying treatment of transitioning military students with a comprehensive approach that provides a uniform policy in every school district in every state, very seriously. The research school district most likely sees consistently strong academic performance for its mobile military children because of the positive, and welcoming well-organized, goal-linked, and sustainable home, school, and community partnership supporting military dependents success at school. The school district involved in this research is but one of many public school districts in the United States that borders a military installation, thereby serving a diverse, military and civilian, student population. Additional research on the effect of mobility and the academic achievement of students in such districts is needed to better understand the effects of mobility, as well as the factors that moderate that relationship. In doing so, an important consideration is the possibility that school districts that serve a highly transient population become very adept at quickly and efficiently assessing and accommodating the learning needs of individual students. One would expect that in doing so, such school districts would effectively reduce or eliminate potentially negative effects of mobility
Taking into account nucleosomes for predicting gene expression
The eukaryotic genome is organized in a chain of nucleosomes that consist of 145-147. bp of DNA wrapped around a histone octamer protein core. Binding of transcription factors (TF) to nucleosomal DNA is frequently impeded, which makes it a challenging task to calculate TF occupancy at a given regulatory genomic site for predicting gene expression. Here, we review methods to calculate TF binding to DNA in the presence of nucleosomes. The main theoretical problems are (i) the computation speed that is becoming a bottleneck when partial unwrapping of DNA from the nucleosome is considered, (ii) the perturbation of the binding equilibrium by the activity of ATP-dependent chromatin remodelers, which translocate nucleosomes along the DNA, and (iii) the model parameterization from high-throughput sequencing data and fluorescence microscopy experiments in living cells. We discuss strategies that address these issues to efficiently compute transcription factor binding in chromatin. © 2013 Elsevier Inc
Increased urine IgM excretion predicts cardiovascular events in patients with type 1 diabetes nephropathy
<p>Abstract</p> <p>Background</p> <p>Diabetic nephropathy, a major complication of diabetes, is characterized by progressive renal injury and increased cardiovascular mortality. An increased urinary albumin excretion due dysfunction of the glomerular barrier is an early sign of diabetic nephropathy. An increased urinary excretion of higher molecular weight proteins such as IgM appears with progression of glomerular injury. We aim here to study the prognostic significance of urine IgM excretion in patients with type 1 diabetes mellitus (type 1 diabetic nephropathy).</p> <p>Methods</p> <p>This is an observational study of 139 patients with type1 diabetes mellitus (79 males and 60 females) under routine care at the diabetic outpatient clinic at the Lund University Hospital. The median follow-up time was 18 years (1 to 22) years. Urine albumin and urine IgM concentration were measured at time of recruitment.</p> <p>Results</p> <p>Overall 32 (14 male and 18 female) patients died in a cardiovascular event and 20 (11 male and 9 female) patients reached end-stage renal disease. Univariate analysis indicated that patient survival and renal survival were inversely associated with urine albumin excretion (RR = 2.9 and 5.8, respectively) and urine IgM excretion (RR = 4.6 and 5.7, respectively). Stratified analysis demonstrated that in patients with different degrees of albuminuria, the cardiovascular mortality rate and the incidence of end-stage renal disease was approximately three times higher in patients with increased urine IgM excretion.</p> <p>Conclusion</p> <p>An increase in urinary IgM excretion in patients with type 1 diabetes is associated with an increased risk for cardiovascular mortality and renal failure, regardless of the degree of albuminuria.</p
Trichostatin A induced histone acetylation causes decondensation of interphase chromatin.
The effect of trichostatin A (TSA)-induced histone
acetylation on the interphase chromatin structure was
visualized in vivo with a HeLa cell line stably expressing
histone H2A, which was fused to enhanced yellow
fluorescent protein. The globally increased histone
acetylation caused a reversible decondensation of dense
chromatin regions and led to a more homogeneous
distribution. These structural changes were quantified by
image correlation spectroscopy and by spatially resolved
scaling analysis. The image analysis revealed that a
chromatin reorganization on a length scale from 200 nm to
>1 mm was induced consistent with the opening of
condensed chromatin domains containing several Mb of DNA. The observed conformation changes could be
assigned to the folding of chromatin during G1 phase by
characterizing the effect of TSA on cell cycle progression
and developing a protocol that allowed the identification of
G1 phase cells on microscope coverslips. An analysis by
flow cytometry showed that the addition of TSA led to a
significant arrest of cells in S phase and induced apoptosis.
The concentration dependence of both processes was
studied
SMAD and p38 MAPK Signaling Pathways Independently Regulate α1(I) Collagen Gene Expression in Unstimulated and Transforming Growth Factor-β-stimulated Hepatic Stellate Cells
The hepatic stellate cell (HSC) is the predominant cell type responsible for excess collagen deposition during liver fibrosis. Both transforming growth factor-beta (TGF-beta), the most potent fibrogenic cytokine for HSCs, which classically activates Smad signaling, and p38 MAPK signaling have been shown to influence collagen gene expression; however, the relative contribution and mechanisms that these two signaling pathways have in regulating collagen gene expression have not been investigated. The aim of this study was to investigate the relative roles and mechanisms of both Smad and p38 MAPK signaling in alpha1(I) collagen gene expression in HSCs. Inhibiting either p38 MAPK or Smad signaling reduced alpha1(I) collagen mRNA expression in untreated or TGF-beta-treated HSCs, and when both signaling pathways were simultaneously inhibited, alpha1(I) collagen gene expression was essentially blocked. Both signaling pathways were found to independently and additively increase alpha1(I) collagen gene expression by transcriptional mechanisms. TGF-beta treatment increased alpha1(I) collagen mRNA half-life, mediated by increased stability of alpha1(I) collagen mRNA through p38 MAPK signaling but not through Smad signaling. In conclusion, both p38 MAPK and Smad signaling independently and additively regulate alpha1(I) collagen gene expression by transcriptional activation, whereas p38 MAPK and not Smad signaling increased alpha1(I) collagen mRNA stability
Protein Localization with Flexible DNA or RNA
Localization of activity is ubiquitous in life, and also within sub-cellular compartments. Localization provides potential advantages as different proteins involved in the same cellular process may supplement each other on a fast timescale. It might also prevent proteins from being active in other regions of the cell. However localization is at odds with the spreading of unbound molecules by diffusion. We model the cost and gain for specific enzyme activity using localization strategies based on binding to sites of intermediate specificity. While such bindings in themselves decrease the activity of the protein on its target site, they may increase protein activity if stochastic motion allows the acting protein to touch both the intermediate binding site and the specific site simultaneously. We discuss this strategy in view of recent suggestions on long non-coding RNA as a facilitator of localized activity of chromatin modifiers
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