333 research outputs found

    Older Aboriginal Australians' Health Concerns and Preferences for Healthy Ageing Programs.

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    While there is strong evidence of the need for healthy ageing programs for older Aboriginal Australians, few are available. It is important to understand older Aboriginal Australians' perspectives on healthy ageing in order to co-design culturally-appropriate programs, including views on technology use in this context. Semi-structured interviews were conducted with 34 Aboriginal Australians aged 50 years and older from regional and urban communities to explore participants' health concerns, preferences for healthy ageing programs, and receptiveness to technology. Qualitative data were analyzed using a grounded theory approach. This study found that older Aboriginal Australians are concerned about chronic health conditions, social and emotional well-being, and difficulties accessing health services. A range of barriers and enablers to participation in current health programs were identified. From the perspective of older Aboriginal people, a successful healthy ageing program model includes physical and cognitive activities, social interaction, and health education. The program model also provides culturally safe care and transport for access as well as family, community, cultural identity, and empowerment regarding ageing well as central tenets. Technology could also be a viable approach for program delivery. These findings can be applied in the implementation and evaluation of culturally-appropriate, healthy ageing programs with older Aboriginal people

    A Cellular Automata Model for Citrus Variagated Chlorosis

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    A cellular automata model is proposed to analyze the progress of Citrus Variegated Chlorosis epidemics in S\~ao Paulo oranges plantation. In this model epidemiological and environmental features, such as motility of sharpshooter vectors which perform L\'evy flights, hydric and nutritional level of plant stress and seasonal climatic effects, are included. The observed epidemics data were quantitatively reproduced by the proposed model varying the parameters controlling vectors motility, plant stress and initial population of diseased plants.Comment: 10 pages, 10 figures, Scheduled tentatively for the issue of: 01Nov0

    Oxysterol Binding Protein-dependent Activation of Sphingomyelin Synthesis in the Golgi Apparatus Requires Phosphatidylinositol 4-Kinase IIĪ±

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    The study identifies a sterol- and oxysterol binding protein (OSBP)-regulated phosphatidylinositol 4-kinase that regulates ceramide transport protein (CERT) activity and sphingomyelin (SM) synthesis. RNA interference silencing experiments identify PI4KIIĪ±; as the mediator of Golgi recruitment of CERT, providing a potential mechanism for coordinating assembly of SM and cholesterol in the Golgi or more distal compartments

    Systems based analysis of human embryos and gene networks involved in cell lineage allocation.

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    BACKGROUND: Little is understood of the molecular mechanisms involved in the earliest cell fate decision in human development, leading to the establishment of the trophectoderm (TE) and inner cell mass (ICM) stem cell population. Notably, there is a lack of understanding of how transcriptional networks arise during reorganisation of the embryonic genome post-fertilisation. RESULTS: We identified a hierarchical structure of preimplantation gene network modules around the time of embryonic genome activation (EGA). Using network models along with eukaryotic initiation factor (EIF) and epigenetic-associated gene expression we defined two sets of blastomeres that exhibited diverging tendencies towards ICM or TE. Analysis of the developmental networks demonstrated stage specific EIF expression and revealed that histone modifications may be an important epigenetic regulatory mechanism in preimplantation human embryos. Comparison to published RNAseq data confirmed that during EGA the individual 8-cell blastomeres are transcriptionally primed for the first lineage decision in development towards ICM or TE. CONCLUSIONS: Using multiple systems biology approaches to compare developmental stages in the early human embryo with single cell transcript data from blastomeres, we have shown that blastomeres considered to be totipotent are not transcriptionally equivalent. Furthermore we have linked the developmental interactome to individual blastomeres and to later cell lineage. This has clinical implications for understanding the impact of fertility treatments and developmental programming of long term health

    Ecological Invasion, Roughened Fronts, and a Competitor's Extreme Advance: Integrating Stochastic Spatial-Growth Models

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    Both community ecology and conservation biology seek further understanding of factors governing the advance of an invasive species. We model biological invasion as an individual-based, stochastic process on a two-dimensional landscape. An ecologically superior invader and a resident species compete for space preemptively. Our general model includes the basic contact process and a variant of the Eden model as special cases. We employ the concept of a "roughened" front to quantify effects of discreteness and stochasticity on invasion; we emphasize the probability distribution of the front-runner's relative position. That is, we analyze the location of the most advanced invader as the extreme deviation about the front's mean position. We find that a class of models with different assumptions about neighborhood interactions exhibit universal characteristics. That is, key features of the invasion dynamics span a class of models, independently of locally detailed demographic rules. Our results integrate theories of invasive spatial growth and generate novel hypotheses linking habitat or landscape size (length of the invading front) to invasion velocity, and to the relative position of the most advanced invader.Comment: The original publication is available at www.springerlink.com/content/8528v8563r7u2742

    Mechanisms Underlying Interferon-Ī³-Induced Priming of Microglial Reactive Oxygen Species Production.

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    Microglial priming and enhanced reactivity to secondary insults cause substantial neuronal damage and are hallmarks of brain aging, traumatic brain injury and neurodegenerative diseases. It is, thus, of particular interest to identify mechanisms involved in microglial priming. Here, we demonstrate that priming of microglia with interferon-Ī³ (IFN Ī³) substantially enhanced production of reactive oxygen species (ROS) following stimulation of microglia with ATP. Priming of microglial ROS production was substantially reduced by inhibition of p38 MAPK activity with SB203580, by increases in intracellular glutathione levels with N-Acetyl-L-cysteine, by blockade of NADPH oxidase subunit NOX2 activity with gp91ds-tat or by inhibition of nitric oxide production with L-NAME. Together, our data indicate that priming of microglial ROS production involves reduction of intracellular glutathione levels, upregulation of NADPH oxidase subunit NOX2 and increases in nitric oxide production, and suggest that these simultaneously occurring processes result in enhanced production of neurotoxic peroxynitrite. Furthermore, IFNĪ³-induced priming of microglial ROS production was reduced upon blockade of Kir2.1 inward rectifier K+ channels with ML133. Inhibitory effects of ML133 on microglial priming were mediated via regulation of intracellular glutathione levels and nitric oxide production. These data suggest that microglial Kir2.1 channels may represent novel therapeutic targets to inhibit excessive ROS production by primed microglia in brain pathology

    Incomplete homogenization of 18 S ribosomal DNA coding regions in Arabidopsis thaliana

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    <p>Abstract</p> <p>Background</p> <p>As a result of concerted evolution, coding regions of ribosomal DNA sequences are highly conserved within species and variation is generally thought to be limited to a few nucleotides. However, rDNA sequence variation has not been systematically examined in plant genomes, including that of the model plant <it>Arabidopsis thaliana </it>whose genome was the first to be sequenced.</p> <p>Findings</p> <p>Both genomic and transcribed 18 S sequences were sampled and revealed that most deviation from the consensus sequence was limited to single nucleotide substitutions except for a variant with a 270 bp deletion from position 456 to 725 in <it>Arabidopsis </it>numbering. The deletion maps to the functionally important and highly conserved 530 loop or helix18 in the structure of <it>E. coli </it>16 S. The expression of the deletion variant is tightly controlled during developmental growth stages. Transcripts were not detectable in young seedlings but could be amplified from RNA extracts of mature leaves, stems, flowers and roots of <it>Arabidopsis thaliana </it>ecotype Columbia. We also show polymorphism for the deletion variant among four <it>Arabidopsis </it>ecotypes examined.</p> <p>Conclusion</p> <p>Despite a strong purifying selection that might be expected against functionally impaired rDNAs, the newly identified variant is maintained in the <it>Arabidopsis </it>genome. The expression of the variant and the polymorphism displayed by <it>Arabidopsis </it>ecotypes suggest a transition state in concerted evolution.</p

    GTP-dependent structural rearrangement of the eRF1:eRF3 complex and eRF3 sequence motifs essential for PABP binding

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    Translation termination in eukaryotes is governed by the concerted action of eRF1 and eRF3 factors. eRF1 recognizes the stop codon in the A site of the ribosome and promotes nascent peptide chain release, and the GTPase eRF3 facilitates this peptide release via its interaction with eRF1. In addition to its role in termination, eRF3 is involved in normal and nonsense-mediated mRNA decay through its association with cytoplasmic poly(A)-binding protein (PABP) via PAM2-1 and PAM2-2 motifs in the N-terminal domain of eRF3. We have studied complex formation between full-length eRF3 and its ligands (GDP, GTP, eRF1 and PABP) using isothermal titration calorimetry, demonstrating formation of the eRF1:eRF3:PABP:GTP complex. Analysis of the temperature dependence of eRF3 interactions with G nucleotides reveals major structural rearrangements accompanying formation of the eRF1:eRF3:GTP complex. This is in contrast to eRF1:eRF3:GDP complex formation, where no such rearrangements were detected. Thus, our results agree with the established active role of GTP in promoting translation termination. Through point mutagenesis of PAM2-1 and PAM2-2 motifs in eRF3, we demonstrate that PAM2-2, but not PAM2-1 is indispensible for eRF3:PABP complex formation

    Identifying important questions for Cochrane systematic reviews in Eyes and Vision: Report of a priority setting exercise

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    Introduction Systematic reviews are important to inform decision-making for evidence-based health care and patient choice. Deciding which reviews should be prioritized is a key issue for decision-makers and researchers. Cochrane Eyes and Vision conducted a priority setting exercise for systematic reviews in eye health care. Methods We established a steering group including practitioners, patient organizations, and researchers. To identify potential systematic review questions, we searched global policy reports, research prioritization exercises, guidelines, systematic review databases, and the Cochrane Library (CENTRAL). We grouped questions into separate condition lists and conducted a two-round online modified Delphi survey, including a ranking request. Participants in the survey were recruited through social media and the networks of the steering group. Results In Round 1, 343 people ranked one or more of the condition lists. Participants were eye care practitioners (69%), researchers (37%), patients or carers (24%), research providers/funders (5%), or noneye health care practitioners (4%) and from all World Health Organization regions. Two hundred twenty-six people expressed interest in completing Round 2 and 160 of these (71%) completed the Round 2 survey. Reviews on cataract and refractive error, reviews relevant to children, and reviews on rehabilitation were considered to have an important impact on the magnitude of disease and equity. Narrative comments emphasized the need for reviews on access to eye health care, particularly for underserved groups, including people with intellectual disabilities. Conclusion A global group of stakeholders prioritized questions on the effective and equitable delivery of services for eye health care. When considering the impact of systematic reviews in terms of reducing the burden of eye conditions, equity is clearly an important criterion to consider in priority-setting exercises
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