3,945 research outputs found
A framework for interpreting genome-wide association studies of psychiatric disorders
Genome-wide association studies (GWAS) have yielded a plethora of new findings in the past 3 years. By early 2009, GWAS on 47 samples of subjects with attention-deficit hyperactivity disorder, autism, bipolar disorder, major depressive disorder and schizophrenia will be completed. Taken together, these GWAS constitute the largest biological experiment ever conducted in psychiatry (59 000 independent cases and controls, 7700 family trios and >40 billion genotypes). We know that GWAS can work, and the question now is whether it will work for psychiatric disorders. In this review, we describe these studies, the Psychiatric GWAS Consortium for meta-analyses of these data, and provide a logical framework for interpretation of some of the conceivable outcomes
The role of nutrient loading and eutrophication in estuarine ecology.
Eutrophication is a process that can be defined as an increase in the rate of supply of organic matter (OM) to an ecosystem. We provide a general overview of the major features driving estuarine eutrophication and outline some of the consequences of that process. The main chemical constituent of OM is carbon (C), and therefore rates of eutrophication are expressed in units of C per area per unit time. OM occurs in both particulate and dissolved forms. Allochthonous OM originates outside the estuary, whereas autochthonous OM is generated within the system, mostly by primary producers or by benthic regeneration of OM. The supply rates of limiting nutrients regulate phytoplankton productivity that contributes to inputs of autochthonous OM. The trophic status of an estuary is often based on eutrophication rates and can be categorized as oligotrophic (<100 g C m(-2) y(-1), mesotrophic (100-300 g C m(-2) y(-1), eutrophic (300-500 g C m(-2) y(-1), or hypertrophic (>500 g C m(-2) y(-1). Ecosystem responses to eutrophication depend on both export rates (flushing, microbially mediated losses through respiration, and denitrification) and recycling/regeneration rates within the estuary. The mitigation of the effects of eutrophication involves the regulation of inorganic nutrient (primarily N and P) inputs into receiving waters. Appropriately scaled and parameterized nutrient and hydrologic controls are the only realistic options for controlling phytoplankton blooms, algal toxicity, and other symptoms of eutrophication in estuarine ecosystems
High star formation rates as the origin of turbulence in early and modern disk galaxies
High spatial and spectral resolution observations of star formation and
kinematics in early galaxies have shown that two-thirds are massive rotating
disk galaxies with the remainder being less massive non-rotating objects. The
line of sight averaged velocity dispersions are typically five times higher
than in today's disk galaxies. This has suggested that
gravitationally-unstable, gas-rich disks in the early Universe are fuelled by
cold, dense accreting gas flowing along cosmic filaments and penetrating hot
galactic gas halos. However these accreting flows have not been observed, and
cosmic accretion cannot power the observed level of turbulence. Here we report
on a new sample of rare high-velocity-dispersion disk galaxies we have
discovered in the nearby Universe where cold accretion is unlikely to drive
their high star-formation rates. We find that the velocity dispersion is most
fundamentally correlated with their star-formation rates, and not their mass
nor gas fraction, which leads to a new picture where star formation itself is
the energetic driver of galaxy disk turbulence at all cosmic epochs.Comment: 9 pages, 2 figures, Supplimentary Info available at:
http://pulsar.swin.edu.au/~agreen/nature/sigma_mean_arXiv.pdf. Accepted for
publication in Natur
Facilitating functional annotation of chicken microarray data
<p>Abstract</p> <p>Background</p> <p>Modeling results from chicken microarray studies is challenging for researchers due to little functional annotation associated with these arrays. The Affymetrix GenChip chicken genome array, one of the biggest arrays that serve as a key research tool for the study of chicken functional genomics, is among the few arrays that link gene products to Gene Ontology (GO). However the GO annotation data presented by Affymetrix is incomplete, for example, they do not show references linked to manually annotated functions. In addition, there is no tool that facilitates microarray researchers to directly retrieve functional annotations for their datasets from the annotated arrays. This costs researchers amount of time in searching multiple GO databases for functional information.</p> <p>Results</p> <p>We have improved the breadth of functional annotations of the gene products associated with probesets on the Affymetrix chicken genome array by 45% and the quality of annotation by 14%. We have also identified the most significant diseases and disorders, different types of genes, and known drug targets represented on Affymetrix chicken genome array. To facilitate functional annotation of other arrays and microarray experimental datasets we developed an Array GO Mapper (<it>AGOM</it>) tool to help researchers to quickly retrieve corresponding functional information for their dataset.</p> <p>Conclusion</p> <p>Results from this study will directly facilitate annotation of other chicken arrays and microarray experimental datasets. Researchers will be able to quickly model their microarray dataset into more reliable biological functional information by using <it>AGOM </it>tool. The disease, disorders, gene types and drug targets revealed in the study will allow researchers to learn more about how genes function in complex biological systems and may lead to new drug discovery and development of therapies. The GO annotation data generated will be available for public use via AgBase website and will be updated on regular basis.</p
Longer fixation duration while viewing face images
The spatio-temporal properties of saccadic eye movements can be influenced by the cognitive demand and the characteristics of the observed scene. Probably due to its crucial role in social communication, it is argued that face perception may involve different cognitive processes compared with non-face object or scene perception. In this study, we investigated whether and how face and natural scene images can influence the patterns of visuomotor activity. We recorded monkeys’ saccadic eye movements as they freely viewed monkey face and natural scene images. The face and natural scene images attracted similar number of fixations, but viewing of faces was accompanied by longer fixations compared with natural scenes. These longer fixations were dependent on the context of facial features. The duration of fixations directed at facial contours decreased when the face images were scrambled, and increased at the later stage of normal face viewing. The results suggest that face and natural scene images can generate different patterns of visuomotor activity. The extra fixation duration on faces may be correlated with the detailed analysis of facial features
Retargeted adenoviruses for radiation-guided gene delivery
The combination of radiation with radiosensitizing gene delivery or oncolytic viruses promises to provide an advantage that could improve the therapeutic results for glioblastoma. X-rays can induce significant molecular changes in cancer cells. We isolated the GIRLRG peptide that binds to radiation-inducible 78 kDa glucose-regulated protein (GRP78), which is overexpressed on the plasma membranes of irradiated cancer cells and tumor-associated microvascular endothelial cells. The goal of our study was to improve tumor-specific adenovirus-mediated gene delivery by selectively targeting the adenovirus binding to this radiation-inducible protein. We employed an adenoviral fiber replacement approach to conduct a study of the targeting utility of GRP78-binding peptide. We have developed fiber-modified adenoviruses encoding the GRP78-binding peptide inserted into the fiber-fibritin. We have evaluated the reporter gene expression of fiber-modified adenoviruses in vitro using a panel of glioma cells and a human D54MG tumor xenograft model. The obtained results demonstrated that employment of the GRP78-binding peptide resulted in increased gene expression in irradiated tumors following infection with fiber-modified adenoviruses, compared with untreated tumor cells. These studies demonstrate the feasibility of adenoviral retargeting using the GRP78-binding peptide that selectively recognizes tumor cells responding to radiation treatment
Pulmonary intravascular macrophages: Prime suspects as cellular mediators of porcine CARPA
Pigs provide a highly sensitive and quantitative in vivo model for complement (C) activation-related pseudoallergy (CARPA), a hypersensitivity reaction caused by some state-of-art nanomedicines. In an effort to understand the mechanism of the pigs' unique sensitivity for CARPA, this review focuses on pulmonary intravascular macrophages (PIMs), which are abundantly present in the lung of pigs. These cells represent a macrophage subpopulation whose unique qualities explain the characteristic symptoms of CARPA in this species, most importantly the rapidly (within minutes) developing pulmonary vasoconstriction, leading to elevation of pulmonary arterial pressure. The unique qualities of PIM cells include the following; 1) they are strongly adhered to the capillary walls via desmosome-like intercellular adhesion plaques, which secure stable and lasting direct exposition of the bulk of these cells to the blood stream; 2) their ruffled surface engaged in intense phagocytic activity ensures efficient binding and phagocytosis of nanoparticles; 3) PIM cells express anaphylatoxin receptors, this way C activation can trigger these cells, 4) they also express pattern recognition molecules on their surface, whose engagement with certain coated nanoparticles may also activate these cells or act in synergy with anaphylatoxins and, finally 5) their high metabolic activity and capability for immediate secretion of vasoactive mediators upon stimulation explain the circulatory blockage and other robust physiological effects that their stimulation may cause. These qualities taken together with reports on liposome uptake by PIM cells during CARPA and the possible presence of these cells in human lung suggests that PIM cells may be a potential therapeutic target against CARPA. © 2015 by De Gruyter
FIRE (facilitating implementation of research evidence) : a study protocol
Research evidence underpins best practice, but is not always used in healthcare. The Promoting Action on Research Implementation in Health Services (PARIHS) framework suggests that the nature of evidence, the context in which it is used, and whether those trying to use evidence are helped (or facilitated) affect the use of evidence. Urinary incontinence has a major effect on quality of life of older people, has a high prevalence, and is a key priority within European health and social care policy. Improving continence care has the potential to improve the quality of life for older people and reduce the costs associated with providing incontinence aids
Peer navigation improves diagnostic follow-up after breast cancer screening among Korean American women: results of a randomized trial
To test an intervention to increase adherence to diagnostic follow-up tests among Asian American women.
Korean American women who were referred for a diagnostic follow-up test (mainly diagnostic mammograms) and who had missed their follow-up appointment were eligible to participate in the study. Women from two clinics (n = 176) were randomly allocated to a usual care control arm or a peer navigator intervention arm. A 20-min telephone survey was administered to women in both study arms six months after they were identified to assess demographic and socio-economic characteristics and the primary outcome, self-reported completion of the recommended follow-up exam.
Among women who completed the survey at six-month follow-up, self-reported completion of follow-up procedures was 97% in the intervention arm and 67% in the control arm (p < 0.001). Based on an intent-to-treat analysis of all women who were randomized and an assumption of no completion of follow-up exam for women with missing outcome data, self-reported completion of follow-up was 61% in the intervention arm and 46% in the usual care control arm (p < 0.069).
Our results suggest that a peer navigator intervention to assist Korean American women to obtain follow-up diagnostic tests after an abnormal breast cancer screening test is efficacious
Multiethnic Genetic Association Studies Improve Power for Locus Discovery
To date, genome-wide association studies have focused almost exclusively on populations of European ancestry. These studies continue with the advent of next-generation sequencing, designed to systematically catalog and test low-frequency variation for a role in disease. A complementary approach would be to focus further efforts on cohorts of multiple ethnicities. This leverages the idea that population genetic drift may have elevated some variants to higher allele frequency in different populations, boosting statistical power to detect an association. Based on empirical allele frequency distributions from eleven populations represented in HapMap Phase 3 and the 1000 Genomes Project, we simulate a range of genetic models to quantify the power of association studies in multiple ethnicities relative to studies that exclusively focus on samples of European ancestry. In each of these simulations, a first phase of GWAS in exclusively European samples is followed by a second GWAS phase in any of the other populations (including a multiethnic design). We find that nontrivial power gains can be achieved by conducting future whole-genome studies in worldwide populations, where, in particular, African populations contribute the largest relative power gains for low-frequency alleles (<5%) of moderate effect that suffer from low power in samples of European descent. Our results emphasize the importance of broadening genetic studies to worldwide populations to ensure efficient discovery of genetic loci contributing to phenotypic trait variability, especially for those traits for which large numbers of samples of European ancestry have already been collected and tested
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