142 research outputs found

    Growth rate, extinction and survival amongst late Cenozoic bivalves of the North Atlantic

    Get PDF
    Late Cenozoic bivalve extinction in the North Atlantic and adjacent areas has been attributed to environmental change (declines in temperature and primary production). Within scallops and oysters—bivalve groups with a high growth rate—certain taxa which grew exceptionally fast became extinct, while others which grew slower survived. The taxa which grew exceptionally fast would have obtained protection from predators thereby, so their extinction may have been due to the detrimental effect of environmental change on growth rate and ability to avoid predation, rather than environmental change per se. We investigated some glycymeridid and carditid bivalves—groups with a much lower growth rate than scallops and oysters—to see whether extinct forms from the late Cenozoic of the North Atlantic grew faster than extant forms, and hence whether their extinction may also have been mediated by increased mortality due to predation. Growth rate was determined from the cumulative width of annual increments in the hinge area; measurements were scaled up to overall shell size for the purposes of comparison with data from living species. Growth of the extinct glycymeridid Glycymeris subovata was at about the same rate as the slowest-growing living glycymeridid and much slower than in late Cenozoic samples of extant G. americana, in which growth was at about the same rate as the fastest-growing living glycymeridid. Growth of extinct G. obovata was also slower than G. americana, and that of the extinct carditid Cardites squamulosa ampla similarly slow (evidently slower than in the one living carditid species for which data are available). These findings indicate that within bivalve groups whose growth is much slower than scallops and oysters, extinction or survival of taxa through the late Cenozoic was not influenced by whether they were relatively fast or slow growers. By implication, environmental change acted directly to cause extinctions in slow-growing groups, rather than by increasing susceptibility to predation.University of Derby: URSS 2017-028, URSS 2017-02

    Temporary Closure of the Open Abdomen: A Systematic Review on Delayed Primary Fascial Closure in Patients with an Open Abdomen

    Get PDF
    Background This study was designed to systematically review the literature to assess which temporary abdominal closure (TAC) technique is associated with the highest delayed primary fascial closure (FC) rate. In some cases of abdominal trauma or infection, edema or packing precludes fascial closure after laparotomy. This "open abdomen'' must then be temporarily closed. However, the FC rate varies between techniques. Methods The Cochrane Register of Controlled Trials, MEDLINE, and EMBASE databases were searched until December 2007. References were checked for additional studies. Search criteria included (synonyms of) "open abdomen,'' "fascial closure,'' "vacuum,'' "reapproximation,'' and "ventral hernia.'' Open abdomen was defined as "the inability to close the abdominal fascia after laparotomy.'' Two reviewers independently extracted data from original articles by using a predefined checklist. Results The search identified 154 abstracts of which 96 were considered relevant. No comparative studies were identified. After reading them, 51 articles, including 57 case series were included. The techniques described were vacuum-assisted closure (VAC; 8 series), vacuum pack (15 series), artificial burr (4 series), Mesh/sheet (16 series), zipper (7 series), silo (3 series), skin closure (2 series), dynamic retention sutures (DRS), and loose packing (1 series each). The highest FC rates were seen in the artificial burr (90%), DRS (85%), and VAC (60%). The lowest mortality rates were seen in the artificial burr (17%), VAC (18%), and DRS (23%). Conclusions These results suggest that the artificial burr and the VAC are associated with the highest FC rates and the lowest mortality rate

    Adult hippocampal neuroplasticity triggers susceptibility to recurrent depression

    Get PDF
    Depression is a highly prevalent and recurrent neuropsychiatric disorder associated with alterations in emotional and cognitive domains. Neuroplastic phenomena are increasingly considered central to the etiopathogenesis of and recovery from depression. Nevertheless, a high number of remitted patients experience recurrent episodes of depression, remaining unclear how previous episodes impact on behavior and neuroplasticity and/or whether modulation of neuroplasticity is important to prevent recurrent depression. Through re-exposure to an unpredictable chronic mild stress protocol in rats, we observed the re-appearance of emotional and cognitive deficits. Furthermore, treatment with the antidepressants fluoxetine and imipramine was effective to promote sustained reversion of a depressive-like phenotype; however, their differential impact on adult hippocampal neuroplasticity triggered a distinct response to stress re-exposure: while imipramine re-established hippocampal neurogenesis and neuronal dendritic arborization contributing to resilience to recurrent depressive-like behavior, stress re-exposure in fluoxetine-treated animals resulted in an overproduction of adult-born neurons along with neuronal atrophy of granule neurons, accounting for an increased susceptibility to recurrent behavioral changes typical of depression. Strikingly, cell proliferation arrest compromised the behavior resilience induced by imipramine and buffered the susceptibility to recurrent behavioral changes promoted by fluoxetine. This study shows that previous exposure to a depressive-like episode impacts on the behavioral and neuroanatomical changes triggered by subsequent re-exposure to similar experimental conditions and reveals that the proper control of adult hippocampal neuroplasticity triggered by antidepressants is essential to counteract recurrent depressive-like episodes.FCT (IF/01079/2014). This article has been developed under the scope of the project NORTE-01-0145-FEDER-000013, supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER). This work has been funded by FEDER funds, through the Competitiveness Factors Operational Programme (COMPETE), and by National funds, through the FCT, under the scope of the project POCI-01-0145-FEDER-007038info:eu-repo/semantics/publishedVersio

    Association of temporal factors and suicides in the United States, 2000–2004

    Get PDF
    The purpose of the study was to examine the association of temporal factors, in particular days of the week and seasons of the year and death from suicide in the United States. Data were pooled from the Multiple Cause of Death Files. Hierarchical logistic regression models were fitted to all deaths occurring in 2000 through 2004 by suicide. The incidence of suicide was significantly higher on Wednesdays, compared to Sunday. Specifically, individuals were 99% more likely to kill themselves on Wednesday than on Sunday. Suicides were more prevalent in the summer months, and they were less likely to occur in winter. The state suicide rate significantly elevated individual suicide risk. The results held even after controlling for the potentially confounding effects of socio-economic and demographic variables at both the individual and state levels. It was concluded that the observed association between seasonality and suicide cannot be discounted as a mere coincidence. Future research ought to focus on integrating individual level data and contextual variables when testing for seasonality effects

    Transcriptome Analysis of Epithelial and Stromal Contributions to Mammogenesis in Three Week Prepartum Cows

    Get PDF
    Transcriptome analysis of bovine mammary development has provided insight into regulation of mammogenesis. However, previous studies primarily examined expression of epithelial and stromal tissues combined, and consequently did not account for tissue specific contribution to mammary development. Our objective was to identify differences in gene expression in epithelial and intralobular stromal compartments. Tissue was biopsied from non-lactating dairy cows 3 weeks prepartum, cut into explants and incubated for 2 hr with insulin and hydrocortisone. Epithelial and intralobular stromal tissues were isolated with laser capture microdissection. Global gene expression was measured with Bovine Affymetrix GeneChips, and data were preprocessed using RMA method. Moderated t-tests from gene-specific linear model analysis with cell type as a fixed effect showed more than 3,000 genes were differentially expressed between tissues (P<0.05; FDR<0.17). Analysis of epithelial and stromal transcriptomes using Database for Annotation, Visualization and Integrated Discovery (DAVID) and Ingenuity Pathways Analysis (IPA) showed that epithelial and stromal cells contributed distinct molecular signatures. Epithelial signatures were enriched with gene sets for protein synthesis, metabolism and secretion. Stromal signatures were enriched with genes that encoded molecules important to signaling, extracellular matrix composition and remodeling. Transcriptome differences also showed evidence for paracrine interactions between tissues in stimulation of IGF1 signaling pathway, stromal reaction, angiogenesis, neurogenesis, and immune response. Molecular signatures point to the dynamic role the stroma plays in prepartum mammogenesis and highlight the importance of examining the roles of cell types within the mammary gland when targeting therapies and studying mechanisms that affect milk production

    The Leukemia-Specific Fusion Gene ETV6/RUNX1 Perturbs Distinct Key Biological Functions Primarily by Gene Repression

    Get PDF
    -positive leukemic cell lines.-positive ALL samples underline the relevance of these pathways and molecular functions. We also validated six differentially expressed genes representing the categories “stem cell properties”, “B-cell differentiation”, “immune response”, “cell adhesion” and “DNA damage” with RT-qPCR. fusion gene interferes with key regulatory functions that shape the biology of this leukemia subtype. E/R may thus indeed constitute the essential driving force for the propagation and maintenance of the leukemic process irrespective of potential consequences of associated secondary changes. Finally, these findings may also provide a valuable source of potentially attractive therapeutic targets

    RNA delivery by extracellular vesicles in mammalian cells and its applications.

    Get PDF
    The term 'extracellular vesicles' refers to a heterogeneous population of vesicular bodies of cellular origin that derive either from the endosomal compartment (exosomes) or as a result of shedding from the plasma membrane (microvesicles, oncosomes and apoptotic bodies). Extracellular vesicles carry a variety of cargo, including RNAs, proteins, lipids and DNA, which can be taken up by other cells, both in the direct vicinity of the source cell and at distant sites in the body via biofluids, and elicit a variety of phenotypic responses. Owing to their unique biology and roles in cell-cell communication, extracellular vesicles have attracted strong interest, which is further enhanced by their potential clinical utility. Because extracellular vesicles derive their cargo from the contents of the cells that produce them, they are attractive sources of biomarkers for a variety of diseases. Furthermore, studies demonstrating phenotypic effects of specific extracellular vesicle-associated cargo on target cells have stoked interest in extracellular vesicles as therapeutic vehicles. There is particularly strong evidence that the RNA cargo of extracellular vesicles can alter recipient cell gene expression and function. During the past decade, extracellular vesicles and their RNA cargo have become better defined, but many aspects of extracellular vesicle biology remain to be elucidated. These include selective cargo loading resulting in substantial differences between the composition of extracellular vesicles and source cells; heterogeneity in extracellular vesicle size and composition; and undefined mechanisms for the uptake of extracellular vesicles into recipient cells and the fates of their cargo. Further progress in unravelling the basic mechanisms of extracellular vesicle biogenesis, transport, and cargo delivery and function is needed for successful clinical implementation. This Review focuses on the current state of knowledge pertaining to packaging, transport and function of RNAs in extracellular vesicles and outlines the progress made thus far towards their clinical applications
    corecore