427 research outputs found
Framework and tool for rapid assessment of stream susceptibility to hydromodification
ABSTRACT: Changes in streamflow and sediment loading associated with urban development have the potential to exacerbate channel erosion, and result in impacts to wetland, riparian, and stream habitats, as well as infrastructure and property losses. The typical ''one-size-fits-all'' management prescription of flow control with retention or detention basins has not been wholly effective, pointing to a need for improved management strategies and tools for mitigating the impacts of ''hydromodification.'' We present an approach for developing screeninglevel tools for assessing channel susceptibility to hydromodification, and describe a novel tool for rapid, fieldbased assessments of the relative susceptibility of stream segments. The tool is based on the results of extensive field surveys, which indicate that susceptibility is the driver of channel response, not the magnitude of urbanization. A combination of relatively simple, but quantitative, field indicators are used as input parameters for a set of decision trees that follow a logical progression in assigning categorical susceptibility ratings to the channel segment being assessed. The susceptibility rating informs the level of data collection, modeling, and ultimate mitigation efforts that can be expected for a particular stream segment type. The screening approach represents a critical first step toward tailoring hydromodification management strategies and mitigation measures to different stream types and geomorphic settings
Identification of a Human Monoclonal Antibody to Replace Equine Diphtheria Anti-toxin for the Treatment of Diphtheria
Diphtheria anti-toxin (DAT) has been used to treat Corynebacterium diphtheriae infection for over one hundred years. While the global incidence of diphtheria has declined in the 20th century, the disease remains endemic in many parts of the world and significant outbreaks still occur. Diphtheria anti-toxin is an equine polyclonal antibody with considerable side effects that is in critically short supply globally. A safer, more readily available alternative to DAT would be desirable. In the current study, we cloned human monoclonal antibodies (HuMabs) directly from antibody secreting cells of human volunteers immunized with Td vaccine. We isolated a diverse panel of HuMabs that recognized diphtheria toxoid and recombinant protein fragments of diphtheria toxin. Forty-one unique HuMabs were expressed in 293T cells and tested for neutralization of diphtheria toxin in in vitro cytotoxicity assays. The lead candidate HuMab, 315C4 potently neutralized diphtheria toxin with an EC50 of 0.65 ng/mL. Additionally, 25 μg of 315C4 completely protected guinea pigs in an in vivo lethality model. In comparison, 1.6 IU of DAT was necessary for full protection resulting in an estimated relative potency of 64 IU/mg for 315C4. We further established that our lead candidate HuMab binds to the receptor binding domain of diphtheria toxin and blocks the toxin from binding to the putative receptor, heparin binding-epidermal growth factor like growth factor. The discovery of a specific and potent neutralizing antibody against diphtheria toxin holds promise as a potential human therapeutic and is being developed for human use
miR-34a Silences c-SRC to Attenuate Tumor Growth in Triple-Negative Breast Cancer
Triple-negative breast cancer (TNBC) is an aggressive subtype with no clinically proven biologically targeted treatment options. The molecular heterogeneity of TNBC and lack of high frequency driver mutations other than TP53 have hindered the development of new and effective therapies that significantly improve patient outcomes. miRNAs, global regulators of survival and proliferation pathways important in tumor development and maintenance, are becoming promising therapeutic agents. We performed miRNA-profiling studies in different TNBC subtypes to identify miRNAs that significantly contribute to disease progression. We found that miR-34a was lost in TNBC, specifically within mesenchymal and mesenchymal stem cell-like subtypes, whereas expression of miR-34a targets was significantly enriched. Furthermore, restoration of miR-34a in cell lines representing these subtypes inhibited proliferation and invasion, activated senescence, and promoted sensitivity to dasatinib by targeting the proto-oncogene c-SRC. Notably, SRC depletion in TNBC cell lines phenocopied the effects of miR-34a reintroduction, whereas SRC overexpression rescued the antitumorigenic properties mediated by miR-34a. miR-34a levels also increased when cells were treated with c-SRC inhibitors, suggesting a negative feedback exists between miR-34a and c-SRC. Moreover, miR-34a administration significantly delayed tumor growth of subcutaneously and orthotopically implanted tumors in nude mice, and was accompanied by c-SRC downregulation. Finally, we found that miR-34a and SRC levels were inversely correlated in human tumor specimens. Together, our results demonstrate that miR-34a exerts potent antitumorigenic effects in vitro and in vivo and suggests that miR-34a replacement therapy, which is currently being tested in human clinical trials, represents a promising therapeutic strategy for TNBC. Cancer Res; 76(4); 1-13. (c)2015 AACR
Reporting randomised trials of social and psychological interventions: the CONSORT-SPI 2018 Extension
Background:
Randomised controlled trials (RCTs) are used to evaluate social and psychological interventions and inform policy decisions about them. Accurate, complete, and transparent reports of social and psychological intervention RCTs are essential for understanding their design, conduct, results, and the implications of the findings. However, the reporting of RCTs of social and psychological interventions remains suboptimal. The CONSORT Statement has improved the reporting of RCTs in biomedicine. A similar high-quality guideline is needed for the behavioural and social sciences. Our objective was to develop an official extension of the Consolidated Standards of Reporting Trials 2010 Statement (CONSORT 2010) for reporting RCTs of social and psychological interventions: CONSORT-SPI 2018.
Methods:
We followed best practices in developing the reporting guideline extension. First, we conducted a systematic review of existing reporting guidelines. We then conducted an online Delphi process including 384 international participants. In March 2014, we held a 3-day consensus meeting of 31 experts to determine the content of a checklist specifically targeting social and psychological intervention RCTs. Experts discussed previous research and methodological issues of particular relevance to social and psychological intervention RCTs. They then voted on proposed modifications or extensions of items from CONSORT 2010.
Results:
The CONSORT-SPI 2018 checklist extends 9 of the 25 items from CONSORT 2010: background and objectives, trial design, participants, interventions, statistical methods, participant flow, baseline data, outcomes and estimation, and funding. In addition, participants added a new item related to stakeholder involvement, and they modified aspects of the flow diagram related to participant recruitment and retention.
Conclusions:
Authors should use CONSORT-SPI 2018 to improve reporting of their social and psychological intervention RCTs. Journals should revise editorial policies and procedures to require use of reporting guidelines by authors and peer reviewers to produce manuscripts that allow readers to appraise study quality, evaluate the applicability of findings to their contexts, and replicate effective interventions
Estrogen receptor-α and progesterone receptor are expressed in label-retaining mammary epithelial cells that divide asymmetrically and retain their template DNA strands
INTRODUCTION: Stem cells of somatic tissues are hypothesized to protect themselves from mutation and cancer risk through a process of selective segregation of their template DNA strands during asymmetric division. Mouse mammary epithelium contains label-retaining epithelial cells that divide asymmetrically and retain their template DNA. METHOD: Immunohistochemistry was used in murine mammary glands that had been labeled with [(3)H]thymidine during allometric growth to investigate the co-expression of DNA label retention and estrogen receptor (ER)-α or progesterone receptor (PR). Using the same methods, we investigated the co-localization of [(3)H]thymidine and ER-α or PR in mammary tissue from mice that had received treatment with estrogen, progesterone, and prolactin subsequent to a long chase period to identify label-retaining cells. RESULTS: Label-retaining epithelial cells (LRECs) comprised approximately 2.0% of the entire mammary epithelium. ER-α-positive and PR-positive cells represented about 30–40% of the LREC subpopulation. Administration of estrogen, progesterone, and prolactin altered the percentage of LRECs expressing ER-α. CONCLUSION: The results presented here support the premise that there is a subpopulation of LRECs in the murine mammary gland that is positive for ER-α and/or PR. This suggests that certain mammary LRECs (potentially stem cells) remain stably positive for these receptors, raising the possibility that LRECs comprise a hierarchy of asymmetrically cycling mammary stem/progenitor cells that are distinguished by the presence or absence of nuclear steroid receptor expression
Characterization of a Novel STAT 2 Knock Out Hamster Model of Crimean Congo Hemorrhagic Fever Virus Pathogenesis
Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne pathogen causing a febrile illness in humans, which can progress to hemorrhagic manifestations, multi-organ failure, and death. Current mouse models of CCHFV infection reliably succumb to virus challenge but vary in their ability to reflect signs of disease similar to humans. In this study, we established a signal transducer and activator of transcription 2 (STAT2) knockout hamster model to expand the repertoire of animal models of CCHFV pathogenesis that can be used for therapeutic development. These hamsters demonstrated a systemic and lethal disease in response to infection. Hallmarks of human disease were observed including petechial rash, blood coagulation dysfunction, and various biochemistry and blood cell count abnormalities. Furthermore, we also demonstrated the utility of this model for anti-CCHFV therapeutic evaluation. The STAT2 knock-out hamster model of CCHFV infection may provide some further insights into clinical disease, viral pathogenesis, and pave the way for testing of potential drug and vaccine candidates
Hadronic Electromagnetic Properties at Finite Lattice Spacing
Electromagnetic properties of the octet mesons as well as the octet and
decuplet baryons are augmented in quenched and partially quenched chiral
perturbation theory to include O(a) corrections due to lattice discretization.
We present the results for the SU(3) flavor group in the isospin limit as well
as the results for SU(2) flavor with non-degenerate quarks. These corrections
will be useful for extrapolation of lattice calculations using Wilson valence
and sea quarks, as well as calculations using Wilson sea quarks and
Ginsparg-Wilson valence quarks.Comment: 19 pages, 0 figures, RevTeX
Selective segregation of DNA strands persists in long label retaining mammary cells during pregnancy
Development of a high-throughput ex-vivo burn wound model using porcine skin, and its application to evaluate new approaches to control wound infection
Biofilm formation in wounds is considered a major barrier to successful treatment, and has been associated with the transition of wounds to a chronic non-healing state. Here, we present a novel laboratory model of wound biofilm formation using ex-vivo porcine skin and a custom burn wound array device. The model supports high-throughput studies of biofilm formation and is compatible with a range of established methods for monitoring bacterial growth, biofilm formation, and gene expression. We demonstrate the use of this model by evaluating the potential for bacteriophage to control biofilm formation by Staphylococcus aureus, and for population density dependant expression of S. aureus virulence factors (regulated by the Accessory Gene Regulator, agr) to signal clinically relevant wound infection. Enumeration of colony forming units and metabolic activity using the XTT assay, confirmed growth of bacteria in wounds and showed a significant reduction in viable cells after phage treatment. Confocal laser scanning microscopy confirmed the growth of biofilms in wounds, and showed phage treatment could significantly reduce the formation of these communities. Evaluation of agr activity by qRT-PCR showed an increase in activity during growth in wound models for most strains. Activation of a prototype infection-responsive dressing designed to provide a visual signal of wound infection, was related to increased agr activity. In all assays, excellent reproducibility was observed between replicates using this mode
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