1,325 research outputs found

    Conduct disorder : the achievement of a diagnosis'

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    This paper explores the historical shapings behind the diagnosis of conduct disorders. We take as our point of purchase oppositional ways of knowing the subject of conduct disorder—as either pathologically motivated or as the victim of a repressive mandate to control disorderly conduct. We take our cue from Foucault's suggestion that the pursuit of singular motivations behind a phenomenon is not the most fruitful means of understanding its historical appearance. We explore the emergence of the individual with conduct disorder as an appearance contingent upon dispersed agencies of government—an artefact of dispersed technologies for channelling and directing a population

    Probing Residue-Specific Interactions in the Stabilization of Proteins Using High-Resolution NMR: A Study of Disulfide Bond Compensation

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    It is well established that the oxidation state of cysteine residues in proteins are critical to overall physical stability. The presence of disulfide bonds most often imparts thermodynamic stability, and as such, engineered disulfide bonds have become a means for improving the viability of protein therapeutics. In some cases, however, disulfide bonds can diminish stability. Because proteins are held together by numerous weak interactions, understanding the mechanisms by which stabilization is achieved is important to the design of new biotechnology products that better resist unfolding and aggregation. Mechanistic information describing how specific interactions influence stability is lacking, in part because the techniques typically used to study inherent stability do not provide sufficient detail. In the present study, a model protein system, phosphatase of regenerating liver (PRL-1), was used to investigate the role of cysteine residues on physical stability. A combination of chemical modulation and mutagenesis was employed to alter the redox state of the protein, and the effects were observed using a combination of low- and high-resolution methods. Specifically, solution NMR data revealed the stability of PRL-1 depends on cooperation between local interactions with the Cys side chains. This approach provides a means to better understand how protein stabilization is achieved

    1H, 15N, 13C Resonance Assignments of the Reduced and Active Form of Human Protein Tyrosine Phosphatase, PRL-1

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    Phosphatase of regenerating liver-1 (PRL-1) is a novel target for potentially treating cancer metastases. Although its specific biochemical role in these processes has yet to be delineated, considerable evidence suggests the phosphatase activity of PRL-1 is required for promoting cancer and metastasis. PRL-1 belongs to the protein tyrosine phosphatase (PTPase) family and functions using the CX5R consensus active site motif. Like other PTPases, PRL-1 is inhibited by oxidation at its active site Cys, however, disulfide bond formation occurs unusually readily in wild-type PRL-1. Chemical shift assignments are available for oxidized wild type, but numerous, substantial changes are observed in the spectra upon reduction. Because the reduced form is active, we sought to identify a stable mutant that would resist oxidation and be useful for facilitating drug screening and development using NMR-based assays. We present here NMR assignments for a full-length, reduced and active form of PRL-1, PRL-1-C170S-C171S, that is well suited for this purpose

    Stability Analysis of an Inline Peptide-based Conjugate for Metal Delivery: Nickel(II)-claMP Tag Epidermal Growth Factor as a Model System

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    Metals are a key component of many diagnostic imaging and biotechnology applications, and the majority of cancer patients receive a platinum-based drug as part of their treatment. Significant effort has been devoted to developing tight binding synthetic chelators to enable effective targeted delivery of metal-based conjugates, with most successes involving lanthanides rather than transition metals for diagnostic imaging. Chemical conjugation modifies the protein’s properties and generates a heterogeneous mixture of products. Chelator attachment is typically done by converting the amino group on lysines to an amide, which can impact the stability and solubility of the targeting protein and these properties vary among the set of individual conjugate species. Site-specific attachment is sought to reduce complexity and control stability. Here, the metal abstraction peptide (MAP) technology was applied to create the claMP Tag, an inline platform for generating site-specific conjugates involving transition metals. The claMP Tag was genetically encoded into epidermal growth factor (EGF) and loaded with nickel(II) as a model system to demonstrate that the tag within the homogeneous inline conjugate presents sufficient solution stability to enable biotechnology applications. The structure and disulfide network of the protein and chemical stability of the claMP Tag and EGF components were characterized

    Founder\u27s Day Concert with Symphony Orchestra, Wind Ensemble and Men\u27s Ensemble

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    KSU School of Music presents Founder\u27s Day Concert with KSU Symphony Orchestra, Wind Ensemble and Men\u27s Ensemble featuring Leah Partridge, soprano.https://digitalcommons.kennesaw.edu/musicprograms/1282/thumbnail.jp

    Effects of Dusulfide Bond Formation and Protein Helicity on the Aggregation of Activating Transcription Factor 5 (ATF5)

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    Amorphous aggregation is a major problem for protein biopharmaceuticals, and aggregate formation in a drug formulation can have serious health implications for the patient. In many cases, an immunogenic response is generated from the administration of a drug product containing aggregated protein. This becomes especially significant when the patient requires long-term or repeated administration of the drug, because the likelihood of a severe immune response increases. While the prevention of protein aggregation is critically important for the future of protein pharmaceuticals, the process is still poorly understood. The lack of understanding regarding non-fibrillar aggregation is largely due to the fact that assembly is difficult to study. In particular the role that various structural features (i.e. α-helix, β-structure, disulfide bonds) play in the aggregation process varies with the amino acid sequence and is dependent upon tertiary structure and solution conditions. Well-structured proteins do not readily aggregate in solution, whereas partially unfolded proteins tend to aggregate rapidly and often become insoluble. Here, we present a unique and simple system for studying amorphous protein aggregation. We have previously reported the isolation of the basic leucine zipper (bZIP) domain of activating transcription factor 5 (ATF5), a protein notable for its potential as a pharmaceutical target for treatment of glioblastoma multiforme. This domain consists of a single α-helix and possesses a single cysteine residue. It is only partially structured and displays marginal stability in solution under physiological conditions. We have modulated solution conditions that affect backbone solubility and the oxidation state of the thiol to successfully investigate the role that α-helical structure and disulfide bond formation play in protein stability. Our data indicate that covalent cross-linking helps to retain ATF5’s helicity, which inhibits the formation of large aggregates. These studies have led to the identification of stabilizing conditions for ATF5, which will enable further study of the protein as a pharmaceutical target. Moreover, this work has general implications for analyzing stability of helical proteins in vitro and the specific atomic-level interactions in ATF5 that contribute to instability and self-association

    Evidence for sensitivity of dune wetlands to groundwater nutrients

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    Dune slacks are seasonal wetlands, high in biodiversity, which experience considerable within-year and between-year variations in water-table. They are subject to many pressures including climate change, land use change and eutrophication. Despite their biological importance and the threats facing them, the hydrological and nutrient parameters that influence their soil properties and biodiversity are poorly understood and there have been no empirical studies to date testing for biological effects in dune systems resulting from groundwater nutrients at low concentrations. In this study we examined the impact of groundwater nutrients on water chemistry, soil chemistry and vegetation composition of dune slacks at three distance classes (0-150 m, 150–300 m, 300–450 m) away from known (off-site) nutrient sources at Aberffraw dunes in North Wales, whilst controlling for differences in water-table regime. Groundwater nitrate and dissolved inorganic nitrogen (DIN) and soil nitrate and nitrite all had significantly higher concentrations closest to the nutrient source. Multivariate analysis showed that although plant species composition within this site was primarily controlled by water table depth and water table fluctuation, nitrogen from groundwater also influenced species composition, independently of water table and soil development. A model containing all hydrological parameters explained 17% of the total species variance; an additional 7% was explained following the addition of NO3 to this model. Areas exposed to elevated, but still relatively low, groundwater nutrient concentrations (mean 0.204 mg/L +/- 0.091 of DIN) had greater abundance of nitrophilous species and fewer basipholous species. This shows clear biological impact below previously suggested DIN thresholds of 0.20 – 0.40 (mg/L)

    Computer-Aided Detection of Pathologically Enlarged Lymph Nodes On Non-Contrast CT In Cervical Cancer Patients For Low-Resource Settings

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    The mortality rate of cervical cancer is approximately 266,000 people each year, and 70% of the burden occurs in Low- and Middle- Income Countries (LMICs). Radiation therapy is the primary modality for treatment of locally advanced cervical cancer cases. In the absence of high quality diagnostic imaging needed to identify nodal metastasis, many LMIC sites treat standard pelvic fields, failing to include node metastasis outside of the field and/or to boost lymph nodes in the abdomen and pelvis. The first goal of this project was to create a program which automatically identifies positive cervical cancer lymph nodes on non-contrast daily CT images, which are widely available in LMICs(1). A region of interest which is likely to contain the nodal volumes relevant for cervical cancer was defined on a single patient CT(2). This region was deformed onto new patients using an in-house, demons-based deformation software. Edge detection and erosion filtering were used to distinguish potential positive nodes from normal structures. Regions on adjacent slices were then connected into a potential nodal 3D-structure. To differentiate these 3D structures from normal tissues, eighty-six features were generated based on the shape and mean pixel values of the structures, and four classification ensemble methods were tested to differentiate the positive nodes from normal tissues. A cohort of fifty-eight MD Anderson cervical cancer patients with pathologically enlarged lymph nodes were used as a training-test set. Similarly, twenty MD Anderson cervical cancer patients were obtained as a validation set. They contained 154 and 35 pathologically enlarged lymph nodes, respectively. Model comparison led to the selection of the Adaboost ensemble model, utilizing 17 features. In the validation set, 60% of the clinically significant positive cervical cancer nodes were identified along with a false/true positive ratio of ~4:1. The entire process takes approximately 10/number-of-cores-minutes. Our findings demonstrated that our computer-aided detection model can assist in the identification of metastatic nodal disease where high quality diagnostic imaging is not readily available. By identifying these nodes, radiation treatment fields can be modified to include pathologically enlarged lymph nodes, which is an essential element to providing potentially curative radiotherapy for cervical cancer

    Determination of neutralization capacity and stability of a basic methacrylate monomer using NMR

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    This is an Accepted Manuscript of an article published by Taylor & Francis in International Journal of Polymeric Materials and Polymeric Biomaterials in 2012, available online: http://www.tandfonline.com/10.1080/00914037.2011.574660.The durability of dental resin depends on the stability of the polymer. The neutralizing capacity of a basic methacrylate monomer and its chemical stability were measured using nuclear magnetic resonance (NMR) spectroscopy. Lactic acid solution was titrated with 2-(dimethylamino)ethylmethacrylate (DMAEMA) or 2-hydroxyethylmethacrylate (HEMA) and its chemical shifts monitored. Addition of DMAEMA alters the chemical shift proportionally to pH neutralization, whereas HEMA has no impact. Chemical shifts were used to quantify both the change in pH and monomer stability. The results demonstrate that neutralization by basic monomer can be achieved and that this can be measured using an NMR assay
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