2,971 research outputs found

    An agent based simulation of the dynamics in cognitive depressogenic thought

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    Depression is a common mental disorder. Appropriate support from others can reduce the cognitive distortion that can be caused by subsequent depressions.To increase our understanding of this process, an agent model is presented in this paper in which the positive and negative effects of social support and its relation with cognitive thoughts are modelled. Simulations show the effect of social support on different personality types.A mathematical analysis of the stable situations in the model gives an additional explanation of extreme cases. Finally, a formal verification of expect ed relations between support, risk factors and depressive thoughts is performed on the simulation traces to check whether the simulations describe realistic processes

    Engineering Antibodies to Enhance Activity and Increase Half-life

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    Background: HIV/AIDS remains one of the most serious current threats to global public health. Although anti-HIV drugs have been effective among the wealthiest populations, a vaccine and/or new methods to prevent infections are needed lo control HIV globally. Strategies to combat HIV-1 require structural knowledge of how antibodies recognize HIV envelope proteins and how the immune system eliminates viruses. Until recently, only a small number of broadly neutralizing antibodies against HIV-1 had been characterized, and the immunological basis for their breadth and potency remains poorly understood. However. it was recently demonstrated that antibodies could be engineered to greatly enhance their breadth and potency (Diskin et al., Science 2011). Unfortunately, this and other engineering efforts have resulted in a decrease in antibody half-life in mouse and non-human primate models. This decrease in half-life correlates with an increase in reactivity to a variety of antigens, termed polyreactivity. Methods: In order to make better targets for passive delivery therapies, we are working to increase the half-life of antibodies while maintaining their breadth and potency using a variety of computational and structured-based techniques. One technique involves reducing the spatial aggregation propensity, in which an algorithm finds dynamically exposed hydrophobic patches on the surlace of proteins (Chemansetty et al., PNAS 2009). To this end, we have constructed several mutations in regions that have been predicted to have high aggregation propensities, and have tested them for polyreactivity and potency in neutralization assays. Results: Initial results show that these novel reagents have reduced polyreactivily, yet they still maintain their potency in in vitro neutralization assays. Conclusions: We are currently pursuing in vivo experiments in mice to further understand the relationship between antibody potency, polyreactivity, and half-life

    Simulating cognitive coping strategies for intelligent support agents

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    People react differently to stress.According to the Cognitive Motivational Relational Theory by Lazarus and Folkman, the appraisal of stress and the emotions related to it determine whether people cope with stress by focusing on altering the situation (problem focused) or on changing the emotional consequences of the events (emotion focused). These different coping strategies have different effects on the long term.The coping process can be described in a formal dynamic model. Simulations using this model show that problem focused coping leads to better coping skills and higher decrease of long-term stress than emotion focused coping.These results also follow from a mathematical analysis of the model.The presented model can form the basis of an intelligent support system that uses a simulation of cognitive processes in humans in stressful conditions

    Relationship between intact HIV-1 proviruses in circulating CD4+ T cells and rebound viruses emerging during treatment interruption.

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    Combination antiretroviral therapy controls but does not cure HIV-1 infection because a small fraction of cells harbor latent viruses that can produce rebound viremia when therapy is interrupted. The circulating latent virus reservoir has been documented by a variety of methods, most prominently by viral outgrowth assays (VOAs) in which CD4+ T cells are activated to produce virus in vitro, or more recently by amplifying proviral near full-length (NFL) sequences from DNA. Analysis of samples obtained in clinical studies in which individuals underwent analytical treatment interruption (ATI), showed little if any overlap between circulating latent viruses obtained from outgrowth cultures and rebound viruses from plasma. To determine whether intact proviruses amplified from DNA are more closely related to rebound viruses than those obtained from VOAs, we assayed 12 individuals who underwent ATI after infusion of a combination of two monoclonal anti-HIV-1 antibodies. A total of 435 intact proviruses obtained by NFL sequencing were compared with 650 latent viruses from VOAs and 246 plasma rebound viruses. Although, intact NFL and outgrowth culture sequences showed similar levels of stability and diversity with 39% overlap, the size of the reservoir estimated from NFL sequencing was larger than and did not correlate with VOAs. Finally, intact proviruses documented by NFL sequencing showed no sequence overlap with rebound viruses; however, they appear to contribute to recombinant viruses found in plasma during rebound

    From maltreatment to psychiatric disorders in childhood and adolescence: The relevance of emotional maltreatment

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    Different forms of maltreatment are thought to incur a cumulative and non-specific toll on mental health. However, few large-scale studies draw on psychiatric diagnoses manifesting in early childhood and adolescence to identify sequelae of differential maltreatment exposures, and emotional maltreatment, in particular. Fine-grained multi-source dimensional maltreatment assessments and validated age-appropriate clinical interviews were conducted in a sample of N = 778 3 to 16-year-olds. We aimed to (a) substantiate known patterns of clinical outcomes following maltreatment and (b) analyse relative effects of emotional maltreatment, abuse (physical and sexual), and neglect (physical, supervisory, and moral-legal/educational) using structural equation modeling. Besides confirming known relationships between maltreatment exposures and psychiatric disorders, emotional maltreatment exerted particularly strong effects on internalizing disorders in older youth and externalizing disorders in younger children, accounting for variance over and above abuse and neglect exposures. Our data highlight the toxicity of pathogenic relational experiences from early childhood onwards, urging researchers and practitioners alike to prioritize future work on emotional maltreatment

    Restricting HIV-1 pathways for escape using rationally designed anti–HIV-1 antibodies

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    Recently identified broadly neutralizing antibodies (bNAbs) that potently neutralize most HIV-1 strains are key to potential antibody-based therapeutic approaches to combat HIV/AIDS in the absence of an effective vaccine. Increasing bNAb potencies and resistance to common routes of HIV-1 escape through mutation would facilitate their use as therapeutics. We previously used structure-based design to create the bNAb NIH45-46G54W, which exhibits superior potency and/or breadth compared with other bNAbs. We report new, more effective NIH45-46^(G54W) variants designed using analyses of the NIH45-46–gp120 complex structure and sequences of NIH45-46^(G54W)–resistant HIV-1 strains. One variant, 45-46m2, neutralizes 96% of HIV-1 strains in a cross-clade panel and viruses isolated from an HIV-infected individual that are resistant to all other known bNAbs, making it the single most broad and potent anti–HIV-1 antibody to date. A description of its mechanism is presented based on a 45-46m2–gp120 crystal structure. A second variant, 45-46m7, designed to thwart HIV-1 resistance to NIH45-46G54W arising from mutations in a gp120 consensus sequence, targets a common route of HIV-1 escape. In combination, 45-46m2 and 45-46m7 reduce the possible routes for the evolution of fit viral escape mutants in HIV-1_(YU-2)–infected humanized mice, with viremic control exhibited when a third antibody, 10–1074, was added to the combination

    Political Branding: The Tea Party and Its Use of Participation Branding

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    The emergence of the Tea Party movement in 2009 witnessed the surfacing of a populist, anti-Obama libertarian mobilization within the United States. The Tea Party, a movement that brought together a number of disparate groups—some new, some established—utilized participation branding where the consumer attributed the movement its own identity and brand. Its consumer-facing approach, lack of one single leader, and lack of a detailed party platform, in combination with its impact on the 2010 election races in America, earmarks it as a contemporary and unconventional brand phenomenon worthy of investigation. Copyright © Taylor & Francis Group, LLC

    Causes of early death and treatment-related death in newly diagnosed pediatric acute myeloid leukemia:Recent experiences of the Dutch Childhood Oncology Group

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    Background: With the current more effective treatment regimens for pediatric acute myeloid leukemia (AML), research on early death (ED), treatment-related mortality (TRM), and toxicity becomes increasingly important. The aim of this study was to give an overview of the frequency, clinical features, and risk factors associated with ED and TRM in first complete remission (CR1) during the last three consecutive treatment protocols of the Dutch Childhood Oncology Group (DCOG) between 1998 and 2014. Methods: Incidence and risk factors associated with ED and TRM in CR1 were retrospectively studied in 245 patients treated according to the Dutch ANLL-97/AML-12 (n = 118), AML-15 (n = 60), or DB AML-01 (n = 67) protocols. Results: The incidence of ED was, respectively, 5.1%, 6.7%, and 3.0% excluding deaths before treatment (P = NS), and 7.4%, 11.1%, and 4.4% including deaths before the onset of treatment. Severe underweight at initial diagnosis was significantly associated with more frequent ED. When relapse was included as a competing risk, cumulative incidence of death in CR1 were 5.9%, 5.0%, and 4.6% for ANLL97, AML15, and DB01, respectively (P = NS). The most important cause of TRM included infectious and SCT-related complications. Conclusion: We report relatively stable rates of ED and TRM in CR1 in the latest completed DCOG protocols for newly diagnosed AML patients. The most important causes of TRM were SCT- or infection-related, warranting further evaluation and awareness
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