1,943 research outputs found

    DIALECTICAL FOUNDATIONS OF SCIENTIFIC INQUIRY

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    The discovery in neurology that the two sides of the brain think in distinct ways that are both opposed to each other and complementary might have consequences in a number of academic disciplines, and in philosophy and political consciousness as well. It is the purpose of this paper to apply concepts from the brain theory to an analysis of the rational foundations of scientific inquiry. To pursue this argument, it is nnecessary to take a position on the side of materialism or idealism, although the theory certainly is related to that issue. And it should be made clear, at the outset, that we see no possibility that the explanation of ideas can be reduced to a physical theory such as physics.http://web.ku.edu/~starjrn

    Collagen-induced arthritis is exacerbated in IL-10-deficient mice

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    IL-10 is a potent immunoregulatory cytokine attenuating a wide range of immune effector and inflammatory responses. In the present study, we assess whether endogenous levels of IL-10 function to regulate the incidence and severity of collagen-induced arthritis. DBA/1 wildtype (WT), heterozygous (IL-10(+/-)) and homozygous (IL-10(-/-)) IL-10-deficient mice were immunized with type II collagen. Development of arthritis was monitored over time, and collagen-specific cytokine production and anticollagen antibodies were assessed. Arthritis developed progressively in mice immunized with collagen, and 100% of the WT, IL-10(+/-), and IL-10(-/-) mice were arthritic at 35 days. However, the severity of arthritis in the IL-10(-/-) mice was significantly greater than that in WT or IL-1(+/-) animals. Disease severity was associated with reduced IFN-γ levels and a dramatic increase in CD11b-positive macrophages. Paradoxically, both the IgG(1) and IgG(2a) anticollagen antibody responses were also significantly reduced. These data demonstrate that IL-10 is capable of controlling disease severity through a mechanism that involves IFN-γ. Since IL-10 levels are elevated in rheumatoid arthritis synovial fluid, these findings may have relevance to rheumatoid arthritis

    Adolescent Medicine at the Crossroads: A Review of Fellowship Training and Recommendations for Reform

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    This report examines the current state of adolescent medicine fellowship programs -- including the supply and recruitment of fellows; the nature and content of clinical, research, and leadership training; and the institutional and financial challenges facing training programs today -- and offers recommendations for building the field. The report is based on findings from the first comprehensive national survey of adolescent medicine fellowship program directors, conducted in the spring of 2007 by Incenter Strategies. The document also presents selected findings from two other Incenter Strategies’ surveys conducted in 2007: one of pediatric residency program directors and the other of adolescent medicine faculty responsible for the one-month pediatric residency rotation. In addition, the report presents findings from key informant interviews and an extensive literature review

    Cultural Competence as a Response to Structural Racism in Latino Substance Use and Access to Care in the United States

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    Disparities in substance use disorders (SUD) and access to treatment among individuals identified as Latino/Hispanic have become a significant public health issue in the United States. National efforts to identify, understand, and eliminate such disparities have highlighted the role of structural racism in Latino health. In this chapter, we offer a critical review of how Latino substance use and access to care may be impacted by discrimination, acculturation stress, and other mechanisms of structural racism. As structural racism is represented by policies, systems, structures, and norms that deny and/or minimize cultural strengths and disempower culturally diverse groups and their attempts to invest in their wellness, we highlight how cultural competence may reduce the risk of SUD and may enhance access to treatment among Latinos. We conclude by highlighting policies and responsive organizational practices that may improve Latino health

    DHODH modulates transcriptional elongation in the neural crest and melanoma

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    Melanoma is a tumour of transformed melanocytes, which are originally derived from the embryonic neural crest. It is unknown to what extent the programs that regulate neural crest development interact with mutations in the BRAF oncogene, which is the most commonly mutated gene in human melanoma1. We have used zebrafish embryos to identify the initiating transcriptional events that occur on activation of human BRAF(V600E) (which encodes an amino acid substitution mutant of BRAF) in the neural crest lineage. Zebrafish embryos that are transgenic for mitfa:BRAF(V600E) and lack p53 (also known as tp53) have a gene signature that is enriched for markers of multipotent neural crest cells, and neural crest progenitors from these embryos fail to terminally differentiate. To determine whether these early transcriptional events are important for melanoma pathogenesis, we performed a chemical genetic screen to identify small-molecule suppressors of the neural crest lineage, which were then tested for their effects on melanoma. One class of compound, inhibitors of dihydroorotate dehydrogenase (DHODH), for example leflunomide, led to an almost complete abrogation of neural crest development in zebrafish and to a reduction in the self-renewal of mammalian neural crest stem cells. Leflunomide exerts these effects by inhibiting the transcriptional elongation of genes that are required for neural crest development and melanoma growth. When used alone or in combination with a specific inhibitor of the BRAF(V600E) oncogene, DHODH inhibition led to a marked decrease in melanoma growth both in vitro and in mouse xenograft studies. Taken together, these studies highlight developmental pathways in neural crest cells that have a direct bearing on melanoma formation

    DNM1 encephalopathy: A new disease of vesicle fission.

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    ObjectiveTo evaluate the phenotypic spectrum caused by mutations in dynamin 1 (DNM1), encoding the presynaptic protein DNM1, and to investigate possible genotype-phenotype correlations and predicted functional consequences based on structural modeling.MethodsWe reviewed phenotypic data of 21 patients (7 previously published) with DNM1 mutations. We compared mutation data to known functional data and undertook biomolecular modeling to assess the effect of the mutations on protein function.ResultsWe identified 19 patients with de novo mutations in DNM1 and a sibling pair who had an inherited mutation from a mosaic parent. Seven patients (33.3%) carried the recurrent p.Arg237Trp mutation. A common phenotype emerged that included severe to profound intellectual disability and muscular hypotonia in all patients and an epilepsy characterized by infantile spasms in 16 of 21 patients, frequently evolving into Lennox-Gastaut syndrome. Two patients had profound global developmental delay without seizures. In addition, we describe a single patient with normal development before the onset of a catastrophic epilepsy, consistent with febrile infection-related epilepsy syndrome at 4 years. All mutations cluster within the GTPase or middle domains, and structural modeling and existing functional data suggest a dominant-negative effect on DMN1 function.ConclusionsThe phenotypic spectrum of DNM1-related encephalopathy is relatively homogeneous, in contrast to many other genetic epilepsies. Up to one-third of patients carry the recurrent p.Arg237Trp variant, which is now one of the most common recurrent variants in epileptic encephalopathies identified to date. Given the predicted dominant-negative mechanism of this mutation, this variant presents a prime target for therapeutic intervention

    Human NKp44+IL-22+ cells and LTi-like cells constitute a stable RORC+ lineage distinct from conventional natural killer cells

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    Lymphoid tissue inducer (LTi) cells are required for lymph node formation during fetal development, and recent evidence implies a role in mucosal immunity in the adult. LTi cells share some phenotypic features of conventional natural killer (NK; cNK) cells; however, little is known to date about the relationship between these two cell types. We show that lineage− (Lin−) CD127+RORC+ LTi-like cells in human tonsil are precursors to CD56+CD127+RORC+NKp46+ cells, which together comprise a stable RORC+ lineage. We find that LTi-like cells and their CD56+ progeny can be expanded and cloned ex vivo without loss of function and without conversion into cNK cells. Clonal analysis reveals heterogeneity of cytokine production within the CD127+ LTi-like population. Furthermore, we identify within the tonsil a cNK precursor population that is characterized as Lin−CD117+CD161+CD127− cells. Overall, we propose that CD127+RORC+ cells, although they share some characteristics with cNK cells, represent a functionally and developmentally distinct lineage

    Gravito-electromagnetic analogies

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    We reexamine and further develop different gravito-electromagnetic (GEM) analogies found in the literature, and clarify the connection between them. Special emphasis is placed in two exact physical analogies: the analogy based on inertial fields from the so-called "1+3 formalism", and the analogy based on tidal tensors. Both are reformulated, extended and generalized. We write in both formalisms the Maxwell and the full exact Einstein field equations with sources, plus the algebraic Bianchi identities, which are cast as the source-free equations for the gravitational field. New results within each approach are unveiled. The well known analogy between linearized gravity and electromagnetism in Lorentz frames is obtained as a limiting case of the exact ones. The formal analogies between the Maxwell and Weyl tensors are also discussed, and, together with insight from the other approaches, used to physically interpret gravitational radiation. The precise conditions under which a similarity between gravity and electromagnetism occurs are discussed, and we conclude by summarizing the main outcome of each approach.Comment: 60 pages, 2 figures. Improved version (compared to v2) with some re-write, notation improvements and a new figure that match the published version; expanded compared to the published version to include Secs. 2.3 and
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