855 resultados para Critical whiteness studies
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Critical situations (CSs) involving football fans is a well-researched phenomenon with most studies examining factors leading to an escalation of violence (e.g. Braun & Vliegenthart, 2008). However, research so far has fallen short of analysing CSs that do not escalate (e.g. Hylander & Guvå, 2010) as well as establishing observable criteria that constitute such CSs. Granström et al. (2009), for instance, put forward a definition of a CS describing such situations as characterised by a discrepancy between peace and war-making behaviours between police and demonstrators. Still, this definition remains vague and does not provide concrete, defining criteria that can be identified on site. The present study looks beyond fans’ violent acts per se and focuses on these situations with a potentially – but not necessarily - violent outcome. The aim of this preliminary study is to identify observable criteria defining such a CS involving football fans. This focus group comprised of five experts working with football fans in the German-speaking area of Switzerland who discussed observable characteristics of a CS. Inductive content analysis led to the identification of specific criteria such as, “arrest of a fan”, “insufficient distance (<30m) between fans and police” and “fans mask themselves”. These criteria were then assigned to four phases of a CS highlighting the dynamic aspect of this phenomenon: Antecedents, Causes, Reactions, Consequence. Specifically, Causes, Reactions and Consequences are observable on site, while Antecedents include relevant, background information directly influencing a CS. This study puts forward a working definition of a CS that can facilitate the assessment of actual situations in the football context as well as for further research on fan violence prevention and control. These results also highlight similarities with studies investigating fan violence in other European countries while acknowledging unique characteristics of the Swiss German fan culture.
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OBJECTIVES: To (1) review the development and medical applications of hydroxyethyl starch (HES) solutions with particular emphasis on its physiochemical properties; (2) critically appraise the available evidence in human and veterinary medicine, and (3) evaluate the potential risks and benefits associated with their use in critically ill small animals. DATA SOURCES: Human and veterinary original research articles, scientific reviews, and textbook sources from 1950 to the present. HUMAN DATA SYNTHESIS: HES solutions have been used extensively in people for over 30 years and ever since its introduction there has been a great deal of debate over its safety and efficacy. Recently, results of seminal trials and meta-analyses showing increased risks related to kidney dysfunction and mortality in septic and critically ill patients, have led to the restriction of HES use in these patient populations by European regulatory authorities. Although the initial ban on the use of HES in Europe has been eased, proof regarding the benefits and safety profile of HES in trauma and surgical patient populations has been requested by these same European regulatory authorities. VETERINARY DATA SYNTHESIS: The veterinary literature is limited mostly to experimental studies and clinical investigations with small populations of patients with short-term end points and there is insufficient evidence to generate recommendations. CONCLUSIONS: Currently, there are no consensus recommendations regarding the use of HES in veterinary medicine. Veterinarians and institutions affected by the HES restrictions have had to critically reassess the risks and benefits related to HES usage based on the available information and sometimes adapt their procedures and policies based on their reassessment. Meanwhile, large, prospective, randomized veterinary studies evaluating HES use are needed to achieve relevant levels of evidence to enable formulation of specific veterinary guidelines.
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This study attempts a critical evaluation of the clinical evidence behind the use of dietary pomegranate preparations in the prevention and treatment of cardiovascular diseases. A search of PubMed on August 10, 2014 identified 228 references, which yielded extractable data from 24 clinical studies of pomegranate preparations. Hand searching identified two further studies. The quality of the studies and evidence of effectiveness of pomegranate were assessed by an established set of conventional criteria. Overall, the study quality was poor. Even in the best studies, indications of benefit did not reach the conventional levels of statistical significance. The only study with a definitive design had a biochemical rather than a clinical endpoint: it showed the expected difference in blood concentrations of myeloperoxidase after a single dose of either pomegranate or placebo. Only 10 of the 26 studies provided HPLC data on the amounts of co-active ingredients in the preparations that were consumed by the subjects. If pomegranate has a role in the prevention and treatment of cardiovascular diseases, there is a pressing need for dose-finding and long-term confirmatory studies. The ultimate endpoint for definitive studies would be mortality, but reductions in blood pressure or demonstrable decreases in atherosclerotic plaques would be useful surrogates. Sample sizes for various assumptions are provided. Future studies need to prove the clinical benefit.
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This study examines incidents involving a tense atmosphere combined with higher risk of football fan violence. A systematic description of such critical incidents (CIs) identifying their risk factors and warning signs is yet lacking. This study looks beyond fans’ violent acts per se and focuses on CIs involving ultra fans with a potentially – but not necessarily – violent outcome. A preliminary study involving a focus group was conducted followed by a main study including eight case studies. The focus group comprised five professionals working with football fans who discussed CIs’ observable characteristics. Risk factors and warning signs were coded using content analysis, such as, ‘arrest of a fan’. In the main study, people involved in actual CIs were interviewed to explore these phenomena in more depth. An integrated model of CIs’ dynamics, risk factors and warning signs was compiled using data gathered in both studies.
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During T cell dependent immune responses, the acquisition of B cell memory from naïve cells takes place within a highly specialized microenvironment: The germinal centers (GC) of the secondary lymphoid organs. The GC reaction is a tightly regulated process in which the balance between survival and death is mediated by signals transduced through ligation of critical costimulatory molecules such as CD40 and CD154. While most cognate receptor-ligand interactions occur between T-cells and antigen (Ag)-presenting cells (APC) such as B-cells, evidence of homotypic B cell interactions has emerged. Despite the progress in our understanding of the reaction, several questions remain: (1) What determines the concomitant expression of CD40 and its ligand CD154 by GC B-cells? (2) Which molecules are responsible for inducing GC-B cell survival? and (3) how can cognate T-cell help be recruited into the organized structure of GCs? ^ Because the expression of costimulatory and survival molecules is predominant at distinct Ag-dependent maturation stages, we hypothesized the existence of stage specific gene expression responsible for the regulation of the GC reaction. Our studies reveal several novel genes whose expression may be critical for the GC reaction. The discovery of AKNA reveals the mechanism behind homotypic B cell CD40 and CD40 ligand interactions, which can explain the costimulatory signaling to GC B cells in the absence of T cells. Additionally, the identification of the pro-survival molecule PRELI may provide a novel mechanism for the survival of Ag-selected B cells. We propose that PRELI and its phylogenic homologues represent a novel family of proteins responsible for the protection of cells against caspase-independent apoptosis. Furthermore, we show that GC B cells actively participate in the recruitment of T cells through the secretion of CC and CxC chemokines, thus supporting their mutual involvement in cognate interactions. ^
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This thesis analyzes the sportswriting genre as a form of personal essay. It explores the art over time through writers Red Smith, A.J. Liebling, Roger Angell, George Plimpton, Bart Giamatti, Frank Deford, and Rick Reilly, as well as anthologized writers from 2008 and blogs.
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The central dogma of molecular biology dictates that DNA is transcribed into RNA, which is later translated into protein. One of the early activators in this process is the transcription factor NF-κB. We have determined that an NF-κB inducer, CARMA3, is required for proper neural tube closure, similar to other NF-κB inducers. Using a genetic knockout of CARMA3, we demonstrated that it is required for Gαq-coupled GPCR-induced NF-κB activation. This is facilitated through a MAPK and IKK phosphorylation-independent mechanism, most likely by controlling NEMO-associated ubiquitination. We have also shown that CARMA3 is required for EGF and HRG-induced NF-κB activation. This activation requires the activity of both EGFR and HER2, as well as PKC. Again, we observed no defect in IKK phosphorylation, although we determined a clear defect in IKK activation. Finally, we have begun to determine the role of CARMA3 to both EGFR and HER2-induced tumorigenicity. By overexpressing a constitutive active mutant of HER2 in our CARMA3 WT and KO MEF cells, we have shown CARMA3 is important for HER2-driven soft agar colony growth. We have also shown that knockdown of endogenous CARMA3 in the EGFR-overexpressing A431 cell line abolishes EGF-induced NF-κB activation. These same cells have a dramatically reduced capacity to form colonies in soft agar as well. Using both mouse xenografts and a transgenic model of HER2-induced breast cancer, we have initiated studies which will help to determine the role of CARMA3 to in vivo tumorigenesis. Collectively, this work reveals novel roles for the CARMA3 protein in development, GPCR and EGFR/HER2 signaling. It also suggests that CARMA3 is involved in EGFR/HER2 mediated tumorigenesis, possibly indicating a novel therapeutic target for use in treatment of cancer. ^
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Background. Because it is important to minimize children's sun exposure to reduce skin cancer risk, much of the extensive skin cancer prevention literature consists of studies of children's sun protection, sun avoidance and ultraviolet radiation (UVR) exposure. Little attention has been focused on the measurement of psychosocial constructs in these studies. Identification of the psychosocial correlates or determinants of children's skin cancer risk or risk-reduction behavior is critical to more fully understand and predict behavior. Furthermore, psychosocial variables may be influenced by interventions to reduce risk. Thus, it is important to examine the psychosocial measures used in studies of children's skin cancer prevention. Information on the validity and reliability of psychosocial measures may increase confidence in study findings based on these measures. In particular, self-efficacy and barriers are key constructs in several major theoretical frameworks and parental measures have been associated with children's sun protection. However, there is conceptual overlap of self-efficacy and barriers measures and little is known about the psychometric properties of these measures.^ Study Aims and Methods. The overall goal of this dissertation was to examine the measurement of psychosocial constructs relevant to children's skin cancer prevention. Because children depend primarily on their parents for skin cancer prevention, measures of parents' psychosocial constructs are the focus. Study 1 was a systematic review of parental psychosocial measures used in studies of children's sun protection, sun avoidance and UVR exposure. The specific aims of Study 1 were to (1) describe psychosocial measures reported by parents, including available information on the psychometric properties of these measures and their use in analyses and (2) provide recommendations for the development, refinement and standardized reporting of measures. ^ Study 2 examined the psychometric properties of measures of parental self-efficacy and barriers regarding children's sun protection. Melanoma patients (N=205) who were parents of children ≤ 12 years of age completed a telephone interview that included self-efficacy and barriers measures specific to sunscreen, clothing, shade and limiting time outdoors. The specific aims of Study 2 were to (1) use a confirmatory factor analytic approach to examine the factorial validity of parental self-efficacy and barriers measures, (2) examine the convergent and discriminant validity of behavior-specific measures of self-efficacy and barriers and (3) assess the reliability of item and scale measures.^ Results. In Study 1, a search of standard databases yielded 48 eligible studies. Most studies assessed only one or two psychosocial constructs. Knowledge was measured most frequently. There was little discussion of measure source, development, theoretical background or psychometric properties, besides internal consistency reliability. There was conceptual overlap of some measures. In Study 2, confirmatory factor analytic findings supported the factorial validity of the self-efficacy and barriers measures. When all eight self-efficacy and barriers measures were included in the same model, a modified eight-factor model adequately fit the data, providing preliminary evidence that the measures are distinct. Measure associations supported the convergent validity of all measures and the discriminant validity of most measures. The self-efficacy and barriers measures were reliable.^ Conclusions. Recommendations based on the literature review include developing and refining psychosocial measures based on theory. Describing a measure's theoretical basis and psychometric properties would facilitate critical evaluation. Standardized reporting of source, development, theory, construct, items and analytic role would facilitate comparison of findings, continual refinement and future applications of measures. In the validation study, self-efficacy and barriers measures were examined in a sample of parents with a personal history of melanoma. Findings suggested that these measures are valid and reliable for use in studies of children's sun protection. There was preliminary evidence that these measures are distinct but additional study is needed. ^
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One of the most critical aspects of G Protein Coupled Receptors (GPCRs) regulation is their rapid and acute desensitization following agonist stimulation. Phosphorylation of these receptors by GPCR kinases (GRK) is a major mechanism of desensitization. Considerable evidence from studies of rhodopsin kinase and GRK2 suggests there is an allosteric docking site for the receptor distinct from the GRK catalytic site. While the agonist-activated GPCR appears crucial for GRK activation, the molecular details of this interaction remain unclear. Recent studies suggested an important role for the N- and C-termini and domains in the small lobe of the kinase domain in allosteric activation; however, neither the mechanism of action of that site nor the RH domain contributions have been elucidated. To search for the allosteric site, we first indentified evolutionarily conserved sites within the RH and kinase domains presumably deterministic of protein function employing evolutionary trace (ET) methodology and crystal structures of GRK6. Focusing on a conserved cluster centered on helices 3, 9, and 10 in the RH domain, key residues of GRK5 and 6 were targeted for mutagenesis and functional assays. We found that a number of double mutations within helices 3, 9, and 10 and the N-terminus markedly reduced (50–90%) the constitutive phosphorylation of the β-2 Adrenergic Receptor (β2AR) in intact cells and phosphorylation of light-activated rhodopsin (Rho*) in vitro as compared to wild type (WT) GRK5 or 6. Based on these results, we designed peptide mimetics of GRK5 helix 9 both computationally and through chemical modifications with the goal of both confirming the importance of helix 9 and developing a useful inhibitor to disrupt the GPCR-GRK interaction. Several peptides were found to block Rho* phosphorylation by GRK5 including the native helix 9 sequence, Peptide Builder designed-peptide preserving only the key ET residues, and chemically locked helices. Most peptidomimetics showed inhibition of GRK5 activity greater than 80 % with an IC50 of ∼ 30 µM. Alanine scanning of helix 9 has further revealed both essential and non-essential residues for inhibition. Importantly, substitution of Arg 169 by an alanine in the native helix 9-based peptide gave an almost complete inhibition at 30 µM with an IC50 of ∼ 10 µM. In summary we report a previously unrecognized crucial role for the RH domain of GRK5 and 6, and the subsequent identification of a lead peptide inhibitor of protein-protein interaction with potential for specific blockade of GPCR desensitization. ^
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The presentation of MHC class I (MHC-I)/peptide complexes by dendritic cells (DCs) is critical for the maintenance of central tolerance to self and for the regulation of cytotoxic T lymphocytes (CTL)-mediated adaptive immune responses against pathogens and cancer cells. Interestingly, several findings have suggested that the cytoplasmic tail of MHC class I plays a functional role in the regulation of CTL immune responses. For example, our previous studies demonstrated that exon 7-deleted MHC-I molecules not only showed extended DC cell surface half-lives but also induced significantly increased CTL responses to viral challange invivo. Although exon 7-deleted variant of MHC-I does not occur naturally in humans, the animal studies prompted us to examine whether exon 7-deleted MHC-I molecules could generate augmented CTL responses in a therapeutic DC-based vaccine setting. To examine the stimulatory capacity of exon 7-deleted MHC-I molecules, we generated a lentivirus-mediated gene transfer system to induce the expression of different MHC-I cytoplasmic tail isoforms in both mouse and human DCs. These DCs were then used as vaccines in a melanoma mouse tumor model and in a human invitro co-culture system. In this thesis, we show that DCs expressing exon 7-deleted MHC-I molecules, stimulated remarkably higher levels of T-cell cytokine production and significantly increased the proliferation of meanoma-specific (Pmel-1) T cells compared with DCs expressing wild type MHC-I. We also demonstrate that, in combination with adoptive transfer of Pmel-1 T-cell, DCs expressing exon 7-deleted Db molecules induced greater anti-tumor responses against established B16 melanoma tumors, significantly extending mouse survival as compared to DCs expressing wild-type Db molecules. Moreover, we also observed that human DCs expressing exon 7-deleted HLA-A2 molecules showed similarly augmented CTL stimulatory ability. Mechanistic studies suggest that exon 7-deleted MHC-I molecules showed impaired lateral membrane movement and extended cell surface half-lives within the DC/T-cell interface, leading to increased spatial availability of MHC-I/peptide complexes for recognition by CD8+ T cells. Collectively, these results suggesr that targeting exon 7 within the cytoplasmic tail of MHC-I molecules in DC vaccines has the potential to enhance CD8+ T cell stimulatory capacity and improve clinical outcomes in patients with cancer or viral infections.
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A fundamental task in developmental biology is to understand the molecular mechanisms governing early embryogenesis. The aim of this study was to understand the developmental role of a putative basic helix-loop-helix (b-HLH) transcription factor, twist, during mouse embryogenesis.^ twist was originally identified in Drosophila as one of the zygotic genes, including snail, that were required for dorsal-ventral patterning. In Drosophila embryogenesis, twist is expressed in the cells of the ventral midline destined to form mesoderm. In embryos lacking twist expression, their ventral cells fail to form a ventral furrow and subsequently no mesoderm is formed.^ During mouse embryogenesis, twist is expressed after initial mesoderm formation in both mesoderm and cranial neural crest cell derivatives. To study the role of twist in vivo, twist-null embryos were generated by gene targeting. Embryos homozygous for the twist mutation die at midgestation. The most prominent phenotype in the present study was a failure of the cranial neural tube to close (exencephaly). twist-null embryos also showed defects in head mesenchyme, branchial arches, somites, and limb buds.^ To understand whether twist functions cell-autonomously and to investigate how twist-null cells interact with wild-type cells in vivo, twist chimeras composed of both twist-null and wild-type cells marked by the expression of the lacZgene were generated. Chimeric analysis revealed a correlation between the incidence of exencephaly and the contribution of the underlying twist-null head mesenchyme, thus strongly suggesting that twist-expressing head mesenchyme is required for the closure of the cranial neural tube. These studies have identified twist as a critical regulator for the mesenchymal fate determination within the cranial neural crest lineage. Most strikingly, twist-null head mesenchyme cells were always segregated from wild-type cells, indicating that the twist mutation altered the adhesive specificity of these cells. Furthermore, these results also indicated that twist functions cell-autonomously in the head, arch, and limb mesenchyme but non-cell-autonomously in the somites. Taken together, these studies have established the essential role of twist during mouse embryogenesis. ^
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In various species, peripheral injury produces long-lasting sensitization of central and peripheral neurons representing the affected area. In Aplysia, memory-like traces (lasting days or weeks) of noxious peripheral stimulation include enhancement of central synaptic transmission and enhanced excitability of the central soma and peripheral branches of nociceptive sensory neurons. An important role for the cAMP-PKA-CREB pathway in consolidating long-term memory and inducing transcription-dependent synaptic potentiation has also been indicated by studies in rodents and Drosophila. ^ Much less attention has been paid to the cGMP-PKG pathway for transcription-dependent plasticity. Nevertheless, the cGMP-PKG pathway has been implicated in activity-dependent neural alterations lasting hours, and may trigger some forms of persistent pain. Recent evidence indicates PKG can regulate gene expression in the brain and several properties make it an attractive candidate for inducing long-term memories. ^ This dissertation reports that brief, noxious stimulation of a behaving, semi-intact preparation from mollusc, Aplysia californica, produces transcription-dependent, long-term hyperexcitability (LTH) of nociceptive sensory neurons that requires a nitric oxide (NO)-cGMP-protein kinase G (PKG) pathway and which lasts for at least 24 hours. Intracellular injection of cGMP is sufficient to induce LTH. Similarly, body wall injury induces LTH which can be blocked with specific inhibitors of the NO-cGMP-PKG pathway such as L-NMMA, ODQ, Rp-8-cGMPS, PKI-G and KT5823 by isolated perfusion of pleural ganglion sensory cells in or directly by intracellular injection. In contrast, specific inhibitors of the cAMP-PKA pathway (Rp-8-cAMPS, PKI-A and H-89) failed to block injury-induced LTH. Interestingly, co-injection of the cAMP-responsive element (CRE) blocked the induction of both cAMP and injury-induced LTH, but not cGMP-induced LTH. Furthermore, co-injection of cAMP and cGMP with the Ca2+ buffer BAPTA in reduced Ca2+ seawater blocked cAMP-, but not cGMP-induced LTH. These findings demonstrate that the NO-cGMP-PKG pathway and at least one other pathway (perhaps mediated by Ca2+), but not the cAMP-PKA pathway, are critical for inducing LTH during transient, noxious stimulation.^
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Exogenous ligands that bind to the estrogen receptor (ER) exhibit unique pharmacologies distinct from that observed with the endogenous hormone, 17β-estradiol (ED. Differential activity among ER ligands has been observed at the level of receptor binding, promoter interaction and transcriptional activation. Furthermore, xenoestrogens can display tissue-specific agonist activity on the cellular level, functioning as an agonist in one tissue and as an antagonist in another. That the same ligand, functioning through the same receptor, can produce differing agonist responses on the cellular level indicates that there are tissue-specific determinants of agonist activity. In these studies critical molecular determinants of agonist activity were characterized for several cell types. In the normal and neoplastic myometrium a proliferative response was dependent upon activation of AF2 of the ER, functioning as a determinant of agonism in this cell type. Progesterone receptor (PR) ligands transdominantly suppressed ER-mediated transcription and proliferation in uterine leiomyoma cells, indicating that ER/PR cross-talk can modulate agonist activity in a myometrial cell background. In the breast, the agonist response to ER ligands was investigated by employing a functional genomics approach to generate gene expression profiles. Treatment of breast cancer cells with the selective estrogen receptor modulator tamoxifen largely recapitulated the expression profile induced by treatment with the agonist E2, despite the well-characterized antiproliferative effects produced by tamoxifen in this cell type. While the expression of many genes involved in regulating cell cycle progression, including fos, myc, cdc25a, stk15 and cyclin A, were induced by both E2 and tamoxifen in breast cells, treatment with the agonist E2 specifically induced the expression of cyclin D1, fra-1 , and uracil DNA glycosylase. These results suggest that the inability of tamoxifen to transactivate expression of only a few key genes, functioning as cellular gatekeepers, prevent tamoxifen-treated breast cells from entering the cell cycle. Thus, the expression of these agonist-specific marker genes is a potential determinant of agonist activity at the cellular level in the breast. Collectively, studies in the breast and uterine myometrium have identified several mechanisms whereby ER ligands modulate ER-mediated signaling and provide insights into the biology of tissue-specific agonist activity in hormone-responsive tissues. ^
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A shortage of medical personnel has become a critical problem for developing countries attempting to expand the provision of medical services for the poor. In order to highlight the driving forces determining the international allocation of medical personnel, the cases of four countries, namely the Philippines and South Africa as source countries and Saudi Arabia and the United Kingdom as destination countries, are examined. The paper concludes that changes in demand generated in major destination countries determine the international allocation of medical personnel at least in the short run. Major destination countries often alter their policies on how many medical staff they can accept, and from where, while source countries are required to make appropriate responses to the changes in demand.
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This article explores Islamic politics in two Muslim-majority countries in Southeast Asia, Indonesia and Malaysia, by linking their trajectories, from late colonial emergence to recent upsurge, to broad concerns of political economy, including changing social bases, capitalist transformation, state policies, and economic crises. The Indonesian and Malaysian trajectories of Islamic politics are tracked in a comparative exercise that goes beyond the case studies to suggest that much of contemporary Islamic politics cannot be explained by reference to Islam alone, but to how Islamic identities and agendas are forged in contexts of modern and profane social contestation.