16 research outputs found

    Polyamide-Scorpion Cyclam Lexitropsins Selectively Bind AT-Rich DNA Independently of the Nature of the Coordinated Metal

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    Cyclam was attached to 1-, 2- and 3-pyrrole lexitropsins for the first time through a synthetically facile copper-catalyzed “click” reaction. The corresponding copper and zinc complexes were synthesized and characterized. The ligand and its complexes bound AT-rich DNA selectively over GC-rich DNA, and the thermodynamic profile of the binding was evaluated by isothermal titration calorimetry. The metal, encapsulated in a scorpion azamacrocyclic complex, did not affect the binding, which was dominated by the organic tail

    Characterization of an Nmr Homolog That Modulates GATA Factor-Mediated Nitrogen Metabolite Repression in Cryptococcus neoformans

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    Nitrogen source utilization plays a critical role in fungal development, secondary metabolite production and pathogenesis. In both the Ascomycota and Basidiomycota, GATA transcription factors globally activate the expression of catabolic enzyme-encoding genes required to degrade complex nitrogenous compounds. However, in the presence of preferred nitrogen sources such as ammonium, GATA factor activity is inhibited in some species through interaction with co-repressor Nmr proteins. This regulatory phenomenon, nitrogen metabolite repression, enables preferential utilization of readily assimilated nitrogen sources. In the basidiomycete pathogen Cryptococcus neoformans, the GATA factor Gat1/Are1 has been co-opted into regulating multiple key virulence traits in addition to nitrogen catabolism. Here, we further characterize Gat1/Are1 function and investigate the regulatory role of the predicted Nmr homolog Tar1. While GAT1/ARE1 expression is induced during nitrogen limitation, TAR1 transcription is unaffected by nitrogen availability. Deletion of TAR1 leads to inappropriate derepression of non-preferred nitrogen catabolic pathways in the simultaneous presence of favoured sources. In addition to exhibiting its evolutionary conserved role of inhibiting GATA factor activity under repressing conditions, Tar1 also positively regulates GAT1/ARE1 transcription under non-repressing conditions. The molecular mechanism by which Tar1 modulates nitrogen metabolite repression, however, remains open to speculation. Interaction between Tar1 and Gat1/Are1 was undetectable in a yeast two-hybrid assay, consistent with Tar1 and Gat1/Are1 each lacking the conserved C-terminus regions present in ascomycete Nmr proteins and GATA factors that are known to interact with each other. Importantly, both Tar1 and Gat1/Are1 are suppressors of C. neoformans virulence, reiterating and highlighting the paradigm of nitrogen regulation of pathogenesis

    Understanding the Warburg effect and the prognostic value of stromal caveolin-1 as a marker of a lethal tumor microenvironment

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    Cancer cells show a broad spectrum of bioenergetic states, with some cells using aerobic glycolysis while others rely on oxidative phosphorylation as their main source of energy. In addition, there is mounting evidence that metabolic coupling occurs in aggressive tumors, between epithelial cancer cells and the stromal compartment, and between well-oxygenated and hypoxic compartments. We recently showed that oxidative stress in the tumor stroma, due to aerobic glycolysis and mitochondrial dysfunction, is important for cancer cell mutagenesis and tumor progression. More specifically , increased autophagy/mitophagy in the tumor stroma drives a form of parasitic epithelial-stromal metabolic coupling. These findings explain why it is effective to treat tumors with either inducers or inhibitors of autophagy, as both would disrupt this energetic coupling. We also discuss evidence that glutamine addiction in cancer cells produces ammonia via oxidative mitochondrial metabolism. Ammonia production in cancer cells, in turn, could then help maintain autophagy in the tumor stromal compartment. In this vicious cycle, the initial glutamine provided to cancer cells would be produced by autophagy in the tumor stroma. Thus, we believe that parasitic epithelial-stromal metabolic coupling has important implications for cancer diagnosis and therapy, for example, in designing novel metabolic imaging techniques and establishing new targeted therapies. In direct support of this notion, we identified a loss of stromal caveolin-1 as a marker of oxidative stress, hypoxia, and autophagy in the tumor microenvironment, explaining its powerful predictive value. Loss of stromal caveolin-1 in breast cancers is associated with early tumor recurrence, metastasis, and drug resistance, leading to poor clinical outcome

    Manifestações extra-esofágicas da doença do refluxo gastroesofágico Extraesophageal manifestations of gastroesophageal reflux disease

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    A doença do refluxo gastroesofágico freqüentemente se apresenta com pirose e regurgitação, os chamados sintomas típicos. Porém, um subgrupo de pacientes apresenta um conjunto de sinais e sintomas que não estão relacionados diretamente ao dano esofágico. A esse conjunto dá-se o nome de manifestações extra-esofágicas da doença do refluxo gastroesofágico. Compreendem, principalmente, broncoespasmo, tosse crônica e alterações inflamatórias na laringe (chamados manifestações atípicas). Apesar de essas manifestações formarem um grupo heterogêneo, algumas considerações gerais englobam todos os subgrupos: embora a associação entre a doença do refluxo gastroesofágico e as manifestações extra-esofágicas esteja bem estabelecida, uma relação entre causa e efeito definitiva ainda não está elucidada; em relação à patogênese das manifestações extra-esofágicas, os principais mecanismos propostos são a injúria direta do tecido extra-esofágico pelo conteúdo ácido gástrico refluído e o reflexo esôfago-brônquico mediado pelo nervo vago; a doença do refluxo gastroesofágico pode não ser incluída no diagnóstico diferencial do grupo de pacientes que apresenta somente os sintomas atípicos. Este artigo revisa as manifestações extra-esofágicas da doença do refluxo gastroesofágico encontradas na literatura, discutindo a epidemiologia, patogênese, diagnóstico e tratamento, com foco nas apresentações mais estudadas e estabelecidas.<br>Gastroesophageal reflux disease often presents as heartburn and acid reflux, the so-called "typical" symptoms. However, a subgroup of patients presents a collection of signs and symptoms that are not directly related to esophageal damage. These are known collectively as the extraesophageal manifestations of gastroesophageal reflux disease. Principal among such manifestations are bronchospasm, chronic cough and laryngitis, which are classified as atypical symptoms. These manifestations comprise a heterogeneous group. However, some generalizations can be made regarding all of the subgroups. First, although the correlation between gastroesophageal reflux disease and the extraesophageal manifestations has been well established, a cause-and-effect relationship has yet to be definitively elucidated. In addition, the main proposed pathogenic mechanisms of extraesophageal reflux are direct injury of the extraesophageal tissue (caused by contact with gastric acid) and the esophagobronchial reflex, which is mediated by the vagus nerve. Furthermore, gastroesophageal reflux disease might not be considered in the differential diagnosis of patients presenting only the atypical symptoms. In this article, we review the extraesophageal manifestations of gastroesophageal reflux disease, discussing its epidemiology, pathogenesis, diagnosis and treatment. We focus on the most extensively studied and well-established presentations

    Current trends in initial management of oropharyngeal cancer: the declining use of open surgery.

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    Item does not contain fulltextThe widespread availability of novel primary treatment approaches against oropharyngeal cancers has provided several potentially curative surgical and nonsurgical treatment options for patients, generating both hope and controversy. As treatment is usually curative in intent, management considerations must include consideration of primary tumor and nodal disease control as well as long-term toxicities and functional outcomes. Anatomical and functional organ preservation (speech and deglutition) remains of paramount importance to patients with oropharyngeal cancer and the physicians involved in their care, accounting for the growing popularity of chemoradiotherapy and transoral surgical techniques for this indication. These novel approaches have greatly diminished the role of open surgery as initial therapy for oropharyngeal cancers. Open surgery which is often reserved for salvage on relapse, may still be an appropriate therapy for certain early stage primary lesions. The growing treatment armamentarium requires careful consideration for optimal individualized care. The identification of oncogenic human papillomavirus as a predictive and prognostic marker in patients with oropharyngeal cancer has great potential to further optimize the choice of treatment. In this review, novel primary therapies against oropharyngeal squamous cell carcinoma are presented in the context of anatomical, quality of life, and emerging biological considerations

    The prevalence and determinants of antepartum mental health problems among women in the USA: a nationally representative population-based study

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    Mental health problems disproportionately affect women, particularly during childbearing years. We sought to estimate the prevalence of antepartum mental health problems and determine potential risk factors in a representative USA population. We examined data on 3,051 pregnant women from 11 panels of the 1996–2006 Medical Expenditure Panel Survey. Poor antepartum mental health was defined by self report of mental health conditions or symptoms or a mental health rating of “fair” or “poor.” Multivariate regression analyses modeled the odds of poor antepartum mental health; 7.8% of women reported poor antepartum mental health. A history of mental health problems increased the odds of poor antepartum mental health by a factor of 8.45 (95% CI, 6.01–11.88). Multivariate analyses were stratified by history of mental health problems. Significant factors among both groups included never being married and self-reported fair/poor health status. This study identifies key risk factors associated with antepartum mental health problems in a nationally representative sample of pregnant women. Women with low social support, in poor health, or with a history of poor mental health are at an increased risk of having antepartum mental health problems. Understanding these risk factors is critical to improve the long-term health of women and their children
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