Annals of the New York Academy of Sciences
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Ann. N. Y. Acad. Sci. · Jun 2004
ReviewSeasonal plasticity in the song control system: multiple brain sites of steroid hormone action and the importance of variation in song behavior.
Birdsong, in non-tropical species, is generally more common in spring and summer when males sing to attract mates and/or defend territories. Changes in the volumes of song control nuclei, such as HVC and the robust nucleus of the arcopallium (RA), are observed seasonally. Long photoperiods in spring stimulate the recrudescence of the testes and the release of testosterone. ⋯ Testosterone can act via brain-derived neurotrophic factor (BDNF) that is also released in HVC as a result of song activity. Testosterone could enhance song nucleus volume indirectly by acting in the preoptic area, a region regulating sexual behaviors, including song, that connects to the song system through catecholaminergic cells. Seasonal neuroplasticity in the song system involves an interplay among seasonal state, testosterone action, and behavioral activity.
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Ann. N. Y. Acad. Sci. · Jun 2004
ReviewThe origin and functions of multiple human glucocorticoid receptor isoforms.
Glucocorticoid hormones are necessary for life and are essential in all aspects of human health and disease. The actions of glucocorticoids are mediated by the glucocorticoid receptor (GR), which binds glucocorticoid hormones and regulates gene expression, cell signaling, and homeostasis. Decades of research have focused on the mechanisms of action of one isoform of GR, GRa. ⋯ We summarize here the processes that generate and modify various hGR isoforms with a focus on those that impact the ability of hGR to regulate target genes. We speculate that unique receptor compositions and relative receptor proportions within a cell determine the specific response to glucocorticoids. Unchecked expression of some isoforms, for example hGRbeta, has been implicated in various diseases.
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Ann. N. Y. Acad. Sci. · Jun 2004
ReviewFamilial/sporadic glucocorticoid resistance: clinical phenotype and molecular mechanisms.
Glucocorticoids regulate a variety of biologic processes and exert profound influences on many physiologic functions. Their actions are mediated by the glucocorticoid receptor (GR), which belongs to the nuclear receptor family of ligand-dependent transcription factors. Alterations in tissue sensitivity to glucocorticoids may manifest as states of resistance or hypersensitivity. ⋯ Compensatory elevations in circulating adrenocorticotropic hormone (ACTH) concentrations lead to increased production of adrenal steroids with mineralocorticoid and/or androgenic activity and their corresponding clinical manifestations, as well as increased urinary free-cortisol excretion in the absence of symptomatology suggestive of hypercortisolism. The molecular basis of the condition has been ascribed to mutations in the GR gene, which impair normal glucocorticoid signal transduction, altering tissue sensitivity to glucocorticoids. The present review focuses on the mechanisms of GR action and the clinical manifestations and molecular mechanisms of familial/sporadic glucocorticoid resistance.
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Ann. N. Y. Acad. Sci. · Jun 2004
Comparative StudyCell-free plasma DNA as a prognostic marker in intensive treatment unit patients.
Recent evidence suggests that cell-free plasma DNA has potential use as a prognostic marker in many clinical settings. The aim of the present study was to evaluate the prognostic role of cell-free plasma DNA in the prediction of clinical outcome in intensive treatment unit (ITU) patients. Cell-free plasma DNA was measured by real-time polymerase chain reaction assay for the beta-globin gene and SOFA score, APACHE II score, CRP concentrations, and clinical outcome (duration of stay, ventilation time, and mortality) were noted in 94 patients on admission to the ITU. ⋯ The median DNA concentration in nonsurvivors was 9148 GE/mL, and this was 2.3-fold greater than that in survivors (3921 GE/ml, P <0.001). ROC analysis of the data indicated a sensitivity of 85% and a specificity of 80% when DNA concentration of 6109 GE/mL was taken as a predictor of death. The data suggest that cell-free plasma DNA concentration is potentially useful as a prognostic marker in ITU patients.