467 research outputs found

    Social Media and Financial Market (<Special Issue>Theory and Application of Econometrics)

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    textabstractAll members of the steroid hormone receptor family are phosphoproteins. Additional phosphorylation occurs in the presence of hormone. This hormone-induced phosphorylation, which is 2- to 7-fold more than the basal phosphorylation, is a rapid process. All steroid receptors are phosphorylated at more than one single site. Most phosphorylation sites are located in the N-terminal domain, and phosphorylation occurs mainly on serine residues. Phosphorylation on threonine residues occurs in only a few cases. Phosphorylation on tyrosine residues has been found only for the estrogen receptor. Six different protein kinases are possibly involved in steroid receptor phosphorylation (estrogen receptor kinase; protein kinase A; protein kinase C; casein kinase II; DNA-dependent kinase; Ser-Pro kinases). Steroid receptor phosphorylation has been directly implicated in: activation of hormone binding, nuclear import of steroid receptors, modulation of binding to hormone response elements, and consequently in transcription activation

    Feasibility of a Unitary Quantum Dynamics in the Gowdy T3T^3 Cosmological Model

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    It has been pointed out that it is impossible to obtain a unitary implementation of the dynamics for the polarized Gowdy T3T^{3} cosmologies in an otherwise satisfactory, nonperturbative canonical quantization proposed for these spacetimes. By introducing suitable techniques to deal with deparametrized models in cosmology that possess an explicit time dependence (as it is the case for the toroidal Gowdy model), we present in this paper a detailed analysis about the roots of this failure of unitarity. We investigate the impediments to a unitary implementation of the evolution by considering modifications to the dynamics. These modifications may be regarded as perturbations. We show in a precise manner why and where unitary implementability fails in our system, and prove that the obstructions are extremely sensitive to modifications in the Hamiltonian that dictates the time evolution of the symmetry-reduced model. We are able to characterize to a certain extent how far the model is from unitarity. Moreover, we demonstrate that the dynamics can actually be approximated as much as one wants by means of unitary transformations.Comment: 12 pages, version accepted for publication in Physical Review

    Cellular uptake of steroids

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    The general concept concerning mechanism of steroid hormone action includes several steps at the molecular level about which very little is known. ·For several steroid responsive tissues it has been shown, that the steroid molecule after entering its target cell, becomes immediately bound by a "cytoplasmic receptor" which transfers the steroid into the nucleus. This translocation step is temperature dependent. Simultaneously the receptor part of the complex is transformed into a smaller subunit, the "nuclear receptor". In the nucleus the steroid receptor complex becomes attached to an acidic non histone protein, the "nuclear acceptor" site, and provokes an increase in RNA polymerase activity resulting in new RNA synthesis followed by increased protein synthesis

    Delay of phagosome maturation by a mycobacterial lipid is reversed by nitric oxide.

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    Mycobacterium tuberculosis is a facultative intracellular pathogen that inhibits phagosome maturation in macrophages thereby securing survival and growth. Mycobacteria reside in an early endocytic compartment of near-neutral pH where they upregulate production of complex glycolipids such as trehalose dimycolate. Here, we report that trehalose dimycolate coated onto beads increased the bead retention in early phagosomes, i.e. at a similar stage as viable mycobacteria. Thus, a single mycobacterial lipid sufficed to divert phagosome maturation and likely contributes to mycobacterial survival in macrophages. Previous studies showed that activated macrophages promote maturation of mycobacterial phagosomes and eliminate mycobacteria through bactericidal effectors including nitric oxide generated by inducible nitric-oxide synthase. We show that deceleration of bead phagosome maturation by trehalose dimycolate was abolished in immune-activated wild type, but not in activated nitric-oxide synthase-deficient macrophages, nor when hydroxyl groups of trehalose dimycolate were chemically modified by reactive nitrogen intermediates. Thus, specific host defence effectors of activated macrophages directly target a specific virulence function of mycobacteria

    On the rapid TeV flaring activity of Markarian 501

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    Aims: We investigate the one-zone SSC model of TeV blazars in the presence of electron acceleration. In this picture electrons reach a maximum energy where acceleration saturates from a combination of synchrotron and inverse Compton scattering losses. Methods: We solve the spatially averaged kinetic equations which describe the simultaneous evolution of particles and photons, obtaining the multi-wavelength spectrum as a function of time. Results: We apply the model to the rapid flare of Mrk 501 of July 9, 2005 as this was observed by the MAGIC telescope and obtain the relevant parameters for the pre-flare quasi steady state and the ones during the flare. We show that a hard lag flare can be obtained with parameters which lie well within the range already accepted for this source. Especially the choice of a high value of the Doppler factor seems to be necessary.Comment: 4 pages, 4 figures, to appear in A&A (Letters

    Proteomic analysis of androgen-regulated protein expression in a mouse fetal vas deferens cell line

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    During sex differentiation, androgens are essential for development of the male genital tract. The Wolffian duct is an androgen-sensitive target tissue that develops into the epididymis, vas deferens, and seminal vesicle. The present study aimed to identify androgen-regulated proteins that are involved in development of Wolffian duct-derived structures. We have used male mouse embryos transgenic for temperature-sensitive simian virus 40 large tumor antigen at 18 d of gestation, to generate immortalized mouse fetal vas deferens (MFVD) parental and clonal cell lines. The MFVD parental and clonal cell lines express androgen receptor protein and show features of Wolffian duct mesenchymal cells. Clonal cell line MFVD A6 was selected for proteomic analysis and cultured in the absence or presence of androgens. Subsequently, two-dimensional gel electrophoresis was performed on total cell lysates. Differentially expressed proteins were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and two androgen-regulated proteins were identified as mElfin and CArG-binding factor-A (CBF-A). CBF-A and mElfin are known to bind to cytoskeletal F-actin. Both proteins appeared to be regulated by androgens at the posttranslational level, possibly involving phosphorylation. Posttranslational modification of mElfin and CBF-A by androgens may be associated with a cytoskeletal change that is involved in androgen-regulated gene expression

    Androgen receptor expression in human ovarian and uterine tissue of long term androgen-treated transsexual women

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    Androgen receptor (AR) modulation in human uteri and ovaries of long term androgen-treated transsexual female patients was investigated. Androgen receptor expression was evaluated immunohistochemically in the ovaries of 11 and the endometria and myometria of six androgen-treated transsexual female patients. This was compared with AR expression in the ovaries and uteri of premenopausal and postmenopausal women not receiving treatment and in 10 ovaries of female patients with polycystic ovarian disease (PCOD). In the normal ovaries germinal epithelium, granulosa cells of antral follicles, corpus luteum, and thecal and stromal cells exhibited moderate AR expression. The more intense and uniform staining of ovarian stroma of female transsexual patients and those of patients with PCOD compared with ovarian stroma of normal controls was most remarkable. This similarity in histology and distribution of ARs supports the hypothesis that PCOD is an androgen-mediated disorder. Immunostaining for ARs was only occasionally detectable in the uteri of premenopausal and postmenopausal women. In contrast, myometrial and endometrial stroma of the uteri of female transsexual patients displayed an intense and diffuse nuclear immunostaining, but glandular epithelia remained unstained. Western blot analysis of the ovaries and uterine myometrial tissue samples from transsexual female patients confirmed the presence of the 110-kd AR molecule. Because the androgen treatment of some transsexual female patients was discontinued 6 weeks before they underwent hysterosalpingo-oophorectomy, our data indicate a stable and persistent androgen-induced up-regulation of AR expression in ovaries
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