1,720,965 research outputs found
Autoinduction of estrogen receptor is associated with FOSP-1 mRNA induction by estrogen in primary cultures of Xenopus oviduct cells
No full textThyroid hormone and glucocorticoid independently regulate the expression of estrogen receptor in male Xenopus liver cells.
No full textEarlier studies from our laboratory had shown that triiodothyronine (T-3) strongly potentiates the activation by estradiol (E(2)) of silent vitellogenin (Vit) genes and the autoinduction of estrogen receptor (ER) mRNA in primary cultures of male Xenopus hepatocytes (Rabelo and Tata, 1993). It was, however, not known if T-3, or other hormones, could up-regulate ER mRNA in the absence of exogenous E(2). We now show that T-3 and dexamethasone (Dex), but not progesterone and testosterone, directly induce ER mRNA within 4 h by separate pathways, at doses compatible with the K-d values of their receptors. This induction of ER mRNA is accompanied by a marked enhancement of the activation of the silent Vit B1 gene if E(2) is added by 12 h after T-3 and Dex, thus suggesting an elevated level of functional ER induced by the two hormones. This conclusion was supported by a higher rate of transcription from an estrogen response element (ERE)-tk-CAT construct transfected into cultured hepatocytes pre-treated with T-3 and Dex before incubation with estrogen. Our findings emphasize the importance of hormonal interplay via auto- and cross-regulation of nuclear hormone receptors
Characterization of nascent and secreted thyroxine-binding globulin in cultured human hepatoma (Hep G2) cells
No full textRuolo dei recettori per l’ormone tiroideo e per l’acido 9 cis retinoico nel corso delle metamorfosi di anfibio
No full textExploration of human and Xenopous dominant negative thyroid hormone receptor (TR) mutants to characterize the role of wild-type TR in the regulation of gene expression during amphibian metamorphosis
No full textDominant-negative mutant thyroid hormone receptors prevent transcription from Xenopus thyroid hormone receptor beta gene promoter in response to thyroid hormone in Xenopus tadpoles in vivo
No full textWe describe a dominant-negative approach in vivo to assess the strong, early upregulation of thyroid hormone receptor beta (TR beta) gene in response to thyroid hormone, characteristic of the onset of natural and thyroid hormone-induced amphibian metamorphosis, 3,3',5-Triiodothyronine (T-3) treatment of organ cultures of premetamorphic Xenopus tadpole tails coinjected in vivo with the wild-type Xenopus TR beta (wt-xTR beta) and three different thyroid responsive element chloramphenicol acetyltransferase (TRE-CAT) reporter constructs, including a direct repeat +4 (DR +4) element in the -200/+87 fragment of the xTR beta promoter, resulted in a 4- to 8-fold enhancement of CAT activity, Two human C-terminal TR beta 1 mutants (Delta-hTR beta 1 and fs-hTR beta 1), an artificial Xenopus C-terminal deletion mutant (mt-xTR beta), and the oncogenic viral homolog v-erbA none of which binds T-3, inhibited this T-3 response of the endogenous wt-xTR in Xenopus XTC-2 cells cotransfected with the -1600/+87 xTR beta promoter-CAT construct, the potency of the dominant-negative effect of these mutant TRs being a function of the strength of their heterodimerization with Xenopus retinoid X receptor gamma, Coinjection of the dominant-negative Xenopus and human mutant TR beta s into Xenopus tadpole tails totally abolished the T-3 responsiveness of the wt-xTR beta with different TREs, including the natural DR +4 TRE of the xTR beta promoter
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Recettori tiroidei dominanti negativi bloccano la stimolazione della trascrizione genica in risposta agli ormoni tirodei in vivo
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