1,720,977 research outputs found
Sex steroid hormones influence the cAMP content in human endometrium during the menstrual cycle.
No full textThe measurement of the tissue concentrations of cyclic adenosine monophosphate (cAMP) in human endometrium shows that the levels of the nucleotide vary during the menstrual cycle, being 11.4 +/- (SE) 2.5 and 37.7 +/- (SE) 10.1 pmol/mg protein in the proliferative and secretory phase, respectively. The individual determinations of cAMP are significantly correlated to the estradiol/progesterone blood concentration ratio: by this means we obtained a superimposable distribution with the results of histologic examination suggesting that the hormones have a direct action in determining the cAMP levels in this tissue. The relevance of these observations for the physiology of the endometrium is discussed
Studies on amniotic prolactin: Chromatographic pattern and correlation with the lecithin content
No full textWe have measured the concentrations of prolactin and lecithin in the amniotic fluid from 20 normal pregnant women in the 2nd and 3rd trimester. Prolactin is present totally as a low-molecular-weight form, 'little' prolactin, and appears to correlate negatively with lecithin during the 2nd and positively during the 3rd trimester. On the basis of these results and of the information that prolactin is present as high-molecular-weight isohormones in maternal blood, it is argued that amniotic prolactin is synthesized 'in situ' and that different mechanisms are involved in the regulation of prolactin production
Effect of the hormonal contraception on serum reverse triiodothyronine levels
No full textThyroid hormones and the thyroxine-binding globulin are increased during hormonal treatment with oral contraceptives without changes in the thyroidal economy. Now we report that even reverse triiodothyronine, the main peripheral catabolite of thyroxine, is significantly increased during therapy with oral contraceptives
TRANSGLUTAMINASE-CATALYZED POLYMERIZATION OF TROPONIN IN-VITRO
No full textIn the presence of calcium ions, tissue transglutaminase catalyzes the polymerization of skeletal muscle troponin to high molecular weight insoluble aggregate. The specific action of transglutaminase is proved by the isolation of glutamyl-spermidine isopeptide derivatives. The process involves mainly the troponin T subunit (TnT), with formation of dimers and trimers of TnT, which were reactive with specific antibodies by immunoblotting. Furthermore when incubation is carried out in the presence of radioactive polyamines, the label is incorporated selectively into TnT subunit
Inactivation and cleavage of liver 6-P-gluconate dehydrogenase during irradiation in the presence of vanadate
No full textLamb liver phosphogluconate dehydrogenase is inactivated and selectively cleaved during irradiation in the presence of vanadate. Under our experimental conditions, the correlation between the species of vanadate in solution and rates of enzyme inactivation and cleavage indicates tetravanadate as the most likely photosensitizing agent, in agreement with previous data on other proteins. The enzyme is inactivated more rapidly at acidic pH and is partially protected by the coenzyme NADP, but not by the substrate phosphogluconate. Complete inactivation is obtained when only half of the protein is cleaved into smaller peptides. Differences in the pattern of the peptides produced are observed when irradiation is carried out in phosphate rather than in Hepes buffer: in the former instance cleavage results into formation of a main peptide of 47 kDa, while in latter case two additional peptides of 31 and 25 kDa are produced
Hormonal sensitivity of adenylate cyclase from human endometrium: modulation by estradiol.
No full textIn human endometria, a membrane-bound adenylate cyclase is present, which is recovered in high yield in a low-speed particulate fraction. Neither the specific activity of the enzyme nor the response to modifiers that act through the regulatory subunit of the complex, are modified during the proliferative or secretory phase of the cycle. Surprisingly, we found that in vitro treatment of secretory endometrial membranes with 17 beta-estradiol stimulates 3- to 4-fold the activity of adenylate cyclase. However this response does not occur on proliferative membranes. The activation by estradiol is independent of the presence of guanylylimidodiphosphate and is additive to that of the nucleotide. Possibly, as the consequence of the phenomenon, the concentration of cyclic AMP is significantly higher in curretage samples obtained from patients during the secretory rather than in the proliferative phase of the cycle. To our knowledge this is the first evidence of a target-cell membrane-directed effect of sex steroids in humans
Metabolic fingerprinting of breast cancer cell lines: discovering similarities and differences
No full textMetabolic fingerprinting of breast cancer cell lines: discovering similarities and differences.
Metabolic rewiring is one of the hallmarks of cancer. The metabolic reprogramming process is complex and influenced by multiple factors. It depends on the type and specific features of tumours. This study aimed to create a database of the metabolomes of selected breast cancer (BrCa) cell lines derived from tumour subtypes with different aggressiveness and to identify shared and unique features to understand the metabolic reprogramming of BrCa better. We selected five cell lines commonly used for in vitro studies, including MCF-7 and T-47D (luminal A), SK-Br-3 (HER2+), and MDA-MB-436 and MDA-MB-231 (triple negative), and two patient-derived xenografts Hbcx9 and Hcbx39 (triple negative). We used 1H-NMR spectroscopy to obtain the intracellular polar metabolic profiles of these BrCa cells cultured in optimal growth conditions. The seven cell lines exhibit distinct metabolomes, reflecting the heterogeneity of BrCa tumours. Using enriched metabolites, we identified cell-specific activated metabolic pathways. Remarkably, for the four triple negative cells, different pathways are preferentially activated: inositol phosphate metabolism in Hbcx9, purine metabolism in Hbcx39, the Krebs cycle and pyrimidine metabolism in MDA-MB-231, and nicotinate and niacinamide metabolism in MDA-MB-436. Since all patients with triple-negative tumours usually receive standardised chemotherapy, this finding may provide a prospective insight towards developing more personalised therapies. In addition, despite the metabolic differences, some metabolites can be associated with the current tumour subtype classification and aggressiveness. Finally, we compared known metabolic adaptive features of cancer within the cell lines. This study provides a database of the intracellular metabolite profiles of selected BrCa cell lines that can be useful for future research studies. It also uncovered specific features that may be helpful in the discovery of new therapeutic targets
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
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