928 resultados para steroid


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Embryo implantation into the endometrium is a complex biological process involving the integration of steroid hormone signaling, endometrial tissue remodeling and maternal- fetal communications. A successful pregnancy is the outcome of the timely integration of these events during the early stages of implantation. The involvement of ovarian steroid hormones, estrogen (E) and progesterone (P), acting through their cognate receptors, is essential for uterine functions during pregnancy. The molecular mechanisms that control the process of implantation are undergoing active exploration. Through our recent efforts, we identified the transcription factor, CCAAT Enhancer Binding Protein Beta (C/EBPb) as a prominent target of estrogen and progesterone signaling in the uterus. The development of a C/EBPb-null mouse model, which is infertile, presented us with an opportunity to analyze the role of this molecule in uterine function. We discovered that C/EBPb functions in two distinct manners: (i) by acting as a mediator of E-induced proliferation of the uterine epithelium and (ii) by controlling uterine stromal cell differentiation, a process known as decidualization, during pregnancy. My studies have delineated important mechanisms by which E regulates C/EBPb expression to induce DNA replication and prevent apoptosis of uterine epithelial cells during E-induced epithelial growth. In subsequent studies, I analyzed the role of C/EBPb in decidualization and uncovered a unique mechanism by which C/EBPb regulates the synthesis of a unique laminin-containing extracellular matrix (ECM) that supports stromal cell differentiation and embryo invasion. In order to better define the role of laminin in implantation, we developed a laminin gamma 1-conditional knockout mouse model. This is currently an area of ongoing investigation. The information gained from our analysis of C/EBPb function in the uterus provides new insights into the mechanisms of steroid hormone action during early pregnancy. Ultimately, our findings may aid in the understanding of dysregulation of hormone-controlled pathways that underlie early pregnancy loss and infertility in women.

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Exogenous androgenic steroids applied to pregnant sheep programmes a PCOS-like phenotype in female offspring. Via ultrasound guidance we applied steroids directly to ovine fetuses at d62 and d82 of gestation, and examined fetal (day 90 gestation) and postnatal (11 months old) pancreatic structure and function. Of three classes of steroid agonists applied (androgen - Testosterone propionate (TP), estrogen - Diethystilbesterol (DES) and glucocorticoid - Dexamethasone (DEX)), only androgens (TP) caused altered pancreatic development. Beta cell numbers were significantly elevated in prenatally androgenised female fetuses (P=0.03) (to approximately the higher numbers found in male fetuses), whereas alpha cell counts were unaffected, precipitating decreased alpha:beta cell ratios in the developing fetal pancreas (P=0.001), sustained into adolescence (P=0.0004). In adolescence basal insulin secretion was significantly higher in female offspring from androgen-excess pregnancies (P=0.045), and an exaggerated, hyperinsulinaemic response to glucose challenge (P=0.0007) observed, whereas prenatal DES or DEX treatment had no effects upon insulin secretion. Postnatal insulin secretion correlated with beta cell numbers (P=0.03). We conclude that the pancreas is a primary locus of androgenic stimulation during development, giving rise to postnatal offspring whose pancreas secreted excess insulin due to excess beta cells in the presence of a normal number of alpha cells.

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Background: Non-steroid anti-inflammatory drugs (NSAIDs) are a widely used therapeutic group in the world, and particularly in the Portuguese population. Objective: To compare NSAID’s use by prescription and self-medication acquisition and to determine the pattern of indication of NSAIDs, their usage profile and possible implications for patients’ safety. Methods: A cross-sectional design was used where individuals presenting at a community pharmacy requesting NSAIDs during the study period (one month) were invited to answer a face-to-face interview where socio-demographic characteristics, the indication pattern and previous experience of side effects were assessed. A follow-up interview was performed one week later to assess the incidence of adverse effects. The study was ethically approved. Results: A sample of 130 NSAIDs users was recruited, comprising mostly women (n=87; 66.9%), actively employed (n=77; 59.2%) and presenting a mean age of 49.5 years old (SD=20.49). An equal proportion of individuals acquired NSAIDs by self-medication and with medical prescription (n=65; 50%). Over 4/5 of patients (n=57; 87.7%) acquiring NSAIDs without a prescription were self-medicated by their own initiative, and only 10.8% (n=7) had been advised by the pharmacist. The most commonly acquired active substances were ibuprofen and diclofenac. Self-medicated users more frequently resorted to topical NSAIDs following short term treatments. The major underlying condition motivating NSAIDs sought were musculoskeletal disorders (45.0%), regardless of the regimen. An important proportion of prevalent users of NSAIDs reported previous experience of adverse effects (11.3%). One week after initiating NSAID therapy, a small proportion of patients reported incidence of adverse effects. Conclusion: Self-medication with NSAIDs is sought for numerous medical conditions. Reported adverse effects (prevalent and incident) confirm the need for a more rational use of NSAIDs and ongoing pharmacovigilance.

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Objectives: To highlight the occurrence of Hashimoto’s encephalopathy – a steroid-responsive encephalopathy associated with elevated antithyroid antibodies. Material and methods: We describe a clinically and biochemically euthyroid patient with an encephalopathy presenting with headache, mild confusion and personality changes for 6 weeks and tonic–clonic seizures upon admission Results: There was no obvious infective or metabolic cause. The patient had a high titre of antithyroid antibodies and responded to steroid therapy. Conclusion: This uncommon disease needs to be considered in patients presenting with neurological symptoms that remain unexplained after routine standard investigations, even when the patient is euthyroid. Early diagnosis is important, as this is a treatable condition.

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Objectives: To illustrate that the protease inhibitor (PI) ritonavir, widely used as part of the treatment for HIV, might cause drug–drug interactions with inhaled corticosteroids. Material and methods: A case report is presented. Results: An HIV-positive patient presented with gradually changing body composition that was ascribed to lipodystrophy. Finally, iatrogenic Cushing's syndrome with secondary adrenal insufficiency was diagnosed due to a drug–drug interaction of ritonavir and fluticasone. Conclusion: Lipodystrophy might mimic Cushing's syndrome. The combination of ritonavir and inhaled fluticasone may lead to systemic steroid excess causing Cushing's syndrome and secondary adrenal insufficiency.

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Background and objectives: Significantly elevated serum ferritin levels are associated with both iron overload and some inflammatory conditions. Hepcidin is a protein that interferes with iron absorption in inflammatory states and acts as an acute-phase reactant. Materials and methods: Here we report the case a 33-year-old patient who presented with high fever, skin lesions and arthralgia lasting for 2 weeks. His ferritin level was 13,800 µg/l and his hepcidin level was 61 ng/dl. Results: The final diagnosis was adult onset Still's disease. The condition evolved satisfactorily with steroid treatment, but after several weeks the patient presented with an unexpected recurrence. Conclusions: Hepcidin is a good inflammatory marker that could be useful in the differential diagnosis of hyperferritinaemia.

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Rheumatoid arthritis (RA), a systemic inflammatory disease, may induce pulmonary manifestations. We describe a case of longstanding RA presenting with eosinophilic pneumonia (EP). Rare case reports of tissue eosinophilia involving isolated organs in the setting of RA exist in the literature. It has been shown that the production of proinflammatory cytokines activates different cell group and can simultaneously play a role in RA and induce eosinophils infiltration in target tissue. An appropriate lowest possible dosage of steroid therapy is essential, whereas EP may be a rare subset of pulmonary involvement in RA.

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Anti-signal recognition particle (SRP) myopathy is a rare idiopathic inflammatory myositis that usually affects middle-age women, and is characterized by rapidly progressive proximal and symmetrical muscle weakness, elevated creatine kinase levels, severe necrotizing immune-mediated myopathy, presence of anti-SRP autoantibodies and poor response to steroid therapy. We report a geriatric case of a previously independent patient, presenting with slow onset of proximal paraparesis, myalgia and severe gait impairment. The patient was treated with steroid and azathioprine, with laboratory and pain response but modest muscle strength improvement. The clinical presentation of this unusual patient was atypical, which hampered the correct diagnosis.

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A avaliação do aporte de matéria orgânica no ambiente aquático por atividades antrópicas pode ser realizada através da identificação e quantificação de marcadores moleculares. Diversos estudos apontam à aplicação dos marcadores moleculares com esta finalidade, no entanto, poucos avaliam a variação das concentrações desses compostos ao longo do tempo, registrada nas camadas sedimentares. O presente trabalho realiza um estudo a partir de três classes de marcadores moleculares presentes em perfis sedimentares da região do Complexo Estuarino de Paranaguá (CEP) no Paraná (PR), que nos últimos anos vêm sofrendo com o crescente desenvolvimento de atividades antrópicas. Como objetivo, tem-se identificar as principais fontes de matéria orgânica e estudar o histórico destes aportes em colunas sedimentares do CEP, relacionando as taxas de sedimentação com a deposição de origem natural e antrópica. A legislação vigente para o monitoramento ambiental, no que diz respeito à contaminação por esgoto fecal, sugere a avaliação por indicadores microbiológicos, porém, indicadores químicos como os esteróides fecais são uma alternativa bastante promissora, pois estes são persistentes, sendo menos sensíveis a variações ambientais. Outros dois marcadores moleculares de aportes antrópicos ao ambiente que foram determinados neste estudo são os alquilbenzenos lineares (LABs), presente em detergentes, que indicam aportes antrópicos oriundos de esgoto doméstico e a determinação de cafeína, tendo em vista que os esteróides fecais podem ser originários de fezes de animais de sangue quente, podendo indicar outras fontes. Para o presente trabalho foram coletados 12 testemunhos de até 1 m de profundidade em maio de 2006, totalizando 12 pontos de coleta e um montante de 121 amostras. As análises foram realizadas por cromatografia em fase gasosa com detecção por espectrometria de massas (CG-EM). Os esteróides encontrados em maior concentração foram o β- sitosterol (71,4 µg g-1), estigmasterol (8,7 µg g-1), colestanol (3,6 µg g-1) e o estigmastanol (2,8 µg g-1), todos oriundos de fonte natural, indicando que a maior contribuição para o CEP é por aporte biogênico. O coprostanol, que é um esterol fecal, foi encontrado entre as concentrações de 0,001 e 4,10 µg g-1, outros dois esteróides de origem fecal também foram detectados, coprostanona e epicoprostanol, onde as maiores concentrações foram 3,6 e 0,2 µg g-1, respectivamente, sendo encontrados em regiões próximas a centros urbanos, indicando origem antrópica. As maiores concentrações para o ∑LABs também foram encontradas em regiões próximas às cidades de Antonina e Paranaguá, sendo a maior encontrada no testemunho #3 Gererês (208 ng g-1). Para o último marcador molecular analisado, a cafeína, foi encontrada a maior concentração de 18,41 ng g-1, sendo este ponto localizado longe dos centros urbanos, porém este contaminante é bastante solúvel em água podendo ser transportado na coluna d’água e percorrer grandes distâncias. Através dos compostos analisados, pode-se perceber que a intervenção antropogênica foi mais marcante nos testemunhos coletados no eixo leste-oeste do CEP, ficando registrado nas camadas sedimentares.

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Dans les dernières années, les perturbateurs endocriniens ont été observés dans les rivières qui reçoivent des entrées importantes d’eaux usées. Parmi les perturbateurs endocriniens, les hormones stéroïdiennes naturelles et synthétiques sont des composés dont le potentiel d'imiter ou d'interférer avec les fonctions hormonales normales (développement, croissance et reproduction), est reconnu même au niveau ultra-traces (ng L-1). Bien que les hormones conjuguées soient moins actives que les hormones libres, elles peuvent être clivées et redevenir libres une fois exposées aux processus microbiens avant ou pendant le traitement des eaux usées. En raison de la nécessité d'identifier et de quantifier ces composés dans l'eau, une nouvelle méthode, entièrement automatisée, a été développée pour la détermination simultanée des deux formes de plusieurs hormones stéroïdiennes (conjuguées et libres) dans les matrices d'eau et dans l’urine des femmes. La méthode est basée sur l'extraction en phase solide couplée en ligne à la chromatographie liquide et la spectrométrie de masse en tandem (SPE-LC-MS/MS). Plusieurs paramètres ont été évalués dans le but d'optimiser l'efficacité de la méthode, tels que le type et le débit de la phase mobile, des différentes colonnes de SPE et de chromatographie, ainsi que différentes sources et modes d'ionisation des échantillons pour la MS. La méthode démontre une bonne linéarité (R2 > 0.993), ainsi qu'une précision avec un coefficient de variance inférieure à 10%. Les limites de quantification varient d’un minimum de 3 à 15 ng L-1 pour un volume d'injection entre 1 mL et 5 mL et le recouvrement des composés varie de 72 % à 117 %.

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Mushrooms have the ability to promote apoptosis in tumor cell lines, but the mechanism of action is not quite well understood. Inhibition of the interaction between Bcl-2 and pro-apoptotic proteins could be an important step that leads to apoptosis. Therefore, the discovery of compounds with the ability to inhibit Bcl-2 is an ongoing research topic in drug discovery. In this study, we started by analyzing Bcl-2 experimental structures that are currently available in Protein Data Bank database. After analysis of the more relevant Bcl-2 structures, 4 were finally selected. An analysis of the best docking methodology was then performed using a cross-docking and re-docking approach while testing 2 docking softwares: AutoDock 4 and AutoDock Vina. Autodock4 provided the best docking results and was selected to perform a virtual screening study applied to a dataset of 40 Low Molecular Weight (LMW) compounds present in mushrooms, using the selected Bcl-2 structures as target. Results suggest that steroid are the more promising family, among the analyzed compounds, and may have the ability to interact with Bcl-2 and this way promoting tumor apoptosis. The steroids that presented lowest estimated binding energy (ΔG) were: Ganodermanondiol, Cerevisterol, Ganoderic Acid X and Lucidenic Lactone; with estimated ΔG values between -8,45 and -8,23 Kcal/mol. A detailed analysis of the docked conformation of these 4 top ranked LMW compounds was also performed and illustrates a plausible interaction between the 4 top raked steroids and Bcl-2, thus substantiating the accuracy of the predicted docked poses. Therefore, tumoral apoptosis promoted by mushroom might be related to Bcl-2 inhibition mediated by steroid family of compounds.

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O herbicida Atrazina (ATR) é um agrotóxico utilizado há cerca de 50 anos, responsável pelo controle seletivo de plantas daninhas em cultivo de arroz, milho e cana-de-açúcar, principalmente. Estudos recentes apontam diversos efeitos desse herbicida em invertebrados e vertebrados, através da contaminação do solo, bem como da lixiviação para os ecossistemas aquáticos. Foi demonstrado que a ATR é um desregulador endócrino, além de causar efeitos como estresse oxidativo, imunotoxicidade e distúrbios no metabolismo energético. No presente estudo, a espécie nativa Poecilia vivipara foi utilizada como modelo experimental para identificar e analisar a expressão de genes atuantes na via esteroidogênica (StAR e Cyp19a1) e genes atuantes no sistema de defesa antioxidante enzimático (SOD-1 e CAT), frente a exposição à diferentes concentrações de ATR. Sequências parciais dos genes-alvo foram obtidas e comparadas com sequências disponíveis de espécies próximas. Foram analisadas a expressão órgãoespecífica para cada um dos genes isolados, bem como a expressão dos genes frente à exposição ao herbicida atrazina. Os animais foram expostos a ATR em concentrações de 2, 10 e 100 µg/L e a expressão dos genes em gônadas e fígado desses animais foram analisadas em 24 e 96 horas de exposição. As sequências obtidas dos genes StAR, Cyp19a1, SOD-1 e CAT apresentaram 821, 80, 954, 350 pares de bases respectivamente, com identidades que variam de 86 a 100% com espécies filogeneticamente próximas a P. vivipara. Os animais apresentaram uma maior expressão dos genes StAR e Cyp19a1 nas gônadas e no fígado, enquanto a menor expressão se mostrou em órgãos como intestino e baço. Já os genes SOD e CAT apresentaram uma maior expressão no fígado, e menor expressão no intestino. Em relação à expressão gênica frente à exposição à ATR, os resultados apontaram para uma indução dos genes StAR, SOD e CAT em 24 horas, nas gônadas e no fígado, enquanto 8 que a expressão do gene Cyp19a1 foi aumentada apenas após 96 horas de exposição. Foi demonstrado que o herbicida ATR, mesmo em baixas concentrações, é capaz de desregular a expressão de genes que codificam tanto para proteínas componentes da via de síntese de hormônios esteróides, quanto para enzimas atuantes na resposta antioxidante celular de P. vivipara. 

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The B cell CLL/lymphoma-2 (Bcl-2) family is functionally classified as either anti-apoptotic or pro-apoptotic, and the regulation of its interactions dictates survival or commitment to apoptosis. Bcl-2 family is also implicated in a wide range of diseases. In some types of cancers, including lymphomas and epithelial cancers, protein overexpression of anti-apoptotic Bcl-2 family, such as the Bcl-2 protein is indicative of cancer in an advanced stage, with a poor prognosis and resistant to chemotherapy [1]. Several reports indicate that mushrooms have the ability to promote apoptosis in tumour cell lines, but the mechanism of action is not fully understood. Inhibition of the interaction between Bcl-2 (anti-apoptotic protein) and proapoptotic proteins could be an important step in the mechanism of mushroom induced apoptosis. Therefore, the discovery of compounds with the capacity to inhibit Bcl-2 is an ongoing research topic on cancer therapy. In this work, docking studies were performed using a dataset of 40 low molecular weight (LMW) compounds present in mushrooms. The docking software AutoDock 4 was used and docking studies were performed using 5 selected Bcl-2 crystal structures as targets. Compounds with the lowest predicted binding energy (predΔG) are expected to be the more potent inhibitors. Among the tested compounds, steroids presented the lowest predΔG with several exhibiting values below -9 kcal/mol. The results are corroborated by several reports that state that steroids induce apoptosis in several tumor cells. It is thus feasible that they might act by preventing Bcl-2 from forming complexes with the respective proapoptotic protein interaction partners, namely Bak, Bax, and Bim. Moreover, previous studies on our research group demonstrated that 48 h treatment of MCF-7 cells (breast carcinoma) with Suillus collinitus methanolic extract caused a decrease in Bcl-2, highlighting the antitumor potential of this mushroom species [2]. In conclusion, the process of apoptosis promoted by mushroom extracts may be related to the inhibition of Bcl-2 by the steroid derivatives herein studied. However, further studies are needed to confirm this hypothesis.

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Ovarian sex cord-stromal tumors are infrequent and represent approximately 7% of all primary ovarian tumors. This histopathologic ovarian tumor group differs considerably from the more prevalent epithelial ovarian tumors. Although sex cord-stromal tumors present in a broad age group, the majority tend to present as a low-grade disease that usually follows a nonaggressive clinical course in younger patients. Furthermore, because the constituent cells of these tumors are engaged in ovarian steroid hormone production (e.g., androgens, estrogens, and corticoids), sex cord-stromal tumors are commonly associated with various hormone-mediated syndromes and exhibit a wide spectrum of clinical features ranging from hyperandrogenic virilizing states to hyperestrogenic manifestations. The World Health Organization sex cord-stromal tumor classification has recently been revised, and currently these tumors have been regrouped into the following clinicopathologic entities: pure stromal tumors, pure sex cord tumors, and mixed sex cord-stromal tumors. Moreover, some entities considered in the former classification (e.g., stromal luteoma, stromal tumor with minor sex cord elements, and gynandroblastoma) are no longer considered separate tumors in the current classification. Herein, we discuss and revise the ultrasonography, computed tomography, and magnetic resonance imaging characteristics of the different histopathologic types and clinicopathologic features of sex cord-stromal tumors to allow radiologists to narrow the differential diagnosis when facing ovarian tumors.

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Statistical methodology is proposed for comparing molecular shapes. In order to account for the continuous nature of molecules, classical shape analysis methods are combined with techniques used for predicting random fields in spatial statistics. Applying a modification of Procrustes analysis, Bayesian inference is carried out using Markov chain Monte Carlo methods for the pairwise alignment of the resulting molecular fields. Superimposing entire fields rather than the configuration matrices of nuclear positions thereby solves the problem that there is usually no clear one--to--one correspondence between the atoms of the two molecules under consideration. Using a similar concept, we also propose an adaptation of the generalised Procrustes analysis algorithm for the simultaneous alignment of multiple molecular fields. The methodology is applied to a dataset of 31 steroid molecules.