310 research outputs found

    Crucial cross-talk of interleukin-1β and progesterone in human choriocarcinoma

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    Copyright @ 2012 Spandidos Publications Ltd. This article can be accessed from the links below.This article has been made available through the Brunel Open Access Publishing Fund.Choriocarcinoma is a highly malignant epithelial tumour that is most often associated with hydatidiform mole and presents the most common emergency medical problem in the management of trophoblast disease. We hypothesise that the hormones/cytokines present within the tumour microenvironment play key roles in the development of choriocarcinoma. In this study we assessed the effects of interleukin-1β (IL-1β) on cell death in the presence or absence of the sex hormone progesterone using two choriocarcinoma cell lines (BeWo and JEG-3) as in vitro experimental models. Although IL-1β induced cell death in both cell lines, the effect was more pronounced in JEG-3 cells, where cell death reached 40% compared to 15% in BeWo cells. Cell death of JEG-3 cells in response to IL-1β was significantly decreased by co-treatment with 100 nM and 1000 nM progesterone and completely abolished at a progesterone concentration of 1000 nM. Progesterone was also able to induce phosphorylation of ERK1/2 in these cells. Pretreatment of JEG-3 cells with a specific MAPK inhibitor (UO126) inhibited progesterone's inhibitory effect on cell death. Collectively, these data provide evidence of cross-talk between progesterone and IL-1β in this aggressive and poorly understood tumour that involves activation of a MAPK pathway and involvement of numerous progesterone receptors.This research was funded by a National Institutes of Health Grant ESO12961. This article is made available through the Brunel Open Access Publishing Fund

    Overwinter fasting and re-feeding in rainbow trout: plasma growth hormone and cortisol levels in relation to energy mobilization

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    This study investigated the roles of cortisol and growth hormone during a period of fasting in overwintering salmonid fish. Indices of carbohydrate (plasma glucose, liver glycogen), lipid (plasma free fatty acids) and protein metabolism (plasma protein, total plasma amino acids) were determined, together with plasma growth hormone (GH), cortisol and somatolactin levels (SL) at intervals in three groups of rainbow trout (continuously fed; fasted for 9 weeks then fed; fasted for 17 weeks). In fasted fish, a decline in body weight and condition factor was accompanied by reduced plasma glucose and hepatic glycogen and increased plasma FFA. No consistent elevation of plasma GH occurred until after 8 weeks of fasting when plasma GH levels increased nine-fold. No changes were observed in plasma total protein and AA until between weeks 13 and 17 when both were reduced significantly. When previously fasted fish resumed feeding, plasma glucose and FFA, and hepatic glycogen levels rapidly returned to control values and weight gain resumed. No significant changes in plasma cortisol levels, related to feeding regime, were evident at any point during the study and there was no evidence that SL played an active role in the response to fasting. The results suggest that overwinter fasting may not represent a significant nutritional stressor to rainbow trout and that energy mobilisation during fasting may be achieved without the involvement of GH, cortisol or SL

    Examining the suitability of molecular and metabolomic-based techniques as tools for assessing the effects of pharmaceuticals in the aquatic environment

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    Pharmaceuticals represent important and indispensable elements in modern society and their usage is considerable. Post consumption and body-elimination, pharmaceuticals are not completely removed in sewage treatment works (STWs) and as such, have been detected at low levels in STW effluents, surface waters, seawaters, ground waters and some drinking waters. Accordingly, pharmaceutical toxicity has been detected in several aquatic organisms. To date, environmental risk assessments (ERA) examine for toxicity using a series of chronic toxicity assays that examine for standard physiological responses in algae, Daphnia and fish and do not address pharmaceutical mode of action. Therefore, using the fathead minnow (Pimephales promelas) and the β-blocking pharmaceutical propranolol as the test-species and test-drug, respectively, the aim of this study was to establish an intelligent targeted 4-phased ERA using molecular, in vivo exposure, metabolomic and quantitative expression analytical techniques. The first phase established that the fathead minnow expressed the β3bi-adrenergic receptor (AR), which is a target receptor for propranolol in humans. The in vivo pair-breeding assay suggested that at 1mgL-1 and 10mgL-1, propranolol levels in fish blood plasma exceeded the human therapeutic concentration and caused 80% and 100% mortality, respectively. The most likely causes of mortality were liver failure and central nervous system toxicity. It was not possible to identify a robust biomarker of propranolol exposure using proton nuclear magnetic resonance (1H NMR) as there was considerable metabolic variation between male liver tissues within the same treatment groups. β3bi¬¬-AR expression was significantly lower at 1mgL-1 in the brain and liver, which was most likely the result of desensitisation in response to elevated levels of epinephrine and cortisol. β3bi¬¬-AR expression was significantly increased in the heart at the environmentally relevant concentration of 0.001mgL 1, however it was not possible to link β3bi¬¬-AR expression to a toxic response. Propranolol is unlikely to pose a threat to the aquatic environment as the concentrations measured in the environment are approximately 1000-fold lower than those that induced a toxic response. The proposed ERA represents a marked improvement over the existing ERA as it addresses pharmaceutical mode of action and both subtle and physiological toxicity responses, however it still requires further validation studies to address both metabolomic and gene expression variation.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Pharmaceuticals in the aquatic environment : β-blockers as a case study

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    The presence of many human pharmaceuticals in the aquatic environment is now a worldwide concern and yet little is known of the chronic effects that these bioactive substances may be having on aquatic organisms. This study used mammalian pharmacodynamics to predict the mode of action of the 13-blocker, propranolol, on fish, in order to identify chronic effects in fathead minnows. β-blockers target β1- and β2-adrenergic receptors in humans and hence these receptors were characterised in the fathead minnow. It was found that fish possess β1- and β2-ARs that are structurally very similar to their mammalian counterparts. Further, the distributions of these two β-ARs in various organs of the fathead minnow were similar to those in mammals. Pair-breeding assays were conducted, in which fathead minnows were exposed to various concentrations of propranolol. To discover whether β-ARs had been up or down regulated by propranolol, molecular analysis was conducted on different tissues of the exposed fish using real-time polymerase-chain reactions (RT-PCR). Exposure of fathead minnows to propranolol caused acute toxicity at 10 mg/L. Propranolol caused a statistically significant decrease in reproduction at 1.0 mg/L, dose-related decreases in male weight, condition index and fatpad weight, and a dose-related increase in female GSI. Molecular analysis of βl- and β2-AR expression levels revealed a dose-related decrease in β2-AR expression in fathead liver and heart. LOEC and NOEC values were 0.1 mg/L and 0.01 mg/L, respectively. Propranolol plasma concentrations in fish exposed to water concentrations of 0.1 and 1.0 mg/L were greater than the human therapeutic concentration and hence these data very strongly support the fish plasma model proposed by Huggett et al. (2001).EThOS - Electronic Theses Online ServiceEuropean Union (as part of the ERAPharm consortium)GBUnited Kingdo

    Progesterone receptors in the human placenta : expression, signalling characteristics and functional relevance

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    The human placenta is a transient life sustaining organ which is responsible for mediating all the physiological exchanges between the mother and the fetus. The steroid hormone progesterone, often referred to as the hormone of pregnancy, is critical for the establishment and for maintaining the pregnancy. During the gestation period the human placenta produces progesterone which via interacting with the progesterone receptors exerts its many effects. Specific intracellular progesterone receptors (PRs) have been reported to mediate the genomic signalling of progesterone whereas recently two novel receptor families which are phylogenetically distinct to the nuclear receptor superfamily have been characterised, and shown to mediate progesterone’s non genomic actions. These are the multiple membrane progestin receptors (mPRα, mPRβ, and mPRγ) and progesterone membrane receptor component 1 (PGMRC-1). The rapid progesterone actions mediated via these non-classical progesterone receptors have received attention with main focus on their reproductive functions. Our aim is to elucidate the expression of the receptors in the human placenta, further understand the signalling pathways via which progesterone mediates its effects and lastly examine the functional relevance of these receptors in this organ. Choriocarcinoma cell lines are used frequently as placental models for investigations of steroid hormone actions, but until now little is known about the expression of progesterone receptors (PRs) in these cell lines. Quantitative RT-PCR revealed that in fully syncytialized BeWo cells (treated with 50 µM forskolin for 72 h) there was a significant down-regulation of mPRα and up-regulation of mPRβ and of the PGRMC1 when compared with non-syncytialized BeWo cells. Expression of all the mPR and PGRMC1 mRNAs was significantly lower in JEG-3 cells compared to non-syncytialized BeWo cells. Expression of PR-B was unaltered between the two BeWo states but was significantly higher in JEG-3 cells. Immunofluorescence analysis revealed that mPR proteins are differentially expressed in these choriocarcinoma cell lines as well as in the human placenta. The functionality of mPRs was investigated in vitro, using BeWo and JEG-3 cells that were treated with Org OD-02 (a specific mPR agonist), progesterone (P4) and R5020 (a specific nuclear PR agonist) in the presence or absence of the pro-inflammatory cytokine inteleukin-1β (IL-1β) at a concentration of 10ng/μl. The effect was more exacerbated in JEG-3 cells, where IL-1β induced 40% cell death when compared to BeWo cells that reached a modest but significant 15% cell death. When JEG-3 cells were treated with IL-1β and progesterone, there was a significant decrease in cell death at concentrations of 100nM and 1000nM. When cells were treated with 1000nM progesterone, IL-1β’s effect was completely abolished. Progesterone was also able to induce phosphorylation of ERK1/2 in these cells. Pretreatment of JEG-3 cells with a specific MAPK inhibitor (UO126) inhibited substantially the progesterone’s proliferative effect. Moreover, using the specific mPR agonist Org OD 02-0, we have shown that that the progestin antagonism of apoptotic effects of IL-1β on BeWo cells is mediated through mPRs. Quantitative PCR in clinical samples revealed a 2.8 fold decrease of mPRβ in labouring comparing to non-labouring tissues and 4.6 fold higher levels of mPRγ in preterm mPRγ compared to term placentas. The ratio of mPRα to PR-B was increased in term compared to preterm samples, whereas it was decreased in labour compared to non-labour placentas. There was also a high correlation between mPRα and PGRMC1 expression irrespective of pathologies. This study addressed many fundamental questions regarding how progestins exert their effect at placental level. It is evident that there is a higher order of complexity and changes in the ratios of placental progesterone receptors rather than individual fluctuations might affect subsequent signalling events.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    On sixfold coupled vibrations of thin-walled composite box beams

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    This paper presents a general analytical model for free vibration of thin-walled composite beams with arbitrary laminate stacking sequences and studies the effects of shear deformation over the natural frequencies. This model is based on the first-order shear-deformable beam theory and accounts for all the structural coupling coming from the material anisotropy. The seven governing differential equations for coupled flexural–torsional–shearing vibration are derived from the Hamilton’s principle. The resulting coupling is referred to as sixfold coupled vibration. Numerical results are obtained to investigate the effects of fiber angle, span-to-height ratio, modulus ratio, and boundary conditions on the natural frequencies as well as corresponding mode shapes of thin-walled composite box beams

    The effect of online and in-person team-based learning (TBL) on undergraduate endocrinology teaching during COVID-19 pandemic

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    BACKGROUND: Team-based learning (TBL) combines active and collaborative learning, while incorporating aspects of the flipped classroom approach and problem-based learning. The COVID-19 pandemic presented certain challenges in the delivery of TBL in class. In this study, we investigated the impact of TBL on the academic performance of final year Biomedical Sciences' undergraduate students in the context of an "Endocrine Disorders" study block. We did so by comparing the classical in-person approach and online delivery due to the COVID-19 pandemic. METHODS: A non-compulsory TBL session was introduced to the curriculum of this block, which followed the traditional 2-h lecture delivery. Comparative analysis was performed for the exam and coursework performance of students who attended the TBL sessions (online and in-person) and those that did not. RESULTS: Both cohorts of students who attended either in-person (n = 66) or online TBL sessions (n = 109) performed significantly better in their exams (p < 0.05) and a related coursework (p < 0.001 and p < 0.05, respectively) when compared to those that did not attend. For both these cohorts the exam mark distribution was much narrower compared to those that did not attend the TBL sessions where the majority of fails and "no shows" were recorded. CONCLUSIONS: Online and in-person TBL, can successfully supplement traditional lecture-based teaching and enhance the learning/performance, for complex medical subjects/topics. Our findings demonstrate that it is possible to deliver these sessions online with demonstrable benefit for students suggesting that there is greater flexibility in the use of TBL in higher education
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