991 resultados para Anisosmotic extracellular regulation
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Explanatory Memorandum
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Draft Statutory Instruments
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Mast cells and eosinophils actively participate in tissue repair and are prominent components of Schistosoma mansoni granulomas. Since pentoxifillyne (PTX) is an immunomodulatory and antifibrotic substance, we aimed to characterize, by morphological techniques, the effect of this drug on fibrosis developed inside murine hepatic schistosomal granulomatous reaction, beyond the quantification of eosinophil and mast cell populations. The drug (1 mg/100 g animal weight) was administrated from 35 to 90 days post-infection, when the animals were killed. The intragranulomatous interstitial collagen network was analyzed by confocal laser scanning microscopy, the number of eosinophils and mast cells was quantified and the results were validated by t-student test. Treatment did not interfere on the granuloma evolution but caused a significant decrease in the total and involutive number of hepatic granulomas (p = 0.01 and 0.001, respectivelly), and in the intragranulomatous accumulation of eosinophils (p = 0.0001). Otherwise, the number of mast cells was not significantly altered (p = 0.9); however, it was positively correlated with the number of granulomatous structures (r = 0.955). In conclusion, PTX does not affect development and collagen deposition in S. mansoni murine granuloma, but decreases the intragranulomatous eosinophil accumulation possibly due to its immunomodulatory capability, interfering in cellular recruitment and/or differentiation.
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In Pseudomonas aeruginosa, the small RNA-binding, regulatory protein RsmA is a negative control element in the formation of several extracellular products (e.g., pyocyanin, hydrogen cyanide, PA-IL lectin) as well as in the production of N-acylhomoserine lactone quorum-sensing signal molecules. RsmA was found to control positively the ability to swarm and to produce extracellular rhamnolipids and lipase, i.e., functions contributing to niche colonization by P. aeruginosa. An rsmA null mutant was entirely devoid of swarming but produced detectable amounts of rhamnolipids, suggesting that factors in addition to rhamnolipids influence the swarming ability of P. aeruginosa. A small regulatory RNA, rsmZ, which antagonized the effects of RsmA, was identified in P. aeruginosa. Expression of the rsmZ gene was dependent on both the global regulator GacA and RsmA, increased with cell density, and was subject to negative autoregulation. Overexpression of rsmZ and a null mutation in rsmA resulted in quantitatively similar, negative or positive effects on target genes, in agreement with a model that postulates titration of RsmA protein by RsmZ RNA.
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This report has been written in the context of this interest and in response to a request from the Department of Health and Children. It follows a Forum on regulatory issues that was held at the IPA in June 2001 and attended by many CAM practitioners. The Minister for Health and Children asked the Institute to build on the discussions at the Forum by preparing a report on possible options in the regulation of CAM practitioners in Ireland. The focus of the report is on regulatory and policy issues in general. It is not within the Instituteâ?Ts competence or brief to comment on more specific clinical or technical issues. Download the document here
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The mechanical behaviour of ectodermal cells in the area opaca and the supracellular organization of fibronectin in the adjacent extracellular matrix were studied in whole chick blastoderms developing in vitro. The pattern of spontaneous mechanical activity and its modification by immunoglobulins against fibronectin were determined using a real-time image-analysis system. The pattern of fibronectin was studied using immunocytochemical techniques. It was found that the ectodermal cells in the area opaca actively develop a radially oriented contraction, which leads to a distension of the area pellucida from which the embryo develops. Abnormally increased tension resulted in perturbations of gastrulation and neurulation. An optimized mechanical equilibrium within the blastoderm seems to be necessary for normal development. Anti-fibronectin antibodies applied to the basal side of the blastoderm led rapidly and reversibly to an increase of tension in the contracted cells. This observation indicates that modifications of the extracellular matrix can be transmitted to cytoskeletal elements within adjacent cells. The extracellular matrix of the area opaca contains fibronectin arranged in radially oriented fibrils. This orientation corresponds to the direction of migration of the mesodermal cells. Interestingly, the radial pattern of fibronectin is found in the regions where the ectodermal cells are contracted and develop radially oriented forces. This observation suggests that the supracellular assembly of the extracellular materials could be influenced by the mechanical activity of adjacent cells. Possible modulations of the supracellular organization of extracellular matrix by other factors, e.g. diffusible metabolites, is also discussed. The presence of characteristically organized extracellular matrix components, of spatially differentiated cell activities and of reciprocal interactions between them makes the young chick blastoderm an excellent system for physiological studies of the coordinated cellular activities that lead to changes in form, complexity and function.
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The mechanisms through which aldosterone promotes apparently opposite effects like salt reabsorption and K(+) secretion remain poorly understood. The identification, localization, and physiological analysis of ion transport systems in distal nephron have revealed an intricate network of interactions between several players, revealing the complex mechanism behind the aldosterone paradox. We review the mechanisms involved in differential regulation of ion transport that allow the fine tuning of salt and K(+) balance.
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Intense inflammatory lesions and early development of interstitial fibrosis of the myocardium and skeletal muscle with spontaneous regression, have been described in Calomys callosus infected with Trypanosoma cruzi. The genetic types of collagen present in this model were investigated through immunohistochemistry using specific antibodies, combined with histopathology and Picro-Sirius staining of collagen. Thirty-five calomys were infected with the Colombian strain of T. cruzi and sacrificed at 24, 30, 40, 60 and 90 days post-infection. Inflammatory lesions and fibrogenesis were prominent at the early phase of infection and significantly decreased during late infection. Immunoisotyping of the matrix components was performed by indirect immunofluorescence on 5 µm thick cryostat sections using specific antibodies against laminin, fibronectin and isotypes I, III and IV of collagen. In the early phase, positive deposits of all the matrix components were present, with predominance of fibronectin, laminin and collagens types I and III in the myocardium and of types III and IV in the skeletal muscles. From the 40th day, type IV collagen predominates in the heart. At the late phase of infection (60th to 90th day), a clear fragmentation and decrease of all the matrix components were detected. Findings of the present study indicate that a modulation of the inflammatory process occurs in the model of C. callosus, leading to spontaneous regression of fibrosis independent of the genetic types of collagen involved in this process.
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OBJECTIVE: To investigate the involvement of the nuclear factor (NF)-kappaB in the interleukin (IL)-1 beta-mediated macrophage migration inhibitory factor (MIF) gene activation. DESIGN: Prospective study. SETTING: Human reproduction research laboratory. PATIENT(S): Nine women with endometriotic lesions. INTERVENTION(S): Endometriotic lesions were obtained during laparoscopic surgery. MAIN OUTCOME MEASURE(S): The MIF protein secretion was analyzed by ELISA, MIF mRNA expression by quantitative real-time polymerase chain reaction (PCR), NF-kappaB translocation into the nucleus by electrophoresis mobility shift assay, I kappaB phosphorylation and degradation by Western blot, and human MIF promoter activity by transient cell transfection. RESULT(S): This study showed a significant dose-dependent increase of MIF protein secretion and mRNA expression, the NF-kappaB translocation into the nucleus, I kappaB phosphorylation, I kappaB degradation, and human MIF promoter activity in endometriotic stromal cells in response to IL-1 beta. Curcumin (NF-kappaB inhibitor) significantly inhibited all these IL-1 beta-mediated effects. Analysis of the activity of deletion constructs of the human MIF promoter and a computer search localized two putative regulatory elements corresponding to NF-kappaB binding sites at positions -2538/-2528 bp and -1389/-1380 bp. CONCLUSION(S): This study suggests the involvement of the nuclear transcription factor NF-kappaB in MIF gene activation in ectopic endometrial cells in response to IL-1 beta and identifies a possible pathway of endometriosis-associated inflammation and ectopic cell growth.
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Résumé grand public :Le cerveau se compose de cellules nerveuses appelées neurones et de cellules gliales dont font partie les astrocytes. Les neurones communiquent entre eux par signaux électriques et en libérant des molécules de signalisation comme le glutamate. Les astrocytes ont eux pour charge de capter le glucose depuis le sang circulant dans les vaisseaux sanguins, de le transformer et de le transmettre aux neurones pour qu'ils puissent l'utiliser comme source d'énergie. L'astrocyte peut ensuite utiliser ce glucose de deux façons différentes pour produire de l'énergie : la première s'opère dans des structures appelées mitochondries qui sont capables de produire plus de trente molécules riches en énergie (ATP) à partir d'une seule molécule de glucose ; la seconde possibilité appelée glycolyse peut produire deux molécules d'ATP et un dérivé du glucose appelé lactate. Une théorie couramment débattue propose que lorsque les astrocytes capturent le glutamate libéré par les neurones, ils libèrent en réponse du lactate qui servirait de base énergétique aux neurones. Cependant, ce mécanisme n'envisage pas une augmentation de l'activité des mitochondries des astrocytes, ce qui serait pourtant bien plus efficace pour produire de l'énergie.En utilisant la microscopie par fluorescence, nous avons pu mesurer les changements de concentrations ioniques dans les mitochondries d'astrocytes soumis à une stimulation glutamatergique. Nous avons démontré que les mitochondries des astrocytes manifestent des augmentations spontanées et transitoires de leur concentrations ioniques, dont la fréquence était diminuée au cours d'une stimulation avec du glutamate. Nous avons ensuite montré que la capture de glutamate augmentait la concentration en sodium et acidifiait les mitochondries des astrocytes. En approfondissant ces mécanismes, plusieurs éléments ont suggéré que l'acidification induite diminuerait le potentiel de synthèse d'énergie d'origine mitochondriale et la consommation d'oxygène dans les astrocytes. En résumé, l'ensemble de ces travaux suggère que la signalisation neuronale impliquant le glutamate dicte aux astrocytes de sacrifier temporairement l'efficacité de leur métabolisme énergétique, en diminuant l'activité de leurs mitochondries, afin d'augmenter la disponibilité des ressources énergétiques utiles aux neurones.Résumé :La remarquable efficacité du cerveau à compiler et propager des informations coûte au corps humain 20% de son budget énergétique total. Par conséquent, les mécanismes cellulaires responsables du métabolisme énergétique cérébral se sont adéquatement développés pour répondre aux besoins énergétiques du cerveau. Les dernières découvertes en neuroénergétique tendent à démontrer que le site principal de consommation d'énergie dans le cerveau est situé dans les processus astrocytaires qui entourent les synapses excitatrices. Un nombre croissant de preuves scientifiques a maintenant montré que le transport astrocytaire de glutamate est responsable d'un coût métabolique important qui est majoritairement pris en charge par une augmentation de l'activité glycolytique. Cependant, les astrocytes possèdent également un important métabolisme énergétique de type mitochondrial. Par conséquent, la localisation spatiale des mitochondries à proximité des transporteurs de glutamate suggère l'existence d'un mécanisme régulant le métabolisme énergétique astrocytaire, en particulier le métabolisme mitochondrial.Afin de fournir une explication à ce paradoxe énergétique, nous avons utilisé des techniques d'imagerie par fluorescence pour mesurer les modifications de concentrations ioniques spontanées et évoquées par une stimulation glutamatergique dans des astrocytes corticaux de souris. Nous avons montré que les mitochondries d'astrocytes au repos manifestaient des changements individuels, spontanés et sélectifs de leur potentiel électrique, de leur pH et de leur concentration en sodium. Nous avons trouvé que le glutamate diminuait la fréquence des augmentations spontanées de sodium en diminuant le niveau cellulaire d'ATP. Nous avons ensuite étudié la possibilité d'une régulation du métabolisme mitochondrial astrocytaire par le glutamate. Nous avons montré que le glutamate initie dans la population mitochondriale une augmentation rapide de la concentration en sodium due à l'augmentation cytosolique de sodium. Nous avons également montré que le relâchement neuronal de glutamate induit une acidification mitochondriale dans les astrocytes. Nos résultats ont indiqué que l'acidification induite par le glutamate induit une diminution de la production de radicaux libres et de la consommation d'oxygène par les astrocytes. Ces études ont montré que les mitochondries des astrocytes sont régulées individuellement et adaptent leur activité selon l'environnement intracellulaire. L'adaptation dynamique du métabolisme énergétique mitochondrial opéré par le glutamate permet d'augmenter la quantité d'oxygène disponible et amène au relâchement de lactate, tous deux bénéfiques pour les neurones.Abstract :The remarkable efficiency of the brain to compute and communicate information costs the body 20% of its total energy budget. Therefore, the cellular mechanisms responsible for brain energy metabolism developed adequately to face the energy needs. Recent advances in neuroenergetics tend to indicate that the main site of energy consumption in the brain is the astroglial process ensheating activated excitatory synapses. A large body of evidence has now shown that glutamate uptake by astrocytes surrounding synapses is responsible for a significant metabolic cost, whose metabolic response is apparently mainly glycolytic. However, astrocytes have also a significant mitochondrial oxidative metabolism. Therefore, the location of mitochondria close to glutamate transporters raises the question of the existence of mechanisms for tuning their energy metabolism, in particular their mitochondrial metabolism.To tackle these issues, we used real time imaging techniques to study mitochondrial ionic alterations occurring at resting state and during glutamatergic stimulation of mouse cortical astrocytes. We showed that mitochondria of intact resting astrocytes exhibited individual spontaneous and selective alterations of their electrical potential, pH and Na+ concentration. We found that glutamate decreased the frequency of mitochondrial Na+ transient activity by decreasing the cellular level of ATP. We then investigated a possible link between glutamatergic transmission and mitochondrial metabolism in astrocytes. We showed that glutamate triggered a rapid Na+ concentration increase in the mitochondrial population as a result of plasma-membrane Na+-dependent uptake. We then demonstrated that neuronally released glutamate also induced a mitochondrial acidification in astrocytes. Glutamate induced a pH-mediated and cytoprotective decrease of mitochondrial metabolism that diminished oxygen consumption. Taken together, these studies showed that astrocytes contain mitochondria that are individually regulated and sense the intracellular environment to modulate their own activity. The dynamic regulation of astrocyte mitochondrial energy output operated by glutamate allows increasing oxygen availability and lactate production both being beneficial for neurons.
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Gene expression signatures are used in the clinic as prognostic tools to determine the risk of individual patients with localized breast tumors developing distant metastasis. We lack a clear understanding, however, of whether these correlative biomarkers link to a common biological network that regulates metastasis. We find that the c-MYC oncoprotein coordinately regulates the expression of 13 different "poor-outcome" cancer signatures. In addition, functional inactivation of MYC in human breast cancer cells specifically inhibits distant metastasis in vivo and invasive behavior in vitro of these cells. These results suggest that MYC oncogene activity (as marked by "poor-prognosis" signature expression) may be necessary for the translocation of poor-outcome human breast tumors to distant sites.
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Some authors argue that both substance dependence and eating disorders should be considered as dependent behaviours. Similarities and differences between these disorders, however, remain unclear. This study compares processes of emotion regulation in adolescents and young adults (15 to 25 years old) with substance dependence (SD) or eating disorders (ED). One hundred and thirteen SD, 50 ED and 86 non-clinical subjects (NC), recruited in four French and Swiss locations, completed a self-report questionnaire of emotion regulation strategies. This questionnaire addresses the subjects' relationships, concerning past and present family, and refers to Main's (1990) concept of primary strategy (balanced activation and deactivation of attachment behaviours), and of secondary strategies (hyperactivation or excessive deactivation of the attachment system). Participants were also questioned in structured interviews, about life events and DSM-IV classification criteria. SD reported more adverse events than ED and NC. SD and ED reported using fewer primary strategies than NC, and SD had secondary strategies that were different from those of ED. Patients with eating disorders reported more hyperactivation, and SD reported more deactivation of the attachment system. It is hypothesized that while subjects with SD and ED have in common poorly regulated strategies, they differ in the way they process emotion or relationship-related information.
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We use store-specific data for a major UK supermarket chain to estimate the impact of planning on store output. Using the quasi-natural experiment of the variation in policies between England and other UK countries, we isolate the impact of Town Centre First policies. We find that space contributes directly to store productivity; and planning policies in England directly reduce output both by reducing store sizes and forcing stores onto less productive sites. We estimate that since the late 1980s planning policies have imposed a loss of output of at least 18.3 to 24.9% - more than a “lost decade’s” growth. JEL codes: D2, L51, L81, R32.
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The focus of this report is the regulation of complementary therapists and, as such, does not deal directly with the efficacy of such therapies. It is for the consumer to make the choice of which therapy they intend to use. Whether they wish to consult a qualified therapist such as a homeopath or an acupuncturist, a healer, the seventh son of a seventh son, a person reputed to have a cure for a particular ailment or a person with a special skill with bones; the choice is theirs. Read the report (PDF 607kb) Download the accompanying leaflet (PDF 300kb) Note – Re: Page 70. ASK Ireland wish to clarify that the Kinesiology Association of Ireland do not represent the Association of Systematic Kinesiology in Ireland, in any way.