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Os hormônios tireoideanos e o desenvolvimento esquelético fetal e pós-natal: estudo do padrão de expressão dos transportadores e das selenodesiodases das iodotironinas. / Thyroid hormone and skeletal development at fetal and postnatal ages: the expression pattern of iodothyronine transporters and deiodinases.Capelo, Luciane Portas 09 February 2009 (has links)
Ainda não é claro o papel dos hormônios tireoideanos (HT) no desenvolvimento do esqueleto fetal. Para responder a questão, induzimos hipotireoidismo materno e fetal em camundongos prenhes através da administração de metimazol e perclorato de sódio. O esqueleto fetal apresentou discretas morfológicas até 16,5 dias de idade embrionária (E). Apenas no final da gestação, em 18,5E, foram observadas a redução significativa da zona hipertrófica, do número de condrócitos hipertróficos, desorganização e diminuição da quantidade dos condrócitos proliferativos, além da redução da expressão do colágeno I, X e osteocalcina. Os TRs, assim como LAT1, LAT2 e MCT8 foram detectados em todas as idades estudadas. A alta expressão gênica da D3, principal inativadora do hormônio tireoideano, em 14,5E e sua redução significativa durante o desenvolvimento, até atingir níveis indetectáveis no período pós-natal indicam que a D3 seja responsável por manter baixos níveis de HT no esqueletono início da gestação, garantindo um desenvolvimento ósseo normal. / Thyroid hormone (TH) plays a key role on post-natal bone development and metabolism, while its relevance during fetal bone development is uncertain. To study this, pregnant mice and fetuses were made hypothyroid. The skeleton morphology was preserved up to 16.5 embryonic days (E). Only at E18.5, the hypothyroid fetuses exhibited a reduction in femoral type I and type X collagen and osteocalcin mRNA levels, in the length and area of the proliferative and hypertrofic zones, in the number of chondrocytes per proliferative column, and in the number of hypertrophic chondrocytes. This suggests that up to E16.5, thyroid hormone signaling in bone is kept to a minimum. D3 mRNA was readily detected as early as E14.5 and its expression decreased markedly at E18.5, and even more after birth. The expression levels of D3 gene during early bone development along with the absence of a hypothyroidism-induced bone phenotype at this time suggest that its expression keeps thyroid hormone signaling in bone to very low levels at this early stage of bone development.
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Optimisation pharmacologique des dérivés de la créatine pour le traitement du déficit en transporteur de la créatine / Chemical optimization of creatine derivatives for the treatment of creatine transporter deficiencyTrotier-Faurion, Alexandra 29 March 2013 (has links)
Le déficit en transporteur de la créatine est une maladie rare neurologique dans laquelle la perte de fonctionnalité du transporteur de la créatine (SLC6A8) conduit à une absence de créatine au niveau cérébral et à des retards de développement majeurs chez les enfants. A l’heure actuelle, aucune thérapie efficace n’est disponible.Une approche thérapeutique potentielle est le développement de molécules prodrogues de la créatine plus lipophiles qui franchiront les membranes cellulaires de façon passive et la recherche d’une formulation galénique susceptible d’emmener la prodrogue vers les cellules cibles d’intérêt, les neurones. Ainsi, dans cette thèse, nous proposons une nouvelle voie de synthèse originale d’esters de la créatine à longue chaîne aliphatique. Ces composés présentent des propriétés pharmacologiques intéressantes : nous montrons qu’il existe une relation de structure-activité entre la taille de la chaîne aliphatique (et donc la lipophilie) et la capacité de la molécule à être internalisée dans les cellules endothéliales cérébrales, astrocytaires et neuronales, constituant l’unité neurovasculaire. Il ressort de nos observations expérimentales que l’ester dodécylique de créatine est le meilleur candidat médicament. De plus, après avoir été internalisé dans les fibroblastes des patients présentant un déficit fonctionnel du transporteur de la créatine, l’ester dodécylique subit une conversion par les estérases cellulaires, libérant ainsi la créatine dans le compartiment intracellulaire.La formulation galénique permettant de protéger ces esters de créatine jusqu’au cerveau repose, elle, sur la nanovectorisation, par encapsulation de l’ester dodécylique de créatine dans des NanoCapsules Lipidiques. L’avantage de cette formulation est de permettre également un ciblage actif vers la Barrière Hémato-Encéphalique, obstacle majeur dans le développement de thérapies ciblant le Système Nerveux Central. Nos observations expérimentales mettent en exergue cette double stratégie thérapeutique pour le traitement du déficit en transporteur de la créatine.Ce travail a été soutenu financièrement par la Fondation Lejeune. / Creatine transporter deficiency is a rare brain disease associated with the loss of function of the SLC6A8 (creatine transporter) leading to an absence of creatine at the cerebral level and to a dramatic neurodevelopmental retardation in the children. To date, no effective therapy is available.A potential therapeutic option would be the design of a pharmaceutical formulation of lipophilic prodrugs of creatine that will cross the cell membranes passively and target the neurons in order to restore the creatine content inside these cells.One of the main purposes of this dissertation is to propose an original chemistry synthesis process of creatine esters with long aliphatic chain. These compounds show interesting pharmacological properties of structure-activity relationship between the length of the aliphatic chain (i.e. lipophilicity) and the ability for the drug to enter cerebral endothelial, astroglial and neuronal cells. According to our experimental observations, the dodecyl ester creatine seems to be the best drug candidate. Moreover, the dodecyl ester is acted on by cellular esterases inside patients’ fibroblasts with a functional deficit of the SLC6A8 and increases the intracellular creatine content.The pharmaceutical formulation developed in this study consists by incorporation of dodecyl ester inside a nanovector (Lipid NanoCapsules). Two main advantages can be gained by nanovectorization: firstly, the dodecyl ester is protected from the degradation by plasmatic esterases before reaching the brain. Secondly, the nanovectorization strategy is highly valuable to brain targeting bypassing the blood-brain barrier, which remains until now a major impediment in the drug design for the Central Nervous System. Our experimental observations highlight this two-step therapeutic strategy for the treatment of deficiency of the creatine transporter.This work was financially supported by the International PhD Program of the Life Sciences division of the CEA and the Fondation Jérôme Lejeune.
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Etude des protéines à motif PQ : Identification d'un nouveau transporteur lysosomal impliqué dans le traitement de la cystinose et analyse bioinformatique de la famille protéique / PQ-loop Protein Study : Identification of a New Lysosomal Transporter Involved in Cystinosis Treatment and Bioinformatic Analysis of its Proteic FamilyJézégou, Adrien 25 November 2014 (has links)
Le transport de composés à travers les membranes biologiques est crucial pour la physiologie des cellules eucaryotes. Cependant la fonction de nombreux transporteurs putatifs reste inconnue. C’est notamment le cas de nombreux transporteurs intracellulaires exportant les catabolites du lysosome. Le transporteur lysosomal de cystine, baptisé cystinosine, se caractérise par la présence d’un motif dupliqué appelé " boucle PQ ". Sa dysfonction entraîne une maladie lysosomale, la cystinose, caractérisée par l'accumulation de cystine dans les lysosomes. Les protéines possédant un motif PQ sont retrouvées plus souvent dans les cellules eucaryotes et, à l'exception de la cystinosine, leur fonction reste inconnue. Dans cette thèse, nous démontrons qu'une autre protéine à motif PQ, PQLC2 est le transporteur responsable de l'efflux lysosomal des acides aminés cationiques et qu'il est impliqué dans le traitement de la cystinose.L'hypothèse de départ était basée, d'une part, par sur des prédictions par analyse protéomique de la localisation lysosomale de PQLC2 et, d'autre part, sur des résultats chez S.cerevisiae impliquant les orthologues putatifs de PQLC2, situés à la membrane de la vacuole, dans l'homéostasie des acides aminés cationiques. En utilisant une approche consistant à délocaliser PQLC2 à la membrane plasmique et à acidifier le pH extracellulaire pour mimer la lumière acide du lysosome, nous avons pu, par mesure d'accumulation intracellulaire de composés radiomarqués et par mesure électrophysiologique sur cellule entière, faire la preuve du transport sélectif, actif à bas pH et de faible affinité des acides aminés cationiques par PQLC2. Dans une seconde partie, nous avons mis en évidence l'implication de ce transporteur dans l'efflux lysosomal du produit de réaction entre la cystine accumulée dans les lysosomes de cellules de patients cystinotiques et le principe actif (cystéamine) du traitement pharmacologique de la cystinose.Enfin, dans une dernière partie, nous avons effectué une analyse bioinformatique préliminaire des protéines à motif PQ qui exploitait la pseudo-symétrie de ces protéines pour identifier des résidus potentiellement impliqués dans l'activité de transport. / Transport of solutes across biological membranes is crucial to eukaryotic cell physiology. However, the function of many putative transporters remains unknown, such as the proteins responsible for lysosomal export of metabolites. Cystinosin, the lysosomal cystine exporter defective in cystinosis, is characterized by a duplicated motif termed the PQ loop. PQ-loop proteins are more frequent in eukaryotes than in prokaryotes, and, except for cystinosin, their molecular function remains unknown. Here we show that another PQ-loop protein, PQLC2, is a lysosomal transporter for cationic amino acids and that it is required for the treatment of cystinosis. The hypothesis that PQLC2 is a lysosomal metabolite transporter was based on a proteomic study predicting that PQLC2 is located at the lysosomal membrane and on a genetic study that linked putative yeast orthologues with cationic amino acid homeostasis. Using an approach that consisted in misrouting PQLC2 to the plasma membrane of frog oocytes and in acidifying the extracellular medium to mimic the acidic lysosomal lumen, we showed an accumulation of radiolabelled cationic amino acids into mRNA-injected oocytes and an electrogenic, inward current due to a selective, pH-dependent, low-affinity transport of cationic amino acids by PQLC2. Moreoever, we showed that PQLC2 exports a key chemical intermediate (cysteamine-cysteine mixed disulfide) from cystinotic lysosomes treated with the aminothiol drug cysteamine, thus explaining the mechanism underlying the current drug therapy of cystinosis. Finally, in a last chapter, we performed a preliminary bioinformatic study of the family of PQ-loop proteins that took advantage of the pseudo-symmetric structure of these proteins to identify residues potentially important for the transport activity.
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Synthetic strategies for potential trypanocidesCapes, Amy January 2011 (has links)
Human African trypanosomiasis (sleeping sickness) is a devastating disease which is endemic in parts of sub-Saharan Africa. It is caused by the protozoan parasite T. brucei, which are transmitted by the bite of infected tsetse flies. Although the disease is fatal if left untreated, there is a lack of safe, effective and affordable drugs available; therefore new drugs are urgently needed. The aim of the work presented in this thesis is to develop novel trypanocidal compounds. It is divided into two parts to reflect the two distinct strategies employed to achieve this aim. The first part focuses on the inhibition of glycophosphoinositol (GPI) anchor synthesis by inhibiting the Zn2+-dependent enzyme, GlcNAc-PI de-N-acetylase. Trypanosomes have a variable surface glycoprotein (VSG) coat, which allows them to evade the human immune system. The GPI anchor attaches the VSG to the cell membrane; therefore inhibiting GPI synthesis should expose the parasite to the immune system. Initially, large substrate analogues were synthesized. These showed weak inhibition of the enzyme. Zinc-binding fragments were screened, and small molecule inhibitors based on salicylhydroxamic acid were then synthesized. These compounds showed modest inhibition, but the excellent ligand efficiency of salicylhydroxamic acid indicates this may be a promising starting point for further inhibitors. The second part details the P2 strategy. The P2 transporter is a nucleoside transporter unique to T. brucei, which concentrates adenosine. The transporter also binds and selectively concentrates compounds that contain benzamidine and diaminotriazine P2 motifs, which can enhance the potency and selectivity of these compounds. The sleeping sickness drugs melarsoprol and pentamidine contain P2 motifs. Compounds comprising a P2 targeting motif, a linker and a trypanocidal moiety were synthesized. Initially, a diaminotriazine P2 motif was attached to a trypanocidal tetrahydroquinoline (THQ) protein farnesyl transferase (PFT) inhibitor, with limited success. The P2 strategy was also applied to a non-selective, trypanocidal, quinol moiety. The quinol moiety was attached to diaminotriazine and benzamidine P2 motifs, and an increase in selectivity for T. brucei over MRC5 cells was observed.
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Análise do metabolismo de polifosfato e do operon pst em Pseudomonas aeruginosa. / Analysis of the metabolism of polyphosphate and of the pst operon in Pseudomonas aeruginosa.Munevar, Nicolas Federico Villamil 06 August 2015 (has links)
O operon pst de P. aeruginosa codifica um transportador de fosfato de alta afinida-de e também a proteína PhoU que, em conjunto, atuam como repressores da ex-pressão do regulon Pho dessa espécie. A atividade de PhoU está também associada ao metabolismo de polifosfato (poliP), dado que mutantes phoU nulos apresentam um vasto acúmulo do biopolímero. Ensaios de β-galactosidase mostraram uma alteração na expressão dos genes ppk e ppx, envolvidos no metabolismo de poliP, no mutante phoU. Observou-se que na cepa selvagem, a transcrição de ppk e de ppx não responde às limitações de Pi ou de nitrogênio, sendo esses genes altamente expressos em condições normais de crescimento. Além disso, determinou-se que ppk é co-transcrito com o gene hemB, os quais formam, portanto, um operon. O operon pst também foi analisado. Foi identificado por ensaios de northern blot o transcrito do primeiro gene do operon, pstS, que codifica uma proteína periplasmática. Também, foi identificado um promotor imediatamente a montante de phoU, o gene mais distal do operon, que permitiria sua expressão em condições normais do crescimento bacteriano. Por fim, determinou-se por ensaios de EMSA que as duas sequências consenso Pho box presentes no operon pst são completamente funcionais. / The pst operon in P. aeruginosa encodes a high-affinity phosphate transporter and the PhoU protein, which together act as repressors of Pho regulon of this species. The PhoU activity is also related with polyphosphate (polyP) metabolism, since phoU null mutants have a large accumulation of the biopolymer. β-galactosidase assays allowed to confirm a change in the expression of ppk and ppx genes, in-volved in PolyP metabolism, in the phoU mutant. It was also evidenced that in the wild type strain, the ppk and ppx transcription does not respond to Pi or nitrogen starvation, and that these genes are highly expressed under conditions of normal growth. In addition, it was determined that ppk is co-transcribed with hemB, a gene involved in the synthesis of porphyrins, and they constitute therefore an operon. The pst operon was also examined. Was identified by northern blot the transcript of the first gene in the operon, pstS, which encodes a periplasmic protein. Also, a promoter was identified immediately upstream of phoU, the most distal gene in the operon, allowing its expression in normal conditions of bacterial growth. Finally, it was determined by EMSA that the two consensus sequences Pho box present in the pst operon are fully functional.
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Implication des récepteurs de la mélatonine dans les troubles neurologiques et le diabète de type 2 et identification de régions clés du récepteur MT1 responsables de sa sélectivité fonctionnelleHégron, Alan 10 1900 (has links)
No description available.
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Samarbeten vid outsourcing av logistiska funktioner : En kvalitativ intervjustudie av samarbeten inom svenska företag som outsourcar sin distribution / Relationships that arise when companies outsource logistic functions : A qualitative interview study of collaborations within Swedish companies that outsource their distributionGreijer, Jonna, Sillrén, Frida January 2019 (has links)
Inom företag sker en mängd olika logistiska aktiviteter. Det kan bland annat handla om inköp av råmaterial, produktion, materialhantering, lagerhållning eller distribution av varor till slutkund. Producerande företag måste ta ställning till flera olika alternativa logistiklösningar för att genomföra dessa aktiviteter. Ett av alternativen som företag kan använda sig utav är outsourcing. Företag kan förutom att utföra aktiviteter inom företaget även välja att ta beslutet att outsourca vilket innebär att vissa av deras aktiviteter läggas över på externa parter som överlåts ett visst ansvar. Outsourcing kan ske i olika grad samt utformas på olika sätt. När ett företag väljer att outsourca en eller flera logistikfunktioner uppstår ett partnerskap mellan det egna företag och företaget som erbjuder tjänsten. Syftet med rapporten är att skapa en djupare förståelse över hur samarbetet kan se ut mellan ett producerande företag som outsourcar delar av sin distribution och företaget som erbjuder tjänsten. Avsikten är att genomföra en jämförelse mellan vad litteraturen samt vad företag i praktiken visar samt utifrån det genomföra en analys. Intervjustudien som genomförs ska visa hur samarbeten utformas mellan de intervjuade företagen och deras outsourcingleverantörer för att sedan kunna beskriva vilka typer av samarbeten som kan utformas vid dessa typer av outsourcingrelationer. Resultatet av rapporten visar att företag som outsourcar baserar sitt val av leverantör på finansiell stabilitet, att leverantören har rätt utrustning och kapacitet, speciell kunskap om det gods som ska hanteras, hållbarhet, kostnad, kvalitetskrav (leveranssäkerhet) samt ryktet som leverantören har. De vanligast förekommande samarbetet är det som sker på armlängdsavstånd/ kostnadsstadiet. Det förekommer även samarbeten i form av partnerskap på grundnivå och semi-utvecklat partnerskap/ resursstadiet. Det finns även fulltutvecklat partnerskap/ partnerskapsstadiet, Joint ventures/ partnerskapsstadiet samt vertikal integration men dessa går inte att uppnå vid outsourcing av enbart transport och/eller lager. Faktorer som bidrar till att samarbeten blir lyckade är tydligt utformade kontrakt, tydlig och öppen kommunikation, bygga partnerskap, tydliga mått och en kontinuerlig utvärdering av leverantörens prestation. / Within companies, a variety of logistic activities take place. This may include purchasing raw materials, production, material handling, warehousing or distribution of goods to customers. Producing companies must take a stand on several different alternative logistics solutions to carry out these activities. One of the options that companies can use is outsourcing. Companies can, in addition to carrying out activities within the company, also choose to take the decision to outsource, which means that some of their activities are transferred to external parties who are assigned a certain responsibility. Outsourcing can take place in varying degrees and be designed in different ways. When a company chooses to outsource one or more logistics functions, a partnership arises between the company that is outsourcing and the company that offers the service. The purpose of the report is to develop a deeper understanding of how the collaboration can look between a producing company that outsources parts of its distribution and the company that offers the service. The intention of the study is to make a comparison between what the literature and what Swedish companies indicate and then conduct an analysis. The interview study conducted will show how collaboration is formed between the interviewed companies and their outsourcing suppliers in order to be able to describe what types of collaborations can be designed in these types of outsourcing relationships. The result of the report indicates that companies that outsource base their choice of supplier on financial stability, that the supplier has the right equipment and capacity, special knowledge of the goods that will be distributed, sustainability, cost, quality requirements (delivery reliability) and the reputation of the supplier. The most common cooperation is that of arm's length distance/ cost stage. There are also collaborations in the form of partnerships at the basic level and the semi-developed partnership/ resource stage. There is also a fully developed partnership/ partnership stage, the joint ventures/ partnership stage and vertical integration, but these cannot be achieved when outsourcing only transport and/or warehouse functions. Factors that enables a successful collaboration are clearly designed contracts, clear and open communication, building partnerships, clear measures, and continuous evaluation of vendor performance.
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ATP-Binding Cassette Efflux Transporters and Passive Membrane Permeability in Drug Absorption and DispositionMatsson, Pär January 2007 (has links)
<p>Transport into and across the cells of the human body is a prerequisite for the pharmacological action of drugs. Passive membrane permeability and active transport mechanisms are major determinants of the intestinal absorption of drugs, as well as of the distribution to target tissues and the subsequent metabolism and excretion from the body. In this thesis, the role of ATP-binding cassette (ABC) transporters and passive permeability on drug absorption and disposition was investigated. Particular emphasis was placed on defining the molecular properties important for these transport mechanisms. </p><p>The influence of different transport pathways on predictions of intestinal drug absorption was investigated using experimental models of different complexity. Experimental models that include the paracellular pathway gave improved predictions of intestinal drug absorption, especially for incompletely absorbed drugs. Further, the inhibition of the ABC transporters breast cancer resistance protein (BCRP/ABCG2) and multidrug-resistance associated protein 2 (MRP2/ABCC2) was experimentally investigated using structurally diverse datasets that were representative of orally administered drugs. A large number of previously unknown inhibitors were identified among registered drugs, but their clinical relevance for drug-drug interactions and drug-induced toxicity remains to be determined. The majority of the inhibitors affected all three major ABC transporters BCRP, MRP2 and P-glycoprotein (P gp/ABCB1), and these multi-specific inhibitors were found to be enriched in highly lipophilic weak bases. </p><p>To summarize, the present work has led to an increased knowledge of the molecular features of importance for ABC transporter inhibition and passive membrane permeability. Previously unknown ABC transporter inhibitors were identified and predictive computational models were developed for the different drug transport mechanisms. These could be valuable tools to assist in the prioritization of experimental efforts in early drug discovery.</p>
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En hållbar trafiklösning för nya Slussen? : Uppfattningar om hållbarhet och hållbar stadsutveckling i SlussenprojektetBjarnestam, Jesper January 2011 (has links)
This thesis examines perceptions of sustainability and sustainable urban development among actors involved in the project of rebuilding Slussen in central Stockholm. Views on the suggested new traffic solution and what would make a sustainable solution, the concepts of sustainability and sustainable urban development and how these concepts are interpreted and applied as policy, are especially investigated. A semi-structured qualitative interview study has been carried out and the respondents include city officials, politicians, representatives of interest groups, consultants and researchers. Stockholm, European Green Capital in 2010, sets high goals for sustainability. As concept, sustainability is also frequently used in much of the city´s planning material such as the budget, environmental programme and urban development documents. However, it has not been included in the goals of the Slussen project. Even though, interviewees representing the city view the project as a sustainability project whereas other respondents clearly question this view. The study suggests that a determining factor for this division is how the sustainability concept is defined (or not), also how car traffic is viewed in urban sustainable development. The thesis shows that instead of planning for sustainable transportation, traditional business-as-usual traffic planning has dominated the Slussen project. The main reasons are that the new traffic solution, although including new walking and cycling bridges as well as a new bus terminal, includes planning for increased car traffic, an eight lane bridge to provide for it and a high degree of separation instead of integration of transport modes. Many of the interviewees also perceive of the suggested new main bridge as a motorway and the walking bridge as being both socially and culturally unsustainable in its long and narrow design. The new traffic solution in itself is viewed as unsustainable since it would bring about the abandonment of a more than 300 year old tradition of double and equal bridges at Slussen. Finally, the study suggests that the planned new traffic solution would have both looked different and been perceived of as more sustainable if sustainability had been included in the project goals. However, this would only have been the case if the concept was properly defined and implemented.
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ATP-Binding Cassette Efflux Transporters and Passive Membrane Permeability in Drug Absorption and DispositionMatsson, Pär January 2007 (has links)
Transport into and across the cells of the human body is a prerequisite for the pharmacological action of drugs. Passive membrane permeability and active transport mechanisms are major determinants of the intestinal absorption of drugs, as well as of the distribution to target tissues and the subsequent metabolism and excretion from the body. In this thesis, the role of ATP-binding cassette (ABC) transporters and passive permeability on drug absorption and disposition was investigated. Particular emphasis was placed on defining the molecular properties important for these transport mechanisms. The influence of different transport pathways on predictions of intestinal drug absorption was investigated using experimental models of different complexity. Experimental models that include the paracellular pathway gave improved predictions of intestinal drug absorption, especially for incompletely absorbed drugs. Further, the inhibition of the ABC transporters breast cancer resistance protein (BCRP/ABCG2) and multidrug-resistance associated protein 2 (MRP2/ABCC2) was experimentally investigated using structurally diverse datasets that were representative of orally administered drugs. A large number of previously unknown inhibitors were identified among registered drugs, but their clinical relevance for drug-drug interactions and drug-induced toxicity remains to be determined. The majority of the inhibitors affected all three major ABC transporters BCRP, MRP2 and P-glycoprotein (P gp/ABCB1), and these multi-specific inhibitors were found to be enriched in highly lipophilic weak bases. To summarize, the present work has led to an increased knowledge of the molecular features of importance for ABC transporter inhibition and passive membrane permeability. Previously unknown ABC transporter inhibitors were identified and predictive computational models were developed for the different drug transport mechanisms. These could be valuable tools to assist in the prioritization of experimental efforts in early drug discovery.
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