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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

INVESTIGAÇÃO DE MODY 3 EM PACIENTES DO AMBULATÓRIO DE DM 1 DO HOSPITAL UNIVERSITÁRIO DA UNIVERSIDADE FEDERAL DO MARANHÃO (HUUFMA) / INVESTIGATION OF MODY 3 IN PATIENTS OF THE AMBULATORY OF DM 1 OF UNIVERSITY HOSPITAL OF THE FEDERAL UNIVERSITY OF MARANHÃO (HUUFMA)

Almeida, Ana Gregória Ferreira Pereira de 16 March 2012 (has links)
Made available in DSpace on 2016-08-19T18:16:07Z (GMT). No. of bitstreams: 1 Dissertacao Ana Gregoria.pdf: 3461170 bytes, checksum: 243ffe696e34289efe111c11281cd8e7 (MD5) Previous issue date: 2012-03-16 / Maturity onset diabetes of young 3 (MODY 3) is the most common monogenic autosomal dominant diabetes caused by mutations in the HNF 1A and characterized by a defect in insulin secretion, decreased renal threshold for glucose and sensitivity to sulfonureia. It is often misdiagnosed as DM 1 or DM 2. By this evidence, this study aims to investigate the HNF 1A gene mutations in patients treated at the outpatient clinic of the University Hospital of DM1 UFMA Sao Luis - MA (HUUFMA), characterize epidemiologically the study population, and identify and describe the mutations found in the gene, correlating them with the chronic complications of diabetes that these patients may have. We evaluated by questionnaire 60 patients with a previous diagnosis of DM 1. These, 20 patients were selected for their clinical features suggestive of MODY for molecular analysis of the HNF 1A gene by sequencing technique. Eleven patients were females and nine males with a mean age of 24.35 ± 6.91 years. Twenty five per cent had retinopathy, 55 %, nephropathy, neuropathy 35 % and 15 % ischemic heart disease. Among the gene variations were found 53 mutations, of these, a deletion in the promoter. Of the 52 variations that occurred in exons, 15 were silent. Among the non- silent, there were 29 missense mutations, seven deletions and one nonsense. Of these, 11 mutations were found in the A isoform, two in the AB isoform and 24 in the ABC isoform. Regarding the fields of protein, it was found: one missense mutation in the dimerization domain, nine mutations in the DNA-binding domain and 25 mutations in the transactivation domain. By correlating the types of mutations, their locations in their respective gene or protein domains with typical chronic complications of diabetes, there was no relationship. However, it was observed that patients with frameshift mutations associated with missense mutations in the transactivation domain had a worse metabolic control than patients with missense mutations in the same domain. With these results we conclude that changes in gene HNF 1A are very common among diabetic patients with a typical characteristics of MODY in this sample, suggesting that the MODY 3 can be cause of DM in many of these patients and the type of mutation and its location in the field protein may be associated with metabolic control in these patients. / Maturity onset diabetes of young 3 (MODY 3)é o mais frequente diabetes mellitus (DM) monogênico autossômico dominante causado por mutações no gene HNF 1A e caracterizado por defeito na secreção de insulina, diminuição no limiar renal de glicose e sensibilidade a sulfonureia, na maioria das vezes. Com frequência é diagnosticado erroneamente como DM 1 ou DM 2. Frente a esta evidência este trabalho tem como objetivo a investigação das mutações do gene HNF 1A em pacientes atendidos no ambulatório de DM1 do Hospital Universitário da UFMA São Luís MA (HUUFMA), assim como caracterizar epidemiologicamente a população de estudo, além de identificar e descrever as mutações encontradas no gene, correlacionando-as com as complicações crônicas próprias do DM que estes pacientes possam apresentar. Foram avaliados por meio de questionário 60 pacientes com diagnóstico prévio de DM 1, destes, 20 pacientes foram selecionados por suas características clínicas sugestivas de MODY para análise molecular do gene HNF 1A pela técnica de sequenciamento. Onze pacientes foram do sexo feminino e nove do sexo masculino com uma média de idade de 24,35 ± 6,91 anos. Destes, 25% apresentavam retinopatia, 55%, nefropatia, 35% neuropatia e 15% cardiopatia isquêmica. Dentre as variações gênicas, foram encontradas 53 mutações, destas, uma deleção no promotor. Das 52 variações que ocorreram nos éxons, 15 eram silenciosas. Entre as não-silenciosas, observaram-se 29 missense, sete deleções e uma nonsense. Destas, 11 mutações encontraram-se na isoforma A, duas na isoforma AB e 24 na isoforma ABC. Em relação aos domínios da proteína, verificou-se: uma mutação missense no domínio de dimerização, nove mutações no domínio de ligação do DNA e 25 mutações no domínio de transativação. Ao se correlacionar os tipos de mutações, suas localizações no gene ou em seus respectivos domínios de proteína com as complicações crônicas típicas do DM, não se observou qualquer relação. Contudo, foi observado que pacientes apresentando associação de mutações frameshift com missense no domínio de transativação apresentavam um pior controle metabólico que pacientes com mutações missense no mesmo domínio. Com estes resultados concluímos que alterações no gene HNF 1A são muito frequentes entre os paciente com DM 1 com características típicas de MODY, sugerindo que o MODY 3 possa ser causa do DM de muitos destes pacientes e que o tipo de mutação e sua localização no domínio de proteína pode ter associação com o controle metabólico destes pacientes.
2

Ligand binding proteins: roles in ligand transfer and activation of nuclear receptors

Petrescu, Anca Daniela 30 September 2004 (has links)
Cholesterol and fatty acyl-coenzymeA thioesters are signalling molecules with role in regulation of genes involved in lipid and glucose transport and metabolism. The studies described herein focused on three proteins that bind lipids and have different cellular functions: steroidogenic acute regulatory protein (StAR), hepatocyte nuclear factor-4a (HNF-4a) and acyl-CoA binding protein (ACBP). First, StAR mediates delivery of cholesterol to inner mitochondrial membrane in steroidogenesis by a poorly understood mechanism. In our studies, fluorescent NBD-cholesterol binding assays demonstrate that StAR binds cholesterol at two binding sites with 32 nM Kds and circular dichroism spectra show that cholesterol binding results in changes of StAR secondary structure. Fluorescent sterol exchange assays between donor and acceptor mitochondrial membranes indicate that StAR significantly increased the formation of rapidly transferable cholesterol domains. Second, HNF-4a, a nuclear receptor, had been shown to bind fatty acyl-CoAs as natural ligands with apparent low affinities obtained with radiolabeled ligand binding assays. Our fluorescence spectroscopy studies demonstrate that HNF-4a ligand binding domain (HNF-4aLBD) binds acyl-CoAs at a single binding site with Kds of 1.6-4 nM. Fluorescence resonance energy transfer (FRET) between HNF-4aLBD tryptophan residues and cis-parinaroyl-CoA yielded an intermolecular distance of 42 Â thus pointing to direct molecular interaction. Third, although ACBP has been detected in the nucleus, it is not known whether ACBP may directly and/or functionally interact with a nuclear acyl-CoA binding protein such as HNF-4a to regulate transcription. Our present studies in vitro and in intact cultured cells, including circular dichroism of HNF-4a in the presence of ACBP, coimmunoprecipitation of HNF-4a/ACBP complexes, ACBP and HNF-4a colocalization in nuclei of cells by confocal microscopy demonstrate a physical association of ACBP and HNF-4a. FRET microscopy data indicated an intermolecular distance of 53 Â between ACBP and HNF-4a in rat hepatoma cells. Functional assays (transactivation of an HNF4a-dependent reporter gene) showed significant increase in the presence of ACBP in two different cell lines. Expression of ACBP anti-sense RNA decreased HNF-4a-mediated transactivation, pointing to a role of ACBP in co-regulating HNF-4a-dependent transcription.
3

Ligand binding proteins: roles in ligand transfer and activation of nuclear receptors

Petrescu, Anca Daniela 30 September 2004 (has links)
Cholesterol and fatty acyl-coenzymeA thioesters are signalling molecules with role in regulation of genes involved in lipid and glucose transport and metabolism. The studies described herein focused on three proteins that bind lipids and have different cellular functions: steroidogenic acute regulatory protein (StAR), hepatocyte nuclear factor-4a (HNF-4a) and acyl-CoA binding protein (ACBP). First, StAR mediates delivery of cholesterol to inner mitochondrial membrane in steroidogenesis by a poorly understood mechanism. In our studies, fluorescent NBD-cholesterol binding assays demonstrate that StAR binds cholesterol at two binding sites with 32 nM Kds and circular dichroism spectra show that cholesterol binding results in changes of StAR secondary structure. Fluorescent sterol exchange assays between donor and acceptor mitochondrial membranes indicate that StAR significantly increased the formation of rapidly transferable cholesterol domains. Second, HNF-4a, a nuclear receptor, had been shown to bind fatty acyl-CoAs as natural ligands with apparent low affinities obtained with radiolabeled ligand binding assays. Our fluorescence spectroscopy studies demonstrate that HNF-4a ligand binding domain (HNF-4aLBD) binds acyl-CoAs at a single binding site with Kds of 1.6-4 nM. Fluorescence resonance energy transfer (FRET) between HNF-4aLBD tryptophan residues and cis-parinaroyl-CoA yielded an intermolecular distance of 42 Â thus pointing to direct molecular interaction. Third, although ACBP has been detected in the nucleus, it is not known whether ACBP may directly and/or functionally interact with a nuclear acyl-CoA binding protein such as HNF-4a to regulate transcription. Our present studies in vitro and in intact cultured cells, including circular dichroism of HNF-4a in the presence of ACBP, coimmunoprecipitation of HNF-4a/ACBP complexes, ACBP and HNF-4a colocalization in nuclei of cells by confocal microscopy demonstrate a physical association of ACBP and HNF-4a. FRET microscopy data indicated an intermolecular distance of 53 Â between ACBP and HNF-4a in rat hepatoma cells. Functional assays (transactivation of an HNF4a-dependent reporter gene) showed significant increase in the presence of ACBP in two different cell lines. Expression of ACBP anti-sense RNA decreased HNF-4a-mediated transactivation, pointing to a role of ACBP in co-regulating HNF-4a-dependent transcription.
4

Hepatocyte nuclear factor-1β (HNF-1β) promotes glucose uptake and glycolytic activity in ovarian clear cell carcinoma / HNF-1βは卵巣明細胞腺癌において糖の取り込みと解糖系経路活性を亢進させる

Okamoto, Takako 23 January 2014 (has links)
Final article is available at "wileyonlinelibrary.com" Takako Okamoto, Masaki Mandai, Noriomi Matsumura, Ken Yamaguchi, Hiroshi Kondoh, Yasuaki Amano, Tsukasa Baba, Junzo Hamanishi, Kaoru Abiko, Kenzo Kosaka, Susan K. Murphy, Seiichi Mori, Ikuo Konishi "Hepatocyte nuclear factor-1β (HNF-1β) promotes glucose uptake and glycolytic activity in ovarian clear cell carcinoma" Molecular Carcinogenesis 54:35–49 (2013) / 京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第12804号 / 論医博第2076号 / 新制||医||1001(附属図書館) / 80848 / 京都大学大学院医学研究科医学専攻 / (主査)教授 野田 亮, 教授 武藤 学, 教授 稲垣 暢也 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM
5

Les Particules d'Exopolymères Transparentes (Transparent Exopolymer Particles, TEP) en milieu pélagique lacustre : relation avec le phytoplancton et rôle dans les réseaux trophiques microbiens / Transparent Exopolymer Particles (TEP) in lake pelagic environment : relationship with phytoplankton and role in microbial food webs

Arnous, Mohamad Bashir 16 November 2010 (has links)
Ce travail est une contribution à la connaissance de l’importance des particules de nature polysaccharidique, les TEP (Transparent Exopolymer Particles) ou particules d’Exopolymères Transparentes, en milieu pélagique lacustre.Les différentes études présentées dans ce mémoire se sont essentiellement focalisées sur la distribution de ces particules et leur relation avec le phytoplancton et les autres microorganismes du réseau trophique aquatique en milieu naturel (le lac Pavin, oligo-mésotrophe et le réservoir hypereutrophe de Grangent) et en conditions semi contrôlées(enclos limniques installés sur le lac de Créteil). Les résultats de l’étude printanière au lac Pavin indiquent que la majorité des TEP sont colonisées par les bactéries et que l’intensité de colonisation est fortement liée à la température et diminue avec l’augmentation en taille des particules. La distribution des nanoflagellés hétérotrophes (HNF) est fortement liée à la densité des TEP mais pas à l’intensité de colonisation de ces particules. L’abondance et la surface cumulée de TEP sont significativement plus élevées dans le lac oligo-mésotrophe que dans le réservoir hypereutrophe de Grangent. Les abondances et les concentrations élevées de particules dans le lac Pavin coïncident avec la présence de diatomées de grande taille au printemps et en automne et avec les chlorophycées à la fin de l’été.Dans le réservoir de Grangent les valeurs maximales de TEP coïncident avec le développement de la cyanobactérie Microcystis aeruginosa. Si les TEP augmentent avec la productivité de l’écosystème, la production de ces particules par unité de chlorophylle a dépend de la composition algale et tend à diminuer avec l’augmentation du niveau trophique du milieu. Les résultats issus de la biomanipulation en enclos limniques indiquent que la structure du réseau trophique aquatique (par la présence ou l’absence de poissons planctonophages) influence fortement la distribution,la dynamique et le spectre de taille des TEP. Dans le traitement poisson, l’abondance des TEP, la chlorophylle a et la biomasse des chlorophycées sont fortement corrélées. De par son broutage sur le phytoplancton, le zooplancton a un effet négatif sur les TEP dans le traitement sans poissons mais il contribue sans doute à la formation de TEP e tinfluence le spectre de taille de ces dernières dans ce traitement. Ce travail souligne l’importance des particules de nature polysaccharidique en milieu pélagique lacustre qui doivent être considérées comme une part importante du carbone organique qui transite des producteurs primaires vers les décomposeurs et vers le sédiment. / This work adds to the knowledge of the significance of polysaccharidic detrital particles or TEP (= Transparent Exopolymer Particles) in freshwater pelagic environments. Studies in this thesis have mainly focused on the distribution of TEP and their relationships with phytoplankton and other microorganisms in natural environments (the oligo-mesotrophic Lake Pavin and the hypereutrophic reservoir of Grangent) and in limnetic enclosures (lake of Créteil). The intensity of bacterial colonization during spring in Lake Pavin was strongly related to temperature and decreased with particle size. The abundance of heterotrophic nanoflagellates (HNF) in this lake was more significantly related to the density of the particles than to the density of total bacteria and the intensity of bacterial colonization of TEP, suggesting that TEP is a more important factor for HNF development than attached and free bacteria. The abundance and the total surface area of the particles were significantly higher in the hypereutrophic Lake Grangent than in the mesotrophic Lake Pavin. Maximum TEP density in Lake Pavin was recorded during the spring diatom bloom, while TEP concentration peaked in late summer when the phytoplankton community was largely dominated by small-size chlorophytes with an abundant polysaccharide cell coating. In the hypereutrophic Lake Grangent,maximum values of TEP appeared during the summer development of the cyanobacterium Microcystis aeruginosa. Per cell production of TEP, expressed by the ratio between TEP concentration and chlorophyll a concentration, was significantly higher in the less productive lake and the analysis of the size spectra of the particles indicated a greater proportion of small particles in this lake. TEP therefore appear as more significant for microbial development and aggregates formation in the less productive environment. Results from limnetic enclosures (either dominated by planktivorous fish or fishless) indicated that food-web structure strongly influences the distribution and size spectra of TEP. TEP abundances were related to chlorophyll a concentrations and the biomass of chlorophytes in the fish treatment. As expected by the trophic cascades theory, zooplankton had an indirect negative effect on TEP abundance. Our results suggest, however, that metazoan probably influence the formation and the size spectra of the particles in the fishless treatment. TEP must be regarded as a major part of the organic carbon which is transferred from the primary producers to the microbial food web and the sediments in freshwater ecosystems.
6

Implication des récepteurs nucléaires HNF-4α et HNF-4γ dans la fonction entéroendocrine et la susceptibilité à l'obésité et au diabète de type II / The role of the HNF-4alpha and HNF-4gamma nuclear receptors in enteroendocrine function and susceptibility to obesity and type 2 diabetes

Ayari, Sami 28 November 2017 (has links)
L’obésité et le diabète de type 2 (DT2) sont des pathologies métaboliques associées à des perturbations de l’homéostasie glucidique et énergétique. Les enterohormones sont des acteurs importants de la regulation des mécanismes perturbés lors de ces pathologies. Parmi ces enterohormones, le GLP-1, sécrété par les cellules entéroendocrines de type L suite à un repas, permet d’amplifier la sécrétion d’insuline par les cellules β-pancréatiques et de diminuer la prise alimentaire. L’objectif de ma thèse a été de caractériser le rôle du récepteur nucléaire HNF-4γ dans l’homéostasie énergétique et la fonction endocrine de l’intestin.A l’aide d’un modèle murin d’invalidation totale et constitutive du facteur de transcription HNF-4γ, notre équipe a mis en évidence que l’absence de HNF-4γ induit une amélioration de la tolérance au glucose grâce à une augmentation du nombre de cellules L et de la quantité plasmatique de GLP-1 en réponse au glucose. L’ensemble de ces données démontre pour la première fois un rôle de HNF-4γ dans l’homéostasie glucidique via une modulation du lignage enteroendocrine spécifique du GLP-1 et suggère que son absence pourrait protéger les souris de l’établissement d’un DT2.Par ailleurs, la perte d’expression de HNF-4γ confère une protection vis-à-vis de la prise de poids et de l’intolérance au glucose normalement induites par six semaines d’un régime riche en lipides et en fructose grâce une perte énergétique accrue dans les fécès essentiellement due à une malabsorption des acides gras.En conclusion, cette étude met en exergue le rôle du récepteur nucléaire intestinal HNF-4γ dans la fonction enteroendocrine et la susceptibilité à l’obésité et au DT2. / Obesity and type 2 diabetes (T2D) are metabolic pathologies associated with glucose and energy homeostasis perturbations. Enterohormones are important players in the regulation of the mechanisms disturbed during these pathologies. Among these enterohormones, GLP-1, secreted by enteroendocrine L cells in response to a meal, potentiates insulin secretion by pancreatic β cells and inhibits food intake. The aim of my thesis was to characterize the role of the nuclear receptor HNF-4γ in the energy homeostasis and the endocrine function of the intestine.By using a total and constitutive HNF-4γ knock-out mouse model, our team has highlighted that the loss of hnf-4γ induces an improved glucose tolerance. This effect is due to an increased GLP-1 cell number and GLP-1 plasma levels in response to glucose. All together these data demonstrate for the first time a role of HNF-4γ in glucose homeostasis through a modulation of the enteroendocrine lineage specific for GLP-1 and suggest that its absence could protect mice from the T2D establishment.The loss of HNF-4γ protects mice from body weight gain and glucose intolerance normally induced by six weeks of a high-fat/high-fructose diet demonstrating its involvement in obesity and T2D. HNF-4γ -/- mice are protected from obesity by a greater energy loss in faeces mainly due to lipid malabsorption. These results demonstrate that HNF-4γ is necessary for the intestinal fatty acids uptake.In conclusion, this study highlights the role of the intestinal nuclear receptor HNF-4γ in enteroendocrine function and susceptibility to obesity and T2D.
7

Characterization of the FTF/HNF-4 Sites Within the 7Alpha- and the 12Alpha-Hydroxylase Promoters Involved in the Bile Acid-Mediated Transcription of their Regulation

Pramanik, Preeti 01 January 2006 (has links)
Bile acids regulate their own synthesis through a feedback regulatory mechanism of mainly two enzymes in the classic pathway, the 7α-hydroxylase and the 12α-hydroxylase. In the early 1990's it was shown that the regulatory responses of 7α-hydroxylase are mediated at the transcriptional level and since then many positive and negative transcription factors that mediate regulatory response have been identified. An important finding was that the transcription factors regulating the expression of 7α- and 12α-hydroxylase genes are nuclear receptors.One of the first nuclear receptors identified to play a role in the transcription of the 7α-hydroxylase gene was HNF-4 since then many nuclear receptors have been identified that are involved in regulating the 7α- and 12α-hydroxylase genes. Among them the most important ones are FTF and HNF-4 which has been shown to play crucial roles in the transcription and regulation by bile acids. In this study we demonstrate the importance of FTF and HNF-4 independent of each other in the transcription and bile acid-mediated regulation of the 7α- and 12α-hydroxylase enzymes by creating promoter mutants that would either bind FTF or HNF- 4. Once the binding studies were established we performed tissue culture experiments to confirm the promoter activity and bile acid-mediated regulation with the respective promoter mutant constructs. The data from this study shows that HNF-4 is important for 7α-hydroxylase promoter activity but is not required and importantly we show that HNF-4 is not a required for the bile acid-mediated regulation of the 7α-hydroxylase. We present data which suggests that FTF is absolutely required for the promoter activity and bile acid-mediated regulation of 7α-hydroxylase. With respect to the 12α-hydroxylases how that both FTF and HNF-4 are absolutely required for promoter activity. In this study we present evidence that since the bile acid responsive elements (BARE) are similar within both the 7α- and 12α-hydroxylase promoters one can be exchanged for the other maintaining both activity and bile acid-mediated regulation.
8

Les Particules d'Exopolymères Transparentes (Transparent Exopolymer Particles, TEP) en milieu pélagique lacustre : relation avec le phytoplancton et rôle dans les réseaux trophiques microbiens

Arnous, Mohamad Bashir 16 November 2010 (has links) (PDF)
Ce travail est une contribution à la connaissance de l'importance des particules de nature polysaccharidique, les TEP (Transparent Exopolymer Particles) ou particules d'Exopolymères Transparentes, en milieu pélagique lacustre.Les différentes études présentées dans ce mémoire se sont essentiellement focalisées sur la distribution de ces particules et leur relation avec le phytoplancton et les autres microorganismes du réseau trophique aquatique en milieu naturel (le lac Pavin, oligo-mésotrophe et le réservoir hypereutrophe de Grangent) et en conditions semi contrôlées(enclos limniques installés sur le lac de Créteil). Les résultats de l'étude printanière au lac Pavin indiquent que la majorité des TEP sont colonisées par les bactéries et que l'intensité de colonisation est fortement liée à la température et diminue avec l'augmentation en taille des particules. La distribution des nanoflagellés hétérotrophes (HNF) est fortement liée à la densité des TEP mais pas à l'intensité de colonisation de ces particules. L'abondance et la surface cumulée de TEP sont significativement plus élevées dans le lac oligo-mésotrophe que dans le réservoir hypereutrophe de Grangent. Les abondances et les concentrations élevées de particules dans le lac Pavin coïncident avec la présence de diatomées de grande taille au printemps et en automne et avec les chlorophycées à la fin de l'été.Dans le réservoir de Grangent les valeurs maximales de TEP coïncident avec le développement de la cyanobactérie Microcystis aeruginosa. Si les TEP augmentent avec la productivité de l'écosystème, la production de ces particules par unité de chlorophylle a dépend de la composition algale et tend à diminuer avec l'augmentation du niveau trophique du milieu. Les résultats issus de la biomanipulation en enclos limniques indiquent que la structure du réseau trophique aquatique (par la présence ou l'absence de poissons planctonophages) influence fortement la distribution,la dynamique et le spectre de taille des TEP. Dans le traitement poisson, l'abondance des TEP, la chlorophylle a et la biomasse des chlorophycées sont fortement corrélées. De par son broutage sur le phytoplancton, le zooplancton a un effet négatif sur les TEP dans le traitement sans poissons mais il contribue sans doute à la formation de TEP e tinfluence le spectre de taille de ces dernières dans ce traitement. Ce travail souligne l'importance des particules de nature polysaccharidique en milieu pélagique lacustre qui doivent être considérées comme une part importante du carbone organique qui transite des producteurs primaires vers les décomposeurs et vers le sédiment.
9

A Drosophila Winged-helix nude (Whn)-like transcription factor with essential functions throughout development

Sugimura, Isamu, Adachi-Yamada, Takashi, Nishi, Yoshimi, Nishida, Yasuyoshi 06 1900 (has links)
No description available.
10

Estudio de las propiedades antiinflamatorias de la heparina no fraccionada en la isquemia cerebral

Cervera Álvarez, Álvaro 24 January 2007 (has links)
INTRODUCCIÓN: La heparina no fraccionada (HNF) se utiliza en el tratamiento del ictus desde varias décadas como fármaco anticoagulante. Los ensayos clínicos aleatorizados no han demostrado eficacia de este tratamiento, por lo que se desaconseja su uso. Sin embargo estos estudios tienen numerosas limitaciones como un excesivo retraso en el inicio del tratamiento, la vía de administración del fármaco y la falta de monitorización. En los últimos años se han descrito numerosas propiedades antiinflamatorias de la HNF que podrían ser beneficiosas en la isquemia cerebral aguda. OBJETIVOS: establecer un modelo animal de tratamiento continuo con HNF que permita mantener una heparinemia dentro de los márgenes terapéuticos deseados y determinar si la HNF administrada de la manera adecuada es neuroprotectora en un modelo de isquemia-reperfusión cerebral focal en rata, estudiar si hay mecanismos antiinflamatorios involucrados en este efecto neuroprotector, analizar marcadores séricos de inflamación en pacientes con ictus para determinar si existe un efecto antiinflamatorio al usar HNF y desarrollar un ensayo clínico aleatorizado comparando la HNF con la aspirina en el tratamiento del ictus isquémico agudo para evaluar la superioridad de este tratamiento. MÉTODOS Y RESULTADOS: Evaluamos la farmacocinética de la HNF en diferentes grupos de rata mediante reactivos cromógenos y encontramos que la dosis que mantenía una heparinemia constante de 0.3 a 0.6 U/mL fue un bolus de 200 U/kg seguido de una perfusión intraperitoneal de 70 U/kg/h. Mediante la técnica de oclusión endoluminal de la arteria cerebral media determinamos que la HNF iniciada a las 3 horas de la isquemia reducía el volumen de infarto cerebral en un 46% respecto al grupo control. Este efecto neuroprotector se acompañó de una elevación de los niveles plasmáticos de IL-10, de una mayor expresión de hemooxigenasa-1, y de una menor expresión de VCAM-1. En pacientes con isquemia cerebral agudo, encontramos una mayor respuesta de fase aguda (leucocitos totales, porcentaje de polimorfonucleares y velocidad de sedimentación globular) en los tratados con aspirina que en los que recibieron HNF. La reacción de fase aguda fue menor que presentaban una recuperación completa al alta. Además se demostró una asociación positiva entre el uso de HNF y la recuperación completa, sobre todo en el ictus no lacunar. En otro estudio el aumento de VCAM-1 sérica a las 48 horas se asoció de forma independiente con una peor recuperación a los 6 meses. Los niveles de VCAM-1 sérica fueron 1.24 veces mayores en los pacientes tratados con aspirina. Por último, realizamos un ensayo aleatorizado, el estudio RAPID, comparando la eficacia de la aspirina y de la HNF en el ictus isquémico no lacunar de menos de 12 horas de evolución. El estudio se cerró prematuramente con 67 pacientes incluidos. La HNF demostró un perfil de seguridad igual al de la aspirina. CONCLUSIONES: La HNF administrado de forma adecuada es neuroprotectora en el modelo de isquemia-reperfusión cerebral focal de rata, ya que reduce en un 46% el volumen de infarto. La acción neuroprotectora de la HNF está mediada por mecanismos antiinflamatorios, como el incremento de la IL-10 plasmática, el aumento de la expresión de la hemooxigenasa-1 y la inhibición de la inducción de la VCAM-1. En pacientes con ictus tratados con HNF se observa una menor respuesta de fase aguda y niveles séricos más bajos de VCAM-1. Esta disminución de marcadores inflamatorios se asoció con una mejor recuperación funcional.La medicina basada en la evidencia no tiene, en estos momentos, datos suficientes para evaluar la eficacia y seguridad del tratamiento con HNF en las primeras 12 horas tras un ictus isquémico no lacunar. No obstante, el estudio RAPID aporta que el perfil de seguridad de la HNF puede ser similar al de la aspirina y una mayor eficacia en la prevención de recurrencias tempranas.

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