• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 88
  • 16
  • 6
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 128
  • 128
  • 18
  • 12
  • 12
  • 11
  • 10
  • 9
  • 9
  • 9
  • 8
  • 8
  • 7
  • 7
  • 7
  • 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.
101

Caracterização de célula progenitora hepática no cultivo celular de fígado de feto canino /

Tavares, Mariana Riboli. January 2016 (has links)
Orientador: Gilson Hélio Tonillo / Coorientador: Joaquim Mansano Garcia / Coorientador: Annelise Carla Camples / Banca: Maricy Apparício Ferreira / Banca: Fabiana Ferreira de Souza / Resumo: Com a descoberta das células-tronco abriu-se um leque de possibilidades nas pesquisas de nichos destas em diferentes órgãos e também no estudo de doenças e regeneração tecidual. O fígado vem sendo alvo de muitos estudos já que as doenças crônicas deste órgão tem como resolução um transplante, o que é caro e há poucos doadores. O fígado é composto, principalmente, por hepatócitos, no entanto, seu cultivo e mantença in vitro são difíceis. Assim, uma alternativa é a manutenção das células progenitoras hepáticas. Elas são conhecidas em camundongos, humanos, mas, pouco mencionadas em cães. Esse trabalho objetivou mostrar a existência das células progenitoras hepáticas no cultivo celular de fígado fetal de cães por imunocitoquímica e citometria de fluxo a fim de saber se este nicho celular existe no cultivo e se é possível num futuro próximo a separação desta linhagem nesta espécie. Foram utilizados para a realização do trabalho 10 fetos sendo que destes foi possível o aproveitamento em sete animais. Foi realizado no trabalho isolamento, cultivo de células hepáticas, criopreservação, curva de crescimento celular, imnocitoquímica e citometria de fluxo. A cultura celular durou sete passagens, com dobramento populacional de 31,7 horas, na imunocitoquímica as células foram marcadas positivamente para os seguintes marcadores: EpCAM, NCAM, Nestina e Thy-1.Na citometria de fluxo foi possível realizar a dupla marcação das células com os maracadores EpCam e NCAM que resultaram em 0... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: With the discovery of stem cells has opened up a range of possibilities in niche research these in different organs and also in the study of diseases and tissue regeneration the liver has been the subject of many studies since chronic diseases of this organ has the resolution a transplant, which is expensive and there are few donors. The liver consists mainly of hepatocytes; however, its cultivation and maintenance in vitro are difficult. Thus, an alternative is to maintain the hepatic progenitor cells. They are known in mice, humans, but rarely mentioned in dogs. This study aimed to show the existence of hepatic progenitor cells in cell culture fetal liver of dogs by immunocytochemistry and flow cytometry in order to know if this cell niche exists in the cultivation and whether it is possible in the near future the separation of this lineage in this species. They were used to carry out the work 10 fetuses and of these it was possible to use in seven animals. Work was carried out in isolation, cultivation of liver cells, cryopreservation, cell growth curve, immunocytochemistry and flow cytometry. The cell culture lasted seven passes, doubling time in 31.7 hours, in immunocytochemistry cells were positively stained for the following markers: EpCAM, NCAM, Nestin and Thy-1. In flow cytometry it was possible to double staining of cells with EpCam markers and NCAM which resulted in 0.5 % ± 0.173 of the total of the cells analyzed. Concludes that the purpose of the desir... (Complete abstract click electronic access below) / Mestre
102

Estudo do processo de esferolização de partículas vítreas visando à aplicação em radioterapia interna seletiva / Study of the spheroidization process of glass particles for selective internal radiotherapy

BARROS FILHO, ERALDO C. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:34:33Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:00:13Z (GMT). No. of bitstreams: 0 / A radioterapia interna seletiva é uma alternativa para o tratamento do carcinoma hepatocelular. Nesta terapia, microesferas de vidro contendo radionuclídeos são introduzidas no fígado por meio de um cateter acoplado à artéria hepática dos pacientes e são retidas em regiões microvasculares que alimentam o tecido lesado. Estas micropartículas aniquilam as células cancerosas por meio da radiação β-, e, quando simultaneamente emitem raios γ, podem também ser utilizadas para imageamento do tumor. As partículas vítreas devem possuir o formato esférico para não provocar hemorragias desnecessárias e também diâmetro adequado para otimizar o bloqueio efetivo da alimentação do tumor e evitar a migração para outros órgãos que poderia causar doses em tecidos sadios. Além disso, devem ter durabilidade química adequada e não serem citotóxicas. A distribuição do tamanho de microesferas depende de muitos parâmetros como a razão de aspecto, formação de aglomerados, e temperatura de processamento. No presente trabalho é apresentado um estudo do processo de esferolização de partículas vítreas caracterizadas por difração de raios X, espectrometria de fluorescência de raios X por energia dispersiva, área superficial específica, teste de citotoxicidade e calorimetria exploratória diferencial. Foram determinadas a taxa de dissolução do vidro em água destilada a 90oC (DR~10-8g.cm-2.min-1), densidade (2,79g.cm-3), viscosidade e granulometria. A morfologia das microesferas foi avaliada por microscopia eletrônica de varredura antes e após os testes de dissolução em SBF e irradiação por feixe de nêutrons. Propõem-se o peneiramento para seleção das microesferas apropriadas para o tratamento pretendido e testes in vivo visando a sua aplicação em radioterapia interna seletiva. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
103

Expressão de enzimas envolvidas na produção de triacilglicerol em tecidos adiposo e hepático isolados de ratos normo e hiperlipidêmicos / Expression of enzymes involved in the production of triacylglycerol in adipose and liver isolated tissue from normo and hyperlipidemic rats

Bellenzani, Marcela Palomo Pieroni, 1984- 20 August 2018 (has links)
Orientador: Dora Maria Grassi Kassisse / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-20T14:23:50Z (GMT). No. of bitstreams: 1 Bellenzani_MarcelaPalomoPieroni_M.pdf: 6472856 bytes, checksum: e473a96a17b23ee1d9a456d9ac7a4602 (MD5) Previous issue date: 2012 / Resumo: A pandemia da obesidade é evidente no início do século XXI. O fator desencadeante mais relevante é a alimentação hipercalórica associada ao sedentarismo. Modelos de estudo em ratos para investigar as etapas que precedem o desenvolvimento desta doença são fundamentais para propor terapias de prevenção. No modelo de indução da dislipidemia pela dieta por quatro semanas, os ratos apresentam hipercolesterolemia, hipertrigliceridemia e hiperinsulinemia e com seis semanas de administração da dieta observa-se um aumento no peso dos panículos adiposos da região epididimal e peri-renal e sem alteração no depósito da região mesentérica. Assim sendo, objetivamos, nesta tese, analisar as vias metabólicas envolvidas no processo de metabolização da glicose e triacilgliceróis nos tecidos adiposo branco e hepático em ratos hiperlipidêmicos e para tal estudamos as vias lipogênica, lipolítica e neoglicogênica, pela quantificação da expressão gênica das enzimas chaves envolvidas nestes processos. A dislipidemia foi induzida pelo oferecimento de dieta hiperlipídica (grupo dieta, D) ao longo de quatro semanas a ratos jovens e a instalação do quadro foi verificada pelas análises plasmáticas ao final do tratamento e após jejum de 16h. Amostras de tecidos hepático e adiposo foram coletadas para análise histológica e quantificação da expressão gênica sendo estas analisadas por qRT-PCR. Observou-se que ratos que ingerem dieta hiperlipídica (+129+10,13 g) ganham peso de forma semelhante aos ratos controle (C: +148+8,8 g) mesmo ingerindo quantidade significativamente menor de dieta (C: 20,8+0,62 g vs D: 14,87+0,66 g). As análises histológicas ilustram aumento no teor de depósitos de lipídeos no tecido hepático. A expressão gênica no tecido hepático de ratos dieta foi aumentada significativamente para as enzimas lipoproteína lipase, piruvato desidrogenase quinase 4 e fosfofrutoquinase 1 e diminuição significativa na expressão de glicose 6-fosfatase sem alteração na quantificação da expressão de acetil-CoA carboxilase alpha, gliceroquinase, piruvato desidrogenase fosfatase 2. Em relação ao tecido adiposo observamos que a expressão das enzimas acetil-CoA carboxilase e piruvato desidrogenase fosfatase 2 não foi significativamente alterada em nenhum dos depósitos adiposos. A lipase hormônio-sensível não apresentou alterações no tecido adiposo epididimal, porém teve sua expressão significativamente aumentada nos tecidos mesentérico e peri-renal. A expressão da lipoproteína lipase por sua vez, não se alterou no panículo adiposo epididimal nem no panículo adiposo mesentérico estando diminuída no panículo adiposo peri-renal. E por fim, a piruvato desidrogenase quinase 4 também não apresentou alterações nos depósitos epididimal e mesentérico porém no peri-renal sua expressão encontrou-se aumentada. Estes resultados, em conjunto, indicam que a dieta administrada por 4 semanas, mesmo não apresentando todas as alterações observadas com 6 semanas, pode ser útil para os estudos iniciais do quadro de dislipidemia que antecedem as disfunções metabólicas / Abstract: The pandemic of obesity is evident in the twenty-first century. The most important and triggering factor is the high-calorie diet associated with physical inactivity. Study models in rats to investigate the steps that precede the development of this disease are essential to propose preventive therapies. In the model of induction of dyslipidemia by diet for four weeks, the mice exhibit hypercholesterolemia, hypertriglyceridemia, and hyperinsulinemia and there is an increase in weight of the panniculus region of epididymal and peri-renal depot and no change in the mesenteric region. Therefore, we aimed to analyze the metabolic pathways involved in the metabolism of glucose and triglycerides in white adipose tissue, and liver in hyperlipidemic rats and to study the ways that lipogenic, lipolytic and glyconeogenic for the quantification of gene expression of key enzymes involved in these processes. Dyslipidemia was induced by offering high-fat diet (diet group, D) over four weeks to young rats and onset of condition was verified by analysis at the end of the plasma treatment and after fasting for 16 hours. Samples of liver and adipose tissue were collected for histological analysis and quantification of gene expression and these were analyzed by qRT-PCR. It was observed that mice eat high-fat diet (+129 +10.13 g) gain weight similarly to control rats (C: +8.8 +148 g) even eating significantly less diet (C: 20.8 +0.62 g vs D: 14.87 +0.66 g). Histological analysis illustrate the content of lipid deposits in liver tissue. Gene expression in liver tissue of rats diet was significantly increased for the enzymes lipoprotein lipase, pyruvate dehydrogenase kinase 4 and 1 and Phosphofructokinase significant decrease in the expression of glucose 6-phosphatase no change in the quantification of the expression of acetyl-CoA carboxylase alpha, Gliceroquinase, pyruvate dehydrogenase phosphatase 2. In relation to the adipose tissue we observed that the expression of the enzyme acetyl-CoA carboxylase and pyruvate dehydrogenase phosphatase 2 was not significantly altered in any of the fatty deposits. The hormone-sensitive lipase showed no changes in epididymal adipose tissue but its expression was significantly increased in mesenteric tissue and peri-renal. Lipoprotein lipase, in turn, did not change in the mesenteric or epididymal being reduced in the peri-renal. And finally, the pyruvate dehydrogenase kinase 4 also showed no changes in epididymal and mesenteric but the peri-renal expression is increased. These results, together, indicate that the diet for 4 weeks, even not showing all changes observed within 6 weeks, can be useful for the initial studies of hyperlipidemia that precede the metabolic dysfunctions / Mestrado / Fisiologia / Mestre em Biologia Funcional e Molecular
104

Phosphatidylcholine biosynthesis and lipoprotein secretion in rat hepatocytes

Yao, Zemin January 1988 (has links)
Young male rats fed a choline-deficient diet for three days accumulated triacylglycerol (TG) in the liver, and had reduced very low density lipoprotein (VLDL), but not high density lipoprotein (HDL), levels in the plasma. Cultured hepatocytes obtained from these rats were used as a model system to investigate how choline deficiency affected hepatic lipogenesis, apolipoprotein synthesis and lipoprotein secretion. When the cells were cultured in a medium free of choline and methionine, the secretion of TG and phosphatidylcholine (PC) was impaired. Supplementation of choline, methionine or lysophosphatidylcholine (lysoPC) to the culture medium increased the secretion of these lipids to normal levels, and stimulated PC biosynthesis. Fractionation of the secreted lipoproteins by ultracentrifugation revealed that the reduced secretion of TG and PC from choline-deficient cells was mainly due to impaired secretion of VLDL. The secretion of HDL and lipid-free proteins (for example albumin), however, was not affected by choline and methionine deficiency. Supplementation of betaine and homocysteine also stimulated PC biosynthesis and enhanced hepatic VLDL secretion. However, supplementation of ethanolamine, N-monomethylethanol-amine or N, N-dimethylethanolamine did not correct the impaired VLDL secretion from the hepatocytes, although an active synthesis of phosphatidylmonomethyl-ethanolamine (PMME) and phosphatidyldimethylethanolamine was observed. Choline deficiency had no effect on the rate of incorporation of [³H]leucine into cellular apolipoprotein B, E and C or on the rate of disappearance of radioactivity from the labeled apolipoproteins. These results suggest that biosynthesis of PC is specifically required for hepatic VLDL (but not HDL) secretion, and any one of the three synthetic pathways, the CDP-choline pathway, methylation of phospha-tidylethanolamine (PE) or reacylation of lysoPC, is sufficient to provide the required PC. The total activity of cytidylyltransferase in liver was unchanged in choline deficiency. However, choline deficiency caused an abnormal distribution of cytidylyltransferase activity between rat liver cytosol and microsomes (mainly endoplasmic reticulum), a decrease in the cytosolic enzyme activity and an increase in the microsomal enzyme activity. In cultured hepatocytes from the choline-deficient rat, the abnormally distributed cytidylyltransferase activity could be rapidly reversed by the addition of choline, but not lysoPC, to the culture medium. The stimulated microsomal activity of cytidylyltransferase during choline deficiency might be a mechanism whereby the cells could more effectively utilize phosphocholine to maintain a normal CDP-choline level in the choline-deficient liver. Rat liver PE N-methyltransferase catalyzes all three transmethylation reactions in the conversion of PE to PC. The in vitro activity of PE N-methyltransferase was increased in choline-deficient livers using endogenous PE as the methyl group acceptor. However, no significant changes were observed in the enzyme activity when exogenous PMME was used as the methyl group acceptor. Addition of methionine to the cultured hepatocytes obtained from choline-deficient rats resulted in a concomitant reduction in cellular PE levels and the specific activity of PE-dependent methyltransferase. However, the specific activity of PMME-dependent methyltransferase was not significantly altered upon the addition of methionine. No change in PE N-methyltransferase activity was observed in the cultured hepatocytes supplemented with choline. Immunoblotting of PE N-methyltransferase, in crude liver microsomes and in membrane fractions of cultured hepatocytes, revealed that the enzyme mass was not altered by choline and methionine deficiency. Thus, hepatic PE N-methyltransferase is preserved in choline deficiency, and its activity is probably dependent on the availability of metabolic substrates (i.e. methionine and PE). / Medicine, Faculty of / Biochemistry and Molecular Biology, Department of / Graduate
105

Interaction of DEHA with mammalian cells

McGlynn, Andrea. January 2007 (has links)
No description available.
106

Metabolism of supplemental iron by hepatic parenchymal and sinusoidal cells of the neonatal pig

Caperna, Thomas J. January 1986 (has links)
Methods were developed to isolate and culture the predominant cell types from porcine liver to investigate hepatic accumulation, distribution and intracellular metabolism of supplemental iron. Hepatocytes were prepared from collagenase perfused livers by differential centrifugation, while Kupffer cells and endothelial cells were isolated by centrifugal elutriation. One day old piglets were injected with iron-dextran (Fe-dextran) and the concentration of accumulated iron was determined in all three cell types 1, 5, and 10 days later. The concentration of iron increased markedly in all three cell types when compared to cells isolated from untreated piglets (Kupffer cells > endothelial cells >> hepatocytes). Accumulated iron was subsequently mobilized from all three cell types. The role of ferritin in metabolism and storage of accumulated iron was investigated. An antiserum was prepared against porcine liver ferritin and the quantity of cellular ferritin was measured by immunoelectrophoresis. The amount of cellular iron associated with ferritin was assessed by ion exchange chromatography. All three types of liver cells accumulated ferritin in response to Fe-dextran treatment. Higher concentrations of ferritin-iron and ferritin-protein were present in Kupffer and endothelial cells than in hepatocytes at all times after iron treatment. However, at 1 day after treatment 48% of the total iron within hepatocytes was associated with ferritin; ferritin-iron accounted for only 10% of total cell iron by day 10. In contrast, ferritin-iron represented only approximately 9% of the total iron in sinusoidal cells throughout the study period. The possibility that accumulation of Fe-dextran enhanced peroxidation of membrane lipids was evaluated. Lipids extracted from heart and liver of iron-treated piglets contained increased levels of conjugated dienes. High levels of conjugated dienes were present in endothelial cells and hepatocytes 1 day after treatment and only in endothelial cells by day 5. Although Kupffer cells accumulated substantial quantities of Fe-dextran, conjugated dienes were not detectable. These studies indicate that treatment of piglets with Fe-dextran may selectively impair function of hepatic endothelial cells and perhaps hepatocytes, and define new criteria for evaluating compounds that are used for iron supplementation. / Ph. D. / incomplete_metadata
107

MicroRNA profiling of human hepatocytes induced by HBx in hepatocarcinogenesis.

January 2009 (has links)
Yip, Wing Kit. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 100-119). / Abstract also in Chinese. / Abstract (English version) --- p.i / Abstract (Chinese version) --- p.iii / Acknowledgments --- p.v / Table of Contents --- p.vii / List of Tables --- p.x / List of Figures --- p.xi / List of Abbreviations --- p.xiii / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Hepatocellular Carcinoma --- p.1 / Chapter 1.1.1 --- Epidermiology --- p.1 / Chapter 1.1.2 --- Etiology --- p.1 / Chapter 1.2 --- Hepatitis B Virus --- p.3 / Chapter 1.2.1 --- The Epidermiology of Hepatitis B Virus Infection --- p.3 / Chapter 1.2.2 --- The Morphology and Genome of Hepatitis B Virus --- p.4 / Chapter 1.2.3 --- HBV Genotypes and Their Significance --- p.8 / Chapter 1.3 --- Hepatitis B Virus X Protein --- p.9 / Chapter 1.3.1 --- HBx Alters Various Signal Transduction Pathways --- p.10 / Chapter 1.3.2 --- HBx Interacts with Various Transcription Factors and Co-activators --- p.12 / Chapter 1.3.3 --- HBx Induces Epigenetic Alterations --- p.14 / Chapter 1.3.4 --- Identification of COOH-terminal Truncated HBx in Liver Tumors --- p.15 / Chapter 1.4 --- MicroRNAs --- p.17 / Chapter 1.4.1 --- Transcriptional Regulation and Biogenesis of MicroRNAs --- p.18 / Chapter 1.4.2 --- MicroRNAs and Cancer --- p.21 / Chapter 1.4.3 --- MicroRNAs and HCC --- p.25 / Chapter 1.5 --- Hypothesis and Aims of the Study --- p.29 / Chapter CHAPTER 2 --- MATERIALS and METHODS --- p.30 / Chapter 2.1 --- Patients --- p.30 / Chapter 2.2 --- Cell Lines --- p.30 / Chapter 2.3 --- Cloning of Various HBx Constructs --- p.32 / Chapter 2.3.1 --- PCR Amplification of HBx Fragments --- p.32 / Chapter 2.3.2 --- Cloning of HBx Fragments into TA-vectos --- p.33 / Chapter 2.3.3 --- Heat Shock Transformation --- p.33 / Chapter 2.3.4 --- Sub-cloning of HBx Fragments into Lentiviral Vectors --- p.34 / Chapter 2.4 --- Generation of Lentivirus --- p.37 / Chapter 2.4.1 --- Lentivirus Infection --- p.37 / Chapter 2.5 --- RNA Extraction --- p.38 / Chapter 2.6 --- Western Blot Analysis --- p.39 / Chapter 2.7 --- MiRNA Microarray --- p.40 / Chapter 2.7.1 --- Cyanine3-pCp Labeling of RNA Samples --- p.40 / Chapter 2.7.2 --- Sample Hybridization --- p.41 / Chapter 2.7.3 --- Microarray Wash --- p.41 / Chapter 2.7.4 --- Array Slide Scanning and Processing --- p.41 / Chapter 2.8 --- Detection of HBx Gene Deletion by PCR --- p.43 / Chapter 2.9 --- Immunohistochemistry --- p.44 / Chapter 2.10 --- Quantitative Real-time PCR --- p.45 / Chapter 2.11 --- Proliferation Assay --- p.47 / Chapter 2.12 --- Cell Cycle Analysis --- p.48 / Chapter 2.13 --- Annexin V Apoptosis Assay --- p.49 / Chapter 2.14 --- Colony Formation Assay --- p.50 / Chapter 2.15 --- Statistical Analysis --- p.51 / Chapter CHAPTER 3 --- RESULTS --- p.52 / Chapter 3.1 --- Detection of Full-length and COOH-terminal Truncated HBx in HCC Tissues --- p.52 / Chapter 3.2 --- Confirmation of HBx Expression in HCC Tissues --- p.55 / Chapter 3.3 --- Comparison of HBx from Different HBV Genotypes for Study --- p.61 / Chapter 3.4 --- Functional Characterization of COOH-tterminal Truncated HBx --- p.64 / Chapter 3.4.1 --- Selection of COOH-terminal Truncated HBx --- p.64 / Chapter 3.4.2 --- Generation of Various HBx-expressing Hepatocyte Cell Lines --- p.66 / Chapter 3.4.3 --- Effect of Full-length and COOH-terminal Truncated HBx on Cell Proliferation --- p.69 / Chapter 3.4.4 --- Effect of Full-length and COOH-terminal Truncated HBx Cell Cycle --- p.34 / Chapter 3.4.5 --- Effect of Full-length and COOH-terminal Truncated HBx on Apoptosis --- p.45 / Chapter 3.5 --- MicroRNA Profiling of Various HBx-expressing Hepatocyte Cell Lines --- p.76 / Chapter 3.5.1 --- Identification of Deregulated MicroRNAs by Microarray --- p.76 / Chapter 3.5.2 --- Validation of Deregulated MicroRNAs by Real-time PCR Analysis --- p.80 / Chapter 3.5.3 --- Confirmation of Deregulated MiRNAs in HCC and Adjacent Non-tumor Tissues --- p.84 / Chapter 3.5.4 --- Potential Downstream Targets of the HBx-deregulated MiRNAs --- p.87 / Chapter CHAPTER 4 --- DISCUSSION --- p.91 / Chapter 4.1 --- The Impact of COOH-terminal Truncated HBx in HCC --- p.91 / Chapter 4.2 --- The Biological Significance of COOH-terminal Truncated HBx Induced MiRNAs --- p.94 / Chapter 4.3 --- Limitations of the Present Study --- p.97 / Chapter 4.4 --- Future Studies --- p.98 / Chapter CHAPTER 5 --- CONCLUSION --- p.99 / REFERENCES --- p.100
108

The study of glucose-6-phosphate dehydrogenase (G6PD) gene regulation in HepG2 cells by glucose induction and the study of G6PD mRNA localization by fluorescent in situ hybridization (FISH)

Griffith, Brian Nelson. January 2002 (has links)
Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains viii, 100 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 80-96).
109

Pro- and anti-apoptotic roles of map kinase signaling in liver exposed to alcohol

Lee, Youn Ju, January 2003 (has links)
Thesis (Ph. D.)--University of Missouri--Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 172-205). Also available on the Internet.
110

Insulin secretion dynamics of recombinant hepatic and intestinal cells

Gulino, Angela Marie 31 March 2008 (has links)
Hepatic and intestinal endocrine cells are potentially helpful targets for recombinant insulin expression. As the two cell types exhibit different secretion kinetics,it has been hypothesized that a combination of the two would better approximate insulin secretion kinetics from normal, functioning beta-cells than either cell type alone. This hypothesis was tested using two hepatic cell lines transiently transduced with one of three adenoviruses for insulin expression along with a stably transfected recombinant intestinal L cell line. The insulin secretion kinetics were analyzed for both the hepatic and intestinal cells to determine the potential of combining them to reproduce the insulin secretion kinetics of a normal, functioning beta-cell. It was observed that the two recombinant hepatic cell lines secreted insulin in a more sustained manner exhibiting slower release kinetics. They also exhibited an increase in insulin secretion when stimulated by the cocktail of nutrient secretagogues (glucose and meat hydrolysate) versus stimulating with only glucose. The cells transduced with the adenovirus containing an additional cytomegalovirus (CMV) promoter and green fluorescent protein (GFP) exhibited the highest insulin secretion after stimulation, whereas the cells transduced with an adenovirus encoding for destabilized preproinsulin mRNA exhibited the lowest secretion rates. The recombinant intestinal cell line (GLUTag-INS) secreted insulin with rapid kinetics upon stimulation, apparently due to the presence of secretory granules containing pre-synthesized insulin. The experiments demonstrated that the cells stimulated with medium containing only meat hydrolysate exhibited a significantly higher insulin secretion relative to secretagogue-free controls. The insulin secretion was not further enhanced when meat hydrolysate was combined with glucose.

Page generated in 0.0561 seconds