Дисертації з теми "Intestine, Small"
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1
Masjedi, Mohsen. "Physiological inflammation of the small intestine during weaning in the rat /." Title page, table of contents and summary only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phm3973.pdf.
2
Dimas, Sophie Francis. "The response in the rat small intestine to infections of 5 and 50 cysticercoids of H. diminuta a morphometric study /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0015/MQ56172.pdf.
3
Gray, Allison J. "Saccharomyces boulardii and the small intestine." Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282154.
4
Hastewell, J. G. "Pyrimidine transport in rat small intestine." Thesis, University of York, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373286.
5
Dosh, Rasha. "Developing models of the small intestine." Thesis, Sheffield Hallam University, 2018. http://shura.shu.ac.uk/24027/.
Анотація:
Inflammatory bowel disease (IBD) is a chronic autoimmune disease characterised by inflammation of the gastrointestinal tract. The pathogenesis of IBD is not fully understood and curative therapies are lacking. Consequently, development of robust intestine models, representative of the pathogenesis of IBD remains an unmet need. Thus, the overall aims of the studies presented in this thesis were to develop a number of models of small intestine including: genetically engineered murine model, epithelial cell culture models, and an intestinal stem cell organoid model which could reflect or be used to study the pathogenesis of IBD. Interleukin 1 (IL-1) is an important mediator of inflammation and tissue damage in IBD. The balance between IL-1 and IL-1Ra as a natural inhibitor plays a vital role in a variety of diseases. Here, this thesis investigated whether changes seen during IBD could be induced spontaneously by the removal of IL-1Ra in mice that lack a functional IL-1rn gene. Data presented from this thesis highlighted the importance of IL-1 in the pathogenesis of inflammatory bowel disease. In addition, the potential of L-pNIPAM hydrogel scaffolds, which were developed by the research team at Sheffield Hallam University, was utilised to develop long-term 3D co-cultures of layered Caco-2 and HT29-MTX cells under conditions representative of inflammation by treatment with IL-1β, TNFα, and hypoxia (1% O2) for 1 week was investigated. In vitro cell culture studies in this thesis have demonstrated that L-pNIPAM hydrogel supported long-term 3D co-culture model and stimulation with factors seen during inflammation recapitulated features of IBD. Finally, the potential of L-pNIPAM hydrogel scaffolds to develop 3D intestinal stem cell organoid model was investigated. The in vitro study demonstrated the ability of L-pNIPAM hydrogel as scaffold to support organoid formation and cell differentiation in vitro from small intestinal crypts and Lgr5+ stem cells isolated from mice.
6
Dabareiner, Robin Marie. "Evaluation of the microcirculation of the equine small intestine following intramural distention and reperfusion." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-09052009-040410/.
7
Lubin, Alexandre. "Preservation of the small intestine for transplantation." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23915.
Анотація:
Transplantation of the small intestine is technically feasible, and the only potentially curative method for patients with short gut syndrome. However this procedure is still infrequent, partially because there is still no reliable method to preserve the small bowel (SB) for a reasonable period of time between removal from the donor and transplantation. In search of a suitable medium for SB preservation, we evaluated different solutions which have been successfully used for preservation of other human organs (Eurocollins (EC), University of Wisconsin (UW) and lactated Ringer's (LR)) and tried to improve their effectiveness by adding superoxide dismutase and catalase or verapamil. The adequacy of preservation was assessed by evaluating the physiological properties of the intestine in vitro, using either the rat syngeneic model of intestinal transplantation, or human intestine obtained from organ donors.LR is a simple, inexpensive and universally available solution, and when supplemented with verapamil, it was as effective as the more complex EC and UW as a protectant against ischemic damage during cold storage of rat ileum. Studies on human intestine validated the rat as an experimental model since the relative effectiveness of the different solutions was similar, however, the human bowel appeared more vulnerable to ischemic and mechanical damage. The results indicate that creation of an effective preservation solution for the small intestine should be possible through appropriate modification of currently available preparations.
8
Serrano, Maria. "Immature intraepithelial lymphocytes in the small intestine." Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.499939.
9
Al-Sawan, Shorooq M. Z. "Phosphate absorption in the rat small intestine." Thesis, University of Newcastle Upon Tyne, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287463.
10
Wallis, Jennifer Lesley. "Glucose transport in the aged small intestine." Thesis, University of Newcastle Upon Tyne, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287145.
11
Fonseca, Monica Rosalia Jaime. "An engineering understanding of the small intestine." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3522/.
Анотація:
The main objective of this research was to understand phenomena occurring during food digestion and nutrients absorption in the small intestine from an engineering perspective. Intestinal flow and mixing processes were simulated using a dynamic in vitro Small Intestine Model (SIM). Of particular interest was to study the effect that mixing and food formulation has on glucose absorption and starch hydrolysis. Results showed the effect of segmentation motion on nutrient delivery to the intestinal wall as a consequence of changes in the mass transfer coefficient. This is most likely due to the increased mixing in the SIM. Experiments of starch digestion with and without the presence of guar gum have shown that viscous fibres reduce the rate of starch digestion and glucose absorption by impairing mixing and reducing diffusion within the fluid. Similarly, use of particulate systems demonstrated a significant effect on the delivery rates. Flow visualization techniques used for studying flow paths in the SIM showed that this in vitro model reproduces the characteristic flow events and mixing found in the small intestine in vivo. This research provides insights into the role of mixing on enhancing mass transfer on the course of digestion-absorption processes and also the action of viscous polysaccharides on the delay of glucose absorption in the small intestine. The end findings resulted in a better understanding of the factors which control the development of new functional food that could be applied both in academia and industry.
12
Gagnon, Jeffrey. "The proprotein convertases in the murine small intestine." Thesis, University of Ottawa (Canada), 2008. http://hdl.handle.net/10393/28225.
Анотація:
The small intestine (SI) is a major endocrine organ with over 40 precursor hormones produced and proteolytically matured into active peptide hormones which signal throughout the body including the pancreas and CNS. One group of enzymes believed to be responsible for this maturation is the family of protein convertases (PCSKs). Using double immunofluorescent microscopy, the spatial localization of PCSK1, 2 and 3 in each region of the SI and colocalization with potential intestinal substrates was examined in mice. A unique regional expression pattern was observed for each of the PCSKs and several hormones examined exhibited high levels of colocalization. Next the gastrointestinal physiology of the PCSK2 knock out (KO) mouse was examined and correlated with the circulating levels of hormones known to mediate these functions. KO animals consume less food immediately after refeeding and have delayed intestinal transit. Several of the hormones responsible for feeding and intestinal motility were modulated in the PCSK KO animals. These studies suggest that the PCSK1 2 and 3 are present in the SI and required for normal functionality.
13
Karim, A. R. "Transport of lithium ion across rodent small intestine." Thesis, University of Wolverhampton, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356360.
14
Sykes, Andrew Philip. "Peptide transport and hydrolysis in rat small intestine." Thesis, University of York, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428416.
15
Combrinck, Marc Irwin. "Apolipoprotein biosynthesis and turnover in mammalian small intestine." Doctoral thesis, University of Cape Town, 1994. http://hdl.handle.net/11427/27140.
Анотація:
The mammalian small intestine is a major site (second in total activity only to the liver) for the synthesis and secretion of plasma apolipoproteins, and contributes significantly to overall whole-body lipid dynamics. A prominent feature of the small intestine is its exposure to periodic loads of meals often containing dramatically varying amounts or types of food components, including lipids such as tri-acylglycerols, cholesterol and cholesteryl esters. Since the trans-epithelial transport of most of these latter materials requires the elaboration of particles partially covered by apolipoproteins, the regulation of the biosynthesis or, more correctly, the availability of these proteins is an important and as yet little-understood problem. Previous studies have been conducted on systems which, for one or the other reason, have not permitted the following questions to be satisfactorily or coherently answered: Does the ingestion of fat-containing meals, either acutely or chronically, increase the rate of biosynthesis of intestinal apolipoproteins such as apo B-48, and is this the principal method of matching the "demand" with the supply of this "packaging material" needed for fat transport across the intestinal epithelial cells? Alternatively, does the maintenance of a large steady-state intracellular pool in the face of variations in intracellular apolipoprotein degradation, controlled by acute or chronic lipid ingestion, produce the required "match" between supply and demand for these proteins (as has recently been suggested in studies on liver cells)? An in vitro system was therefore devised whereby sheets of intestinal epithelial cells (enterocytes) were freshly isolated from the jejuna of adult male Syrian golden hamsters and incubated for several hours in a medium supporting steady-state protein synthesis, in a manner which was assumed to be similar to the activity just before the killing of the donor animals. (Hamsters appear on various grounds to be a better small-animal model of human lipoprotein metabolism than the more commonly studied rats). The isolated epithelial cell sheets produced primary apolipoprotein products that could be extracted from the cells or detected in the incubation media, free from the subsequent modifications that they are known to undergo in vivo. Hamsters maintained on a low-fat chow were either studied as such or subjected to a variety of dietary treatments designed to maximize (over short or long time periods) intracellular apolipoprotein requirements for the "packaging" of tri-acylglycerol-rich lipoproteins, especially chylomicrons: acute bolus administration of lipid into the gut; overnight feeding of fat-enriched food; and chronic (six week) fat feeding. Using specific antisera and immuno-precipitation techniques, apo B-48 and two other principal intestinal apolipoproteins were shown to be synthesized in the steady state by intestinal cell sheets derived from control animals and from those subjected to acute or chronic fat-containing diets. Secretion took place, however, only when prior fat exposure of the donor intestines had occurred. Pulse-chase labelling was used to compare the rates of apolipoprotein synthesis, degradation and secretion in the same cell sheet preparations. The rates of apolipoprotein B-48 synthesis did not vary significantly under conditions of low or high trans-epithelial lipid flux, supporting findings derived from in vivo experimental systems. In contrast with data from other systems, however, the biosynthesis of apolipoprotein A-IV was not reproducibly increased on fat challenge. The rates of apo B-48 degradation varied significantly and were markedly reduced under conditions of fat feeding. The experiments permit a choice between the two alternatives mentioned above: Ingestion of fatty foods, either acutely or over long periods of time, does not increase the rates of biosynthesis of apolipoproteins such as apo B-48; but variations in the rate of intracellular degradation of this and probably other apolipoproteins allows the intestinal cells to match their requirements for lipid-transporting molecules to the demands of any given situation, relying in each case on a large steady-state intracellular pool maintained by "constitutive" biosynthesis. Importantly, there seems also to be a specific, possibly related effect of fat feeding on the secretion of lipoproteins into the intestinal extracellular fluid. These conclusions coincide with those obtained by other workers from studies of apolipoprotein B dynamics in isolated hepatocytes and in the hepatoma-derived liver cell line, Hep G2. The mechanisms underlying these phenomena are as yet unresolved.
16
Orthey, Perry S. "Simulation of fluid mixing in the small intestine." Master's thesis, Temple University Libraries, 2015. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/342623.
Анотація:
Mechanical EngineeringM.S.M.E.
There are many gastrointestinal diseases, such as Crohn’s disease, which can be treated effectively with topical, localized medicine delivered to the intestinal wall through the gastrointestinal tract by the use of a targeted drug delivery capsule. The success of such a delivery method is contingent on the properties of the fluid flow near the delivery site; specifically, how well-mixed the medicine will be in the chyme so that it can act on the intestinal wall. Pursuant to understanding the mixed state of the chyme, several fluid simulations were performed with ANSYS Fluent, simulating different types of muscular contractions. Fluid particles – which were originally segregated into three sections of the simulated small intestine – were tracked, and simulation results were compared based on how well-distributed the tracked particles were at the end state, using the second moment of distribution. The results of this comparison have revealed that there is little difference between the mixing produced by segmentation in a 3.0 cm diameter small intestine and that produced in a 2.0 cm diameter small intestine. Results have also shown little difference between mixing produced when the segmentation contractions vary qualitatively in any of several ways. There is, however, some difference between distribution produced by segmentation contractions and peristaltic, or propulsive, contractions. This work could be further pursued with more simulations; of different types of contractions, of contraction patterns with different properties, and with simulations with more comprehensive particle tracking. It would also be straightforward to incorporate analysis of the large intestine into the study.
Temple University--Theses
17
Chan, Kwong-leung. "Management of intestinal failure - parenteral nutrition, experimental small bowel transplantation and preservation injury of small bowel allograft." Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22237586.
18
Thompson, Fiona Marie. "Activation of the mucosal immune system and growth of the small intestine at weaning /." Title page, abstract and contents only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09pht4677.pdf.
19
Nickdel, Mohammad Barat. "Role of Th2 cytokines in Toxoplasma gondii infection." Thesis, University of Strathclyde, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248258.
20
Merediz, Elena Fernandez-Castaño. "Molecular characterisation of fructose transport in equine small intestine." Thesis, University of Liverpool, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400246.
21
Singha, Sakon. "Antigen presentation in the small intestine of the pig." Thesis, University of Bristol, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269258.
22
Inman, Charlotte Frances. "Dendritic cells in the small intestine of the pig." Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434744.
23
Walters, Rhodri J. "Ion channel regulation in small intestinal crypts." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318409.
24
陳廣亮 and Kwong-leung Chan. "Management of intestinal failure - parenteral nutrition, experimental small bowel transplantation and preservation injury of small bowelallograft." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31979610.
25
Randrian, Violaine. "Role of myosin IIA in the small intestine immunosurveillance by dendritic cells." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCB038/document.
Анотація:
Plusieurs méthodes de capture antigénique ont été décrites dans l’intestin grêle, surtout en cas d’infection: échantillonnage direct par les cellules dendritiques (DC), capture par les macrophages qui délivrent ensuite l’antigène aux DC du stroma, passage des antigènes à travers les cellules caliciformes. Des travaux antérieurs in vitro dans le laboratoire ont montré l’importance de la myosine IIA dans la coordination de la migration des DC avec la capture et de l’apprêtement antigénique. L’objectif de ma thèse était de combiner plusieurs méthodes d’imagerie telle que la microscopie intravitale, la microscopie confocale ex vivo et l’immunofluorescence sur tissus à la cytométrie en flux pour déterminer l’impact de la myosine IIA sur la capture antigénique in vivo. Cette étude montre que les DC patrouillent en permanence dans l’épithélium de l’intestin grêle, y compris hors conditions infectieuses. Elles sont recrutées dans la lamina propria (LP) et pénètrent dans l’épithélium par transmigration à travers la membrane basale qui sépare ces deux compartiments. La myosine IIA est indispensable à la transmigration de CD103+CD11b+DC. Ces événements de transmigration surviennent plus fréquemment dans les parties proximales de l’intestin grêle, duodénum and jéjunum, que dans l’iléon. Chez les souris adultes, ces DC ne sont pas recrutées sous l’influence du microbiote mais sont sensibles au rétinal, un métabolite de la vitamine A qu’elles transforment en une molécule active l’acide trans-rétinoïque (AtRA). D’après notre analyse transcriptomique, les DC intra-épithéliales constituent une population homogène dont le profil est distinct de celui de leurs homologues de la LP. Elles sont enrichies en ARN des voies liées à l’apprêtement antigénique, l’autophagie et les lysosomes. Ces résultats suggèrent qu’elles ont une fonction différente des CD103+CD11b+DC de la LP: elles n’agissent pas sur la prolifération ni la différenciation des lymphocytes T mais contrôlent spécifiquement l’effectif des lymphocytes intra-épithéliaux CD8+αβ. Ces découvertes reflètent l’importance de l’épithélium comme première ligne de défense contre les pathogènes. Elles soulèvent également de nouvelles questions concernant la régulation de la réponse immune dans l’épithélium et les interactions mutuelles entre la lumière intestinale, l’épithélium et le stroma des villositésSeveral routes for antigen capture have been described in the small intestine, mainly upon pathogenic infection: direct sampling by Dendritic Cells (DCs), sampling by macrophages that deliver antigens to DCs in the stroma, antigenic passage through goblet cells. Previous in vitro work in the lab showed that myosin IIA is essential to coordinate antigen uptake and processing with DC migration. The objective of my thesis was to combine several imaging methods including intravital microscopy, ex vivo confocal microscopy and immunofluorescence on gut tissue to flow cytometry in order to unravel the impact of myosin IIA on DC physiology in vivo. My work shows that CD103+CD11b+ DCs, which are unique to the gut, constantly patrol the epithelium of the small intestine at steady state: they are recruited from the lamina propria (LP) and penetrate into the epithelium by transmigrating through the basal membrane that separates these two compartments. DC transmigration requires myosin IIA in vivo. Remarkably, we found that DC transmigration into the epithelium occurs mainly in the upper parts of the small intestine, the duodenum and the jejunum, but is not observed in the ileum. DC transmigration does not require the gut microbiota but relies on retinal, a vitamin A metabolite of that they convert into its active form all-trans retinoic acid (AtRA). Strikingly, single cell RNA-seq showed that intra-epithelial CD103+CD11b+ DCs constitute a homogenous cell population with a distinct transcriptomic signature from their LP counterpart. They are enriched with RNA related to antigen presentation, autophagy and lysosome pathways. Our results further suggest that these cells have a different function from LP CD103+CD11b+ DCs, as they do not significantly impact proliferation or differentiation of T helper lymphocytes but control the CD8+αβ intraepithelial lymphocytes (IELs) pool. These findings highlight the importance of the epithelial tissue as a first line of defense against pathogens in the upper parts of the small intestine. They also raise new questions about the regulation of the immune response in the epithelium and the mutual influences between lumen, epithelium and intestinal lamina propria
26
PAULINO, Barbara Costa. "Consequências do uso de soro de leite de cabra sobre parâmetros bioquímicos, morfologia e microbiota fecal de ratas e filhotes jovens alimentados com dieta ocidentalizada desde a vida perinatal." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/18453.
Анотація:
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CNPQ
A dieta ocidentalizada, rica em lipídeos, açúcar, sódio e alimentos processados e ultra processados tem sido apontada como um dos mais relevantes fatores associados ao excesso de peso/obesidade, comorbidades e distúrbios fisio-metabólicos observados em estudos epidemiológicos e experimentais em animais. O objetivo do presente estudo foi investigar os efeitos do soro de leite de cabra sobre o estado nutricional, microbiota, histologia intestinal e parâmetros bioquímicos de ratas e filhotes alimentados com dieta ocidentalizada. Foram utilizados 8 machos e 24 fêmeas da linhagem Wistar (da colônia do Departamento de Nutrição da Universidade Federal de Pernambuco) para o acasalamento dos animais. Ratas gestantes foram divididas em quatro grupos experimentais de acordo com a dieta: Controle ou Ocidentalizada e a suplementação ou não com soro de leite de cabra. Evolução ponderal e consumo alimentar das ratas seguiram por todo experimento. Ao desmame, as ratas e metade da prole de machos de cada ninhada foram eutanasiados para análise dos parâmetros bioquímicos, histologia intestinal, micro-organismos fecais. Metade dos filhotes foi submetida aos mesmos acompanhamentos e eutanasiados aos 45 dias de vida. A suplementação com soro de leite de cabra modificou poucos parâmetros nas ratas com exceção da alteração da quantidade de lactobacilos totais, que nos grupos controles com solução salina apresentaram uma média de 7,34±0,08 log.UFC/g-1 e 6,43±0,31 log.UFC/g-1 e no suplementado 7,79±0,30 log.UFC/g-1 e 6,94±0,45 log.UFC/g-1 para ratas com dieta ocidentalizada e padrão, respectivamente. Nos filhotes, a suplementação com soro de leite de cabra promoveu redução no ganho de peso e dos depósitos de gordura abdominal, alteração bioquímica, aumentou em 15% a contagem de lactobacilos e em 13% as enterobactérias. Além disso, minimizou o desgaste de células intestinais, limitando o processo inflamatório observado nos alimentados com dieta ocidentalizada. Dessa forma, pode-se sugerir que o soro de leite teve potencial efeito na microbiota fecal e morfologia intestinal, e que esses efeitos parecem depender da idade e do período de suplementação.
The westernized diet rich in fat, sugar, sodium and processed foods and processed ultra has been identified as one of the most important factors associated with overweight / obesity, comorbidities, and physiological and metabolic disorders observed in epidemiological and experimental studies in animals. The aim of this study was to investigate the effects of serum of goat milk on the nutritional status, microbiota, intestinal histology and biochemical parameters of rats and offispring fed westernized diet. Were used 8 male and 24 female Wistar (the colony of the Department of Nutrition at the Federal University of Pernambuco) for mating of animals. Pregnant rats were divided into four groups according to the diet: control or Westernized and supplemented or not with serum from goat milk. weight gain and food consumption of rats followed throughout the experiment. At weaning, rats, half male offspring in each litter were sacrificed for analysis of biochemical parameters, intestinal histology, faecal micro-organisms. Half of the pups was subjected to the same accompaniments and euthanized at 45 days of life. Supplementation with goat whey modified few parameters in rats with the exception of changing the amount of total lactobacilli that in control groups with saline had a mean of 7,34 ± 0,08 log.UFC/g-1 and 6, 43 ± 0,31 log.UFC/g1 and supplemented 7,79±0,30 log.UFC/g-1 and 6,94 ± 0,45 log.UFC/g-1 to rats with westernized diet and standard, respectively. In puppies, supplementation with goat whey promoted reduction of 200% in weight gain and deposits of abdominal fat, biochemical change, increased by 15% to lactobacillus count and 13% enterobacteria. In addition, minimized wear of intestinal cells by limiting the inflammatory process observed in fed westernized diet. Thus, it can be suggested that the whey had potential effect on fecal microbiota and intestinal morphology, and that these effects appear to depend on the age and supplementation period.
27
Pascal, Maud. "Innate Lymphoid Cells under Neuronal Control in the Small Intestine : vasoactive Intestinal Peptide potentiates ILC2 and ILC3 functions." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS318.
Анотація:
L’intestin est une vaste surface de l’organisme constamment exposée aux substances ingérées et aux nombreux micro-organismes qui colonisent sa muqueuse. Afin d’assurer le maintien de son intégrité, plusieurs dispositifs de reconnaissance et de défense impliquent cellules immunitaires et neurones, faisant de lui un organe de choix pour l’étude des interactions neuroimmunes. La compréhension des éléments assurant un fonctionnement coordonné des Systèmes immunitaire (SI) et Nerveux (SN) dans l’intestin reste cependant partielle. Ce travail a porté sur l’étude des mécanismes régissant le fonctionnement intégré des SN et SI de l’intestin suite à une prise alimentaire. Nous démontrons que la libération de Peptide Intestinal Vasoactif (VIP) suite à une prise alimentaire impacte la fonction de cellules clés dans l’organisation de l’immunité intestinale, les cellules lymphoïde innées (ILC). Pour la première fois, on démontre qu’un neuropeptide modifie de manière anticipée la biologie des ILC2 et des ILC3 pour potentialiser l’effet de cytokines inductrices caractéristiques des immunités de type 2 ou de type 3, permettant une activation rapide et conséquente des ILC. Ce travail complexifie le réseau de régulation du fonctionnement des ILC et dévoile un nouveau rôle du VIP dans le maintien de l’homéostasie intestinale via sa capacité à anticiper et potentialiser les réponses immune de manière intégrée. La compréhension de ce nouveau mécanisme d’interactions neuroimmunes dans l’intestin ouvre la voie vers le développement de nouvelles stratégies thérapeutiques basées sur les propriétés du VIP pour prévenir et traiter des maladies infectieuses et inflammatoires de l’intestinThe intestine represents an extremely wide interface constantly exposed to substances that we ingest and to numerous micro-organisms that colonize its mucosae. Several mechanisms of recognition and defense involving both immune cells and neurons exist to ensure protection of the gut, setting the gut as a paradigm for neuroimmune interactions. However, how the nervous and immune systems coordinate and synchronize their action in the gut remain unclear. In this thesis, I aimed to elucidate the mechanisms underlying one type of neuroimmune communication occurring in the gut, during a physiological process: feeding. In this context, I demonstrated that the food-induced release of the Vasoactive Intestinal Peptide (VIP) impacts the function of the recently discovered “gatekeepers” of the gut immune system, Innate Lymphoid Cells (ILCs). For the first time, I showed that a neuropeptide induces an anticipatory priming of both ILC2 and ILC3, which could potentiate the effect of the canonical type 2 and type 3 inducer cytokines to lead a rapid and strong activation of ILCs. This work provides new insights in the highly complex regulatory network of ILCs and uncovers a new role for VIP in maintaining gut homeostasis through its ability to prime and eventually boost immune responses in an integrated and context dependent manner. The understanding of the neuroimmune interplay involving VIP in the small intestine opens the path toward the development of new therapeutic strategies based on VIP properties to treat infectious and inflammatory diseases of the gastrointestinal tract
28
Cong, Diem Huyen Ton Nu Quy. "Intestinal absorption and availability, a vascular perfusion study of the rat small intestine with benzoic acid." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0016/MQ54173.pdf.
29
Collins, Alison Jane. "Ontogeny of lactase-phlorizin hydrolase in the pig small intestine." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388687.
30
Sheppard, David N. "Ion channel regulation in enterocytes from Necturus maculosus small intestine." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334271.
31
Marsh, Victoria. "Analysing the role of Pten in the murine small intestine." Thesis, Cardiff University, 2008. http://orca.cf.ac.uk/54772/.
Анотація:
Colorectal cancer is a significant cause of mortality in the UK, being the third most common cancer type. Activating mutations within the Phosphoinositide 3-Kinase/Akt pathway have previously been reported in a significant proportion of sporadic colorectal cancers. Phosphatase and tensin homolog mutated on chromosome 10 (PTEN) is an antagonist of the PI3K/Akt pathway, and as such is a well characterised tumour suppressor. In this thesis I aimed to characterise the role of Pten within the murine intestine, with respect to homeostasis of otherwise normal epithelium, and also in the context of activated Wnt signalling and activation of the oncogene k-Ras. This has been achieved using a Cre-LoxP-based approach to conditionally delete Pten specifically from the adult murine intestinal epithelium. Deletion of Pten alone is reported here to have little immediate effect on normal homeostasis of the intestinal epithelium or the intestinal stem cell. At extended timepoints after Pten loss, delayed formation of hamartomas and adenomas within the intestine is reported. In the context of activated Wnt signalling, additional loss of Pten is found to accelerate tumourigenesis, resulting in adenocarcinoma formation. These lesions are characterised by strong activation and membrane localisation of Akt. Co-ordinate deletion of Pten and activation of k-Ras is reported here to show strong synergy in promoting the formation of both papillomatous lesions of biliary epithelia and widespread hyperplasia of the forestomach squamous epithelium. Lesions within the biliary epithelium are characterised by strong activation of Akt, with gall bladder lesions again showing membrane localisation of Akt. In the intestine, preliminary data reported here also indicates synergy between Pten loss and k-Ras activation in promoting hyperproliferation of the epithelium. Together, these data therefore indicate that, in normal intestinal epithelium, PTEN is a weak tumour suppressor, but is critical for suppressing neoplasia in the context of other mutations.
32
Stow, Ruth Anne. "Purine nucleoside transport and metabolism across the rat small intestine." Thesis, University of York, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.258382.
33
Harper, Helen Margaret. "The induction of immune responses in the murine small intestine." Thesis, University of Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389589.
34
Tharakan, Ajay. "Modelling of physical and chemical processes in the small intestine." Thesis, University of Birmingham, 2009. http://etheses.bham.ac.uk//id/eprint/330/.
Анотація:
Chemical and physical processing in the small intestine is an important step for food digestion and absorption. Having reviewed the literature, a relevant model has been developed which enabled investigation into the fluid flow, mixing mechanisms and delivery of nutrients to the wall of the model small intestine. Designing, developing and using the Small Intestinal Model (SIM), a physical model of a section of the small intestine, mimicking the physiological contractions, allowed mass transfer to be measured using different process conditions and ingredients. Experiments were carried out using the SIM to study mass transfer, starch digestion and flow visualisation. While simulating the small intestinal flow profile, experiments have shown that the functional ingredient guar gum reduces the mass transfer coefficient of the model nutrient riboflavin. This together with computational modelling suggests an explanation for the observed functionality of guar gum to reduce the peak increase in blood glucose levels after ingestion of test meals. Industrial implications are to give a scientific and engineered design methodology for novel food formulations by understanding the food product behaviour in the SIM. Optimisation of formulation candidates going to the human trial stage and improvement of speed to market of new product introductions is intended.
35
Arora, Daleep Kumar. "Molecular characterisation of sweet taste receptor in horse small intestine." Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539467.
36
Shepherd, Emma Jayne. "Oligopeptide transport across the basolateral membrane of rat small intestine." Thesis, University of York, 2001. http://etheses.whiterose.ac.uk/14038/.
Анотація:
Oligopeptide transport in rat small intestine has been studied in intact tissue, using the luminally and vascularly perfused isolated jejunum in situ technique, and a hydrolysis-resistant dipeptide (D-Phe-L-Gln). The data in this thesis can be divided into two main sections: (l) identification of the transporter proteins, and (2) short-term regulation of transport. The basolateral peptide transporter protein has not, to date, been identified. A candidate protein was identified from membrane vesicles by a photo affinity labelling technique using a dipeptide derivative ([4-azido-3,5-3H-D-Phe]-L-Ala), previously shown to be an efficient substrate for the basolateral transporter. The labelled candidate protein was successfully isolated by 2-DE, which revealed an apparent Mr of 112 ± 2 kDa and a pI of approximately 6.5. Initial sequence analysis, tryptic digestion followed by MALDI-TOF analysis and Q-TOF fragmentation of a tryptic peptide, produced a peptide fingerprint and a sequence tag of 9 amino acids, respectively, which, together, did not completely and conclusively match to any known protein sequence contained within databases, therefore suggesting that the 112 kDa protein may be novel. Short-term regulation of peptide transport was also investigated using the vascular perfusion method. An amino acid-sensing pathway was discovered, using L-Leucine as the regulator, involving protein kinase cacades leading to p70S6k activation and subsequent stimulation ofbasolateral membrane peptide transport. A major conclusion arising from the data was the distinction between PepTl and the basolateral transporter, i.e. the sequence data obtained from the candidate protein did not match to the PepTl sequence; in addition there appeared to be distinct mechanisms of regulatory control at the two membranes. Efficient delivery of peptidomimetic drugs when adminsitered by the oral route requires knowledge of short-term regulation of intestinal peptide transport, in addition to the sequence and structure of the basolateral transporter. This thesis provides essential information, which may eventually contribute to the unequivocal identification and sequencing of the intestinal basolateral peptide transporter, ultimately leading to the future development of compounds with high bioavailability.
37
HIRNING, LANE DURAND. "MULTIPLE PEPTIDE RECEPTORS AND SITES OF ACTION IN THE CANINE SMALL INTESTINE (OPIOIDS, MOTILIN, TACHYKININS, INTESTINAL MOTILITY, SUBSTANCE P)." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/188150.
Анотація:
Motility of the small intestine is a result of complex neurochemical and hormonal interactions within the intestine. The net motility (contraction) of the intestine is a balance of the influences from the central nervous system, enteric nervous system and hormonal changes in the body. Recently, the discovery of several peptide neurotransmitters common to the brain and the intestine has stimulated new research into the influence of these novel neurotransmitter candidates on intestinal motility at the level of the enteric (intestinal) nervous system. The present studies examined the contractile actions of three families of peptides, the opioids, tachykinins and motilin. Each of these peptide groups has been localized in the intestine, and suggested to function in the control of intestinal motility. The peptides were administered by intraarterial injection to isolated segments of canine small intestine and the resulting contractile activity measured. The results of these experiments demonstrate that all of these peptides may elicit contractile activity of the intestine in very low doses. These actions were further examined, using pharmacological antagonists, to determine the mechanism of action and the receptor types involved in the contractile actions. The opioid peptide induced responses were found to be mediated by two receptor types, mu and delta, located on the enteric nerve and smooth muscle, respectively. Similarly, the tachykinin induced contractions were also found to be due to actions on two receptor types, SP-P and SP-K, located on the nerve and muscle layers, respectively. These data suggest that the opioids and tachykinins may have multiple functions in the intestine dependent on the site of action and the receptor type involved in the response. Administration of motilin induced long-lasting contractile patterns in the intestine. The results also suggest that the actions of motilin are mediated by intermediate neurons of the enteric plexes which synapse on terminal cholinergic motor neurons.
38
Lindell, Monica. "Expression of Genes Encoding for Drug Metabolism in the Small Intestine." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3601.
39
Tallkvist, Jonas. "Nickel permeation pathways in the small intestine and the olfactory system /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1997. http://epsilon.slu.se/avh/1997/91-576-5422-0.gif.
40
Liu, Liming. "Dendritic cells in the small intestine : isolation, characterisation and functional studies." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306554.
41
Nowocin, A. K. "Development of a biologically derived acellular construct for small intestine replacement." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1336065/.
Анотація:
Introduction: Short bowel syndrome is characterised by a severe reduction in the amount of functional intestine available as an absorptive surface. Attempts to lengthen the intestine by interposition of artificial tubular scaffolds juxtaposed between healthy tissues have shown limited success. Transplantation is limited due to organ shortage. The most promising solution may be implantation of tissue-engineered small intestine using natural scaffold. Materials and Results: Using a completely novel approach, up to 30cm lengths of ileum with the attached vasculature were harvested from porcine donors. Separate intestinal and vascular loops were identified and de-cellularised using individually tailored detergent-enzymatic protocols. The resulting scaffold was compared to native tissue in terms of retention of cellular and nuclear remnants, as well as structural and functional proteins. Its biocompatibility was assessed by subcutaneous implantation of 1cm2 pieces into rat recipients. The remodeling fate of grafts was determined by time related changes in the ratio of sub-populations of residual macrophages. Its mechanical strength and ease of handling was evaluated by performing a left-sided nephrectomy in an unrelated pig model, followed by end-to-end anastomosis of the de-cellularised scaffolds’ mesenteric vasculature to the appropriate renal artery and vein. In the last stage, porcine organoid units were isolated and their yield estimated for future in vitro studies. Conclusions: It is possible to simultaneously de-cellularise two different tissues of varying cellular configuration and composition effectively and efficiently over a relatively short period of time. The two key features of the de-cellularised scaffold are that 1) the scaffold has in place the necessary architectural topography of small intestine (including mucosal villi) and molecular cues for optimum re-cellularisation and 2) the attached vascular tree provides an ideal conduit for re-cellularisation using either vascular committed endothelial or progenitor cells. Ultimately, this scaffold can be used for constructing long segments of bio-engineered intestine with the possibility of immediate blood supply and re-vascularisation.
42
Nagy, Amy Dae. "Apoptosis in the equine small intestine following experimental ischemia-reperfusion injury." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/43374.
Анотація:
This study was aimed at characterizing the apoptotic response equine small intestine subjected to experimental ischemia-reperfusion injury and determining if use of an angiotensin converting enzyme inhibitor (enalaprilat) would ameliorate the apoptotic response. It was designed to determine if mucosal epithelial cells undergo apoptosis during the ischemia phase and also examined if apoptosis is significantly exacerbated by reperfusion. It also investigated whether administration of enalaprilat decreased reperfusion injury secondary to reduced enterocyte apoptosis. Injury was induced using a low flow model of I-R. During celiotomy a single loop of jejunum was isolated and arterial flow decreased to 20% of baseline for one hour and complete occlusion for a second hour. Reperfusion was monitored for 3 hours. A control group (n=6) were not treated while the treatment group (n=6) received 0.5 mg/kg enalaprilat in 0.9% NaCl immediately following ischemia. Jejunal samples were taken prior to the induction of ischemia, immediately post-ischemia and at 1, 2 and 3 hours of reperfusion. Samples were evaluated for gross tissue pathology with standard hematoxylin and eosin staining, the presence of apoptotic cells via TUNEL staining, and gene expression of three apoptosis related genes (bax, bcl-2, p53) using qPCR. Serum enalaprilat and ACE concentrations were determined from blood samples drawn concurrent with jejunal sampling using HPLC/MS and standard HPLC. Plasma enalaprilat concentrations were comparable to previous reports in awake horses. Enalaprilat appeared to have no effect on serum ACE concentrations, however a significant spike in ACE concentration occurred in the treatment group at 1 hour of reperfusion (P=0.0001). Grade of mucosal damage was not significantly different between control and treatment groups at any time point. Subjectively apoptotic index appeared to be higher in the treatment group at end ischemia and during reperfusion. There were no changes in expression of p53 or bcl-2 in either group. Bax expression was significantly decreased (P= 0.02) in the control group at 2 hours of reperfusion. Based on our data administration of an ACE inhibitor during anesthesia in horses with an ischemic segment of intestine confers no protective benefit and may be associated with increased intestinal injury and apoptosis. Lack of expression of p53, bax and bcl-2 suggests another apoptotic mechanism in equine ischemic intestine.Master of Science
43
Williams, Jonathan. "Pathological epithelial cell apoptosis and shedding in the murine small intestine." Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/15293/.
Анотація:
The intestinal epithelium represents a critical component of the gut barrier and is composed of a single layer of intestinal epithelial cells (IECs) held together by tight junctions. This epithelium prevents the entrance of harmful microorganisms, antigens and toxins from the gut lumen into the circulation. Small intestinal homeostasis is maintained by the rate of shedding of senescent enterocytes from the villus tip exactly matching the rate of generation of new cells in the crypt. However, in various localised and systemic inflammatory conditions, intestinal homeostasis may be disturbed as a result of increased IEC shedding. Such pathological IEC shedding may cause transient gaps to develop in the epithelial barrier and result in increased intestinal permeability. Although pathological IEC shedding has been implicated in the pathogenesis of inflammatory bowel disease, understanding of the underlying mechanisms remains limited. This thesis describes the development of a murine model to study this phenomenon, as IEC shedding in this species is morphologically analogous to humans. IEC shedding was induced by systemic lipopolysaccharide (LPS) administration in wild-type C57BL/6 mice, and mice deficient in TNF-receptor 1 (Tnfr1-/-), Tnfr2-/-, Nuclear Factor kappa B1 (Nfkb1-/-) or Nfkb2-/-. IEC apoptosis and cell shedding was quantified using immunohistochemistry for active Caspase-3 and gut lumen to systemic circulation permeability was assessed by measuring plasma fluorescence following fluorescein isothiocyanate-dextran gavage. LPS at doses ≥0.125mg/kg induced rapid villus IEC apoptosis and cell shedding which was maximal at 1.5h. This coincided with significant villus shortening, fluid exudation into the gut lumen and diarrhoea. A significant increase in gut to circulation permeability was observed at 5h. TNFR1 was essential for LPS-induced IEC apoptosis and shedding and the fate of the IEC was also dependent on NFκB, with signalling via NFκB1 favouring cell survival, and via NFκB2 favouring apoptosis. This model will enable investigation of the importance and regulation of pathological IEC apoptosis and cell shedding in intestinal and systemic diseases.
44
Murskyj, Mark Joseph. "THE UPTAKE AND TRANSPORT OF NANOPARTICLES IN THE MURINE SMALL INTESTINE." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/1032.
Анотація:
The small intestine is a mucosal surface that is exposed to a large number of antigens from food and commensal organisms and preferentially develops a state of unresponsiveness or tolerance to these antigens. Epithelial cells take up soluble antigens leading to the development of oral tolerance. Goblet cells are also capable taking up soluble antigen. M cells, known for the uptake of particulate antigen, are found primarily in the follicle-associated epithelium, which is not critical for oral tolerance. To determine whether intestinal epithelial cells (IECs) take up particulate antigen, fluorescent nanoparticles 0.02 - 2 μm in diameter were administered to mice. It was found that IECs and goblet cells take up nanoparticles ≤40 nm in diameter and these nanoparticles are rapidly transported to the mesenteric lymph nodes, an organ important for the induction of tolerance to dietary antigens and immunity to pathogens.
45
Price, Barrie Anthony. "The effects of small bowel transplantation on the intraluminal flora of the small intestine in the rat." Thesis, King's College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307376.
46
Reynolds, Krista Lynn. "Effects of high incubation temperature on the developing small intestine and yolk sac of broiler chicks with insight into goblet cell development in the small intestine early posthatch." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/102122.
Анотація:
The incubation period is crucial for development and overall quality of a chick. The selection for fast growing broilers has allowed the birds to reach market weight at a faster rate making the incubation period a larger portion of a broiler's life. A faster growth rate can lead to the release of more metabolic heat inside of the egg toward the second half of incubation because the embryo shifts to a homeothermic state. More heat being released into the incubator can cause the incubation temperature to rise if the incubator is not electronically regulated or cannot be ventilated properly due to malfunction. A high incubation temperature can impact the hatchability, growth, and development of the chick. This thesis provides a more in-depth analysis of the effects of high incubation temperature (37.5°C versus 39.5°C) on the developing small intestine and yolk sac, which provide the chick with nutrients posthatch and during embryogenesis. Studying these organs and mechanisms occurring during this time could potentially indicate why chicks from eggs subjected to a higher incubation temperature are not developing and growing properly. Chicks from eggs incubated at a higher temperature had lower body weights, lower hatchability and lower villus height in the duodenum, jejunum, and ileum. There were also differences seen in the depth of the crypt, which is the site for stem cells. Chicks from eggs incubated at a higher temperature had a lower crypt depth in the duodenum and jejunum. There was no difference in the expression of the intestinal stem cell marker olfactomedin 4 (Olfm4) and mucin 2, which is secreted by goblet cells and forms mucus. In the yolk sac, heat shock proteins (HSP) 70 and 90 were elevated at embryonic day 15, and HSP90 still remained elevated at embryonic day 17. Chicks from eggs incubated at a higher temperature showed greater expression of peptide transporter 1 and avian beta-defensin 10 mRNA at embryonic day 13. Even though small intestinal morphology was impacted early posthatch and expression of genes in the yolk sac were elevated at embryonic day 13, there does not seem to be a long-lasting effect on the development of the small intestine or the yolk sac. It is still important to study the impact of the incubation environment to understand the development and growth of the chicks and how different incubation factors can impact the overall hatchability and health of the chick.Master of Science
47
Keefe, Dorothy Mary Kate. "The effect of cytotoxic chemotherapy on the mucosa of the small intestine /." Title page, table of contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09MD/09mdk26.pdf.
48
Moghaddami, Mahin. "Characterization of isolated lymphoid aggregations in the mucosa of the small intestine /." Title page, abstract and contents only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09phm6959.pdf.
Анотація:
Thesis (Ph.D.)--University of Adelaide, Dept. of Microbiology and Immunology, 1999.Errata & addenda tipped in behind back end paper. Copies of author's previously published articles in pocket on back end-paper. Bibliography: leaves 147-194.
49
Wu, Julie C. Y. "Cellular analysis of calbindin and calbindin mRNA expression in chick small intestine." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319552.
50
Kitchen, Paul Anthony. "A study of the effects of growth factors on the small intestine." Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401868.