Comme nous l’indiquions dans le But du Travail, le mélanome figure parmi les cancers associés aux pronostics les plus sombres, et ce en raison de son taux de réponse très faible à la radiothérapie et à la chimiothérapie. Cette résistance à la radiothérapie et à la chimiothérapie provient essentiellement du fait que les cellules de mélanomes sont résistantes à l’apoptose, et que la radiothérapie ainsi que bon nombre d’agents chimiothérapiques induisent la mort des cellules cancéreuses en y induisant l’apoptose. Nous avons voulu investiguer les rôles de la gastrine et de la galectine 1 sur le comportement biologique des cellules de mélanomes afin de voir s’il était possible de proposer la gastrine et/ou la galectine 1 comme nouvelles cibles thérapeutiques potentielles dans le cas du mélanome. Notre stratégie de recherche est basée sur le principe (démontré sur le plan expérimental par de nombreuses études) selon lequel les cellules cancéreuses migrantes résistent à l’apoptose, et sont dès lors protégées contre les effets pro-apoptotiques de la chimiothérapie et de la radiothérapie qui représentent la quasi totalité de l’arsenal thérapeutique dont disposent les oncologues pour combattre les cancers. Diverses études expérimentales ont démontré que le fait de réduire le taux de migration de cellules cancéreuses résistantes à l’apoptose conférait à celles-ci une sensibilité accrue aux agents pro-apoptotiques. Nos résultats démontrent que la gastrine modifie de manière très significative les propriétés migratoires des cellules de mélanomes, sans toutefois modifier leur sensibilité à des agents pro-apoptotiques. Au contraire, la gastrine protègerait les cellules de mélanomes contre l’apoptose. Nous démontrons également dans notre travail, in vivo, un rôle pro-angiogénique pour la gastrine au sein de xénogreffes de mélanomes humains. Signalons que notre travail est le premier à démontrer un rôle potentiel de la gastrine au niveau de la biologie des mélanomes, tout au moins sur le plan expérimental. Tout comme nous l’avons observé pour la gastrine, la galectine 1 semble également conférer aux cellules de mélanomes un certain degré de résistance aux agressions chimiothérapiques. Cette fois, le fait de diminuer le taux d’expression de la galectine 1 au sein de cellules du mélanome murin expérimental B16F10 (qui exprime des quantités importantes de galectine 1) renforce l’effet thérapeutique du témozolomide qui est une molécule cytotoxique. Cet effet semble survenir, tout au moins partiellement, suite à une diminution du taux d’expression de la protéine Hsp70 (suite à la diminution du taux d’expression de la galectine 1), avec pour conséquence une augmentation de la mort cellulaire par perméabilisation de la membrane des lysosomes. Nous proposons une nouvelle approche thérapeutique pour combattre les mélanomes en faisant appel à la technique des petits ARN interférants (siRNA), dirigés dans le cas présent contre la galectine 1.

The syndrome known as Gastric Dilation Air Sacculitis (GDAS) has recently been described by Lumsden et al. (2002) for Chinook salmon (Oncorhynchus tshawytscha, Walbaum), in seawater (SW) culture in New Zealand. The syndrome is characterised by distended abdomens, gastric dilation and air sacculitis, increased feed conversion ratios (FCR) and mortality. Consequently, financial returns on affected stocks are greatly reduced. A study into the epidemiology and physiology of the syndrome was initiated, working with the major aquaculture company, The New Zealand King Salmon Company (NZKS). The study revealed causative factors of GDAS. GDAS was experimentally induced only in saltwater by feeding a commercially manufactured low-cohesion pelleted diet. Control groups were fed a different diet with high physical cohesion. Low-cohesion pellets have previously been associated with a high incidence of GDAS in commercial sea cages. These data implicated osmoregulatory stress and physical properties of the feed in GDAS development. In addition, gastrointestinal (GI) physiology in GDAS -affected and -control fish was characterised. The process of GDAS development in O. tshawytscha is characterised by a loss of smooth muscle tone of the stomach as it distends. Laplace's law (P= 2T/r, where P is the distending pressure, T is the tension in the wall and r is the radius of the cylinder) predicts that unless muscle mass increases, the ability of the stomach wall to contract will be lost and consequently a loss of GI motor function will result. Therefore, GI circular smooth muscle integrity in terms of (1) stimulated and maximal contractility, (2) osmoregulatory ability of the intestine and the (3) control of the GI system was studied in pathologically affected (+ve) and unaffected (-ve) smolt. Affected fish showed changes in GI circular smooth muscle function and osmoregulatory dysfunction. Feeding different diets induced distinct gastric evacuation patterns. The intestinal brake hypothesis is presented and argued to be the probable mechanism for GDAS development. GDAS (+ve) serum showed the presence of factors capable of contracting gut smooth muscle. In addition, potential humoral mediators of the intestinal brake in fish were investigated.

The syndrome known as Gastric Dilation Air Sacculitis (GDAS) has recently been described by Lumsden et al. (2002) for Chinook salmon (Oncorhynchus tshawytscha, Walbaum), in seawater (SW) culture in New Zealand. The syndrome is characterised by distended abdomens, gastric dilation and air sacculitis, increased feed conversion ratios (FCR) and mortality. Consequently, financial returns on affected stocks are greatly reduced. A study into the epidemiology and physiology of the syndrome was initiated, working with the major aquaculture company, The New Zealand King Salmon Company (NZKS). The study revealed causative factors of GDAS. GDAS was experimentally induced only in saltwater by feeding a commercially manufactured low-cohesion pelleted diet. Control groups were fed a different diet with high physical cohesion. Low-cohesion pellets have previously been associated with a high incidence of GDAS in commercial sea cages. These data implicated osmoregulatory stress and physical properties of the feed in GDAS development. In addition, gastrointestinal (GI) physiology in GDAS -affected and -control fish was characterised. The process of GDAS development in O. tshawytscha is characterised by a loss of smooth muscle tone of the stomach as it distends. Laplace's law (P= 2T/r, where P is the distending pressure, T is the tension in the wall and r is the radius of the cylinder) predicts that unless muscle mass increases, the ability of the stomach wall to contract will be lost and consequently a loss of GI motor function will result. Therefore, GI circular smooth muscle integrity in terms of (1) stimulated and maximal contractility, (2) osmoregulatory ability of the intestine and the (3) control of the GI system was studied in pathologically affected (+ve) and unaffected (-ve) smolt. Affected fish showed changes in GI circular smooth muscle function and osmoregulatory dysfunction. Feeding different diets induced distinct gastric evacuation patterns. The intestinal brake hypothesis is presented and argued to be the probable mechanism for GDAS development. GDAS (+ve) serum showed the presence of factors capable of contracting gut smooth muscle. In addition, potential humoral mediators of the intestinal brake in fish were investigated.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2000. / Härtill 4 uppsatser.

Made available in DSpace on 2014-06-11T19:33:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-05-14Bitstream added on 2014-06-13T19:44:13Z : No. of bitstreams: 1 pereira_jg_dr_jabo.pdf: 2012412 bytes, checksum: a771199b8c53c2ad3c164715147a19cf (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O Kinosternon scorpioides é uma tartaruga de água doce conhecida como jurará. O objetivo do presente trabalho foi identificar serotonina, gastrina, enteroglucagon e motilina em esôfago, estômago e duodeno de K.scorpioides por meio da técnica de imunohistoquímica. Os resultados mostraram que as células imunorreativas à serotonina estavam presentes no epitélio na região caudal do esôfago, nas glândulas gástricas das regiões cárdica, fúndica e pilórica. As células produtoras de gastrina foram identificadas em grande quantidade entre as células da região pilórica e no epitélio de revestimento do duodeno, e em número reduzido na região cárdica. O enteroglucagon foi identificado na superfície dos cílios, no epitélio de revestimento da mucosa esofágica, nas fibras nervosas da lâmina própria e submucosa; no estômago estava localizado entre as células das glândulas cárdicas e fúndicas em número moderado, e aparentemente em maior quantidade nas pilóricas. No duodeno, o enteroglucagon foi identificado na superfície dos microvilos, no epitélio de revestimento, nas fibras nervosas da lâmina própria e submucosa. A motilina foi identificada apenas entre as fibras nervosas dos órgãos estudados. Em conclusão, as células imunorreativas à serotonina, gastrina, enteroglucagon e motilina foram identificadas em todos os órgãos estudados. Entretanto, nos diferentes segmentos houve diferença quanto à distribuição e frequência dessas células / Kinosternon scorpioides is a freshwater turtle known as “jurará”. The aim of this work was to identify peptides serotonin, enteroglucagon, gastrin and motilin in esophagus, stomach and duodenum by immunohistochemical techniques. The results showed that immunoreactive cells for serotonin were presented in the epthitelium of distal region of the esophagus, in glands of cardiac, fundic and pyloric region of the stomach and in the surface of duodenum epithelium. These cells were classified as open and closed type. The cells immunoreactive for gastrin were abundant in pyloric region and duodenum epitheliun, few numerous in cardiac region and absent in the esophagus. Cells rich in enteroglugagon were identified in the cilia surface, in the epithelium of esophagus, among nervous fibers of lamina propria and submucosa; in the stomach, these cells were observed in small number cardiac and fundic glands, however in pyloric region they were abundant. In duodenum, they were observed in microvillus surface, epithelium and nervous fibers of both lamina propria and submucosa. On the other hand, cells that produce motilin were observed just among lamina propia and submucosa. In conclusion, cells rich in serotonin, gastrin, enteroglugagon and motilin were found in all studied organs. However it was observed differences in the segments regarding distribution and frequency of these cells

Die transkriptionelle Aktivierung des HDC Gens sowie des Chromogranin A Gens in ECL-Zellen der Magenmucosa repräsentiert einen zentralen Mechanismus der Säureregulation durch Gastrin und scheint ausserdem Bedeutung für die Pathogenese der gastroduodenalen Ulkuskrankheit zu haben. Unsere Untersuchungen identifizieren erstmals die molekularen Mechanismen der Gastrin-abhängigen Regulation beider Gene und definieren die beteiligten Transkriptionsfaktoren, regulatorischen DNA-Elemente und intrazellulären Signalwege. Des weiteren wurde durch transgene Untersuchungen die transkriptionelle Regulation des ChromograninA Gens in vivo bestätigt und die neuroendokrin-spezifische Expression eines 4.8kB-langen CgA-Promotorfragmentes demonstriert. Als pathobiologisch relevante Aktivatoren des HDC Gens konnten oxidativer Stress sowie die H. pylori Infektion identifiziert und hinsichtlich ihrer molekularen Wirkungen auf das Schlüsselgen der Histaminsynthese im Magen charakterisiert werden. Diese Ergebnisse dokumentieren einen potentiellen Mechanismus für die Interaktion beider Stimuli mit den physiologischen Regelkreisen der Magensäureregulation und können durch die Definition neuer molekularer Angriffspunkte möglicherweise zur Entwicklung innovativer Therapieansätze beitragen. / Transcriptional activation of the genes encoding histidine decarboxylase and chromogranin A represents a key mechanism of gastrin-dependent acid regulation and also appears to be involved in the pathogenesis of gastroduodenal ulcer disease. Our results for the first time identify the molecular mechanisms underlying gastrin-dependent activation of both genes, and define the transcription factors, regulatory DNA elements and signal transduction pathways involved in this process. Furthermore, transgenic studies confirmed the principle of gastrin-dependent transcriptional activation of the chromogranin A gene in vivo, and demonstrated neuroendocrine-specific expression of a 4.8kB-CgA promotor fragment. In addition, the pathobiological stimuli oxidative stress and H. pylori were molecularly characterized regarding their activating effects on the key gene of gastric histamine sythesis. These results provide potential mechanisms for the interaction of both stimuli with regulatory circuits of gastric acid secretion, and can probably contribute via definition of new molecular targets to the development of inovative therapeutic strategies.

No description available.

Orientador: Célio Raimundo Machado / Banca: Ana Lucia Abreu-Silva / Banca: Cláudio César Fonseca / Banca: Márcia Rita Fernandes Machado / Banca: Nadia Delistoianov / Resumo: O Kinosternon scorpioides é uma tartaruga de água doce conhecida como jurará. O objetivo do presente trabalho foi identificar serotonina, gastrina, enteroglucagon e motilina em esôfago, estômago e duodeno de K.scorpioides por meio da técnica de imunohistoquímica. Os resultados mostraram que as células imunorreativas à serotonina estavam presentes no epitélio na região caudal do esôfago, nas glândulas gástricas das regiões cárdica, fúndica e pilórica. As células produtoras de gastrina foram identificadas em grande quantidade entre as células da região pilórica e no epitélio de revestimento do duodeno, e em número reduzido na região cárdica. O enteroglucagon foi identificado na superfície dos cílios, no epitélio de revestimento da mucosa esofágica, nas fibras nervosas da lâmina própria e submucosa; no estômago estava localizado entre as células das glândulas cárdicas e fúndicas em número moderado, e aparentemente em maior quantidade nas pilóricas. No duodeno, o enteroglucagon foi identificado na superfície dos microvilos, no epitélio de revestimento, nas fibras nervosas da lâmina própria e submucosa. A motilina foi identificada apenas entre as fibras nervosas dos órgãos estudados. Em conclusão, as células imunorreativas à serotonina, gastrina, enteroglucagon e motilina foram identificadas em todos os órgãos estudados. Entretanto, nos diferentes segmentos houve diferença quanto à distribuição e frequência dessas células / Abstract: Kinosternon scorpioides is a freshwater turtle known as "jurará". The aim of this work was to identify peptides serotonin, enteroglucagon, gastrin and motilin in esophagus, stomach and duodenum by immunohistochemical techniques. The results showed that immunoreactive cells for serotonin were presented in the epthitelium of distal region of the esophagus, in glands of cardiac, fundic and pyloric region of the stomach and in the surface of duodenum epithelium. These cells were classified as open and closed type. The cells immunoreactive for gastrin were abundant in pyloric region and duodenum epitheliun, few numerous in cardiac region and absent in the esophagus. Cells rich in enteroglugagon were identified in the cilia surface, in the epithelium of esophagus, among nervous fibers of lamina propria and submucosa; in the stomach, these cells were observed in small number cardiac and fundic glands, however in pyloric region they were abundant. In duodenum, they were observed in microvillus surface, epithelium and nervous fibers of both lamina propria and submucosa. On the other hand, cells that produce motilin were observed just among lamina propia and submucosa. In conclusion, cells rich in serotonin, gastrin, enteroglugagon and motilin were found in all studied organs. However it was observed differences in the segments regarding distribution and frequency of these cells / Doutor

Neuropeptides, such as substance P (SP) and bombesin/gastrin-releasing peptide (BN/GRP), and neurotrophins are involved in neuro-immunomodulatory processes and have marked trophic, growth-promoting and inflammation-modulating properties. The impact of these modulators in rheumatoid arthritis (RA) is, however, unclear. An involvement of the innervation, including the peptidergic innervation, is frequently proposed as an important factor for arthritic disease. Many patients with RA, but not all, benefit from treatment with anti-TNF medications. The studies presented here aimed to investigate the roles of neuropeptides, with an emphasis on BN/GRP and SP, and neurotrophins, especially with attention to brain-derived neurotrophic factor (BDNF), in human and murine knee joint tissue. The expression patterns of these substances and their receptors in synovial tissue from patients with either RA or osteoarthritis (OA) were studied in parallel with the levels of these factors in blood and synovial fluid from patients with RA and from healthy controls. Correlation studies were also performed comparing the levels of neuropeptides with those of pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6)]. Furthermore, the impact of anti-TNF treatment on the levels of BDNF in blood was investigated. In a murine model of RA, the expression of these substances on articular chondrocytes along with their expression in synovial tissue was investigated. The expression of BN/GRP in human synovial tissue was confined to fibroblast-like and mononuclear-like cells whereas SP was detected in nerve-related structures. Receptors for these neuropeptides (GRP-R and NK-1R) were frequently present in blood vessel walls, and on fibroblast-like and mononuclear-like cells. The expression of BDNF and its receptors, p75 neurotrophin receptor and TrkB, was mainly confined to nerve structures. The levels of SP, and particularly those of BN/GRP, in synovial fluid and peripheral blood correlated with the levels of pro-inflammatory cytokines. There were clearly more correlations between SP-BN/GRP and inflammatory parameters than between BDNF and these factors. Plasma levels of BDNF were decreased following anti-TNF-treatment. In the joints of the murine model, there was a marked expression of neurotrophins, neurotrophin receptors and NK-1R/GRP-R in the articular chondrocytes. The expression was down-regulated in the arthritic animals. A neurotrophin system was found to develop in the inflammatory infiltrates of the synovium in the arthritic mice. The results presented suggest that there is a local, and not nerve-related, supply of BN/GRP in the human synovial tissue. Furthermore, BN/GRP and SP have marked effects in the synovial tissue of patients with RA, i.e., there were abundant receptor expressions, and these neuropeptides are, together with cytokines, likely to be involved in the neuro-immunomodulation that occurs in arthritis. The observations do on the whole suggest that the neuropeptides, rather than BDNF, are related to inflammatory processes in the human knee joint. A new effect of anti-TNF treatment; i.e., lowering plasma levels of BDNF, was observed. Severe arthritis, as in the murine model, lead to a decrease in the levels of neurotrophin, and neurotrophin and neuropeptide receptor expressions in the articular cartilage. This fact might be a drawback for the function of the chondrocytes. Certain differences between the expression patterns in the synovial tissue of the murine model and those of human arthritic synovial tissue were noted. It is obvious that local productions in the synovial tissue, nerve-related supply in this tissue and productions in chondrocytes to different extents occur for the investigated substances.