No description available.

No description available.

No description available.

No description available.

No description available.

The gastrointestinal epithelium normally sealed by tight junctions, which act as a structural barrier and paracellular channels. Inflammation can increase the permeability of microvasculature that result in plasma leakage. Mammalian intestinal epithelium has many goblet cells which discharge mucus in the inflammatory response. The discharging mucus functioning is as a defensive barrier and lubricant. The mucus layer is the anatomical site at which the host first encounters gut bacteria, physical damage, and chemical stimulant. The heat shock response is one of the most primitive cellular defense mechanism. A variety of stressful situations including environmental (ultraviolet radiation or heavy metals), pathological (infections or malignancies), or physiological (growth factors) stimuli induce heat shock proteins. This study investigated the effect of heat shock on endotoxin-induced plasma leakage and goblet cell mucus discharge in the small intestine of rats of Sprague-Dawley (SD) and Long-Evans (LE) strains. India ink was used as the tracer to detect leaky microvessels. The mucus secretion of the goblet cells of intestinal villi was observed with scanning electron microscopy and calculated with digital morphomertric software SimplePCI. Our results showed that endotoxin-induced plasma leakage and goblet cell discharging in the two strains increased significantly as compared to rat groups receiving saline. Numerous openings on the epithelial surface of villi resulted from compound exocytosis of mucus granules in goblet cells. Either 30 min or 1h after LPS injection, heat shock pretreatment in LE rats LPS-induced plasma leakage in the duodenum and ileum was reduced by 58-80% (P<0.01). 1 h after LPS injection in LE rats pretreated with heat shock, the number of discharging goblet cells in the ileum was reduced (P<0.05). In SD rats, heat shock inhibited LPS-induced plasma leakage in the duodenum and ileum at 1h after LPS injection by 56-68% (P<0.01), and the number of discharging goblet cells was reduced in the duodenum and ileum (P<0.05). In conclusion, heat shock could protect rat intestine from endotoxin-induced inflammation and mucus secretion.

Thèse-Liège. / At head of title: Université de Liège. Faculté de médicine. Clinique oto-rhino-larynologique. Institut Léon Frédéric, Laboratoire de biochimie. "Résumé":p. 205-209. "Thèses annexes" (leaf) inserted. Bibliography: p. 210-216.

Thèse-Liège. / At head of title: Université de Liège. Faculté de médicine. Clinique oto-rhino-larynologique. Institut Léon Frédéric, Laboratoire de biochimie. "Résumé":p. 205-209. "Thèses annexes" (leaf) inserted. Bibliography: p. 210-216.

No description available.

Aujourd’hui, les pathologies respiratoires chroniques constituent un fardeau sanitaire mondial. Beaucoup sont associées à une modification rhéologique du mucus. Le rôle de clairance du mucus tapissant les voies respiratoires est de capturer des particules étrangères afin qu’enzymes et anticorps le nettoient, puis d’être transporté vers le pharynx pour être digéré ou expectoré. Dans des conditions pathologiques (e.g. mucoviscidose), les propriétés physiques assurant cette fonction vitale sont entravées par des modifications de la composition du mucus. L’objectif ici est de caractériser en profondeur les propriétés mécaniques du mucus vis-à-vis du développement d’appareils d’aide à la clairance. Ceci est réalisé par des moyens expérimentaux et de la modélisation depuis la base de données qui en découle. Le mucus réel implique de sérieuses problématiques de collecte, c’est pourquoi le choix a été fait de préparer des simulants à partir de glycoprotéines à différentes concentrations reproduisant la variété naturelle du mucus. Cela a permis de tester chacune des variétés vastement, palliant ainsi les problèmes de cohérence intrinsèque. La microscopie optique et la MEB ont donné un aperçu visuel du réseau 3D des simulants et confirmé sa similarité avec des mucus réels. La tension de surface, liée à la mouillabilité et l’adhésivité du mucus sur la surface épithéliale a été mesurée. Cela a montré une bonne concordance avec des mucus pathologiques, en particulier les concentrations élevées, en cohérence avec les observations cliniques. Le mucus est sujet aux changements de température in-vivo et peut varier de 20°C près de la bouche à 40°C en cas d... / Today, chronic respiratory pathologies constitute a worldwide health burden. Most of them are associated to a modification of the mucus rheology. The clearance role of mucus is first to trap foreign particles, so that enzymes and antibodies can start the cleaning and then to transport them towards the pharynx, to be digested or expectorated. Under disease conditions (e.g. Cystic Fibrosis), the physical properties ensuring this vital function are hindered by modifications of the mucus composition. The purpose of this thesis is then to characterize thoroughly the physical (essentially rheological) properties of mucus to improve the development of clearance helping devices using both experiments and modeling based on the subsequent database. Real mucus implies strong issues related to sample collection, hence the choice made in this work was to use mucus simulants prepared from glycoproteins at various concentrations to mimic the real mucus variety. It allowed to widely test each unique sample thus palliating the issue of intrinsic consistency. Optical microscopy and SEM were used to give a complementary insight into the 3D network of samples and confirmed the similarity with former observations made on real mucus. The surface tension (closely related to the wettability and adhesiveness of the bronchial mucus on the epithelium surface) was also measured for each concentration. It showed a good agreement with pathological mucus, especially for the high polymer concentrations. Mucus is prone to temperature variations in-vivo 20°C close to the mouth to 40°C under fever conditions. Hence thermal diffusivity, conductivity, and heat capacity were measured in this tem...