Campylobacter are a leading cause of bacterial derived foodborne illness. Thymol is a natural product that reduces survivability of Campylobacter in vitro. Results from animal studies, however, indicate that absorption or degradation within the stomach and small intestine may preclude delivery of thymol to the cecum and large intestine, the main sites of Campylobacter colonization. Presently, we compared the anti- Campylobacter activity of thymol against that of thymol-β-D-glucopyranoside (β-Dthymol), the latter suspected to be resistant to degradation and absorption in the proximal alimentary tract lacking β-glycosidase activity. When treated with 1 mM thymol, the survivability of Campylobacter coli and jejuni in vitro was reduced by 3.41 to 6.87 log_10 CFU mL-1 after 48-h pure culture and after co-culture, respectively. In the presence of a β-glycosidase-expressing Parabacteroides distasonis. Conversely, the survivability of C. coli and C. jejuni was reduced by 3.72 and 4.30 log_10 CFU mL-1, respectively, in cocultures treated with β-D-thymol, but not in pure cultures similarly treated. When tested in mixed cultures of porcine or bovine fecal microbes possessing endogenous β- glycosidase, C. coli and C. jejuni survivability was reduced by 3.26 and 2.50 log_10 CFU mL-1, respectively, whether treated with thymol or β-D-thymol. In mixed populations of avian crop and cecal microbes, C. jejuni survivability was reduced 1.41 to 2.32 log_10 CFU mL-1 whether treated with thymol or β-D-thymol. Thymol and β-D-thymol inhibited ammonia accumulation in mixed populations of porcine and mixed bovine fecal microbes which is consistent with free thymol’s purported role as a deaminase inhibitor. Conversely, thymol and β-D-thymol did not affect ammonia accumulation in mixed populations of avian gut microbes implicating population specific effects of these compounds. β-D-thymol, but not thymol, reduced accumulation of fermentation acids indicating the conjugate inhibited fermentation which may limit its application to the last meal or last few meals before harvest. Oral administration of 150 μmol β-D-thymol reduced C. jejuni in avian crop, but not in cecal contents; treatment with thymol was ineffective. These results indicate that β-D-thymol, or similar β-glycosides, may be a suitable candidate to escape absorption and degradation within the proximal alimentary and retain its anti-Campylobacter properties. Further research is needed to reduce such technology to practice.

La production d'aluminium est une industrie importante au Québec. Les propriétés de ce métal le vouent à de multiples usages présents et futurs dans le cadre d'une économie moderne durable. Toutefois, le procédé Hall-Héroult est très énergivore et des progrès demeurent donc nécessaires pour en diminuer les coûts financiers et environnementaux. Parmi les améliorations envisageables de la cellule d'électrolyse se trouve le contact entre la cathode et la barre collectrice, qui doit offrir une faible résistivité au passage du courant électrique. En cours d'opération de la cellule, ce contact a tendance à se dégrader, générant des pertes énergétiques significatives. Les causes de cette dégradation, pouvant provenir de phénomènes chimiques, thermiques, mécaniques et/ou électriques, demeurent mal comprises. Le but du présent projet était donc d'étudier les phénomènes chimiques se produisant au contact bloc-barre de la cellule d'électrolyse Hall-Héroult. En premier lieu, un aspect crucial à considérer est la pénétration du bain électrolytique dans la cathode, car des composés de bain atteignent éventuellement la barre collectrice et peuvent y réagir. À cet effet, une méthode novatrice a été développée afin d'étudier les cathodes et la pénétration du bain dans celles-ci à l'aide de la microtomographie à rayons X. Cette méthode rapide et efficace s'est avérée fort utile dans le projet et à un potentiel important pour l'étude future des cathodes et des phénomènes qui s'y produisent. Ensuite, une cellule d'électrolyse rectangulaire à petite échelle a été développée. Plusieurs phénomènes observés en industrie sur des autopsies de cellules post-opération et rapportés dans la littérature ont été reproduis avec succès à l'aide de cette cellule expérimentale. Puis, des tests sans électrolyse, ciblant l'effet du bain électrolytique sur l'acier, ont aussi été conçus et complétés afin de ségréger l'influence des différents paramètres en jeu. L'analyse des résultats de l'ensemble de ces tests a permis de constater différents phénomènes au contact bloc-barre, dont la présence systématique de NaF et, surtout, de béta-Al[indice inférieur 2]O[indice inférieur 3]. Outre la carburation inévitable de la barre collectrice, la formation d'une couche Fe-Al a aussi été observée, favorisée par une pénétration rapide du bain électrolytique dans la cathode ainsi que par une composition de bain acide en surface de la barre. Cette couche comportait par ailleurs des cristaux de béta-Al[indice inférieur 2]O[indice inférieur 3] pouvant nuire à sa conductivité électrique. Ensuite, à des ratios de bain entre 2.5 et 4.9, une mince couche contenant les éléments Al et N peut se former en surface de la barre. Pour un bain tres basique (> 6.0), c'est plutôt une couche Na [indice inférieur 2] O qui a été observée. En conditions d'électrolyse mais sans une pénétration rapide du bain dans la cathode, du Na a pu carrément pénétrer dans la barre collectrice, préférentiellement avec le carbone. De plus, de la corrosion ainsi que des couches de fer et d'oxyde de fer peuvent se former sur la barre et potentiellement dégrader la qualité du contact électrique. \Pour la suite des travaux, des mesures de résistivité ainsi que l'analyse des échantillons industriels permettraient d'évaluer l'impact de ces phénomènes sur la qualité du contact.

No description available.

PhD / The aims of this study were to test the efficacy of immunoglobulin and its Fab and Fc fragment in the treatment of experimental autoimmune neuritis (EAN) in Lewis rats, to investigate which portion of immunoglobulin is operative in the effect of IVIg, and to clarify the possible mechanisms by which immunoglobulin exerts its action in the treatment of rats EAN. EAN was induced by immunization with whole bovine peripheral nerve myelin. The immunized rats were randomized into groups, assessed clinically, electrophysiologically, and histologically, and intravenously injected with normal saline, albumin, human IVIg preparation, purified Fab or Fc fragments. The treatment efficacy was compared between normal saline and albumin groups, albumin and IVIg groups, albumin and Fab groups, albumin and Fc groups, Fab and Fc groups, Fab and IVIg groups, and Fc and IVIg groups. Methods of myelin isolation, antibody purification, and Western blot techniques were also applied. The results revealed that treatment with Fc fragment and IVIg at the onset of signs of disease effectively prevented further progression of disease, shortened disease duration, and facilitating recovery from illness as shown in clinical, electrophysiological and histological parameters. In the study which the efficacy of albumin and IVIg was compared, 5 out of 17 rats (29%) in the albumin group and 12 out of 17 (71%) in the IVIg group completely recovered from the clinical disease by day 30. The animals receiving IVIg treatment exhibited lower clinical scores, less prolongation of S wave latencies, better maintained S wave amplitudes, less reduction of distal motor NCVs, better maintained distal and proximal CMAP amplitudes, and lower histological grades. In the study which the efficacy of albumin, Fab fragment, Fc fragment, and IVIg was compared, 0 out of 8 (0%) in the albumin group, 1 out of 8 (13%) in the Fab group, 4 out of 8 (50%) in the Fc group, and 6 out of 9 (67%) rats in the IgG group completely recovered from the clinical disease by day 30. The animals receiving Fc fragment and IVIg treatment exhibited lower clinical scores, less prominent weight loss, less prolongation of S wave latencies, better maintained S wave amplitudes, less reduction of distal motor NCVs, better maintained distal and proximal CMAP amplitudes, and lower histological grades.

Stuttgart, FH, Diplomarb., 2002.

Universiẗat, Diss., 2006--Mainz.

No description available.

No description available.

Orientador: Leonilda Maria Barbosa dos Santos / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-07T03:41:32Z (GMT). No. of bitstreams: 1 Castro_FabianoRobertode_M.pdf: 943470 bytes, checksum: 271c21deb3b25015f9737d33adf49814 (MD5) Previous issue date: 2006 / Resumo: A Síndrome de Guillain-Barré (SGB) é uma doença desmielinizante do sistema nervoso periférico (SNP). Baseado principalmente nas similaridades clínicas e histopatológicas a Neurite Experimental Auto-imune (EAN) tem sido extensivamente usada como modelo de estudo da SGB. A EAN é uma doença auto-imune, que pode ser experimentalmente induzida em ratos geneticamente suscetíveis através da imunização com os componentes da mielina de nervos periféricos tais como os peptídeos P0 e P2 , ou ainda por transferência adotiva de lifócitos T CD4+ do tipo Th1. Diferentes tentativas de tratamentos para a SGB têm sido estudadas, dentre elas pode-se citar a plasmaferese, o uso de anticorpos monoclonais, administração de corticóides e a imunossupressão global através da administração de intérferon ß. A utilização de venenos totais de serpentes, ou frações deles, já demonstrou bons resultados na tentativa de tratamento de alguns modelos de doenças auto-imunes como a diabetes auto-imune insulino dependente, lúpus e encefalomielite experimental auto-imune (EAE). No presente trabalho foi estudado o efeito de uma fração do veneno da cascavel sul americana Crotalus durissus terrificus (Cdt), a crotapotina, no modelo de EAN. São apresentadas evidências de que tanto a administração intraperitoneal (IP) como a oral de crotapotina reduz significativamente a gravidade da EAN induzida em ratos Lewis, associada a um significativo declínio na resposta proliferativa das células T neuritogênicas, assim como diminuição de infiltrados de células mononucleares no nervo ciático dos os animais / Abstract: Biomedical research in which venom components are being investigated for their potential as novel therapeutic agents has emerged as an interesting option. Crotapotin which is a fraction of the venom of the rattlesnake Crotalus durissus terrificus, has been described as an antinflammatory that acts on the innate arm of the immune response. Here we have demonstrated that intraperitoneal (IP), as well as oral administration of crotapotin significantly reduces the severity of experimental autoimmune neuritis (EAN), an experimental model for Guillain-Barré Syndrome. The reduction of the severity of the disease is associated with a reduction in the mononuclear cells infiltrating in the sciatic nerve and a significant decrease in the lymphocyte proliferative response to neuritogenic peptide / Mestrado / Ciencias Basicas / Mestre em Clinica Medica

Orientadores: Alessandro dos Santos Farias, Leonilda Maria Barbosa dos Santos / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-23T01:58:27Z (GMT). No. of bitstreams: 1 Pradella_Fernando_M.pdf: 4468527 bytes, checksum: 63d6760bd0ea06c5fcab94d1421da291 (MD5) Previous issue date: 2013 / Resumo: O resumo poderá ser visualizado no texto completo da tese digital / Abstract: The abstract is available with the full electronic document / Mestrado / Imunologia / Mestre em Genética e Biologia Molecular