Made available in DSpace on 2016-04-28T20:16:25Z (GMT). No. of bitstreams: 1 2007- Luiz Figueira Pinto.pdf: 1581116 bytes, checksum: 36931ba33454d8c934e6419c55b06974 (MD5) Previous issue date: 2007-12-13 / Palicourea marcgravii (Pm) is the most important toxic plant in Brazil. It is responsible for about half of all bovine deaths by natural poisoning in the country. The poisoning has a hyperacute evolution resulting in sudden death, which is attributed to the monofluoroacetic acid. This substance has high toxicity to several mammals, including humans. The homeopathic therapeutics uses ultra-highly diluted and dynamized solutions and there is enough evidence to investigate them as possible protection against poisonings. The aims of the present work were to compare the toxic effects of aqueous (AE) and hydroalcoholic (mother tincture - MT) extracts of Pm in rats, evaluate the effects of ultra-highly diluted and dynamized solutions (Pm 6CH and Pm 30CH) over the development of tolerance to the toxic effects of Pm and evaluate clinical, necroscopic and histopathological alterations in nonintoxicated rats treated with these solutions. AE and MT groups were formed of 10 animals each which received the extract in doses of 0.4g/kg, 0.8g/kg, 2g/kg and 4g/kg, intragastrically. The UD6EA and UD30EA groups were formed of five rats each, which received respectively 1 mL of Pm 6CH e Pm 30CH solutions, by oral route, three times a day, for eight days. Then, they were intoxicated with 2g/kg of Pm aqueous extract, intragastrically and received the correspondent ultra-highly diluted and dynamized preparations hourly until death. The UD6 and UD30 groups were formed of five rats each and received respectively 1 mL of Pm 6CH and Pm 30CH, orally, three times a day for 63 days. The animals were evaluated using clinical parameters, including the direct observation of their behavior at the open field and at the elevated plus-maze, and the study of the macro and microscopic lesions. Hyperacute death occurred after administration of the doses of 0.4g/kg, 0.8g/kg, 2g/kg e 4g/kg. In the AE group, prostration and nervous hyperexcitability followed or not by convulsive crisis were observed. In the MT group, the animals presented marked nervous depression without convulsion. Hepatic congestion and evidence of cardiac dilation were observed in the necropsy. Hydropic vacuolar degeneration of the renal distal convoluted tubules and congestion of several organs were observed in the histopathological examination. The latencies for the emergence of the first clinical signs, the convulsions and death occurrence were different in the animals of groups AE1 (Pm 2g/kg), UD6EA and UD30EA, but was considered inadequate the animals amount. Groups UD6 and UD30 did not show any clinical, behavioral, necroscopical or histopathological differences when compared to the control group. The conclusions were that the aqueous extract causes nervous excitability and convulsions while the mother tincture causes nervous depression. There is cumulative effect of the toxic substances present in the plant, and there is not evidence that the ultra-highly diluted and dynamized preparation increases the tolerance to Pm intoxication. / A Palicourea marcgravii (Pm), a planta t?xica mais importante no Brasil, ? respons?vel por cerca da metade das mortes por intoxica??o natural em bovinos no Pa?s. A intoxica??o cursa com evolu??o superaguda e morte s?bita, atribu?da ao ?cido monofluoroac?tico, subst?ncia de alta toxidez para diversos mam?feros, inclusive o homem. A terap?utica homeop?tica emprega solu??es ultradilu?das e dinamizadas e h? evid?ncias suficientes para explor?-la como poss?vel prote??o contra intoxica??es. Os objetivos deste trabalho foram comparar os efeitos t?xicos dos extratos aquoso (EA) e hidro-alco?lico (tintura-m?e - TM) de Pm em ratos e avaliar o efeito das solu??es ultradilu?das e dinamizadas (Pm 6CH e Pm 30CH) sobre a toler?ncia e a??o t?xica da planta e avaliar a ocorr?ncia de altera??es cl?nicas, necrosc?picas e histopatol?gicas em ratos n?o-intoxicados tratados com essas solu??es. O EA, a TM, a Pm 6CH e a Pm 30CH foram administrados a 49 ratos distribu?dos em seis grupos-teste; dois grupos adicionais foram mantidos como controle. Os grupos EA e TM foram constitu?dos por 10 animais cada, que receberam doses que variaram de 0,4g/kg, 0,8g/kg, 2g/kg e 4g/kg. Os grupos UD6EA e UD30EA foram constitu?dos por cinco ratos cada e receberam 1mL das solu??es Pm 6CH e Pm 30CH, respectivamente, por via oral, tr?s vezes ao dia, e ap?s oito dias 2g/kg do extrato aquoso de Pm, por via intrag?strica. Os grupos UD6 e UD30, constitu?dos por cinco ratos cada, receberam 1mL de Pm 6CH e Pm 30CH, respectivamente, por via oral, tr?s vezes ao dia, durante 63 dias. Os animais foram avaliados por par?metros cl?nicos, comportamentais (campo aberto e labirinto em cruz elevado), achados de necropsia e exames histopatol?gicos. Ocorreu morte superaguda com as doses de 0,4g/kg, 0,8g/kg, 2g/kg e 4g/kg. No grupo EA observaram-se prostra??o e hiperexcitabilidade nervosa, seguida, ou n?o, por crise convulsiva e no grupo TM depress?o nervosa acentuada, sem convuls?o. Havia ainda p?los eri?ados, dispn?ia, cianose de extremidades, e hipotermia. ? necropsia observaram-se f?gado congesto e dilata??o card?aca e pelo exame histopatol?gico, degenera??o hidr?picovacuolar em t?bulos contornados distais dos rins e congest?o em v?rios ?rg?os. Houve diferen?as nas lat?ncias para o aparecimento dos primeiros sinais cl?nicos, de convuls?o e ocorr?ncia de morte entres os grupos UD30EA, UD6EA e EA1 (Pm 2g/kg), mas o numero de animais foi considerado pequeno para se atribuir efeito protetor das solu??es ultradilu?das e dinamizadas ? intoxica??o pela planta. Os grupos UD6 e UD30 n?o apresentaram diferen?as cl?nicas, comportamentais ou necrosc?picas em compara??o com o grupo controle. Conclui-se que o extrato aquoso produz excitabilidade nervosa e convuls?o e a tintura-m?e depress?o nervosa, que h? efeito acumulativo e que as solu??es ultradilu?das e dinamizadas n?o induziram aumento ponderal da toler?ncia aos efeitos t?xicos da Pm e n?o produziram altera??es no estado de sa?de dos animais sadios.

Depuis plusieurs années, les constructeurs automobiles suivent la voie du « downsizing » pour le développement des moteurs à allumage commandé. Ce procédé basé sur la réduction des cylindrées moteur combinée à la suralimentation a déjà fait ses preuves quant à son intérêt dans l’augmentation du rendement et la réduction des émissions polluantes des moteurs à essence. Les nouvelles conditions thermodynamiques, de turbulence et de dilution de ces moteurs engendrant de nouvelles possibilités de dilution dans les mélanges air/carburant, elles amènent également de nouvelles problématiques quant aux combustions anormales observées et l’apparition d’importantes variabilités cycliques. Ces travaux de thèse s’insèrent dans l’objectif de compréhension du comportement des flammes de prémélange d’isooctane/air en expansion dans des conditions représentatives d’un moteur « downsizé ». Leur étude a dans un premier temps été réalisée dans des conditions laminaires afin d’extraire les vitesses de flammes et longueurs de Markstein associées aux différents mélanges réactifs, et notamment sous forte dilution. Des corrélations ont alors été développées pour répondre aux besoins des modèles de simulation. Un nouveau dispositif de diagnostic optique a ensuite été employé pour améliorer la visualisation des flammes turbulentes en expansion. Une corrélation de coefficient correctif est ici développée pour remédier à la surestimation de vitesse engendrée par une visualisation Schlieren de ces flammes turbulentes. Une étude approfondie de l’influence des conditions thermodynamiques initiales, de la turbulence, ainsi que des caractéristiques diffusives du mélange air/carburant a par ailleurs été conduite afin d’isoler l’effet de chacun de ces paramètres sur le développement et la propagation de la flamme turbulente. Enfin l’effet d’une évolution simultanée des conditions thermodynamiques initiales similaire à celle d’une compression moteur a été étudié pour mieux appréhender les changements de comportement des flammes turbulentes dans des conditions plus représentatives du moteur à allumage commandé. / For several years, “downsizing” is used by car manufacturers to develop new spark ignition engines. This method based on the reduction of engine size combined with an increase of intake pressure (turbocharger) is well known to reduce pollutant emissions and increase efficiency. New thermodynamic, turbulent and dilution conditions could be used with these new engines but they can bring new issues like unusual combustion or cyclic variability. This thesis took place to improve the understanding of premixed expanding isooctane/air flames behavior under downsized engine-like conditions. As a first step, this work is conducted under laminar conditions to extract laminar burning velocities and Markstein lengths of the different mixtures, especially under high dilution. New correlations are then developed to answer the needs of numerical models. A new optical dispositive is then used to improve the visualization of turbulent expanding flames. A corrective coefficient correlation is proposed to avoid the overestimated values of turbulent burning speed generated by Schlieren visualization with such turbulent flames. A deep survey of starting conditions (temperature, pressure, turbulence, dissipative characteristics of air/fuel mixtures) influence is done to investigate the effect of each parameters on the development and the propagation of the turbulent flame. Finally, the effect of a coupled rise of initial temperature and pressure, similar to an engine compression, is studied to better understand the changes of flame behavior under more realistic spark-ignition engine conditions.