Thesis (Ph.D.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / The present view of the lipid metabolism of tumors appears to be, as stated by Gore and Popjak (32) and Gore (11), that tumors in general lack the capacity to utilize acetate for the biosynthesis of lipids. The results of Medes et al. (12), Busch (13), and Busch and Baltrush (14), lend support to the view expressed by Gore and Popjak. However, evidence to the contrary, namely that the lipid metabolism in tumors is not impaired, also exists. In this regard the results of Trew and Begg (16), Jablonski and Olson (17), Olson et al. (54), and Haven (19,20) are of special significance. The lack of agreement in the results of various investigators was attributed by Henderson and LePage (15) to differences between the tumors studied, but it was felt that the discrepancies in the results could also be attributed to differences in the conditions of incubation, the importance of which was emphasized by Busch (27) [TRUNCATED]. / 2031-01-01

Submitted by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2016-03-29T14:51:59Z No. of bitstreams: 1 arquivototal.pdf: 2889280 bytes, checksum: 9c7ca34cb774b831c8a33f50c09aee7f (MD5) / Made available in DSpace on 2016-03-29T14:51:59Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2889280 bytes, checksum: 9c7ca34cb774b831c8a33f50c09aee7f (MD5) Previous issue date: 2015-02-26 / Nanomedicine is the use of nanomaterials in developing new therapeutic and diagnostic procedures. However, despite the advantages and different applications of nanoparticles, they also have potential toxic effects that should be properly assessed before use. Metal oxides and, in particular, metal oxide nanoparticles have many applications. Among them, cerium oxide nanoparticles and zinc oxide have shown different pharmacological activities, both alone, and in combination with each other. Cancer is a complex genetic disease which is a major public health problem worldwide, one of the leading causes of death in Brazil. This study aimed to evaluate the toxicity and antitumor activity in vivo of cerium oxide nanoparticles and zinc oxide association (NCZ). Initially it was evaluated the acute preclinical toxicity orally with estimated NCZ LD50 above 2000 mg/kg, therefore, the sample is considered to have low toxicity in our experimental conditions. Subsequently it was performed the evaluation of repeated doses toxicity study (28 days) of NCZ by oral route. The treatment resulted in a significant decrease in the consumption of water and feed, significant increase in enzyme activity of ALT and AST, significant decrease of urea, significant increase in the total white blood cell count, significant decrease in thymus index, significantly increased of ambulation and a decrease in time of self-cleaning and withdrawals. The study of acute toxicity by intraperitoneal route, the LD50 of NCZ was estimated at about 300 mg/kg enabling the choice of doses to be used in the study of antitumor activity. NCZ showed significant antitumor activity in Ehrlich ascites carcinoma model (EAC) at doses of 10, 20 and 40 mg/kg, considering the mass, tumor volume and total cell parameters. In the investigation of its mechanism of action was observed that NCZ increased the percentage of cells in sub-G1 phase, decreased microvessel peritoneal vascular, as well promoted an increased in the concentration of IL-1, IL-10, TNF- and IFN-. It was also evaluated the toxicity of NCZ in animals with EAC submitted to antitumor treatment for nine days. It was observed a significant decrease in feed intake, significant increase in ALT activity, significant decrease in serum urea concentration, significant increase in serum creatinine and significant increase in the mean corpuscular hemoglobin. According to the results, we can infer that NCZ has low toxicity and significant antitumor activity in vivo with mechanism of action probably related to interference with the progression of the cell cycle, inducing apoptosis, increased immune response and antiangiogenic action. / A nanomedicina consiste na utilização de nanomateriais no desenvolvimento de novas modalidades terapêuticas e de diagnóstico. Todavia, apesar das vantagens e diferentes aplicações das nanopartículas, estas também possuem potenciais efeitos tóxicos que devem ser devidamente avaliados antes de sua utilização. Óxidos de metais e, em especial, nanopartículas de óxido de metais possuem várias aplicações. Dentre eles o óxido de zinco e nanopartículas de óxido de cério já demonstraram diversas atividades farmacológicas tanto de forma isolada, quanto em associação entre si. Especialmente para nanopartículas de óxido de cério, vários estudos mostram seu potencial antitumoral. O câncer é uma doença genética complexa que constitui um importante problema de saúde pública em todo mundo, sendo uma das principais causas de morte no Brasil. Esse trabalho teve como objetivo avaliar a toxicidade e atividade antitumoral in vivo de nanopartículas de óxido de cério associadas ao óxido de zinco (NCZ). Inicialmente foi avaliada a toxicidade pré-clínica aguda, por via oral, com estimativa de DL50 para NCZ acima de 2000 mg/kg sendo, portanto, a amostra considerada de baixa toxicidade nas condições experimentais avaliadas. Em seguida foi realizada a avaliação da toxicidade pré-clínica de doses repetidas (28 dias) de NCZ, por via oral. O tratamento resultou em diminuição significativa no consumo de água e ração, ureia, índice do timo e tempo de auto-limpeza e levantamentos, assim como resultou em um aumento significativo na atividade enzimática de ALT e AST, contagem total de leucócitos e ambulação. No estudo de toxicidade aguda por via intraperitoneal de NCZ a DL50 foi estimada em torno de 300 mg/kg possibilitando a escolha das doses a serem utilizadas no estudo de atividade antitumoral. NCZ apresentou significante atividade antitumoral em modelo de Carcinoma Ascítico de Ehrlich (CAE) nas doses de 10, 20 e 40 mg/kg, considerando os parâmetros massa e volume tumoral, bem como total celular. Na investigação de seu mecanismo de ação foi observado que NCZ aumentou a percentagem de células na fase sub-G1, reduziu a microdensidade vascular peritoneal, bem como aumentou a concentração de IL-1, IL-10, TNF- e IFN-. Foi avaliada ainda, a toxicidade de NCZ nos animais com CAE submetidos ao tratamento antitumoral de nove dias, sendo observada uma diminuição significativa no consumo de ração e na concentração sérica de ureia, assim como resultou em aumento significativo na atividade da ALT, concentração sérica de creatinina e hemoglobina corpuscular média. De acordo com os resultados obtidos, é possível inferir que NCZ apresenta baixa toxicidade e significante atividade antitumoral in vivo com mecanismo de ação provavelmente relacionado a uma interferência na progressão do ciclo celular com indução de apoptose, aumento da resposta imune antitumoral e ação antiangiogênica.