The site of action of griseofulvin, a drug which is reported to be fungistatic in nature, has been under study for some time. As yet though, there is still a great deal of uncertainty as to which observed effects are primary and which are secondary. In the study reported here, initial experiments were involved with effects of griseofulvin on oxygen uptake, in correlation with cell starvation. The effects of the drug on glucose oxidation also were studied. Definite alterations were noted in both of these areas. Further investigations were carried out, utilizing cell-free extracts and techniques for measurement of dehydrogenases, but these proved unsuccessful. Amino acid metabolism also was surveyed but no evidence of any alteration was observed. Attempts to produce protoplasts from dermatophytes were successful, and utilizing these structures, investigations into the effects of griseofulvin on cytoplasmic membrane permeability and on cell wall resynthesis, were carried out. In both cases the alterations were small and appeared to be secondary in nature. In the final study, purified cell walls of organisms grown in the presence and absence of griseofulvin, were compared on the basis of amino acid, amino sugar, and sugar content. No differences were observed in these preparations. In addition, no evidence was found to show that griseofulvin wlis incorporated into cell walls. It was concluded that griseofulvin may possibly affect the enzymes involved in the synthesis of the substrates of endogenous respiration, or the mechanisms controlling these enzymes. It was also concluded that the drug's site of action is probably on or near the cytoplasmic membrane, and by inference that the biochemical site may be in the area of purine and pyrimidine metabolism. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

No description available.

Reproduction de : Thèse d'exercice : Pharmacie : Nantes : 2009. / Bibliogr.

No description available.

Thesis (Ph. D.)--University of Wisconsin, 1966. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Reproduction de : Thèse d'exercice : Pharmacie : Nantes : 2008. / Bibliogr.

No description available.

Cell wall preparations of Trichophyton mentagrophytes were digested with chitinase following which various fractions were isolated by ultrafiltration and Sephadex gel filtration. All fractions isolated contained both polysaccharide and peptide material. A correlation was seen between those fractions capable of eliciting immediate and delayed skin reactions in sensitized guinea pigs and those capable of stimulating the ±n vitro proliferation of lymphocytes taken from sensitized guinea pigs. These immunologically active fractions also developed precipitin lines with antiserum taken from sensitized animals. Amino acid analysis of an immunologically active fraction of low molecular weight indicated that the peptide content comprised a limited array of amino acids. This fraction, found to be completely reactive immunologically (UM₂(a)), appeared to have a molecular weight in the range of 2,000-4,000 as assessed by ultrafiltration and gel filtration studies. This fraction, (UM₂(a)) was further degraded by treatment with either a combination of pronase and carboxypeptidase A or with trypsin. Peptides were separated from the carbohydrate-rich fraction by ultrafiltration. The carbohydrate-rich fraction retained the ability to induce both immediate and delayed skin reactions in sensitized guinea pigs and to stimulate the proliferation of sensitized lymphocytes in vitro. The peptide moieties retained reactivity in that they caused delayed reactions and lymphocyte proliferation but were unable to induce immediate or Arthus reactions in sensitized animals. Tryptic peptides from UM₂(a) were purified by ion exchange chromatography. A high proportion of these peptides demonstrated immunological activity at both the cellular and humoral level since they were capable of inducing delayed reactions and/or lymphocyte transformation, as well as being capable of blocking the complement fixation reaction between UM₂(a) and specific antiserum. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

Reproduction de : Thèse d'exercice : Pharmacie : Nantes : 2008. / Bibliogr.

Orientador: Angelica Zaninelli Schreiber / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-08T15:37:56Z (GMT). No. of bitstreams: 1 Correa_FernandaSimas_M.pdf: 2038543 bytes, checksum: 170a6e791e2c64d599b88b8485092a96 (MD5) Previous issue date: 2007 / Resumo: Dermatófitos do gênero Microsporum acometem preferencialmente pele e pêlos, sendo M.canis e M.gypseum as espécies mais isoladas em nosso meio. Antifúngicos tópicos e sistêmicos são indicados para o tratamento destas dermatofitoses, que é considerado mais difícil quando comparado ao de outros gêneros de fungos queratinofílicos. Deste modo, a determinação da suscetibilidade aos antifúngicos in vitro destes microrganismos é de interesse para embasamento da terapêutica empírica, avaliação de falhas terapêuticas, e testes de novos antifúngicos. No entanto, os dermatófitos não foram incluídos no documento relacionado do CLSI (M38-A, 2002). Os estudos disponíveis até o momento, utilizando conídios dos fungos, apresentam resultados muito divergentes, devido a falta de padronização e o grande número de variáveis pré-analíticas envolvidas. Em adição, uma vez que a forma de hifas predomina no tecido infectado, há controvérsias sobre o fato de se a forma conidial seria adequada para os testes. Há poucos relatos na literatura sobre avaliação dinâmica de crescimento de fungos e a taxa de inibição destes por drogas antifúngicas, mas nenhum destes realizados com dermatófitos. Este estudo se propôs a determinar condições para realização do teste de suscetibilidade pelo método de microdiluição em caldo e padronizar a avaliação de crescimento dinâmico pelo sistema BCT® para seis cepas do gênero Microsporum, determinando respectivamente CIM e CFM e taxas de inibição de crescimento frente a ciclopirox olamina, terbinafina e griseofulvina. Os resultados obtidos apontaram: ágar batata como o melhor meio de cultura para produção de conídios, inóculo de 1x 103 células/ml, incubação de 7 dias a 28ºC e leitura final considerando 100% de inibição do crescimento para o teste de microdiluição em caldo. Os resultados de CIM variaram de 1,0 a 16,0 µg/ml para ciclopirox olamina, de 0,005 a 0,004 µg/ml para terbinafina e de 2,5 a 20,0 µg/ml para griseofulvina. No Sistema Automatizado BioCell-Tracer® os testes foram realizados com: concentração de PLL de 0,05%; inóculo ? 1x106 conídios/ml em 5?l; incubação a 30ºC por 72 a 96h; 30ºC como temperatura de realização do teste e tempo total de experimento de 3 horas e 30 minutos. Todas as cepas apresentaram taxa de inibição de crescimento acima de 85% na fase de exposição à droga frente aos antifúngicos avaliados, na concentração equivalente ao resultado de CIM obtido pela técnica de microdiluição em caldo e, em pelo menos, uma diluição abaixo / Abstract: Dermatophytes of the genus Microsporum preferentially invade skin and hair, being M.canis and M.gypseum the most prevalent species in our routine. Topics and systemic antifungal agents are indicated for the treatment of theses dermatophytoses, which is considered more difficult when compared to other genera of keratinofilic fungi. By the way, the determination of in vitro antifungal susceptibility of these organisms is interesting as a guide of empiric therapy, evaluation of therapeutic failures and to evaluate new antifungal agents. However, dermatophytes were not included in the CLSI document (M38-A, 2002). The studies available until now, using fungi conidia, present divergent results due to the lack of standartization and the large number of pre-analytical variables involved. In addiction, once the hyphae forms predominate in infected tissues, there are controversies about if the conidial form would be adequate for the tests. There are few articles in the literature about dynamical evaluation of fungi growth and their growth inhibition rate in contact with antifungal agents, but none with dermatophytes. This study proposed the determination of conditions for broth microdilution susceptibility test and the standardization of dynamical growth evaluation by the BCT® system for six strains of Microsporum sp, determining respectively MIC and MFC and the inhibition rate after application of ciclopirox olamine, terbinafine and griseofulvin. The results pointed: potato dextrose agar as the best culture medium for conidium production, inoculum concentration of 1x 103 conidia/ml, incubation for 7 days at 28ºC and test enpoint at 100% of growth inhibition for broth microdilution test. The MIC results ranged from 1,0 to16,0 µg/ml for ciclopirox olamine, 0,005 to 0,004 µg/ml for terbinafine and 2,5 to 20,0 µg/ml for griseofulvin. On the automatizated system BioCell-Tracer®, the tests were realized with: PLL concentration of 0,05%; inocula of ? 1x106 conídia/ml in 5?l; incubation at 30ºC for 72 to 96hand also 30ºC as the test temperature, 3 hours and 30 minutes as total time of experiment. All strains showed growth inhibition rate above 85% on drug exposure phase against the antifungal agents evaluated, in MIC obtained by both microdilution method and, at least, one dilution below / Mestrado / Patologia Clinica / Mestre em Ciências Médicas