Orientador: Jose Pedrazzoli Junior / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-09T20:11:33Z (GMT). No. of bitstreams: 1 Godoy_AnitaPaulaOrtizde_D.pdf: 3223773 bytes, checksum: d3b817672fc43b5a748a32618eda5fe4 (MD5) Previous issue date: 2007 / Resumo: A maioria dos isolados de H. pylori é sempre susceptíveis à amoxicilina, um antibiótico comumente usado na terapia de erradicação do H. pylori. Entretanto, a resistência à amoxicilina é emergente nos isolados clínicos, especialmente em paises onde esse antibiótico pode ser obtido sem prescrição. Assim, o mecanismo molecular de resistência a amoxicilina tem sido apenas identificada em poucas H. pylori AmoxR e tolerantes. Este trabalho analisou os genes que atualmente apresentam maior probabilidade de estarem envolvidos no mecanismo de resistência e também a expressão gênica diferencial de uma linhagem resistente à amoxicilina crescida em presença e ausência da droga. Depois de realizada a transformação com o DNA genômico, foi feito também a transformação natural, da linhagem susceptível 26695 com os genes, previamente amplificados por PCR, pbp1A, pbp2, ftsI (pbp3), pbp4, hcpA, lytB, rodA1, mreC, mreB, e llm, dos isolados clínicos resistentes. Apenas a transformação realizada com o gene pbp1A resultou em colônias amoxR de todos os sete isolados clínicos estudados. A resistência foi mediada por várias alterações mutacionais no segundo e terceiro motif conservado de PBP1A e suas adjacências. Todos os 8 transformantes AmoxR analisados continham uma substituição T555R e N542Y, sete dos transformantes AmoxR apresentavam a substituição S402G, E406A, e S417T, enquanto que um transformante tinha apenas a substituição S414R. Entretanto não podemos excluir a relação de outros genes a essa resistência. Para avaliar se a resistência da linhagem Hardenberg apresenta uma expressão gênica diferencial quando entra em contato com a amoxicilina, foi realizada a técnica de RAP ¿ PCR. Foram usados 5 diferentes pares de primers arbitrários que geraram 101 bandas com expressão diferencial. Nossos resultados mostraram que a amoxicilina altera a expressão de genes envolvidos na adaptação da bactéria a nova situação. Neste sentido, os resultados que foram obtidos com este trabalho poderão contribuir para a caracterização molecular dos mecanismos de resistência das linhagens brasileiras de H. pylori à amoxicilina, droga essa usada na terapia de erradicação / Abstract: Amoxicillin-based therapies are highly effective for the treatment of Helicobacter pylori infections, but the efficacy may decrease as the incidence of amoxicillin resistance is increasing. The extensive use and limited choice of the antibiotics have resulted in the development of antibiotic resistance in H. pylori. So far, the molecular mechanism underlying stable amoxicillin resistance has only been identified for a few naturally occurring amoxicillin-resistant (AmxR) In this study, we evaluated genes were selected as potential candidates for to be responsible to amoxicillin resistance and we evaluated the gene expression pattern in response to amoxicillin. No changes of genes ftsI, hcpA, llm, lytB, mreB, mreC, pbp2, pbp4, and rodA1, encoding putative PBPs or involved in cell wall synthesis were found among the transformed resistant H. pylori. Amoxicillin resistance was mediated by various mutational changes in or adjacent to the second and third PBP-motifs of the pbp1A gene. All eight AmxR transformants analyzed contained a T555S and N561Y substitution, seven of the AmxR transformants contained a S402G, E406A, and S417T substitution, while one transformant only contained a S414R substitution. Although we cannot exclude the role of other genes in amoxicillin resistance. For to evaluate the gene expression was using RNA arbitrarily primed PCR (RAP-PCR). In the experiments, c. 101 differentially expressed RAP-PCR products were identified using five arbitrary primers. The differential expression of the isolated cDNAs was confirmed by real-time PCR. The results showed that amoxicillin alters the expression of cDNAs. Further analysis of these cDNAs will allow a better comprehension of both the molecular mechanism(s) of amoxicillin resistance and the adaptative mechanism (s) used by H. pylori in the presence of this antibiotic / Doutorado / Doutor em Farmacologia

Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Veronika Řepová Supervisor: Prof. PharmDr. Petr Pávek, Ph.D., Prof. Ramiro Jover Atienza, Ph.D. Title of diploma thesis: Alterations in gene expression of hepatobiliary transporters as potential mechanisms for drug-induced cholestasis by amoxicillin and clavulanic acid The combination of amoxicillin and clavulanic acid (AMO/CLA) represents one of the most frequent causes of the idiosyncratic type of drug-induced liver injury (DILI) nowadays. Despite difficulties in diagnosis and causality assessment, the clinical features have already been reported and in most of the cases categorized as cholestatic damages. Number of descriptions of the molecular mechanisms of drug-induced cholestasis has been rising recently and the role of hepatobiliary transporters has turned out to be crucial in the pathogenesis. However, the mechanisms of AMO/CLA-induced DILI at the molecular level still remain indistinct. In order to investigate the hepatotoxic effects of AMO/CLA and AMO alone in vitro, HepG2 and human Upcyte hepatocytes were used as hepatocellular models. The mRNA levels of key bile acid (BA) transporters, enzymes and nuclear receptors (NRs) were measured by quantitative real-time polymerase chain...

Helicobacter pylori (hereinafter referred to as H. pylori) is a gram-negative bacteria which colonises the human stomach mucosa. Its role in the aethiopathogenesis of chronic gastritis, ulcer disorders of the gastroduodenum and MALT-lymphoma has been clearly demonstrated, and in connection with the occurrence of stomach cancer it has been indicated by the World Health Organisation (WHO) as a class I carcinogen. H. pylori infection can be detected from samples of stomach mucosa taken in an endoscopic examination (rapid urease test, microscopic examination, culture), or the non-invasive method can be used (13 C-Urea Breath Test or H. Pylori stool antigen test - HpSA). Effective therapy of H. pylori infection resides in the administration of a combination of antibiotics and a proton pump inhibitor. In recent years the resistance of bacterial strains to used antibiotics has been increasing on a worldwide scale, and we can also observe this trend in the case of H. pylori. If the level of resistance exceeds 20 % for clarithromycin and 40 % for metronidazole, these antibiotics are not recommended for the treatment of an infection caused by this bacteria. In a group of 61 patients at the Department of Internal Medicine at the University Hospital Motol who had undergone an endoscopic examination of the...