The objective of this diploma thesis was to determine the influence of the application of 5-aminosalicylic acid (5-ASA) in the peritoneal cavity on the initiation and course of the inflammatory reaction. For these purposes, the rat was chosen as the model animal on which the model of intraperitoneal lavage was applied. The rat’s peritoneal cavity is easily accessible and reflects the functions and reactions of the immune system. For the purposes of the experiment, the rats were divided into 3 groups; in the first group, the peritoneal cavity was assessed in its physiological condition, without any prior application of the substance. PBS was applied to the second group of rats, and the evaluation of the absolute numbers of cells followed after 4 and 24 hours using the Bürker counting chamber and optical microscopy. In the last group, mesalazine was applied, the exposure of which was 4 hours for one half of the group and 24 hours for the other. These time intervals were followed by the evaluation of the absolute number of cells. In order to determine the differential numbers of cells for all the samples, the coated glasses were coloured and evaluated. The greatest statistically relevant difference was identified in the case of the neutrophil population, where the neutrophil share increased from 0-5 % in the intact cavity to up to 35 % in the cavity after the PBS application. Out of all the experimental groups, the population of lymphocytes was relatively stable; the share of macrophages was, statistically, considerably lower for the groups after the mesalazine application. These results indicate that the application of PBS as an inert substance did not cause such a major reaction regarding the influx of neutrophils as the application of 5-ASA.

IN ENGLISH Drug dependency in inflammatory bowel disease (IBD), Crohn's disease (CD) and ulcerative colitis (UC), is a specific disease phenotype which determines disease prognosis and hence may be used as a prognostic marker for treatment management. Drug dependency in IBD has been well described in corticosteroid treatment and recently also in infliximab (IFX) therapy. The aims of this thesis were: 1) to assess the occurrence of IFX dependency in paediatric and adult patients with CD; further to search for clinical and genetic predictors of IFX outcome and to evaluate the impact of IFX dependency on surgical rate; 2) to assess in CD patients the outcome of the first course of 5-ASA monotherapy with emphasis on 5-ASA dependency and to define clinical predictors of 5-ASA treatment outcome. We found that 66% of children and 29% of adults with CD became IFX dependent. The high frequency in paediatrics is in agreement with previously published studies, while the finding in adult patients indicates a lower rate of IFX dependency in the only study to date. Perianal disease and no bowel surgery prior to IFX start were predicative of IFX dependency in paediatric patients. In adult cohort, 2 genetic variants LTA c.207 A>G and CASP9 c.93 C>T were associated with IFX outcome, whereas no relevant clinical...

IN ENGLISH Drug dependency in inflammatory bowel disease (IBD), Crohn's disease (CD) and ulcerative colitis (UC), is a specific disease phenotype which determines disease prognosis and hence may be used as a prognostic marker for treatment management. Drug dependency in IBD has been well described in corticosteroid treatment and recently also in infliximab (IFX) therapy. The aims of this thesis were: 1) to assess the occurrence of IFX dependency in paediatric and adult patients with CD; further to search for clinical and genetic predictors of IFX outcome and to evaluate the impact of IFX dependency on surgical rate; 2) to assess in CD patients the outcome of the first course of 5-ASA monotherapy with emphasis on 5-ASA dependency and to define clinical predictors of 5-ASA treatment outcome. We found that 66% of children and 29% of adults with CD became IFX dependent. The high frequency in paediatrics is in agreement with previously published studies, while the finding in adult patients indicates a lower rate of IFX dependency in the only study to date. Perianal disease and no bowel surgery prior to IFX start were predicative of IFX dependency in paediatric patients. In adult cohort, 2 genetic variants LTA c.207 A>G and CASP9 c.93 C>T were associated with IFX outcome, whereas no relevant clinical...