Targeted vs. standard treatment against Helicobacter pylori: safety assessment clinical trial

Helicobacter pylori (H. pylori) is a gram negative bacteria that represents a considerable global burden in the world and is related to many gastrointestinal diseases (peptic ulcer, gastric MALT lymphoma or gastric cancer). Currently the triple standard therapy is less used as there is an increase of the clarithromycin resistance. Therefore patients have to receive several lines of treatment with the consequence of adverse events and the possibility to interrupt the treatment. This is why the main objective is to determine if making a culture and antibiogram to do a targeted treatment cause less adverse events with the same eradication than making an empirical treatment to eradicate H. pylori. The secondary objective is to determine the prevalence of resistance to clarithromycin in the province of GironaThis is a multicentre clinical trial without blinding; patients are selected by non-probabilistic sampling, with a total sample of 868 patients randomized in two equal groups of 434 patients in each group. The study will last 2 years. The endpoints will be to evaluate the adverse events and eradication of each group of patients. Also it will be evaluated the resistance to clarithromycin

Transferència d’electrò i protó als intermediaris de reacció de les hemo-catalases

Projecte de recerca elaborat a partir d’una estada a l’University of Pennsylvania, EUA, entre els mesos d’agosta a desembre del 2006. Les hemo-catalases són enzims que protegeixen les cèl•lules dels efectes tòxics del peròxid d'hidrogen. Aquesta reacció té lloc en dues etapes, via l'intermediari Compost I (Cpd I). Tanmateix, el Compost I pot seguir una reacció secundària, a través de l'intermediari Compost II. Hi ha dos tipus d'hemo-catalases: les hemo-b (com la d'Helicobacter pylori, HPC) i les hemo-d catalases (com la de Penicillium vitale, PVC). Experimentalment s'observa que les hemo-b catalases formen Cpd II més fàcilment que les hemo-d. La formació del Cpd II consta de dos processos: la reducció del catió radical porfirínic i la protonació del grup oxoferril. Durant l'estada, es va estudiar el procès de transferència electrònica a la porfirina utilitzant una metodologia desenvolupada recentment. Els resultats mostren que per PVC la reducció és més fàcil que per HPC. Posteriorment hem realitzat una sèrie de optimitzacions de geometria CPMD QM/MM al llarg del camí per la transferència de protó (PT) de la histidina distal a l'oxoferril. Mentre que per HPC aquesta PT és espontània, per PVC l'isòmer hidroxoferrílic és menys estable que el catió imidazoli.

The effect of recombination in Aeromonas

Although several approaches have been attempted, the estimation of recombination frequencies in natural populations ofbacteria remains challenging. Previous studies have demonstrated awide variety of situations among bacterial species, ranging from theclonal diversification of Salmonella or Escherichia coli, which aremainly due to mutation, to the frequent recombination found inNeisseria gonorrhoeae or Helicobacter pylori. Most of the populationstudies done with bacterial species suggest that recombination occursin nature but that it is infrequent compared to mutation. Consequently,bacterial populations consist largely of independent clonal lineages.Our research suggests little or null influence of recombination in thegenetic structure of "Aeromonas hydrophila Species Complex", despite the presence of some strains with recombinant gene fragments.

The effect of recombination in Aeromonas

Although several approaches have been attempted, the estimation of recombination frequencies in natural populations ofbacteria remains challenging. Previous studies have demonstrated awide variety of situations among bacterial species, ranging from theclonal diversification of Salmonella or Escherichia coli, which aremainly due to mutation, to the frequent recombination found inNeisseria gonorrhoeae or Helicobacter pylori. Most of the populationstudies done with bacterial species suggest that recombination occursin nature but that it is infrequent compared to mutation. Consequently,bacterial populations consist largely of independent clonal lineages.Our research suggests little or null influence of recombination in thegenetic structure of "Aeromonas hydrophila Species Complex", despite the presence of some strains with recombinant gene fragments.