http://repub.eur.nl/res/aut/7136/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/20896/ 2000-06-23T00:00:00Z Cystic fibrosis (CF) is the most common single gene disorder in The Netherlands and occurs approximately once in every 3600 children born alive. The heterozygous carrier frequency has been estimated to be approximately 1 :30. The defective gene was identified in 1989 and appeared to be located on chromosome. It codes for the cystic fibrosis transmembrane conductance regulator (CFTR), which acts as a transmembrane chloride channel. The most frequent mutation of this gene is the deletion of phenylalanine at position 508 ("F508). Almost 60% of the known CF patients in The Netherlands are homozygous for the "F508 mutation. More than 700 additional CFTR mutations related to CF have been identified as oflate May 1997 by the CF Genetic Analysis Consortium. The gene defect results in significant morbidity and affects mainly the respiratory tract and the pancreas. The CF lung presents an unique environment to microbial pathogens. The combination oflow or absent chloride secretion and an increased sodium absorption results in relative dehydration of the ainvays. Consequently, the disease is characterized by the production of abnonnally viscid secretions in epithelial tissues. Mucociliary clearance of bacteria from the lungs is impaired because of the viscid, dehydrated nature of the airway epithelia. Chronic ainvay inflammation leads to excessive secretion of purulent mucus and to obstmction of the airway which in turn causes bronchiectasis, pulmonary hypertension with cor pulmonale, haemoptysis, pneumothorax and, finally, respiratory failure. The exacerbation of puhnonary infections is the major cause of morbidity and mortality in patients with CF. Aggressive early treatment of respiratory infections is a critical success factor in the treatment ofCF patients. Thirty years ago, most patients died in infancy. Nowadays, patients born in the 1990's are likely to live up to a median age of 40 years. http://repub.eur.nl/res/pub/8637/ 1996-01-01T00:00:00Z Eighty-seven strains of Pseudomonas aeruginosa were typed by random amplification of polymorphic DNA (RAPD) and pulsed-field gel electrophoresis (PFGE) of macrorestriction fragments. Stains were clustered on the basis of interpretative criteria as presented previously for the PFGE analysis. Clusters of strains were also defined on the basis of epidemiological data and subsequently reanalyzed by RAPD. It was found that in an RAPD assay employing the enterobacterial repetitive intergenic consensus sequence ERIC2 as a primer, single band differences can be ignored; in this case, clonally related strains could be grouped as effectively and reliably as with PFGE. These data could be corroborated by the use of other primer species. However, some primers either showed reduced resolution or, in contrast, identified DNA polymorphisms beyond epidemiologically and PFGE-defined limits. Apparently, different primers define different windows of genetic variation. It is suggested that criteria for interpretation of the ERIC2 PCR fingerprints can be simple and straightforward: when single band differences are ignored, RAPD-determined grouping of P. aeruginosa is congruent with that obtained by PFGE. Consequently, this implies that RAPD can be used with trust as a first screen in epidemiological characterization of P. aeruginosa. The ability to measure the rate of molecular evolution of the P. aeruginosa genome clearly depends on the choice of restriction enzyme or primer when RAPD or PFGE, respectively, is applied for the detection of DNA polymorphisms.