Peptic ulcer occurrence in follow-up of chronic gastritis in patients with treated and not eradicated CagA-positive Helicobacter pylori infection.

The aim of the present prospective investigation was to study 49 dyspeptic Helicobacter pylori (HP)-positive (HP+) or -negative (HP), CagA+ and CagA- patients with a normal pattern or pure chronic gastritis at initial histology as well as normal features or hyperemic gastropathy at initial endoscopy in a two-year follow up. All the HP+ patients were treated with omeprazole 20 mg twice a day plus amoxicillin 1 g twice a day for two weeks. No substantial change was seen in gastritis in CagA+ patients in whom the infection was not eradicated, and, in contrast, a progressive improvement in 13/14 successfully treated patients was found. At endoscopy, a progressive change to a normal picture was seen in 8 and no change in 6 of 14 patients whose HP infection was eradicated, in contrast a worsening in the 9 HP+ patients who were still infected was observed. In particular, peptic lesions arose in 6 of 21 CagA+ patients in whom the infection was not eradicated. In conclusions, the lack of change in chronic gastritis at histology and the progressive worsening of endoscopic hyperemic gastropathy (with peptic lesions arising in 28,6%) when HP+ CagA+ infection is not eradicated, unlike the progressive improvement of the anatomoclinical condition in the patients whose infection was eradicated, draws attention to the relevance of eradicating HP in CagA+ patients even when no peptic lesion is found at initial endoscopy.

Effect of the conformation and orientation of adsorbed fibronectin on endothelial cell spreading and the strength of adhesion.

The effect of surface hydrophobicity upon the conformation of the cell binding domain of fibronectin (Fn) and the influence of Fn conformation on bovine aortic endothelial cell (BAEC) adhesion were examined. The free sulfhydryl group of Fn located near the cell binding domain was selectively labeled with acrylodan, a polarity sensitive fluor. Fluorescence emission was monitored in solution and upon adsorption to hydrophilic glass and hydrophobic silanized glass. The acrylodan-labeled Fn emission maximum shifted to longer wavelengths upon adsorption and the shift was greater for acrylodan-labeled Fn adsorbed to hydrophilic glass than hydrophobic silane, suggesting that the acrylodan was in a more solvent accessible environment on glass than silane. BAEC, suspended in serum-free medium, attached for 15 or 120 min onto glass or silane surfaces containing preadsorbed Fn, after which cell spreading and the strength of adhesion in a parallel plate flow chamber were measured. Cell spreading was similar on both surfaces after 15 min attachment, but BAECs were more spread on glass than silane after 120 min. At low surface concentrations of Fn, BAECs were more adherent on glass than silane. At higher surfaces concentrations, adhesion was similar. After a 2-h incubation in serum-free medium, cells on glass showed more extensive development of focal contacts as determined by immunofluorescent staining for vinculin. Cell adhesion under flow was reduced on silane by inhibition of protein synthesis with cycloheximide, suggesting that cell attachment to silane was promoted by cellular synthesis of Fn. The results indicate that changes in the conformation of the Fn cell binding domain affect Fn affinity for its cell surface receptor.