Petra Johansson

Bacterium-host protein-carbohydrate interactions

Publisher Summary This chapter investigates the bacterium–host protein–carbohydrate interactions, and to illustrate this, briefly discusses two cases: recognition of globo glycolipids by uropathogenic Escherichia coli ( E. coli ) and recognition of glycoconjugates by the gastric colonizer Helicobacter pylori ( H. pylori ). Binding of a radiolabeled clinical isolate of E. coli to a long list of globo series and other glycolipids separated on thin-layer chromatography (TLC) plates revealed a binding to all species carrying galabiose in the terminal or internal position. H. pylori appears to have several carbohydrate-binding specificities. In the case of E. coli , FimH on type 1 pili and recognizing Man oligosaccharide are required for the establishment of bladder infection, whereas PapG on P pili and binding the galabiose epitope are requirements for the more serious pyelonephritis to occur. So, these interactions represent two separate niches of urinary tract infection. In the case of H. pylori , a similar map is far from clear.

Nanoporous TiO(2) Thin Film on Titanium Oral Implants for Enhanced Human Soft Tissue Adhesion: A Light and Electron Microscopy Study

BACKGROUND Previous experimental studies have demonstrated direct soft tissue attachment for nanoporous titanium dioxide (TiO(2) ) thin film on implants, while implants without TiO(2) thin film have not shown this capability. PURPOSE The aims were to evaluate and compare TiO(2) surface-modified experimental microimplants with unmodified microimplants with respect to tissue interaction of the human oral mucosa evaluated by light microscopy on ground sections and semithin sections and transmission electron microscopy on ultrathin sections, and to characterize the inflammatory response and the level of the marginal bone resorption. MATERIALS AND METHODS The study was a single-center, randomized, comparative, clinical investigation with intrasubject comparison of implants with and without TiO(2) thin film in 15 patients. RESULTS Two comparator microimplants showed mild erythema and expulsion of fluids. The surrounding tissues around all test implants were clinically healthy. The oral mucosa in contact with the abutment part of the microimplant was 72% for the test implants and 48% for the comparator implants, a statistically significant difference (p =.0268). No statistically significant difference was found in other histological variables. The marginal bone loss in 14 weeks was 0.5 mm for the stable test (n = 11) and 1.7 mm for the stable comparator implants (n = 9; p = .0248). CONCLUSIONS The nanoporous TiO(2) surface modification has potential clinical benefits because of increased adherence of soft tissue and possible reduced bone resorption.

Different glycosphingolipid composition in human neutrophil subcellular compartments

The binding of a number of carbohydrate-recognizing ligands to glycosphingolipids and polyglycosylceramides of human neutrophil subcellular fractions (plasma membranes/secretory vesicles of resting and ionomycin-stimulated cells, specific and azurophil granules) was examined using the chromatogram binding assay. Several organelle-related differences in glycosphingolipid content were observed. The most prominent difference was a decreased content of the GM3 ganglioside in plasma membranes of activated neutrophils. Gangliosides recognized by anti-VIM-2 antibodies were detected mainly in the acid fractions of azurophil and specific granules. Slow-migrating gangliosides and polyglycosylceramides with Helicobacter pylori-binding activity were found in all acid fractions. A non-acid triglycosylceramide, recognized by Galα4Gal-binding Escherichia coli, was detected in the plasma membrane/secretory vesicles but not in the azurophil and specific granules.Although no defined roles of glycosphingolipids have yet been conclusively established with respect to neutrophil function, the fact that many of the identified glycosphingolipids are stored in granules, is in agreement with their role as receptor structures that are exposed on the neutrophil cell surface upon fusion of granules with the plasma membrane. Accordingly, we show that neutrophil granules store specific carbohydrate epitopes that are upregulated to the plasma membrane upon cell activation.

Inflammatory cytokine release from human peripheral blood mononuclear cells exposed to polyetheretherketone and titanium-6 aluminum-4 vanadium in vitro

Objective To investigate the cytokine expression profiles of blood cells exposed to polyetheretherketone and titanium-6 aluminum-4 vanadium materials in vitro. Materials and methods Coin-shaped samples composed of titanium-6 aluminum-4 vanadium, polyetheretherketone, and blasted polyetheretherketone were manufactured. The surfaces of the coins were characterized using optical interferometry, scanning electron microscopy, and contact angle measurements. Peripheral blood mononuclear cells collected from 10 blood donors were cultured for one, three, and six days in the presence or absence of the coins, and then assayed for cytokine production. Quantification of the peripheral blood mononuclear cells attached to the coins was performed using confocal microscopy after immunofluorescence staining. Results The machined titanium-6 aluminum-4 vanadium coins had a smoother surface topography compared to the machined polyetheretherketone and blasted polyetheretherketone. The highest mean contact angle was noted for the blasted polyetheretherketone, followed by the machined polyetheretherketone and titanium-6 aluminum-4 vanadium. The peripheral blood mononuclear cells produced significantly more proinflammatory cytokines when exposed to the polyetheretherketone surface compared to the titanium-6 aluminum-4 vanadium surface, while the blasted polyetheretherketone induced the highest level of proinflammatory cytokine release from the peripheral blood mononuclear cells. Significantly more cells attached to both polyetheretherketone surfaces, as compared to the titanium-6 aluminum-4 vanadium surface. Conclusion Polyetheretherketone induces a stronger inflammatory response from peripheral blood mononuclear cells than does titanium-6 aluminum-4 vanadium. Surface topography has an impact on cytokine release from peripheral blood mononuclear cells.