Bacterial endotoxin adhesion to different types of orthodontic adhesives

Abstract Bacterial endotoxin (LPS) adhesion to orthodontic brackets is a known contributing factor to inflammation of the adjacent gingival tissues. Objective The aim of this study was to assess whether LPS adheres to orthodontic adhesive systems, comparing two commercial brands. Material and Methods Forty specimens were fabricated from Transbond XT and Light Bond composite and bonding agent components (n=10/component), then contaminated by immersion in a bacterial endotoxin solution. Contaminated and non-contaminated acrylic resin samples were used as positive and negative control groups, respectively. LPS quantification was performed by the Limulus Amebocyte Lysate QCL-1000™ test. Data obtained were scored and subjected to the Chi-square test using a significance level of 5%. Results There was endotoxin adhesion to all materials (p<0.05). No statistically significant difference was found between composites/bonding agents and acrylic resin (p>0.05). There was no significant difference (p>0.05) among commercial brands. Affinity of endotoxin was significantly greater for the bonding agents (p=0.0025). Conclusions LPS adhered to both orthodontic adhesive systems. Regardless of the brand, the endotoxin had higher affinity for the bonding agents than for the composites. There is no previous study assessing the affinity of LPS for orthodontic adhesive systems. This study revealed that LPS adheres to orthodontic adhesive systems. Therefore, additional care is recommended to orthodontic applications of these materials.

Production and characterization of monoclonal antibodies to the EDTA extract of Leptospira interrogans, serovar icterohaemorrhagiae

Monoclonal antibodies (MABs) were produced against an ethylenediaminetetraacetate (EDTA) extract of Leptospira interrogans serovar icterohaemorrhagiae being characterized by gel precipitation as IgM and IgG (IgG1 and IgG2b). The EDTA extract was detected as several bands by silver staining in SDS-PAGE. In the Western blot the bands around 20 KDa reacted with a monoclonal antibody, 47B4D6, and was oxidized by periodate and was not digested by pronase, suggesting that the determinant is of carbohydrate nature. Immunocytochemistry, using colloidal gold labeling, showed that an EDTA extract determinant recognized by monoclonal antibody 47B4D6, is localized under the outer envelope of serovar icterohaemorrhagiae. The MAB raised against the EDTA extract was not able to protect hamsters from lethal challenge with virulent homologous leptospires.

Comparison of outer membrane protein and lipopolysaccharide profiles of enterotoxigenic Escherichia coli strains isolet in Säo Paulo, Brazil

The outer membrane protein (OMP) and lipopolysaccharide (LPS) patterns of 12 strains of serogroups of enterotoxigenic E. coli frequntly isolated in Säo Paulo city werte determined by fractionation techniques and by sodium dodecyl sulfate-plyacrylamide gel electrophoresis (SDS-PAGE). Five O6, three O78 and four O128 serogroup isolates of different serotypes (flagellar antigens) and virulence factors (toxins and colonization factor antigens) showed a high degree of variability in their OMP pattern and at least nine groups could be identified. The analysis of LPS aptterns by SDS-PAGE showed a homogenous profile for the O6 strains and some minor differences for the O128 and 078 strains. The oresented data indicate that analysis of OMP and LPS by SDS-PAGE may further improve the discriminating ability of extensively used serological techniques or the detection of virulence factors and could be a useful tool in epidemiological studies of enterotoxigenic E. coli (ETEC) strains from this area

Cationic interactions in the lipoplysaccharide of Desulfovibrio vulgaris

Foram utilizadas as técnicas de cromatografia à liquido de alto desempenho (HPLC), análise por raio-X EDAX) e eletroforese em gel de poliacrilamida (SDS-PAGE) na investigaçäo das interaçöes entre vários cátions e lipopolissacarídeo (LPS) extraído da espécie bacteriana Desulfovibrio vulgaris. O LPS demonstrou afinidades variáveis para diferentes íons divalentes. Eletrodiálise removeu a maioria dos íons Fe (II) do LPS e resultou num aumento dos íons Ca. A HPLC e SDS-PAGE demonstraram diferenças na estrutura de LPs isolado de células ricas ou pobres em Fe(II), que indicaram que o Fe(II)