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This in vitro study evaluated the effect of toothpastes with different active ingredients on dentin permeability using an extended protocol including multiple applications and several thermal ageing cycles in the presence or absence of human saliva. The Null hypothesis was that dentin permeability of a hydroxyapatite containing toothpaste (BR), a potassium nitrate (SP) and an arginine and calcium carbonate (EH) containing toothpaste were similar. Dentin permeability was measured as hydraulic conductance using a commercially available capillary flow system (Flodec, Geneva) and results were expressed as % relative to matching controls. Without saliva, the ranking (best first) of dentin permeability was BR(61%) in vivo situation they should be considered to be included in further in vitro permeability testing of desensitizing preparations.

The Los Angeles test is one of the few mechanical test methods that provides information on the quality of railway ballast. However, the Los Angeles value is subject to large variability. Since important economic decisions depend on this value, the reasons for its variability are investigated. An extensive series of tests using four types of rock as well as an in-depth analysis of particle geometry and petrography are carried out. The impact of particle characteristics on the test results is investigated. The deviation of the petrographic composition within a given sample turns out to have a considerable impact on the Los Angeles test results, whereas the influence of the respective deviation of particle geometry is relatively small. The latter effect only comes into play in connection with petrographically homogeneous rock types. The distribution of the geometric features is similar in almost all of the rock types investigated. Due to the large deviation in particle shape and angularity, the sample mass of 10 kg (as provided in the standards EN 1097-2 and EN 13450) is not found to be representative. The necessary number of test repetitions in order to exclude the effect of deviation of particle geometry is estimated. The one result parameter according to the standard, the Los Angeles value, does not allow for discriminating between the amount of abrasion and the fragmentation occurring during the test. An additional result parameter for the estimation of the fragmentation rate is therefore proposed.

Group B streptococcus remains an important neonatal pathogen in spite of widely adopted intrapartum antibiotic administration; therefore immune prophylaxis for GBS infections is highly warranted. In passive immunization and lethal challenge studies with multiple GBS strains, we characterized the protective effect of rabbit polyclonal and murine monoclonal antibodies specific for four multi-functional cell wall anchored proteins, FbsA, BibA, PilA and PilB. Single specificity rabbit sera or mAbs induced high level, but strain dependent protection, while their combinations resulted in superior and broad efficacy against all GBS strains tested. Polyclonal and monoclonal antibodies specific for the pilus proteins exerted very potent opsonophagocytic killing activity in vitro and required the Fc domain for protection in vivo. In contrast, FbsA and BibA specific antibodies failed to show OPK activity, but their Fab fragments fully protected animals, suggesting that blocking the function of these proteins was the major mode of action. These data are supportive for developing immune prophylaxis with human mAbs for prematurely born neonates who receive low levels of antibodies by maternofetal transport and are characterized by not fully developed phagocytic and complement activity.

Group B streptococcus is one of the most important pathogens in neonates, and causes invasive infections in non-pregnant adults with underlying diseases. Applying a genomic approach that relies on human antibodies we identified antigenic GBS proteins, among them most of the previously published protective antigens. In vitro analyses allowed the selection of conserved candidate antigens that were further evaluated in murine lethal sepsis models using several GBS strains. In active and passive immunization models, we identified four protective GBS antigens, FbsA and BibA, as well as two hypothetical proteins, all shown to contribute to virulence based on gene deletion mutants. These protective antigens have the potential to be components of novel vaccines or targets for passive immune prophylaxis against GBS disease.