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An analytical centrifugation technique (LUMiFuge) for mechanical testing is introduced. Measurements on calibrated springs with LUMiFuge and BOSE LM1-ElectroForce TestBench delivered similar values for E-moduli and spring constants. Native cylindrical scaffolds from cancellous femoral bone were successfully tested using this new technique. The E-moduli obtained for scaffolds with trabecular orientation parallel to the cylindrical axis (longitudinal trabeculae) were significantly higher than that of scaffolds with trabeculae perpendicular to the cylindrical axis (lateral trabeculae). The mean value of elastic modulus increased in dependence on the number of stress rounds from 37.3 ± 19.1 to 63.0 ± 24.2 MPa for samples with longitudinal trabeculae and from 16.0 ± 8.1 to 33.3 ± 13.8 MPa for samples with lateral trabeculae, respectively. We assume that due to the mechanical stress a not completely reversible structural displacement of trabeculae occurs, which results in more compact trabecular arrangement and increase of elastic modulus. The new analytical centrifugation technique offers advantages for characterization of mechanical properties of small bone samples. The method is relatively simple, allows simultaneous testing of several samples, non-destructive testing by application of low loads and can be used to follow the influence of repetitive stress on deformation and recovery of the bone. [ABSTRACT FROM AUTHOR]

Pathogenic factors of Staphylococcus aureus (SA) in the development of infective endocarditis (IE) have not been sufficiently investigated. The purpose of this study was to analyze the pathogenesis and virulence factors of SA in patients with IE as compared to patients with uncomplicated bacteremia (un-BAC). This is a retrospective case-control study (2002-2014) performed at a tertiary hospital in Spain. Clinical and epidemiological factors were analyzed. We assessed the presence of toxin genes [toxic shock syndrome toxin 1 ( tst-1) and enterotoxins A ( etA), B ( etB), and D ( etD)] and the potential relationship between accessory gene regulator ( agr) groups and the development of IE confirmed by polymerase chain reaction (PCR). Twenty-nine patients with IE were compared with 58 patients with uncomplicated S. aureus bacteremia (SAB). As many as 75.9 % of patients had community-acquired IE ( p < 0.005). Multivariate analysis revealed that there is a significant relationship between community-acquired infection and severe sepsis or septic shock and IE. Also, a minimum inhibitory concentration (MIC) of vancomycin ≥1.5 μg/ml was found to be associated with IE. The agr group I was prevalent (55.2 % vs. 31.0 %; p = 0.030). No association was observed between toxin genes ( tst-1, etA, etB, and etD) and IE. The superantigen (SAg) most frequently found in SA isolates was tst-1 (12.6 %). We found no association between toxin genes and IE, probably due to the small sample size. However, a direct relationship was found between agr I and the development of IE, which suggests that agr I strains may have more potential to cause IE. [ABSTRACT FROM AUTHOR]

Charged phospholipids and mixtures of charged phospholipids with zwitterionic lipids were adsorbed onto polyelectrolyte capsules templated on erythrocytes. The assembly was proved by means of electrophoretic mobility measurements, confocal laser scanning microscopy and flow cytometry. Freeze-fracture electron microscopy proved that the phospholipids assemble as bilayers or multilayers. Single particle light scattering showed that bilayers composed of anionic lipids can be intercalated between subsequent polyelectrolyte inter-layers in a regular manner. Neutral lipids can form multilayers. A pronounced decrease in capsule permeability for small polar dyes upon lipid adsorption was followed by confocal laser scanning microscopy. [ABSTRACT FROM AUTHOR]