Attachment of mesophilic aeromonads to cultured mammalian cells

The interaction between mesophilic aeromonads and cultured mouse adrenal cells was examined. Preliminary experiments indicated that aeromonad attachment was dependent upon inoculum size, incubation time, and incubation temperature. Optimal attachment was observed after 30 min of incubation at 37°C with an inoculum size of 1×10⁷ CFU. Heat-killed and formalin-treated organisms did not attach to the cultured cell system. The attachment of aeromonads to the mammalian cell surface was confirmed by light and scanning electron microscopy. Aeromonad attachment correlated both with the presence of pili and the specific aeromonad species, but not with hydrophobicity or the ability to autoagglutinate. Piliated strains were more likely to show high or moderate attachment.Aeromonas sobria, A. hydrophila, andA. veronii showed a greater ability to bind adrenal cells than didA. caviae. Removal of the pili from twoA. sobria isolates markedly reduced their attachment. In contrast, oneA. hydrophila isolate was strongly adherent after the removal of pili. The hemagglutination patterns produced byA. sobria and the other aeromonad species were distinctly different, but potentially predictive of the ability of aeromonads to attach to cultured mouse adrenal cells. These studies indicate that multiple mechanisms are important for the attachment of mesophilic aeromonads to mammalian cells. This model may prove useful for studying the pathogenesis of aeromonad infections.     

Reduced complexity of activity patterns in patients with Chronic Fatigue Syndrome: a case control study

Objective  

We examined developmental aspects of the emotional awareness of adolescents by evaluating their responses to a self-reported questionnaire based on the Toronto Alexithymia Scale-20 (TAS-20).     

Bonding of ofloxacin to polytetrafluoroethylene suture and colonization byStaphylococcus aureus

Conditions required for in vitro bonding of¹⁴C-ofloxacin (OFX) to polytetrafluoroethylene suture (PTFE) were investigated. Bonding of OFX to PTFE was enhanced 22- and 75-fold in the presence of the cationic surfactant benzalkonium chloride (BAC) or silver and organic solvents (S/O), respectively. The optimal temperature and time of incubation for maximum OFX bonding was 37°C for 1 h (BAC) and 37°C for 25 min (S/O). BAC- and S/O-treated PTFE bound 3.94 nmoles and 17.79 nmoles OFX/cm suture. Prolonged in vitro incubation of OFX/PTFE for 7 days at 37°C in the presence of serum or saline resulted in 50% OFX retention. In vivo studies on OFX/PTFE placed into canine carotid arteries showed 8% OFX retention. The intravenous infusion of coagulase-positiveStaphylococcus aureus into OFX/PTFE animals resulted in colonization. Although significant in vitro bonding of OFX to PTFE was observed, in vivo studies demonstrate an accelerated release and inferior OFX/PTFE activity against microbial colonization.     

Platelet aggregation, rheological parameters and blood glucose profiles in diabetic children (type I) treated with human and porcine insulin

In a three-year bicentric cross-sectional investigation on type I diabetic children between six and eighteen years of age, blood sugar profiles and spontaneous thrombocyte aggregation were assessed besides anamnestic and clinical data. In the children treated with human insulin raised spontaneous thrombocyte aggregation was significantly more frequent than in those treated with porcine insulin. At the same time blood sugar fluctuation from day to day measured between seven and nine a.m. tended to be raised in the children treated with human insulin; the fluctuation in the diurnal profile measured for fourteen days was indeed very much greater. Since the two groups were comparable as to sex distribution, age, duration of disease, quality of compensation, application and dose of insulin, the greater fluctuation of blood sugar in the children treated with human insulin appears to be the cause for the raised spontaneous thrombocyte aggregation.