PubMed · 13972020
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E E POLLI, G LANZAVECCHIA, G JEAN. Ultrastructure of leukocytes during some defence function.. https://pubmed.ncbi.nlm.nih.gov/13972020/
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A modification of von Willebrand' factor/ristocetin cofactor activity test is proposed. Agglutination of formalin-treated platelets is monitored in the aggregation analyzer from changes in the light transmission in the specimen. The test is sensitive and reproducible. It is intended for clinical laboratories to be used in patients with hematological diseases and the endotheliopathy syndrome of different etiology.
Treponema denticola, a suspected periodontal pathogen, was shown to agglutinate and lyse human red blood cells. Both activities were cell-associated, heat-labile, and produced during the exponential growth phase. Hemolytic activity was time-dependent and required incubation at 37 degrees C; further incubation at 4 degrees C increased the hemolysis. Hemagglutination was reduced in the presence of D-glucosamine, EDTA or sodium salicylate, whereas hemolytic activity was affected by calcium chloride, magnesium chloride, EDTA or sodium salicylate. These biological activities may favor a higher concentration of hemin-containing compounds in periodontal sites, and therefore represent additional potential virulence mechanisms.
Twenty-seven Vibrio strains were assessed for virulence-associated biological activities, including iron chelation, hydrolases, haemolysis and haemagglutination. All strains hydrolysed DNA, chitin, gelatin and casein, produced siderophores, and lysed red blood cells. All V. fluvialis, V. cholerae and V. mimicus strains exhibited diverse lipolytic activity distinct from more discriminate lipolysis by V. furnissii. V. furnissii manifested fibrin and mucin hydrolysis but no phosphate or esculin hydrolysis, for which V. fluvialis varied. No strains hydrolysed urea, alginate or keratin. V. fluvialis, V. furnissii and V. mimicus strains failed to exhibit the mannose-sensitive haemagglutination typical of V. cholerae. Some activities may distinguish otherwise phenotypically similar species. Species tested commonly possessed biological activities that may contribute to virulence, although there was no apparent correlation with isolation from human sources.