Structural Features of Hydrolyzable Tannins Determine Their Ability to Form Insoluble Complexes with Bovine Serum Albumin.

The ability of 32 purified and characterized hydrolyzable tannins to form insoluble complexes with model protein bovine serum albumin was investigated with a turbidimetric 96-well plate reader method. The results showed a clear relationship between the hydrolyzable tannin structure and the intensity of haze that formed during the tannin-protein complexation. In addition to molecular weight, structural features such as number of galloyl groups, degree of oxidative coupling between the galloyls, positional isomerism, and cyclic vs acyclic glucose core were the major structural features that affected the ability of the monomeric hydrolyzable tannins to form insoluble complexes with bovine serum albumin. While oligomers were superior to monomers in their capability to precipitate the model protein, their activity depended less on the functional groups, but mostly on their size and overall flexibility. These results allowed us to construct an equation that predicted the protein precipitation capacity of the studied hydrolyzable tannins with high accuracy.

Detection of Streptococcus pneumoniae carriage by the Binax NOW test with nasal and nasopharyngeal swabs in young children.

The rapid detection of carriage of Streptococcus pneumoniae could assist in the management of pneumococcal infection, such as acute otitis media. We evaluated the reliability of the Binax NOW test in the exclusion and detection of pneumococcal carriage by nasal samples from 139 children and using nasopharyngeal samples from 250 children (aged 6-35 months) with respiratory infection with or without acute otitis media. The Binax NOW test results were compared with culture-based detection of carriage of S. pneumoniae. The Binax NOW test from the nasal samples had a sensitivity of 95%, a specificity of 78%, and the positive and negative predictive values were 83 and 93%, respectively; and for the nasopharyngeal samples the corresponding numbers were 88%, 95%, 96%, and 87%. When rapid knowledge of the carriage status of S. pneumoniae is needed, the Binax NOW test is a reliable method for the exclusion of carriage using nasal sampling, and in the detection of carriage using nasopharyngeal sampling.