The ability of pili from Pseudomonas aeruginosa K (PAK) to act as an adhesin to human respiratory epithelial cells was examined using an in vitro adhesion assay. Equilibrium analysis of PAK binding to human buccal epithelial cells (BECs) and tracheal epithelial cells (TECs) by means of a Langmuir adsorption isotherm revealed that the maximum numbers of binding sites per epithelial cell (N) were 255 for BECs and 236 for TECs, with apparent association constants (Ka) of 2.8 x 10(-9) and 5.8 x 10(-9) ml/CFU, respectively. Trypsinization of the BECs before the binding assay increased N to 605 and decreased the Ka to 1.7 x 10(-9) ml/CFU. Addition of homologous pili to the binding assay with BECs or TECs or the addition of anti-pilus Fab fragments inhibited PAK adherence. Binding of purified pili to BECs was shown to reach saturation. Purified pili and PAK competed for the same receptor on the BEC surface. Further, by using peptide fragments of PAK pilin (derived from the native pili or produced synthetically) in the binding assay for PAK to BECs, we have presumptively identified the pilus binding domain in the C-terminal region of the pilin and shown that the C-terminal disulfide bridge is important in maintaining the functionality of the binding domain.
We conclude (1) that MVP is an effective but toxic chemotherapeutic regimen for limited NSCLC; (2) the median survival seems to be prolonged; and (3) the role of induction chemotherapy followed by surgery in stage IIIA N2 NSCLC requires a phase III randomized trial to compare it with other treatment modalities.
Previous studies have suggested that the Pseudomonas aeruginosa PAK pilus adhesin moiety resides in an epithelial cell-binding domain located in the C-terminal region of the PAK pilin structural protein. Synthetic peptides Acl7red (a synthetic peptide with a sequence identical to that of PAK pilin residues 128 to 144, with the Cys-129 and Cys-142 residues being in the reduced state) and Acl7ox (a synthetic peptide with a sequence identical to that of PAK pilin residues 128 to 144, with a formed disulfide bridge between the amino acid residues Cys-129 and Cys-142), which should contain the epithelial cell-binding domain, were synthesized. Acl7red and Acl7ox both bound to buccal epithelial cells (BECs) and to ciliated tracheal epithelial cells (TECs). Acl7ox had a Km of 6.40 ,uM for binding to BECs, while Acl7red had a Km of 9.87 I,M. Acl7red bound to the same receptor sites that purified pili did and competitively inhibited the binding of purified PAK pili to BECs. BEC glycoproteins with molecular masses of 82, 55 to 51, and 40 kilodaltons immobilized on nitrocellulose exhibited periodate-sensitive receptor activity for Acl7red; similar activity has been found for PAK pili. Acl7red, Acl7ox, and PAK pili bound to the cilia and luminal portions of the cytoplasmic membrane of human TECs, the same regions to which P. aeruginosa whole cells bind. PAK pilin has an epithelial cell-binding domain that resides in the C-terminal region of the protein.
Percutaneous drainage and sclerosis constitutes a safe and effective treatment for malignant pericardial effusion. Surgical management should be reserved for the small percentage of cases that cannot be controlled by this method.
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