Peptide-based immunoadsorbents: molecular grafting of IgG-Fc-binding epitopes of Protein A onto a de novo-designed helix-loop-helix peptide.

The development of immunoadsorbents that have high specificity for immunoglobulin and no immunogenicity is essential for immunoadsorption treatment of autoimmune diseases. In this study, we designed peptide immunoadsorbents by molecular grafting of the IgG-Fc binding epitopes of Protein A onto a de novo-designed helix-loop-helix peptide. Linear (linG7A5) and cyclic (cyG7A5) grafted peptides were synthesized to test their binding affinity and specificity. Peptide cyG7A5 demonstrated high specificity for human IgG-Fc, with a K(D) of 19 µM, and demonstrated no affinity to other plasma proteins, human serum albumin, or fibrinogen. To evaluate their immunoadsorbance efficiency, the grafted peptides and Protein A were conjugated to polyvinyl acetate resin and tested in a batch-wise process for adsorption removal of IgG from human plasma. The IgG capture capacities of the peptides correlated well with their binding affinities. Interestingly, cyG7A5 showed a higher binding specificity for IgG than did Protein A.

Evaluation of image quality of personal ultrasound imager: Comparison with the conventional machine.

OBJECTIVE: To determine if the image quality of a personal ultrasound imager (PUI) is as good as that of a conventional machine (CM). MATERIALS AND METHODS: Ninety patients were studied by the same operator using both the PUI and CM. The quality of the B-mode images obtained from these patients was scored 0, 1 or 2, defined as poor, fair, or good, respectively. Liver-tumor vascularity depicted by power Doppler imaging (PDI) and directional PDI (DPDI) was classified as 0, no blood signal; 1, dot-like blood signal within the tumor; 2, mild blood-flow signal within the tumor; and 3, abundant blood-flow signal within the tumor. RESULTS: The mean score of PUI and CM B-mode image quality was 7.47±0.92 and 7.54±0.99 (mean±SD), respectively (p=0.531). On PDI, grade of vascularity of the liver tumors determined with the PUI was 4.44 and 4.68 in those determined with the CM (p=0.78). On DPDI, tumor vascularity was 3.12 when scored by the PUI and 4.29 when scored with the CM (p=0.03). The qualities of images acquired by the PUI and CM were significantly correlated. CONCLUSION: The quality of B-mode images acquired using the PUI and CM are statistically the same, and they share a similar ability to detect intratumoral blood-flow signals on PDI. Because of its extreme portability, the PUI is expected to become a valuable diagnostic tool in the clinic.