Superb microvascular imaging (SMI) findings of splenic artery pseudoaneurysm: a report of two cases.

Splenic artery pseudoaneurysm (SAPA) is a relatively infrequently encountered but clinically important vascular change, because it carries a high risk of rupture that warrants prompt treatment regardless of its size. Thus, sufficient knowledge is indispensable when seeing chronic pancreatitis patients or post-traumatic patients. Here, we report two such cases. The first case was a 52-year-old woman known to have chronic pancreatitis who presented with hematemesis and hemodynamic instability in which X-ray computed tomography (CT) and color Doppler sonography (CDS) had difficulty visualizing slow blood flow in SAPA, but superb microvascular imaging (SMI) clearly demonstrated the slow blood flow in SAPA, prompting our therapeutic decision to perform rapid embolization. The second case was a 51-year-old woman with post-traumatic SAPA in which 3D SMI enabled us to understand more clearly the topographic relationship between multiple SAPAs as compared with conventional US, leading to a decision to provide immediate surgical treatment. SMI was thought to provide a new insight into the US diagnosis of SAPA. When examining patients suspected of having a SAPA, SMI is an indispensable diagnostic tool at present.

Microbeads display of proteins using emulsion PCR and cell-free protein synthesis.

We developed a method for coupling protein to its coding DNA on magnetic microbeads using emulsion PCR and cell-free protein synthesis in emulsion. A PCR mixture containing streptavidin-coated microbeads was compartmentalized by water-in-oil (w/o) emulsion with estimated 0.5 template molecules per droplet. The template molecules were amplified and immobilized on beads via bead-linked reverse primers and biotinylated forward primers. After amplification, the templates were sequentially labeled with streptavidin and biotinylated anti-glutathione S-transferase (GST) antibody. The pool of beads was then subjected to cell-free protein synthesis compartmentalized in another w/o emulsion, in which templates were coupled to their coding proteins. We mixed two types of DNA templates of Histidine6 tag (His6)-fused and FLAG tag-fused GST in a ratio of 1:1,000 (His6: FLAG) for use as a model DNA library. After incubation with fluorescein isothiocyanate (FITC)-labeled anti-His6 (C-term) antibody, the beads with the His6 gene were enriched 917-fold in a single-round screening by using flow cytometry. A library with a theoretical diversity of 10(6) was constructed by randomizing the middle four residues of the His6 tag. After a two-round screening, the randomized sequences were substantially converged to peptide-encoding sequences recognized by the anti-His6 antibody.