Yumiko Oka

Epimorphin acts to induce hair follicle anagen in C57BL/6 mice

Epimorphin is a mesenchymal morphogen that has been shown to mediate epithelial‐mesenchymal signaling interactions in various organs. We now show that epimorphin functions in hair follicle morphogenesis; using a novel ex vivo organ culture assay, we define a mechanism for epimorphin signaling that may provide insight into general developmental processes. We found that epimorphin was produced by follicular mesenchymal cells and bound selectively to follicular epithelial cells, and that treatment with recombinant epimorphin could stimulate procession of hair follicles from telogen (resting stage) to anagen (growing stage). Based on analyses of epimorphin proteolytic digests that suggested a smaller peptide might be able to substitute for the full‐length epimorphin molecule, we determined that pep7, a 10‐amino acid peptide, was capable of inducing telogen‐to‐anagen transition both in the culture assay and in the mouse. That pep7 showed maximal activity only when modified with specific sulfhydryl‐reactive reagents suggested that a particular structural conformation of the peptide was essential for activity; molecular dynamics studies were pursued to investigate the active peptide structure. These findings define a previously unknown morphogenic process in the hair follicle that may have applications to many other organs.—Takebe, K., Oka, Y., Radisky, D., Tsuda, H., Tochigui, K., Koshida, S., Kogo, K., Hirai, Y. Epimorphin acts to induce hair follicle anagen in C57BL/6 mice. FASEB J. 17, 2037–2047 (2003)

An infection-resistant PTFE vascular graft; spiral coiling of the graft with ofloxacin-bonded PTFE thread

OBJECTIVE To develop an infection-resistant polytetrafluoroethylene (PTFE) vascular graft for potential clinical use in grafting in sites of bacterial contamination and in replacement of the infected grafts. SETTING Experimental study in rabbits. MATERIALS AND METHODS An antibiotic ofloxacin (OFLX) was bonded to a sheet of PTFE by impregnation, which was cut and twisted into fine threads. The in-vitro antibacterial activity of OFLX-PTFE thread was determined by measuring the zone of growth inhibition against Escherichia coli. The thread was spirally coiled around a ridged outerwall PTFE to make the OFLX-PTFE graft. OFLX-PTFE graft or control graft was interposed in the inferior vena cava (IVC) of rabbits and the entire graft was covered with fibrin containing a fixed number of E. coli. Three or 7 days after the grafting, the grafts with perigraft tissue were harvested and subjected to bacteriological studies. RESULTS In spite of early phase rapid elution of OFLX, a significant antibacterial activity was retained for more than 2 weeks. The antibacterial activity of OFLX-PTFE threads implanted in the subcutaneous space of rabbits decreased to 48% after 24 h and to approximately 1% after a week. The swab culture of all the control grafts was positive, while only one of 13 PTFE-OFLX grafts was positive. The number of viable bacteria in the perigraft tissue of OFLX-PTFE grafts was remarkably low in comparison with that of control grafts. Thus, the OFLX-PTFE grafts exhibited a marked in-vivo antibacterial activity. CONCLUSION By a unique method, it was possible to furnish PTFE graft with an excellent infection-resistant property, without affecting the original biological behaviour.