In Reply.—
The most important point raised by Kaiser and Mertz is that of possible sequestration of fibronectin (Fn) by the gelatin in Orabase, since the question of contracture is irrelevant if Fn is not effective in enhancing wound healing. The gelatin content of Orabase may explain, at least in part, why a higher concentration of Fn was needed in this carrier compared with other carriers to see an effect. We also see an accelerated wound healing due to Orabase itself (Table 1, Orabase-control, under the heading "Treatment") similar to that shown in the figure mentioned in Kaiser and Mertz's letter, and we commented on this in our article. However, in our system Fn, added to Orabase, significantly enhanced the rate of wound healing. In addition, Fn in polyethylene glycol, sepharose (Sepharose 4B), dimethyl sulfoxide, and hydrophylic petrolatum all enhanced the rate of wound healing compared with the carrier-phosphate-buffered saline (PBS) alone.