Falanga and coworkers1 in the March ARCHIVES describe a new treatment of venous ulcers using a bilayered, artificial skin equivalent containing both epidermal and dermal components. The unique feature is that both components contain living human cells: an epidermal layer of cultured living human keratinocytes and a dermal layer with living human dermal fibroblasts. Because many variables influence the rate of venous ulcer healing, a new treatment must be compared with a suitable control. And since the unique feature of this dressing is the presence of 2 types of living human cells, the logical control would have been the same dressing with dead cells. This dead-cell dressing could be accomplished by gamma radiation without visible change to the human skin equivalent. In this way, a truly double-blind, properly controlled study could have been carried out.
Epstein E. Questions About Study of Cultured Skin Equivalent for Venous Ulcers. Arch Dermatol. 1998;134(11):1483. doi: