Structural and functional differences in barrier properties of African American, Caucasian and East Asian skin.

Background: Differences in structural and functional skin characteristics have been linked with ethnical background. But racial differences in skin have not been thoroughly investigated by objective methods and the data are often contradictory.

Objectives: This study was undertaken to compare skin barrier-related parameters of the stratum corneum on African American, Caucasian and East Asian skin by objective measurements.

Arginase is overactive in psoriatic skin.

Background: Psoriatic keratinocytes are poorly differentiated and hyperproliferative. Low concentrations of nitric oxide (NO) induce keratinocyte proliferation, while high concentrations induce differentiation. The NO-producing enzyme inducible NO synthase is overexpressed in psoriatic skin, but so is arginase.