210 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Figure 2. Electron micrographs of tape strippings of subjects with severe xerosis (grade 4): Persistence of desmosomes in outermost layers of the stratum corneum. First tape stripping from two subjects (A,B). (X200,000 Bar 0.05 Ixm). inner tape strippings between skin xerosis and percentage levels of fatty acids, together with skin xerosis and percentage levels of ceramides (R = + 0.45, p = 0.046 R = -0.45, p = 0.049, respectively). STRATUM CORNEUM DESMOGLEIN I ANALYSIS Figure 5 compares the differences in desmoglein 1 levels in stratum corneum of subjects with normal (grade 1) and xerotic skin (grade 4) conditions. Compared with normal skin, statistically significant increases in desmoglein 1 levels were observed. DISCUSSION An understanding of the composition and structure of the surface layers of the stratum corneum is particularly important, as it is this region of the tissue where skin dryness

SOAP-INDUCED WINTER XEROSIS 211 Figure 3. Electron micrographs of tape strippings of normal skin (grade 1). Morphological changes in lipid organization toward the surface of the stratum corneum: A. First strip absence of bilayers and presence of amorphous lipid material. B. Second strip disruption of lipid lamellae. C. Third strip normal lipid lamellae. (x200,000 Bar 0.05 manifests itself. To begin to characterize this region of the stratum corneum, and to understand skin xerosis, we have used tape stripping as a sampling procedure to inves- tigate the morphological and biochemical changes in desmosomes and intercellular lipids in the surface layers of human stratum corneum. This has the distinct advantage of sampling the tissue layers that interact directly with the environment. Using this technique together with electron microscopic, chromatographic, and electrophoretic methods, we have shown that perturbations in desmosomal degradation, together with