title: A photoacoustic investigation of the influence of some constituents of the stratum corneum on ultraviolet absorption.
abstract: Photoacoustic spectroscopy (PAS) was used to evaluate light absorption by solid samples. Application of this technique to the human stratum corneum (SC) was used to investigate the influence of some constituents of SC (water, lipids, hydrophilic substances) on ultraviolet (UV) absorption by this tissue. The results showed that the water content of SC modified the PAS signal obtained. For example, there was a fall of over 20% in the UV absorption coefficient when the SC water-content rose from 0 to 30%. Epidermal lipids were not shown to have any direct effect on UV absorption by SC. However, indirectly they do seem to have protected some of the hydrophilic substances from water extraction. After removal of these hydrophilic substances, the UV absorption from SC was greatly decreased. Results indicated that these hydrophilic substances were protected in situ by polar lipids enmeshed within the structure of SC.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008055:Lipids / Q000032:analysis; D012867:Skin / Q000032:analysis / Q000033:anatomy & histology / Q000528:radiation effects*; D013057:Spectrum Analysis; D014465:Ultrasonics; D014466:Ultraviolet Rays; D014867:Water
chemical_list: D000596:Amino Acids; D008055:Lipids; D014867:Water