title: Elucidated lipid structures of various human stratum corneum investigated by electron paramagnetic resonance spectroscopy.
abstract: BACKGROUND
  Electron paramagnetic resonance (EPR) in conjunction with a slow-tumbling simulation is useful for defining stratum corneum (SC) lipid structure. The objectives of this investigation were to evaluate and elucidate the lipid structure of various human SC as a function of the depth.
  
  
  METHODS
  The SC from mid-volar forearms of human volunteers and a cadaver was stripped consecutively from one to three times using a glass plate coated with a cyanoacrylate resin. Spin probes were used to monitor SC ordering. EPR spectra were analyzed by an EPR slow-tumbling simulation. Keratin solution from human epidermis was mixed with 5-doxylstearic acid (5-DSA) aqueous solution.
  
  
  RESULTS
  EPR analyses of 5-DSA and CHL probes showed immobilized and mobile spectra, respectively. The simulation for 5-DSA spectra showed differences in ordering values of the SC as a function of depth. EPR of keratin/5-DSA showed mobile spectral pattern. In addition, EPR of CHL showed a weak and a broad signal.
  
  
  CONCLUSIONS
  The keratin/5-DSA results imply that the most likely location of 5-DSA probe is in SC lipid. CHL probe may not easily permeate the SC. The EPR results along with the simulation analysis provide elucidated SC lipid structure.
authors.affiliation: Department of Radiological Life Sciences, Graduate School of Health Sciences, Hirosaki University, Hirosaki, Japan. nakagawa@cc.hirosaki-u.ac.jp
authors.forename: Kouichi
authors.initials: K
authors.lastname: Nakagawa
mesh_terms: D000368:Aged; D002102:Cadaver; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D004817:Epidermis / Q000737:chemistry*; D006801:Humans; D053555:Keratin-5 / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D008297:Male; D008563:Membrane Lipids / Q000737:chemistry*; D008954:Models, Biological; D013048:Specimen Handling; D053832:Surgical Tape; D014867:Water / Q000737:chemistry
chemical_list: C503940:KRT5 protein, human; D053555:Keratin-5; D008051:Lipid Bilayers; D008563:Membrane Lipids; D014867:Water