Wide-angle X-ray diffraction of @entity1 stratum corneum: effects of hydration and XXXX enhancer treatment.

@entity1 @entity2771 @entity6399 @entity28964 @entity12263 @entity4108 @entity9534
Wide-angle X-ray-diffraction experiments were used to investigate the molecular organization of barrier components of @entity1 stratum corneum. Diffraction lines related to the side-by-side lipid packing arrangements in the intercellular bilayers were identified as were patterns arising from secondary protein structures in intracellular keratin. Reflections were also identified which may be produced by proteins in the corneocyte envelopes. The effects of hydration on stratum corneum structure were monitored using 0, 20-40, 40-60, 60-80 and approximately 300% hydrated samples. The packing arrangements in the intercellular lipid bilayers remained the same over the entire hydration range, as did keratin structures. A new diffraction ring, attributable to liquid water, was produced by 300% hydrated samples with a repeat spacing of 0.35 to 0.30-0.29 nm. The effects of three @entity9534 enhancers, @entity4108 , @entity28964 and @entity12263 , on stratum corneum structure were monitored. Treatment with each of the @entity6399 produced additional reflections which were attributed to the presence of the respective liquid enhancers within the stratum corneum. @entity4108 produced an additional reflection at 0.503-0.489 nm, @entity28964 , an additional reflection at 0.486-0.471 nm and @entity12263 , an intense reflection at 0.583-0.578 nm. Reflections characteristic of gel-phase lipids and crystalline lipids also remained after all @entity9534 treatments. These results provide no clear evidence of lipid bilayer disruption by the @entity6399 and suggest that areas of liquid @entity9534 exist within the stratum corneum. The mechanisms underlying @entity2771 synergy with @entity9534 enhancers were investigated. Treatment of stratum corneum with each @entity9534 mixed with @entity2771 gave rise to two additional reflections. One reflection, always positioned at 0.452-0.448 nm, had been observed in control studies following @entity2771 treatment and may have been associated with bilayer structures disrupted by @entity2771 or altered keratin structures. The second reflection was developed by the respective @entity9534 enhancer. For example, treatment with a @entity12263 / @entity2771 mixture produced reflections at 0.457-0.451 nm ( @entity2771 -disrupted lipids or altered keratin) and 0.591-0.578 nm (liquid @entity12263 ). Since the reflection at 0.452-0.448 nm was unaffected by co-application of @entity2771 with @entity9534 enhancers, this study offers no evidence to support the theory that @entity2771 synergy with the @entity6399 occurs through enhanced lipid disruption.
