PubMed · 13892919
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G H FINDLAY. 1962. Epidermal phosphate.. https://doi.org/10.1111/j.1365-2133.1962.tb13503.x
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Generalized pustular psoriasis (GPP) is a serious dermatological disease characterized by fever, chills, rigors, and generalized pustule formation on the skin. Previous analyses in Japan have led to the proposal to divide GPP into two groups, one with a history of ordinary psoriasis (pso(+) GPP) and the other without a history of psoriasis (pso(-) GPP). Clinically the onset of the pustular outbreak is earlier in pso(-) GPP, which occurs more frequently after infections, whereas pso(+) GPP occurs more frequently following corticosteroid therapy. Substantial differences are also noted in HLA analyses. Activation of neutrophils is a basic mechanism in both types of GPP. Although the epidermal structural changes in GPP are usually not so prominent as those in psoriasis vulgaris, pso(+) GPP shows a more psoriasiform architecture than pso(-) GPP. Analysis of epidermal cell proliferation in GPP indicates that it is not less than that seen in psoriasis vulgaris. The occasional psoriasiform epidermal architecture especially seen in pso(+) GPP may be considered to be a steady-state condition achieved after epidermal cell proliferation has continued for a sustained period. Various inflammatory cytokines appear to be involved in the neutrophilic infiltrate seen in GPP.
In vitro tests were performed to understand the effects of topical vehicles on the permeability of ketoprofen through artificial lipid barriers and heat-separated human epidermis consisting of stratum corneum and viable epidermis. Ketoprofen was selected as the model penetrant. Human epidermis and artificial membranes made from several mixtures of free fatty acids, cholesterol, cholesteryl ester, ceramides, and triglycerides were used as permeation matrices in untreated conditions and after pretreatment with petrolatum, wool alcohols ointment, or triglycerides. Apparent permeability and diffusion coefficients as well as the solubility of the drug in the artificial lipid matrices were ascertained. The solubilities of drugs and vehicle components that depend on the composition of the lipid matrix predominantly control the permeability of the barrier. Ceramides and cholesterol reduce the permeability and solubility, whereas triglycerides have the opposite effect. The vehicle effects in artificial membranes correspond to those in epidermis observed with samples pretreated with the aforementioned bases. The logarithms of the permeabilities of untreated and pretreated lipid mixtures 3, 4, and 5 are very well correlated with those of the permeabilities of heat-separated epidermis (r > = 0.9868). The artificial mixture containing all five lipids mentioned gives the best approximation to human epidermis. This result indicates comparable vehicle effects although the composition of the artificial mixture was adapted only in a simplified manner to the horny layer lipid phase. This lipid matrix or similar mixtures, therefore, are convenient tools for investigation into the effects of dermatological vehicles.
The water content of the stratum corneum (SC) is a key factor in skin barrier homeostasis; it is intimately related to both skin condition and skin permeability. Studies of water uptake in excised human SC show strong similarities and allow characterization of the equilibrium SC water sorption isotherm in terms of widely used theoretical models. At low water activities, SC water sorption resembles that in other keratinized tissues (i.e., wool and horn), whereas at high water activities, it resembles that in polymeric hydrogels. In this paper, theoretical water sorption models [Brunauer-Emmett-Teller (BET), D'Arcy-Watt, and Frenkel-Halsey-Hill] are fit to the combined human SC water sorption data from our laboratories and others. Each of these models provides a satisfactory description of the equilibrium water content of human SC over the water activity range 0.03-1.0. An accompanying paper discusses the implications of SC water sorption on water mobility in corneocytes and on SC permeability.