Human epidermis

In vitro studies on the absorption of dioctyltin dichloride and dioctyltin EHMA through rat and human epidermis (occluded and unoccluded) were performed by... 

Ciba-Geigy Ltd. 1985. In vitro absorption through human epidermis of Reofos 50 and Reolube with cover letter dated October 16, 1985. EPA/OTS Public Files. NTIS OTS0512802. 

Szabo G, Gerald AB, Patnak MA, Fitzpatrick TB (1969) Racial differences in the fate of melano-somes in human epidermis. Nature 222 1081-1082... 

Corsini, E. et al., Selective induction of interleukin-12 by chemical allergens in reconstituted human epidermis, ATLA, 27, 261, 1999. 

Melanin is formed by a photochemical reaction, so the concentration of melanin within the human epidermis (the outer layer of the skin) increases following exposure to photochemical reactions with tyrosine in the skin. This increase is seen readily by the formation of a suntan. This increase in the concentration of melanin following exposure to the sun is more obvious for fair-skinned people, although darker people usually tan more quickly because melanin is produced more efficiently in their skins. 

Because of practical reasons, the human epidermis can be generally divided into two main layers, the stratum corneum and the viable epidermis. 

Reconstructed Human Epidermis Equivalents Because of the limited availability of human skin, reconstructed human epidermis equivalents are under investigation to serve as membranes in permeation experiments. A summary on these replacement tools has been recently published by Netzlaff et al. [92], First results of a German prevalidation study have shown the suitability of such bioengineered human epidermis equivalents in permeation studies [93],... 

Reconstructed Human Epidermis in Combination with MTT-Assay... 

F. Netzlaff, C.-M. Lehr, P. W. Wertz, and U. F. Schaefer. The human epidermis models EpiSkin , SkinEthic and EpiDerm An evaluation of morphology and their suitability for testing phototoxicity, irritancy, corrosivity, and substance transport. Eur. J. Pharm. Biopharm. 60 167-178 (2005). 

H. Kandarova, M. Liebsch, H. Spielmann, E. Genschow, E. Schmidt, D. Traue, R. Guest, A. Whittingham, N. Warren, A. O. Gamer, M. Remmele, T. Kaufmann, E. Wittmer, B. De Wever, and M. Rosdy. Assessment of the human epidermis model SkinEthic RHE for in vitro skin corrosion testing of chemicals according to new OECD TG 431. Toxicol. In vitro 20 547-559 (2006). 

F.-X. Bernard, C. Barrault, A. Deguercy, B. De Wever, and M. Rosdy. Development of a highly sensitive in vitro phototoxicity assay using the SkinEthic(TM) reconstructed human epidermis. Cell Biol. Toxicol. 16 391 100 (2000). 

M. Liebsch, C. Barrabas, D. Traue, and H. Spielmann. Development of a new in vitro test for dermal phototoxicity using a model of reconstituted human epidermis. ALTEX 14 165-174 (1997). 

Odland GF (1960) A submicroscopic granular component in human epidermis. J Invest Dermatol 34 11-15... 

Roberts, J.R., DeFrietas, A.S.W., and Bidney, M.A.J. Influence of lipid pool size on bioaccumulation of the insecticide chlordane by northern redhorse suckers (Maxostoma macrolepidotimij, J. Fish. Res. Board Can., 34(l) 89-97, 1977. Roberts, M.S., Anderson, R.A., and Swarbrick, J. Permeability of human epidermis to phenolic compounds, /. Pharm. Pharmaa, 29 677-683, 1977. 

Lupulescu A. 1973. Electron microscopic autoradiography of 3H-kerosene in human epidermis 13th annual meeting of American Society for Cell Biology. Journal of Cell Biology 59(2). 

Lupulescu AP, Birmingham DJ. 1976. Effect of protective agent against lipid-solvent-induced damages Ultrastructural and scanning electron microscopial study of human epidermis. Arch Environ Health 31(l) 33-36. 

Lupulescu AP, Birmingham DJ, Pinkus H. 1973. An electron microscopic study of human epidermis after acetone and kerosene administration. J Invest Dermatol 60(l) 33-45. 

The EpiDerm (EPI-200) skin model is mechanistically and functionally related to EPISKIN. The assay consists of normal human epidermal keratinocytes, which have been cultured in a chemically defined medium to produce a stratified, highly diEerentiated, organotypic tissue model of the human epidermis. 

Roberts MS, Anderson RA, Swabrick J. 1977. Permeability of human epidermis to the phenolic compounds. J Pharm Pharmacol. 29 677-683. 

Schafer-Korting, M., Bock, U Gamer, A., Haherland, A., Haltner-Ukomadu, E., Kaca, M., Kamp, H Kietzmann, M. et al. (2006) Reconstructed human epidermis for skin absorption testing results of the German prevalidation study. Alternatives to Laboratory Animals, 34, 283-294. 

The remarkable efficacy of topical corticosteroids in the treatment of inflammatory dermatoses was noted soon after the introduction of hydrocortisone in 1952. Numerous analogs are now available that offer extensive choices of potencies, concentrations, and vehicles. The therapeutic effectiveness of topical corticosteroids is based primarily on their antiinflammatory activity. Definitive explanations of the effects of corticosteroids on endogenous mediators of inflammation await further experimental clarification. The antimitotic effects of corticosteroids on human epidermis may account for an additional mechanism of action in psoriasis and other dermatologic diseases associated with increased cell turnover. The general pharmacology of these endocrine agents is discussed in Chapter 39. 

B. (2005). Ultraviolet B-induced DNA damage in human epidermis is modified by the antioxidants ascorbic acid and D-a-tocopherol. Journal of Investigative Dermatology, 124, 304-307. 

Figure 12 In vitro permeation through human skin and in vivo animal data after dermal application of fentanyl MDTS. (a) Absorption of fentanyl across human epidermis. Comparison of a fentanyl MDTS and Duragesic 50 TS. (b) Mean plasma concentration of fentanyl after a fentanyl MDTS and Duragesic 50 TS in male pigs (n = 7).

Mammalian skin must be tough, water-resistant, self-renewing, and rapidly healing. The outer layers of cells or epidermis consist principally of keratinocytes, epithelial cells specialized for formation of keratin (Fig. 7-31). In the inner layer of the epidermis the basal stem cells divide, providing a constant outward flow of cells which become progressively flattened, dehydrated, and filled with keratin fibrils.3 The outer layers contain only dead cells which are finally sloughed or abraded from the surface. Human epidermis is completely renewed in about 28 days ... 

Fairley, J. A., Scott, G. A., Jensen, K. D., Goldsmith, L. A., and Diaz, L. A. (1991). Characterization of keratocalmin, a calmodulin-binding protein from human epidermis./ Clin. Invest. 88, 315-322. 

Gibbs, S., and M. Ponec. 2000. Intrinsic regulation of differentiation markers in human epidermis, hard palate and buccal mucosa. Arch Oral Biol 45 149. 

Breathnach, A.S., et al. 1973. Freeze fracture replication of cells of stratum corneum of human epidermis. J Anat 114 65. 

Schaller, M., R. Steinle, and H.C. Korting. 1997. Light and electron microscopic findings in human epidermis reconstructed in vitro upon topical application of liposomal tretinoin. Acta Derm Venereol 77 122. 

Apparent Fluxes of Estradiol and L-Glutamic Acid through Human Epidermis During a Three Stage Experiment for Two Pulsing Protocols. Enhancement Ratios and Damage Ratios for Both Compounds are also Given (n = 3)... 

Komatsu N, Takata M, Otsuki N, et al. Expression and localization of tissue kallikrein mRNAs in human epidermis and appendages. J Invest Dermatol 2003 121 542-549. 

Normal human epidermis exhibited homogeneous caspase 14 staining in spinous and granular layers and moderate staining in the basal layer, with evidence of nuclear... 

Alibardi, L. et al. Ultrastructural localization of caspase-14 in human epidermis. J Histo-chem Cytochem. 52, 1561, 2004. 

Yannas s invention mimics the structure and function of the upper two layers of natural skin. It consists of an upper layer about 0.023 mm thick made of an elastic silicone material that, like the human epidermis, acts as a harrier to the loss of moisture from the body. Silicones are siloxane polymers to which are bonded various organic radicals (groups of atoms that contain carbon). The chemical structures of siloxane and a typical silicone polymer are shown on page 50. 

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