Diurnal dependence of skin reactions in the administration of external substances

In order to investigate the influence of the application time of the day on skin reactions, test persons were treated with various substances inducing experimental inflammation in human skin. Additional tests provided us with data regarding the antiinflammatory activity of topical glucocorticoids on the experimental inflammation as well as the vasoconstrictive activity dependent on the application time of the day. Although all tests showed great individual scattering ranges, statistical evaluation did not reveal any clear evidence for the supposition that pharmacological responses of the skin may be influenced by the hour of the topical application. Thus, it seems not likely that the success of topical treatment of toxic dermatitis by means of glucocorticoids depends on the hour of application.     

Regulatory classification of substances oxidized to skin sensitizers on exposure to air

Regulatory classification of substances in the European Union (EU) is intended to identify their hazardous toxicological properties in a formal and harmonized manner. In the regulatory work, a specific chemical with its molecular structure is classified as a skin sensitizer. This implies that the compound is stable throughout its lifetime. The purpose of the present paper is to discuss the problem of skin sensitizing oxidation/degradation products formed by air exposure of various materials or substances with very low allergenic activity. In regulatory classification work on skin sensitizers, the intrinsic suspectibility of a chemical to air oxidation (autoxidation) should be taken into consideration. We give examples of natural terpenoid materials, but the concept of allergens formed by air oxidation can apply to other materials widely used in industrial products. If a positive classification is made for a substance with a known chemical structure, a note should indicate that the primary chemical structure of the notified substance is not a skin sensitizer, but that (some of) its oxidation products are. Complex mixtures which inevitably contain sensitizing oxidation products should (on the basis of sufficient evidence) be classified as skin sensitizing.     

Metabolism of foreign substances in human skin and hair follicles

Human skin has an inducible aryl hydrocarbon hydroxylase (AHH) activity which is dependent on cytochrome P-450. The cutaneous AHH-activity is inhibited by 7,8 benzoflavone but not by metapyrone, whereas recently published data showed that AHH-activity in human liver is enhanced by 7,8 benzoflavone and inhibited by metapyrone. These results suggest that AHH activity of human skin depends on different isoenzymes compared with those in human liver.     

Sialic acids and antimicrobial substances in the apocrine glands of porcine perianal skin

The porcine perianal skin shows prominent apocrine glands with large saccular dilatations, whereby the functional significance of the glandular secretions is rather unexplained. Our study focuses on the demonstration of sialoglycoconjugates and antimicrobial substances in these glands, using glycoconjugate histochemical and immunohistochemical methods. The result obtained emphasized the general presence of sialic acids, linked to α2-6Gal/GalNAc and α2-3Gaβl1-4GlcNAc, in the secretory cells. The secretory epithelium and luminal secretions also contained a spectrum of antimicrobial substances, such as lysozyme, IgA, lactoferrin, and the peptide group of β-defensins. Realizing that sialic acids possess diverging functional properties through various saccharide residues, and that antimicrobial substances serve as a non-specific defense against microorganisms, these secretory products may function as protective agents in order to preserve the integrity of the perianal region. This view includes that the amounts of bacteria on the skin surface are controlled and maintained at the certain level.     

Infrared spectroscopy for tracing of topically applied ointment vehicles and active substances on healthy skin

Summary Infrared spectroscopy was used to trace active substances and ointment vehicles applied on the skin. Vaseline and lanoline could be traced after 8 hrs but not olive oil. From the active substances, ethyl-4-amino-benzoate (5%), clioquinol (5%), parabenes (15%), 5,7-dichlor-8-hydroxy-2-methyl-chinolin (5%), balsam of Peru (25%) and pyroleum pini (12%) could be traced 1 hr after application but had disappeared after 8 hrs. Ethylenediamine (1%), chlorcresol (1%), pyroleum lithantracis (5%), were not traceable after 1 hr, and curiously neither neomycine sulphate in spite of its high concentration (20%). The reaction of the skin surface lipids, after application of different substances, was deduced from the spectra. Clioquinol and pyroleum lithantracis seem to give rise to hydrolysis of the triglycerides, the free fatty acids being clearly identifiable. It is felt that infrared spectroscopy can be used as an effective method to trace different substances such as potent allergens on healthy or diseased skin.

---

Zusammenfassung Mit Hilfe von Infrarotspektroskopie wurde versucht aktive Substanzen wie auch Salbengrundlagen nach lokaler Applikation auf der Haut nachzuweisen. Im Gegensatz zum Olivenölkonnten Vaseline und Lanolin 8 Std nach Auftragung gefunden werden. Von den aktiven Substanzen wurden Äthyl-4-amino-benzoat (5%), Clioquinol (5%), Parabene (15%), 5,7-Dichlor-8-hydroxy-2-methyl-chinolin (5%), Perubalsam (25%) und Pyroleum pini (12%) 1 Std nach Auftragung nachgewiesen. Nach 8 Std waren diese Substanzen nicht mehr nachweisbar. Äthylendiamin (1%), Chlorkresol (1%) und Pyroleum lithantracis (5%) wurden nach 1 Std nicht gefunden, interessanterweise gelang auch der Nachweis von Neomycinsulfat trotz hoher Konzentration (20%) nicht. Durch Clioquinol und Pyroleum lithantracis werden wahrscheinlich Triglyceride hydrolisiert, die freien Fettsäuren lassen sich sicher nachweisen.Mit der Infrarotspektroskopie bietet sich eine wertvolle Methode an, mit der verschiedene Substanzen, beispielsweise starke Allergene, in kranker wie auch in gesunder Haut nachgewiesen werden können.