Joachim Barth

Fluorescence spectroscopy of human skin

The advantages of optical spectroscopy in skin are discussed. The basis for fluorescence spectroscopy is briefly presented. The potential for in vitro and in vivo fluorescence spectroscopy of biotissues is significant, but not yet well developed. With the help of fluorescence spectroscopy and layer-by-layer skin surface strippings technique the important knowledge for autofluorescence spectra from different skin layers have been obtained. Resolution of autofluorescence spectra into discrete excitation-emission bands is presented, related to various skin fluorophores.

Croconazole : an inhibitor of eicosanoid synthesis in A23187-stimulated human polymorphonuclear leukocytes and human whole blood

The aim of this investigation was to ascertain possible inhibitory effects of the antimycotic agent croconazole on eicosanoid biosynthesis. Human polymorphonuclear leukocytes (PMN) and whole blood of healthy donors were pretreated with croconazole in different concentrations (0.8-100 microM) for 5 min followed by the addition of Ca ionophore A23187 (10 microM) and subsequent incubation for 10 min (PMN) and 30 min (whole blood), respectively. Thereupon the eicosanoids were determined by reversed-phase high-performance liquid chromatography. Croconazole exhibited dose-dependent inhibitory activity on the 5-lipoxygenase (5-LOX) of neutrophils. The mean half maximum inhibition concentration (IC50) of croconazole for synthesis of leukotriene B4 (LTB4) and 5-hydroxyeicosatetraenoic acid (5-HETE) was determined as 7.8 +/- 1.7 and 7.6 +/- 0.3 microM, respectively. The mean IC50 value for LTB4 estimated in whole blood was distinctly higher (27.0 +/- 3.1 microM) compared with that determined in PMN. Additionally, an inhibitory effect (IC50 9.8 +/- 2.0 microM) on the production of the cyclooxygenase (COX) product 12-hydroxyheptadecatrienoic acid (HHT) was demonstrated, whereas the production and/or releasing of 12-hydroxyeicosatetraenoic acid (12-HETE) was not attenuated by the azole. Our results in the cell-free 5-LOX system favor a direct inhibitory action of croconazole on 5-LOX, with a relatively high portion (45-77%) of reversibility. In spite of distinctly lower inhibitory potency compared with reference inhibitors such as nordihydroguaiaretic acid and indomethacin, croconazole is an effective inhibitor of arachidonic acid metabolism. Our results suggest that croconazole may be of some benefit in anti-inflammatory therapy.

Anti-inflammatory activity of croconazole, a broad-spectrum antimycotic agent, in the arachidonic acid-induced mouse ear swelling test.

Investigations on croconazole, a novel imidazole compound, suggested antiphlogistic properties in vitro. Hence, its anti-inflammatory capacity was tested in vivo using the arachidonic acid-induced mouse ear swelling test, which is a suitable model for screening inhibitors of the lipoxygenase and/or the cyclooxygenase. Topical application of croconazole (1%/0.01%) to the mouse ear induced a maximal inhibition of edema (inhibition: 39%/33%; p = 0.01) which was as strong as the reference nordihydroguaiaretic acid (inhibition: 38.9%; p = 0.01). These results justify further investigations on croconazole to study potential inhibitory effects on proinflammatory arachidonic acid metabolites.

Fluorescence spectroscopy in human skin diagnostics

The advantages of optical spectroscopy in skin are discussed. The basis for fluorescence spectroscopy (FS) is briefly presented. The potential for in vitro and in vivo FS of biotissues is significant, but not yet well developed. Resolution of autofluorescence spectra into discrete excitation-emission bands is presented, related to various skin fluorophores.