Udo Hoppe

Rapid in vivo measurement of the topography of human skin by active image triangulation using a digital micromirror device

Background/aims: Topometry is one of the most relevant methods for biophysical research on skin in dermatologic and cosmetic science, because it relates very closely to the perceived quality of skin. Taking silicon replicas of skin sites under investigation and measuring those imprints with mechanical or optical profilometers is still the most frequently used method. Direct measurement of the topography of human skin in vivo by active image triangulation avoids the need to make replicas and seems to be a promising alternative.

Effect of Gentian Violet, Corticosteroid and Tar Preparations in Staphylococcus-aureus-Colonized Atopic Eczema

Background: In atopic eczema (AE), skin colonization with Staphylococcus aureus plays a possible role in the pathophysiology of the disease. Methods: Thirty-eight patients with AE were screened for their cutaneous colonization with S. aureus. The antibacterial and clinical efficacy of topical therapy with the antiseptic dye gentian violet, a potent glucocorticosteroid or a tar solution (liquor carbonis detergens) was evaluated in vivo in 21 patients with a density of >104 CFU/cm2 and in vitro. Skin sites were treated twice daily for 4 days with the active drug or a corresponding control. Quantification of S. aureus was done daily during therapy as well as 3 days thereafter. The severity of the lesions was rated by a regional SCORAD. Results: In gentian-violet-treated skin, bacterial density decreased significantly in lesional (p < 0.001) and unaffected skin (p < 0.001). Bacterial densities did not decrease during therapy with glucocorticosteroid or liquor carbonis detergens but dropped afterwards. All therapeutics reduced the severity score, reduction being greatest for the glucocorticosteroid and lowest for liquor carbonis detergens. In vitro, a high antibactericidal efficacy was demonstrated only for gentian violet. Conclusions: Antibacterial therapy with gentian violet not only reduces S. aureus dramatically, but also reduces the severity of the eczema. Reduction of S. aureus after therapy with glucocorticosteroids and LCD seems to be secondary to improvement of the skin condition.

Kinetics of DNA strand breaks and protection by antioxidants in UVA- or UVB-irradiated HaCaT keratinocytes using the single cell gel electrophoresis assay

The aim of this study was to characterize the genotoxic action of UVA and UVB in human keratinocytes by application of the single cell gel electrophoresis assay (SCGE assay). Dose dependence of DNA damage, the time course of its repair, and the influence of cellular antioxidant status were assessed. Irradiation with UVA or UVB both resulted in a dose-dependent increase in the level of DNA damage. A time course study to evaluate the repair kinetics in keratinocytes irradiated with 5 J/cm2 UVA revealed an immediate occurrence of DNA effects which subsequently disappeared within about 1 h, indicating removal of DNA lesions. This rapid repair of DNA damage is consistent with the observation that 5 J/cm2 UVA did not impair cellular viability. In contrast, exposure to 15 mJ/cm2 UVB resulted in a prolonged repair of DNA damage which lasted about 25 h. Thus, the repair kinetics of UVA- and UVB-induced DNA damage clearly differed from each other, implicating the induction of different types of DNA lesions by UVA and UVB. Neither a pretreatment with Mg-ascorbyl phosphate or D,L-alpha-tocopherol, nor depletion of endogenous glutathione altered cellular sensitivity to UVB. In contrast, the DNA damaging effects of UVA could be counteracted by a pretreatment with these antioxidants. These observations confirm that the UVA-induced effects on DNA are related to radical mediated strand breaks and DNA lesions forming alkali-labile sites. The UVB-induced effects mainly occur as a consequence of excision repair-related strand breaks. The observed repair kinetics of DNA lesions and the influence of cellular antioxidant status may help to elucidate protective mechanisms against the carcinogenic effects of UV radiation present in sunlight.

Ultraweak photon emission of human skin in vivo: Influence of topically applied antioxidants on human skin

Publisher Summary This chapter discusses the method to detect ultraweak photon emission (UPE) of human skin in vivo. The monitoring of UPE directly on the skin has the advantages of being noninvasive and providing continuous and convenient monitoring. The effect of the topical application of a-tocopherol and B-carotene was also determined in this study. The UPE detection method provides a useful technique in vivo to determine peroxidative events and efficacy of topically applied antioxidants on human skin. To record the emissions from the skin of human volunteers in vivo, the instruments have to be adapted to special applications. It is necessary to replace small sample compartments and to keep the distance between photocathode and skin surface as short as possible. Avoidance of light from external sources is also necessary. The entire detector head has to be installed in rooms without phosphorescent walls, surfaces, and lamps, and it should be freely movable. Irrespective of theoretical considerations as to whether some kind of physical or biochemical phenomena may be occurring, skin as an organ designed for protection against noxious materials in the environment may be useful as an indicator of free-radical metabolism.

In vitro model for contact sensitization: II. Induction of IL-1β mRNA in human blood-derived dendritic cells by contact sensitizers

Epidermal mRNA for interleukin 1beta (IL-1beta) has been shown to be increased following exposure of mouse skin to sensitizing compounds. In addition, this early upregulation of IL-1beta was specific for contact sensitizers, while expression of IL-1beta was unaffected by irritants. Langerhans cells are the major source of IL-1beta within the epidermis in the induction phase of skin sensitization. Since the isolation of Langerhans cells from skin biopsies results only in low frequencies, we decided to use dendritic cells (DCs) generated from peripheral blood as Langerhans cell equivalents to investigate the ability of five contact sensitizers and one irritant to induce IL-1beta gene expression in vitro. For our studies we cultivated DCs in serum-free medium supplemented with granulocyte/macrophage-colony stimulation factor (GM-CSF) and interleukin 4 (IL-4). The DCs showed a typical dendritic morphology, a characteristic expression of surface markers and high stimulatory capacity for autologous T cells. 5-day-old DCs were incubated with subtoxic concentrations of the contact sensitizers pentadecyl-catechol, 2,4,6-trinitrobenezene sulfonic acid, 2,4-dinitrofluorobenzene, NiSO(4), K(2)Cr(2)O(7) and the irritant sodium dodecyl sulfate. IL-1beta mRNA expression was detected by using the reverse transcriptase-polymerase chain reaction (RT-PCR) technique and non-radioactive hybridization procedures. For all contact sensitizers, expression of IL-1beta mRNA increased, whereas treatment with the irritant SDS had no significant effect on IL-1beta expression. Thus we developed an in vitro system, which may be useful to evaluate allergic potentials of chemicals and products.

The Structure of Preen Gland Waxes from Pelecaniform Birds Containing 3,7-Dimethyloctan-1-ol -an Active Ingredient against Dermatophytes

Abstract A biologically active principle has been isolated from the uropygial gland secretion of the gannet (Sula bassana) exhibiting growth inhibitory activity for Gram-positive bacteria, yeasts, moulds and, in particular, for dermatophytes.The feather lipids of this species consist of monoester waxes predominantly composed of 3,x-dimethylalkanols esterified with fatty acids belonging to homologous series of 2-and 3-methyl-, 2,x-and 3,x-dimethyl-as well as 2,x,y-and 3,x,y-trimethyl-substituted alkanoic acids. For chemosystematic reasons other pelecani form species (Pelecanus crispus, Pelecanus onocrotalus, Phaeton lepturus) and one gaviiform species (Gavia stellata) have also been analysed. The pattern of their preen wax constituents suggest to assume that the Pelecaniformes are polyphyletic with gannets and cormorants being closely related, whereas pelicans and tropic birds are different, both from the former and from each other. Pelicans resemble very much the grebes, while tropic birds seem to be more closely related to the charadriiform, alciform, and possibly to the gaviiform birds.

In vitro model for contact sensitization: I. Stimulatory capacities of human blood-derived dendritic cells and their phenotypical alterations in the presence of contact sensitizers.

Dendritic cells (DC) are highly specialized antigen-presenting cells (APC) located in many non-lymphoid tissues and a specialized form of DC-the Langerhans cell (LC)-is found in the skin. The functionality of LC as APC is crucial for the induction of an allergic contact dermatitis. For a long time LC research has been hampered by the limiting numbers of functionally active LC that could be isolated from human skin. The addition of GM-CSF and IL-4 to the non-adherent fraction of mononuclear cells from peripheral blood generated a large amount of CD1a(+) HLA-DR(+) DC. These in vitro-generated DC exhibited the morphology, phenotype and autologous T-lymphocyte stimulating capacity of the human DC/LC system. We had tested phenotypical alterations of in vitro-generated DC under the influence of subtoxic concentrations of different chemicals and contact sensitizers. In vitro stimulation with the contact sensitizers urushiol, primin, C10-and C11-primin analogues, alantolactone, isoalantolactone and NiSO(4) resulted in a decrease of HLA-DR expression on the surface of these cells if the incubation period did not exceed 3 hr. Incubation with irritants like sodium lauryl sulfate (SLS) and benzalkonium chloride did not change or increase the HLA-DR surface expression under these conditions. With regard to the adhesion molecule ICAM-1, there was no clear difference between irritants and contact sensitizers. But based on the alteration of HLA-DR expression of dendritic cells under short-term exposure conditions, there was a clear-cut difference between irritants and contact sensitizers. In summary, this system can be used to discriminate between contact sensitizers and irritants.

MODULATION DES OXIDATIVEN STRESSES IN DER HUMANEN ALTERSHAUT

Zusammenfassung Oxidativer Streß (UV-Licht, freie Radikale) ist einer der wesentlichen Auslöser für vorzeitige Hautalterung. Als aktive Schutzmechanismen gegen diese oxidativen Schäden, die besonders im Alter zunehmen, können Koenzym Q10 (CoQ10), aber auch exogen applizierte Antioxidanzien wirken.Unsere vergleichenden In-vitro- und In-vivo-Untersuchungen an Haut alter Probanden zeigen anhand der Meßparameter (ultraschwache Photonenemission, Gesamtthiolstatus, Mitochondrienmembranpotential und Zellvitalität), daß die endogene Resistenz gegen UV-Licht in Keratinozyten alter Spender reduziert ist. Diese geringere Resistenz, d.h. der schlechtere Schutz der epidermalen Zellen gegen oxidative Stressoren, insbesondere gegen UV-Licht, kann durch topische Applikation von Verbindungen wie CoQ10 und Antioxidanzien wie alpha-Glucosylrutin (15) deutlich verbessert werden. Placebokontrollierte In-vivo-Studien zeigen außerdem, daß bereits vorhandene, vornehmlich durch Lichtalterung (Photoaging) bedingte Hautveränderungen, wie z.B. sichtbare Fältchen im Bereich der Augenwinkel, durch topische Langzeitbehandlung mit humanidentischem CoQ10 deutlich reduziert werden können.Summary Oxidative stress (UV irradiation, free radicals) plays a significant role in aging. Coenzyme Q10 (CoQ10) and exogenously applied antioxidants can significantly reduce the formation of oxidative stress with increasing age.In our in vitro and in vivo experiments concerning the parameters of ultraweak photon emission (UPE), intracellular thiol status, mitochondrial membrane potential and cell vitality, we demonstrated a diminished resistance in keratinocytes of old donors against UV irradiation. This reduced epidermal resistance against oxidative stressors, i.e. UV irradiation, can be improved by topical application of CoQ10 and antioxidants like alpha-glucosylrutin (15). Furthermore, our in vivo investigations show that wrinkles around the region of the eyes (“crow feet”) could be reduced by long-term application of CoQ10.

Texture Analysis of the Surface of the Human Skin

The roughness parameters known from surface engineering often used to describe the microtopography of the surface of the skin do not, by definition, take into account the two-dimensional relationships of the stratum corneum. An approximate description of these relationships can be obtained by scanning several radial profile sections. A more detailed analysis of the characteristic surface relief of the skin can also be based on the texture parameters used to characterize many natural structures. These types of parameters can be extracted from the gray level images of an impression of the surface of the skin--a replica--that has been magnified under a microscope, photographed with a CCD camera and subsequently subjected to image analysis by a digital computer. The purpose of this study is to determine not only the usefulness of texture parameters for describing the morphology of the surface of the human skin but also whether, for example, cosmetically treated skin can be detected by means of texture analysis.

Phenotype and Alloactivating Capacity of Dendritic Cells Generated under Different Culture Conditions from Human Peripheral Blood

Dendritic cells (DCs) are a family of specialized cells distributed in various tissues with stimulatory capacities for primary and secondary immune responses especially by antigen presentation to T-lymphocytes. The isolation of skin associated DCs from skin biopsies is hampered by the limited numbers of DCs and tedious isolation procedures. Recently, several investigators described procedures for the in vitro generation of cells with the feature of DCs/Langerhans cells (LCs) from human peripheral blood to have sufficient numbers of cells to investigate the characteristics of the cells (Caux et al., 1992; Thomas et al., 1993; Sallusto and Lanzavecchia, 1994).