Uwe-Frithjof Haustein

Antifungal activity of the essential oil of Melaleuca alternifolia (tea tree oil) against pathogenic fungi in vitro.

The in vitro antifungal activity of tea oil, the essential oil of Melaleuca alternifolia, has been evaluated against 26 strains of various dermatophyte species, 54 yeasts, among them 32 strains of Candida albicans and other Candida sp. as well as 22 different Malassezia furfur strains. Minimum inhibitory concentrations (MIC) of tea tree oil were measured by agar dilution technique. Tea tree oil was found to be able to inhibit growth of all clinical fungal isolates. For the investigated dermatophytes MIC values from 1,112.5 to 4,450.0 micrograms/ml with a geometric mean of 1,431.5 micrograms/ml were demonstrated. Both C. albicans strains and the other strains belonging to the genus Candida and Trichosporon appeared to be slightly less susceptible to tea tree oil in vitro. However, their MIC values, which varied from 2,225.0 to 4,450.0 micrograms/ml (geometric mean 4,080 micrograms/ml), indicated moderate susceptibility to the essential oil of M. alternifolia. The lipophilic yeast M. furfur seemed to be most susceptible to tea tree oil. MIC values between 556.2 and 4,450.0 micrograms/ml (geometric mean 1,261.5 micrograms/ml) were found against the tested M. furfur strains. However, when calculated as percentage tea tree oil of the agar, the above-mentioned concentrations correspond to 0.5-0.44% tea tree oil content. These values are far below the usual relatively high therapeutic concentrations of the agent; approximately 5-10% solution or even the concentrated essential oil are used for external treatment. In comparison with tea tree oil, in vitro susceptibility against miconazole, an established topical antifungal, was tested. As expected, very low MIC values for miconazole were found for dermatophytes (geometric mean 0.2 microgram/ml), yeasts (geometric mean 1.0 microgram/ml), and M. furfur (geometric mean 2.34 micrograms/ml). It is suggested that the in vivo effect of tea tree oil ointment in the therapy of fungal infections of the skin and mucous membranes as well as in the treatment of dandruff, a mild form of seborrheic dermatitis, may be at least partly due to an antifungal activity of tea tree oil.

Histologic Subtyping and Malignancy Assessment of Cutaneous Squamous Cell Carcinoma

Background. Squamous cell carcinomas (SCCs) of the skin have a wide range of histologic subtypes and there are indications of differences in prognosis. Objective. The morphologic variety of SCCs with respect to its biological behavior and the further course of disease is analyzed, with emphasis on histopathologic criteria, briefly quoting the main clinical and pathogenetic aspects. Methods. Referring to the international tumor classification of the World Health Organization, histologically different carcinoma variants are presented and discussed, based on a review of the literature regarding each subtype, and also including the desmoplastic SCC type. Results. Histologically, common invasive SCCs are most frequently found, while metastases mainly occur in tumors of high thickness and poor differentiation. The immature spindle cell carcinoma type resembles sarcoma and may grow rapidly with an aggressive clinical course. Lymphoepithelioma‐like carcinoma of the skin is extremely rare and its histogenesis remains to be elucidated. Thus far, one case with metastasis and lethal outcome has been reported. As details determining the progression ability have so far only been scanty and partially contradictory, more investigations are necessary, especially for acantholytic SCCs and invasive SCCs developing from Bowens disease, whereas verrucous carcinomas can be categorized as low malignancy neoplasms. Desmoplastic SCCs, especially with large tumor thickness, should be separated from other SCC subtypes due to their high risk of local recurrence and metastatic spread. Conclusion. The future outcome of SCCs of the skin is significantly influenced by their histologic grade and tumor thickness. In addition, subtyping represents another valuable histopathologic tool for improving the assessment of malignancy.

Human Thy-1 (CD90) on Activated Endothelial Cells Is a Counterreceptor for the Leukocyte Integrin Mac-1 (CD11b/CD18)

Leukocyte recruitment in response to inflammatory signals is in part governed by interactions between endothelial cell receptors belonging to the Ig superfamily and leukocyte integrins. In our previous work, the human Ig superfamily glycoprotein Thy-1 (CD90) was identified as an activation-associated cell adhesion molecule on human dermal microvascular endothelial cells. Furthermore, the interaction of Thy-1 with a corresponding ligand on monocytes and polymorphonuclear cells was shown to be involved in the adhesion of these leukocytes to activated Thy-1-expressing endothelial cells. In this study, we have identified the specific interaction between human Thy-1 and the leukocyte integrin Mac-1 (CD11b/CD18; αMβ2) both in cellular systems and in purified form. Monocytes and polymorphonuclear cells were shown to adhere to transfectants expressing human Thy-1 as well as to primary Thy-1-expressing human dermal microvascular endothelial cells. Furthermore, leukocyte adhesion to activated endothelium as well as the subsequent transendothelial migration was mediated by the interaction between Thy-1 and Mac-1. This additional pathway in leukocyte-endothelium interaction may play an important role in the regulation of leukocyte recruitment to sites of inflammation.

[Causative agents of onychomycosis--a retrospective study].

Background: Dermatophytes, yeasts and moulds all are potential causative agents of onychomycosis.The aim of this study was to determine the percentage of cases of onychomycoses caused by each group. In addition, the responsible genus and species was identified for each nail infection.

The monoclonal antibody AS02 recognizes a protein on human fibroblasts being highly homologous to Thy-1

Abstract Recently, we described a novel fibroblast-restricted monoclonal antibody (mAb AS02) that recognizes a membrane-bound antigen. Characterization and isolation of the corresponding antigen showed that mAb AS02 recognized a protein on human fibroblasts that is highly homologous or identical to human Thy-1 antigen (CD90). Partial amino acid sequencing of the corresponding mAb AS02 antigen and comparison with known proteins revealed a 100% homology of the sequenced peptides to the human Thy-1 antigen. Cross-immunodepletion studies with mAb AS02 and an anti-Thy-1 antibody confirmed these results. Utilizing two-dimensional (2D) gel electrophoresis of fibroblast cell extracts and purified antigen, mAb AS02 and the anti-Thy-1-antibody recognized identical protein spots. Furthermore, we demonstrated many identical biochemical properties of the corresponding AS02 antigen and Thy-1 antigen, such as the molecular weight of the core protein and deglycosylation products and the detection of a GPI anchor. In functional assays, the attachment of fibroblasts to collagen I and fibronectin was increased after incubation of fibroblasts with mAb AS02. Therefore, the Thy-1 antigen appears to be involved in the regulation of the adherence of human dermal fibroblasts.

Interaction of human Thy-1 (CD 90) with the integrin alphavbeta3 (CD51/CD61): an important mechanism mediating melanoma cell adhesion to activated endothelium

The expression of the αvβ3 integrin (CD51/CD61) on human melanoma cells has been shown to be associated most closely with tumor progression and metastases formation in melanoma. Here, we demonstrated a specific interaction of the αvβ3 integrin on melanoma cells with the human Thy-1, an inducible cell adhesion molecule expressed on the cell surface of activated endothelial cells (EC). The interaction was shown by the binding of purified Thy-1 protein to αVβ3 transfected cells, to αvβ3-expressing melanoma cells and to purified αVβ3 integrin. Moreover, melanoma cells adhere specifically to Thy-1 transfectants via αvβ3 on melanoma cells showing the functional relevance of this interaction for cell adhesion. Finally, the importance of the αvβ3/Thy-1 interaction for the adhesion of melanoma cells to the activated endothelium was confirmed under static and flow conditions by the inhibition of melanoma cell adhesion to and transmigration across activated EC by blocking the αvβ3/Thy-1 interaction. In conclusion, we have identified a new pair of adhesion molecules Thy-1 and αvβ3 mediating the interaction of melanoma cells and activated EC. These data explain at least in part the high tumorigenicity of αvβ3-expressing melanoma cells and the association of αvβ3-positive melanoma cells with a high risk of metastasis and poor prognosis.

Methotrexate in psoriasis: 26 years’ experience with low-dose long-term treatment

Objective To evaluate the efficacy, safety and side‐effects of methotrexate (MTX) in psoriasis.

Detection of human soluble Thy-1 in serum by ELISA. Fibroblasts and activated endothelial cells are a possible source of soluble Thy-1 in serum.

Abstract. The functions of Thy-1, a 35-kDa cell-surface glycoprotein, and its natural ligand are still unknown. Anchoring to the membrane via linkage to phosphatidylinositol (PI) raises the possibility of cleavage off the membrane by PI-specific phospholipases. Soluble Thy-1 (sThy-1) could interfere with the binding of the unknown natural ligand followed by regulation of different cell functions. In this study we established an enzyme-linked immunosorbent assay (ELISA) to measure and quantify sThy-1 in serum and wound fluid. Recombinant human Thy-1 (rhThy-1) was expressed in Drosophila S2 cells, purified from culture supernatant and used as standard for quantitation of sThy-1 by the ELISA technique. There were no differences in sThy-1 levels in serum of healthy donors and patients with systemic sclerosis, leg ulcers, or rheumatoid arthritis, respectively, detected by ELISA. In contrast, at the local site of inflammation, in wound fluid of venous leg ulcers and in synovial fluid from joint puncture, we found strongly elevated levels of sThy-1 compared with sThy-1 in the serum of the same patient. Thy-1 is expressed in humans on brain cells, fibroblasts, a subpopulation of CD34+ blood stem cells, and possibly activated human dermal microvascular endothelial cells. In this study, we never found Thy-1 mRNA or protein expression in resting endothelial cells as shown by reverse transcriptase polymerase chain reaction (RT-PCR) and flow-cytometry. Thy-1 expression could be induced on endothelial cells by phorbol myristate acetate and to a lesser extent by tumor necrosis factor-α (TNF-α). In situ, monoclonal antibodies to Thy-1 did not stain endothelial cells in normal skin, whereas endothelial cells in the synovial membrane of rheumatoid arthritis patients and endothelial cells surrounding melanoma express Thy-1. In summary, our data indicate that Thy-1 is present in soluble form in serum. Furthermore, Thy-1 seems to be a marker for endothelial cell activation. Therefore, activated endothelial cells as well as fibroblasts might be a possible source of sThy-1.

Squamous cell carcinoma of the skin - histopathological features and their significance for the clinical outcome

Background Owing to the rising incidence of tumours, the question of reliable risk classification is becoming increasingly significant.

The fibroblast-specific MAb AS02: a novel tool for detection and elimination of human fibroblasts.

Abstract. The unwelcome presence of fibroblasts in many cell cultures prevents the long term cultivation of various cell types and work with pure populations. Recently, we described a novel fibroblast-specific monoclonal antibody (MAb AS02) that recognises a membrane-bound antigen. We have now developed a method using the fibroblast-specific MAb AS02 immobilised on goat-anti-mouse-magnetic beads to separate contaminating fibroblasts. An endothelial cell line experimentally contaminated with 5%–50% fibroblasts was successfully purified. Additionally, an endothelial cell line with an initial fibroblast contamination of 1.5% was prepared. A proportion of each preparation was cultured with no separation step being performed, whereas the remainder was cultured after purification with MAb AS02 to exclude the presence of a minor number of fibroblasts (<0.1%). The proportion of fibroblasts increased up to 38% in the fifth passage of culture without elimination of the low initial fibroblast contamination, whereas in the fraction with the separation step, no fibroblasts were detectable by flow cytometry, even after the fifth passage. We also used the antibody to detect the presence of naturally contaminating fibroblasts in thyrocyte cultures. After cultivation of thyrocyte cultures over five passages, the number of fibroblasts increased dramatically up to 50%–80% of the whole population. Subsequently, we successfully applied the method for complete elimination of naturally contaminating fibroblasts from freshly isolated thyrocyte cultures from enzymatically digested thyroid glands. Thus, MAb AS02 is a fibroblast-specific marker that is a useful tool for the detection and elimination of contaminating fibroblasts. The specificity of MAb AS02 permits the universal application of this antibody for human cell cultures of interest.