M. Stücker

Histomorphologic correlation with routine histology and optical coherence tomography

Background: Optical coherence tomography (OCT) is a new and promising diagnostic technique for investigation of skin tumours. We describe a method that makes evaluation and definition of specific morphologic structures of skin tumours via OCT more accurate.

The cutaneous uptake of atmospheric oxygen contributes significantly to the oxygen supply of human dermis and epidermis

It has been known since 1851 that atmospheric oxygen is taken up by the human epidermis. The contribution to total respiration is negligible. Until now the significance for the local oxygen supply of the skin has remained unknown. With a newly developed sensor, the oxygen fluxoptode, it has become possible to make local measurements of the transcutaneous oxygen flux (tcJO2). In this study the sensor was calibrated so that absolute values of tcJO2 could be reported. At rest, tcJO2 was determined on normal, humidified skin on the volar forearm of 20 volunteers of different age groups. In order to evaluate the contribution of the blood flow to the oxygen supply of the skin, tcJO2 was recorded at the end of a 5 min suprasystolic occlusion of the forearm. At normal skin surface partial oxygen pressure (163 ± 9 Torr), tcJO2 was 0.53 ± 0.27 ml O2 min−1 m−2. A 5 min interruption of blood flow resulted in an increase of 9.5 ± 6.3 % in tcJO2. The value of tcJO2 was unaffected by the age of the subject. Published data on the oxygen diffusion properties of skin and simulations of intracutaneous profiles of oxygen partial pressure indicated that under these conditions, the upper skin layers to a depth of of 0.25–0.40 mm are almost exclusively supplied by external oxygen, whereas the oxygen transport of the blood has a minor influence. As a consequence, a malfunction in capillary oxygen transport cannot be the initiator of the development of superficial skin defects such as those observed in chronic venous incompetence and peripheral arterial occlusive disease.

Anal carcinoma in human immunodeficiency virus-positive men: results of a prospective study from Germany

Background  Anal intraepithelial neoplasia (AIN), a human papillomavirus (HPV)‐associated potential precursor lesion of anal cancer, is frequent among human immunodeficiency virus (HIV)‐positive men who have sex with men (MSM). There is a paucity of data published on the progression of high‐grade AIN to invasive cancer as well as on clinical and virological characteristics comparing anal margin and anal canal carcinoma.

Investigation of basal cell carcionoma by confocal laser scanning microscopy in vivo

Background/purpose In vivo confocal laser scanning microscopy (CLSM) allows to study human skin up to 200 µm deep non‐invasively. Aim of this study was to investigate basal cell carcinoma (BCC) using in vivo CLSM, and to compare the micromorphologic features of BCC with uninvolved skin.

Imiquimod leads to a decrease of human papillomavirus DNA and to a sustained clearance of anal intraepithelial neoplasia in HIV-infected men.

Anal intraepithelial neoplasia (AIN), a human papillomavirus (HPV)-associated precursor lesion of anal carcinoma, is highly prevalent in HIV-infected men having sex with men (MSM). This prospective follow-up study evaluated the long-term results of imiquimod treatment of AIN in 19 HIV-infected MSM. Standardized follow-up examinations included high-resolution anoscopy, anal cytology/histology, HPV typing, and DNA load determination for HPV types 16, 18, 31, and 33. Mean follow-up time was 30.3 months. A total of 74% (14/19) of the patients remained free of AIN at the previously treated site. Five patients (26%) had recurrent high-grade AIN after a mean time of 24.6 months. At the end of follow-up, the numbers of HPV types as well as high-risk HPV-DNA loads were significantly lower than before therapy. During follow-up, 58% of all patients (11/19) developed new anal cytological abnormalities in previously normal, untreated anal regions. 55% of these new AIN lesions were high-grade lesions and most of them were located intra-anally and associated with high-risk HPV types not detectable before therapy. These results demonstrate that imiquimod leads to a high rate of long-term clearance of AIN in HIV-positive men together with a prolonged decrease of high-risk HPV-DNA load. However, new AIN lesions associated with previously undetected HPV types frequently occur in untreated areas.

Guidelines for visualization of cutaneous blood flow by laser Doppler perfusion imaging

This report reviews how to set up a laser Doppler perfusion imaging system intended for visualization of skin blood perfusion, capture images and evaluate the results obtained. A brief summary of related papers published in the literature within the areas of skin irritant and allergy patch testing, microdialysis and skin tumour circulation is presented, as well as early applications within other fields such as diabetology, wound healing and microvascular research.

Fluorescence Studies of Melanin by Stepwise Two-Photon Femtosecond Laser Excitation

Fluorescence of synthetic melanin in the solvents H2O, KOH, ethylene glycol monomethyl ether, and dimethyl sulfoxide has been excited by two-photon absorption at 800 nm, using 120-fs pulses with photon flux densities of ≥1027 cm−2.S−1. Compared to the one-photon (400-nm)-induced fluorescence of melanin, the overall spectral shape is red-shifted and shows a strong environment sensitivity. The decay of the two-photon-induced fluorescence (TPF) of melanin is three-exponential, with a shortest main component of about 200 ps. The results of the TPF studies in line with the unique light absorption property of melanin of a monotonously decreasing absorption spectrum between the near UV-region and the near infrared region indicate that the TPF is realized via stepwise absorption of two 800-nm photons. In comparison to the simultaneous absorption of two photons, the stepwise process needs lower photon flux densities to get a sufficient population of the fluorescent level. This stepwise process offers new possibilities of selective excitation of melanin in skin tissue in a spectral region where there is no overlap with any absorption of another fluorescent tissue component. The first results with different samples of excised human skin tissue (healthy, nevus cell nevi, malignant melanoma) suggest that fluorescence excited in this way yields information on malignant transformation.

Femtosecond two-photon excited fluorescence of melanin.

Abstract. Fluorescence of synthetic melanin in dimethyl sulfoxide has been excited by two‐photon absorption at 800 run, using 120 fs pulses with photon flux densities 1027 cm 2 s1. The shortest main component of the three‐exponential decay of fluorescence is 200 ± 2 ps. The overall spectral shape is red‐shifted with respect to the 400 nm excited fluorescence. Two‐photon excited melanin fluorescence also has been measured from excised samples of healthy human skin tissue. Because of the selectivity of melanin excitation via resonant two‐photon absorption, it is hypothesized that fluorescence excited in this way may yield information on malignant transformation.

Guidelines for visualization of cutaneous blood flow by laser Doppler perfusion imaging. A report from the Standardization Group of the European Society of Contact Dermatitis based upon the HIRELADO European community project.

This report reviews how to set up a laser Doppler perfusion imaging system intended for visualization of skin blood perfusion, capture images and evaluate the results obtained. A brief summary of related papers published in the literature within the areas of skin irritant and allergy patch testing, microdialysis and skin tumour circulation is presented, as well as early applications within other fields such as diabetology, wound healing and microvascular research.

Fumaric acid esters in necrobiosis lipoidica: results of a prospective noncontrolled study

Background  Necrobiosis lipoidica (NL) is an uncommon granulomatous skin disease with association to diabetes mellitus. To date, no proven effective therapy for NL has been implemented. The standard treatment is topical application of corticosteroids, but numerous agents have been reported for NL, with varying degrees of success. In recent case reports, fumaric acid esters (FAE) have been reported to be effective in granulomatous skin diseases such as granuloma annulare, cutaneous sarcoidosis and NL.