Spectral Remittance and Transmittance of Visible and Infrared-A Radiation in Human Skin-Comparison Between in vivo Measurements and Model Calculations.

The aim of the study was to assess the interindividual variability of spectral remittance and spectral transmittance of visible and infrared-A radiations interacting with human skin and subcutaneous tissue, and direct measurements were taken in vivo using healthy persons of different skin color types. Up to wavelengths of about 900 nm, both spectral remittance and spectral transmittance depended significantly on the individual contents of melanin and hemoglobin in the skin, whereas the contents of water and lipids mainly determined spectral slopes of both characteristics of interaction for wavelengths above about 900 nm. In vivo measured data of spectral transmittance showed approximately similar decreases with tissue thickness between about 900 nm and 1100 nm as compared with model data which were calculated using spectral absorption and scattering coefficients of skin samples in vitro published by different authors. In addition, in vivo measured data and in vitro-based model calculations of spectral remittance were approximately comparable in this wavelength range. In contrast, systematic but individually varying differences between both methods were found for both spectral remittance and spectral transmittance at wavelengths below about 900 nm, where interaction of radiation was significantly affected by both melanin and hemoglobin.

Randomised controlled trial analysing supplementation with 250 versus 500 units of vitamin D3, sun exposure and surrounding factors in breastfed infants.

BACKGROUND: The rate of non-compliance with vitamin D supplementation is as high as 45%. This is why randomised controlled trials are needed to analyse the response to low doses of vitamin D3. OBJECTIVE: (1) To compare supplementation with 250 versus 500 units of vitamin D3 and (2) to analyse sun exposure time/ultraviolet B (UVB) exposure during the first 6 weeks of life. DESIGN: 40 breastfed infants (skin photo-types I, II) were recruited in Berlin, Germany (52.5°N), during summer (n=20) and winter (n=20) and randomised into equal groups on either 250 or 500 units of vitamin D3 per day. Outcome measures were: parameters of vitamin D and bone metabolism at delivery and 6 weeks later, sun exposure time, UVB dosimetry and surrounding factors including maternal diet. RESULTS: At delivery 25-hydroxy vitamin D levels were insufficient: 68 (53-83) nmol/l in each group. 6 weeks later levels were sufficient: 139 (114-164) nmol/l on 250 units of vitamin D3 per day and 151 (126-176) nmol/l on 500 units/day. There was no seasonal variation. Daily sun exposure time was 0.4-3.5 h and higher in summer. UVB exposure was 0.01-0.08 minimal erythema dose/day. Calcium levels were within normal. CONCLUSIONS: In Berlin, Germany, supplementation with 250 units of vitamin D3 is sufficient for breastfed infants during their first 6 weeks of life in summer and winter. UVB exposure is very low throughout the year.

[Dithranol in the treatment of scalp psoriasis]. / Die Behandlung der Psoriasis capillitii mit Dithranol.

Dithranol in its usual petrolatum base cannot be effectively applied to the scalp. The washable cream base is not often employed in Germany, both because this form of application is not well-known and because the positive effects are underestimated while the adverse effects are overestimated. Therefore we have searched the literature for appropriate studies, application recommendations and reports on side effects. We list scalp preparations containing dithranol available in neighbouring European countries together with recommendations and warning notes. Since the dithranol molecule contains hydrophilic and lipophilic parts, it can be easily incorporated into soaps. The stability of such preparations is limited; their effectiveness is supported by the usage of dithranol in an emulsifying oil base in the Charité Department of Dermatology for more than twenty years. The special vehicle used, bio-wash-oil, is an oily fluid soap which was designed for cleaning the heavily soiled hands of factory workers. It can be easily applied to the scalp and washed off with water. Here we re-examine the original study on dithranol in bio-wash-oil published by Meffert et al. in 1979, summarize our subsequent experience and present a recent comparative study paying special attention to side effects, practical notes, and patient comfort and satisfaction.