[Good clinical practice. Its meaning for clinical research].
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Clinical Trials as Topic↗
Biomedical subjects
T W Fischer
Publications and source records attributed to T W Fischer.
Non-immunologic contact urticaria from chrysanthemum confirmed by the CAST method. Complement-activated (C5a) cellular antigen stimulation test.
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Adult↗
Direct and non-direct measurement techniques for analysis of skin surface topography.
Estimation of skin smoothness is of ever-increasing interest especially in the field of cosmetic research. There are some established methods for assessing skin smoothness, e.g. optical and mechanical profilometry, but the presentation of recently developed new methods reflects the demand for alternatives which are more precise and practical. For fundamental research on ultrastructure of the stratum corneum surface scanning electron microscopy is a suitable method. A direct method is the surface evaluation of living skin, which is based on an optical system in a CCD camera measuring four parameters of roughness, scaling, smoothing and wrinkling. A similar but non-direct method is optical profilometry using skin replicas. Laser profilometry produces a variety of data which can be analysed using complex mathematical functions. A promising new method is transparency profilometry (skin visiometer) using a very thin skin print which allows parallel light to pass through and is analysed immediately after production. The different methods can be used for characterization of the skin microrelief in dermatoses or for dynamic measurements of time-dependent changes in skin surface topography after application of cosmetic or medical products.
Clinical Laboratory Techniques↗
Assessment of 'dry skin': current bioengineering methods and test designs.
Dry skin is a frequent problem in dermatology and a sign of dysfunction of the epidermis, especially of the stratum corneum as the morphological equivalent of the skin barrier. It may occur as an individual disposition or as the leading symptom of atopic dermatitis or ichthyosis. Besides the visual examination of the skin, various bioengineering methods have been developed to assess the different pathological and adaptive changes in the skin. In addition to the assessment of skin humidity, barrier function and desquamation, the quantification of skin surface topography and the mechanical properties of skin are suitable methods to characterize a dry skin condition. For clinical assessment of moisturizing products and emollients the parameters of investigation have to be defined and integrated in an adapted study design depending on the composition and content of the active agent in the test product. Newly developed cosmetic products have to be investigated for safety and efficacy. Modern bioengineering methods are suitable to fulfill these challenges.
Animals↗
HaCaT cell proliferation influenced by melatonin.
The hormone melatonin is characterized by numerous pharmacological effects. The influence of melatonin on the growth of the human hair follicle was shown in previous investigations. In the present study, the effects of melatonin were investigated by means of proliferation tests of HaCaT keratinocytes using the [3H]thymidine incorporation, a fluorescence assay with Hoechst dye 33342 and the ATP bioluminescence assay. The aim of the study was to find melatonin concentrations suitable for treatments of the skin and whether there is a cytotoxic effect on HaCaT cells. The different proliferative activity of melatonin depending on its concentration and the time of incubation could be shown in all investigations.
Adenosine Triphosphate↗
Percutaneous penetration of topically applied melatonin in a cream and an alcoholic solution.
In a clinical study, the skin penetration properties of melatonin 0.01% in a cream and 0.01 and 0.03% in a solution were investigated by evaluation of the serum melatonin levels over a 24-hour time course in 15 healthy volunteers. Blood samples for melatonin measurements were taken at 9.00 a.m. before applying the test preparations and 1, 4, 8 and 24 h after application. The measurements were carried out by radioimmunoassay for melatonin. In 15 volunteers, the serum levels of melatonin before application of the topical preparations were between 0.6 and 15.9 pg/ml. After application of the 0.01% melatonin cream, there was a steady increase starting from 9.00 a.m. up to a mean serum value of 9.0 pg/ml at 9.00 a.m. the next day. The solution of 0.01% melatonin also showed an increase, starting from 5.00 p.m., up to a mean melatonin level of 12.7 pg/ml 24 h after application. The solution containing 0.03% melatonin resulted in elevated melatonin levels 1 and 8 h after application. The values were 18.1 and 19.0 pg/ml. The cumulative melatonin values for each preparation were 7.1, 8.6 and 15.7 pg/ml, respectively. This study shows that the strongly lipophilic substance melatonin is able to penetrate through the skin and leads to dose- and galenic-dependent melatonin levels in the blood. No increase of melatonin above the physiological range was observed.
Administration, Cutaneous↗