Tissue viability (TiVi) imaging: temporal effects of local occlusion studies in the volar forearm.

Tissue Viability (TiVi) imaging is a promising new technology for the assessment of microcirculation in the upper human dermis. Although the technique is easily implemented and develops large amounts of observational data, its role in the clinical workplace awaits the development of standardised protocols required for routine clinical practice. The present study investigates the use of TiVi technology in a human, in vivo, localized, skin blood flow occlusion protocol. In this feasibility study, the response of the cutaneous microcirculation after provocation on the volar surface of the forearm was evaluated using a high temporal-low spatial resolution TiVi camera. 19 healthy subjects - 10 female and 9 male - were studied after a localized pressure was applied for 5 different time periods ranging from 5 to 25 seconds. Areas corresponding to 100 x 100 pixels (2.89 cm(2)) were monitored for 60 seconds prior to, during and after each occlusion period. Our results demonstrated the removal of blood from the local area and a hyperaemic response supporting the suitability of TiVi imaging for the generation of detailed provocation response data of relevance for the physiological function of the skin microcirculation in health and disease.

Porcine ear skin: an in vitro model for human skin.

BACKGROUND/PURPOSE: Porcine ear skin is used in studies of percutaneous penetration as a substitute for human skin. The structure of this tissue, including hair follicles, was studied qualitatively and quantitatively in comparison with human skin. METHODS: Sections of shock-frozen biopsies, biopsies embedded in paraffin and cyanoacrylate skin surface biopsies were investigated using microscopy. The thickness of the different skin layers and the follicular characteristics were determined. RESULTS: The thickness of the stratum corneum was 17-28 microm, whereas the viable epidermis was 60-85 microm thick. On 1 cm(2), 11-25 hairs were detected, showing a diameter of 58-97 microm and a maximal extension depth of 0.96-1.38 mm into the skin. The orifices of the porcine infundibula showed a diameter of approximately 200 microm. CONCLUSIONS: The results obtained are similar to those of human skin, indicating the suitability of this porcine tissue as a model for human skin.