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Ex Vivo Human Skin (ex + vivo_human_skin)
Selected AbstractsAn immunohistological study of anhydrous topical ascorbic acid compositions on ex vivo human skinJOURNAL OF COSMETIC DERMATOLOGY, Issue 2 2006Geoffrey K Heber MBBS Summary Background, Ascorbic acid has numerous essential and beneficial functions in normal and photoaged skin. Ionisation of ascorbic acid in aqueous topical formulations leads to oxidative degradation. Ascorbic acid in an anhydrous vehicle would inherently have greater stability. Objective, The objective of this study was to observe the effects of two anhydrous formulations containing microfine particles of ascorbic acid on neocollagenesis and cytokeratin production in ex vivo human skin. Methods, Vitamin C preparations were applied topically onto the surface of freshly excised human abdominal skin. Following an exposure time of 48 h with appropriate controls, skin discs were cut into sections, placed on slides and assessed using immunohistochemical (antibodies: collagen type I, III, cytokeratin) staining. Analysis was performed using microscopy and descriptive rating. Results, Both formulations resulted in increased production of collagen types I and III and cytokeratin. Conclusion, The application of anhydrous formulations containing microfine particles of ascorbic acid to ex vivo human skin in this study resulted in neocollagenesis and increased production of cytokeratin. This approach appears to enable biological effects of ascorbic acid in the skin using a vehicle which would provide it greater stability than an aqueous vehicle. [source] Ex vivo histological characterization of a novel ablative fractional resurfacing device,LASERS IN SURGERY AND MEDICINE, Issue 2 2007Basil M. Hantash MD Abstract Background and Objectives We introduce a novel CO2 laser device that utilizes ablative fractional resurfacing for deep dermal tissue removal and characterize the resultant thermal effects in skin. Study Design/Materials and Methods A prototype 30 W, 10.6 µm CO2 laser was focused to a 1/e2 spot size of 120 µm and pulse duration up to 0.7 milliseconds to achieve a microarray pattern in ex vivo human skin. Lesion depth and width were assessed histologically using either hematoxylin & eosin (H&E) or lactate dehyrdogenase (LDH) stain. Pulse energies were varied to determine their effect on lesion dimensions. Results Microarrays of ablative and thermal injury were created in fresh ex vivo human skin irradiated with the prototype CO2 laser device. Zones of tissue ablation were surrounded by areas of tissue coagulation spanning the epidermis and part of the dermis. A thin condensed lining on the interior wall of the lesion cavity was observed consistent with eschar formation. At 23.3 mJ, the lesion width was approximately 350 µm and depth 1 mm. In this configuration, the cavities were spaced approximately 500 µm apart and interlesional epidermis and dermis demonstrated viable tissue by LDH staining. Conclusion A novel prototype ablative CO2 laser device operating in a fractional mode was developed and its resultant thermal effects in human abdominal tissue were characterized. We discovered that controlled microarray patterns could be deposited in skin with variable depths of dermal tissue ablation depending on the treatment pulse energy. This is the first report to characterize the successful use of ablative fractional resurfacing as a potential approach to dermatological treatment. Lasers Surg. Med. 39:87,95, 2007. © 2007 Wiley-Liss, Inc. [source] | ||||||||||