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Abstract

digital image speckle correlation (DISC) algorithm to assess burn scar thickness and contraction zone. DISC tracks the movement of skin pores or other fine structures as the result of an applied force on the skin. Requiring simple digital photographs, DISC is capable of providing noninvasive quantitative measurements of scar contracture and thickness. Here we demonstrate DISC tracking of burn scars using a validated vertical progression porcine burn model. MATERIAL AND METHODS: Twenty 2.5cmx2.5cm burns were created on the dorsum of four female swine using an aluminum bar. Three burn temperatures and exposure times have been shown in prior studies to create distinct burn depths -70°C for 30 seconds, 80°C for 20 seconds, and 80°C for 30 seconds. DISC images were taken 4 weeks post burn using a high resolution camera oriented perpendicular to the wound bed. Pig respiration was used as an applied variable force, and vector maps were created using an algorithm that measures the displacement of multiple pores on the skin surface over the course of respiration. RESULTS: Deep dermal wounds were found to display nearly symmetric vector forces targeting a very small diameter area in the center of the wound bed, while more superficial wounds displayed irregular vector dynamics with no trend towards a center. Flank wounds and wounds above the rib cage were found to display more symmetric forces, correlating with increased contraction as compared to paramedian and caudal wounds. These observations were confirmed by clinical measurements. CONCLUSIONS: DISC illustrates that symmetric and unified forces within a wound bed can be associated with significant contraction. The diameter of the center of the force vector appears to correlate with the degree of burn contraction observed clinically. DISC presents a novel methodology for quickly and reliably highlighting zones of skin contracture, allowing for ideal aesthetic and mobility outcomes without the need for unnecessary revisions. INTRODUCTION:Bone tissue engineering as well as physiological bone regeneration demand an adequate vascularization. Furthermore manifold studies reveal that cocultivation of human primary osteoblasts (hOBs) with endothelial cells (ECs) influences cell physiology of hOBs e.g osteogenic differentiation. This study intended to enlighten the specific interactions between hOBs and ECs concerning proliferation and apoptosis. MATERIALS AND METHODS:The proliferation rate was quantified after 1,3,5,and 7 days. Apoptosis was investigated by DNA fragmentation ELISA and phospho-BAD ELISA. To differentiate between effects due to heterotypic cell contacts or paracrine mediators, direct and indirect cocultures of hOBs and HUVECs were performed. RESULTS: After 7 days of direct cocultivation, the proliferation rate of hOBs showed a 3,7 fold increase in comparison to the hOBs in monoculture (p<0,005). Interestingly proliferation of cocultured ECs' remained unvaried. Beyond that EC significantly (p<0,05) reduced apoptosis of hOBs in direct as well as in indirect cocultu...