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Notes: Background/purpose:  Sulphur mustard (SM) is a potent incapacitating chemical warfare agent that remains a threat to war fighters and civilians worldwide. SM lesions may require weeks or months to heal, depending upon their severity. This study was undertaken to find a treatment regimen that promotes speedier healing of deep cutaneous SM burns in a weanling pig model. The principal objective of the study was to compare four treatment regimens and establish which achieved the shortest healing time.Methods:  Twelve Yorkshire Cross weanling pigs were exposed to SM liquid for 2 h, generating six large deep dermal/full thickness burns on the ventrum of each animal. Three additional animals served as sham-exposed controls. Surgical intervention occurred at 48 h postexposure. Treatments included: (i) full-thickness debridement of the burns with a computer controlled, raster scanned continuous wave CO2 laser followed by autologous split-thickness skin grafting; (ii) full-thickness sharp surgical tangential excision followed by skin grafting, the ‘Gold Standard’ used in human deep dermal/full-thickness thermal burns management; (iii) partial-thickness laser ablation with no grafting; and (iv) partial-thickness sharp surgical excision with no grafting. Several non-invasive bioengineering methods were used to monitor the progress of wound healing throughout a 36-day healing period: reflectance colourimetry, evaporimetry, laser Doppler perfusion imaging and ballistometry.Results:  Bioengineering methods indicated that laser debridement followed by autologous split-thickness skin grafting was as efficacious in improving the wound healing of deep SM burns in weanling swine as the ‘Gold Standard.’ Regardless of the method of debridement, barrier function, skin colour and mechanical properties returned to near-normal levels within 15 days of treatment in the grafted sites. Regardless of surgical approach, blood flux levels remained approximately 50–60% of normal tissue throughout the 36-day postsurgical observation period. Mid-dermal debridement by sharp surgical tangential excision or laser ablation without the use of skin grafts did not produce as good a result as those attained through the use of grafts, but was better than no surgical treatment of the wounds.Conclusion:  Bioengineering methods were useful in evaluating multiple characteristics during wound healing: (i) reflectance colourimetry for skin colour, (ii) evaporimetry to measure transepidermal water loss as an indicator of barrier function, (iii) laser Doppler perfusion imaging to assess cutaneous blood flow, and (iv) ballistometry to measure the mechanical properties of skin hardness and elasticity. Perhaps the most useful method was evaporimetry, as a restored barrier function was the best indicator of healed wounds. The use of reflectance colourimetry and ballistometry will continue in future wound healing studies for their contributions in judging cosmetic and functional outcomes. While useful, laser Doppler perfusion imaging was found to be rather time consuming. This methodology will be limited in the future to burn depth estimation prior to treatment, and for evaluation of pharmaceuticals specifically designed to improve or sustain blood flow into damaged areas.

Notes: We investigated the kinetics of hydrochloric acid demineralization of human cortical bone with the objective of developing a method of controlled demineralization for structural bone allografts. It is known that the demineralization of cortical bone is a diffusion rate limited process with a sharp advancing reaction front. The demineralization kinetics of human cortical bone, described as the advance of the reaction front versus immersion time, were determined by measuring extraction of bone mineral in both planar and cylindrical geometries. Mathematical models based on diffusional mass transfer were developed to predict this process. The experimental data fit well with the behavior predicted by the model. The model for planar geometry is applicable to controlled demineralization of cortical bone allografts of irregular shapes such as cortical struts. The model for cylindrical geometry is appropriate when curved surfaces are involved such as in diaphyseal bone allografts. This method of demineralization has direct application to clinical modification of cortical bone allografts to potentially enhance their osteoinductive properties. © 1996 John Wiley & Sons, Inc.