Fibrin sealant improves graft adherence in a porcine full-thickness burn wound model.

INTRODUCTION: Autograft take and rapid wound closure is essential for the survival of severely burned patients. Loss of skin grafts typically occurs during the first few days after coverage, mainly due to shear forces and inadequate contact with the wound bed. Slow-clotting fibrin sealant, applied with a spray-on device, has been shown to improve healing of skin grafts in large wounds. However, its use in burn wounds has not been studied so far. STUDY AIM: To evaluate the effectiveness of sprayed fibrin sealant in excised and grafted full-thickness burns. MATERIAL AND METHODS: Ten female Yorkshire pigs (30-45 kg) received a full-thickness contact burn of approximately 15% total body surface area. The burns were excised to the level of the muscular fascia after 24 h and covered with meshed skin autograft (mesh ratio 1:3). Wounds were randomized to either fibrin sealant (n=20) or standard skin staples (n=16) for graft fixation. Fibrin sealant was used as a slow-clotting spray (4 IU thrombin/ml). Outcome measurements included clinical scoring at days 2, 5, 9 and 14 postoperatively, planimetric analysis of wound closure, and histological examination of epidermal and dermal thickness 14 days after autografting. RESULTS: In the fibrin sealant group, graft adherence scores were significantly increased (p<0.02) and graft dislocation scores significantly decreased (p<0.01) at days 2 and 5 postoperatively, when compared to controls. Planimetric analysis of remaining open mesh interstices showed acceleration of wound closure in the fibrin sealant group but did not reach statistical significance (day 14 p=0.04 at significance level p<0.025). Wound contraction, occurrence of hematoma, and dermal as well as epidermal thickness were not different between the groups at 14 days postoperatively. CONCLUSION: The results indicate that the use of slow-clotting fibrin sealant spray for autograft fixation is advantageous over skin staples. Easy handling and reduced graft dislocation at early time points are key qualities of this method.

A porcine model of full-thickness burn, excision and skin autografting.

Acute burn wounds often require early excision and adequate coverage to prevent further hypothermia, protein and fluid losses, and the risk of infection. Meshed autologous skin grafts are generally regarded as the standard treatment for extensive full-thickness burns. Graft take and rate of wound healing, however, depend on several endogenous factors. This paper describes a standardized reproducible porcine model of burn and skin grafting which can be used to study the effects of topical treatments on graft take and re-epithelialization. Procedures provide a protocol for successful porcine burn wound experiments with special focus on pre-operative care, anesthesia, burn allocation, excision and grafting, postoperative treatment, dressing application, and specimen collection. Selected outcome measurements include percent area of wound closure by planimetry, wound assessment using a clinical assessment scale, and histological scoring. The use of this standardized model provides burn researchers with a valuable tool for the comparison of different topical drug treatments and dressing materials in a setting that closely mimics clinical reality.

Amnion in the treatment of pediatric partial-thickness facial burns.

BACKGROUND: Wound coverage for second-degree burns remains a clinical challenge. Human amniotic membranes have been used for many years in the treatment of burns; however, no large prospective clinical trials have been published. In this article, we present a novel and standardized procurement and processing method for amnion and investigate, whether the use of this biological dressing is safe and may represent a new therapeutic option for children with partial-thickness facial burns compared to standard topical treatment. METHODS: Patients with partial-thickness burns of the face, neck and head admitted between 2003 and 2005 were included in this study. They were divided into two groups to receive either amnion (n=53) or topical antimicrobials (n=49). Demographics (age, gender, ethnicity, TBSA, burn areas), length of hospital stay (LOS), rate of infections (RI), time to total healing, and frequency of dressing changes were compared between the two groups. The long-term outcome was assessed in nine patients in the amnion group and eight patients in the topical group, who returned for up to 12-month follow-up visits. RESULTS: Patients in the amnion group had significantly less dressing changes then in the control group (p<0.05). Time to healing, length of stay and the development of hypertrophic scarring was not different between the groups. Use of amnion was not associated with an increased risk of local infection. CONCLUSION: This study indicates that amnion is safe and has advantages as wound coverage for second-degree facial burns compared to the standard topical ointments. Further studies with the use of amniotic membranes on the trunk and the extremities, as well as for coverage of grafted third-degree burns, have yet to be performed.

Detoxification of olefinic epoxides and nucleotide excision repair of epoxide-mediated DNA damage: Insights from animal models examining human sensitivity to 1,3-butadiene.

1,3-Butadiene (BD) is a well-documented mutagen and carcinogen in rodents and is currently classified as a probable carcinogen in humans. Studies investigating workers exposed to BD indicate that, in some plants, there may be an increased genetic risk, and that polymorphisms in biotransformation and DNA repair proteins may modulate genetic susceptibility. To investigate the role of genetic polymorphisms in microsomal epoxide hydrolase (mEH) or nucleotide excision repair (NER) in contributing to the mutagenicity of BD, we conducted a series of experiments in which mice lacking mEH or NER activity were exposed to BD by inhalation or to the reactive epoxide metabolites of BD (epoxybutene-EB or diepoxybutane-DEB) by i.p. injection. Genetic susceptibility was measured using the Hprt cloning assay. Both deficient strains of mouse were significantly more sensitive to the mutagenic effects of BD and the injected epoxides. These studies provide support for the critical role that mEH plays in the biotransformation of BD, and the role that NER plays in maintaining genomic integrity following exposure to BD. Additional studies are needed to examine the importance of base excision repair (BER) in maintaining genomic integrity, the differential formation of DNA and protein adducts in deficient strains, and the potential for enhanced sensitivity to BD genotoxicity in mice either lacking or deficient in both biotransformation and DNA repair activity.