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Abstract: Mammalian target of rapamycin (mTOR) is an important mediator for cross talk between nutritional signals and metabolic signals of insulin by downregulating insulin receptor substrate proteins. Therefore, mTOR inhibition could become a therapeutic strategy in insulin-resistant states, including insulin resistance induced by burn. We tested this hypothesis in the rat model of 30% TBSA full thickness burn, using the mTOR inhibitor rapamycin. Rapamycin (0.4mg/kg, i.p.) was injected 2h before euglycemic–hyperinsulinemic glucose clamps at 4 days after burn. IRS-1, phospho-serine307, phospho-tyrosine of IRS-1 and phospho-mTOR in muscle tissue were determined by immunoprecipitation and Western blot analysis or immunohistochemistry. Plasma TNF-α, insulin and C-peptide were determined before and after euglycemic–hyperinsulinemic glucose clamps. Our data showed that TNF-α, insulin and C-peptide significantly increased in the early stage after burn (P <0.01). The infused rates of total 10% glucose (GIR, mg/kgmin) significantly decreased at 4 days after burn. The level of IRS-1 serine307 phosphorylation in muscle in vivo significantly increased after burn (P <0.01), while insulin-induced tyrosine phosphorylation of IRS-1 significantly decreased (P <0.01). Inhibition of mTOR by rapamycin inhibited the phosphorylation of mTOR, reduced serine307 phosphorylation, elevated tyrosine phosphorylation and partly prevented the decrease of GIR after burn. However, TNF-α, insulin and C-peptide were not decreased by rapamycin treatment postburn. Taken together, these results indicate that the mTOR pathway is an important modulator of the signals involved in the acute regulation of insulin-stimulated glucose metabolism, and at least, partly contributes to burn-induced insulin resistance. mTOR inhibition may become a therapeutic strategy in insulin-resistant states after burn. [Copyright &y& Elsevier]

Burn wound excision and grafting is a common clinical practice that decreases patient morbidity and mortality. It is not known, however, if the salutary effects of this procedure are related to effects on interleukin 6 (IL-6) and tumor necrosis factor (TNF-) α, and to reducing insulin resistance after burn. Sprague–Dawley rats were randomly divided into three groups: control, burn, burn±excision groups. Rats in burn group were given a third-degree scald burn covering 30% total body surface area (TBSA) and no wound excision. Rats in burn±excision group were subjected to a 30% third-degree burn followed by complete excision and allografting of the injury site within 15min after burn. The rats in control group were treated in the same manner as the burn group, except that they were immersed in a room-temperature water. Glucose tolerance tests (GTT) were observed at 3 days after burn, euglycemic–hyperinsulinemic glucose clamps were performed at 4 days after burn and interleukin 6 (IL-6) and tumor necrosis factor (TNF-) α were determined after euglycemic–hyperinsulinemic glucose clamps. The levels of IL-6 and TNF-α increased after burn. Significant differences in GTT were observed between control and burn groups, and the rate of glucose infused measured in burned rats was significantly decreased compared with that in control at 4 days after burn. Early excision and grafting significantly decreased levels of IL-6 and TNF-α, and further reduced insulin resistance following thermal injury compared with burn group. Conclusion: Early excision and grafting appeared to have an effect on inflammatory mediators and further reduced insulin resistance induced by major burns. [Copyright &y& Elsevier]

Abstract: Objective: To reveal the characteristic and distribution of length of hospital stay (LOS) and direct hospitalisation costs of paediatric scald. Methods: A prospective case series observation was performed from January 2005 to December 2006 at the Burn Center, Changhai Hospital, Shanghai, China. The information, such as demographics, clinical diagnosis and treatments since admission, of the paediatric scald patients included in the series was recorded. The direct cost of a treatment event was recorded into the price system when it was incurred. All cost data were summarised on completion of the study. The distribution of LOS and the hospitalisation costs were recorded by gender, age, total burn area, depth of burn, blood transfusion and patterns of treatment. Mann–Whitney signed-rank test was used to assess the differences between continuous, non-normally distributed variables, and multiple linear regression was used to model LOS and direct hospitalisation costs. Statistical analyses were undertaken with SPSS 15.0 statistical software. Results: Patients aged 3 years or less accounted for more than half of the total LOS and hospitalisation costs, patients with burn area less than 10%TBSA (total burn surface area) accounted for more than 70% of the total LOS and more than half of the hospitalisation costs and patients with second-degree burn accounted for more than 78% of the total LOS and hospitalisation costs. Depth of burn, area of burn, patterns of treatment and blood transfusion were independent predictors of LOS; whereas LOS, area of burn and blood transfusion were independent predictors of hospitalisation costs. Conclusion: Paediatric scalds have particular characteristics in terms of distribution of LOS and direct hospitalisation costs and the factors influencing them. The data presented in this study should assist burn care practitioners and hospital epidemiologists estimate and compare the economic burden of paediatric burns at other institutions; it may also be useful in resource allocation and cost-effectiveness analysis of treatment versus prevention strategies. [Copyright &y& Elsevier]