[Effects of topical application of insulin on the wound healing in scalded rats].

OBJECTIVE: To investigate the effects of topical application of small dose of insulin on the wound healing of the scalded rats, so as to explore its mechanism. METHODS: The rats employed in the study were subjected to deep partial thickness burn and were divided into group A (with subcutaneous injection of isotonic saline into the rat wounds as control), B and C (with subcutaneous injection of 0.1 U and 1 U insulin in the rat wounds respectively) and D (with subcutaneous injection of 0.1 U insulin in the rat abdomen as control). The wound healing time and wound healing rate were assessed every other day after 3 postburn days (PBDs). The histological changes of the wounds after injection were examined, the changes in the cell cycle of epidermal cells in the wound were analyzed by flow-cytometry, and blood glucose concentration of each group was determined. RESULTS: The wound healing time in group B (18.36 +/- 4.12 d) was significantly shorter than that in other groups (A: 24.57 +/- 5.19 d, C: 21.46 +/- 2.97 d, D: 24.50 +/- 1.05 d, P < 0.01). The wound healing rate of the rats in group B in 5, 9, 11, 13, 15, 17 and 19 PBD was obviously higher than that in group A, and was markedly higher than that in group C on 17 PBD (P < 0.05 - 0.01). The epithelial layer was thinner with less epidermal nails but much more fibroblasts in epidermal layer in group A, while the epithelial layer was thicker with abundant epidermal nails in group B and C with many fibroblasts in the dermis. The amount of cells in S phase at 4 PBD in group B was dramatically higher than that in group A, and cells in G2M phase at 4 - 5 PBD in group B was also higher than that in group A and C (P < 0.05 - 0.01). The blood level of glucose in group A and B fluctuated between 3.42 to 4.62 mmol/L at 24 PBH, while that in group C and D decreased obviously 1 hour after injection (P < 0.01), but gradually returned to normal 4 hours after injection. CONCLUSION: Local injection of small dose of insulin may accelerate burn wound healing due to its role in promoting the proliferation and division of the repairing cells.

[Initiation of systemic administration of antibiotics in treatment of invasive infection of burns].

OBJECTIVE: To optimize the systemic antibiotics in the treatment of the invasive infection of burns based on the successive monitoring of bacterial species harvested from the burn wound and subeschar tissues and their resistance to antibiotics. METHODS: The data of bacteriological monitoring of burn wound and subeschar tissues in our burn center from 1995 to 2000 were retrospectively analyzed, and the characteristics of distribution and resistance to antibiotics of 1 109 strains from the wound in 612 patients and subeschar tissues in 146 patients were compared statistically by dividing them into two periods, i.e. from 1995 to 1997 and 1998 to 2000, respectively. RESULTS: The percentage of Gram negative bacilli in identified strains was significantly higher than that of Gram positive cocci, and the majority of them were Pseudomonas and Enterobacteriaceae; Staphylococcus aureus comprised the majority of Gram positive cocci from 1998 to 2000, compared with the data collected in the period of from 1995 to 1997. The resistance of the Gram negative bacilli to Cephalosporins and Amikacin was increasing while the resistance of Pseudomonas to Netilmicin was decreasing from 18.52% of the tested strains down to 5.83%, and the resistance of Enterobacteriaceae to it was increasing from 18.75% to 55.79%. In addition, the resistance of Staphylococcus aureus to Netilmicin was down from 28.13% to 4.70%. Enterobacteriaceae were still sensitive to Imipenem, while the resistance of Pseudomonas to it became higher than that in the period from 1995 to 1997. CONCLUSION: The percentage of Gram negative bacilli in identified strains is significantly higher than that of Gram positive cocci and the pattern of their resistance to the antibiotics is changed meanwhile. Therefore, the choice of antibiotics for initial treatment of invasive infection in severe burns is a combination of Netilmicin and Imipenem, and, if Gram positive cocci is highly suspected, the first choice is Vancomycin.