82 Burns (1991) Vol. 17/No. 1

Pulsed laser ablation of burned skin Pulsed CO, laser ablation of burned skin has been found to be much more effective than continuous wave laser ablation. The increased power of the pulsed laser allows speedier excision, a much smaller area of thermal damage to the tissues beneath the eschar (85 pm compared with 500-800 pm with a CW CO, laser) and a virtually bloodless wound bed.

The minimal damage to subeschar tissues and the virtually blood free wound should allow optimal ‘take’ of grafted skin alone or its admixture with cultured epidermis.

Green H. A., Domankevitz Y. and Nishioka N. S. (1990) Pulsed carbon dioxide laser ablation of burned skin: in vitro and in vivo analysis. Lasers Surg. Med. 10, 476-484.

PGE, release by Kupffer cells Guinea-pigs with deep burns covering 30 per cent of the body surface area showed significantly increased Kupffer cell release of PGE, following endotoxin stimulation. There was a significant decrease in antibody-dependent cell-mediated cytotoxicity I day after injury. By 8 days after burning Kupffer cells that had been co-cultured with hepatocytes released significantly less PGE,.

Ogle C. K., Wu J. Z., Wood S. et al. (1990) The increased release of prostaglandin E, by Kupffer cells from burned guinea pigs. J, Bum Care Rehabil. 11, (4), 287-294.

Lymph is also immunosuppressive It is already known that both serum and oedema fluid taken from severely burned patients can suppress mitogen-induced lympho- cyte proliferation. In dogs with scalded hind paws it was found that serum, lymph, oedema fluid and tissue fluid from beneath the scalded tissue collected at intervals up to 6 h after scalding were all able to induce prolonged suppression of mitogen-induced lym- phocyte proliferation.

Ferrara J. J., Dyess D. L., Luterman A. et al. (1990) Trans- portation of immunosuppressive substances produced at the site of burn injury into the systemic circulation: the role of lymphatics. J. Bum Care Rehabil. 11, (4), 281-286.

Cytomegalovirus and bacterial translocation Two strains of mice were infected with cytomegalovims, some of which also received scalds covering about 15 per cent of the body surface area. Other mice were only scalded. Mesenteric lymph nodes were cultured from all the mice.

There was an increased incidence of positive lymph node cultures from the virus-infected scalded mice compared with the

other groups. No intestinal mucosal histologies, mucosal dry weights, or wet-to-dry weight ratios in any animals were abnormal. No differences in caecal bacterial concentrations were seen.

Erickson E. J., Saffle J. R, Morris S. E. et al. (1990) Cytomegalo- virus infection promotes bacterial translocation in thermally injured mice. 1. Bum Care Rdabil. 11, (S), 428-435.

LABORATORY STUDIES

Wet disc assay of antimicrobial solutions The wet disc assay method was used to assess the efficacy of a mixture of bacitracin, neomycin, polymyxin (BNP), mafenide hydrochloride (2.5 and 4.0 per cent solutions) and chlorhexidine gluconate against burn wound isolates.

The active antimicrobial activity of BNP was due to neomycin. The activity of 2.5 per cent mafenide hydrochloride was equal to that of a 4 per cent solution of the same compound, the lower concentration could be used clinically with significant savings and perhaps fewer side-effects. Chlorhexidine gluconate (0.05 per cent) was much more active when dissolved in water compared with a saline solution.

Holder I. A. (1990) Wet disc testing of mafenide hydrochloride, chlorhexidine gluconate and triple antibiotic solution against bacteria isolated from bum wounds. 1. Bum Care Rehabil. II, (4, 301-304.

Mupirocin treatment of MRSA The susceptibility of 68 Gram-positive bum wound isolates was tested against topical mupirocin (Bactroban), mafenide acetate, silver sulphadiazine (AgSD) and a mixture of badtracin, neomycin and polymyxin (BNP) using the agar well diffusion method. Mupirocin was found to be a more effective treatment than the other compounds. Of the 68 isolates that were susceptible to mupirocin, 51 were predominantly methicillin-resistant staphy- lococci (MRSA). Mupirocin, AgSD and mafenide acetate were also highly active against Gram-negative organisms.

Thirteen patients with MRSA were effectively treated with mupirocin.

Strock L. L., Lee M. M., Rutan R. L. et al. (1990) Topical bactroban (mupirocin): efficacy in treating bum wounds infected with methicillin resistant staphylococci. 1. Bum Care Rehabil. 11, (S), 454-459.