Abstracts 145

of insensible weight loss using a sensitive hydraulic scale have shown no excessive increase in evaporative water losses at an ambient temperature of 25 “C and a relative humidity of 44 per cent. The patients were able to maintain their water balance ad Iibitum without difficulty or the need for supplemental routes of water administration. Additional benefits of the laminar flow unit were that nutrition was more easily maintained and weight loss was minimal. Also, septic complications were sharply reduced in this series. The laminar flow unit appears to be a safe, effective method of treating patients with burns.

Larkin J. M. and Moylan J. A. (1978) Evaporative water losses in patients treated in a laminar flow burn unit. J. Slug. Res. 24, 65.

ANIMAL STUDIES

Steroids and burn wound bacteria Topical application of steroids has been shown experimentally in rats with full-thickness burns covering 20 per cent of the body surface to prevent dermal ischaemia and maintain capillary perfusion in the ‘zone of stasis’ of the burn wound. This apparent advance would be nullified if such treatment increased susceptibility to bacterial proliferation. In the model studied, susceptibility to bacterial invasion and proliferation was not increased by topical application of methyl prednisolone. Addition of vitamin A to the treatment also had no effect on the numbers of bacteria in the burn wound.

Kucan J. 0. and Robson M. C. (1978) Influence of topical steroids on bacterial proliferation in the burn wound. J. Surg. Res. 24, 79.

Hormone and glucose relationships A porcine experimental burn model showing hormonal and metabolic alterations similar to those reported in human burns is described. In particular, increased glucagon and suppressed insulin secretion are associ- ated with disturbed lipid and carbohydrate regulation. Hyperglucagonaemia is exaggerated after a&nine stimulation. With appropriate fluid resuscitation, correction of hormone-metabolic aberrations is shown, suggesting that this controlled model of thermal injury may be appropriate not only to describe the pathophysiology of the burn state but also to explore alternative r&hods of therapy.

Wachtel T. L., Shuck J. M., Eaton R. P. et al. (1978) Glucagon, insulin and glucose relationships in a porcine experimental burn model. J. Surg. Res. 24,70.

the scalded animals cardiac output decreased by 58 per cent by 75 min post burn. Three different blood flow responses were noted: (a) the brain, heart, hepatic artery and adrenals received an increased fraction of the cardiac output; (b) the fractional distribution to the diaphragm, liver (portal), spleen. gastrointestinal tract, muscle (from burned portion of the body) and bone remained constant; and (c) the pancreas, burned skin, un-burned skin and adipose tissue received a reduced fraction of the cardiac output.

Although some regions of the body (i.e. brain and heart) received a greater percentage of the total cardiac output after burning, the cardiac output decrease was sufficient to cause a depression in absolute blood flow to all but two sites (adrenals and hepatic artery).

Ferguson J. L., Merrill G. F., Miiler H. 1. et al. (1977) Regional blood flow redistribution during early burn shock in the Guinea-pig. Circulatory shack 4, 317.

Resistance to aminoglycoside antibiotics Between July 1974 and June 1976 a number of isolates of Escherichia coli, KlebsieIla pneumoniae and Pseudomonas aeruginosa from patients with burns showed a shift to smaller zone diameters with gentamicin than did isolates from the general hospital population. Although many had zone diameters > 13 mm and would have been considered susceptible by this breakpoint, they were found to have minimal inhibitory concentrations of >8 pg of gentamicin per ml by agar dilution testing. Zone diameters and minimal inhibitory concentrations of gentamicin, tobramycin and amikacin were subsequently com- pared for 168 isolates from both the burn centre and the general hospital. The results indicated that many isolates that fell into presently used gentamicin- and tobramycin-susceptible categories by disc diffusion tests were resistant by minimal inhibitory concentra- tions. The results indicate that the criteria for gentamicin disc diffusion testing should include an intermediate or indeterminate category, and that the limits of the intermediate category for tobramycin and amikacin should be expanded.

Minshew B. H., Pollock H. M., Schoenknecht F. D. et al. (1977) Emergence in a burn centre of populations of bacteria resistant to gentamicin, tobramycin and amikacin: evidence for the need for changes in zone diameter interpretative standards. Anrimicrob. Agenrs Chemother. 12, 688.

Regional blood flows The distribution of blood flow was determined with LABORATORY STUDIES microspheres labelled with either cerium 141, stron- tium 85 or scandium 46 and of 15 urn+ 5 urn in T lymphocytes and thymosin diameter, in anaesthetized Guinea-pigs &ei;ing a Patients with severe thermal burns demonstrate a burn covering approximately 50 per cent of the body decreased cellular immunity. Studies were made to surface (3 s in water at 100 “c). Cardiac output and determine whether thymosin enhances in vitro fractional blood flow measurements were made before T lymphocyte functions in such patients. Peripheral burning, 15 min post burn and 75 min post burn. In blood lymphocytes were obtained serially from 22

146 Burns Vol. ~/NO. 1

burned patients and 35 healthy adults. In vitro lymphocyte functions were evaluated by E rosette formation, lymphocyte culture responses to phytohae- magglutinin, Con A, PWM, PPD, SK-SD, mumps antigen, tetanus toxoid and mixed lymphocyte culture reactions. These tests were performed with and without in vitro addition of thymosin. Most of the measure- ments were decreased significantly in patients during the first 2 weeks after burning. The in vitro addition of thymosin significantly restored impaired lymphocyte responses, except in mixed lymphocyte culture reactions. These results demonstrate that thymosin enhances certain in vitro T lymphocyte functions in burned patients. They further suggest that the administration of thymosin may restore decreased cell mediated immunity in patients with severe burns.

Ishizawa S., Sakai H., Sarles H. E. et al. (1978) Effect of thymosin on T lymphocyte functions in patients with acute thermal burns. J. Trauma 18, 48.

Tobramycin-resistant organisms Tobramycin-resistant burn wound isolates of Klebsiella pneumoniae and Enterobacter cloacae, together with Escherichia coli K12 transconjugants from these two strains, were examined for plasmid deoxyribonucleic acid (DNA). All the resistant strains contained a common high molecular-weight, coval- ently closed, circular DNA plasmid that was absent in the tobramycin-susceptible E. coli recipient strain. The common plasmid residing in E. cloacue was designated pIE098 and that residing in K. pneumoniae was designated pIEO99. Both plasmid species were found to have a molecular mass of approximately 60 x lo8 daltons and a guanine plus cytosine content

of 50 mol per cent. The DNA that was extracted from all of the tobramycin-resistant strains tested was able to hybridize to 86-100 per cent with pIE098 and pIE099 (3H) DNA generated by EcoRI to produce fragments of a size similar to those generated by BamHI. This study illustrates the usefulness of simple screening methods for antibiotic-resistant plasmids in a hospital epidemiological situation.

Elwell L. P.. Inamine J. M. and Minshew B. H. (1978) Common plasmid specifying tobramycin resistance found in two enteric bacteria isolated from burns patients. Antimicrob. Agents Chemother. 13, 312.

SURGICAL TECHNIQUES

Joint contractures An analysis of 625 patients who had sustained burns across the axillae, elbows, wrists or knee joints indicates that the use of splints and pressure across these joints will not only greatly decrease the incidence of contractures but will also reduce the frequency and need for release operations. However, these appliances must be used for at least 6 months (longer if possible) if substantial benefits are to be obtained.

Huang T. T., Blackwell S. J. and Lewis S. R. (1978) Ten years of experience in managing patients with burn contractures of axilla, elbow, wrist and knee joints. Plast. Reconstr. Surg. 61, 70.

Abstracts compiled by J. W. L. Davies, DSc, MRC Industrial Injuries and Burns Unit, Birmingham Accident Hospital, Bath Row, Birmingham,BIS 1NA.

References to articles published between March and June 1978

Anon. (1978) Psychic survival after the burn. Emer- gency Med. 10, 196.

Baar S. (1978) The red cell enzyme response to thermal injury. Burns 4, 207.

Bhatia B., Saxena K. C., Sethi N. et al. (1978) Histopathological and enzymatic changes in Guinea-pigs following experimental burn. Indian J. Exp. Biol. 16, 71.

Bhatnagar S. K., Gupta J. L. and Srivastava J. L. (1978) The role of central venous pressure moni- toring in the management of burn shock. Burns 4, 171.

Bloem J. (1977) Deep burns of hands. Ann. Chir. 31, 1103.

Borras C., Garcia J. A., Sancho V. et al. (1977) Local treatment of burns in children. Rev. Esp. Pediatr. 33, 695.

Chari P. S., Bapna B. C. and Balakrishnan C. (1978) Electrical burns causing a urinary bladder fistula. Plast. Reconstr. Surg. 61,446.

Delaveau P. and Friedrich-Noue P. (1977) Cutaneous absorption and urinary elimination of a sulfadia- z&-silver compound used in burns therapy. Therapie 32, 563.

Demling R. H., Mazess R. B., Witt R. M. et al. (1978) A study of burn wound edema using dichromatic absorptiometry. J. Trauma 18, 124.

Demling R. H., Moylan J. A,, Ellerbe S. et al. (1977) Experience with laminar airflow in the management of maior burns. Wis. Med. J. 76. 5149.

Dhennin C., Pinon G. and Greco J. M. (1978) Alterations of complement system following thermal injury: use in estimation of vital prognosis. J. Trauma 18, 129.