Annals of the M.B.C. - vol. 1° - n° 2 - September 1988

INTERNATIONAL ABSTRACTS

STUDIES ON SYSTEMIC ABSORPTION OF TOBRAMYCIN IN POLYETHYLENE GLYCOL OINTMENT APPLIED TO WOUNDS OF BURN PATIENTS

A study was made of the penetration of tobramycin ointment (0.2 per cent) through human burn wounds in 6 patients. Two had superficial dermal bums (SDB) and deep dermal burns (DDB), two DDB only, one had full thickness bums (FB) and one a bum ulcer (BU). When the ointment was applied, tobramycin absorption was rapid, peaking at 2-6 h, in the sera of patients with SDB + DDB and DDB only. In the BU patient the peak was at 2 h, and in the F13 patient at 10-12 h. A study was also made of tobramycin excretion into the urine. The absorption rate constants were calculated. The values were 0.31 and 0.74 in the two SDB + DDB patients, 0.079 and 0. 18 in the two DDB patients, and 0.053 and 0.95 in the DB and BU patients. The condition of the bum wound influenced the different absorption rations of tobramycin (amount excreted into the urine during 24 h/ applied dose), which varied from 10.3 per cent (FB) to 44.0 per cent (BU). This study shows that to control burn wound infection particular care should be taken in treating burn patients with tobramycin ointment, especially in the case of burn ulcer.

Aoyarna H., lzawa Y., Nishizaki A., Sunada H., Okuda J. Bums, 12: 153-160, 1986.

Certain preclinical assessment procedures are required for wound dressings. The parameters which must be considered are tensile mechanical properties, conformability to body surfaces, water-vapour transmission and gas permeability. Dressing conformability is assessed by a new test which has been specifically developed, and established techniques were used to assess the other parameters. The procedures help clinicians by providing a screen reducing the number proceeding to full expensive clinical trials. They also help manufacturers trying to optimize the characteristics of dressings and assess the suitability of other materials that might be used.

Queen D., Evans J.H., Gaylor J.D.S., Courtney J.M., Reid W.H. Bums, 12: 161-166, 1986.

EFFECTS OF THERMAL TRAUMA ON CARDIAC FORCE OF CONTRACTION

Previous studies have shown that thermal trauma-induced depression of cardiac output can be significantly increased by using potent peripheral vasodilating drugs. This means that an increase in peripheral resistance and a decrease in venous return, rather than a direct depression of myocardial contractile force, are the probable causes of most of the depression in cardiac output after thermal trauma. Studies were made using a strain gauge arch sewn on the left ventricle in a mongrel dog to measure myocardial force of contraction. The dog was anaesthetized with sodium pentobarbital and received a 15 per cent total body surface area full skin thickness flame bum. The results of this study indicated a significant decrease in cardiac output immediately post-burn, which lasted for 7 h. After the bum there was an immediate reduction in myocardial force of contraction, measured in grams, followed by a return to pre-burn values within 3 h post-bum. Verapamil, a calcium-channel-blocking substance, was given to one series of animals. After administration of the drug the animals' cardiac output returned to pre-bum levels, but during the experiment myocardial force of contraction stayed significantly lower than pre-bum values. Correlation coefficients comparing cardiac output and myocardial force of contraction did not indicate any significant relationship between values in either treated or untreated animals.

Hilton J.G., Marullo D.S. Burns, 12: 167-171, 1986.

EFFECT OF NON-LETHAL SCALDING ON THE AMOUNT OF DNA AND RNA IN RAT LIVER

DNA and RNA content was measured in rat liver homogenate, supernatant and nuclei after scalding. The highest increases in nuclear DNA and RNA occurred 12 h after burn injury. The quantity of RNA in the rat liver supernatant and homogenate was at maximum levels at 24 h and 48h respectively. The findings show that thermal injury caused activation of the genetic apparatus in rat liver cells, and correspond well with a significant role of the liver in post-bum metabolism.

Magic L, Ristovic B., Pantelic D. Burn 12: 172-175, 1986.
Annals of the M.B.C. - vol, 1 - n'2 - September 1988

Bum injuries in rats and guinea-pigs cause a variation in the interaction between blood platelets and the walls of blood vessels. Burned experimental animals were treated with heparin, nicotinic acid, thrental, phytin, glutamic acid and alphatocopherol. There was a reduction of the increase in platelet-vascular wall interaction, an improvement of the microcirculation in mesenteric vessels and an increase of the animals' toleration to physical stress.

Baluda V.P., Lukhoyanova T.I., Kozelskaya L.V., Zyablitsky V.M., lashvili B.P., Vakulenko A.D., Staroselskaya A.N.
Burns, 12: 176-183, 1986.

THE EFFECTS OF ADMINISTRATION OF DRUGS INFLUENCING HAEMOSTASIS DURING TREATMENT OF PATIENTS WITH BURNS

When drugs influencing disordered haemostasis (heparin, nicotinic acid, thrental, phytin and alphatocopherol) were administered to bum patients, the period of treatment was reduced by 43 per cent. Necrotic eschar separation occurred 7-9 days earlier and the time required to prepare bum wounds for surgical yepair was reduced by 5 days.
There was a higher percentage of attachment of the grafts. Only 35 per cent of patients treated with the drugs were found to have necrotic changes of the gastrointestinal tract, compared with 60 per cent of patients treated in the usual way.

lashvili B.P., Baluda V.P., Lukhoyanova T.I., Kozelskaya L.V., Katsitadze N.G., Karnkarnidze M.V., Robakidze T.A.
Burns, 12. 184-187, 1986.

CELLULAR IMMUNE MECHANISM IN THERMALLY INJURED MICE

A study was made to attempt to establish an animal model in order to analyse the cellular immune alterations caused by thermal injury and to compare the results with those obtained in human patients. C57 black mice (b I) were subjected to a standard bum in 20 per cent of the body surface area. The results showed that there was a loss of total T cells until post-burn day 10 and an increase in B cells on postbum day I only. There was a high lymphocyte proliferative response to PHA, and null cells appeared on post-bum day 10. A significant generalized depression in the immune responses was observed until post-bum day 10. The results were not however comparable with the human studies.

Mistry S., Mistry N.F., Antia N.H., Arora S. Bums, 12: 188-192, 1986.

CRYOPRESERVATION OF SKIN: AN ASSESSMENT OF CURRENT CLINICAL APPLICABILITY

A survey is made of the literature since 1966 dealing with techniques for the cryopreservation of human cadaver skin for allografting, and the measurements governing the freezing process are identified and discussed. The optimal viability of frozen-thawed skin has been obtained by means of controlled cooling at 1-5 'C per minute combined with thawing at 50-70 'C per minute in the presence of glycerol or dimethylsulphoxide in a concentration of at least 10 per cent. The importance of various thermal and chemical values are discussed, together with their control. The basic physiochemical and permeability properties of skin at sub- and supra-freezing temperatures have been little studied to date. When more data are available, they will be of fundamental importance in the rational design of optimal freezing procedures.

Aggarwal S.J., Baxter C.H., Diller K.A. J. Bums Care Rehab., 6: 469-476, 1985.

Chronically instrumented sheep were insufflated with smoke from burning cotton cloth, procuring inhalation injury. Over a 72-hour period the animals showed a sharp increase in lung lymph flow and lung water, together with electron micrographic evidence of interstitial oedema. The lumph flow changes were associated with an increase in the lymph-to-plasma protein concentration ratio, which is probably due to an increase in pulmonary microvascular permeability to protein. The light micrographic presence of neutrophils in the lung microvasculature and increased lysosomal enzyme beta-glucuronidase in the lymph suggest that this change in permeability was caused by products of these cells. The pulmonary capillary endothelial cell marker, converting enzyme, was elevated in the blood, whereas in electron micrographs these cells appeared normal. Fluid changes were associated with a fall in total thoracic compliance. It is thus clear that smoke inhalation produces neutrophilrelated pulmonary oedema. The exact site of the injury is unknown, but oedema formation is responsible at least in part for the impairment of respiration, as indicated by the reduced compliance.

Traber D.L., Schlag G., Real H., Traber L.D. J. Bum Care Rehab., 6: 490-494, 1985.

A SUCCESSFUL BURN PREVENTION PROGRAMME IN ELEMENTARY SCHOOLS

Eckelt K., Fannon M., Blades B., Munster A.M. J. Burn Care Rehab., 6: 509-510, 1985.

USE OF THIRD-GENERATION CEPHALOSPORINS IN SEPTICAEMIC BURNED PATIENTS

The results of an open study showed that thirdgeneration cephalosporins were effective in the treatment of patients with severe underlying diseases and bums who had infections due to aerobic, multiresistant, gram-negative bacilli. They were particularly effective with regard to cases of severe Pseudonomas aeruginosa infections. Ceftazidime was better in vitro activity against P. aeruginosa strains than other cephalosporins tested, i.e. moxalactam, cefotaxime and cefoperazone. The incidence of adverse clinical reactions was low, but the incidence of colonization or superinfection was noteworthy. These drugs do not appear to have significant renal toxicity and can be given in fairly high doses with few major side-effects.

Menier M., Cran S., Jaspar N., Ley H., Clurneck N., May SK, Dogo G. (eds)
Care of the burn wound, Int. Congr., Geneva 1983, 7-12 Karger, Basel, 1985.