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It is postulated that toxic substances (burn toxin) synthesized in burned skin are transferred into general circulation and cause multiple organ failure. We found a highly cytotoxic substance, leukotoxin, a linoleate epoxide, exists in burned skin. Leukotoxin, as the name indicates, was synthesized by leukocytes from linoleate as a substrate. The aim of this study is to evaluate the possibility of leukotoxin as a burn toxin. We studied plasma leukotoxin level of four patients with extensive burns (over 50% of body surface area) and examined coagulation studies in these patients. We detected considerable amounts of leukotoxin (11.4 nmol/ml-37.0 nmol/ml) in all patients. Leukotoxin was not detected in the control subjects. Pulmonary edema, cardiac failure, and coagulation abnormalities were found in these patients. Exogeneously administered leukotoxin induced similar pathological conditions in experimental animals to those observed in patients with extensive burns. Hence, it is concluded that leukotoxin is a responsible substance as a burn toxin.

The concentrations of tobramycin (TOB) or cefmenoxime (CMX) in serum and burn blister fluid of 51 burn patients (21 for TOB, 30 for CMX) after an i.v. or i.m. injection were determined to find the optimal administration of TOB (2 mg/kg) or CMX (50 mg/kg). Among the various protocols tested, we found from the values of tAUC for TOB that a bolus i.v. injection, or 1-h drip infusion, or i.m. injection are recommended for systemic sepsis, however, the 1-h drip infusion is strongly suggested for treating wound surface infection. It has also been found that with CMX a bolus i.v. injection with a long period of efficacy is recommended for treating systemic sepsis, while a 1-h drip infusion or bolus i.v. injection was the best method for treating wound-surface infection.

Toxic activity in the extracts of burned human skins impairing respiratory control of rat-liver mitochondria was compared in terms of the severity of burn injury and period after burn. The toxic activity was detected in the extracts from skins of third-degree burn, but not in those from skins of deep-dermal burn or of burn ulcers, in the present experimental conditions. In the case of third-degree burn, the toxic activity was not evident during the first few days post burn, but was significantly increased after 10 days. The results of this study suggest the effective period for early therapeutic débridement of the necrotized tissues in the management of severely burned patients.

Acidic lipids were isolated from human burn blister fluid and the presence of prostaglandins E and F compounds was demonstrated by the thin-layer chromatography. Prostaglandins E1, E2 and F2alpha were identified and quantitatively determined by radioimmunoassay and by gas-liquid chromatography/mass spectrometry. Analyses on burn blister fluid obtained from 35 patients with skin burn indicated an extensive release of prostaglandins into the blister after burn injury in a few hours. The high levels of prostaglandins in burn blister fluid decreased gradually during 24 hours after burn.

Three kinds of 0.2 per cent tobramycin ointment were prepared with tobramycin and 3 ointment bases (cream, polyethylene glycol and hydrophilic petrolatum), and applied to the various wound surfaces of 5 burned patients. The systemic absorptions of tobramycin were compared with the values of the tentative AUC (area under the curve of tobramycin blood level, micrograms.h/ml.g) until 12 hours after the applications, by determining tobramycin level in blood. Similar values of AUC from the cream and polyethylene glycol ointments were obtained, while that of hydrophilic petrolatum ointment was very low. The systemic absorption of tobramycin from the polyethylene glycol ointment was studied when the ointment was applied to the wound surfaces of 7 patients with partial-thickness burn, 9 patients with full-thickness burn and 6 patients with burn ulcer. The mean values of the tentative AUC of patients with partial-thickness burn, full-thickness burn and burn ulcer were found to be 0.06, 0.03 and 0.15, respectively. These results showed that cream and polyethylene glycol bases should be used carefully as a vehicle of tobramycin ointments because of the rapid systemic absorption of tobramycin from human burn wounds, especially burn ulcer.

Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis of pepsin-solubilized collagens from post-burn granulation tissues revealed that type V collagen consisted of 3 alpha chains: alpha 1(V), alpha 2(V), and alpha 3(V). The mean value (0.12 +/- 0.01 SD) of the type V/type I ratio in the granulation tissues was significantly higher (p less than 0.001) than that (0.03 +/- 0.01 SD) of the ratio in normal skin. The average ratio of alpha 1(V):alpha 2(V):alpha 3(V) of type V collagen purified from the granulation tissues was determined to be about 5:3:1. SDS-polyacrylamide gel electrophoresis patterns of 3 alpha chains were not affected in the presence or absence of 2-mercaptoethanol. Purified type V collagen was degraded by bacterial collagenase, but remained intact after tadpole collagenase digestion, in contrast to type I and type III collagens. Amino acid analyses of each alpha chain separated on SDS-gel electrophoresis of type V collagen revealed that all 3 alpha chains of type V collagen were poor in alanine, rich in hydroxylysine, and had high ratios of hydroxylysine/lysine, which are typical features of type V collagen. The purified type V collagen was further fractionated by ammonium sulfate into 2 molecular species, [alpha 1(V)]2 alpha 2(V) and alpha 1(V)alpha 2(V)alpha 3(V). Our data demonstrate that type V collagen in preparations from human post-burn granulation tissues consists of 3 alpha chains and can be resolved into 2 distinct heterotrimers.

Latamoxef (LMOX) (50 mg/kg) was administrated intravenously to burned patients over 1 hour period. Burn blister fluid and serum were taken during 8 hours after injection, and concentrations of LMOX in burn blister fluid and serum were determined by bioassay using E. coli as a test organism. The serum concentrations of LMOX were 170.8 +/- 30.6 micrograms/ml at 30 minutes, 227.0 +/- 19.8 micrograms/ml at 1 hour, 90.3 +/- 21.4 micrograms/ml at 2 hours, 52.9 +/- 14.6 micrograms/ml at 3 hours, 38.7 +/- 13.3 micrograms/ml at 4 hours, 25.1 +/- 8.1 micrograms/ml at 5 hours, 20.5 +/- 8.1 micrograms/ml at 6 hours, 13.0 +/- 5.5 micrograms/ml (mean +/- S.D., n = 5) at 8 hours after the injection. The LMOX concentrations in burn blister fluid were 36.9 +/- 32.8 micrograms/ml at 30 minutes, 77.5 +/- 42.2 micrograms/ml at 1 hour, 85.4 +/- 19.6 micrograms/ml at 2 hours, 76.4 +/- 18.5 micrograms/ml at 3 hours, 63.5 +/- 17.8 micrograms/ml at 4 hours, 54.9 +/- 17.1 micrograms/ml at 5 hours, 34.8 +/- 10.3 micrograms/ml at 6 hours, 25.2 +/- 4.8 micrograms/ml (mean +/- S.D., n = 7) at 8 hours after the injection. The data obtained were analysed pharmacokinetically. The serum levels were analysed by two-compartment model, and the LMOX levels in burn blister fluid were analysed by the model, in which blister was considered as a small part of the peripheral compartment. In results, Tmax and Cmax of LMOX levels in burn blister fluid were calculated as 1.81 hours and 90.6 micrograms/ml, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Transfer of sulbactam/cefoperazone (SBT/CPZ) into the burn blister fluid was studied in 10 burn patients after one shot intravenous injection of 50 mg/kg SBT/CPZ (CPZ 25 mg/kg, SBT 25 mg/kg). CPZ and SBT concentrations in serum and burn blister fluid were determined using bioassay and high performance liquid chromatography (HPLC). The concentration of CPZ in serum reached 109.5 +/- 9.2 micrograms/ml (mean +/- S.E.) at 0.25 hour after injection, and decreased to 6.8 +/- 2.3 micrograms/ml after 8 hours. The concentration of CPZ in burn blister fluid peaked at 4 hours and reached 28.2 +/- 8.0 micrograms/ml. The concentration of SBT in serum reached 75.7 +/- 8.3 micrograms/ml at 0.25 hour after injection, and decreased to 2.3 +/- 0.7 micrograms/ml after 8 hours. The peak concentration of SBT in burn blister fluid was 13.5 +/- 1.8 micrograms/ml at 3 hours. The data obtained were analysed pharmacokinetically. Cmax of CPZ and SBT levels in burn blister fluid were calculated to be 30.4 micrograms/ml and 13.6 micrograms/ml, respectively. The AUC0-8 hrs. (area under the burn blister fluid concentration of drug-time curve between 0 and 8 hours after injection), absorption rate constant (ka) and therapeutic AUC (AUC where drug concentrations were above minimum effective concentration) of CPZ were calculated to be 194.0 micrograms.hr/ml, 1.52 hr-1 and 97.1 micrograms.hr/ml (0.3-11.1 hours), respectively. The AUC0-8 hrs. and ka of SBT were also calculated as 68.3 micrograms.hr/ml and 0.62 hr-1, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of X-prolyl dipeptidyl-aminopeptidase (EC 3.4.14.1) and amine oxidase (EC 1.4.3.6) in serum were assayed in two groups of patients, children two to nine years old and adults 23 to 60 years old, with hypertrophic scars after severe burn. The peptidase activity tended to be low initially for several months after the burn, but then returned to normal after six months. These changes were marked in the child group, less so in the adult group. Similar but less-pronounced changes were also observed in serum amino oxidase activity. The two serum enzyme activities showed a significant positive correlation (r = 0.668, p less than 0.001, n = 27) in the patients.

The penetration of tobramycin ointment (0.2 per cent) through human burn wounds was studied in two patients with superficial dermal burn (SDB) and deep dermal burn (DDB), two patients with DDB, one patient with full thickness burn (FB) and one patient with burn ulcer (BU). After application of the ointment, the absorption of tobramycin occurred promptly with a peak level at 2-6 h in the sera of patients with SDB + DDB and DDB only. In the BU patient it was found at 2 h; while in the FB, at 10-12 h. The excretion of tobramycin into the urine was also studied. The absorption rate constants (ka) of the two SDB + DDB patients were 0.31 and 0.74, of the two DDB patients, 0.079 and 0.18, and those of the DB and the BU patients, 0.053 and 0.95, respectively. The absorption ratios of tobramycin (amount excreted into the urine during 24 h/applied dose) were different, depending on the condition of the burn wound, and ranged from a low of 10.3 per cent (FB) to a high of 44.0 per cent (BU). These results show that the treatment of burn patients with tobramycin ointment to control burn wound infection should be carefully supervised, especially in the case of BU.

Thin split-skin autografts of normal color were performed on depigmented skin caused by second- and third-degree burns in 32 patients. Repigmentation appeared in almost all the recipient areas soon after grafting and no depigmentation occurred again in the treated area.

Pepsin digests of human post-burn wound tissues grafted with autologous fresh skin showed a significantly lower ratio, 0.37 +/- 0.04 (mean +/- S.D.), of type III to type I collagen determined by interrupted gel electrophoresis than the ratio, 0.55 +/- 0.13, measured in ungrafted wound tissues (p less than 0.001). In wounds grafted with frozen skin there was no significant difference from ungrafted wounds, but a significantly higher ratio, 0.46 +/- 0.08, than that in wounds grafted with fresh skin (p less than 0.001). These results were consistent with the histological features of the wound tissues.

Lipid peroxide levels and activities of various enzymes were examined in sera from five thermally injured patients. In all patients examined, serum lipid peroxide levels were increased in the early post-burn period, and thereafter activities of glutamate oxalacetate transaminase, glutamate pyruvate transaminase, alkaline phosphatase and lactate dehydrogenase in the sera became elevated in most patients. From these observations, it is considered that increased lipid peroxides in the bloodstream during the early post-burn period would cause damage to various organs, permitting the leakage of the enzymes into the blood. These results support the view that lipid peroxide may be regarded as a 'burn toxin'.

Transfer of cefmenoxime (CMX) into the burn blister fluids was studied in 10 burned patients with 2 administrated doses (25, 50 mg/kg). CMX concentrations in serum and burn blister fluid after 1 hour intravenous drip infusion were measured using Proteus mirabilis ATCC 21100 as the test organism grown in the DST agar medium. In the case of CMX 25 mg/kg dose, the peak serum concentration was observed 61.5 micrograms/ml at 1 hour, while the peak burn blister fluid concentration was observed 15.2 micrograms/ml at 2 hours. Pharmacokinetic parameters of serum concentration calculated were 1.02 hours as half-life (beta) and 0.42 L/kg as distribution volume, respectively. In the case of CMX 50 mg/kg dose, the peak serum concentration was observed 122.0 micrograms/ml at 1 hour and the peak burn blister fluid concentration was observed 40.8 micrograms/ml at 2 hours. Pharmacokinetic parameters of serum concentration calculated were 1.27 hours as half-life (beta) and 0.55 L/kg as distribution volume. From this study, the dose dependency between 25 mg/kg dose and 50 mg/kg dose in serum and in burn blister fluid is recognized.

Neutral-salt soluble collagen was relatively abundant in young post-burn hypertrophic scars. The content of insoluble collagen was fairly low in granulation tissues, whereas it gradually increased over 2 years and reached a significantly higher value than that in normal skins. Interrupted gel electrophoresis was carried out to estimate the relative proportions of type III and type I collagens in the pepsin digests of human normal skins and post-burn scars. Granulation tissues showed an abnormally higher ratio of type III to type I (0.37--0.72) than the mean value of normal skins (0.17 +/- 0.04 (S.D.)). The ratio gradually decreased to the normal range after 2 years or so.

Fosfomycin (FOM) (50 mg/kg) was administered to burned patients by intravenous bolus injection. Burn blister fluid and serum were taken during 8 hours after injection, and concentrations of FOM in burn blister fluid and serum were determined by bioassay using Proteus sp. (MB-838) as the test organism. The serum concentrations of FOM were 257 +/- 34.6 micrograms/ml at 15 minutes, 222 +/- 34.8 micrograms/ml at 30 minutes, 166 +/- 34.6 micrograms/ml at 1 hour, 114 +/- 43.9 micrograms/ml at 2 hours, 79.5 +/- 34.9 micrograms/ml at 3 hours, 63 +/- 36.4 micrograms/ml at 4 hours, 44.3 +/- 27.6 micrograms/ml at 5 hours, 29.6 +/- 20.9 micrograms/ml at 6 hours and 17.9 +/- 12.8 micrograms/ml at 8 hours after the injection. FOM concentrations in burn blister fluid were 64.4 +/- 18.1 micrograms/ml at 30 minutes, 77 +/- 26.0 micrograms/ml at 1 hour, 71.6 +/- 24.7 micrograms/ml at 2 hours, 64.8 +/- 23.6 micrograms/ml at 3 hours, 43.2 +/- 8.8 micrograms/ml at 4 hours, 24.8 +/- 7.9 micrograms/ml at 6 hours and 17.9 +/- 10.5 micrograms/ml at 8 hours after the injection. The obtained data were analysed pharmacokinetically. The serum levels were analysed by a two-compartment model, and the transfer of FOM into burn blister was analysed by a modified deconvolution method. In results, Tmax and Cmax of FOM levels in burn blister fluid were calculated as 1.3 hours and 80.9 micrograms/ml, respectively. The transfer rate constant of FOM from serum to burn blister fluid (K1) and that from burn blister fluid to serum (K2) were calculated as 0.612 hr-1 and 1.10 hr-1, respectively.