It is well known that in patients with severe burn, especially when complicated by sepsis, the breakdown of body proteins is acceleraled, producing a hypercalabolic response. Negative nitrogen balance and malnutrition will develop rapidly, predisposing to various complications. High calori intake and enhancement of anabolic process might fail to improve the patient′s nutritional condition. A skeletal muscles account for over 50% of body cell dry weight, their catabolism exerts profound effect on whole body metabolism. By using modern molecular biology techniques, one of the mechanisms underlying skeletal muscle proteolysis is shown to be activation of the ubiquitin proteasome pathway. The role of its possible modulating factors in inducing muscle protein breakdown after burn injury was explored in rat models of burn injury with or without sepsis. Muscle spesimens obtained from severely burned patient with sepsis was also collected for study.The results were as follows. (1)The total and myofibrillar proteolytic rate in extensor digitorum longus (EDL) muscle was increased markedly, especially the expressions of ubiquitin, and mRNA of subunit RC2(the largest subunit of 20s proteasome) were prominantly increased in EDL muscle. There was a significant positive correlation between the proteolytic rate and the expression of mRNA of ubiquitin, or mRNA of subunit RC2, after the stimulation of burn injury. On the other hand, there was no significant change in proteolytic rate and transcription of ubiquitin in soleus (SOL) muscle. (2)The myofibrillar proteolytic rate and the ubiquitin proteasome component were significantly enhanced in rats with sepsis compared with control group. There were significant positive correlations among plasma concentration of endotoxin, TNF ?, cortisol and respective values of myofibrillar proteolytic rate, and ubiquitin proteasome component. (3)There were significant positive correlations between the urinary output of 3 methylhistidine (3 MH)in 24h urine and respective values of plasma concentration of cortisol, TNF ?, and endotoxin in severely burned patients with sepsis. The expressions of ubiquitin mRNA 2 4 kilobase pair (?B), 1.2kb, C 2 subunit mRNA and the protein expressions of ubiquitin in quadriceps femoris muscle were significantly increased compared with the control group. (4)Muscle proteolytic rate was markedly enhanced when myotube was cultured with TNF ?. However, by using the ubiquitin proteasome inhibitor mG132, significant decrease in the muscle proteolyitc rate was observed. (5)Glucocorticoid could increase the skeletal muscle proteolytic rate, especially the myofibrillar proteolytic rate, through activating the ubiquitin proteasome system at gene level. However, this effect could be greatly bluned by glucocorticoid receptor antagonist RU38486. (6)NF ?B activity in skeletal muscle of burned rat with sepsis was markedly increased. However, by using inhibitor of NF ?B, the NF ?B activity was down regwlated in the muscle, and a decrease in the total and myofibrillar proteolytic rate was observed. (7)Decrease in transcriptional expression of ubiquitin and reduction in the skeletal muscle proteolytic rate were found when escharectomy was performed during early stage of burn injury. The results suggested that the treatment strategies for prevention of skeletal muscle proteolysis of postburn sepsis should firstly be aimed at eradication of devitalized tissues, i.e. prevention of sepsis by reonoval of the primary injury. Secondly, attention should be paid to modulating or controlling the process of ubiquitin proteasome pathway in response to burn injury, and this might provide an effective way to reduce skeletal muscle protein wasting by specifically inhibiting the specific enzymes or subunits involved in the enhancement of the activity of ubiquitin proteasome pathway after burn injury. However, more studies in the ubiquitin proteasome proteolytic pathway in severe burn injury are necessary to confirm this assertion.

The present article summarized briefly the experiences and lessons learned in the management of mass burn casualties,and also gave a brief account of the present status of the system of emergency care of mass casualties in our country.The authors proposed herewith an organizational system conforming to the status quo of our country.It was suggested that through learning from attending seminars and training in specialty centers,devotion to intensive research of relevant problems and constant interchange of experiences and ideas,the ability of professional staff to meet the needs of urgent and heavy duty could be raised in salvaging mass casualties both in peace time and war.

Objective To investigate the relationship between antibiotic administration and the changes in constituent ratios of preponderant pathogens in infection of burn wounds in our burn unit. Methods The consumption of different kinds of antibiotics [expressed as the number of defined daily doses (DDD)/100 patient-day], as well as the constituent ratio of Staphylococcus aureus and Pseudomonas aeruginosa, and percentage of methicillin-resistant S. aureus (MRSA) among all positive cultures of S. aureus were calculated from 1995 to 2004, and their correlation was analyzed. Results Within this period, it was found that the consumption of first and second-generation cephalosporins and aminoglycosides, including cefazolin and amikacin, was decreased remarkably, while the consumption of antibiotics combined with lactamase inhibitor, third-generation cephalosporins, quinolones, including ceftazidime, levofloxacin and fosfomycin, was increased significantly. At the same time, the constituent ratio of P. aeruginosa declined to certain extent, while the constituent ratio of S. aureus gradually rase, but no increase was found in percentage of MRSA in S. aureus. The constituent ratios of S. aureus and P. aeruginosa were correlated to consumption of more than ten kinds of antibiotics or antimicrobial agents. Conclusions The results suggested that more cefazolin or amikacin and less antibiotics with lactamase inhibitor or third generation cephalosporins were used in the treatment of burn infection might help decrease the infection caused by S. aureus, and that when more carbopenem or cefoperazone/sulbactam were used there might be a tendency of declination of P. aeruginosa infection.

Objective To investigate whether intestinal bacterial translocation in scalded rat with delayed fluid resuscitation (DFR) was partly due to the reduction of the expression of rat defensin (RD), which was the most important defensin in rat intestinal defensin family excreted by Paneth cells. Methods Fifty-six SPF rats were randomized to 3 groups: sham injury group (n=8); early resuscitation (ER) group (n=24), receiving fluid resuscitation immediately after scald (30% TBSA, third degree); delayed resuscitation group (n=24), receiving fluid resuscitation 6 hours after scald. The animals (n=6, at each time point) were sacrificed at 8, 24, 72 hours after injury. The expression of RD-5 in the terminal ileum was determined with PCR technic. Morphological changes in ileal Paneth cells were observed. Quantitative bacterial cultures of mesenteric lymph nodes (MLN), liver, spleen and lung were also done. Results In both ER group and DR group, ileal RD-5 mRNA expression level was significantly increased at 8 hours after injury, and it began to decrease at 24 hours until the end of the experiment, when the level was much lower than that of the sham group. When two experimental groups were compared, RD-5 mRNA expression level was significantly higher at 8 hours and significantly lower at 72 hours in DR group than in ER group. There were no obvious morphological changes in ileal Paneth cells in all 3 groups. Although high incidence of bacterial translocation was observed in both experimental groups, it was significantly higher in DR group than in ER group. Conclusions DFR did not cause Panth cell damage, and RD-5 changes did not contribute to bacterial translocation in 24 hours after DFR, as the increase in RD-5 mRNA might be an innate protective reaction. However, the decrease in RD-5 production at 72 hours may play a role in bacterial transloca- tion.

Objective To investigate the etiological and epidemiological factors of critical and severe burn injuries,in tending to provide a theoretical basis for the prevention of critical and severe burn injury.Methods The clinical data of a total of 1 043 patients with critical and severe burn injury hospitalized from 1982 to 2006 were retrospectively analyzed,and the sex ratio,age distribution,etiological factors,injury sites,seazonal distribution,duration before hospitalization,complications and fatality of these patients were statistically analyzed.Results From 1982 to 2006,the number of burn patients admitted to our hospital presented an increasing trend,and the number of critical and severe burn patients increased obviously.The sex ratio(male/female) was 3.3∶1,and it obviously declined during the last 5 years.The proportion of infant and childhood patients presented a significantly increasing trend,occupying 41.2% of critical and severe burn patients in the last 5 years.Summer was the predominating season for occurrence of burn injury(40.3%),followed by spring(23.5%),autumn(22.4%) and winter(13.8%).54.8% of burn injury occurred in daily life,the remaining 45.2% of patients got burn injury in work,but the former reached 63.3% in the last 5 years.Heat was the main etiological factor,occupying 85.5%,of which flame was the most important cause,and hot fluid scald was increasing in recent years.Only 51.2% of the patients went to visit doctor within 6h after injury.21.0% of the patients were complicated with inhalation injury,and 17.7% was in shock when they came to the hospital.The fatality rate of critical and severe burns was reduced from 16.3 %(1982-1986) to 4.2%(2002-2006).Conclusions It is urgent to prevent critical and severe burns,especially in the youth and childhood.Information regarding prevention,self-aid and self-protection in fire accident should be actively spread among both the workers in industrial and mining enterprises and community inhabitants.The methods easy to use for shock prevention before hospitalization should be explored as early as possible.

To observe the changes in proteolytic rate of different kinds of skeletal muscle and the content of serum glucocorticoid in rats after burn injury,to compare the response of different types of skeletal muscle to burn injury,and to preliminarily investigate the factors modulating skeletal muscle proteolysis after burn injury, Wistar rats were inflicted 30%TBSA(total body surface area) full-thickness burn. The rats were randomly divided into 4 groups as the following: 2h, 6h, 12h and 24h after burn injury, each time point was matched with a sham control group. In-vitro muscle incubation system with sufficient oxygen supply as well as amino acid automatic analyzer were used for the assessment of the proteolytic rate of extensor digitorium longus(EDL) and soleus(SOL)muscles. The level of serum glucocorticoid was determined with radio-immuno assay. The result indicated that total proteolytic rate and myofibrillar proteolytic rate in EDL muscle increased strikingly at each time point after burn injury, and the rise of myofibrillar proteolytic rate was even greater in magnitude. No statistically significant difference in total and myofibrillar proteolytic rate occurred in SOL muscle during postburn period. Serum glucocorticoid notably increased in each observation time point compared with that of normal control( P

To study the regularity of ubiquitin and ubiquitinated protein expression in rat skeletal muscle after burn injury, the molecular mechanism of skeletal muscle protein catabolism was investigated. Wistar rats were inflicted on a 30% full thickness burn. They were grouped according to the time of sacrifice :2, 6, 12 and 24 hours after burn, each group included normal control. The extensor digitorium logus (EDL) muscle was taken to assay the proteolytic rate and the expression of ubiquitin and ubiquitinated protein during postburn period. It was found that proteolytic rate of EDL muscle was markedly enhanced, especially in myofibrillar proteolytic rate, by 185% and 153% at 12h and 24h after burn injury, respectively. The contents of free ubiquitin and ubiquitinated protein in rat EDL muscle were significantly increased after burn injury, especially at 12 and 24 hour. The contents of free ubiquitin and ubiquitinated protein increased 33% and 186% at 12h postburn, increased 30% and 163% at 24h,respectively. The high protein catabolism of skeletal muscle during postburn stage is in close relation to high expression of free ubiquitin and ubiquitinated protein.

To study the effects of TNF ? on the protein metabolism and the ubiquitin system gene expression in isolated skeletal muscles, after dissecting and isolating the extensor digitorium longus (EDL) muscles, the in vitro oxygen rich muscle incubation system and as high performance liquid chromatography were used to assess proteolytic rate of the samples. The EDL muscles in study group were incubated with media containing 6 000 U/ml recombinant rat TNF ?. In control group, the media were of the same composition as that of the study group except recombinant rat TNF ?. The expressions of ubiquitin mRNA and C 2 mRNA in rat EDL muscles were determined by Northern blot analysis. No notable difference was observed in the total and myofibrillar proteolytic rate in EDL muscles between the two groups. The expressions of ubiquitin mRNA(2 4kb) and C2 mRNA of EDL muscle incubated with medium containing TNF ? were increased by 151% and 56%, respectively, as compared with those in control group. TNF ? could directly strengthen the function of ubiquitin dependent proteolytic system, but further studies are necessay to elucidate whether TNF ? could directly increase the proteolytic rate in skeletal muscle.

Burns ; complications ; diagnosis ; prevention & control ; Humans ; Sepsis ; diagnosis ; etiology ; prevention & control

Objective To study the effects of tumor necrosis factord (TNF ?)on degradation of long lived protein in cultured myotubes, myoblasts were proliferated in tissue block culture and fused into myotubes. Methods Then the protein in myotubes was radiolabelled with L [3,5 3 H] tyrosine. Myotubes were either cultured with TNF ? 2000U/mL or without TNF ?, and 12h, 24h, 36h, 48h later, the amounts of L [3,5 3 H] tyrosine in culture medium and cells were determined, and the degradation rates of long lived protein were calculated. Other myotubes were cultured either with 50?mol/mL proteasome inhibitor MG132 or 50?mol/mL MG132 and TNF ? 2000U/mL, and long lived proteolytic rates were calculated by the same method after 24h culture. Results The long lived proteolytic rates in myotubes cultured with TNF ? were increased significantly at all time points compared with control group ( P