Animals ; Burns ; complications ; Cicatrix ; etiology ; physiopathology ; Fetus ; physiopathology ; Humans ; Wound Healing

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.

Parkland formula is the most widely used resuscitation formula in burn care. However, a growing number of disputes have been raised along with the development of medical technology, among which its total volume and composition of the fluid are the two foci. Firstly, Parkland formula may lead to an untoward phenomenon nicknamed "fluid creep", which may lead to complications such as abdominal compartment syndrome. Secondly, along with the deeper understanding of how permeability of blood vessels changes after burn injury, colloid is recommended to be given after the third 8 h post-burn. Additionally, controversy exists in the choice of different colloid solutions. The safety of different colloid solutions remains to be further elucidated. This article will deal with all of the above-mentioned problems.
Burns ; physiopathology ; therapy ; Fluid Therapy ; methods ; Humans ; Isotonic Solutions ; therapeutic use ; Resuscitation ; methods ; Treatment Outcome

OBJECTIVE To analyze the changes in bacteria constitution in severe burn wounds in different stages so as to provide reference for clinical prevention and treatment.METHODS A total of 36 casualties with severe burn injuries(≥50.0% total burn surface area) and hospitalized within 5 days post-burns from 2004 to 2006 were enrolled in the study.Samples were collected in the burn wounds from the first day to two months post-burns.RESULTS Totally 476 bacterial strains were isolated and Gram-negative bacteria accounted for 64.1%.However,in term of the single bacterial strain,Staphylococcus aureus(SAU) ranked first and the follows were Pseudomonas aeruginosa(PAE) and Acinetobacter baumannii(ABA).During the first week and the six weeks to 2 months post-burns,Gram-positive bacteria were dominant and SAU ranked first.From the second week to the fifth week,Gram-negative bacteria were dominant,PAE and ABA were the main bacteria.Even though Gram-negative bacteria dominated in these periods,SAU still ranked the first or the second in terms of single bacterial strain.CONCLUSIONS Bacteria constitution in burn wounds differs in different stages.It must be stressed to prevent infections of SAU regardless of any stages,as well as ABA infections since the percentage of ABA has increased markedly in recent years.

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.

In recent years, negative pressure wound therapy (NPWT) technique has been widely used in burn surgery, including wound repair, skin grafting, and cosmetic procedures, showing promising clinical results. Based on the literature and clinical experience, the mechanism of NPWT and its clinical application in burn surgery are briefly iterated herewith.
Burns ; surgery ; Humans ; Negative-Pressure Wound Therapy ; Skin ; Skin Transplantation ; Wound Healing

Objective To compare the difference of wound healing quality of composite skin grafting consisting of xenogeneic (porcine) acellular dermal matrix (PADM) combined with micro-autograft or split-thickness autograft of skin. Methods Seventy-two Sprague-Dawley rats with full-thickness skin defect on the back were randomly divided into three groups,namely test group I with PADM with split-thickness autologous skin,test group II with HADM with autologous micro- skin and allogeneic skin graft,and control group with autologous micro-skin with allogeneic skin graft to cover the skin defect area respectively. The take rate and the condition of wound healing,and also the rates of wound contraction were calculated. Tissue samples were harvested for histological examination. Results The wound contraction was less in test group I and II than that in control group( P

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.

Objective To study the effect of testosterone on skeletal muscle atrophy of rats induced by dexamethasone,and to explore the relationship between androgen and ubiquitin ligase expression in skeletal muscle.Methods Forty female SD rats were randomly divided into four group:control group(CON),dexamethasone group(DEX),testosterone group(TES)and testosterone plus dexamethasone group(TES+DEX).Blood samples were collected from the abdominal aorta and then centrifuged.The supernatant was collected and stored at-20℃.Gastrocnemius was removed and stored at-80℃.The cross-sectional area(CSA)of muscle fiber was determined by microscopic images of digitized muscle sections,using a computer-based imaging processing system.The expression of muscle atrophy F-box(MAFbx)and muscle RING finger-1(MuRF1)mRNA in skeletal muscle was determined by real-time PCR.The expression of testosterone protein in serum was determined by immunoradiometry.Results Dexamethasone increased the expression of MAFbx and MuRF1 mRNA in skeletal muscle(P

Objective To study the therapeatic effect of testosterone on skeletal muscle atrophy induced by dexamethasone in rat, and to explore the relationship between androgen and insulin like growth factor 1 (IGF-1) expression in skeletal muscle and serum. Methods Forty female Sprague-Dawley rats were randomly divided into four groups: control group (CON) in which the rats were injected with saline and sesame oil for 10 days; dexamethasone group (DEX) in which the rats were injected with dexamethasone and sesame oil for 10 days; testosterone group (TES) in which the rats were injected with saline and testosterone for 13 days; and the testosterone+dexamethasone group (TES+DEX) in which the rats were injected with dexamethasone and testosterone. The animals were weighed daily. 24 hours following the final injection, animals were weighed and sacrificed. Blood samples were withdrawn from the abdominal aorta and centrifuged at 3 000r/min for 10min. The supernatant was collected and stored at -20?C. Gastrocnemius muscle was removed, weighed and stored at -80?C. IGF-1 mRNA expression in skeletal muscle was determined by real-time PCR. IGF-1 protein expression in serum was determined by enzyme-linked immunosorbent assay (ELISA). Results Testosterone attenuated the body weight loss and gastrocnemius muscle weight loss in rats as a result of dexamethasone adminishation (P