To investigate the fate of composite skin comprising mixed keratinocytes seeded on acellular dermal matrix (ADM) after its transplantation to the wound. Newborn BALB/c and human keratinocytes were mixed in various ratios, seeded on the surface of ADM, and cocultured. The composite skin substitute were then grafted onto the full thickness skin wounds in BALB/c mice. The fate of human keratinocytes was observed. The results showed that the composite skin substitutes could close the full thickness wounds in BALB/c mice. Human keratinocytes were mainly located in the upper layer of the epidermis, and were gradually replaced by BALB/c keratinocytes. This indicated that the mixed culture of keratinocytes of two different species on ADM could close full thickness wounds, having the advantages such as saving the donor skin and shortening the culture time in vitro .

To reconstruct a composite skin substitute composed of keratinocytes and collagen sponge as dermal scaffold. Collagen was extracted from fresh porcine skin. After being mixed with chondroitin sulfate, it was frozen and dried under vacuum to form a spongy membrane. Keratinocytes were separated from the foreskin with the routine method, and they seeded on the collagen membrane. The keratocytes which were carried by the collagen sponge were cultured, and the growth and proliferation were observed. The result showed that keratinocytes could grow and proliferate to form a confluent layer after 2～3 weeks. It indicated the the collagen sponge membrane showed no toxicity to human epidermal cells, and it could be used as a dermal scaffold in the construction of a composite skin substitute.

To investigate the expression of epidermal growth factor (EGF) of EGF gene transfected keratinocytes in vivo and in vitro after grafting. EGF levels in the supernatant of the culture media of EGF gene transfected keratinocytes cultured for different lengths of time and different passages were determined with ELISA method. Then, the gene transfected keratinocytes were seeded on the surface of acellular dermal matrix, After culture, the composite skin substitutes were grafted onto the full thickness wounds in nude mice. Specimens were harvested at intervals after grafting and stained for EGF with immunohistochemistry. The results showed that keratinocytes transfected with EGF gene secreted EGF, which was detected in the supernatant of the culture, for 5 passages. Immunohistochemical staining method showed that EGF was expressed in the newly generated epidermis 1～3 weeks after grafting of the composite skin substitute. The data showed that gene transfected keratinocytes could express EGF stably in vivo and in vitro , which would be of benefit to the construction of the tissue engineering skin.

To study the method of preparing the composite skin composed of keratinocytes and acellular dermis, and to investigate the efficacy as well as its histological changes after being grafted on wounds of athymic mice. Compared with keratinocyte sheet grafting, the wounds grafted with composite skin had better healing rate, appearance and less wound contraction rate. Moreover, histological examination revealed fully differentiated epidermis, organized proliferated collagen fibres, and distinct reconstruction of epidermis-dermis junction in composite skin group, with absence of acute immuno-rejection response. As a new kind of skin substitutes, the composite skin can improve the quality of wound healing.

To investigate the possibility of constructing composite skin, keratinocytes were cultivated in vitro on the epidermal surface of cell free dermis prepared from pig skin.Keratinocytes grown on the dermal matrix were released at selected time points, followed by determining the proliferative capacity with cell number quantity and cell proliferation test. Cells attaching to the dermal matrix after it were seeded for 1 and 2 weeks were observed with histological section HE staining and electron microscopy scanning. Results showed that the number of keratinocytes was markedly increased with culture time. They maintained their proliferative potential after they were seeded on acellular xeno dermal matrix and reached a confluent monolayer or 3 to 6 layers at the 1st and 2nd week after seeding. The data showed that a living composite skin combined with keratinocytes and acellular dermal matrix could be successfully prepared in vitro.

To improve the quality of clinical teaching in burn surgery,79 students of Grade 2005 were randomly divided to problem-based learning(PBL)group and lecture-based learning(LBL) group.The teaching quality of two teaching methods were compared.The results showed that the average score,the score of teaching effectiveness appraisal targets in PBL group were sig-nificant higher than that in LBL group.This indicated that the teaching effectiveness of PBL was better than that of LBL,PBL should be applied in clinical teaching in burn surgery.

OBJECTIVETo investigate the practicability of a spongy collagen membrane as a dermal substitute.

METHODSPorcine skin collagen was harvested and mixed and precipitated with chondroitin-6-sulfate, and then lyophilized for 48 hours to form sheets of highly porous membrane. The collagen membrane was embedded subcutaneously in SD rat's skin. The histological compatibility, the vascularization degree and degradation status were determined periodically by means of tissue sampling.

RESULTSThe collagen membrane possessed some degree of strength and tenacity with a structure consisting of multidinous interconnecting pores. It was easy to manipulate. Experimental subcutaneous embedding in SD rats indicated that the membrane exhibited good tissue compatibility, strong tendency to vascularization, with no evidence of acute inflammatory reaction, and slow degradation rate.

CONCLUSIONSpongy collagen membrane might be an optimal dermal substitute for wound coverage.

Animals ; Collagen ; metabolism ; Dermatologic Surgical Procedures ; Rats ; Rats, Sprague-Dawley ; Skin ; blood supply ; Skin Transplantation ; Skin, Artificial ; Swine ; Tissue Engineering ; methods ; Transplantation, Heterologous

Objective:To evaluate the efficacy and safety of recombinant human acidic fibroblast growth factor( rh-aFGF)and re-combinant human basic fibroblast growth factor( rh-bFGF)in the treatment of deep second degree burn. Methods:A multicenter,pro-spective,randomized and double-blind clinical trial was conducted. Totally 216 cases of deep second degree burn were selected from five research centers and given appropriate antibiotics and nutritional supplement therapy. The wound of 108 cases in the observation group were rinsing with rh-aFGF(one bottle / 5cm2)according to the wound area at the time of admission followed by rh-aFGF daily spraying,3-4 press/cm2 ,6-8 times a day. The 108 patients in the control group were treated with rh-bFGF with the same regimen as the observation group. After the 30-day follow-up,the wound healing was evaluated in the two groups. Results:The complete healing time,debridement time,complete healing rate in 12 days and 15 days in the observation group were all better than those in the control group(P<0. 05). After the 7-day treatment,the level of leukocyte and seepage score of the observation group were both lower than those of the control group(P<0. 01). The moderate rate showed significant difference between the two groups(P<0. 05). Conclu-sion:rh-aFGF shows better clinical efficacy than rh-bFGF in the treatment of deep second degree burn with the similar safety.

OBJECTIVETo appraise the significance of extravascular lung water index (EVLWI), pulmonary vascular permeability index (PVPI), and intrathoracic blood volume index (ITBVI) in the differential diagnosis of the type of burn-induced pulmonary edema.

METHODSThe clinical data of 38 patients, with severe burn hospitalized in our burn ICU from December 2011 to September 2014 suffering from the complication of pulmonary edema within one week post burn and treated with mechanical ventilation accompanied by pulse contour cardiac output monitoring, were retrospectively analyzed. The patients were divided into lung injury group ( L, n = 17) and hydrostatic group (H, n = 21) according to the diagnosis of pulmonary edema. EVLWI, PVPI, ITBVI, oxygenation index, and lung injury score ( LIS) were compared between two groups, and the correlations among the former four indexes and the correlations between each of the former three indexes and types of pulmonary edema were analyzed. Data were processed with t test, chi-square test, Mann-Whitney U test, Pearson correlation test, and accuracy test [receiver operating characteristic (ROC) curve].

RESULTSThere was no statistically significant difference in EVLWI between group L and group H, respectively (12.9 ± 3.1) and (12.1 ± 2.1) mL/kg, U = 159.5, P > 0.05. The PVPI and LIS of patients in group L were respectively 2.6 ± 0.5 and (2.1 ± 0.6) points, and they were significantly higher than those in group H [1.4 ± 0.3 and (1.0 ± 0.6) points, with U values respectively 4.5 and 36.5, P values below 0.01]. The ITBVI and oxygenation index of patients in group L were respectively (911 197) mL/m2 and (136 ± 69) mmHg (1 mmHg = 0.133 kPa), which were significantly lower than those in group H [(1,305 ± 168) mL/m2 and (212 ± 60) mmHg, with U values respectively 21.5 and 70.5, P values below 0.01]. In group L, there was obviously positive correlation between EVLWI and PVPI, or EVLWI and ITBVI (with r values respectively 0.553 and 0.807, P < 0.05 or P < 0.01), and there was obviously negative correlation between oxygenation index and EVLWI, or oxygenation index and PVPI (with r values respectively -0.674 and -0.817, P values below 0.01). In group H, there was obviously positive correlation between EVLWI and ITBVI (r = 0.751, P < 0.01) but no obvious correlation between EVLWI and PVPI, oxygenation index and EVLWI, or oxygenation index and PVPI (with r values respectively -0.275, 0.197, and 0:062, P values above 0.05). The total area under ROC curve of PVPI value for differentiating the type of pulmonary edema was 0.987 [with 95% confidence interval (CI) 0.962-1.013, P < 0.01], and 1.9 was the cutoff value with sensitivity of 94.1% and specificity of 95.2% . The total area under ROC curve of ITBVI value for differentiating the type of pulmonary edema was 0.940 (with 95% CI 0.860-1.020, P < 0.01), and 1,077. 5 mL/m2 was the cutoff value with sensitivity of 95.2% and specificity of 88.2%.

CONCLUSIONSEVLWI, PVPI, and ITBVI have an important significance in the differential diagnosis of the type of burn-induced pulmonary edema, and they may be helpful in the early diagnosis and management of burn-induced pulmonary edema.

Blood Gas Analysis ; Blood Volume ; Burns ; complications ; Capillary Permeability ; Diagnosis, Differential ; Extravascular Lung Water ; Humans ; Lung ; blood supply ; Lung Injury ; physiopathology ; therapy ; Monitoring, Physiologic ; Pulmonary Edema ; diagnosis ; etiology ; ROC Curve ; Respiration, Artificial ; Retrospective Studies

A Chinese localization protocol on scar prevention and management is needed, due to the ethnic differences and complicated clinical environment. Therefore, the "Chinese Expert Consensus Report on Clinical Prevention and Treatment of Scar" was released in 2017, after two-year extensive discussions, among 12 independent experts in burn/trauma, plastic surgery and dermatology. A number of recommendations were put forward to keep pace with the times, and adapt to the current clinical situation in China. This review is focused on some sections of the Expert Consensus, including the classification, assessment, prevention and treatment of scar, and related novel techniques, along with a briefly introduction of the rationales and theoretical evidences underlying the consensus.