Daizhi Peng

Characteristics of burn deaths from 2003 to 2009 in a burn center: A retrospective study

Mortality remains one of the most important end-point quality control parameters to evaluate a burn care system. We retrospectively reviewed the characteristics and multiple organ dysfunction syndrome (MODS) patterns of burn deaths in our center from January 2003 to December 2009. The mortality rate during this time period was 2.3%. Fifty-six patients died, including 49 males and 7 females. The mean survival time was 28.45 ± 24.60 days. The burn percentage was (76.70 ± 26.86) % total burn surface area (TBSA), with (27.74 ± 24.95) % deep-partial thickness burns and (46.88 ± 33.84) % full-thickness burns. Inhalation injury was diagnosed in 36 (64.29%) patients. Patients who had undergone an operation, particularly in the first week post-burn, had a significantly longer survival time. An average of 5.50 ± 1.35 malfunctioning organs per patient and a mean sequential organ failure assessment (SOFA) score of 13.91 ± 3.65 were observed. The most frequently malfunctioning organs were involved in the respiratory, hematologic, circulatory, and central nervous systems. Most of the organ damage occurred during the first week post-burn, followed by 4 weeks later, with relatively less organ damage observed in the third week. Among patients with a TBSA over 50%, non-survivors had larger burn sizes (particularly larger full-thickness burns) and a higher incidence of inhalation injury compared with survivors; non-survivors were also more likely to have microorganism-positive blood and sputum cultures. In conclusion, burn deaths are related to a higher burn percentage, inhalation injury, MODS, and infection. Early operation may help improve survival duration.

Guidelines for burn rehabilitation in China

Quality of life and functional recovery after burn injury is the final goal of burn care, especially as most of burn patients survive the injury due to advanced medical science. However, dysfunction, disfigurement, contractures, psychological problems and other discomforts due to burns and the consequent scars are common, and physical therapy and occupational therapy provide alternative treatments for these problems of burn patients. This guideline, organized by the Chinese Burn Association and Chinese Association of Burn Surgeons aims to emphasize the importance of team work in burn care and provide a brief introduction of the outlines of physical and occupational therapies during burn treatment, which is suitable for the current medical circumstances of China. It can be used as the start of the tools for burn rehabilitation.

Effect of Mixed Transplantation of Autologous and Allogeneic Microskin Grafts on Wound Healing in a Rat Model of Acute Skin Defect

The treatment of extensive thermal injuries with insufficient autologous skin remains a great challenge to burn surgeons. In this study, we investigated the influence of the ratio of autologous and allogeneic tissue in mixed microskin grafts on wound healing in order to develop an effective method for using limited donor skin to cover a large open wound. Four different mixtures were tested: autologous microskin at an area expansion ratio of 10∶1 with allogeneic microskin at an area expansion ratio of 10∶1 or 10∶3 and autologous microskin at an expansion ratio of 20∶1 with allogeneic microskin at an expansion ratio of 20∶3 or 20∶6. Wound healing, wound contraction, and integrin β1 expression were measured. Mixed microskin grafting facilitated wound healing substantially. The mixture of autologous microskin at an expansion ratio of 10∶1 with the same amount of allogeneic microskin achieved the most satisfactory wound healing among the 4 tested mixtures. Histological examination revealed the presence of obviously thickened epidermis and ectopic integrin β1 expression. Keratinocytes expressing integrin β1 were scattered in the suprabasal layer. Higher levels of integrin β1 expression were associated with faster wound healing, implying that ectopic expression of integrin β1 in keratinocytes may play a pivotal role in wound healing. In conclusion, this study proves that this new skin grafting technique may improve wound healing.

Screening of HaCaT Clones for CCL20 Gene Knockout and Preliminary Exploration of Gene-Targeting Vector Transfection Approaches in this Cell Line

Background Inhibition of CC chemokine ligand 20 (CCL20), which is expressed by human keratinocytes after proinflammatory cytokine stimulation, may reduce migration of recipient Langerhans cells into tissue-engineered allogeneic skin grafts and minimize immune rejection by the recipient. Here, we screened CCL20 gene knockout clones in the human immortalized skin keratinocyte line HaCaT and tested multiple transfection methods for optimal efficiency. Material/Methods The CCL20 gene was PCR amplified from HaCaT genomic DNA. Both the short arm (1,969 bp) and long arm (2,356 bp) of human CCL20 were cloned into ploxP-targeting vectors at either side of the neomycin resistance cassette, respectively. The resulting ploxP-hCCL20-targeting vector was linearized and electroporated into HaCaT. The positive HaCaT clones were screened under the pressure of both G418 and GANC, and identified by PCR and Southern blot. The ploxP-hCCL20-EGFP fluorescent expression vector was also constructed and transfected into 293FT and HaCaT cells by jetPEI liposome and nucleofection electroporation for evaluating the transfect efficiency under fluorescent microscope. Results The replacement targeting vector ploxP-hCCL20 (11.9 kb) for exon 2 of the human CCL20 gene was successfully constructed and transfected into HaCaT cells. The selected HaCaT clones did not show any evidence of CCL20 gene knockout by either PCR or Southern blot analysis. We also successfully constructed a fluorescent expression vector ploxP-hCCL20-EGFP (13.3 kb) to assess possible reasons for gene-targeting failure. Transfection efficiencies of ploxP-hCCL20-EGFP into 293FT and HaCaT cell lines by jetPEI liposome were 75.1±3.4% and 1.3±0.2%, respectively. The transfection efficiency of ploxP-hCCL20-EGFP into HaCaT cells using nucleofection electroporation was 0.3±0.1% (P=0.000), but the positive control vector pmaxGFP (3,490 bp) using the same method was 38.3±2.8%. Conclusions Overall low transfection efficiencies of ploxP-hCCL20-EGFP into HaCaT cells, regardless of transfection method, may either be due to the high molecular weight of the vector or to the fact that this particular cell line may be inherently difficult to transfect.

Changes in the inositol lipid signal system and effects on the secretion of TNF-α by macrophages in severely scalded mice.

AIM In order to study the mechanism of abnormal macrophage (Mϕ) function in pro-inflammatory cytokine changes after burn, the inositol lipid signal system and its role in tumour necrosis factor-alpha (TNF-α) secretion by peritoneal Mϕs was observed in severely scalded mice. METHODS Eighteen percent total body surface area (TBSA) full-thickness scalded mice were used as animal model in this experiment. Peritoneal Mϕs stimulated by lipopolysaccharide in vitro were collected at different time intervals (0, 2, 6, 12, 24 and 48 after burn hour (PBH)), The activities of phosphatidylinositol-phospholipase C (PI-PLC), inositol-1, 4,5, -triphosphate (IP(3)), protein kinase C (PKC), diacylglycerol (DAG) and TNF-α and the level of Ca(2+) concentration in peritoneal Mϕs were measured, and the effects of specific PKC inhibitor H-7 and calmodulin antagonist W-7 on the production of TNF-α were also observed. RESULTS After scald, increased activities of TNF-α and PLC of Mϕ were observed and peaked at 12 PBH. The activities of DAG and IP(3) and the concentration of Ca(2+) were markedly increased and reached their peaks at 24 PBH simultaneously. Membrane PKC activity was up-regulated after scald and showed a positive correlation with the change of DAG (r=0.83, P<0.05). There was also positive correlation between IP(3) and Ca(2+) activity (r=0.946, P<0.01). When 12 PBH was chosen as the time point for in vitro intervention with the pre-treatment by H-7, both membrane PKC and TNF-α activity decreased significantly. There was no obvious change of TNF-α activity with the application of W-7. CONCLUSIONS These results indicated that the abnormal activity of TNF-α of Mϕs might be regulated by the inositol lipid signal system following severe burn. The DAG-PKC signal pathway showed closer relationship than IP(3)-Ca(2+) in TNF-α production and could be the optimal target in the prevention and treatment of the systemic inflammatory response syndrome.

Determination of nuclear transcription factor activity using a modified electrophoretic mobility shift assay

A determinacao da alteracao na mobilidade eletroforetica (EMSA), o metodo de mais ampla utilizacao para o estudo das interacoes proteinaacidos nucleicos, e tediosa e dificil de dominar. De acordo com os protocolos dacumentados e com base em nossa pratica, nos modificamos os diversos processos principais dessa determinacao incluindo no que diz respeito a extracao de proteiinas nucleicas, marcacao das provas e radioautografia. A determinacao modificada requer menor tempo, simplifica a extracao de acidos nucleicos, eleva a radioatividade da prova marcada, evita o processo tedioso de secagem do gel e produz claras imagens. Seus resultados sao comparaveis, reproduziveis e estaveis, merecendo, desse modo, ampla aplicacao.

Guideline for diagnosis, prophylaxis and treatment of invasive fungal infection post burn injury in China 2013

Invasive fungal infection is one of the major complication of severe burns which can induce local or systemic inflammatory response and cause serious substantial damage to the patient. The incidence of fungal infection for burn victims is increasing dramatically during recent years. This guideline, organized by Chinese Society of Burn Surgeons, aims to standardize the diagnosis, prevention and treatment of burn invasive fungal infection. It can be used as one of the tools for treatment of major burn patients.

Sub-cytotoxic concentrations of ionic silver promote the proliferation of human keratinocytes by inducing the production of reactive oxygen species

Silver-containing preparations are widely used in the management of skin wounds, but the effects of silver ions on skin wound healing remain poorly understood. This study investigated the effects of silver ions (Ag+) on the proliferation of human skin keratinocytes (HaCaT) and the production of intracellular reactive oxygen species (ROS). After treating HaCaT cells with Ag+ and/or the active oxygen scavenger N-acetyl cysteine (NAC), cell proliferation and intracellular ROS generation were assessed using CCK-8 reagent and DCFH-DA fluorescent probe, respectively. In addition, 5-bromo-2-deoxyUridine (BrdU) incorporation assays, cell cycle flow cytometry, and proliferating cell nuclear antigen (PCNA) immunocytochemistry were conducted to further evaluate the effects of sub-cytotoxic Ag+ concentrations on HaCaT cells. The proliferation of HaCaT cells was promoted in the presence of 10–6 and 10–5 mol/L Ag+ at 24, 48, and 72 h. Intracellular ROS generation also significantly increased for 5–60 min after exposure to Ag+. The number of BrdU-positive cells and the presence of PCNA in HaCaT cells increased 48 h after the addition of 10–6 and 10–5 mol/L Ag+, with 10–5 mol/L Ag+ markedly increasing the cell proliferation index. These effects of sub-cytotoxic Ag+ concentrations were repressed by 5 mmol/L NAC. Our results suggest that sub-cytotoxic Ag+ concentrations promote the proliferation of human keratinocytes and might be associated with a moderate increase in intracellular ROS levels. This study provides important experimental evidence for developing novel silver-based wound agents or dressings with few or no cytotoxicity.