Usage of intermingled skin allografts and autografts in a senior patient with major burn injury.

Mortality rate in older adults following extensive burn injury is extremely high, and management of these patients is challenging. One of the main problems is that autologous split-thickness skin grafts are scarce and the wounds cannot be covered quickly and effectively. Intermingled skin grafting is a low-tech and economic method, which not only maximizes the use of precious autologous skin but also prevents the wounds from infection and consumption. Herein we present a case of extensive burn injury in a 68-year-old female successfully treated with intermingled skin grafting. The patient was accidentally burned by gas flame, resulting in a major burn injury covering 80% of her total body surface area. Early burn wound excision was performed and the wound was temporarily covered with irradiated porcine skin in the first week after injury. Autologous stamp-like skin grafts were applied to the wound bed 4 weeks after injury. In this operation, the results were not satisfactory. The take rate of the skin grafts is only about 50%. We covered the wounds with intermingled skin allografts and autografts 8 weeks after injury: autografts (0.5 cm × 0.5 cm) + fresh close relative's allografts (1 cm × 1 cm) + cryopreserved allografts (2 cm × 2 cm).

[Analysis on the diagnosis and treatment of necrotizing fasciitis complicated with sepsis].

OBJECTIVE: To recognize the characteristics of necrotizing fasciitis patients complicated with sepsis and summarize the experience the treatment. METHODS: A retrospective study was conducted. The clinical data of 57 patients with necrotizing fasciitis complicated with sepsis admitted to Guangdong Provincial People's Hospital from July 2009 to December 2019 was analyzed by collecting such factors as gender, age, complications, infection sites, pathogens, surgery information, treatment options and outcome. The patients were divided into debridement group (n = 14) and control group (n = 43) according to whether the debridement was completed within 48 hours of admission, and the mortality during hospitalization between the two groups was compared. A telephone follow-up had been done to record the long-term outcome of these patients. RESULTS: Among 57 patients with necrotizing fasciitis complicated with sepsis, there were 43 males and 14 females with the average age of (57.9±12.1) years old. Most of the underlying diseases were diabetes mellitus (70.17%), other diseases included hypertension (8.77%), tumor chemotherapy (7.02%), liver disease (hepatitis, cirrhosis, 7.02%), coronary artery heart disease (3.51%), systemic lupus erythematosus (3.51%), etc. Most of the infection site was lower limbs (71.93%). There were 78 pathogens cultured in 57 patients, in which 52 were non-drug resistant bacteria (66.67%), and 26 were drug resistant bacteria (33.33%). There were 40 Gram positive (G+) bacteria (51.28%), 29 Gram negative (G-) bacteria (37.18%), 8 fungi (10.26%) and 1 mixed bacteria (1.28%). Finally, of 57 patients, 46 patients were cured, and 11 patients died with hospital mortality of 19.30%. Among 57 patients, the hospital mortality in the debridement group was significantly lower than that in the control group [0% (0/14) vs. 25.58% (11/43), P < 0.05]. Among the 46 cured patients, 11 had accepted amputations, accounting for 23.91%. In December 2020, 43 patients who were cured (3 patients were lost to follow-up) were followed up by telephone. Twenty-three patients were completely self-care, 9 patients were partly self-care, 8 patients were completely unable to take care of themselves, and 3 patients died. CONCLUSIONS: Necrotizing fasciitis with sepsis mostly occurs in people with weakened immunity, and has a high mortality and disability rate. Early identification and active surgical debridement may be the key to improve the treatment effect.

Renal dysfunction aggravated impaired cutaneous wound healing in diabetic mice.

Renal dysfunction has been associated with poor outcomes of wound healing in the diabetic population. The purpose of this study was to create an excisional wound healing model in diabetic mice with renal dysfunction to investigate the combined effects of diabetes and nephropathy on cutaneous ulcers. Renal impairment was introduced in diabetic db/db mice through unilateral nephrectomy and electrocoagulation of the contralateral kidney. Renal function was subsequently monitored with assays of blood urea nitrogen and spot urinary protein/creatinine ratio. After 8 weeks, splinted, full-thickness excisional wounds were created on the dorsal skin and harvested on postoperative days 7 and 14 for further evaluation of wound healing. Renal injury promoted the increase of blood urea nitrogen 3 weeks after initial operation, which was maintained at double the control level throughout the study, concomitantly leading to a significant increase of spot urinary protein excretion. Diabetic mice with renal injury displayed notably impaired wound healing processes, concurrent with reductions in cellular proliferation and angiogenesis, as well as increases in M1 polarized macrophages, infiltrated neutrophils, oxidative stress, and cellular apoptosis. Furthermore, quantitative polymerase chain reaction (qPCR) results displayed corresponding changes of related genes (TNF-α, IL-1ß, SOD2) in the wounds of renal injured db/db mice. Renal manipulation in this study accelerated the progress of renal impairment, which was demonstrated to aggravate impaired cutaneous wound healing in diabetic mice.

[Protective effects of valproic acid on gut barrier function after major burn injury and its mechanism].

OBJECTIVE: To investigate the potential protective effects of valproic acid (VPA) on gut barrier function after major burn injury in rats and its mechanism. METHODS: Forty male Sprague-Dawley (SD) rats were divided into sham + normal saline (NS), sham + VPA, scald + NS, and scald + VPA groups, with 10 rats in each group. Rat with 55% total body surface area (TBSA) third-degree severe-burns model was reproduced by immersing into 80 °C water, and the rats in sham groups were given sham-burns by immersing into 37 °C water. The rats after severe-burns were immediately treated with 0.25 mL of 300 mg/kg VPA or NS by subcutaneous injection. Rats were sacrificed at 2 hours and 6 hours after injury, and abdominal aortic blood and ileal tissue were harvested. The levels of vascular endothelial growth factor (VEGF) were determined by enzyme-linked immunosorbent assay (ELISA). The intestinal permeability was evaluated by fluorescein isothiocyanate-dextran (FITC-dextran) determination. The histomorphological changes in gut barrier were evaluated by Chiu grading system. Levels of acetylated lysine at the ninth position of histone 3 protein (Ac-H3K9), hypoxia-inducible factor 1α (HIF-1α), zona occludens 1 (ZO-1) and myosin light chain kinase (MLCK) were determined by immunofluorescence staining and Western Blot. RESULTS: Compared with sham + NS group, rats in scald + NS group showed intestinal mucosal damage 2 hours after burn injury, as well as increased mucosal permeability, protein expression levels of HIF-1α, VEGF, MLCK, and lowered levels of AC-H3K9 and ZO-1. These changes were much more prominent at 6 hours after injury. VPA treatment significantly attenuated the burn-induced intestinal damage. Compared with scald + NS group, the protective effects in scald + VPA group was not evident at 2 hours after injury; however, intestinal damage was much less severe at 6 hours after injury (Chiu score: 2.03±0.27 vs. 3.12±0.15), intestinal permeability was significantly decreased [FITC-dextran (µg/L): 709±76 vs. 1 138±75], histone acetylation was enhanced [Ac-H3K9 (gray value): 1.55±0.12 vs. 0.48±0.12], ZO-1 degradation was significantly inhibited (gray value: 0.69±0.12 vs. 0.43±0.16), the protein expression levels of VEGF and MLCK were significantly down-regulated [VEGF (ng/mg): 51.7±3.7 vs. 71.2±4.3, MLCK (gray value): 1.98±0.20 vs. 2.80±0.24], while the HIF-1α protein expression levels were significantly reduced at both 2 hours and 6 hours after injury (gray value: 2.50±0.39 vs. 3.88±0.42 at 2 hours, 1.83±0.42 vs. 4.42±0.41 at 6 hours, all P < 0.05). CONCLUSIONS: Severe burn injury can induce histone deacetylation, ZO-1 degradation and intestinal barrier dysfunction. VPA can improve the levels of histone acetylation and ZO-1, and protect intestinal epithelial barrier function. These may probably be mediated through inhibiting HIF-1α and its downstream gene VEGF and MLCK.

[Analysis of liver damage and reactivation of hepatitis B virus in hepatitis B surface antigen positive patients after extremely severe burn injury].

OBJECTIVE: To analyze the development of liver damage and reactivation of hepatitis B virus (HBV) during the treatment of extremely severe burn injury in HBsAg positive patients, in order to provide reference for prevention and treatment of liver damage in patients with HBV infection after extremely severe burn. METHODS: Medical records of 54 HBsAg positive patients after extremely severe burn injury admitted from January 2004 to December 2014 were retrospectively analyzed. Development of liver damage and HBV reactivation of these patients during the treatment were analyzed according to the classification of their gender, results of hepatitis B e antigen (HBeAg) and HBV DNA examinations on admission, and development of sepsis in the process of treatment. Data were processed with chi-square test. RESULTS: (1) The incidence of liver damage in the process of treatment of these patients was 85.2% (46/54). Among all the patients, the proportion of liver damage was 35/38 in male, which was significantly higher than that in female (11/16, χ² = 4.867, P<0.05). Liver damage was found in all of 26 patients who were HBeAg positive on admission, 34 patients who were HBV DNA positive on admission, and 36 patients who developed sepsis in the process of treatment; the proportions were significantly higher than those in patients who were HBeAg negative on admission (20/28), patients who were HBV DNA negative on admission (12/20), and patients who did not develop sepsis in the process of treatment (10/18), with χ² values respectively 11.801, 18.384, and 20.574, P values below 0.01. (2) The incidence of HBV reactivation in these patients was 29.6% (16/54). Among all the patients, the proportion of HBV reactivation was 13/38 in male and 3/16 in female, with no statistically significant difference between them (χ² = 0.656, P>0.05). The proportions of HBV reactivation in patients who were HBeAg positive on admission, patients who were HBV DNA positive on admission, and patients who developed sepsis in the process of treatment were respectively 13/26, 16/34, and 15/36, and they were significantly higher than those in patients who were HBeAg negative on admission (3/28), patients who were HBV DNA negative on admission (0/20), and patients who did not develop sepsis in the process of treatment (1/18), with χ² values respectively 9.979, 18.615, and 5.873, P<0.05 or P<0.01. CONCLUSIONS: Patients who are HBsAg positive, HBeAg positive, HBV DNA positive on admission, and develop sepsis in the process of treatment of extremely severe burn injury are more likely to develop liver damage and HBV reactivation. It is necessary to dynamically monitor the changes in HBV DNA and liver function, in order to identity the reactivation of virus.

Activation of sirtuin 1/3 improves vascular hyporeactivity in severe hemorrhagic shock by alleviation of mitochondrial damage.

Vascular hyporeactivity is one of the major causes responsible for refractory hypotension and associated mortality in severe hemorrhagic shock. Mitochondrial permeability transition (mPT) pore opening in arteriolar smooth muscle cells (ASMCs) is involved in the pathogenesis of vascular hyporeactivity. However, the molecular mechanism underlying mitochondrial injury in ASMCs during hemorrhagic shock is not well understood. Here we produced an in vivo model of severe hemorrhagic shock in adult Wistar rats. We found that sirtuin (SIRT)1/3 protein levels and deacetylase activities were decreased in ASMCs following severe shock. Immunofluorescence staining confirmed reduced levels of SIRT1 in the nucleus and SIRT3 in the mitochondria, respectively. Acetylation of cyclophilin D (CyPD), a component of mPT pore, was increased. SIRT1 activators suppressed mPT pore opening and ameliorated mitochondrial injury in ASMCs after severe shock. Furthermore, administration of SIRT1 activators improved vasoreactivity in rats under severe shock. Our data suggest that epigenetic mechanisms, namely histone post-translational modifications, are involved in regulation of mPT by SIRT1/SIRT3- mediated deacetylation of CyPD. SIRT1/3 is a promising therapeutic target for the treatment of severe hemorrhagic shock.

[Classification and management of sternal wound complications after cardiac surgery].

OBJECTIVE: To define the classification of sternal wound complications after cardiac surgery and to explore the appropriate surgical treatment. METHODS: Between July 2008 and January 2014, 260 patients with sternal wound complications after cardiac surgery were treated. There were 124 males and 136 females, aged 11-75 years (mean, 49.5 years). The disease duration was 13-365 days (mean, 26.6 days) with a wound length of 1-25 cm (mean, 13.4 cm). The wounds were divided into type I (n = 70), type II (n = 64), type III (n = 42), type IV (n = 78), and type V (n = 6) according to self-generated classification for sternal wound complications after cardiac surgery. After debridement, wounds of type I and type II were repaired with local flap transplantation; wounds of type III were repaired with local flap transplantation combined with butterfly sternal fixation (n = 28), with bilateral pectoralis muscle flap combined with butterfly sternal fixation (n = 11), and with bilateral pectoralis muscle flap (n = 3); wounds of type IV were repaired with bilateral pectoralis muscle flap (n = 65), rectus abdominis muscle flap (n = 5), and pedicled omental flap (n = 8); and wounds of type V were repaired with pedicled omental flap. RESULTS: All the operations were successfully performed. Three patients died after pedicled omental flap repair, including 1 case of type IV and 2 cases of type V. The hospitalization time were 4-86 days (mean, 18.3 days). Primary wound healing was obtained in 248 cases (96.5%); poor healing occurred in 9 patients, which were cured after second surgery in 8 cases and after the third surgery in 1 case. CONCLUSION: The surgical treatment based on self-generated classification is appropriate to sternal wound complications after cardiac surgery. It can provide clinical evidence for the choice of subsequent operation.

[Effect of bone marrow mesenchymal stem cells on lipopolysacharide-induced secretion of inflammatory cytokines in rat macrophages in vitro].

OBJECTIVE: To investigate the effect of bone marrow mesenchymal stem cells (BMSCs) on secretion of inflammatory cytokines in macrophages stimulated by lipopolysacharide (LPS). METHODS: Rat BMSCs and macrophages were isolated, cultured, and identified. The BMSCs and macrophages, cultured alone or in co-culture, were treated with LPS or PBS or without treatment and tested for interleukin-10 (IL-10) and tumor necrosis factor-α (TNF-α) concentrations in the supernatants at 1, 3, 5, 7, 12, and 24 h after the treatment using enzyme-linked immunosorbent assay. RESULTS: Exposure to LPS caused significantly increased IL-10 and TNF-α concentrations in the supernatant of cultured macrophages but not in BMSC culture. Macrophages co-cultured with BMSCs showed significantly lowered IL-10 and TNF-α secretions in response to LPS exposure as compared with the macrophages cultured alone. CONCLUSION: BMSCs can reduce LPS-induced secretion of inflammatory cytokines by the macrophages to ameliorate inflammatory reactions.

Atractyloside induces low contractile reaction of arteriolar smooth muscle through mitochondrial damage.

Atractyloside is the principal naturally occurring active ingredient in ethnomedicines and animal grazing forage. Evidence that atractyloside can induce opening of the mitochondrial permeability transition pore (mPTP) indicates that mitochondrial mechanisms may play an important role in pathophysiological lesions of the heart, liver and kidney after atractyloside poisoning. Therefore, in this study we investigated the association of atractyloside-induced mitochondrial damage in arteriolar smooth muscle cells (ASMCs) with contractile reaction. Atractyloside led to depolarized and swollen or damaged ASMC mitochondria, which might be related to the concentration-dependent induction of mPTP opening. Relative ATP content in ASMCs was significantly reduced by 48%, 63% and 66% of control when cells were treated with 7.5, 10, and 15 µm atractyloside for 10 min, respectively, and ASMCs were hyperpolarized. In addition, the contractile responsiveness of ASMCs was eventually weakened. These results suggest that atractyloside has a toxic effect on vasoreactivity, which is possibly related to mitochondrial damage.

[Clinical application of low-molecular-weight heparin (Fraxiparine) in rescuing venous crisis of island skin flap].

OBJECTIVE: To evaluate the clinical efficacy of low molecular weight heparin (Fraxiparine) in rescuing venous crisis of island skin flap. METHODS: Of the 73 patients with venous crisis of island skin flap, 47 received subcutaneous injection of low-molecular-weight heparin (group I) and 26 were treated with phlebotomy, local compression and topical application of unfractionated heparin solution gauze (group II). RESULTS: The flap survival ratio was (88.46∓8.64)% in group I and (38.37∓6.53)% in group II (P<0.001). At 0, 2, and 4 h after injection of low-molecular-weight heparin, the activated partial thromboplastin time (APTT) was obviously delayed (24.28∓6.71, 41.35∓7.64 and 32.34∓6.35, respectively, P<0.01), FXa:C level was significantly decreased (152.4∓30.7, 65.8∓24.4 and 83.4∓18.4, respectively, P<0.01), while FIIa:C level underwent no obvious alterations (155.70∓31.61, 143.20∓24.75, and 143.4∓23.35, respectively, P=NS). CONCLUSION: Fraxiparine has good antithrombotic efficacy in rescuing venous crisis of island skin flap without adverse effect on systemic coagulation.

Normal skin and hypertrophic scar fibroblasts differentially regulate collagen and fibronectin expression as well as mitochondrial membrane potential in response to basic fibroblast growth factor

Basic fibroblast growth factor (bFGF) regulates skin wound healing; however, the underlying mechanism remains to be defined. In the present study, we determined the effects of bFGF on the regulation of cell growth as well as collagen and fibronectin expression in fibroblasts from normal human skin and from hypertrophic scars. We then explored the involvement of mitochondria in mediating bFGF-inducedeffects on the fibroblasts. We isolated and cultivated normal and hypertrophic scar fibroblasts from tissue biopsies of patients who underwent plastic surgery for repairing hypertrophic scars. The fibroblasts were then treated with different concentrations of bFGF (ranging from 0.1 to 1000 ng/mL). The growth of hypertrophic scar fibroblasts became slower with selective inhibition of type I collagen production after exposure to bFGF. However, type III collagen expression was affected in both normal and hypertrophic scar fibroblasts. Moreover, fibronectin expression in the normal fibroblasts was up-regulated after bFGF treatment. bFGF (1000 ng/mL) also induced mitochondrial depolarization in hypertrophic scar fibroblasts (P < 0.01). The cellular ATP level decreased in hypertrophic scar fibroblasts (P < 0.05), while it increased in the normal fibroblasts following treatment with bFGF (P < 0.01). These data suggest that bFGF has differential effects and mechanisms on fibroblasts of the normal skin and hypertrophic scars, indicating that bFGF may play a role in the early phase of skin wound healing and post-burn scar formation.

Normal skin and hypertrophic scar fibroblasts differentially regulate collagen and fibronectin expression as well as mitochondrial membrane potential in response to basic fibroblast growth factor.

Basic fibroblast growth factor (bFGF) regulates skin wound healing; however, the underlying mechanism remains to be defined. In the present study, we determined the effects of bFGF on the regulation of cell growth as well as collagen and fibronectin expression in fibroblasts from normal human skin and from hypertrophic scars. We then explored the involvement of mitochondria in mediating bFGF-induced effects on the fibroblasts. We isolated and cultivated normal and hypertrophic scar fibroblasts from tissue biopsies of patients who underwent plastic surgery for repairing hypertrophic scars. The fibroblasts were then treated with different concentrations of bFGF (ranging from 0.1 to 1000 ng/mL). The growth of hypertrophic scar fibroblasts became slower with selective inhibition of type I collagen production after exposure to bFGF. However, type III collagen expression was affected in both normal and hypertrophic scar fibroblasts. Moreover, fibronectin expression in the normal fibroblasts was up-regulated after bFGF treatment. bFGF (1000 ng/mL) also induced mitochondrial depolarization in hypertrophic scar fibroblasts (P < 0.01). The cellular ATP level decreased in hypertrophic scar fibroblasts (P < 0.05), while it increased in the normal fibroblasts following treatment with bFGF (P < 0.01). These data suggest that bFGF has differential effects and mechanisms on fibroblasts of the normal skin and hypertrophic scars, indicating that bFGF may play a role in the early phase of skin wound healing and post-burn scar formation.

Mitochondrial injury underlies hyporeactivity of arterial smooth muscle in severe shock.

BACKGROUND: Our previous data showed membrane hyperpolarization of arteriolar smooth muscle cells (ASMCs) caused by adenosine triphosphate (ATP)-sensitive potassium channels (K(ATP)) activation contributed to vascular hyporeactivity in shock. Despite supply of oxygen and nutrients, vascular hyporeactivity to vasoconstrictor agents still remains, which may result from low ATP level. The study was designed to investigate shock-induced mitochondrial changes of rat ASMCs in the genesis and treatment of hypotension in severe shock. METHODS: The animals were divided into four groups: controls, hemorrhagic shock, CsA+shock (preadministration of cyclosporin A before bleeding), and ATR+CsA+shock (preadministration of atractyloside, followed by CsA and bleeding). ASMCs were isolated and the ultrastructure and function of ASMC mitochondria and the vasoresponsiveness to norepinephrine (NE) was measured on microcirculatory preparations. RESULTS: Ultrastructurally, the hemorrhagic shock group showed swollen mitochondria with poorly defined cristae. In this group, the number of ASMCs with low mitochondrial membrane potential (Δψ(m)) was increased by 49.7%, and the intracellular ATP level was reduced by 82.1%, which led to activation of K(ATP) plasma membrane channels with resultant ASMC hyperpolarization and low vasoreactivity. These changes were reduced in the CsA+shock group. When mitochondrial damage was aggravated by ATR in the ATR+CsA+shock group, the CsA did not protect. Compared to the shock group, vasoresponsiveness to NE was much improved in the CsA+shock group. CONCLUSIONS: Mitochondrial ASMC dysfunction is involved in the genesis of reduced vasoreactivity in severe shock. Mitochondrial protection may therefore be a new approach in the treatment of shock-induced hypotension.

[Establishment of a rat model of bone marrow mesenchymal stem cell transplantation for repairing full-thickness skin defect].

OBJECTIVE: To establish a rat model of full-thickness skin defect to receive bone marrow mesenchymal stem cell transplantation for wound repair. METHODS: A full-thickness skin defect measuring 4 cmx4 cm in 36 F344 rats, which were divided into 3 groups with the wound covered with alloskin graft, acellular dermal matrix, or petrolatum gauze. In vitro cultured BMSCs in the 5th passage were transplanted into the skin defect, and the time of wound dressing dissociation and number of transplanted Brdu-positive cells in the wound were observed 14 days later. RESULTS: The alloskin graft resulted in significantly longer time before dressing dissociation, with greater number of Brdu-positive cells in the wound than the other two wound dressings (P<0.001). The acellular dermal matrix showed better effect than petrolatum gauze in terms of the dressing dissociation time and the viable transplanted cell number in the wound. CONCLUSION: Alloskin graft can be ideal for covering the wound surface to protect the transplanted BMSCs in rats.

[Effects of citrus reticulata blanco extract on fibroblasts from human hypertrophic scar in vitro].

OBJECTIVE: To investigate the effects of citrus reticulata blanco extract on the proliferation and collagen metabolism of fibroblasts from human hypertrophic scar. METHODS: Human hypertrophic scar fibroblasts from two burn patients obtained from plastic surgery were cultured in vitro and divided into experimental group (n = 12, with basic culture medium and 2.5, 5.0, 10.0,25.0 mg/L citrus reticulata blanco extract, respectively, 3 bottles for each concentration of citrus reticulata blanco extract ), control group 1 (n = 3, with basic culture medium) , and control group 2 ( n = 3, with basic culture medium and 5% ethyl alcohol). The cell proliferation in each group was observed with MTT method, then the inhibition rate was calculated. Apoptosis and its index ( AI) in each group were determined after TUNEL staining . The changes in the content of ICTP and PINP in each group were observed by radioimmunity. RESULTS: The inhibition rate in the experimental group with the citrus reticulata blanco extract in concentration of 2. 5, 5.0, 10.0, 25. 0 microg/ ml were (7. 100+/-0.038)% , (8. 100+/- 0. 048)% , (10. 900+/-0. 055)%, (15.900+/-0. 097) %, respectively, which were significantly higher than those in other two groups ( P <0.05 ). The Al (69. 7% , 71.7%, 86.4% , 95.2% ), ICTP [(17.2+/-0.6), (18.3+/-0.6), (19.8+/-0.5), (23.2+/-0.6) microg/L] and PINP [ (101.7+/-1.4) , (107. 8+/-1. 1) , (111.6+/-1.2) , (124. 6+/-1.3) microg/L] in experimental group with the citrus reticulata blanco extract in concentration of 2.5, 5.0, 10.0 , 25.0 mg/L were also obviously higher than other two control groups( P <0.05) ,but these indices in control 1 group were similar to those in control 2 group( P >0. 05). CONCLUSION: The citrus reticulata blanco extract might be beneficial for the management of hypertrophic scar through inhibition of the proliferation of fibroblasts in hypertrophic scar, by promoting apoptosis and collagen degradation.

[Establishing a parabiosis animal model of two-way paradigm].

OBJECTIVE: To establish a parabiosis model between allogenic conspecific adult mice to study two-way paradigm. METHODS: Fifty-four female Balb/c mice and 54 male C57BL/6 mice were paired and equally divided into 3 groups, namely group 1 with normal saline (NS) injection, group 2 with injections of spleen cells and cyclophosphamide (CP), and group 3 injected with spleen cells, CP, and cyclosporin A (CsA). The treatments were performed by injecting the spleen cells from one of the mice in a pair into the other via tail vein and vise versa, and two days after the operation, CP (150 mg/kg) was injected intraperitoneally. Intraperitoneal CsA (30 mg/kg daily) injection was given starting from 2 days before till 7 days after the operation. Twelve of the 18 pairs of parabiosis mice in each group were separated after 1 week, and part of the skin were transplanted to each other. The maintenance of parabiosis was observed in the other 6 pairs of parabiosis mice were observed. Mixed lymphocyte reaction (MLR) and delayed-type hypersensitivity (DTH) were observed and studied in the separated mice. RESULT: The duration of parabiosis maintenance and skin survival of the group 3 was significantly longer than those in the other two groups, and group 3 showed suppressed MLR and DTH. CONCLUSION: With the application of immunosuppressants, we have successfully established the two-way paradigm model in mice.

[Application of laminar air flow techniques in burn treatment].

OBJECTIVE: To evaluate the value of laminar flow in the treatment of burns. METHODS: The air in the laminar flow chamber and the wound tissues of the patients were sampled for bacterial detection. The number and stains of bacterial colony from different classes of laminar air flow chambers at different time points were inspected and compared. RESULTS: The bacterial number was 0 in the laminar flow chamber of 1000 grade, which was obviously different from that in the public area. The mortality was obviously decreased in the laminar air flow chamber with shorter treatment time and hospitalization. No wound infection occurred and the wounds healed smoothly in all these patients. CONCLUSION: The application of laminar air flow can be helpful for the treatment of severe burns.

[Comparison of the effects of rhEGF with rhbFGF on the acceleration of wound healing].

OBJECTIVE: To investigate the mechanism and the accelerating effect of rhEGF and rhbFGF on wound healing. METHODS: Twelve New Zealand rabbits with 72 incised wounds on ventral side of 24 ears were randomly divided into two therapeutic groups (rhEGF of 10 ug/cm(2) and rhbFGF of 100 AU/cm(2)) and a control group (1% silver sulfadiazine cream, SD-Ag). The general conditions of the wound healing was observed grossly. Biopsies were harvested at different time points for the pathomorphological examination, the electron microscopic examination, and for assessment of integrin beta1 mRNA expression by in situ hybridization. RESULTS: The expressions of integrin beta 1 mRNA in two therapeutic groups were significantly higher than that of control group. The quality of the wound healing was improved in therapeutic group with its healing time shortened when compared with that in control group (P < 0.05). There was an obvious difference in the number of fibroblasts and capillary gemmules between the therapeutic and control groups (P < 0.05). CONCLUSION: The wound healing and quality could be improved by both rhEGF and rhbFGF, but rhbFGF seemed better to be employed during the early and middle stages of the wound repair for the growth of granulation tissue, while rhEGF should be applied at the late stage of wound repair to accelerate the re-epithelialization of the wound. Combined application of rhEGF with rhbFGF according to time effect could be more beneficial to the wound repair.

[A preliminary study on the identification and distribution of epidermal stem cells in different degrees of burn wounds in scalded rats].

OBJECTIVE: To investigate the distribution of epidermal stem cells (ESCs) in different degrees of burn wounds in scalded rats. METHODS: Thirty-two Sprague-Dawley (SD) rats were employed in the study. First degree (I), shallow (shallow II) and deep partial thickness (deep II) and full thickness burn wounds (III) were created on the rat skin. Burn wound samples were harvested at 24 postburn hours (PBHs) from all the wounds and were processed to tissue slices. The tissue slices were stained by immunohistochemistry technique. The expression and distribution of ESCs in different degrees of burn wounds were observed with integrins alpha 2 beta 1 and keratin 10 (K10) as first antibodies. RESULTS: K10 positive cells were found to distribute in the strata spinosum, granulosum and lucidum in the first degree burn wound (I) with large amounts of integrins alpha 2 beta 1 positive cells in the residual basal layer and skin appendages (hair follicles) in shallow partial thickness burn wound (shallow II degree), and there were less integrins alpha 2 beta 1 positive cells in the remaining skin appendages in deep dermis in deep partial thickness burn wound (deep II degree). Finally, integrins alpha 2 beta 1 positive cells were sparsely found in the III degree burn wound. CONCLUSION: The distribution of ESCs in burn wounds was closely related to the depth of burn wound. The residual ESCs might be the origin of burn wound regeneration and reepithelization.