Preparation and properties of a novel carbon nanotubes/poly(vinyl alcohol)/epidermal growth factor composite biological dressing.

Wound dressings with drug delivery system have drawn increasing attention in skin damage recombination. Herein, a novel composite biological dressing was prepared and based on poly(vinyl alcohol) (PVA) combined with carbon nanotubes (CNTs) and epidermal growth factor (EGF) by electrospinning on gauze. The properties of the CNTs/PVA/EGF composite dressing were systemically investigated by general observation, and scanning electron microscopy (SEM). In vitro, the cytotoxicity of this dressing was investigated using a methyl thiazolyl tetrazolium (MTT) assay on L929 fibroblasts. In order to study the sustained release of EGF from this dressing, the concentration of EGF at different times was tested by ELISA. Furthermore, the biological activity of the released EGF was also evaluated using the MTT assay. Moreover, an in vivo experiment was conducted to observe whether this dressing was capable of improving healing in the model of wounded skin on rats. It was revealed that this dressing had a well-distributed microstructure by SEM. Additionally, the grade of cytotoxicity was low, and the EGF had a sustained release rate from this dressing. Furthermore, a maximum accumulative release rate of 12.47% was identified at 12 h, and was retained at 9.4% after 48 h. Simultaneously, the relative growth rate of L929 fibroblasts in the 12 h experimental group and 48 h group was 291.24 and 211.3%, respectively. Next, the efficacy of these products was evaluated in vivo using Sprague-Dawley rats with a skin injury model. The healing of wounded skin of rats was sped up by this dressing based on the gross and histological appearances. From 7 to 10 days, the wounds in the experimental group were almost healed. In conclusion, this CNTs/PVA/EGF dressing had a well-distributed structure and an ability to release EGF at a sustained rate with the activity being favorable. On the basis of those results, a positive influence of designed dressing for accelerated wound healing was confirmed.

Viability and Biomechanics of Bare Diced Cartilage Grafts in Experimental Study.

OBJECTIVE: To assess the viability and biomechanics of bare diced cartilage grafts. METHODS: Cartilage samples were collected from 1 ear in 15 rabbits as well as costal cartilage. Each rabbit was inserted bare diced- and single-strip costal-cartilage grafts, respectively, into paraspinal subcutaneous pockets: after euthanasia at 2 months, specimens were weighed, with diced cartilage grafts examined histomorphologically by hematoxylin-eosin staining, masson trichrome staining, and immunohistochemistry. Finally, biomechanical properties of grafts were assessed. RESULTS: Bare diced cartilage grafts were connected into an integrated mass after 2 months, and inward growth of fibrous tissues and angiogenesis were observed. Mean wet weights of diced cartilage grafts were 1.603 ±â€Š0.278 and 1.662 ±â€Š0.204 g pre- and postoperation, respectively; those of costal cartilage grafts were 0.053 ±â€Š0.008 and 0.058 ±â€Š0.008 g, respectively. In compression assays, mean modulus values of elasticity at yield in diced- and costal-cartilage grafts were 7.65 ±â€Š0.59 and 22.30 ±â€Š1.15 MPa, respectively (P < 0.05); mean stress values were 4.07 ±â€Š0.38 and 12.50 ±â€Š1.15 MPa, respectively (P < 0.05). In the tensile test, mean modulus values of elasticity at yield of diced- and costal-cartilage grafts were 4.70 ±â€Š0.78 and 10.59 ±â€Š1.39 MPa, respectively (P < 0.05), mean stress values were 0.82 ±â€Š0.05 and 1.76 ±â€Š0.21 MPa, respectively (P < 0.05). CONCLUSIONS: Diced cartilage grafts had favorable viability and growth. Despite reduced elasticity and stress values, they still can be served as substitute for supportive filling materials.

Acid-Alkali Resistance of New Reclaimed Tiles Containing Sewage Sludge Ash and Waste Glass.

In this study, properties of newly developed reclaimed tiles in a harmful environment were investigated. A portion of clay used to manufacture tiles was replaced with sewage sludge ash (SSA) and waste glass to produce the new reclaimed tiles. To investigate the effects of SSA and waste glass on the properties of the tiles, different specimens were blended and placed in acid-alkali solutions. The reclaimed tile specimens were manufactured by clay, 10% SSA, and five different mixes of waste glass replacement, namely, 0%, 10%, 20%, 40%, and 60%. These specimens were calcined at 1000 °C and subsequently underwent a series of tests, including TGA/DTA (thermogravimetric analysis/differential thermal analysis), SEM (scanning electron microscopy), XRD (X-ray diffraction), bending strength, weight loss, and porosity. Test results show that shortcomings associated with the introduction of the sludge ash were improved by the admixture of waste glass, especially in the aspects of shrinkage and bending strength. The study showed that the new reclaimed tiles performed relatively well in acid-alkali resistance tests but appeared to have better alkali resistance than acid resistance. It was also found that the optimal mix of such reclaimed tiles was 10% SSA, 10% waste glass, and 80% clay.

[Epidemiological investigation of burn inpatients in 6 hospitals of Hainan province: a retrospective analysis in 8 years].

OBJECTIVE: To analyze epidemiological characteristics of burn inpatients in Hainan province over 8 years. METHODS: Six thousand and ninety-nine burn patients admitted to 6 hospitals of Hainan province from January 2002 to December 2009 were enrolled in the study. The clinical data of these patients were analyzed retrospectively, including age, gender, injury cause, wound position, burn area, ailment prior to admission, admission time, medical insurance, length of hospital stay, and mortality rate, relationship among inpatient distribution, admission time, and ambient temperature at the time of admission. Data were processed with SPSS 13.0 software. RESULTS: There were more burn male patients than female, with ratio of 2.1: 1.0. Most patients were younger than 13 years (57.2%, 3488/6099). The most common burn area was smaller than or equal to 10% TBSA (67.4%, 4108/6099), and the fewest patients had burn areas of over 50% TBSA (2.0%, 121/6099). The main causative agents were hot liquid and flame, accounting for 71.5% (4358/6099), 17.9% (1092/6099), respectively. Most patients had injuries of more than two body areas (60.7%, 3705/6099), and lower extremity injury (17.1%, 1042/6099) was predominant in wound of single body area. Among 703 cases who had other ailments prior to admission (11.5%), the highest rate of prior ailments was found in patients older than 60 years (18.5%, 48/260), it was lowest in children younger than 1 year (8.0%, 32/398). The length of hospital stay was 1 to 375 day, and the admission time was 10 minutes to 90 days after burn. Total mortality rate was 0.4% (26 cases). The number of inpatients aged from 19 to 59 was obviously higher in months with high ambient temperature (from June to August), and for inpatients younger than 13 years the incidence of burn injury showed no obvious seasonal change. The inpatients who had medical insurance accounted for 10.9% (66/603) to 19.5% (121/619) from 2002 to 2005, which increased to 46.0% (372/808) in 2007 and 79.1% (869/1098) in 2009. CONCLUSIONS: For burn inpatients in Hainan province, the main injury cause of burn injury is hot liquid, the number of burn adults aged from 19 to 59 seems to increase in months with high ambient temperature, while the incidence of burn in children showed no obvious seasonal change. The number of inpatients and those with medical insurance showed a tendency of increase from 2005 to 2009 in Hainan province.

[Follow-up review on the long-term effect of composite transplantation of allogeneic acellular dermal matrix and split thickness skin autograft].

OBJECTIVE: To review the long-term clinical effect of composite transplantation of allogeneic acellular dermal matrix (ADM) and split thickness skin autograft (STSG). METHODS: Nineteen patients with 34 wounds transplanted with allogeneic ADM combined with STSG who were hospitalized from March 2001 to October 2008 were enrolled as composite transplantation group (CT). Another 9 patients with 11 wounds transplanted with STSG admitted within the same time frame were enrolled as control group (C). All patients were followed up for longer than 2 years. Color, evenness, texture, contracture, sensation, and complications of transplanted skin were assessed using a modified Manchester Scar Scale (1-4 scores, the higher the score, the poorer the situation). The scar formation on skin donor sites was assessed by the Vancouver Scar Scale. Patients' degree of satisfaction and health status during the transplantation period were investigated in the form of questionnaire. The skin tissue structure of 4 patients was observed with histological method. The joint range of motion was assessed by the neutral position before and after operation and at follow-up. Data were processed with nonparametric test, chi-square test or t test. RESULTS: (1) The evenness, contracture, and texture of transplanted skin in CT group scored (1.6 ± 0.5), (1.8 ± 0.8), and (1.5 ± 0.8), respectively, which were significantly lower than those in C group [(2.0 ± 0.7), (2.2 ± 0.9), and (2.3 ± 0.7), with Z value respectively -2.058, -2.220, -2.323, P values all below 0.05]. Scores of color, sensation, and complications of transplanted skin in two groups were close to each other (with Z value respectively -0.628, -0.428, -2.520, P values all above 0.05). (2) Mild scar formation was observed in one of the skin donor sites in CT group. (3) Information as obtained from questionnaire showed no statistical difference between two groups in pinching, itching, and satisfaction degree (with χ(2) value respectively 0.187, 0.019, 2.628, P values all above 0.05). (4) Nerve fibers were seen in hand tissue 2 years after operation. ADM did not induce severe inflammatory responses in the site of grafting. (5) Eleven joints in CT group recovered or improved in function; while the other two joints required secondary surgery. Obvious contracture was observed in the two joints in C group. CONCLUSIONS: Allogeneic ADM combined with STSG transplantation prevents scar contracture and has obvious effect in improving function and appearance. There is no problem in regard to safety for its existence in either adult or children.

[Survey on the bacterial flora and their resistance to antibiotics in hospitalized burn patients on tropical islands].

OBJECTIVE: To investigate the bacterial flora and their drug resistance in hospitalized burn patients on tropical islands. METHODS: Retrospective study was carried out to analyze pathogenic microorganisms and their drug resistance characteristics in 392 burn patients hospitalized during 2000-2005. RESULTS: (1) Totally 671 strains of bacteria were isolated, among which Pseudomonas aeruginosa, Staphylococcus aureus, Aerobacter cloacae and Acinetobacter species were predominant, but the isolation rate of Pseudomonas aeruginosa was declining compared with that in 1990's. (2) The resistance rate of Pseudomonas aeruginosa to imipenem and cefepime was 32.2% and 36.7% , respectively, while that to other antibiotics was above 80%. (3) Among 141 strains of Staphylococcus aureus, 89 strains (63.1%) of MRSA were isolated, and none of them were resistant to Vancomycin. CONCLUSION: Pseudomonas aeruginosa, Staphylococcus aureus, Aerobacter cloacae and Acinetobacter species were predominant in tropical islands. The species of the pathogens are changing . The drug resistance rates of Pseudomonas aeruginosa and Staphylococcus aureus are rather high.

[Repair of electric burn wound in the upper limbs with lateral intercostal perforator-based pedicled flap].

OBJECTIVE: To describe an operative method for the repair of electric burn wound in the upper limbs with lateral intercostal perforator-based pedicled flap, and to observe its clinical effect. METHODS: Intercostal artery perforator-based pedicled abdominal flap with the blood supply originating from the lateral perforator branches of the 7th-10th intercostal arteries were used to repair the wounds of 6 patients with burn wounds in elbows, forearm, wrists and palms. The pedicles were (16. 0 cm x 12. 0 cm) - (9. 0 cm x 7.0 cm) in area, and the pedicles were severed 18 to 21 days after the operation. The survival and the appearance of the flaps were observed after operation. RESULTS: The procedure was easy and safe, and there was reliable and adequate blood supply in the lateral intercostal perforator-based pedicled flap. All the flaps survived in 5 patients, except marginal necrosis (3.5 cm x 2. 0 cm) was found in the distal portion of flap because flap cutting exceeded the paraumbilical line. The appearance was satisfactory after operation. CONCLUSION: This flap is suitable for the repair of deep wounds in hands, forearms, and elbows.

[Reparation of deep burn wounds with different kinds of skin flaps in patients with electrical injury].

OBJECTIVE: To sum up the clinical experience in the reparation of burn wounds with different types of skin flaps in patients with severe electrical injury. METHODS: Free skin flap, axile island flap with vascular pedicle and muscular skin flap were employed to repair 64 wounds in 49 cases. RESULTS: Skin flap necrosis happened in 2 cases, congestion and necrosis at the edge of skin flaps in 4 cases, and complete survival of the skin flaps and primary healing of the wounds in the remaining cases. CONCLUSION: Reparation of wounds with proper skin flaps according to the degree of the electrical injury is effective and reliable, which might be beneficial to the prevention of necrobiosis and the infection in deep tissue.

[The clinical application on composite graft of acellular allo-dermal matrix and auto-microskin on escharectomy after deep burns].

OBJECTIVE: To present the clinical application of composite graft of acellular allo-dermis matrix (ADM) with thin auto-microskin on burn wound. METHODS: 8 inpatients with 18 full thickness skin burn wounds were transplanted with allo-ADM after eschar was excised, then the auto-microskin and allo-human skin were covered on the area of the matrix, the wound where no allo-ADM grafting were covered as control groups only with auto-microskin and allo-human skin. The area of donor to wound is 1:5 - 1:8. RESULTS: Survived rate of 18 pieces composite skin that allo-ADM with auto-microskin were grafted were 94%. After following up for 3 to 13 months, the skins of complex grifting had well elastic and smooth texture compared to auto-microskin grafted, they appeared less cicatrisation and ulceration. 3 months after operation, it was indicated by histological examination that tightknit the epithelial-dermal conjunction and epidermal papilla structure could be identified in the allo-ADM skin and there were orderly collagenous fibres, but scar skin structure was observed in that auto-microskin grifted area. CONCLUSION: The graft effectiveness of allo-ADM and auto-microskin was better than that of auto-microskin, and this method could be used on major deep burn wound healing.