Full Thickness Skin Expansion ex vivo in a Newly Developed Reactor and Evaluation of Auto-Grafting Efficiency of the Expanded Skin Using Yucatan Pig Model

BACKGROUND: Skin grafts are required in numerous clinical procedures, such as reconstruction after skin removal and correction of contracture or scarring after severe skin loss caused by burns, accidents, and trauma. The current standard for skin defect replacement procedures is the use of autologous skin grafts. However, donor-site tissue availability remains a major obstacle for the successful replacement of skin defects and often limits this option. The aim of this study is to effectively expand full thickness skin to clinically useful size using an automated skin reactor and evaluate auto grafting efficiency of the expanded skin using Yucatan female pigs. METHODS: We developed an automated bioreactor system with the functions of real-time monitoring and remote-control, optimization of grip, and induction of skin porosity for effective tissue expansion. We evaluated the morphological, ultra-structural, and mechanical properties of the expanded skin before and after expansion using histology, immunohistochemistry, and tensile testing. We further carried out in vivo grafting study using Yucatan pigs to investigate the feasibility of this method in clinical application. RESULTS: The results showed an average expansion rate of 180%. The histological findings indicated that external expansion stimulated cellular activity in the isolated skin and resulted in successful grafting to the transplanted site. Specifically, hyperplasia did not appear at the auto-grafted site, and grafted skin appeared similar to normal skin. Furthermore, mechanical stimuli resulted in an increase in COL1A2 expression in a suitable environment. CONCLUSION: These findings provided insight on the potential of this expansion system in promoting dermal extracellular matrix synthesis in vitro. Conclusively, this newly developed smart skin bioreactor enabled effective skin expansion ex vivo and successful grafting in vivo in a pig model.

Rapid Expansion and Auto-Grafting Efficiency of Porcine Full Skin Expanded by a Skin Bioreactor Ex Vivo

Full skin auto-grafts are required for reconstruction of skin burns and trauma scars. However, currently available clinical approaches such as sheet skin graft, mesh skin grafts, artificial skin graft, and in vivo skin expansion have limitations due to their potential danger for secondary damage and scar formation at the donor site, and discomfort during skin expansion. We developed an advanced bioreactor system and evaluated its function in skin expansion using porcine full skin. The reactor was designed as a pneumatic cylinder type, was programmed to adjust the pressure and the operating time. The system was composed of culture chamber unit, environmental control unit, and monitoring unit. Skins were expanded at 200 kPa pneumatic force and the expanded skins were analyzed by immunohistochemistry and histology. Furthermore we carried out auto-grafting experiment of the expanded skins in vivo using Yucatan pigs and skins were harvested and histologically analyzed after 8 weeks. The results showed that the bioreactor expanded skins to 160% in 4 hours. Histological analysis of the expanded skins revealed that epidermal cells and dermal fibroblasts were viable and remained integrity. The results of auto-grafting experiment indicated that fibrosis and scars were not detected in the grafted skins. This study demonstrates that the newly developed skin bioreactor enabled to obtain large sized full skin rapidly and successful grating.

Changes of Eating Habits of the Residents of Taean, Korea after the Herbei Oil Spill Accident Based on Focus Group Interviews / 대한지역사회영양학회지

Hazardous chemicals, such as polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs) and heavy metals, are known as being harmful to human health were included in oils released by the Herbei Spirit Oil Spill accident in December 2007. To investigate changes of eating habits by the exposure to harmful substances, we conducted 5 focus group interviews for residents at Taean coast areas, who had experienced the oil spill accident. Participants included 46 women (mean age: 57.2 +/- 10.9) who were mainly responsible for preparing family meals. Focus group discussions were audio-taped, transcribed and categorized by themes. Participants expressed more frequent illness symptoms such as dizziness, vomiting, visual loss, and skin diseases after the accident. They mentioned that their worries about economic hardship and worsened health status since the accident induced mental problems, such as depression about their children. Regarding eating habits, participants reported less intakes of fishes and meats and relatively more intakes of vegetables and kimchi due to the lack of household incomes after the accident. Although the participants had been used to collecting or catching fish or shellfish for their consumption previously, they mainly purchased these foods from local markets after the accident. Changes of eating habits induced by the accident included drinking boiled water and having steamed or fried seafood rather than raw seafood. Changes of food intakes occurred less frequently in older adults due to their long-term fixed eating habits, although they felt uncomfortable for having raw fish. The findings of this study clearly present that the exposure of hazardous substances by the oil spill accident had a significant impact on changes in eating habits besides economic, physical, and mental problems among the residents in Taean. Continuous health and nutrition monitoring and support are needed.

Incidental Dural Tear during Posterior Surgery of Degenerative Lumbar Disease / 대한척추외과학회지

STUDY DESIGN: A retrospective study. OBJECTIVE: To analyze the clinical features and prognosis of intraoperative incidental durotomy during posterior surgery for degenerative lumbar disease. In addition, we tried to evaluate clinical outcome and safety of skillful neglect of pin point dural tear. SUMMARY OF LITERATURE REVIEW : Incidental durotomy is one of the most common complications during the operation of degenerative lumbar disease. It may cause signs and symptoms of cerebrospinal fluid leakage and complications such as meningitis, wound infection, pseudomeningocele and fistula. From the literature review, primary repair is mandatory even in the case of pin point dural tear. MATERIALS AND METHODS: Seven hundred fifty-five patients with degenerative lumbar disease, who were operated posteriorly from Jan. 1990 to Feb. 2002, were reviewed retrospectively. Primary operations were 378 cases of laminectomy without instrumentation and 377 cases of decompression and instrumented fusion. Of these patients, 44 (6 percent) sustained an incidental dural tear. We analyzed the mechanisms of dural tear, intraoperative treatment, postoperative management and clinical outcome. RESULTS: Eight cases (2.1%) of dural tears occurred during discectomy, 36 (9.5%) during instrumentation and fusion, and 12 (20%) during revision surgery. Dural tears were treated intraoperatively by primary repair in 20 cases, by fascial graft in 2 and without repair (skillful neglect) in 22. There were no cases of persistent cerebrospinal fluid leakage or fistula formation, and the symptoms of cerebrospinal fluid leakage were transient. Of 36 patients followed for more than one year, 82% had good or excellent result. CONCLUSION: Incidental durotomy occurred in 5.8 percent of lower back surgery patients, and more frequently in revision surgery. Very small dural tears did not have significant influence on the clinical outcome, whether they were repaired or not. Skillful neglect of pin point dural tear may be a reasonable treatment option.