Isolation, culture and cryopreservation of cells derived from fetal appendages / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the optimal method for isolation, culture and cryopreservation of cells from fetal appendages, for the purpose of providing viable cells for tissue engineering, cell therapy and gene therapy.</p><p><b>METHODS</b>Trypsin dispersion method was used to isolate cells from human umbilical cord and placenta. The tissues from umbilical cord and placenta were cryopreserved with dimethylsulfoxide (DMSO) in different concentrations. Then the percentage of living cells in thawed tissues, and their micro-structure were observed and compared with fresh tissues under transmission electron microscope. The expression of cell immune phenotype before and after cryopreservation were detected with immuno-histochemistry method.</p><p><b>RESULTS</b>The percentage of living cells in human fresh umbilical cord was 67.0%, while that in cryopreserved umbilical cord was 23.4%, 55.5%, 48.8%, 31.8%, respectively in 5%, 10%, 15%, 20% of DMSO. The percentage of living cells in cryopreserved tissues was similar to that of fresh tissues when the volume percentage of DMSO was 10% (P > 0.05), and it was significantly different with that when volume percentage of DMSO was 5% and 20% (P < 0.01). The result by transmission electron microscope was coincident with the results shown above. The results were similar between placenta and umbilical cord. There was no obvious changes in immune phenotype of the tissue and cells after cryopreservation.</p><p><b>CONCLUSION</b>Cryopreservation with this method can isolate a large amount of cells from fetal appendages, with no changes in immune phenotype after cryopreservation, and the effect was best when the volume percentage of DMSO was 10%.</p>

Preventing scarring in split-thickness skin donor sites with epidermal grafting / 中华整形外科杂志

<p><b>OBJECTIVE</b>Introducing a new technique for preventing the scar growthing in split thickness skin donor sites using the great sheets of epidermis covering.</p><p><b>METHODS</b>The donor sites of split thickness skin were grafting with the great sheets of the epidermis, of the thickness about 0.07 approximately 0.12 mm, harvested by electrical power dermatome and fixed the edges of the epidermal sheet with the verges of donor wound together using the nanoparticles-Ag-gauze stripes adding the sutures or skin stapler, dressing the wounds with the nanoparticles-Ag-gauze using the tie-over technique, left the dressing entire for a 5-day period.</p><p><b>RESULTS</b>This method were used in a total of 209 donor sites of both the split-thickness skin and epidermis for 133 reconstructed sites of 118 cases from November 1999 to November 2003, and the smooth, near normal skin appearance without scarring were obtained in the split thickness skin donor sites, and the epidermal donor sites healed good enough 5 days after surgery, and skin appearance is near normal in 3 months later.</p><p><b>CONCLUSIONS</b>Covering the donor sites of split thickness skin with the large sheets of epidermis is an effective and useful method for preventing the scarring in the split thickness skin donor sites.</p>