OBJECTIVE: To explore the feasibility of reconstructing tissue engineered vessel in vitro. METHODS: Bovine endothelial cells were isolated from calf thoracic aorta by enzyme digestion methods and subcultured and purified. The endothelial cells of the 3rd to 7th passages were seeded into the inner surface of tubular scaffold material by polyglycolic acid(PGA) coated with cross-linked collagen, and cultured in vitro for 10 days using dynamic rotation culture technique. Scanning electron microscopy was used to analyse the morphological characteristics, and prostacyclin released by endothelial cells was measured by radioimmunoassay of 6-keto-prostaglandin F1 alpha. RESULTS: The VIII factor staining of cultured endothelial cells was positive. The endothelial cells adhered well on the inner surface of tubular scaffold material with confluent monolayer covering(91.2 +/- 1.5)%. The endothelialized model released prostacyclin at a rate of (4.6 +/- 0.5) micrograms/cm2.min. There was significant difference to control group (P lt; 0.05). CONCLUSION: The PGA coating with collagen is an ideal scaffold for endothelial cells, the coverage rate is increased through dynamic rotation culture technique. It will lay a good foundation for architecture of a laminated structure of tissue engineered vessel.
OBJECTIVE To repair facial and neck scar using tissue expanding technique. METHODS From January 1991 to January 1995, 16 cases with facial and neck scar were treated. Multiple tissue expanders were put under the normal skin of facial and neck area, after being fully expanded, the scars were excised and the expended skin flaps were transplanted to cover the defects. The size and number of tissue expanders were dependent on the location of the scars. Normally, 5 to 6 ml expanding volume was needed to repair 1 cm2 facial and neck defect. The incisions should be chosen along the cleavage lines or in the inconspicuous area, such as the nasolabial fold or submandibular region. The design of flap was different in the face and in the neck. In the face, direct advanced flap was most common used, whereas in the neck, transposition flap was often used. Appropriate tension was needed to achieve smooth and cosmetic effect. It was compared the advantages and disadvantages of several methods for repair of the defect after facial and neck scar excision. RESULTS Fifteen cases had no secondary deformity after scar excision. Among them, 1 case showed blood circulation disturbance and cured through dressing change. Ten cases were followed up and showed better color and texture in the flap, and satisfactory appearances. CONCLUSION Tissue expanding technique is the best method for the repair of facial and neck scar, whenever there is enough expandable normal skin.