Osteogenic Differentiation of Human Adipose-derived Stem Cells within PLGA(Poly(D,L-lactic-co-glycolic acid)) Scaffold in the Nude Mouse

PURPOSE: The object of this study was to evaluate the development of continuous osteogenic differentiation and bone formation after the subcutaneous implantation of the tissue-engineered bone, in vitro. METHODS: Human adipose-derived stem cells were obtained by proteolytic digestion of liposuction aspirates. Adipose-derived stem cells were seeded in PLGA scaffolds after being labeled with PKH26 and cultured in osteogenic differentiation media for 1 month. The PLGA scaffolds with osteogenic stimulated adipose-derived stem cells were implanted in subcutaneous layer of four nude mice. Osteogenesis was assessed by RT-PCR for mRNA of osteopontin and bone sialoprotein(BSP), and immunohistochemistry for osteocalcin, and von Kossa staining for calcification of extracellular matrix at 1 and 2 months. RESULTS: Implanted PLGA scaffold with adipose-derived stem cells were well vascularized, and PLGA scaffolds degraded and were substituted by host tissues. The mRNA of osteopontin and BSP was detected by RT-PCR in both osteogenic stimulation group and also osteocalcin was detected by immunohistochemistry at osteogenic stimulation 1 and 2 months, but no calcified extracellular deposit in von Kossa stain was found in all groups. CONCLUSION: In vivo, it could also maintain the characteristics of osteogenic differentiation that adipose- derived stem cells within PLGA scaffold after stimulation of osteogenic differentiation in vitro, but there were not normal bone formation in subcutaneous area. Another important factor to consider is in vivo, heterologous environment would have negative effect on bone formation as.[p1]

Experience of Striae Distensae After Tissue Expansion

No abstract available.

Retrospective study on the local redurrence and distant metastasis of malignant skin tumors

The results of a retrospective study on 197 cases of malignant skin tumors, which were operated from July 1991 to June 1996 were presented. 1. Primary malignant skin tumors in our series included basal cell carcinoma (42%), squamous cell carcinoma (39%), melanoma (7%). Eighty five percentage of them were developed after 5th decade. There was a slight male preponderance (male to female ratio; 1.2:1). 2. seventy five percentage of malignant skin tumors were occurred in the head and neck. However 34% of squamous cell carcinoma occurred in the extremities. 3. Overall recurrence rate was 7.1% and overall metastasis rate was 7.6%. Seven cases (8.5%) of basal cell carcinoma were recurred without metastasis and seven cases (53.8%) of melanoma were meatastasized without recurrence. 4. Overall recurrence occurred at average 27 months after primary resection and 79% of them occurred in the head and neck. Among 14 recurred tumors, one recurred secondarily and three were metastasized elsewhere. 5.Two thirds of metastasis occurred within one year of resection. Mortality rate in the patients with metastasis was 40%. Metastases involved multiple organs and involved lymph nodes most frequently. 6.Fifteen patients with metastasis were treated with surgery alone (2 cases), surgery and adjuvant therapy (3 cases), radiation and/or chemolherapy without surgery (6 cases), and no therapy(4 cases).

A CASE OF CARCINOMA EX PLEOMORPHIC ADENOMA OF PALATE

Carcinoma ex pleomorphic adenoma is a very rare malignant tumor arising in the salivary gland and mainly in the parotid gland. It is highly malignant but asymptomatic, painless and has space occupying lesion sometimes. The metastasis is common(70%) and the prognosis is relatively poor. Although there is no definite treatment modality, the combined surgical intervention and the postoperative radiation therapy has been recommended. We treated a case of carcinoma ex pleomorphic adenoma of the palate with local excision, skin graft and postoperative radiation therapy