Differentiation of human telomerase reverse transcriptase immortalized human marrow mesenchymal stem cell into chondrocyte / 中华外科杂志

<p><b>OBJECTIVE</b>To establish an immortalized marrow mesenchymal stem cell line to facilitate advances in cartilage engineering research.</p><p><b>METHODS</b>Human telomerase reverse transcriptase (hTERT) cDNA was transferred into primary human marrow mesenchymal stem cells (hMSC) by retroviral vector pLEGFP-C1-hTERT. Subsequently G418 resistant cell clone was screened and expanded for further studies. hMSC biomarkers and hTERT expression were confirmed by examination. Transfected hMSC was induced to differentiate into chondrocyte using TGF-P1 and dexamethasone.</p><p><b>RESULTS</b>Up-regulated hTERT expression was detected in transfected hMSC. hMSC-hTERT cells could be induced to differentiate into chondrocyte. Higher telomerase activity in transfected cells was maintained for 50 population doublings so far. Collagen II could be detected in induced transfected hMSC by immunocytochemical and hybridization in situ.</p><p><b>CONCLUSIONS</b>Ectopic expression of hTERT can effectively immortalize hMSC in vitro. Immortalized hMSC can be induced to differentiate into chondrocyte under certain condition. It may be an ideal target of further studies in cartilage engineering.</p>

Arthroscopic assisted diagnosis and treatment of knee extension limitation / 中华外科杂志

<p><b>OBJECTIVE</b>To figure out the incidence and etiology of knee extension limitation and then to find out the proper methods of arthroscopic assisted diagnosis and treatment.</p><p><b>METHODS</b>We reviewed 303 cases of arthroscopic assisted operation from January to October 2003, 95 cases of which suffered from knee extension limitation before operation, including 54 male and 41female and the mean age was 36.2 years old. The direct reasons of knee extension limitation were identified by routine arthroscopic examination and operations were carried out according to results of the examination.</p><p><b>RESULTS</b>Incidence of knee extension limitation in this group of patients was 31.4%. Trauma, mainly meniscus and ligament injury accounted for 67.4%, which was the most common reason of knee extension limitation. Acute or chronic arthritis like degenerative arthritis, non-specific synovitis, synovial chondromatosis, rheumatoid arthritis, pigmented villonodular synovitis, gouty arthritis and acute pyogenic arthritis formed another common reason. The follow-up period ranged from 3 to 20 months, average 13.3 months. 82 cases gained full extension immediately after operation, 9 cases gained full extension after 3 weeks rehabilitation post-operation, 4 cases did not gain full extension 1 year after operation, recurrence was observed in 4 cases.</p><p><b>CONCLUSIONS</b>Arthroscopy is the best method for diagnosis of knee extension limitation at present. Satisfactory results can be expected after early arthroscopic assisted treatment.</p>