Analysis of the Factors Affecting Bone Union after Open-Wedge High Tibial Osteotomy and Graft Material for Lateral Cortex Fractures / 대한정형외과학회잡지

PURPOSE: The purpose of this study was to analyze patient factors including smoking, body mass index, correction angle, graft material, presence of lateral cortex fracture, and age for the effect on bone union after open-wedge high tibial osteotomy and the effect of graft material used for lateral cortex fractures. MATERIALS AND METHODS: This retrospective study was conducted on 54 patients and 58 cases with osteoarthritic change Kallgren-Lawrence grade 2 or less from May 2012 to June 2014. Average follow-up period was 22 months (14–38 months). The patients were divided into two groups according to patient related factors and graft materials (allograft, n=6; beta-tricalcium phosphate [β-TCP], n=6) used for lateral cortex fractures and were analyzed for the relationship with bone union after open-wedge high tibial osteotomy. Radiographic and clinic analyses were performed, and van Hemert grading was used for grading bone union at 6 weeks, 3 months, 6 months, and 1 year postoperatively. RESULTS: The non-smoking group and the group without lateral cortex fracture showed significantly higher bone union rates than the control group. No significant clinical or radiological difference was observed between the two groups in 12 cases and the allograft group showed significantly higher rates of union at 6 months and 1 year postoperatively according to the van Hemert grading. CONCLUSION: Smoking and the presence of a lateral cortex fracture is a risk factor for nonunion in medial open-wedge high tibial osteotomy. The use of allograft material rather than β-TCP for lateral cortex fractures is thought to result in better bone union.

Biochemical properties of full-length hepatitis C virus RNA-dependent RNA polymerase expressed in insect cells

The hepatitis C virus (HCV) RNA-dependent RNA polymerase, NS5B protein, is the key viral enzyme responsible for replication of the HCV viral RNA genome. Although several full-length and truncated forms of the HCV NS5B proteins have been expressed previously in insect cells, contamination of host terminal transferase (TNTase) has hampered analysis of the RNA synthesis initiation mechanism using natural HCV RNA templates. We have expressed the HCV NS5B protein in insect cells using a recombinant baculovirus and purified it to near homogeneity without contaminated TNTase. The highly purified recombinant HCV NS5B was capable of copying 9.6-kb full-length HCV RNA template, and mini-HCV RNA carrying both 5'- and 3'-untranslated regions (UTRs) of the HCV genome. In the absence of a primer, and other cellular and viral factors, the NS5B could elongate over HCV RNA templates, but the synthesized products were primarily in the double stranded form, indicating that no cyclic replication occurred with NS5B alone. RNA synthesis using RNA templates representing the 3'-end region of HCV minus-strand RNA and the X-RNA at the 3'-end of HCV RNA genome was also initiated de novo. No formation of dimersize self-primed RNA products resulting from extension of the 3'-end hydroxyl group was observed. Despite the internal de novo initiation from the X-RNA, the NS5B could not initiate RNA synthesis from the internal region of oligouridylic acid (U)20, suggesting that HCV RNA polymerase initiates RNA synthesis from the selected region in the 3'-UTR of HCV genome.