Objective To assess the effect of 5-azacytidine (5-AZ) on the expressions of atrial natriuretic peptide (ANP) and β-myosin heavy chain (β-MHC) genes in cultured rat bone marrow stromal cells (BMSCs). Methods Neonatal rat cardiomyocytes and adult rat BMSCs were isolated and cultured. BMSCs were incubated with 5-AZ and (or) myocardiocytes culture medium. RT-PCR was used to measure the expressions of cardiac ANP and β-MHC genes. Results Normally cultured rat BMSCs didn't express cardiac ANP or β-MHC. After inducing by 5-AZ, rat BMSCs expressed ANP or β-MHC. The myocardiocytes culture medium enhanced expression of β-MHC, but didn't affect the expression of ANP. Conclusions The 5-AZ induces the rat BMSCs to express either cardiac ANP or β-MHC, and the former could be enhanced by cardiomyocytes culture medium.

Objective To investigate the clinical results of bilateral transpedicular kyphoplasty for the osteoporotic vertebral compression fractures with single balloon. Methods From March 2002 to February 2004, percutaneous bilateral transpedicular kyphoplasty with single balloon was performed in 15 patients, who presented with painful vertebral compression fractures. In the group, there were 6 vertebrae of 6 males and 11 vertebrae of 9 females, and the average age of the patients was 70.5 years with a range of 62 to 82 years. 17 osteoporotic vertebral compression fractures, which involved 8 T12, 7 L1, 1 T8 and 1 T11, were treated. Osteoporosis was identified in all cases by the measurement of lumbar bone mineral density (BMD) and the evaluation of radiographs. The average BMD was 0.603 g/cm2. CT scan showed the posterior vertebral wall intact in all patients, and MRI displayed low signal on T1WI and high signal on T2WI of the vertebral fractures. Results All patients experienced dramatic pain relief after the procedures. The mean pain score (VAS) decreased significantly from 8.3 preoperatively to 2.1 after operation. The mean vertebral body height restoration was 54.2%?34.1% on the anterior border, 60.5%?35.4% in the middle portion, and 40.7%?32.3% on the posterior border respectively. And the sagittal alignment was improved significantly, as the average correction of the Cobb's angle reached 9.5?. No cement leakage was found on X-ray, except one with less cement at the anterior vertebral edge, but no clinical symptom occurred. All the patients were available at the final follow-up, the mean period was 10.5 months (range, 2-48 months). Conclusion Bilateral transpedicular kyphoplasty with single balloon not only can provide effective pain relief and vertebral height restoration, but also can improve the sagittal alignment significantly. Its clinical outcome was satisfactory.