Study of inducing bone marrow-derived mesenchymal stem cells into chondrocytes in vitro / 中国骨伤

<p><b>OBJECTIVE</b>To explore a method of isolation, culture and chondrogenic phenotype differentiation of mesenchymal stem cell (MSCs) from the bone marrow of rats in vitro and to offer experimental reference for the resources of seeding cells in cartilage tissue engineering.</p><p><b>METHODS</b>MSCs were isolated from bone marrow and purified by density gradient centrifuge and cultured in vitro. The MSC adherence formed and those in passage 3 were chosen to induce into chondrogenic differentiation. After 7, 14, 21 days, immunohistochemical techique was applied to detect the expression of collagen type II. The differentiated cells were implanted on the CPP/PLLA composites. After the cell-scaffold complex was cultured in vitro for one week, the ultrastructure of the scaffold was observed with scanning electron microscopy.</p><p><b>RESULTS</b>The differentiated cells changed from a spindle-like fibroblastic appearance to a polygonal shape, the capability of proliferation was down markedly. Immunohistochemical staining of collagen II were positive for the pass age, especially in the 21st days. Induced MSCs were well adherent to the scaffold composites and the cells were embedded by the cell-matrix.</p><p><b>CONCLUSION</b>Under the induced medium, MSCs can differentiate into chondrogenic phenotype and secrete specificity matrix of cartilage in vitro. MSCs can likely be served as optimal cell source for cartilage tissue engineering.</p>

Interactions between effects of estrogen receptor gene polymorphisms on BMD and experiences of the first spermorrhea in Chinese Han boys / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To study the interaction between polymorphisms of estrogen receptor (ER) gene and puberty on bone mineral density (BMD).</p><p><b>METHODS</b>One hundred and forty-six boys aged 13-17 years were divided into two groups according to their first spermorrhea. DNA was analyzed for Xba I and Pvu II genotypes by PCR-RFLP. BMD of the total body, forearm and lumbar spine was measured by dual-energy X-ray absorptiometry (DXA). The relationship between polymorphisms of ER gene and BMD in these two groups was analyzed.</p><p><b>RESULTS</b>The BMD at all sites in the spermorrhea group was significantly higher than that in the un-spermorrhea group. The independent contribution of ER genotypes to BMD at two pubertal stages was analyzed after adjusting co-variables. In the un-spermorrhea group, the BMD at distal 1/10 and 1/3 forearm of those carrying pp genotype was significantly higher than that of the non-carries, whereas in the spermorrhea group BMD in those carrying the same genotype was significantly lower than that in the non-carriers. Similar results were obtained by haplotype analysis. Multiple stepwise regression analysis showed that body weight, age and the first spermorrehea were the dominant determinants for BMD. BMD at forearm might be influenced by interaction between ER genotype and the first spermorrehea.</p><p><b>CONCLUSION</b>The polymorphisms of ER gene play a different role in BMD influenced by the first spermorrhea. Chinese boys carrying p or x allele should pay more attention to their bone mass.</p>