Effect of polymeric scaffolds on attachment and growth of bone marrow mesenchymal stem cells / 生物医学工程学杂志

To investigate the effect of three kinds of polymeric scaffolds on attachment, proliferation and differentiation of bone marrow mesenchymal stem cells, the cells were different polymeric scaffolds of PLA-PEG, PLA, PLGA, respectively. The proliferation of cell was evaluated by cell count; the attachment and morphology of BMSCs were observed by SEM; and differentiation was detected by alkaline phosphatase activity, fluorescence, and RT-PCR methods. Results showed that the cells in PLGA group spread better among BMSCs adhered to the three polymeric scaffolds. The activity of ALP was detected after 3 days culture in these three groups. There were no significant differences between PLA-PEG and PLGA groups, but the activity of ALP was higher than PLA group. The gene expressions of osteocalicin and collagen I were also observed in the early culture time. Calcium nodes formation in these polymeric scaffolds were detected. BMSC spreading first, then overlapping growth and secretion of matrix around the bottom and surface of scaffolds were observed through SEM. In summary, PLA-PEG and PLGA are better polymeric scaffolds for the bone tissue engineering, compared with PLA.

Polymerase chain reaction analysis of the clonality of Porphyromonas gingivalis and collagenase gene / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the genotypic characterization of Porphyromonas gingivalis (Pg) and the heterogeneity of a potential virulence factor-PrtC.</p><p><b>METHODS</b>Arbitrarily primed polymerase chain reaction (AP-PCR) was applied to 80 Pg strains isolated from 24 unrelated Chinese periodontitis patients. PCR reaction was used to detect a fragment of the collagenase gene (PrtC gene). To evaluate the sequence heterogeneity of the Pg PrtC genes, sequence analysis of four PrtC gene of clinical isolates was performed.</p><p><b>RESULTS</b>Random primer OPA-05 and OPA-17 distinguished 7 AP-PCR profiles (I through VII). The majority of the strains belonged to type VII which accounted for 25.8%. A 548bp fragment of PrtC gene was detected from 24 clinical strains. The PCR products were verified by the restriction endonucleases PstI and PvuI. Sequence analysis showed 4 PrtC genes were heterogeneous in their nucleotide composition and differed from reference strain Pg 53977.</p><p><b>CONCLUSIONS</b>The results demonstrated genetic diversity existed among these clinical strains isolated from Chinese periodontitis patients and the PrtC genes are heterogeneous in their nucleotide sequence.</p>