Long-term result of guided nerve regeneration with an inert microporous polytetrafluoroethylene conduit.

OBJECTIVE: To evaluate the long-term outcome of Polytetrafluoroethylene (PTFE) conduit in nerve repair and to provide more evidence in view of its potential application to achieve a satisfactory functional recovery in clinical settings. METHODS: Thirty-six Wistar rats had their right sciatic nerve transected and were repaired with either conventional microsuture technique (Control group, n=18) or a PTFE conduit with a gap of 5 mm left between the nerve stumps (PTFE group, n=18). At 6 and 9 months after the operation, electrophysiological assessment and measurement of gastrocnemius muscle weight were conducted and morphology of the regenerated nerves were studied with image analysis. RESULTS: At 6 months postoperatively, the nerve conduction velocity recovered to 60.86% and 54.36% (P<0.05), and the gastrocnemius muscle weight recovered to 50.89% and 46.11% (P>0.05) in the Control group and the PTFE group respectively. At 9 months postoperatively, the recovery rate was 65.99% and 58.79% for NCV (P>0.05), and 52.56% and 47.89% for gastrocnemius muscle weight (P>0.05) in the Control group and the PTFE group respectively. Regenerated nerve fibers in the PTFE group had a regular round shape with no fragmentation, wrinkling or splitting of the myelin sheath. Image analysis revealed that the ratio of the myelin area to the total fiber area was larger at 9 months than at 6 months in both groups (P<0.01). CONCLUSIONS: Microporous PTFE conduit may be an alternative for nerve repair allowing of guided nerve regeneration and functional recovery with no obvious adverse effect at long-term.

scFv-mediated delivery of truncated BID suppresses HER2-positive osteosarcoma growth and metastasis.

Osteosarcoma is the most common primary malignant bone tumor, with high rates of metastasis. Here, we examined the expression of human epidermal growth factor receptor-2 (HER-2) in osteosarcoma cell lines with different metastatic potential, finding that the expression was correlated with metastasis of implanted tumors. We then introduced an expression vector encoding the e23sFv-PEA II-Bid Delta1-60 gene, composed of a HER2-specific single-chain antibody fused with domain II of Pseudomonas exotoxin A (PEA) and the carboxy end of truncated active Bid. We demonstrated that the e23sFv-PEA II-Bid Delta1-60 molecule selectively recognized and killed HER2-overexpressing osteosarcoma cells in vitro. Subsequently, we introduced the e23sFv-PEA II-bid Delta1-60 gene into BALB/c athymic mice bearing HER2-positive osteosarcomas using i.m. injections of liposome-encapsulated vector. Expression of the e23sFv-PEA II-Bid Delta1-60 gene suppressed tumor growth, significantly prolonged animal survival and inhibited metastasis, thereby suggesting it may represent a competitive approach to treating HER2/neu-positive osteosarcoma.

Effects of bone cement particles on the function of pseudocapsule-derived fibroblasts.

BACKGROUND: Despite the wide clinical use of bone cement, little is known about cellular responses to the debris from this material. We thus investigated the effects of bone cement particles on the secretion of soluble osteotropic factors in prosthetic pseudomembrane-derived fibroblasts. METHODS: Bone cement particles were added to fibroblasts maintained in tissue culture. The secretions of soluble receptor activator for nuclear factor kappa B ligand and osteoprotegerin together with interleukin-6 and tumor necrosis factor-alpha were assessed by enzyme-linked immunosorbent assays. The fibroblasts were also co-cultured with osteoclast precursors in the presence and absence of particles, and we assessed osteoclast formation and bone resorption. RESULTS: The particles produced an increase in the secretion of soluble receptor activator for nuclear factor kappa B ligand, interleukin-6 and tumor necrosis factor-alpha, but not osteoprotegerin. At a concentration of 88 particles/cell, bone cement particles yielded a 2-fold increase (327 pg/mL) in soluble receptor activator for nuclear factor kappa B ligand secretion, a 5-fold (239 pg/mL) increase in interleukin-6 secretion and 4-fold (129 pg/mL) increase in tumor necrosis factor-alpha secretion. The particles also enhanced bone resorption in the co-culture group. Both the increase in soluble receptor activator for nuclear factor kappa B ligand secretion and the increase in bone resorption were inhibited by the addition of neutralizing antibodies to the proinflammatory cytokines. INTERPRETATION: Our findings show that bone cement particles are capable of stimulating the secretion of soluble receptor activator for nuclear factor kappa B ligand in pseudocapsule-derived fibroblasts by increasing the secretion of proinflammatory cytokines, and may also promote implant loosening.

[Biomechanical study on the composite of allogenic decalcified bone matrix gelatin and bone cement].

OBJECTIVE: To evaluate the biomechanical properties and structural characteristics of various composites of partially decalcified allogenic bone matrix gelatin and bone cement at different ratios. METHODS: According to Urist method, partially decalcified allogenic bone matrix gelatin was prepared and mixed with bone cement at different ratios of 0, 400, 500, and 600 mg/g. Then the comparisons of these composites were performed in microstructure, ultimate compression strength and ultimate bending strength properties. RESULTS: The electronic microscope showed that the bone particles and bone cement were distributed evenly in the composite, irregularly connecting by multiple points; with the increase of bone particles and decrease of bone cement in the composite, there were more and more natural crevices, varying from 100 microns to 400 microns in width, in the biomaterials. Of all the composites with the ratios of 0, 400, 500, and 600 mg/g, the measurements of ultimate compression strength were (71.7 +/- 2.0) MPa, (46.9 +/- 3.3) MPa, (39.8 +/- 4.1) MPa, and (32.2 +/- 3.4) MPa, respectively; and the measurements of ultimate bending strength were (65.0 +/- 3.4) MPa, (38.2 +/- 4.0) MPa, (33.1 +/- 4.3) MPa and (25.3 +/- 4.6) MPa, respectively. CONCLUSION: The composite of partially decalcified allogenic bone matrix gelatin and bone cement has a good biomechanical property and could be easily fabricated and re-shaped, which make it available to be used clinically as an idea bone graft biomaterial.