Previous studies of the direct actions of bisphosphonates on bone have mainly been limited to their effects on bone-resorbing osteoclasts and little is known about the direct effects of bisphosphonates on osteoblasts. Here we report the direct effects of alendronate on the proliferation and osteogenic differentiation of the MG-63 osteoblast-like cell line. Cell proliferation was determined with the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay, osteogenic differentiation was evaluated with an alkaline phosphatase bioassay and by analysis of gene expression by reverse transcription-polymerase chain reaction, and the extent of calcium deposition was measured using Alizarin Red S staining. Alendronate significantly increased cell numbers over control values, with the greatest effect at 10(-8) M. Alkaline phosphatase activity and gene expression of bone morphogenetic protein 2, type I collagen and osteocalcin were increased after alendronate treatment. Alendronate also stimulated calcium deposition. We conclude that alendronate, apart from inhibiting osteoclastic bone resorption, is also a promoter of osteoblast proliferation and maturation.

Sacral giant cell tumour of bone has an insidious onset and slow growth rate, making early diagnosis difficult. The tumour has a high recurrence rate and is often fatal. Magnetic resonance imaging and computed tomography (CT), including CT-guided fine-needle biopsy, are useful for early diagnosis. Although therapy for sacral giant cell tumour often involves surgical resection and reconstruction challenges, improvements in various treatment modalities, including arterial embolization and radiotherapy, have widened the effective treatment options. The current surgical and adjuvant treatment modalities available for the management of sacral giant cell tumour are systematically reviewed and a suggested treatment algorithm is provided. En bloc excision remains the surgical procedure of choice, with functional reconstruction important in cases where the lesion is high in the sacrum. The use of adjuvant radiotherapy and chemotherapy remains controversial and should be studied further. Determination of the optimum treatment for sacral giant cell tumour will require randomized controlled trials. Early diagnosis, complete surgical resection with tumour-free margins and comprehensive treatment are important for local tumour control and improved outcome.

Infection in orthopedic implant surgery is a serious complication and a major cause of implant failure. Upon implant insertion, a contest between microbial colonization and tissue integration of the implant surface ensues. This race for the surface determines the probability of tissue integration or infection, and the surface properties of the substrate have an important role to play in determining the outcome. A number of strategies have been developed for the modification of implant surfaces to promote bone cell (osteoblast) functions and inhibit bacterial adhesion and growth. In this article, a review is given of these surface modification strategies, in particular those which can achieve the dual aim of bacterial inhibition and simultaneous enhancement of osteoblast functions. Surfaces of these types can be expected to have excellent potential for orthopedic applications. (Int J Artif Organs 2008; 31: 777–85)

A novel heterojunctional structure of n-ZnO nanonails array/p(+)-GaN light-emitting diode was fabricated by Chemical Vapor Deposition method. A broad electroluminescence spectrum shows two peaks centered at 435 nm and 478 nm at room temperature, respectively. By comparing the photoluminescence and electroluminescence spectra, together with analyzing the energy band structure of heterojunction light emitting diode, it suggested that the electroluminescence peak located at 435 nm originates from Mg acceptor level of p(+)-GaN layer, whereas the electroluminescence peak located at 478 nm originates from the defects of n-ZnO nanonails array.