The effect of osteocyte-derived RANKL on bone graft remodeling: An in vivo experimental study.

OBJECTIVES Autologous bone is considered the gold standard for grafting, yet it suffers from a tendency to undergo resorption over time. While the exact mechanisms of this resorption remain elusive, osteocytes have been shown to play an important role in stimulating osteoclastic activity through their expression of receptor activator of NF-κB (RANK) ligand (RANKL). The aim of this study was to assess the function of osteocyte-derived RANKL in bone graft remodeling. MATERIALS AND METHODS In Tnfsf11fl/fl ;Dmp1-Cre mice without osteocyte-specific RANKL as well as in Dmp1-Cre control mice, 2.6 mm calvarial bone disks were harvested and transplanted into mice with matching genetic backgrounds either subcutaneously or subperiosteally, creating 4 groups in total. Histology and micro-computed tomography of the grafts and the donor regions were performed 28 days after grafting. RESULTS Histology revealed marked resorption of subcutaneous control Dmp1-Cre grafts and new bone formation around subperiosteal Dmp1-Cre grafts. In contrast, Tnfsf11fl/fl ;Dmp1-Cre grafts showed effectively neither signs of bone resorption nor formation. Quantitative micro-computed tomography revealed a significant difference in residual graft area between subcutaneous and subperiosteal Dmp1-Cre grafts (p < .01). This difference was not observed between subcutaneous and subperiosteal Tnfsf11fl/fl ;Dmp1-Cre grafts (p = .17). Residual graft volume (p = .08) and thickness (p = .13) did not differ significantly among the groups. Donor area regeneration was comparable between Tnfsf11fl/fl ;Dmp1-Cre and Dmp1-Cre mice and restricted to the defect margins. CONCLUSIONS The results suggest an active function of osteocyte-derived RANKL in bone graft remodeling

Improving CT image analysis of augmented bone with raman spectroscopy

In recent years, bone graft substitutes have been increasingly used in the medical field, for example, in order to promote new bone formation. Microcomputed tomography (-CT) is an image-guided technique used in medicine as well as in materials science, enabling the characterization of biomaterials with high spatial resolution. X-ray-based methods provide density information; however, the question how far conclusions on chemical structures can be inferred from any kind of CT information has not been intensively investigated yet. In the present study, a bone sample consisting of autogenous bone derived cells (ABCs) and bovine bone mineral (BBM) was investigated by -CT and Raman spectroscopic imaging, that is, by two nondestructive imaging methods. Thereby, the image data were compared by means of regression analysis and digital image processing methods. It could be found that 51.8% of the variance of gray level intensities, as a result of -CT, can be described by different Raman spectra of particular interest for bone composition studies by means of a multiple linear regression. With the better description of -CT images by the linear model, a better distinction of different bone components is possible. Therefore, the method shown can be applied to improve CT-image-based bone modeling in the future

Zależność pomiędzy metodami oceny jakości rozwoju a efektywnością i konkurencyjnością przedsiębiorstw rolnych i ich uczestnictwie w systemie rachunkowości rolnej

The quality development methods (QDM) are one tool to decrease the company loss and increase the company productivity and profit. The reducing the loss of the production system decrease the costs of the product, increase the output and in this way the profitability of the company will be higher. A new concept of the quality and productivity development methods could be a paradigm shift in the agriculture production system. It means that the automotive QDM as the TPS (Toyota Production System) can be extended to the agricultural production. The effect of the QDM appear in the accounting system and the annual report.W artykule przedstawiono możliwości zastosowania metod oceny jakości rozwoju jako narzędzia ograniczenia strat przedsiębiorstw rolnych i podniesienia ich zysków