Micro-morphologic changes around biophysically-stimulated titanium implants in ovariectomized rats

<p>Abstract</p> <p>Background</p> <p>Osteoporosis may present a risk factor in achievement of osseointegration because of its impact on bone remodeling properties of skeletal phsiology. The purpose of this study was to evaluate micro-morphological changes in bone around titanium implants exposed to mechanical and electrical-energy in osteoporotic rats.</p> <p>Methods</p> <p>Fifteen 12-week old sprague-dowley rats were ovariectomized to develop osteoporosis. After 8 weeks of healing period, two titanium implants were bilaterally placed in the proximal metaphyses of tibia. The animals were randomly divided into a control group and biophysically-stimulated two test groups with five animals in each group. In the first test group, a pulsed electromagnetic field (PEMF) stimulation was administrated at a 0.2 mT 4 h/day, whereas the second group received low-magnitude high-frequency mechanical vibration (MECHVIB) at 50 Hz 14 min/day. Following completion of two week treatment period, all animals were sacrificed. Bone sites including implants were sectioned, removed <it>en bloc </it>and analyzed using a microCT unit. Relative bone volume and bone micro-structural parameters were evaluated for 144 μm wide peri-implant volume of interest (VOI).</p> <p>Results</p> <p>Mean relative bone volume in the peri-implant VOI around implants PEMF and MECHVIB was significantly higher than of those in control (<it>P </it>< .05). Differences in trabecular-thickness and -separation around implants in all groups were similar (<it>P </it>> .05) while the difference in trabecular-number among test and control groups was significant in all VOIs (<it>P </it>< .05).</p> <p>Conclusion</p> <p>Biophysical stimulation remarkably enhances bone volume around titanium implants placed in osteoporotic rats. Low-magnitude high-frequency MECHVIB is more effective than PEMF on bone healing in terms of relative bone volume.</p

Demographics of extra-articular calcaneal fractures: Including a review of the literature on treatment and outcome

Introduction: Extra-articular calcaneal fractures represent 25-40% of all calcaneal fractures and an even higher percentage of up to 60% is seen in children. A disproportionately small part of the literature on calcaneal fractures involves the extra-articular type. The aim of this study was to investigate the incidence of extra-articular calcaneal fractures in a Level 1 trauma centre, define the distribution of the various types of fractures and compare patient demographics between extra- and intra-articular calcaneal fractures. In addition the literature was reviewed for the most common types of extra-articular calcaneal fractures with regard to incidence, treatment and clinical outcome. Methods: The radiological records between 2003 and 2005 were reviewed for intra- and extra-articular calcaneal fractures. Patient gender-distribution and age were compared. A literature search was conducted for the treatment of extra-articular calcaneal fractures. Results: In this 3-year study period a total of 49 patients with 50 extra-articular calcaneal fractures and 91 patients with 101 intra-articular fractures were identified. The median age for the first group was 32.7 years, and for the second group 40.3 years; P = 0.04. Male predominance was significantly less pronounced for extra-articular (63%) compared with intra-articular fractures (79%; P = 0.04). Conclusion: One-third of all calcaneal fractures are extra-articular. Significant differences exist between the intra- and extra-articular groups, in terms of lower age and male-female ratio. The literature study shows inconsistencies in treatment options, but most extra-articular fractures are well manageable conservatively

Highly purified CD38+ and CD38- sub-clones derived from the same chronic lymphocytic leukemia patient have distinct gene expression signatures despite their monoclonal origin.

CD38 expression is an important prognostic marker in chronic lymphocytic leukemia (CLL) with high levels of CD38 associated with shorter overall survival. In this study, we used gene expression profiling and protein analysis of highly purified cell-sorted CD38(+) and CD38(-) chronic lymphocytic leukemia cells to elucidate a molecular basis for the association between CD38 expression and inferior clinical outcome. Paired CD38(+) and CD38(-) CLL cells derived from the same patient were shown to be monoclonal by V(H) gene sequencing but despite this, CD38(+) CLL cells possessed a distinct gene expression profile when compared with their CD38(-) sub-clones. Importantly, CD38(+) CLL cells relatively over expressed vascular endothelial growth factor (VEGF) and appeared to preferentially utilize an internal autocrine VEGF survival loop. Elevated VEGF expression was associated with increased expression of the anti-apoptotic protein Mcl-1. Inhibition of VEGF receptor signaling also resulted in a reduction in cell viability. In contrast, exogenous VEGF caused a significant increase in CD38(-) CLL cell viability and a marked induction of Mcl-1; both effects were less obvious in CD38(+) CLL cells. Taken together, our data provide a biological rationale for the poor prognosis of CD38(+) CLL and indicate that both VEGF and Mcl-1 may prove to be useful therapeutic targets