The effect of latency on bone lengthening force and bone mineralization: an investigation using strain gauge mounted on internal distractor device

BACKGROUND: The purpose of this study was to investigate the effect of latency on the development of bone lengthening force and bone mineralization during mandible distraction osteogenesis. METHODS: Distraction tensions were investigated at different latency period in 36 rabbits using internal unilateral distractor. Strain gauges were prepared and attached to the distractor to directly assess the level of distraction tension during mandible lengthening. The tensile force environment of the mandible of rabbit during distraction was evaluated through in vivo experiments using two gauges. The animals were divided into 3 groups each containing 12 rabbits. Latency periods of 0, 4 and 7 days respectively were observed prior to beginning distraction. The distraction protocol consisted of a lengthening rate of 1 mm once daily for 8 days, followed by a consolidation phase of 2 weeks after which the animals were killed. Biopsies specimens were taken from the distracted area at the end of the distraction period. A non-distracted area of the mandible bone served as control. The specimens were analyzed by scanning electron microscopy to assess the ultrastructural pattern, and the bone mineralization. RESULTS: The resting tension acting on the distraction gap increases through distraction. The 7-day latency groups exhibit higher tension then those of 0-day and 4-days latency groups. Quantitative energy dispersive spectral analysis confirmed that immediate distractions were associated with lower calcium and phosphate atomic weight ratio. CONCLUSION: the latency periods could affect the bone lengthening tension and the bone mineralization process

CONNECT for quality: protocol of a cluster randomized controlled trial to improve fall prevention in nursing homes

<p>Abstract</p> <p>Background</p> <p>Quality improvement (QI) programs focused on mastery of content by individual staff members are the current standard to improve resident outcomes in nursing homes. However, complexity science suggests that learning is a social process that occurs within the context of relationships and interactions among individuals. Thus, QI programs will not result in optimal changes in staff behavior unless the context for social learning is present. Accordingly, we developed CONNECT, an intervention to foster systematic use of management practices, which we propose will enhance effectiveness of a nursing home Falls QI program by strengthening the staff-to-staff interactions necessary for clinical problem-solving about complex problems such as falls. The study aims are to compare the impact of the CONNECT intervention, plus a falls reduction QI intervention (CONNECT + FALLS), to the falls reduction QI intervention alone (FALLS), on fall-related process measures, fall rates, and staff interaction measures.</p> <p>Methods/design</p> <p>Sixteen nursing homes will be randomized to one of two study arms, CONNECT + FALLS or FALLS alone. Subjects (staff and residents) are clustered within nursing homes because the intervention addresses social processes and thus must be delivered within the social context, rather than to individuals. Nursing homes randomized to CONNECT + FALLS will receive three months of CONNECT first, followed by three months of FALLS. Nursing homes randomized to FALLS alone receive three months of FALLs QI and are offered CONNECT after data collection is completed. Complexity science measures, which reflect staff perceptions of communication, safety climate, and care quality, will be collected from staff at baseline, three months after, and six months after baseline to evaluate immediate and sustained impacts. FALLS measures including quality indicators (process measures) and fall rates will be collected for the six months prior to baseline and the six months after the end of the intervention. Analysis will use a three-level mixed model.</p> <p>Discussion</p> <p>By focusing on improving local interactions, CONNECT is expected to maximize staff's ability to implement content learned in a falls QI program and integrate it into knowledge and action. Our previous pilot work shows that CONNECT is feasible, acceptable and appropriate.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00636675">NCT00636675</a></p

Cell proliferation as assessed by expression of proliferating cell nuclear antigen or the uptake of bromodeoxyuridine in a rabbit model of leg-lengthening

Cell proliferation was assessed in an experimental system of leg-lengthening by two separate methods. The presence of proliferating cell nuclear antigen or the uptake of bromodeoxyuridine were determined immunohistochemically. Both methods indicated cell proliferation during leg-lengthening reaches a maximum at a distraction rate of 0.7 mm/day

Cell proliferation as assessed by expression of proliferating cell nuclear antigen or the uptake of bromodeoxyuridine in a rabbit model of leg-lengthening

Cell proliferation was assessed in an experimental system of leg-lengthening by two separate methods. The presence of proliferating cell nuclear antigen or the uptake of bromodeoxyuridine were determined immunohistochemically. Both methods indicated cell proliferation during leg-lengthening reaches a maximum at a distraction rate of 0.7 mm/day

The effect of interleukin-1β, tumour necrosis factor α and particle phagocytosis on monocyte-osteoclast differentiation

Interleukin-1 (IL-1) and tumour necrosis factor (TNF) are inflammatory cytokines which are known to influence osteoclastic bone resorption. To determine the effect of these cytokines on inflammatory macrophage-osteoclast differentiation, we added IL-1β and TNFα to long term co-cultures of mouse monocytes and osteoblastic cells. IL-1β (10 and 100 pg/ml) stimulated osteoclast formation as measured by expression of TRAP and the extent of lacunar bone resorption whereas TNFα (10 and 100 ng/ml) inhibited macrophage-osteoclast differentiation and bone resorption. Particle phagocytosis (which is known to stimulate the release of these cytokines) did not influence the extent of osteoclast formation. IL-1β stimulation of osteoclast formation may in part account for the increase in bone resorption associated with this inflammatory cytokine; TNFα inhibition of osteoclast formation may be due to interruption of the interaction between osteoblasts and osteoclast precursors