Matthew Silva

..We conclude that mechanical loading of the tibia is anabolic for cortical bone in young and middle-aged female BALB/c mice...

....

..002). We conclude that woven bone "repair" of a bone damaged by fatigue loading restores whole-bone strength and enhances resistance to further damage by repetitive loading...

..Within this article, I will review data on age-related changes in factors that affect fracture risk. Advanced engineering concepts will not be presented, but a familiarity with basic mechanical principles is assumed...

....

..Diabetic bone has greatly increased nonenzymatic collagen cross-links but only modestly reduced material properties. The loss of whole bone strength under both monotonic and fatigue loading is attributed mainly to reduced bone size...

..This marrow/endocortical defect did not affect the periosteum, where SAMP6 mice had normal to enhanced bone formation...

..In conclusion, FEA, with supporting strain gauge measurements, has provided unique insight regarding the strain environment throughout the tibia during three-point bending in mice...

..If the results of our animal study extend to healing of the human FDP insertion, they indicate that FDP tendons should be reattached to the distal phalanx by suture to the cortical surface rather than suture in a bone tunnel...

..The matrix weakness is attributed primarily to poorer organization of collagen fibers and reduced collagen content...

..Daily exposure to low-magnitude WBV by itself did not improve skeletal properties and did not enhance the PTH effect. No WBV-PTH synergy was found in this preclinical study...

..This finding highlights a limitation of the SAMP6 mouse as a model of senile osteoporosis...

..In conclusion, CHF 4227.01 exhibits a promising therapeutic and safety profile as a new SERM on both skeletal and extraskeletal outcomes...

..The angiogenic-osteogenic response is spatially coordinated and scaled to the level of the mechanical stimulus...

..This bone loss may impact healing by impeding the restoration of a strong tendon-bone interface...

..Future advances will probably require manipulation of the biological factors that promote healing...

..CONCLUSION: These findings suggest that at 6 weeks after surgery the intact tendon-bone repair site shows minimal histologic and molecular similarity when compared with unoperated specimens...

..To compare the initial biomechanical properties of zone I flexor tendon to bone repairs performed using pull-out and anchor techniques and to investigate the effect of bone quality and suture materials on the strength of anchor repairs...

....

..In this review, we describe recent efforts to enhance the integrity of the immature repair site. We focus on 2 major areas of advancement: surgical technique modifications and manipulation of the biologic and biochemical environment...

..We conclude that bones from aging female and male BALB/c mice exhibit many of the changes seen in humans and are therefore a clinically relevant model for studies of skeletal aging...

..Taken together, these results indicate that deficiency of Cx43 in osteoblasts attenuates but does not abolish anabolic responses to mechanical strain...

..We conclude that direct vibrational loading of bone in anesthetized, adult mice is not anabolic...

..05). In summary, 5 weeks of daily exposure to low-amplitude WBV had no skeletal effects in aged male mice. The potential of WBV to enhance bone mass in age-related osteoporosis is not supported in this preclinical study...

..In the future, the fatigue loading approach can be used create non-displaced bone fractures in transgenic and knockout mice to study the mechanisms by which the skeleton rapidly repairs damage...

..Thus, SHIP negatively regulates osteoclast formation and function and the absence of this enzyme results in severe osteoporosis...

..The progressive tendon degeneration that was observed here may have detrimental effects on repair site tensile properties, increasing the potential for early failure...

..Both growth factors may be effective in enhancing tendon healing in vivo...

....

..Together, our findings suggest that MAGP1 is a regulator of bone remodeling, and its absence results in osteopenia associated with an increase in osteoclast number...

..The application of growth factors holds promise for improving the tendon-repair response and obviating failure in the initial three weeks...

....

....

..We conclude that bone damage created without dynamic strain triggers a woven bone response, and thus infer that the woven bone response reported after fatigue loading and in stress fractures is in large part a response to bone damage...

..Complete removal of load by proximal transection resulted in tendon-to-bone repairs with less range of motion and lower biomechanical properties compared to repairs in which the muscle-tendon-bone unit was left intact...

..In conclusion, PDGF-BB treatment consistently improved the functional but not the structural properties of sutured intrasynovial tendons through 42 days following repair...

..Therefore, we hypothesized that magnesium-based bone adhesive (MBA) will improve the tendon-to-bone biomechanical properties initially and in the early period after repair...

....

..These findings extend the previous descriptions of the SAMP6 mouse and identify key mechanical features that further validate its relevance as a unique and functionally relevant model of senile osteoporosis...

..While these findings may be limited to the particular repair method we used, they demonstrate a need for devising new treatment strategies to improve healing of flexor tendon insertion site injuries...

....

..We tested this hypothesis in vivo in a model of genetic deficiency of the Cx43 gene (Gja1)...

..05 by Tukey post hoc test). We conclude MME is important in the multifactorial cascade of knee MCL injury healing, showing significant differences in both the early inflammatory and in the matrix tissue synthesis phases...

..05). The 0.1 g and 1.0 g groups also had higher BV/TV than the 0.3 g loaded group. If this non-dose-dependent phenomenon is verified by future studies, it suggests that a range of magnitudes should be examined for each application of WBV...

..These initial short-term data demonstrate the potential for a clinical treatment that could enhance tendon-to-bone healing...

..We hypothesized that PDGF-BB administered in this manner would improve the sutured tendon's functional and structural properties 3 weeks after repair...

..To develop a method by which a single impact force of controlled magnitude and rate could be applied uniformly to an area on the posterior aspect of the medial femoral condyle of adult rabbits...

..This loading model will be useful for examining biological responses to a range of sub-fracture damage levels in future experiments...

..Repair sites remained unorganized histologically and biomechanically inferior in comparison to previously described uninjured insertion sites...

..If these improved time-zero tensile properties persist during the early stages of healing, they may help decrease the incidence of repair-site gap formation associated with the forces of early motion rehabilitation protocols...

..Our second hypothesis was that there would be a positive effect from the combination of PDGF-BB and bFGF...

..Sustained delivery of growth factors may be achieved using a novel fibrin-based delivery system. PDGF-BB delivery increased cell proliferation and matrix remodeling and thus may accelerate flexor tendon healing...

..These results underscore the significance of normal muscle function in the maintenance of bone mass...

..This leads to increased tendon size and enhanced resistance to suture pullout. These findings offer a scientific rationale supporting the clinical practice of surgical re-attachment within the first 3 weeks after injury...

..We conclude that short-term, low-strain vibration results in increased chemo-transport, yet does not stimulate an increase in mechano-responsive or osteogenic gene expression, and cortical bone formation in tibias of adult mice...

..However, our findings did not support a dose-dependent effect of cigarette exposure on the tensile mechanical properties of ligaments...

..Neither suture caliber nor repair technique had a notable effect on strain at 20-N force, suggesting that early gap formation at the tendon-bone repair site may occur regardless of technique...

....

..CLINICAL RELEVANCE: Sixteen-millimeter arrows are a possible alternative to suture for repair of central tears. Thirteen-millimeter arrows may be effective for central and peripheral tears. Ten-millimeter arrows should not be used...

....

..Clinical Relevance: Identification of the factors involved with increased healing may allow manipulation of the healing response in the clinical setting...

..This model will be used in future in vivo studies and will potentially become an important tool for understanding the response of bone to vibrational loading...

..Our results support the use of the LG/J-by-SM/J mouse intercross populations as models for normal, complex genetic variation in obesity, bone properties and their interrelationship...

..Periosteal woven bone formed in proportion to the level of bone damage, resulting in the rapid recovery of whole bone strength independent of stress fracture severity...

..These findings confirm that a single high-energy impact load can cause the development of PTA by disrupting the extracellular matrix and by causing a decrease in chondrocyte metabolism...

....

..In summary, our findings demonstrate the remarkable ability of the adult skeleton to rapidly form periosteal woven bone and thereby offset the negative structural effects of acute fatigue damage and subsequent intracortical resorption...

..CONCLUSION: Neither technique reproduced the biomechanical profile of the native ulnar collateral ligament; the findings of this study suggest that the docking construct may offer initial biomechanical advantage over the Jobe construct...

....

....

....

..abstract_text> ..

..The goal of this project is to understand the biological pathways that control bone formation following mechanical stimulation. This information may lead to future strategies to increase bone mass and reduce skeletal fragility. ..