ABSTRACT Reduced bioavailability of estrogen increases skeletal fracture risk in postmenopausal women, but the mechanisms by which regulates bone mass are incompletely understood. Because signaling acts, part, through receptor alpha (ERα), mice with global deletion ERα (ERαKO) have been used to determine role biology. These animals, however, confounding systemic effects arising from other organs, such as increased and decreased insulin-like growth factor 1 (IGF-1) serum levels, may...

The evolution of scutes in thyreophoran dinosaurs, based on Scutellosaurus, Scelidosaurus, Stegosaurus, and several ankylosaurs, began with small rounded or ovoid structures that typically had slight, anteroposteriorly oriented keels. These were elaborated two general overlapping ways: they could flare laterally asymmetrically beneath the keels mark anteroposterior axis, be hypertrophied their distal growth to produce plates, spikes, other kinds ornamentation. Stegosaurus plates spikes are...

Mechanical loading can be used to increase bone mass and thus attenuate pathological loss. Because the skeleton's adaptive response is most robust before adulthood, elucidating sex-specific responses during growth may help maximize peak mass. This study investigated effect of sex on controlled, in vivo mechanical growing mice. Ten-week-old male female C57Bl/6 mice underwent noninvasive compression left tibia. Peak loads −11.5 N were applied, corresponding +1,200 με at tibial midshaft both...

The skeleton's osteogenic response to mechanical loading can be affected by duration and rest insertion during a series of events. Prior animal studies have shown that the cortical bone saturates quickly short insertions between load cycles enhance formation. However, it remains unknown how affect load-induced osteogenesis in mouse tibial compressive model, particularly cancellous bone. To address this issue, we applied cyclic (-9 N peak load; 4 Hz) tibiae three groups 16 week-old female...

Estrogen receptor alpha (ERα) has been implicated in bone's response to mechanical loading both males and females. ERα osteoblast lineage cells is important for determining bone mass, but results depend on animal sex the cellular stage at which deleted. We demonstrated previously that when deleted from mature osteoblasts osteocytes mixed-background female mice, mass strength are decreased. However, few studies exist examining skeletal cell-specific ERαKO mice. Therefore, we crossed floxed...

Abstract The vertebrate skeleton is an adaptive structure that responds to mechanical stimuli by increasing bone mass under increased loads. Although experimental animal models have shown the anabolic cortical response applied load decreases with age, no consensus exists regarding whether this mechanism affected age in cancellous bone, tissue most impacted age-related loss. We used established murine vivo tibial loading model characterize load-induced cancellous, cortical, and whole...

As tetrapods increase in size and weight through ontogeny, the limb skeleton must grow to accommodate increases body resulting locomotor forces placed upon limbs. No study date, however, has examined how morphological changes during growth reflect ontogenetic patterns of loading stresses strains produced The goal this was relate forelimb loads vivo bone radius domestic goat (Capra hircus) across a range gaits speeds ontogeny while observing mechanics limb. In were recorded from two groups...

Visualizing the three-dimensional morphology and spatial patterning of cells embedded deep within dense connective tissues musculoskeletal system has been possible only by utilizing destructive techniques. Here we utilize fructose-based clearing solutions to image cell connectivity tissue-scale in situ standard confocal microscopy. Optical takes advantage refractive index matching tissue embedding medium visualize light transmission through a broad range bovine whole mount murine tissues,...

This study describes the mechanical role that cranial sutures play in fish during feeding. The long-term goal of our work is to establish relationships between suture form and function, so functional inferences can be made from morphology fossil taxa. To this end, strain gauges were surgically implanted across selected skull roof four individuals Polypterus endlicherii. After surgery, bone strains feeding recorded along with high-speed video events. Each trial was designated as a suction or...

Cardiac fibrosis is a disease state characterized by excessive collagenous matrix accumulation within the myocardium that can lead to ventricular dilation and systolic failure. Current treatment options are severely lacking due in part poor understanding of complexity molecular pathways involved cardiac fibrosis. To close this gap, vitro model systems recapitulate defining features fibrotic cellular environment need. Type I collagen, major extracellular protein component depositions, an...

ABSTRACT Strain magnitude has a controlling influence on bone adaptive response. However, questions remain as to how and if cancellous cortical tissues respond differently varied strain magnitudes, particularly at molecular level. The goal of this study was characterize the time‐dependent gene expression, formation, structural response female C57Bl/6 mice mechanical loading by applying varying load levels (low: −3.5 N; medium: −5.2 high: −7 N) skeleton using mouse tibia model. experiment...

Abstract Vertebrate long bone form, at both the gross and microstructural level, is result of many interrelated influences. One factor that considered to have a significant effect on form mechanical environment experienced by during growth. The work presented here examines possible relationships between in vivo strains, geometry histomorphology radii three age/size groups domestic goats. In strain data were collected from galloping goats, regional cortical distribution peak axial magnitudes,...

Evaluate performance and resistance to gap formation of a non-absorbable, barbed, monofilament suture, in comparison with smooth, polypropylene two different suture patterns: three-loop pulley (3LP) modified Bunnell-Mayer (BM). Seventy-two medium-sized cadaveric superficial digital flexor muscle tendon units. After manual transection repair, individual specimens were placed an electromechanical tensile testing machine tested monotonic failure using ramp loading. Video data acquisition...

Hypotheses suggest that structural integrity of vertebrate bones is maintained by controlling bone strain magnitude via adaptive modelling in response to mechanical stimuli. Increased tissue-level and rate have both been identified as potent stimuli leading increased formation. Mechanotransduction models hypothesize osteocytes sense deformation detecting fluid flow-induced drag the bone's lacunar–canalicular porosity. This model suggests osteocyte's intracellular depends on fluid-flow rate,...

The purpose of this study was to investigate the effects non-steady locomotor activities on load predictability in two goat forelimb bones and explore degree which bone curvature influences predictability. We measured vivo strains radius metacarpus juvenile goats performing a variety natural behaviors an outdoor arena compared these strain magnitudes loading patterns with those during steady-state treadmill locomotion. sought test hypotheses: our first hypothesis expects increase variability...