Publications by authors named "Karyne N Rabey"

6 Publications

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Cortical and trabecular morphometric properties of the human calvarium.

Bone 2021 07 23;148:115931. Epub 2021 Mar 23.

The Biomedical Instrumentation Laboratory, Department of Mechanical Engineering, University of Alberta, Postal Address: 10-203 Donadeo Innovation Centre for Engineering, 9211-116 Street NW, Edmonton T6G 1H9, Alberta, Canada; Department of Mechanical Engineering, University of Alberta, Postal Address: 10-203 Donadeo Innovation Centre for Engineering, 9211-116 Street NW, Edmonton T6G 1H9, Alberta, Canada. Electronic address:

There is currently a gap in the literature that quantitatively describes the complex bone microarchitecture within the diploë (trabecular bone) and cortical layers of the human calvarium. The purpose of this study was to determine the morphometric properties of the diploë and cortical tables of the human calvarium in which key interacting factors of sex, location on the calvarium, and layers of the sandwich structure were considered. Micro-computed tomography (micro-CT) was utilized to capture images at 18 μm resolution of male (n = 26) and female (n = 24) embalmed calvarium specimens in the frontal and parietal regions (N = 50). All images were post-processed and analyzed using vendor bundled CT-Analyzer software to determine the morphometric properties of the diploë and cortical layers. A two-way mixed (repeated measures) analysis of variance (ANOVA) was used to determine diploë morphometric properties accounting for factors of sex and location. A three-way mixed ANOVA was performed to determine cortical morphometric properties accounting for factors of cortical layer (inner and outer table), sex, and location. The study revealed no two-way interaction effects between sex and location on the diploë morphometry except for fractal dimension. Trabecular thickness and separation in the diploë were significantly greater in the male specimens; however, females showed a greater number of trabeculae and fractal dimension on average. Parietal specimens revealed a greater porosity, trabecular separation, and deviation from an ideal plate structure, but a lesser number of trabeculae and connectivity compared to the frontal location. Additionally, the study observed a lower density and greater porosity in the inner cortical layer than the outer which may be due to clear distinctions between each layer's physiological environment. The study provides valuable insight into the quantitative morphometry of the calvarium in which finite element modelers of the skull can refer to when designing detailed heterogenous or subject-specific skull models to effectively predict injury. Furthermore, this study contributes towards the recent developments on physical surrogate models of the skull which require approximate measures of calvarium bone architecture in order to effectively fabricate a model and then accurately simulate a traumatic head impact event.
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http://dx.doi.org/10.1016/j.bone.2021.115931DOI Listing
July 2021

Conditioning Electrical Stimulation Accelerates Regeneration in Nerve Transfers.

Ann Neurol 2020 08 26;88(2):363-374. Epub 2020 Jun 26.

Department of Surgery, University of Alberta, Edmonton, Alberta, Canada.

Objective: Compared to the upper limb, lower limb distal nerve transfer (DNT) outcomes are poor, likely due to the longer length of regeneration required. DNT surgery to treat foot drop entails rerouting a tibial nerve branch to the denervated common fibular nerve stump to reinnervate the tibialis anterior muscle for ankle dorsiflexion. Conditioning electrical stimulation (CES) prior to nerve repair surgery accelerates nerve regeneration and promotes sensorimotor recovery. We hypothesize that CES prior to DNT will promote nerve regeneration to restore ankle dorsiflexion.

Methods: One week following common fibular nerve crush, CES was delivered to the tibial nerve in half the animals, and at 2 weeks, all animals received a DNT. To investigate the effects of CES on nerve regeneration, a series of kinetic, kinematic, skilled locomotion, electrophysiologic, and immunohistochemical outcomes were assessed. The effects of CES on the nerve were investigated.

Results: CES-treated animals had significantly accelerated nerve regeneration (p < 0.001), increased walking speed, and improved skilled locomotion. The injured limb had greater vertical peak forces, with improved duty factor, near-complete recovery of braking, propulsive forces, and dorsiflexion (p < 0.01). Reinnervation of the tibialis anterior muscle was confirmed with nerve conduction studies and immunohistochemical analysis of the neuromuscular junction. Immunohistochemistry demonstrated that CES does not induce Wallerian degeneration, nor does it cause macrophage infiltration of the distal tibial nerve.

Interpretation: Tibial nerve CES prior to DNT significantly improved functional recovery of the common fibular nerve and its muscle targets without inducing injury to the donor nerve. ANN NEUROL 2020;88:363-374.
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http://dx.doi.org/10.1002/ana.25796DOI Listing
August 2020

Characteristics of Vibration that Alter Cardiovascular Parameters in Mice.

J Am Assoc Lab Anim Sci 2015 Jul;54(4):372-7

The Division of Laboratory Animal Resources, Duke University, Durham, North Carolina, USA.

We hypothesized that short-term exposure of mice to vibration within a frequency range thought to be near the resonant frequency range of mouse tissue and at an acceleration of 0 to 1 m/s(2) would alter heart rate (HR) and mean arterial pressure (MAP). We used radiotelemetry to evaluate the cardiovascular response to vibration in C57BL/6 and CD1 male mice exposed to vertical vibration of various frequencies and accelerations. MAP was consistently increased above baseline values at an acceleration near 1 m/s(2) and a frequency of 90 Hz in both strains, and HR was increased also in C57BL/6 mice. In addition, MAP increased at 80 Hz in individual mice of both strains. When both strains were analyzed together, mean MAP and HR were increased at 90 Hz at 1 m/s(2), and HR was increased at 80 Hz at 1 m/s(2). No consistent change in MAP or HR occurred when mice were exposed to frequencies below 80 Hz or above 90 Hz. The increase in MAP and HR occurred only when the mice had conscious awareness of the vibration, given that these changes did not occur when anesthetized mice were exposed to vibration. Tested vibration acceleration levels lower than 0.75 m/s(2) did not increase MAP or HR at 80 or 90 Hz, suggesting that a relatively high level of vibration is necessary to increase these parameters. These data are important to establish the harmful frequencies and accelerations of environmental vibration that should be minimized or avoided in mouse facilities.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4521570PMC
July 2015

Vibrating Frequency Thresholds in Mice and Rats: Implications for the Effects of Vibrations on Animal Health.

Ann Biomed Eng 2015 Aug 23;43(8):1957-64. Epub 2014 Dec 23.

Department of Evolutionary Anthropology, Duke University, Durham, NC, USA,

Vibrations in research facilities can cause complex animal behavioral and physiological responses that can affect animal health and research outcomes. The goal of this study was to determine the range of frequency values, where animals are unable to attenuate vibrations, and therefore may be most susceptible to their effects. Anesthetized and euthanized adult rats and mice were exposed to vibration frequencies over a wide range (0-600 Hz) and at a constant magnitude of 0.3 m/s(2). Euthanized animals were additionally exposed to vibrations at an acceleration of 1 m/s(2). The data showed that at most frequencies rodents were able to attenuate vibration magnitudes, with values for the back-mounted accelerometer being substantially less than that of the table. At frequencies of 41-60 Hz mice did not attenuate vibration magnitude, but instead the magnitude of the table and animal were equal or amplified. Rats experienced the same pattern of non-attenuation between 31 and 50 Hz. Once euthanized, the mice vibrated at a slightly more elevated frequency (up to 100 Hz). Based on these results, it may be prudent that in laboratory settings, vibrations in the ranges reported here should be accounted for as possible contributors to animal stress and/or biomechanical changes.
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http://dx.doi.org/10.1007/s10439-014-1226-yDOI Listing
August 2015

Locomotor activity influences muscle architecture and bone growth but not muscle attachment site morphology.

J Hum Evol 2015 Jan 15;78:91-102. Epub 2014 Nov 15.

Center for the Advanced Study of Hominid Paleobiology, Department of Anthropology, The George Washington University, 2114 G Street NW, Washington, DC 20052, USA. Electronic address:

The ability to make behavioural inferences from skeletal remains is critical to understanding the lifestyles and activities of past human populations and extinct animals. Muscle attachment site (enthesis) morphology has long been assumed to reflect muscle strength and activity during life, but little experimental evidence exists to directly link activity patterns with muscle development and the morphology of their attachments to the skeleton. We used a mouse model to experimentally test how the level and type of activity influences forelimb muscle architecture of spinodeltoideus, acromiodeltoideus, and superficial pectoralis, bone growth rate and gross morphology of their insertion sites. Over an 11-week period, we collected data on activity levels in one control group and two experimental activity groups (running, climbing) of female wild-type mice. Our results show that both activity type and level increased bone growth rates influenced muscle architecture, including differences in potential muscular excursion (fibre length) and potential force production (physiological cross-sectional area). However, despite significant influences on muscle architecture and bone development, activity had no observable effect on enthesis morphology. These results suggest that the gross morphology of entheses is less reliable than internal bone structure for making inferences about an individual's past behaviour.
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http://dx.doi.org/10.1016/j.jhevol.2014.10.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4278956PMC
January 2015

Life-long caloric restriction does not alter the severity of age-related osteoarthritis.

Age (Dordr) 2014 1;36(4):9669. Epub 2014 Jul 1.

Department of Orthopaedic Surgery, Duke University Medical Center, 375 Medical Sciences Research Bldg, 3093, Durham, NC, 27710, USA.

Chronic adipose tissue inflammation and its associated adipokines have been linked to the development of osteoarthritis (OA). It has been shown that caloric restriction may decrease body mass index and adiposity. The objectives of this study were to investigate the effect of lifelong caloric restriction on bone morphology, joint inflammation, and spontaneously occurring OA development in aged mice. C57BL/NIA mice were fed either a calorie-restricted (CR) or ad libitum (AL) diet starting at 14 weeks of age. All mice were sacrificed at 24 months of age. Adipose tissue and knee joints were then harvested. Bone parameters of the joints were analyzed by micro-CT. OA and joint synovitis were determined using histology and semiquantitative analysis. Lifelong caloric restriction did not alter the severity of OA development in C57BL/NIA aged mice, and there was no difference in the total joint Mankin score between CR and AL groups (p = 0.99). Mice also exhibited similar levels of synovitis (p = 0.54). The bone mineral density of the femur and the tibia was comparable between the groups with a small increase in cancellous bone volume fraction in the lateral femoral condyle of the CR group compared with the AL group. Lifelong caloric restriction did not alter the incidence of OA or joint synovitis in C57BL/NIA mice, indicating that a reduction of caloric intake alone was not sufficient to prevent spontaneous age-related OA. Nonetheless, early initiation of CR continued throughout a life span did not negatively impact bone structural properties.
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http://dx.doi.org/10.1007/s11357-014-9669-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4150885PMC
March 2015