Tag: Poster 83

Center of Mass Displacement with a Rigid Ankle-Foot Orthotic in Healthy Individuals

Presenter: Spencer Smith

Co-Presenters: Therese Wichmann, Shannon Pomeroy, Michael Hahn,

Faculty Mentor: Shannon Pomeroy, Michael Hahn

Presentation Type: Poster 83

Primary Research Area: Science

Major: Human Physiology

Ankle arthritis is inflammation of the articular cartilage, resulting in pain, stiffness and diminished quality of life. Ankle arthritis is often treated with a complete artificial fusion of the affected bones and removal of the damaged cartilage, which can lead to significantly altered gait and further long-term complications. Rigid ankle-foot orthotics (AFOs) have been used in similar clinical populations to stabilize the joint; however, they have been shown to retain many gait characteristics and improve stability despite limiting ankle range of motion (ROM). In order to better understand how the body adapts to such a sudden and severe limitation of ankle ROM, we performed a gait analysis on 16 healthy individuals within the lab. Each subject went through a normal baseline walking trial on the treadmill followed by a 30 minute walking trial in which they were equipped with a rigid AFO. We used motion capture cameras to collect the 3D motion of strategically placed reflective markers. Subsequently, whole-body marker position data was used to calculate and observe the subjects’ center of mass between walking without an AFO and with an AFO over time. Preliminary data analysis indicates that a rigid AFO may result in increased COM displacement with a range less than baseline following 30 minutes of AFO acclimation, suggesting that an AFO leads to return to more normal gait given an acclimation period.

Short Range Sonic Hedgehog Signaling Promotes Heterotypic Cell Interactions Underlying Branching Morphogenesis of the Zebrafish Fin Skeleton

Presenter(s): Joshua Braunstein – Biology

Faculty Mentor(s): Kryn Stankunas, Scott Stewart

Poster 83

Research Area: Developmental Biology

Funding: ESPRIT
IMB Summer Scholarship Award
Alden Award

Zebrafish remarkably regenerate severed fins, perfectly restoring their original size and branched skeletal pattern. Sonic hedgehog a (Shha)-expressing epidermal cells mediate ray branching during regeneration by guiding localization of the pre-osteoblasts (pObs) while migrating and splitting into two populations. However, mechanisms of shha induction, the splitting of shha+ epidermal cells, and the mechanisms underlying epidermal to pObs interactions remain unresolved. Towards answering these questions, we explored if Hh/Smo signaling and epidermal dynamics also underlie developmental ray branching. We found that shha is expressed initially in basal epidermal cells along the entire length of forming fin bones in juvenile fish. As bones progressively mature, shha becomes distally restricted to epidermal cells neighboring Runx2+ pObs. We used TgBAC(ptch2:Kaede) fish and photoconversion to show Hh/Smo signaling is restricted to these pObs and immediately adjacent epidermal cells. shha+ epidermal cells split into two groups immediately preceding ray branching. By live imaging, we found these basal epidermal cells migrate distally over the pObs, cease Hh/Smo signaling, and are then shed. Small molecule inhibition of Hh/Smo using BMS-833923 increased epidermal migration speed, suggesting Hh/Smo signaling typically restricts the rate of migration by adhering epidermal cells to the pObs. Additional small molecule trials show the pathway is largely dedicated to ray branching during fin development. We conclude that instructive shha+ epidermal movements and Shh/Smo-promoted adhesion between epidermal cells and pObs direct branching morphogenesis to pattern the fin skeleton during both development and regeneration.

Importance of Grand Collection to undergraduate research

Presenter(s): Kate Jones

Faculty Mentor(s): Frances White & Alexana Hickmott

Poster 83

Session: Social Sciences & Humanities

Natural history collections allow researchers to answer questions using the large amount of data available from specimens housed in those collections. Bones or osteological specimens allow for investigations of the shape, function and movement of a particular species. With good information or provenance about the lives each specimen, detailed investigations can be undertaken. Collections, such as the Grand Collection housed in the University of Oregon Primate Osteology Lab, offer researchers the ability to study remains of primates after death. The Grand Collection was moved in 2010 and has over 300 specimens allowing for investigations covering a wealth of topics, including the morphology of primate hands and cranial symmetry, all of which were conducted primarily by undergraduate researchers. From the provenance information about each specimens before death, variables of the specimen’s life may be attached to information present in the bones. The natural and biological history collection found in the Grand Collection gives students the opportunity to learn aspects of curatorial maintenance and to prepare, clean, sort, identify, catalogue and measure specimens in the Grand Collection. These opportunities provide students with hands-on experiences in a biological laboratory and skills relevant to collection management, bone identification, and zoological educational experiences, which is invaluable in future scientific and biological pursuits. Overall, osteology laboratories create a safe and research-geared environment for researchers investigating a variety of questions.