Tag: Poster 19

Gait Performance While Performing Cognitive Tasks Continuously in Concussed High School Athletes

Presenter: Michael Kado

Mentor: Li-Shan Chou

AM Poster Presentation

Poster 19

Approximately 136,000 sports related concussions or mild traumatic brain injuries occur in the high school population annually. This study aims to further understand the initial deficits exhibited in the first 72 hours post injury. We hypothesized that the concussed individuals would walk with slower gait velocities and produce slower reaction times when compared to the control subjects during static and dynamic continuous Stroop testing. Motion data was collected using 29 reflective markers and a 10-camera motion analysis setup. The auditory Stroop task consisted of a computer that presented the word, high or low either in high or low pitch. The subject was then asked to declare which pitch the word was presented in, while ignoring the actual word announced. Each trial was present- ed in increments of four continuous presentations. For concussed subjects significant differences were detected in the gait velocity between level walking and walking while performing concurrent auditory Stroop tasks. This may be due to injury to a region of the brain that is susceptible to injury within 72 hours post concussion. We observed that tests that include divided attention and walking may give an indication of cognitive disturbances experienced post concussion. In the future this finding may be used to assist clinicians with the diagnosis of concussion.

Prevention of Ischemic Vascular Injury: Targeting Cellular Stress in the Endothelium with 5-aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR)

Presenter: Sarah Johnson

Mentor: Chris Minson

Poster: 19

Major: Biology

Ischemic-reperfusion (I/R) injury is a common complication in which tissues reperfused after an ischemic period experience further damage and dysfunction. Activation of endothelial cells (EC) produces excessive oxygen radicals and triggers vascular inflammation, cellular stress and apoptotic activation, which contribute to the pathophysiology of I/R injury. AMP-activated protein kinase (AMPK) stimulation has been shown to reduce I/R injury following coronary ligation, though the mechanism and cell specificity are unclear. Therefore, we hypothesize AICAR, an adenosine mimetic previously shown to activate AMPK, will promote cytoprotective pathways in ECs, reduce stress and attenuate apoptotic activity under hypoxic stress. To model ischemia, human umbilical vascular endothelial cells (HUVECs) were cultured at physiological normoxic or hypoxic (8 / 1% O2) conditions and treated with AICAR (0.2, and 2mM). Cell protein and media were collected for further analysis. AICAR increased (p<0.05) pAMPKα/AMPKα in hypoxic conditions, but not in normoxia. AICAR pretreatment (2mM, 1hr) and subsequent exposure hypoxia (24hr) showed decreased (p<0.05) BiP expression and cell-adhesion molecule ICAM-1 compared to normoxic control. AICAR reduced (p<0.05) cellular metabolic activity measured by MTT assay in both 8% and 1% O2. Further, reduced ET-1 secretion (p<0.05) followed AICAR treatment (434 ±14 vs. *179 ±1pg/mL). Endothelial permeability increased (p<0.05) with AICAR at 12 (869%) and 24 hours (315%) compared to controls. These data suggest that through AMPK activation, 1 hour treatment with AICAR slows cellular metabolic activity which reduces cell stress and apoptotic activity, and could be a novel modality for prevention of I/R injury in various reperfusion models such as coronary, transplanted tissue models, and vascular disease. Further in vivo studies are needed to assess these promising in vitro results.

Determining Ancestral Affiliation of Unprovenienced Human Remains from the Island of Mustique, Grenadine Islands, Caribbean

Presenter: Taylor Dodrill

Mentors: Scott Fitzpatrick and Greg Nelson, Anthropology

Poster: 19

Majors: Biology and Anthropology

The dearth of laws protecting cultural heritage in many Caribbean small island nations, or the lack of resources to enforce such laws, has led to destruction of numerous sites due to the removal of remains that would otherwise provide important archaeological information to help establish cultural context and affinity. We present an analysis of unprovenienced human remains that were in storage on the private island of Mustique in the Grenadines, southern Caribbean, but that were reportedly taken by a local resident from the smaller nearby island of Petite Mustique for personal use and display. With permission from the Mustique Company, archaeologists brought the remains to the University of Oregon’s Island & Coastal Archaeology Laboratory for analysis. The goal was to determine the number of individuals present, their probable age, sex, pathologies, and possible ancestry, in order to assist in repatriation. Preliminary results suggest that the collection consists of 341 bones or bone fragments, representing four adult individuals. Initial age and sex estimates for the three more complete individuals indicate that two are middle-aged males and one an older female. Robust muscle insertions of one adult male may indicate strenuous activity
in life. Intermingling of cattle bone with the remains, dental wear patterns, and other skeletal indicators suggest that these individuals probably date to the historic period. Further analysis that is now underway, including 3D geometric morphometrics of the skulls, will attempt to identify ancestry in more detail so the remains can be properly repatriated.

Gendered Perceptions and Emotions of Intercourse and Trauma

Presenter: Adriane Knorr

Faculty Mentor: Erin McKenna

Presentation Type: Poster 19

Primary Research Area: Social Science

Major: Philosophy

By interweaving philosophy of the mind, the anatomical body as well as feministic theories given by Charlotte Perkins Gilman, we can see how perceptions and emotions relating to trauma and sex are often considered to differ along gender lines. Sex and trauma are very closely linked in the human brain regarding the emotional and physical ties that remain after the acts. This presentation is a combination of a literary review of Gilman’s work and a scientific study of whether or not emotions can be gendered due to social constructs and anatomy. Gilman’s argument shows how she believes that male brains have gotten the opportunity to grow physically as well as mentally over time. This has led to gendered primality of the emotions and perceptions from our everyday lives. The neurological studies suggest an argument that neurological differences between the sexes have been linked with greater impulsivity and aggression in males. According to this argument, men are able to build metaphorical webs within their lives that lack the plethora of emotions that women often tie to their worlds. This can have a possible hindering effect on women when they try to move on after traumatic events due to denser connections to emotions that come tied to their memories. These three arguments derive an answer to the gendered emotions and perceptions that are prevalent in trauma and sex. Combining male and female brain discrepancies with the differences in cognitive understanding of sex and trauma we can see that the perceptions and emotions are heavily gendered based on social constructs as well as the scientific understandings of male and female anatomy.

Mapping Interactions Of Single-Stranded (Ss) DNA With the Ss-DNA Binding Protein (Gp32) of the T4 DNA Replication Complex at Specific Nucleotide Residue Positions

Presenter(s): Anson Dang − Biochemistry

Faculty Mentor(s): Pete von Hippel

Poster 19

Research Area: Natural Science, Biochemistry

Funding: Dreyfus Undergraduate Mentorships

The single-stranded (ss)DNA binding protein (gp32) of bacteriophage T4 plays a central role in regulating the functions and integration of the helicase, polymerase and primase components of the T4 DNA replication system. To understand how gp32 interacts with itself and with the other regulatory proteins and sub-assemblies of the T4 replication complex, we must first understand the structural details of how this protein binds to ssDNA lattices, both as isolated monomer subunits and as cooperatively bound gp32 clusters. We have explored these issues by monitoring differences in the fluorescence and circular dichroism (CD) spectra of site-specifically positioned monomers and dimer-pairs of 2-aminopurine (2-AP) probes located at various ssDNA positions within the binding site. In its cooperatively bound form gp32 spans 7 nucleotide residues per protein subunit, and by mapping spectral changes on binding to ssDNA lattices that are exact multiples of 7 residues in length we have been able to characterize interactions at defined positions within the gp32 binding cleft. We have extended these studies using acrylamide quenching and permanganate foot-printing assays to monitor degrees of base exposure at various lattice positions. Our results show that gp32 binds randomly at low concentrations, and then shifts toward preferential binding at the 5’-ends of the lattice as cooperatively bound gp32 clusters form at higher gp32 concentrations. Bases located near the middle of a gp32 binding site display lower solvent accessibility than those near the ends of the site. These differences in base ‘shielding’ may reflect deeper burial of the middle bases within the electropositive binding cleft, while bases at the ends may be made more accessible by fluctuations of the C- and N-terminal regulatory sub-domains of the protein. Insights into gp32- ssDNA interactions involved in controlling the functions of the T4 DNA replication complex that result from these studies will be discussed.

Characterizing Early DNA Break Repair in C. Elegans

Presenter(s): Nicole Szczepanski

Faculty Mentor(s): Diana Libuda & Austin Harvey

Poster 19

Session: Sciences

Accurate chromosome segregation is critical for the formation of viable gametes by the specialized cell division of meiosis. During meiosis, programmed double strand DNA breaks (DSBs) are formed and repaired by recombination mechanisms to maintain genomic integrity and to promote proper chromosome segregation. In order to better understand early repair dynamics of DSBs, we intended to devise a strain via CRISPR with an early repair phenotype closer to wildtype phenotype for future live imaging experiments. In past experiments, endogenously tagged GFP::RAD-51 mutants were utilized, but strayed from the usual wildtype phenotype. RAD-51 is a conserved recombinase that indicates an early repair stage of DSBs and is required for all meiotic recombination events. Using immunofluorescence, DSBs display distinct early repair dynamics through differential RAD-51 foci, leading to the hypothesis that these distinct dynamics indicate different DSB repair outcomes. Using the C. elegans model, we found that endogenously tagged GFP::RAD-51 mutants did not show a more wildtype RAD-51 foci phenotype after inheriting two copies of wildtype RAD-51 compared to worms that did not inherit the duplication. We also found that there is a significant difference between RAD-51 foci in early pachytene and late pachytene, the former having larger volumes and stronger intensities, representing interhomolog repair outcomes. In addition, interhomolog crossover repair outcomes show smaller, dimmer foci than do noncrossover outcomes. This indicates differential DSB end-resectioning between different stages within meiosis and between different repair outcomes.