Tag: Human Physiology

The Prevalence of Metabolic Syndrome Components and their Association with HbA1c in Tunisia

Presenter: Adriana Wisniewski – Human Physiology, Multidisciplinary Science

Faculty Mentor(s): Josh Snodgrass, Alicia DeLouize

Session: (In-Person) Oral Panel—Healthy Considerations

The prevalence of diabetes and other noncommunicable diseases (NCDs) is rapidly increasing worldwide. Metabolic syndrome (MetS) is characterized by a combination of metabolic components (e.g., abdominal obesity and elevated blood pressure) that are risk factors for NCDs such as cardiovascular disease, stroke, and type 2 diabetes. Anthropometric, biomarker, and sociodemographic data were collected from a nationally representative sample of individuals 15 years and older (n = 7444) as part of the Tunisian Health Examination Survey, a collaboration between the World Health Organization and the Tunisian Ministry of Health. Examining both diabetic and nondiabetic groups, we hypothesize that: 1) there will be positive associations between HbA1c levels and individual components of MetS, and 2) there will be positive associations between HbA1c levels and the cumulative number of MetS components. Results showed that both diabetic women and men had positive associations between HbA1c and triglyceride levels and between HbA1c and systolic blood pressure(SBP). Nondiabetic women and men had positive associations between HbA1c and LDL cholesterol levels and HbA1c and triglyceride levels. Nondiabetic men also had a negative association between HbA1c and HDL cholesterol levels. These findings highlight the different MetS components and metabolic risk factors that are associated with increasing HbA1c levels in Tunisian diabetic and nondiabetic populations.

Utilizing real time strain to modulate patient-specific rehabilitation optimizing bone recovery

Presenter: Alyssa Vongphachanh – Human Physiology

Co-Presenter(s): Walker Rosenthal

Faculty Mentor(s): Kylie Nash

Session: (In-Person) Poster Presentation

Severe bone injuries often result in high complication rates and poor functional recovery. Mechanical loading through rehabilitation is a longstanding treatment for these injuries, but current practices are still challenged with variable healing, limiting this promising therapeutic [1,2]. Recent advancements in implantable strain sensors may promote better understanding of how rehabilitation induced loads contribute to healing outcomes [1]. Our lab uses this idea in a rat femoral segmental model stabilized with an internal fixation plate embedded with an implantable strain sensor to analyze the mechanical environment throughout healing for different loading conditions. Past work has found that load-sharing (compliant) fixation devices exhibited improved healing outcomes when compared to load-shielding (non-compliant) fixation plates [3]. We investigated the effects of rehabilitation on bone volume by using a wireless compliant fixation device capable of acquiring real-time micro-strain measurements on a segmental defect in the femur. We found that bone union occurred in 3/3 rehabilitated rats and only 2/4 in non-rehabilitated, sedentary counterparts. Rehabilitated rats experienced a higher mean strain amplitude and their bones bridged earlier than their sedentary counterparts. Our findings suggest a relationship between strain and bone healing outcomes. We hope to further explore the effects of rehabilitation intensity on local defect strain and thus bone healing outcomes.

Optical Based Sensing of Shear Strain using Reflective Color Patterns

Presenter: Maryam Shuaib – Human Physiology

Faculty Mentor(s): Mike McGeehan, Keat Ghee Ong

Session: (In-Person) Oral Panel—Stimuli and Response, Poster Presentation

There is an increasing need to measure shear force in biomedical applications. Many shear force sensors exist, but are often impractical as they can be bulky, require large amounts of power, and are sensitive to electromagnetic interference. The goal of this project is to apply new optoelectronic sensing principles to measure shear strain. Optoelectronic sensors have various advantages including a smaller design that is able to measure multi-axial shear strain. This particular sensor functions through optical coupling of an LED that emits red, green, and blue (RGB) light, which is then reflected off of an adjacent surface displaying a color pattern consisting of randomized color pixels (Figure 1A). Shearing between these surfaces is measured using a photodiode, which senses changes in the RGB light intensities due to the shifts in the color pattern’s position. The purpose of this study was to compare the efficacy of various color patterns and classification algorithms to determine multi-axial shear strain. The optimal sensor configuration was found to be Pattern 3 (Figure 1B) with a Weighted K-Nearest-Neighbor algorithm with an accuracy of 98%, and a misclassification cost of 0.07 millimeters. The accuracy and robustness of the sensor-derived measurements, along with the practical and scalable design, support the use of this sensor in a multitude of biomedical applications.

Utilizing real time strain to modulate patient-specific rehabilitation optimizing bone recovery

Presenter(s): Walker Rosenthal – Human Physiology

Co-Presenter(s): Alyssa Vongphachanh

Faculty Mentor(s): Kylie Nash

Session: (In-Person) Poster Presentation

Severe bone injuries often result in high complication rates and poor functional recovery. Mechanical loading through rehabilitation is a longstanding treatment for these injuries, but current practices are still challenged with variable healing, limiting this promising therapeutic [1,2]. Recent advancements in implantable strain sensors may promote better understanding of how rehabilitation induced loads contribute to healing outcomes [1]. Our lab uses this idea in a rat femoral segmental model stabilized with an internal fixation plate embedded with an implantable strain sensor to analyze the mechanical environment throughout healing for different loading conditions. Past work has found that load-sharing (compliant) fixation devices exhibited improved healing outcomes when compared to load-shielding (non-compliant) fixation plates [3]. We investigated the effects of rehabilitation on bone volume by using a wireless compliant fixation device capable of acquiring real-time micro-strain measurements on a segmental defect in the femur. We found that bone union occurred in 3/3 rehabilitated rats and only 2/4 in non-rehabilitated, sedentary counterparts. Rehabilitated rats experienced a higher mean strain amplitude and their bones bridged earlier than their sedentary counterparts. Our findings suggest a relationship between strain and bone healing outcomes. We hope to further explore the effects of rehabilitation intensity on local defect strain and thus bone healing outcomes.

A Homeodomain Protein Generates Neuronal Diversity and Connectivity in the Drosophila Lamina

Presenter: Tyler Ramos – Human Physiology

Faculty Mentor(s): Chundi Xu

Session: (In-Person) Oral Panel—Daily Dose of Proteins

How we perceive and integrate our experiences is the result of an intricate network of diverse neuron types, each with specific connectivity. To generate different neurons, signals in precursors give each neuron its unique neuronal fate. Subsequently, a combination of proteins called homeodomain transcription factors (TFs) grant neurons proper synaptic connectivity. The processes of fate selection and synapse assembly are sequential actions that have been characterized separately but are deeply connected. It is unknown if a common regulator exists between these two developmental steps. Our purpose is to test if a homeodomain TF can function as a regulator of both neuronal fate and synaptic connectivity. To pursue this, we use the lamina neurons (L1-L5) of the fruit fly, Drosophila melanogaster. We show that homeodomain TF Brain-specific homeobox (Bsh) is expressed in lamina precursor cells, which suggests it may play a role in establishing lamina neuron fate. Using cell- specific knockdown and tracing methods, we found removing Bsh generates L1 and L3 neurons at the expense of L5 and L4 neurons, respectively. In L4 neurons, Bsh activates another protein, Apterous (Ap). Knockdown of Bsh and Ap in L4 neurons resulted in the loss of a synapse recognition molecule and altered synaptic connectivity. We propose that the homeodomain TF Bsh functions as a regulator of both neuronal fate and synaptic connectivity, which may be a conserved developmental mechanism across organisms.

Skeletal Muscle Compliance and Composition in Young Men and Women

Presenter: Ayooluwa Popoola – Human Physiology

Faculty Mentor(s): Austin Ricci, Damien Callahan

Session: (In-Person) Poster Presentation

Skeletal muscle is a complex tissue, comprised at the whole tissue level of contractile structures, adipose and connective tissue. The relationships between composition and biological sex are important because composition likely affects muscle contractile performance. However, the mechanisms through which composition and stiffness interdependently influence function between men and women remain largely unclear.

Purpose: to investigate the differences in active and passive stiffness of the vastus lateralis muscle (VL) and patellar tendon (PT) in young men and women.

Methods: We recruited 14 young healthy participants, 9 men and 5 women. Participants performed 3 maximum voluntary isometric contractions (MVIC) of the knee extensor muscles (KE) to determine peak torque. Passive stiffness was measured at the VL and PT using digital palpation (DP) prior to MVIC measurements. Active stiffness was measured at 25%, 50%, and 100% MVIC during ramped contractions using DP and ultrasound.

Results: Passive stiffness was not different between sexes at the PT or VL. Active stiffness was less in women at the VL [0.19] and PT [0.03]. Women had higher subcutaneous adipose thickness (SAT) [<0.001] and echogenicity [<0.001] with similar muscle thickness.

Conclusion: Data suggests muscle activation comparatively alters stiffness in women. Despite similar muscle thickness, women have higher SAT and echogenicity, two characteristics known to reduce stiffness.

Effect of Mild Hypohydration on Renal Hemodynamics during Exercise Pressor Reflex Activation

Presenter: Cameron O’Connell – Human Physiology

Faculty Mentor(s): Chris Chapman

Session: (In-Person) Poster Presentation

Sweating during passive heat stress can induce a state of low body water known as hypohydration. Mild hypohydration combined with elevated core body temperature attenuates increases in renal vasoconstriction during a sympathetic stimulus. It is unknown whether hypohydration, independent of heat stress, elicits a similar altered renal hemodynamic response. We tested the hypothesis that prolonged mild hypohydration attenuates reductions in renal artery blood velocity (RBV) during exercise pressor reflex activation compared to a hydrated state (i.e., euhydrated). Eight healthy adults (5 females) performed two trials following 24 hours of fluid deprivation (HYPO) or when euhydrated (EUHY). RBV was assessed using Doppler ultrasonography during two minutes of static handgrip exercise (Handgrip) that was immediately followed by two minutes of post-exercise arterial occlusion (Occlusion). The 24-hour protocol induced a mild hypohydration in HYPO, as noted by greater reductions in body mass (HYPO: -2.2±0.5%; EUHY: -0.3±0.7%, P=0.001). At the end of Handgrip, there was a trend toward attenuated reductions in RBV in HYPO compared to EUHY (HYPO: -1.6±4.8 cm·s-1; EUHY: -6.2±6.0 cm·s-1, P=0.16). At the end of Occlusion, RBV, was not different between conditions (P=0.52). These preliminary findings suggest that prolonged mild hypohydration may attenuate the renal hemodynamic response to the static handgrip phase of exercise pressor reflex activation.

Spatial Location and Memory Integration

Presenter: Dahlia Mohd Razif – Business Administration, Human Physiology, Neuroscience, Psychology

Faculty Mentor(s): Lea Frank, Dasa Zeithamova

Session: (In-Person) Poster Presentation

Memory is flexible and can be influenced by other items or events that we have encountered. Memory integration refers to the concept that related memories are stored in the brain as overlapping representations which form a memory link that allow us to make new inferences or extract related information. Studies have shown that memory integration is enhanced by time proximity when items or events occur within a close time frame but not much is known regarding how spatial positioning affects memory integration. 160 participants will be split into a spatial overlapping condition and a no spatial overlapping condition. This experiment consists of a study trial, an associative inference test and an associative memory test. During the study trial, participants will be presented with object images positioned relative to base object images. For the associative inference test and memory test, object images will be presented as cues to evaluate the extent that participants can integrate the associations that share the common element of the base object as well as remember presented pairs during the study trial. As the date of submission of this abstract is prior to data collection, conclusions have not been realized. We hypothesize that spatial overlapping of items will result in diminished memory integration due to interference. This research can help deepen our understanding of how the brain encodes separate items and creates an integrated representation of the shared information.

Content Overload And Its Effects On Learning

Presenter: Erika Moe – Human Physiology

Faculty Mentor(s): Sarah DuBrow, Lindsay Rait

Session: (In-Person) Poster Presentation

The asynchronous nature of remote classes brought by COVID-19 provides students greater control over their daily studies and has proven to be a double-edged sword. To better understand the effect of a growing asynchronous workload, subjects completed two scenarios: one with a condensed, structured workload (2-topic condition) and another with a larger workload (8-topic condition). It was hypothesized that increasing workload (creating a “content overload”) would be detrimental for all students. Furthermore, individuals who preferred remote learning would perform best with larger presented workloads. Individuals who preferred in-person learning would perform best with a structured, condensed presented workload. Subjects read passages on a variety of academic topics and were tested the next day in an SAT-like format. Additionally, pre- and post-test questionnaires were completed for correlations between learning preference and differences between conditions. Data analysis is ongoing. A paired t-test for within-subject analysis will compare the average test results of the 2-topic and 8-topic conditions. The results of this study will provide insight into how COVID online classes have affected the comprehension of the student population. With a better understanding of the content overload effect, educational workers will have the opportunity to better tailor their remote lesson plans for a diverse body of students with different attentional, memory, and cognitive abilities.

Electromyography Markers of Global Motor Inhibition While Stopping

Presenter: Isaiah Mills – Human Physiology

Faculty Mentor(s): Ian Greenhouse, Mitchell Fisher

Session: (In-Person) Poster Presentation

Stopping individual parts of complex movement plans is a critical part of controlling our bodies. While humans can coordinate movements effectively, our brains have limitations in selective stopping ability. Cancelling one action can affect other simultaneous actions, especially when these actions are bimanual. In one stopping task where participants had to cancel one finger movement while continuing a movement with the other hand, the executed lift was delayed from the target reaction time. This is thought to be caused by a neural pathway which nonselectively inhibits all actions before restarting continuing actions. Here, we record the activation of little finger muscles using electromyography during tonic muscle contraction. Subjects hold contraction as they perform a similar task involving timing bimanual index finger movements to a target time. During stop trials where one or both movements are inhibited we hypothesize that the amplitude of tonic EMG will decrease representing nonselective motor inhibition. Preliminary data analysis supports this hypothesis. This data will help us understand how healthy control of movement is facilitated by the brain, and during what period following a stop signal this network is actively suppressing movement. Patients who suffer from movement disorders like Parkinson’s struggle to control inhibitory processes, and we hope to learn more about the disease and how it affects these pathways by comparing healthy datasets to disease state.