Life Sciences Commons^™

Single-Leg Cycling To Maintain And Improve Function In Healthy And Clinical Populations, C. Eric Heidorn, Steve Elmer, Kyle W. Wehmanen, James C. Martin, John Mcdaniel

Michigan Tech Publications

Exercise with reduced muscle mass facilitates greater muscle-specific adaptations than training with larger muscle mass. The smaller active muscle mass can demand a greater portion of cardiac output which allows muscle(s) to perform greater work and subsequently elicit robust physiological adaptations that improve health and fitness. One reduced active muscle mass exercise that can promote greater positive physiological adaptations is single-leg cycling (SLC). Specifically, SLC confines the cycling exercise to a smaller muscle mass resulting in greater limb specific blood flow (i.e., blood flow is no longer “shared” by both legs) which allows the individual to exercise at a greater …

Beyond The Baroreflex: A New Measure Of Autonomic Regulation Based On The Time-Frequency Assessment Of Variability, Phase Coherence And Couplings, Philip T. Clemson, Jeffrey B. Hoag, William H. Cooke, Dwain L. Eckberg, Aneta Stefanovska

Michigan Tech Publications

For decades the role of autonomic regulation and the baroreflex in the generation of the respiratory sinus arrhythmia (RSA) - modulation of heart rate by the frequency of breathing - has been under dispute. We hypothesized that by using autonomic blockers we can reveal which oscillations and their interactions are suppressed, elucidating their involvement in RSA as well as in cardiovascular regulation more generally. R-R intervals, end tidal CO2, finger arterial pressure, and muscle sympathetic nerve activity (MSNA) were measured simultaneously in 7 subjects during saline, atropine and propranolol infusion. The measurements were repeated during spontaneous and fixed-frequency breathing, and …

Control Of Orthodontic Tooth Movement By Nitric Oxide Releasing Nanoparticles In Sprague-Dawley Rats, Derrick Crawford, Tommy C. Lau, Megan C. Frost, Nan E. Hatch

Michigan Tech Publications

Orthodontic treatment commonly requires the need to prevent movement of some teeth while maximizing movement of other teeth. This study aimed to investigate the influence of locally injected nitric oxide (NO) releasing nanoparticles on orthodontic tooth movement in rats. Materials and Methods: Experimental tooth movement was achieved with nickel-titanium alloy springs ligated between the maxillary first molar and ipsilateral incisor. 2.2 mg/kg of silica nanoparticles containing S-nitrosothiol groups were injected into the mucosa just mesial to 1st molar teeth immediately prior to orthodontic appliance activation. NO release from nanoparticles was measured in vitro by chemiluminescence. Tooth movement was measured using …

Physiological Responses To Acute Cycling With Blood Flow Restriction, Matthew A. Kilgas, Tejin Yoon, John Mcdaniel, Kevin Phillips, Steve Elmer

Michigan Tech Publications

Aerobic exercise with blood flow restriction (BFR) can improve muscular function and aerobic capacity. However, the extent to which cuff pressure influences acute physiological responses to aerobic exercise with BFR is not well documented. We compared blood flow, tissue oxygenation, and neuromuscular responses to acute cycling with and without BFR. Ten participants completed four intermittent cycling (6 × 2 min) conditions: low-load cycling (LL), low-load cycling with BFR at 60% of limb occlusion pressure (BFR60), low-load cycling with BFR at 80% of limb occlusion pressure (BFR80), and high-load cycling (HL). Tissue oxygenation, cardiorespiratory, metabolic, and perceptual responses were assessed during …

Activation Of Orexin System Stimulates Camkii Expression, Yuanyuan Fan, Enshe Jiang, Huanjia Gao, Jeremy Bigalke, Bojun Chen, Chunxiu Yu, Qinghui Chen, Zhiying Shan

Michigan Tech Publications

Hyperactivity of the orexin system within the paraventricular nucleus (PVN) has been shown to contribute to increased sympathetic nerve activity (SNA) and blood pressure (BP) in rodent animals. However, the underlying molecular mechanisms remain unclear. Here, we test the hypothesis that orexin system activation stimulates calcium/calmodulin-dependent kinase II (CaMKII) expression and activation, and stimulation of CaMKII expressing PVN neurons increases SNA and BP. Real-time PCR and/or western blot were carried out to test the effect of orexin-A administration on CaMKII expression in the PVN of normal Sprague Dawley (SD) rats and orexin receptor 1 (OX1R) expressing PC12 cells. Immunostaining was …

Activation Of Orexin 1 Receptors In The Paraventricular Nucleus Contributes To The Development Of Deoxycorticosterone Acetate-Salt Hypertension Through Regulation Of Vasopressin, Jeremy Bigalke, Huanjia Gao, Qing Hui Chen, Zhiying Shan

Michigan Tech Publications

Salt-sensitivity is a major factor in the development of hypertension. The brain orexin system has been observed to play a role in numerous hypertensive animal models. However, orexin’s role in the pathology of salt-sensitive hypertension (SSH) remains to be adequately explored. We assessed the impact of orexin hyperactivity in the pathogenesis of the deoxycorticosterone acetate (DOCA) – salt rat model, specifically through modulation of Arginine Vasopressin (AVP). Adult male rats were separated into three groups: vehicle control, DOCA-salt, and DOCA-salt+OX1R-shRNA. DOCA-salt rats received subcutaneous implantation of a 21-day release, 75 mg DOCA pellet in addition to saline drinking water (1% …

Sex Differences In Self-Report Anxiety And Sleep Quality During Covid-19 Stay-At-Home Orders, Jeremy Bigalke, Ian Greenlund, Jason R. Carter

Michigan Tech Publications

Background: COVID-19 and home isolation has impacted quality of life, but the perceived impact on anxiety and sleep remains equivocal. The purpose of this study was to assess the impact of COVID-19 and stay-at-home orders on self-report anxiety and sleep quality, with a focus on sex differences. We hypothesized that the COVID-19 pandemic would be associated with increased anxiety and decreased sleep quality, with stronger associations in women. Methods: One hundred three participants (61 female, 38 ± 1 years) reported perceived changes in anxiety and sleep quality due to stay-at-home orders during the COVID-19 pandemic and were administered the Spielberger …

The Influence Of Thermal Alterations On Prefrontal Cortex Activation And Neuromuscular Function During A Fatiguing Task, Kevin Phillips, Derek Verbrigghe, Alex Gabe, Brittany Jauquet, Claire Eischer, Tejin Yoon

Michigan Tech Publications

The purpose of this study was to examine prefrontal cortex (PFC) activation, neuromuscular function, and perceptual measures in response to a fatiguing task, following thermal alterations of an exercising arm. Nineteen healthy adults completed three experimental sessions. At baseline, participants performed maximum voluntary isometric contractions (MVIC) of the elbow flexors. Next, participants submerged their right arm in a water bath for 15 min. Cold (C), neutral (N), and hot (H) water temperatures were maintained at 8, 33, and 44◦C, respectively. Following water immersion, participants performed an isometric elbow flexion contraction, at 20% of their MVIC, for 5 min. Ratings of …

Energy Cost Associated With Moving Platforms., Carolyn A Duncan, Scott N Mackinnon, Jacques F Marais, Fabien A Basset

Michigan Tech Publications

Background: Previous research suggests motion induced fatigue contributes to significant performance degradation and is likely related to a higher incidence of accidents and injuries. However, the exact effect of continuous multidirectional platform perturbations on energy cost (EC) with experienced personnel on boats and other seafaring vessels remains unknown.

Objective: The objective of this experiment was to measure the metabolic ECs associated with maintaining postural stability in a motion-rich environment.

Methods: Twenty volunteer participants, who were free of any musculoskeletal or balance disorders, performed three tasks while immersed in a moving environment that varied motion profiles similar to those experienced by …

In-Class Cycling To Augment College Student Academic Performance And Reduce Physical Inactivity: Results From An Rct, Lanae Joubert, Matthew A. Kilgas, Alexandrea Riley, Yuba Gautam, Lars Donath, Scott Drum

Michigan Tech Publications

Most college students sit 14 hours per week on average, excluding sedentary study time. Researchers observing workplace and elementary school settings with active workstations to combat sedentary behavior have shown enhanced cognition without distraction. Until now, incorporating active workstations in college classroom settings remained relatively unexplored. This study’s purpose was to assess academic performance using in-class stationary cycle desks during a semester-long lecture course. Twenty-one college students (19–24 years) enrolled in a lecture course volunteered and were split into traditional sit (SIT) and stationary cycle (CYC) groups randomly, matched on a calculated factor equal to a physical activity (PA) score …