Physiology Commons^™

Frontiers In The Self-Assembly Of Charged Macromolecules, Khatcher O. Margossian

Doctoral Dissertations

The self-assembly of charged macromolecules forms the basis of all life on earth. From the synthesis and replication of nucleic acids, to the association of DNA to chromatin, to the targeting of RNA to various cellular compartments, to the astonishingly consistent folding of proteins, all life depends on the physics of the organization and dynamics of charged polymers. In this dissertation, I address several of the newest challenges in the assembly of these types of materials. First, I describe the exciting new physics of the complexation between polyzwitterions and polyelectrolytes. These materials open new questions and possibilities within the context …

Prefrontal Coding Of Naturalistic Working Memory: Mechanisms During Normal Maintenance And Modelled Disease, Megan P. Roussy

Electronic Thesis and Dissertation Repository

Neural activity in the primate lateral prefrontal cortex (LPFC) has been causally linked to working memory (WM) ⁠— the brief maintenance and mental manipulation of information. Primates use WM to perform tasks in complex contexts; however, neural mechanisms of WM and the pathophysiology related to WM deficits have traditionally been studied using simple tasks that deviate from naturalistic conditions. This raises the question, how is WM processed in naturalistic conditions? To explore this, I trained two macaque monkeys on a spatial WM task set in a naturalistic virtual environment. During the task, a target was presented in 1 of 9 …

Expression Of Claudins In Gill And Opercular Membranes In Relation To Osmoregulation In Euryhaline Atlantic Killifish, Fundulus Heteroclitus, Allison Mcfarland

Graduate Theses and Dissertations

Atlantic killifish (Fundulus heteroclitus) are euryhaline teleosts, which means they can thrive in environments with varying salinities, ranging from concentrated seawater (SW) to dilute fresh water (FW) and thus survive in estuaries. To be able to maintain ionic and osmotic homeostasis in these diverse salinities, osmoregulatory organs like gill and opercular membrane must be able to adjust the permeability and transport of water and ions. The surface epithelia in these organs need to prevent the passive flux of ions and water in a drastically changing environment, while being able to switch between active ion secretion or uptake dependent upon environmental …

Perception Of Illness And Its Association With Willingness To Adhere To Treatment In Chronic Hepatitis C Patients With New Diagnosis Of Nonalcoholic Fatty Liver Disease, Carmel Kruse

The Eleanor Mann School of Nursing Student Works

Chronic liver disease is becoming the most common cause of mortality, morbidity, and utilization of healthcare services globally. Both nonalcoholic fatty liver disease (NAFLD) and chronic hepatitis C (CHC) are frequent causes of chronic liver disease. Recently, there have been significant findings on the relationship between NAFLD and CHC; patients with CHC have a higher incidence of NAFLD. The introduction of direct-acting antivirals has cured more CHC patients than ever before. Unfortunately, the current interventions for NAFLD requiring behavioral change remain ineffective. Patient’s ability to follow advice depends largely on their health beliefs; therefore, understanding their illness perception is an …

Positive Rate-Dependent Action Potential Prolongation By Modulating Potassium Ion Channels, Candido Cabo

Publications and Research

Pharmacological agents that prolong action potential duration (APD) to a larger extent at slow rates than at the fast excitation rates typical of ventricular tachycardia exhibit reverse rate dependence. Reverse rate dependence has been linked to the lack of efficacy of class III agents at preventing arrhythmias because the doses required to have an anti-arrhythmic effect at fast rates may have pro-arrhythmic effects at slow rates due to an excessive APD prolongation. In this report we show that, in computer models of the ventricular action potential, APD prolongation by accelerating phase 2 repolarization (by increasing I_Ks) and decelerating …

The Effect Of Breathing Patterns Common To Competitive Swimming On Gas Exchange And Muscle Deoxygenation During Heavy-Intensity Fartlek Exercise, Kevin J. Grossman

Electronic Thesis and Dissertation Repository

The purpose of this study was to compare the respiratory and muscle deoxygenation (HHb) responses of regulated breathing versus free-breathing, during continuous exercise (CONLD) and intermittent 5s breath holds (BH) (CONLD-BH), intermittent 5s sprint (FLK) and combined 5s BH and sprint (FLK-BH) followed by 25s of free-breathing. Oxygen uptake(V̇O₂)was unchanged between CONLD (2.12±0.35L/min) and CONLD-BH (2.15±0.42L/min; p=0.116), and FLK (2.24±0.40L/min) and FLK-BH (2.20±0.45L/min; p=0.861). Δ[Hb_tot]: CONLD (3.3±1.6µM) > CONLD-BH (-2.5±1.2µM; ∆177%; p<0.001), but unchanged between FLK (2.0±1.6µM) and FLK-BH (0.82±1.4µM; p=0.979). Δ[HHb]: CONLD (7.3±1.8µM) > CONLD-BH (7.0±2.0µM; ∆4%; p=0.011), and FLK (6.7±1.8µM) < FLK-BH (8.7±2.4µM; p<0.001). It is suggested that the unchanged V̇O₂ between CONLD and CONLD-BH was supported by increased deoxygenation, reflected by decreased ∆[Hb_tot] and blunted …

Linking Spinal Cord Circuits With Upper Limb Sensorimotor Control In Adults With Cerebral Palsy, Saihari Dukkipati

Theses & Dissertations

Cerebral palsy (CP) is the most common neurological disorder originating in childhood, but most of the people living with CP are currently adults. While people with CP continue to get older, the amount of research focused on adults has been rather limited. The early childhood insults leading to CP are thought to originate in the brain, but the effects on the entire neuromuscular system across the lifespan have only recently started to be explored. Of note, recent neuroimaging evidence suggests that the cervical spinal cord structure is atypical in adults with CP. However, it is largely unclear how the neurophysiological …

The Influence Of Temperature And Body Size On Food Consumption In Prairie Lizards (Sceloporus Consobrinus), Morgan Pelley

Biological Sciences Undergraduate Honors Theses

Understanding the effect of temperature on physiological and digestive processes, such as voluntary consumption rate, is critical for assessing the impact of climate change. Food consumption is required for lizard survival and reproduction and its rate is dependent on temperature. For ectotherms, as temperatures increase, the amount of food consumed to meet the energy requirements related to survival and reproduction must also increase. Information on the amount of food voluntarily consumed may aid in determining if lizards can meet energy requirements. Such information could also aid in predicting survival of lizard populations, through construction of predictive climate change models. In …

Increased Corticospinal Inhibition Following Submaximal And Maximal Muscle Activation In Humans, Alexander D. Paish

Electronic Thesis and Dissertation Repository

Following short duration, high intensity muscle activation, there is an enhancement of muscle contractile properties, termed postactivation potentiation (PAP). Corticospinal inhibition, assessed by an increased silent period (SP), was shown previously to increase following voluntary or electrically evoked PAP. Although these changes coexist, the direct effect of PAP on corticospinal inhibition has not been systematically evaluated. In 10 participants, SP duration was measured pre and post 10s maximal and submaximal, voluntary and electrically stimulated contractions. Following maximal contractions, mean twitch torque was enhanced ~180% with no enhancement at submaximal levels (~102%). The SP duration was prolonged following all conditions: ~12% …

Mechanisms Of Diapause And Cold Tolerance In The Colorado Potato Beetle, Jacqueline E. Lebenzon

Electronic Thesis and Dissertation Repository

Many temperate insects enter diapause (a state of dormancy) and enhance their cold tolerance to survive the winter. During diapause, the Colorado potato beetle (CPB, Leptinotarsa decemlineata, Coleoptera: Chrysomelidae) stops developing, lowers its metabolism, and changes its physiology to avoid freezing. The extent to which diapause confers cold tolerance in CPB is currently unknown. In my thesis, I used CPB to improve our understanding of the mechanisms underlying metabolic suppression during diapause and cellular protection at sub-zero temperatures in insects. First, I used RNA-sequencing (RNA-seq) to compare gene expression in two metabolically important tissues (the fat body and flight muscle) …

Supplemental Peer Instruction In Physiologic Core Concept Education, Austin Choat

Honors Theses

The objective of my thesis project was to create and research the importance of supplemental learning videos within core physiological concepts identified by the Advancement of Physiological Principles for the purpose of assisting Dr. Kim Hansen in better educating students with less extensive foundational knowledge of chemical and biological sciences. Through researching the benefits of peer instruction, identifying core physiological concepts crucial to wholistic physiology education, and describing a student population hypothesized to benefit substantially from the work, I created educational videos to aid Dr. Hansen in her work as an educator and in the educational research she is striving …

Time-Dependent Alteration In The Chemoreflex Post-Acute Lung Injury, Kajal Kamra, Nikolay Karpuk, Ryan Adam, Irving H. Zucker, Harold D. Schultz, Han-Jun Wang

Journal Articles: Cellular & Integrative Physiology

Acute lung injury (ALI) induces inflammation that disrupts the normal alveolar-capillary endothelial barrier which impairs gas exchange to induce hypoxemia that reflexively increases respiration. The neural mechanisms underlying the respiratory dysfunction during ALI are not fully understood. The purpose of this study was to investigate the role of the chemoreflex in mediating abnormal ventilation during acute (early) and recovery (late) stages of ALI. We hypothesized that the increase in respiratory rate (fR) during post-ALI is mediated by a sensitized chemoreflex. ALI was induced in male Sprague-Dawley rats using a single intra-tracheal injection of bleomycin (Bleo: low-dose = 1.25 mg/Kg or …

The Impact Of Food Deprivation On Cardiovascular Physiology, Steven Philip Stelly

Dissertations, Master's Theses and Master's Reports

Introduction: Despite the commonality of fasting, there still remains a lack of scientific research, specifically in regard to the impact of fasting on cardiovascular physiology. Thus, the goal of this research project was to further explore the relationship between fasting and cardiovascular physiology. Hypothesis: The hypothesis of this research project was that a 24-hr fast would likely lead to increased BP and HR, along with blood biomarker changes, and that experiencing this 24-hr fast twice a week would lead to reduced BP and HR along with altered circulating blood biomarker levels. Methods: In order to test these hypotheses, cardiovascular and …

Regulation Of Skeletal Muscle Plasticity By The Gut Microbiome, Taylor R. Valentino

Theses and Dissertations--Physiology

Recent evidence suggests that the gut microbiome could play a role in skeletal muscle plasticity, providing novel treatments for muscle wasting diseases and/or performance enhancements. I first sought to determine if the gut microbiome is necessary for skeletal muscle adaptation to exercise. Forty-two, four-month old, female C57Bl/6J underwent nine weeks of weighted wheel running or remained in cage with a locked wheel, without or without the administration of antibiotics (treated). In response to wheel running, I found that antibiotic depletion of the microbiome led to a blunted hypertrophic response in the soleus muscle as measured by normalized muscle wet weight …

Comparative Genomics, Evolutionary Epidemiology, And Rbd-Hace2 Receptor Binding Pattern In B.1.1.7 (Alpha) And B.1.617.2 (Delta) Related To Their Pandemic Response In Uk And India, Chiranjib Chakraborty, Ashish Ranjan Sharma, Manojit Bhattacharya, Bidyut Mallik, Shyam Sundar Nandi, Sang-Soo Lee

Journal Articles: Cellular & Integrative Physiology

BACKGROUND: The massive increase in COVID-19 infection had generated a second wave in India during May-June 2021 with a critical pandemic situation. The Delta variant (B.1.617.2) was a significant factor during the second wave. Conversely, the UK had passed through the crucial phase of the pandemic from November to December 2020 due to B.1.1.7. The study tried to comprehend the pandemic response in the UK and India to the spread of the B.1.1.7 (Alpha, UK) variant and B.1.617.2 (Delta, India) variant.

METHODS: This study was performed in three directions to understand the pandemic response of the two emerging variants. First, …

T-Lymphocyte Tyrosine Hydroxylase Regulates T H 17 T-Lymphocytes During Repeated Social Defeat Stress, Safwan K. Elkhatib, Cassandra M. Moshfegh, Gabrielle F. Watson, Adam J. Case

Journal Articles: Cellular & Integrative Physiology

Posttraumatic stress disorder (PTSD) is a debilitating psychiatric disorder which results in deleterious changes to psychological and physical health. Patients with PTSD are especially susceptible to life-threatening co-morbid inflammation-driven pathologies, such as autoimmunity, while also demonstrating increased T-helper 17 (T_H17) lymphocyte-driven inflammation. While the exact mechanism of this increased inflammation is unknown, overactivity of the sympathetic nervous system is a hallmark of PTSD. Neurotransmitters of the sympathetic nervous system (i.e., catecholamines) can alter T-lymphocyte function, which we have previously demonstrated to be partially mitochondrial redox-mediated. Furthermore, we have previously elucidated that T-lymphocytes generate their own catecholamines, and strong …

Physician Assisted Dying (Pad): An Investigation Into The Mechanistic Action Of Opioid, Benzodiazepine, And Barbiturate Administration As An Alternative Measure To Forgoing Life Sustaining Treatment And Aggressive Palliation., Jordana Chanel Deighton

CMC Senior Theses

Whilst modern medicine has increased longevity, the rise in life expectancy has brought about new struggles, namely that of aging and age related disease. Thus, humanity has been presented with a new problem: at what point is death preferable to aggressive life-prolonging treatment in the face of inevitable death? And if so, what right do individuals have to control the circumstances of their death? In the West, traditionally, individuals who seek to end their own lives in the face of terminal illness opt for forgoing artificial hydration and nutrition. Driven by an increase in desire for autonomous dignified death, a …

Effects Of Mindfulness And Stress Management On Neurocardiovascular And Psychological Outcomes, Aditi P. Vyas

Dissertations, Master's Theses and Master's Reports

There has been a higher prevalence of developing anxiety due to frequent episodes of stress among adults in recent years. Chronic anxiety can contribute to the prevalence of elevated blood pressure and hypertension. High anxiety and stress also contribute to overactivation of the sympathetic nervous system which can be quantified by increased muscle sympathetic nerve activity (MSNA). Sympathetic overactivation can lead to vasoconstriction and loss of arterial elasticity. Anxiety, MSNA, blood pressure, and arterial stiffness are all interconnected, thus studying these relationships is crucial to understand the underlying mechanisms for prevention and treatment of cardiovascular disease (CVD). Non-pharmacological and mind-body …