Physiology Commons^™

C-Met Initiates Epithelial Scattering Through Transient Calcium Influxes And Nfat-Dependent Gene Transcription, Peter R. Langford

Theses and Dissertations

Hepatocyte growth factor (HGF) signaling drives epithelial cells to scatter by breaking cell-cell adhesions and migrating as solitary cells, a process that parallels epithelial-mesenchymal transition. HGF binds and activates the c-Met receptor tyrosine kinase, but downstream signaling required for scattering remains poorly defined. This study addresses this shortcoming in a number of ways.A high-throughput in vitro drug screen was employed to identify proteins necessary in this HGF-induced signaling. Cells were tested for reactivity to HGF stimulation in a Boyden chamber assay. This tactic yielded several small molecules that block HGF-induced scattering, including a calcium channel blocker. Patch clamping was used …

Multisensory Integration In Shark Feeding Behavior, Jayne M. Gardiner

USF Tampa Graduate Theses and Dissertations

Multimodal sensory input directs simple and complex behaviors in animals. Most research to date has been limited to studies of individual senses rather than multiple senses working together, leading to important advances in our comprehension of the sensory systems in isolation, but not their complementary and alternative roles in difficult behavioral tasks, such as feeding. In the marine environment, a prey item might emit an odor, create a hydrodynamic disturbance, such as from gill movements or swimming, be visible to the predator, produce a sound, and/or produce a weak electrical field. Therefore, the goal of this study was to investigate …

The Effect Of Physical Activity On The Insulin Response To Frequent Meals, Michael E. Holmstrup

Exercise Science - Dissertations

Long, uninterrupted bouts of sedentary behavior are thought to negatively influence insulin sensitivity, and may impact metabolic function regardless of adherence to general physical activity guidelines. The purpose of this study was to determine the combined effect of physical activity (1 h continuous exercise v. intermittent exercise throughout the day) and meal consumption on glucose excursions, insulin secretion, and appetite markers in obese individuals with prediabetes. Methods: Eleven healthy, obese subjects (>30 kg/m2) with prediabetes underwent 3, 12 h study days including sedentary behavior (SED), exercise (EX; 1h morning exercise, 60-65% VO2 max), and physical activity (PA; 12 hourly, …

Systematics Of Protosteloid Amoebae, Lora Lindley Shadwick

Graduate Theses and Dissertations

Because of their simple fruiting bodies consisting of one to a few spores atop a finely tapering stalk, protosteloid amoebae, previously called protostelids, were thought of as primitive members of the Eumycetozoa sensu Olive 1975. The studies presented here have precipitated a change in the way protosteloid amoebae are perceived in two ways: (1) by expanding their known habitat range and (2) by forcing us to think of them as amoebae that occasionally form fruiting bodies rather than as primitive fungus-like organisms. Prior to this work protosteloid amoebae were thought of as terrestrial organisms. Collection of substrates from aquatic habitats …

Overwintering Energetics Of Lepidoptera: The Effects Of Winter Warming And Thermal Variability., Caroline M. Williams

Electronic Thesis and Dissertation Repository

Winter temperatures are changing rapidly, and although winter warming reduces cold stress for overwintering ectotherms, temperature-mediated increases in metabolic rate can decrease fitness in dormant insects by increasing consumption of energy reserves. Increases in thermal variability also increase energetic demands, due to non-linear thermal response curves. My objective was to quantify the negative effects of winter warming and increases in thermal variability on a range of Lepidopteran species. As overwintering insects rely on lipid catabolism, accurate lipid measurement is central to my dissertation; so I first compared four methods of lipid quantification; concluding thin layer chromatography was the only method …

Impact Of Collateral Enlargement On Smooth Muscle Phenotype, Alexander Jerome Bynum

Master's Theses

Peripheral Artery Disease is a very serious disease characterized by an arterial occlusion due to atherosclerotic plaques. In response to an arterial occlusion, arteriogenesis occurs, causing smooth muscle cells to transition from a contractile to synthetic state. Also following an arterial occlusion, functional impairment was seen in the collateral circuit. An immunofluorescence protocol was developed in order to assess the impact of collateral enlargement (arteriogenesis) on smooth muscle phenotype at various time points. Smooth muscle α-actin was used to mark all smooth muscle cells, Ki-67 was used to label proliferating smooth muscle cells, and a fluorescent nuclear stain was used …

Store-Operated Calcium Channels In The Function Of Intracardiac Neurons, Timetria Bonds

USF Tampa Graduate Theses and Dissertations

Proper autonomic regulation of mammalian cardiac function is dependent upon very complex and precise communication among the intracardiac ganglia and individual neurons within the ganglia. An array of neuromodulators is found within the ganglia that direct neuronal activity by modulating the movement of calcium. The current study determines that opioidergic agonists, which have been found to contribute to severe cardiac disease states and intracellular calcium mobilization, are also responsible for changes in the function of the intracardiac neuron via their effects on store-operated calcium channels (SOCs).

Previous studies suggest that phosphorylation plays a role in SOC regulation. Using Fura-2 calcium …

Morpho-Physiological Analysis Of Interneuronal Populations In The Rat Piriform Cortex Before And After Kindling Induced Epilepsy, Cezar Gavrilovici

Electronic Thesis and Dissertation Repository

The piriform cortex (PC) is involved in olfactory sensory processing, associative learning tasks and is highly seizurogenic. Understanding how interneurons participate in these behaviours, especially their contribution in epileptogenic mechanisms, is hampered by an incomplete understanding of their functional and morphological diversity. The hypothesis in this work is that kindling-induced epilepsy alters the firing properties of PC interneuronal populations. Altered/impaired interneuronal firing could lead to abnormal processing in the PC and epileptogenesis. Therefore it was important to first identify and describe interneuronal morpho-functional properties in the unkindled brain and then to assess the electrophysiological parameters following kindling.

Based on interneuronal …

Trace Metal Limitation And Its Role In Oxidative Stress Of Coral Algal Symbionts; Implications For Thermally Induced Coral Bleaching Events., Katrina Lynn Iglic

Electronic Thesis and Dissertation Repository

Coral bleaching, the process in which corals expel their photosynthetic symbionts (Genus Symbiodinium), is caused by high temperature and irradiance stress. The synergistic effect of each stressor is the generation of damaging reactive oxygen and nitrogen species (ROS and RNS), which are normally mitigated physiologically by antioxidant enzyme activity. Antioxidant enzymes require iron, copper, manganese and zinc in their structure and the limited nature of these trace metals in reef environments may enhance ROS production under elevated temperature and irradiance. The hypothesis tested within this thesis was that a limited availability of the trace metals Fe, Mn, Cu and …

Aging And Sympathetic Neurotransmission In Two Strains Of Rats That Differ In Longevity And Immune Profiles, Sam David Perez

Loma Linda University Electronic Theses, Dissertations & Projects

Age-related changes in sympathetic neurotransmission in immune organs may be associated with immunosenescence; however no causal relationship has been established. From previous studies in Fischer rats (F344), we have found that during middle age, sympathetic nerve activity (SNA) rises in the spleen followed by a decline in noradrenergic (NA) innervation. Also, increased sympathetic signaling via betaadrenergic receptor (β-AR) and reduced proliferation of lymphocytes are evident with increasing age. Although SNA progressively rises with age, effects of age on sympathetic factors may be different across rat strains. If causal relationships exist between sympathetic activity and immune function, they may be related …

Impaired Resistance Artery Reactivity Following Arteriogenesis, Michael (Mike) Machado

Biomedical Engineering

No abstract provided.

Purine Transport And Metabolism In Microvascular Endothelial Cells, Derek B J Bone

Electronic Thesis and Dissertation Repository

The microvascular endothelium serves as the barrier between the blood and perfused tissues. Proper function of the endothelium is dependent on the ability of the endothelial cells to produce nitric oxide and form tight junctions between themselves. Dysfunction occurs when stresses overwhelm the endothelial cell, with oxidative stress being a leading cause. Intracellular metabolism of purine nucleosides and nucleobases has been implicated in the production of oxidative stress. Nucleosides (e.g. adenosine) and nucleobases (e.g. hypoxanthine) are moved across cell membranes by a specialized family of proteins called equilibrative nucleoside transporters (ENTs).

We characterized primary human cardiac microvascular endothelial cells (MVECs) …

Decoding Motor Intentions From Human Brain Activity, Jason P. Gallivan

Electronic Thesis and Dissertation Repository

“You read my mind.” Although this simple everyday expression implies ‘knowledge or understanding’ of another’s thinking, true ‘mind-reading’ capabilities implicitly seem constrained to the domains of Hollywood and science-fiction. In the field of sensorimotor neuroscience, however, significant progress in this area has come from mapping characteristic changes in brain activity that occur prior to an action being initiated. For instance, invasive neural recordings in non-human primates have significantly increased our understanding of how highly cognitive and abstract processes like intentions and decisions are represented in the brain by showing that it is possible to decode or ‘predict’ upcoming sensorimotor …

Association Between T Cells-Related Gene Expression And Fibrosis Progression In Hcv Recurrence Disease., Alexander Philip

Theses and Dissertations

Hepatitis C virus (HCV) is the major cause of chronic hepatitis worldwide and a leading cause for liver transplant. Unfortunately, graft HCV infection is a universal phenomenon despite of pre-transplant prophylactic strategies. Acute HCV infection and innate immune responses elicit an inflammatory scenario that triggers the recruitment of adaptive immune response cells. Of those chronically infected, 30% experience accelerated fibrosis with concomitant cirrhosis development within 5 years post-LT and require re-transplant. With many patients responding unfavorably to antivirals and ineffective vaccines, much attention is now placed on T cell immunity in controlling HCV infection. This study represents a retrospective analysis …

Mechanisms Of Prenatal High-Salt "Fetal Programming" Resulting In Stress Hyperresponsiveness In The Adult Female Offspring In The Sprague Dawley Rat., Clinton L. Johnson

Theses and Dissertations

Female offspring of Sprague-Dawley rats fed a high-salt diet (HS) during pregnancy show an enhancement of mean arterial pressure (MAP) and heart rate (HR) response to acute stress in adulthood compared to offspring whose mothers were fed a normal-salt diet (NS) [1]. In the present study, we first examined the expression of soluble epoxide hydrolase (SEH) protein in brain tissue. Whole brains were collected and SEH gene (EPHX2) mRNA and SEH protein expression were analyzed using RT-PCR and Western blot, respectively. mRNA levels were relatively decreased in high-salt rats (1.0 ± 0.32 NS vs 0.39 ± 0.07 HS, n=6). However, …

Molecular Pathways Involved In Calcineurin Inhibitor Nephrotoxicity In Kidney Allograft Transplants, Huong Nguyen

Theses and Dissertations

ABSTRACT MOLECULAR MECHANISMS AND GENE SIGNATURES INVOVLED IN CALCINEURIN INHIBITOR NEPHROTOXICITY IN KIDNEY ALLOGRAFT By Huong Le Diem Nguyen, M.S. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Physiology at Virginia Commonwealth University. Virginia Commonwealth University, 2011. Major Director: Valeria Mas, Ph.D. Associate Professor, Department of Surgery and Pathology Director of Molecular Transplant Research Laboratory, Division of Transplant Calcineurin inhibitors (CNI), cyclosporin A and tacrolimus, are potent immunosuppressive agents but induce toxicities causing damages and graft dysfunction, and have been suggested to contribute to late-term loss of graft in kidney transplant …

The Proteomic Response Of Ciona Intestinalis To Ocean Acidification And Acute Heat Stress: Impacts Of Global Climate Change In Coastal Marine Systems, Michael Dennis Dwyer Jr.

Biological Sciences

No abstract provided.

Genetic And Nutritional Studies To Elucidate The Role Of Adipose Tissue In The Pathogenesis Of Metabolic Syndrome, Nishan Sudheera Kalupahana

Doctoral Dissertations

Obesity is a major health problem in the United States and worldwide. It increases the risk for type-2 diabetes and cardiovascular diseases. A chronic low-grade inflammation occurring in white adipose tissue (WAT) is causally linked to the development of insulin resistance (IR), metabolic syndrome and obesity-associated chronic diseases. The aim of this dissertation research was to elucidate the WAT function in metabolic syndrome using genetic (overexpression of an adipose pro-inflammatory hormone, angiotensinogen) and nutritional manipulations/approaches (caloric restriction and omega-3 fatty acids), with specific emphasis on the role of inflammation.

Previous research indicates that WAT renin-angiotensin system (RAS) is overactivated in …

The Role Of The Androgen Receptor Cofactor P44/Wdr77 In Astrocyte Activation, Bryce H. Vincent

Dissertations & Theses (Open Access)

Astrogliosis is induced by neuronal damage and is also a pathological feature of the major aging-related neurodegenerative disorders. The mechanisms that control the cascade of astrogliosis have not been well established. In a previous study, we identified a novel androgen receptor (AR)-interacting protein (p44/WDR77) and found that it plays a critical role in the control of proliferation and differentiation of prostate epithelial cells. In the present study, we found that deletion of the p44 gene in the mouse brain caused accelerated aging with dramatic astrogliosis. The p44/WDR77 is expressed in astrocytes and loss of p44/WDR77 expression in astrocytes leads to …

Embryonic Development Of The Grass Shrimp, Palaemonetes Pugio, And The Influence Of Salinity On Cardiac Physiology, Amie Lynn Romney

UNLV Theses, Dissertations, Professional Papers, and Capstones

The grass shrimp, Palaemonetes pugio, inhabit the brackish waters along the Atlantic coast of North America and are a key component of the estuarine ecosystem. These decapod shrimp can tolerate large fluctuations in environmental parameters including daily and seasonal fluctuations in salinity between 0 to 55 parts per thousand (seawater at 30-32 ppt). Any observed distribution patterns of adult P. pugio in relation to salinity may be accounted for by their relative ability to tolerate a range in salinity and their ability to maintain internal water volumes and cardiac performance in the earliest life stage, the embryonic period. This thesis …

Mitochondrial Metabolic Suppression And Reactive Oxygen Species Production During Hypometabolism In Mammals, Jason Cl Brown

Electronic Thesis and Dissertation Repository

During hibernation, daily torpor, and fasting, mammals reduce metabolic rate (MR) up to 99%, 95%, and 30%, respectively, compared to resting levels. Mitochondrial metabolic suppression likely contributes to this MR reduction, and the first objective of this study was to determine the relative contributions of active, regulated inhibition and passive thermal effects as body temperature (T_b) falls, to mitochondrial metabolic suppression, and to examine the mechanisms involved using top-down elasticity analysis and novel statistical approach. The second objective of this study was to determine how mitochondrial metabolic suppression affects mitochondrial reactive oxygen species (ROS) production, a topic which …

Opioid Addiction Treatments During Pregnancy And Their Effects On Axonal Growth And Myelination In The Developing Central Nervous System, Manisha Magar

Theses and Dissertations

Treatment with buprenorphine represents a promising alternative for pregnant opioid addicts but there is a need to understand potential effects on nervous system development. We previously showed effects of perinatal exposure to buprenorphine on axonal caliber and myelination in 26-day-old rat corpus callosum. These changes, detected at the end of rapid brain myelination and accompanied by earlier oligodendrocyte maturation, suggested interference with mechanisms coordinating axonal growth and myelination. To better understand buprenorphine actions and to establish whether these effects extend to the spinal cord, we analyzed the corpus callosum and corticospinal tract at 16 days of age, just before the …

Quantitative Analysis Of Contactin-Associated Protein And Voltage-Gated Sodium Channel Isoform 1.6 Following Experimental Diffuse Traumatic Brain Injury, Daniel Gardiner

Theses and Dissertations

Traumatic axonal injury (TAI) contributes to the mortality and morbidity following diffuse traumatic brain injury (TBI). Previous work has shown that following TBI, alterations in the molecular domains of axons result in TAI. It is currently posited that injury induced ionic flux is responsible for activating deleterious proteolytic cascades, resulting in altered distributions of axonal components. However, the underlying mechanism of this progressive pathology remains elusive. This study further explores the hypothesis that altered molecular domains contributes to the progressive intra-axonal changes that characterize TAI. Using a rodent model of impact acceleration TBI we examined the expression of nodal and …

Role Of Rac1 In Myocardial Tnf-Alpha Expression In Sepsis, Ting Zhang

Electronic Thesis and Dissertation Repository

Tumor necrosis factor-a (TNF-alpha) is a pro-inflammatory cytokine and its high levels of expression in the heart leads to cardiac dysfunction in sepsis. However, the underlying molecular mechanisms of regulating myocardial TNF-alpha expression are not fully understood. The aim of this thesis was to investigate the role of Rac1 in myocardial TNF-alpha expression and cardiac dysfunction during sepsis. Studies were performed using cultured neonatal cardiomyocytes and a mouse model of endotoxemia.

PI3K-mediated Rac1 activation is required for induction of TNF-alpha mRNA and protein expression in cardiomyocytes and cardiac dysfunction during endotoxemia. Rac1 promotes TNF-alpha mRNA expression via NADPH oxidase/ERK1/2 and …

Calcineurin Is Required For Trpv1-Induced Ltd Of Ca1 Stratum Radiatum Interneurons, Tyron Deray Jensen

Theses and Dissertations

Learning and memory in the brain are thought to be dependent on synaptic plasticity. In response to sensory input, synapses can be strengthened or weakened, known as long-term potentiation or long-term depression (LTD), respectively. Transient receptor potential vanilloid 1 (TRPV1) has been shown to mediate a novel form of presynaptic LTD in hippocampal interneurons. TRPV1 is currently being heavily studied in the PNS and being targeted by pharmaceuticals for its anti-nociceptive and anti-inflammatory properties. However, much less is known regarding TRPV1 function in the CNS, including the signal mechanism mediating hippocampal LTD despite its obvious importance. Here we performed whole-cell …

Receptor Influences In Girk Current Activation And Desensitization, Gyu Park

Theses and Dissertations

G protein-coupled receptors (GPCRs) are seven-transmembrane domain receptors that sense extracellular signal and activate intracellular signaling pathways. Metabotropic glutamate receptor 2 (mGluR2) is one of the GPCRs coupled to Gi/o proteins whose Gβγ subunits stimulate G protein-gated inwardly rectifying K+ channels (GIRKs). Previous experiments demonstrated that in planar lipid bilayer both active forms of G proteins [Gα (GTPγS-stimulated) and Gβγ subunits] were required to activate GIRK channels in the absence of the receptor, but surprisingly, the Gβγ subunit alone could activate GIRK channel in the presence of GPCR. Currently, it is not clear whether GPCRs play a role beyond catalyzing …

The Effects Of Β-Amyloid On Α7 Nicotinic Acetylcholine Receptors Expressed In Xenopus Oocytes, Malia L. Anderson

Theses and Dissertations

The exact mechanism and progression of Alzheimer's disease (AD) at present is not fully understood. In patients suffering from AD, damage to the hippocampal region and impairment of learning and memory is present. It is also known that a buildup of β-amyloid plaques occur in AD patients and that β-amyloid interacts with some subtypes of neuronal nicotinic acetylcholine receptors (neuronal nAChRs). These receptors are composed of five subunits. The most prevalent nAChR subunit composition through the brain as a whole is α7. Previous data produced from our lab suggests that α7 nAChRs are also one of the most prevalent subunits …

Plantar Pressure Distribution Differences In Physically Active Individuals With And Without Functional Ankle Instability During A Side Cut, J'Nai Pittman

Human Movement Sciences & Special Education Theses & Dissertations

Context: Functional ankle instability (FAI) is a popular condition in the physically active population. There is a surplus of evidence to demonstrate how FAI decreases proprioception, balance, and overall athletic performance. However, to date there is no evidence that demonstrates how F AI correlates to alterations in plantar pressure distribution differences in a physically active population while completing athletic tasks. Objective: To assess differences in plantar pressure distributions while completing a side cut in individuals with and without FAI. Design: Observational case-control. Setting: Outdoor field turf and research laboratory. Participants: Fifty ankles from physically active individuals (FAI: age= 21.47±3.02 yrs; …

Why Is There Still So Much Confusion About Vo2 Plateau? A Re-Examination Of The Work Of A.V. Hill, Richard Vincent Castle

Masters Theses

Maximal oxygen uptake (VO_2max) is regarded as the gold standard for assessing aerobic fitness. In 1923, Hill et al. proposed that VO_2max represents the maximal ability of the body to take in and consume O₂ during strenuous exercise. Recently, however, controversy has arisen over the issue of whether a leveling off, or "plateau" in VO₂ is necessary to verify attainment of VO_2max. Purpose: To compare two different VO_2max protocols and determine if both protocols show direct evidence of an upper limit on VO₂. Methods: Nine runners (18-35 years old) completed …

Ischemia Impairs Vasodilation In Skeletal Muscle Resistance Artery, Kyle Remington Struthers

Master's Theses

Functional vasodilation in arterioles is impaired with chronic ischemia. We sought to examine the impact of chronic ischemia and age on skeletal muscle resistance artery function. To examine the impact of chronic ischemia, the femoral artery was resected from young (2-3mo) and adult (6-7mo) mice and the profunda femoris artery diameter was measured at rest and following gracilis muscle contraction 14 days later using intravital microscopy. Functional vasodilation was significantly impaired in ischemic mice (14.4±4.6% vs. 137.8±14.3%, p<0.0001 n=8) and non-ischemic adult mice (103.0±9.4% vs. 137.8±14.3%, p=0.05 n=10). In order to analyze the cellular mechanisms of the impairment, a protocol was developed to apply pharmacological agents to the experimental preparation while maintaining tissue homeostasis. Endothelial and smooth muscle dependent vasodilation were impaired with ischemia, 39.6 ± 13.6% vs. 80.5 ± 11.4% and 43.0 ± 11.7% vs. 85.1 ± 10.5%, respectively. From this data, it can be supported that smooth muscle dysfunction is the reason for the observed impairment in arterial vasodilation.