Medical Physiology Commons^™

Low Density Lipoprotein Receptor And Alzheimers Disease, Rangaraj K. Gopalraj

University of Kentucky Doctoral Dissertations

Since apoE allele status is the predominant Alzheimers disease (AD) genetic risk factor, functional single nucleotide polymorphisms (SNPs) in brain apoE receptors represent excellent candidates for association with AD. Therefore, three low density lipoprotein receptor (LDLR) SNPs were evaluated by TaqMan allelic discrimination assays for association with AD and I found that certain haplotypes alter the odds of AD. A SNP within LDLR exon 12, rs688, was identified in silico as neutralizing a putative exon splicing enhancer (ESE). Since LDLR is a major apoE receptor in the brain, I hypothesized that rs688 modulates LDLR splicing in neural tissues and associates …

Studies On The Role Of Acid Sphingomyelinase And Ceramide In The Regulation Of Tace Activity And Tnfα Secretion By Macrophages, Krasimira Rozenova

University of Kentucky Doctoral Dissertations

Acid Sphingomyelinase (ASMase) activity has been proposed to mediate LPS signaling in various cell types. This study shows that in macrophages, ASMase is a negative regulator of LPS-induced TNFα secretion. ASMasedeficient (asm^-/-) mice and isolated peritoneal macrophages produce several fold more TNFα than their wild-type (asm^+/+) counterparts when stimulated with LPS. The mechanism for these differences however is not transcriptional but post-translational.

The TNFα converting enzyme (TACE) catalyzes the maturation of the 26kD precursor (proTNFα) to the active 17kD form (sTNFα). In mouse peritoneal macrophages, the activity of TACE rather than the rate of TNFα mRNA …

Roles Of Emx2 In Odorant Receptor Gene Expression And Olfactory Sensory Neuron Axon Growth, Jeremy Colin Mcintyre

University of Kentucky Doctoral Dissertations

The sense of smell relies upon the detection of odorants by neurons located in the nasal cavity. These neurons, referred to as olfactory sensory neurons (OSNs), line the olfactory epithelium and extend axons that make synaptic connections with mitral/tufted cells in the olfactory bulb. The mechanisms by which these synaptic connections form remain largely unknown. The development of these synaptic connections relies on the axons of immature OSNs innervating the olfactory bulb. The primary goal of this dissertation was to identify components of the mechanisms used by immature OSN axons to innervate the olfactory bulb. To accomplish this goal, a …

Regulation Of Low Density Lipoprotein Receptor Splicing Efficiency, I-Fang Ling

University of Kentucky Doctoral Dissertations

Low density lipoprotein receptor (LDLR) is an apolipoprotein E (apoE) receptor and may play a role in Alzheimer’s disease (AD) development. A single nucleotide polymorphism (SNP), rs688, that has been identified to modulate the splicing efficiency of LDLR exon 12 and is associated with higher cholesterol and AD in some case-control populations. The exon 12 deleted mRNA is predicted to produce a soluble form of LDLR that fails to mediate apoE uptake. To gain additional insights, in this study, I seek to understand the regulation of LDLR splicing efficiency. To identify functional cis-elements within LDLR exon 12, I mutated several …

Ranolazine Attenuates Behavioral Signs Of Neuropathic Pain, Harry J. Gould Iii, Colleen J. Garrett, Renee R. Donahue, Dennis Paul, Ivan Diamond, Bradley K. Taylor

Renee R. Donahue

Ranolazine modulates the cardiac voltage-gated sodium channel (NaV 1.5) and is approved by the FDA in the treatment of ischemic heart disease. Ranolazine also targets neuronal (NaV 1.7, 1.8) isoforms that are implicated in neuropathic pain. Therefore, we determined the analgesic efficacy of ranolazine in a preclinical animal model of neuropathic pain. Both intraperitoneal and oral administration of ranolazine dose-dependently inhibited the mechanical and cold allodynia associated with spared nerve injury, without producing ataxia or other behavioral side effects. These data warrant clinical investigation of the potential use of ranolazine in the treatment of neuropathic pain.

Identification Of Wnt/Β-Catenin Signaling Pathway Components In Human Cumulus Cells, Hong-Xing Wang, Francis R. Tekpetey, Gerald M. Kidder

Physiology and Pharmacology Publications

Signaling via the conserved WNT/β-CATENIN pathway controls diverse developmental processes. To explore its potential role in the ovary, we investigated the expression of WNTs, frizzled (FZD) receptors and other pathway components in human cumulus cells obtained from oocytes collected for in vitro fertilization. Proteins were detected in cultured cells using immunofluorescence microscopy. Protein–protein interactions were analyzed by means of immunoprecipitation. WNT2, FZD2, FZD3 and FZD9 were identified but WNT1, WNT4 and FZD4 were not detected. WNT2 is co-expressed with FZD2, FZD3 and FZD9. Co-immunoprecipitation using WNT2 antibody demonstrated that WNT2 interacts with both FZD3 and FZD9, but only FZD9 antibody …

A Dissociation Between Perception And Action In The Material‐Weight Illusion, Gavin Buckingham, Jonathan Cant, Kai-Ling Kao, Melvyn Goodale

Gavin Buckingham

We examined what forces are applied to objects that elicit this illusion when they are lifted.We predicted that:

(1) Forces on early trials will scale to each participant’s expectations of how much a particular block will weigh ‐ excessive force will be applied to the metal block and insufficient force applied to the polystyrene block.

(2) Forces on later trials will scale to the real weight of each block ‐ identical levels of force applied to all the blocks.

(3) MWI will persist throughout ‐ polystyrene block will feel the heaviest, metal block will feel the lightest.

Grasping And Lifting Different Materials, Gavin Buckingham, Jonathan Cant, Melvyn Goodale

Gavin Buckingham

The material from which an object is made can determine how heavy it feels (Seashore, 1899). Interestingly, a metal block that has been adjusted to have the same size and mass as a polystyrene block will feel lighter than the polystyrene block. We recently showed that participants experiencing this material-weight illusion’ (MWI) do not apply forces that match their perceptual experience of heaviness ‐ just like in the size‐weight illusion ( Flanagan & Beltzner, 2000).

Our previous study showed that forces on early trials were scaled to each participant’s expectations of how much a particular block should weigh ‐ excessive …

Role Of The Lpa2 Receptor In Protecting Against Apoptosis, Shuyu E

Theses and Dissertations (ETD)

Lysophosphatidic acid (LPA) is a naturally occurring lipid mediator. It exists abundantly in biological fluids such as serum, saliva, follicular fluid, seminal fluid and malignant effusions and induces a vast array of biological responses affecting cell growth, survival, differentiation, migration and morphology. We recently identified lysophosphatidic acid (LPA) as a potent antiapoptotic agent for the intestinal epithelium. Based on computational modeling octadecenyl thiophosphate (OTP) was synthesized: a novel rationally designed, metabolically stabilized LPA mimic. OTP was more efficacious than LPA in reducing g-irradiation-, camptothecin-, or TNF-a/cycloheximide-induced apoptosis and caspase 3, 8 and 9 activity in the IEC-6 cell line. The …

Neuroendocrine Peptides Neuropeptide-Y (Npy) And Peptide-Yy (Pyy) Suppress Cl- Secretion And K+ Secretion In Guinea Pig Distal Colon Through Action At Y2-Receptors, Susan T. Halm, Jin Zhang, Dan R. Halm

Neuroscience, Cell Biology & Physiology Faculty Publications

Electrogenic Cl^– and K⁺ secretion in isolated mucosa from guinea pig distal colon measured as short-circuit current (I_sc) and transepithelial conductance (G_t) were stimulated by epinephrine (epi), prostaglandin-E₂ (PGE₂) and carbachol (CCh). neuropeptide-Y (NPY) and peptide-YY (PYY) inhibited by 60% Cl^– secretion activated by either PGE₂ or PGE₂+CCh with EC₅₀’s of 16nM and 6nM, respectively. Neither peptide markedly inhibited the transient component of the PGE₂+CCh response. Immunoreactivity (IR) for NPY was present in enteric ganglia and in proximity with crypts. Basolateral membranes of …

Viral Vectors In The Research Laboratory: Just How Safe Are They?, Dawn P. Wooley, Kimberly Kay Morris, Robert Mcrae, John C. Trefry

Neuroscience, Cell Biology & Physiology Faculty Publications

No abstract provided.

Predictive Measures Of Cognitive Outcome In Adults Sustaining Brain Injury, Herminia De La Rosa-Trujillo

Loma Linda University Electronic Theses, Dissertations & Projects

To date, there is no consistent and accurate outcome prediction method for patients with traumatic brain injury (TBI). Commonly used clinical measures such as the Glasgow Coma Scale (GCS) and traditional radiological methods of x-rays and computed tomography (CT) scans do not always accurately predict patient functional outcome. These radiological methods are adequate in determining gross structural anatomical disturbances, however, they are unable to detect more diffuse cellular damage believed to be responsible for the functional impairments evidenced in patients sustaining TBI. Magnetic resonance imaging allows for various non-invasive sequencing techniques that have demonstrated to be a potentially valuable method …

Effect Of 3-Electrode Electrical Stimulation On Current Delivery And Healing In Chronic Wounds, Hyejin Suh

Loma Linda University Electronic Theses, Dissertations & Projects

Chronic wounds have been an enormous burden on the healthcare system due to their prevalence and the lack of efficacy of current treatment modalities. Over the years, electrical stimulation (ES) has been widely used in the treatment of wounds. Unfortunately, the effectiveness of this treatment is under scrutiny, since many studies have failed to report successive and/or consistent effects of ES on wound healing. This inconsistency may be due to the uneven current produced by the conventional 2-electrode delivery system (2-channel ES) and the reduced resting blood flow resulting from thermally cool treatment rooms. In this study, a new approach …

Investigating The Complexity Of Respiratory Patterns During The Laryngeal Chemoreflex, Andrei Dragomir, Yasemin Akay, Aidan K. Curran, Metin Akay

Dartmouth Scholarship

The laryngeal chemoreflex exists in infants as a primary sensory mechanism for defending the airway from the aspiration of liquids. Previous studies have hypothesized that prolonged apnea associated with this reflex may be life threatening and might be a cause of sudden infant death syndrome. In this study we quantified the output of the respiratory neural network, the diaphragm EMG signal, during the laryngeal chemoreflex and eupnea in early postnatal (3–10 days) piglets. We tested the hypothesis that diaphragm EMG activity corresponding to reflex-related events involved in clearance (restorative) mechanisms such as cough and swallow exhibit lower complexity, suggesting that …

Connexin Expression And Gap Junctional Coupling In Human Cumulus Cells: Contribution To Embryo Quality, Hong-Xing Wang, Dan Tong, Faraj El-Gehani, Francis R. Tekpetey, Gerald M. Kidder

Physiology and Pharmacology Publications

Gap junctional coupling among cumulus cells is important for oogenesis since its deficiency in mice leads to impaired folliculogenesis. Multiple connexins (Cx), the subunits of gap junction channels, have been found within ovarian follicles in several species but little is known about the connexins in human follicles. The aim of this study was to determine which connexins contribute to gap junctions in human cumulus cells and to explore the possible relationship between connexin expression and pregnancy outcome from in vitro fertilization (IVF). Cumulus cells were obtained from IVF patients undergoing intracytoplasmic sperm injection (ICSI). Connexin expression was examined by RT-PCR …

The Synthetic Triterpenoid Cddo-Methyl Ester Modulates Microglial Activities, Inhibits Tnf Production, And Provides Dopaminergic Neuroprotection, Thi A. Tran, Melissa K. Mccoy, Michael B. Sporn, Malú G. Tansey

Dartmouth Scholarship

Recent animal and human studies implicate chronic activation of microglia in the progressive loss of CNS neurons. The inflammatory mechanisms that have neurotoxic effects and contribute to neurodegeneration need to be elucidated and specifically targeted without interfering with the neuroprotective effects of glial activities. Synthetic triterpenoid analogs of oleanolic acid, such as methyl-2-cyano-3,12-dioxooleana-1,9-dien-28-oate (CDDO-Me, RTA 402) have potent anti-proliferative and differentiating effects on tumor cells, and anti-inflammatory activities on activated macrophages. We hypothesized that CDDO-Me may be able to suppress neurotoxic microglial activities while enhancing those that promote neuronal survival. Therefore, the aims of our study were to identify specific …

Exaggerated Natriuretic Response Of Brattleboro Rats To Extracellular Volume Expansion, Susan C. Opava-Stitzer, Emma Fernandez-Repollet, Carmen Rodriguez-Sargent, Jose L. Cangiano, Manuel Martinez-Maldonado

Susan C. Opava-Stitzer

A state of chronic dehydration with reduced plasma volume, decreased blood pressure, and increased plasma renin activity (PRA) has been demonstrated in rats with hereditary hypothalamic diabetes insipidus (DI) rats. In this situation decreased renal perfusion and glomerular filtration rate might result in sodium retention. On the other hand, the DI rat also suffers from mineralocorticoid deficiency which might result in salt wasting. In addition it has recently been shown that in contrast to normal rats, there are no differences between superficial cortical and juxtamedullary nephrons of the DI rat with respect to single nephron filtration rate, glomerular volume, and …

Effect Of Potassium On Plasma Renin Concentration In The Presence And Absence Of Adh (Brattleboro Rat Model), Emma Fernandez-Repollet, Susan C. Opava-Stitzer, Manuel Martinez-Maldonado

Susan C. Opava-Stitzer

Rats with hereditary hypothalamic diabetes insipidus (so-called DI rats) have elevated plasma renin levels. Although the mechanism responsible for this condition has not be elucidated, it seems reasonable to postulate that the absence of ADH and/or the hypokalemia previously reported in these rats might contribute to the elevation of plasma renin concentration (PRC). Evidence in favor of this hypothesis emerges from studies in which both ADH and potassium have been shown to inhibit renin release. In an attempt to examine the relative roles of ADH and potassium in the regulation of renin secretion, PRC was measured in DI rats maintained …

Effect Of Lithium And Antidiuretic Hormone On Plasma Renin Concentration In Diabetes Insipidus Rats (Brattleboro Rat Model), Susan C. Opava-Stitzer

Susan C. Opava-Stitzer

Antidiuretic horomone (ADH) is known to inhibit renin secretion in many species, but the mechanism of this inhibition and its importance in the control of renin secretion are unknown.

Evidence For Baroreceptor Control Of Renin Release, Paul C. Churchill, Richard L. Malvin, Susan C. Opava-Stitzer

Susan C. Opava-Stitzer

Arterial plasma renin activity (PRA) was measured using radioimmunoassay techniques in pentobarbital-anesthetized dogs. Acute saline loading (40-60ml 150mm NaCl/kg body weight, or 20ml 300mm NaCl/kg body weight, i.v.) reduced PRA from control level in 7 dogs. Despite continued increases in filtered and excreted masses of Na, subsequent partial aortic clamping increased PRA in proportion to the degree of reduction in renal perfusion pressure. In 6 other dogs aortic clamping super-imposed on total ureteral occlusion led to changes in PRA which were inversely associated with renal perfusion pressure. These results suggest a controlling mechanism for renin secretion sensitive to some hemodynamic …

Urine Concentration And Dilution In The Rat: Contribution Of Papillary Structures During High Rates Of Urine Flow, Manuel Martínez-Maldonado, Susan C. Opava-Stitzer

Susan C. Opava-Stitzer

To examine the contribution of papillary structures to the overall process of urine dilution and concentration at high rates of flow, studies were performed in unilaterally papillectomized kidneys (PX). Comparison of kidney weights in sham-operated and PX rats revealed a significant reduction in total weight of the latter. Papillary length removed was 3045 ± 423 μm. GFR was reduced by 24% and 45% in sham and PX kidneys when compared to their contralateral controls. Under hydropenic conditions, maximal urine concentrating ability (Umax) was comparable in control and sham kidneys but was 59% less in PX kidneys. Fractional sodium excretion during …

Role Of Water Balance In The Enhanced Potassium Excretion And Hypokalaemia Of Rats With Diabetes Insipidus, Emma Fernandez-Repollet, Manuel Martínez-Maldonado, Susan C. Opava-Stitzer

Susan C. Opava-Stitzer

1. The role of water balance in the hypokalaemia of rats with diabetes insipidus (DI rats) was studied. 2. After a 3-day balance study DI rats had a lower muscle potassium content, and plasma [K+], and the urinary excretion of potassium in response to oral KCl loading was reduced when compared to normal rats. The hypokalaemia was found to be associated with elevated concentrations of potassium in renal medulla and papilla when compared to values in normal Long-Evans rats. 3. During a 9-day balance study urinary potassium excretion was higher than that of normal rats on days 1-3, but not …

Pathophysiology Of Clinical Disorders Of Urine Concentration And Dilution, Manuel Martínez-Maldonado, Susan C. Opava-Stitzer

Susan C. Opava-Stitzer

A defect in the ability to concentrate or dilute the urine can be easily recognized by the maximum or minimum urine concentration the patient is able to achieve. Maximum concentrating ability (Umax) is determined by the urine osmolality reached after a fixed period of dehydration and maximal diluting ability (Umin) by the minimum osmolality of the urine after the oral ingestion of a fixed water-load. These indices, however, do not allow an understanding of the pathophysiological alterations leading to the presence of the defect.

Genetic Regulation Of Hematopoietic Stem Cell Aging, Erin J. Oakley

University of Kentucky Doctoral Dissertations

It is well documented that both quantitative and qualitative changes in the murine hematopoietic stem cell (HSC) population occur with age. In mice, the effect of aging on stem cells is highly strain-specific, thus suggesting genetic regulation plays a role in HSC aging. In C57BL/6 (B6) mice, the HSC population steadily increases with age, whereas in DBA/2 (D2) mice, this population declines. Our lab has previously mapped a quantitative trait locus (QTL) to murine chromosome 2 that is associated with the variation in frequency of HSCs between aged B6 and D2 mice. In these dissertation studies, I first aim to …

Effect Of Chronic Airway Inflammation Induced By Allergen Sensitization On Vagal Bronchopulmonary Sensory Nerves In Rats, Guangfan Zhang

University of Kentucky Doctoral Dissertations

Airway hyperresponsivness (AHR) is one of most prominent pathophysiological features of asthma. Increasing evidence suggests that vagal bronchopulmonary afferents may be involved in the development of AHR. However, the underlying mechanisms are not clear. Therefore, the purpose of this dissertation was to investigate the effect of chronic airway inflammation induced by allergen sensitization on vagal bronchopulmonary afferents. The study was carried out in an animal model of allergic asthma. Brown-Norway rats were sensitized by intraperitoneal Ovalbumin (Ova) and exposed to aerosolized Ova 3 times/week for three weeks. Control rats received the vehicle. In vivo single-fiber recording technique was applied in …

Thermal Sensitivity Of Vagal Pulmonary Sensory Neurons: Role Of Transient Receptor Potential Vanilloid Channels, Dan Ni

University of Kentucky Doctoral Dissertations

Hyperthermia can occur in lungs and airways during both physiological and pathophysiological conditions. A previous study carried out in our laboratory showed that hyperthermia activates and sensitizes vagal bronchopulmonary Cfiber afferents, whether this effect is through a direct action of hyperthermia on sensory nerves is not known. This dissertation study was aimed to investigate the thermal-sensitivity of pulmonary sensory neurons, and the roles of thermalsensitive transient receptor potential vanilloid (TRPV) channels. Whole-cell patch-clamp recordings of neurons isolated from nodose/jugular ganglia were applied in the study. Results of this study showed that hyperthermia directly activates pulmonary sensory neurons, and this effect …

Upa Is Upregulated By High Dose Celecoxib In Women At Increased Risk Of Developing Breast Cancer., Wenyi Qin, Weizhu Zhu, John E Hewett, George Rottinghaus, Yin-Chieh Chen, John T Flynn, Beth Kliethermes, Ferdinando Mannello, Edward R Sauter

Department of Physiology Faculty Papers

BACKGROUND: While increased urokinase-type plasminogen activator (uPA) expression in breast cancer tissue is directly associated with poor prognosis, recent evidence suggests that uPA overexpression may suppress tumor growth and prolong survival. Celecoxib has been shown to have antiangiogenic and antiproliferative properties. We sought to determine if uPA, PA inhibitor (PAI)-1 and prostaglandin (PG)E2 expression in nipple aspirate fluid (NAF) and uPA and PGE2 expression in plasma were altered by celecoxib dose and concentration in women at increased breast cancer risk.

METHODS: NAF and plasma samples were collected in women at increased breast cancer risk before and 2 weeks after taking …

A Developmental Cycle Masks Output From The Circadian Oscillator Under Conditions Of Choline Deficiency In Neurospora, Mi Shi, Luis F. Larrondo, Jennifer J. Loros, Jay C. Dunlap

Dartmouth Scholarship

In Neurospora, metabolic oscillators coexist with the circadian transcriptional/translational feedback loop governed by the FRQ (Frequency) and WC (White Collar) proteins. One of these, a choline deficiency oscillator (CDO) observed in chol-1 mutants grown under choline starvation, drives an uncompensated long-period developmental cycle ( approximately 60-120 h). To assess possible contributions of this metabolic oscillator to the circadian system, molecular and physiological rhythms were followed in liquid culture under choline starvation, but these only confirmed that an oscillator with a normal circadian period length can run under choline starvation. This finding suggested that long-period developmental cycles elicited by nutritional stress …

Anti-Tumor Effect Of Doxycycline On Glioblastoma Cells, Andrea Wang-Gillam, Eric Siegel, Debra A. Mayes, Laura F. Hutchins, Yi-Hong Zhou

Neuroscience, Cell Biology & Physiology Faculty Publications

AIM: Glioblastoma multiforme (GBM) is the most common primary brain tumor in humans, and it is highly invasive. Doxycycline, first identified as an antimicrobial agent, is a nonspecific inhibitor of matrix metalloproteinases (MMPs). Our objective was to investigate the anti-MMP effect of doxycycline at therapeutically acceptable levels on glioma cells in vitro.

METHODS: The MTT assay was used to determine the anti-proliferative effects of doxycycline. MMP2 activity and expression were determined by gelatinase zymography and real-time quantitative RT-PCR, respectively. Cell invasion was assessed by Matrigel invasion assay.

RESULTS: Doxycycline exerted mild anti-proliferative effects on all three glioma cell lines …

The Flagellum Of Pseudomonas Aeruginosa Is Required For Resistance To Clearance By Surfactant Protein A, Shiping Zhang, Francis X. Mccormack, Roger C. Levesque, George A. O'Toole, Gee W. Lau

Dartmouth Scholarship

Surfactant protein A (SP-A) is an important lung innate immune protein that kills microbial pathogens by opsonization and membrane permeabilization. We investigated the basis of SP-A-mediated pulmonary clearance of Pseudomonas aeruginosa using genetically-engineered SP-A mice and a library of signature-tagged P. aeruginosa mutants. A mutant with an insertion into flgE, the gene that encodes flagellar hook protein, was preferentially cleared by the SP-A(+/+) mice, but survived in the SP-A(-/-) mice. Opsonization by SP-A did not play a role in flgE clearance. However, exposure to SP-A directly permeabilized and killed the flgE mutant, but not the wild-type parental strain. P. aeruginosa …