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Theses and Dissertations

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Articles 271 - 300 of 308

Full-Text Articles in Physiology

The Role Of Fgfr4 In Trigeminal Placode Cell Development, Stephanie Beth Reynolds Mar 2006

The Role Of Fgfr4 In Trigeminal Placode Cell Development, Stephanie Beth Reynolds

Theses and Dissertations

In vertebrate embryos, the ophthalmic trigeminal (opV) placode contributes sensory neurons to the trigeminal ganglion during development of the peripheral nervous system. FGFR4 is expressed transiently in the trigeminal placode as cells undergo an epithelial-mesenchymal transition and begin to migrate toward the condensing ganglion. Because of the restricted spatiotemporal expression of FGFR4 in the opV placode, it was hypothesized that FGFR4 is necessary for the process of epithelial-mesenchymal transition in the opV placode. Using electroporation, an FGFR4 inhibitory gene construct was introduced into 6—10 somite stage chick embryos. This secreted inhibitory form of the FGFR4 gene blocked endogenous FGFR4 signaling, …

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The Role Of Pax3 In Neuronal Differentiation Of The Ophthalmic (Opv) Trigeminal Placode And Neural Tube During Chicken Embryonic Development, James R. Bradshaw Mar 2006

The Role Of Pax3 In Neuronal Differentiation Of The Ophthalmic (Opv) Trigeminal Placode And Neural Tube During Chicken Embryonic Development, James R. Bradshaw

Theses and Dissertations

Pax3 has been used as a valuable marker in research aimed at understanding tissue interactions involved in trigeminal ophthalmic (opV) placode development. While Pax3 expression coincides with opV neuron specification, the function of Pax3 in these cells has not previously been investigated. Splotch mutant mice (which lack Pax3) have a reduced trigeminal ganglion; however it is not clear whether this reduction is due to neural crest or placode cells. We have used electroporation in the chick model system to block or ectopically express Pax3 at key times in opV placode development. Using several markers of placode cell differentiation, we have …

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Apparent Digestibility In Lamas (Lama Glama), Fed With Brazilian Grass And Wheat In The C.E.A.C., William Edson Velez Contacayo Jan 2006

Apparent Digestibility In Lamas (Lama Glama), Fed With Brazilian Grass And Wheat In The C.E.A.C., William Edson Velez Contacayo

Theses and Dissertations

Considering the activity of introducing genetic resources with a high potential for yield, and with a wide adaptation range, it is possible to strengthen the cattle production system, through the production of adequate forage in quality, and quantity. Brazilian grass was introduced to Bolivia in 1974 for demonstrating excellent forage characteristics, and great adaptation qualities to the different ecosystems of the Andes. The material was introduced through the Experimental Station of Patacamaya, with their material supplied through the Experimental Station of Obonuco (Colombia). The following study was conducted at the Agropecuary Experimental Center of Condori, located 49 km. north of …

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The Effects Of Hemoglobin-Based Oxygen Carriers On Mean Arterial Pressure, Arteriolar Diameter, And Nitric Oxide In The Microcirculation, Veronique C. Hionis Jan 2006

The Effects Of Hemoglobin-Based Oxygen Carriers On Mean Arterial Pressure, Arteriolar Diameter, And Nitric Oxide In The Microcirculation, Veronique C. Hionis

Theses and Dissertations

In the US today, blood transfusion is safer than ever. Nevertheless, the century-old quest for a suitable blood substitute persists. The elimination of unwanted side effects, especially transfusion-transmitted diseases, the problems and high cost factor involved in collecting and storing human blood, the pending worldwide shortages, and the need for compatibility testing are the driving forces contributing towards the development of blood substitutes. The leading research is focusing on hemoglobin-based oxygen carriers (HBOCs), which are limited in clinical application due to the pressor effect they induce. In this study, the mechanisms through which HBOCs affect mean arterial pressure (MAP), arteriolar …

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Comparison Of Leukocyte Classes Most Likely To Cause Vascular Dysfunction In Preeclampsia, Kristen Anne Cadden Jan 2006

Comparison Of Leukocyte Classes Most Likely To Cause Vascular Dysfunction In Preeclampsia, Kristen Anne Cadden

Theses and Dissertations

Leukocytes are activated in women with preeclampsia, but the class of leukocyte most likely to cause vascular dysfunction is not known. We hypothesized that neutrophils may be the class of leukocyte most involved in causing this dysfunction because neutrophils are the most abundant of the leukocytes and their numbers increase during pregnancy. In this study we compared vascular infiltration of neutrophils (CD66b) with monocytes/macrophages (CD14) and lymphocytes (CD99) in normal non-pregnant women (NNP), normal pregnant women (NP), and preeclamptic women (PE). There was no significant difference in the infiltration of lymphocytes into the maternal vasculature in PE as compared to …

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Functional Consequences Of Matrix Metalloproteinase-1 Over-Expression In Human Gliomas, Emily Mullet Jan 2006

Functional Consequences Of Matrix Metalloproteinase-1 Over-Expression In Human Gliomas, Emily Mullet

Theses and Dissertations

Malignant brain tumors are among the deadliest of human cancers. Despit recent advancements in conventional therapies, glioblastomas remain incurable, largel y due to their ability to invade surrounding tissue. Matrix metalloproteinases are thought to contribute to the invaseive phenotype of human gliomas. Absent in normal brain, matrix metalloproteinase-1 (MMP-1) has been shown to be present in gliomas, and in particular in glioblastoma multiforme (GBM). To begin to examine the role of MMP-1 in these tumore, two human glioma cell lines were stably transfected with MMP-1 cDNA. Confirmation of MMP-1 over-expression in these cells was achieved through real-time PCR and Western …

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The Effect Of Adding Drag-Reducing Polymers To Resuscitation Fluid During Hemorrhagic Shock On Skeletal Muscle Microcirculation, Geoffrey C. Alexander Jan 2006

The Effect Of Adding Drag-Reducing Polymers To Resuscitation Fluid During Hemorrhagic Shock On Skeletal Muscle Microcirculation, Geoffrey C. Alexander

Theses and Dissertations

Previous studies have shown an increase in survival when a minute amount of drag-reducing polymers were added to a resuscitation fluid. The purpose of this investigation was to examine the effect of adding a minute amount of the drag-reducing polymer polyethylene glycol to a resuscitation fluid, on the microcirculation of skeletal muscle during a volume-controlled hemorrhage model. The spinotrapezius muscle in twelve male Sprague Dawley rats was exteriorized for microvascular measurements of the arterioles. The diameters of the three levels of arterioles, interstitial fluid PO2, and RBC velocity in the feed arteriole were measured. Flow in the feed arteriole was …

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Energy Value In Llamas (Lama Glama) Fed With Alfalfa Hay (Modicago Sativa) And Barley (Hordeum Vulgare) For Apparent Digestibility In Vivo In The National Camelid Germplasm Bank (Ceac), Edwin Gonzalo Ugarte Huanca Jan 2006

Energy Value In Llamas (Lama Glama) Fed With Alfalfa Hay (Modicago Sativa) And Barley (Hordeum Vulgare) For Apparent Digestibility In Vivo In The National Camelid Germplasm Bank (Ceac), Edwin Gonzalo Ugarte Huanca

Theses and Dissertations

In this experiment, we used four male llamas that were three to four years of age from the Khara race. They were divided into two ad libitum feeding groups. The digestible energy (ED) was determined using samples that were sent to the laboratory. These samples were derived from a conventional in vivo assay using the method of total fecal collection in order to determine the difference between energy consumed and energy excreted. Metabolizable energy was calculated by deducting digestible energy, energy loss in the urine and energy loss in the gases (methane). Urinary energy was determined through the measurement of …

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Effect Of Nitric Oxide On Oxygen Consumption Of Skeletal Muscle, Christina Lyn Cox Jan 2006

Effect Of Nitric Oxide On Oxygen Consumption Of Skeletal Muscle, Christina Lyn Cox

Theses and Dissertations

Mammalian cells require a continuous and sufficient supply of oxygen to carry out their functions. The oxygen pathway has an overall direction taking O2 from the air to the mitochondria, which is a result of the mitochondrial O2 consumption (VO2) NO various effects on the mitochondria: at low concentrations for short periods NO specifically and irreversibly inhibits cytochrome c and reversibly inhibits cytochrome c oxidase, to decrease VO2. Thus, NO can modulate VO2 of skeletal muscle. The purpose of the present study was to measure VO2 of the rat spinotrapezius muscle under conditions of altered NO. The methods used provide …

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Isolation Of Mesenchymal Stem Cells Derived From Adult Bone Marrow And Umbilical Cord Blood And Their Potential To Differentiate Into Osteoblasts, Andrew P. Pacitti Jan 2006

Isolation Of Mesenchymal Stem Cells Derived From Adult Bone Marrow And Umbilical Cord Blood And Their Potential To Differentiate Into Osteoblasts, Andrew P. Pacitti

Theses and Dissertations

The demand for treatment strategies of musculoskeletal tissues is continuously growing, especially considering the increasing number of elderly people with degenerative diseases of the skeletal system. Despite major strides in the field of bone regenerative medicine during the years, current therapies, such as bone grafts, still have several limitations. Multipotent stem cells, such as mesenchymal stem cells (MSCs) are promising candidates for tissue repair because of their differentiation potential and their capacity to undergo extensive replication. However, isolating a homogeneous population of MSCs from multiple sources is an area that needs to be addressed. Also, the knowledge regarding the mechanisms …

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Anatomical Bases For Auditory Projections To Suprasylvian Visual Areas In The Cat Cerebral Cortex, Giriaj K. Sharma Jan 2006

Anatomical Bases For Auditory Projections To Suprasylvian Visual Areas In The Cat Cerebral Cortex, Giriaj K. Sharma

Theses and Dissertations

How the neural representations of different sensory modalities transition from one to another is an unexplored issue of cortical organization. The present experiments addressed this problem by examining auditory projections to the lateral suprasylvian visual area (LSS) of the cat using neuroanatomical tract tracing methods. Injections of tracer (Biotinylated Dextran Amine, BDA) were made into defined areas of the cat auditory cortex. Following transport and tissue processing, a light microscope with a digitizing stage was used to visualize and plot labeled auditory projections to the LSS. The results showed that all auditory cortices tested demonstrated projections to a restricted portion …

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Early Mediators Of Cutaneous Ischemia Reperfusion Injury: A Mouse Model, Christopher Rogers Pruitt Jan 2006

Early Mediators Of Cutaneous Ischemia Reperfusion Injury: A Mouse Model, Christopher Rogers Pruitt

Theses and Dissertations

Chronic tissue injuries present an enormous problem to both patients and healthcare professionals, and yet little is definitively known as to the underlying pathophysiology. While there are numerous comorbidities associated with these wounds, a unifying theme has been proposed to be the repetitive incidence of ischemia reperfusion injury.A mouse model of cyclic ischemia reperfusion was employed to examine the initiation events in the pathology of chronic wounds. Mice were subjected to eight hours of magnetic skin compression via four cycles of two-hours ischemia and thirty minutes of reperfusion. The presence of neutrophil markers of oxidative stress and inflammation such as …

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Type-5 Phosphodiesterase Inhibition In The Prevention Of Doxorubicin Cardiomyopathy, Patrick William Fisher Jan 2005

Type-5 Phosphodiesterase Inhibition In The Prevention Of Doxorubicin Cardiomyopathy, Patrick William Fisher

Theses and Dissertations

Prior studies have demonstrated the effect of diazoxide in protecting against apoptosis via mitochondrial KATP channel opening in vitro. The current investigations are designed to determine if sildenafil, a phosphodiesterase-5 inhibitor and known mitochondrial KATP channel opener, would protect against chronic doxorubicin cardiomyopathy both in vivo and in vitro.Male ICR mice were randomized to 1 of 4 treatments: saline, sildenafil (0.7 mg/kg IP), doxorubicin (5 mg/kg IP), and sildenafil (0.7 mg/kg IP)+doxorubicin. Apoptosis was determined using the terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling and in situ oligo ligation methods. Desmin distribution was determined via immunofluorescence. Bcl-2 was analyzed by …

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Long-Term Cardioprotection With Phosphodiesterase-5 Inhibition Against Ischemia-Reperfusion Injury: Role Of Nitric Oxide., Vladimir Paul Daoud Jan 2005

Long-Term Cardioprotection With Phosphodiesterase-5 Inhibition Against Ischemia-Reperfusion Injury: Role Of Nitric Oxide., Vladimir Paul Daoud

Theses and Dissertations

Recent studies have shown that the potent phosphodiesterase-5 (PDE-5) inhibitor, sildenafil citrate, induces a powerful cardioprotective effect against ischemia-reperfusion (I/R) injury in rabbit and mouse hearts. However, the effect of this drug in inducing long-term protection against I/R injury remains unknown. The goal of this study was to identify the duration of the protective window of sildenafil citrate as well as vardenafil, a more potent PDE-5 inhibitor. Rabbits were treated with sildenafil (0.7 mg/kg, iv), vardenafil (0.143 mg/kg), or an equivalent volume of saline. After 24 hrs, 48 hrs, 96 hrs, or 7 days of sildenafil treatment, the hearts were …

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Novel Strategies In Cardioprotection Against Ischemia/Reperfusion Injury, Fadi N. Salloum Jan 2005

Novel Strategies In Cardioprotection Against Ischemia/Reperfusion Injury, Fadi N. Salloum

Theses and Dissertations

Cell damage represents a major pathomechanism in many diseases of high clinical interest, such as myocardial infarction (MI), where it plays an important role in ischemia-reperfusion (I/R) injury. Considerable progress has been made towards identifying physiological and pharmacological agents that play a key role in myocardial preconditioning against I/R injury and also elucidating the molecular changes leading to such protection.Second messengers in cellular signaling pathways, such as cGMP have been well implicated as key players in ischemic and pharmacological preconditioning (PC) of the heart. Phosphodiesterase type 5 (PDE-5) is an enzyme that specifically hydrolyzes cGMP thereby decreasing its tissue concentration. …

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The Effect Of Red Blood Cell Velocity On Oxygenation Measurements Using Resonance Raman Spectroscopy, Derrick Williams Jan 2005

The Effect Of Red Blood Cell Velocity On Oxygenation Measurements Using Resonance Raman Spectroscopy, Derrick Williams

Theses and Dissertations

Resonance Raman spectroscopy can be used to estimate the hemoglobin oxygen saturation. Previous studies have demonstrated that exposure of oxygenated red blood cells to laser illumination may result in photo-induced displacement of oxygen from hemoglobin. In this study, an in vitro model was used to evaluate the relationship between this photo-induced effect and the red blood cell velocity. A computer-controlled system was implemented to acquire variables such as red cell velocity, microvessel diameter and hemoglobin oxygen saturation at multiple sites in selected microvascular networks. Using this system, resonance Raman spectroscopy was employed to measure hemoglobin oxygen saturation gradients in arterioles …

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Acute And Chronic Effects Of Artificial Rearing On Rat Genioglossus Muscle, Wayne Allen Moore Jr. Jan 2005

Acute And Chronic Effects Of Artificial Rearing On Rat Genioglossus Muscle, Wayne Allen Moore Jr.

Theses and Dissertations

In most mammals, nutritive suckling is critical during the early neonatal period. The genioglossus (GG) muscle in rat plays an important role in protruding the tongue for efficient suckling. The purpose of this study was to examine the contractile properties and myosin heavy chain (MHC) phenotype of the GG following an early period of artificial rearing, which reduced nutritive suckling. Beginning at three days of age Sprague-Dawley rats were fed via implanted gastric cannula until postnatal day 14 (P14). At P14, artificially reared (AR) rat pups were either placed with a lactating dam until the end of the weaning period …

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Erythrocyte-Associated Transients In Capillary Po2 In The Rat Spinotrapezius Muscle During Hemodilution With Hespan And A Hemoglobin-Based Oxygen Carrier, Matthew Barker Jan 2005

Erythrocyte-Associated Transients In Capillary Po2 In The Rat Spinotrapezius Muscle During Hemodilution With Hespan And A Hemoglobin-Based Oxygen Carrier, Matthew Barker

Theses and Dissertations

Hemoglobin-based oxygen carriers for use as transfusion fluids have emerged as a leading technology directed at stemming shortages of a safe blood supply and providing a readily available resuscitation fluid in various trauma situations. The purpose of this investigation was to determine the effects of isovolemic hemodilution with Hespan and a hemoglobin-based oxygen carrier (HBOC) on erythrocyte-associated transients (EATs) in capillary PO2. The particulate nature of blood flow in capillaries, when observed from a stationary observation point, results in fluctuations of PO2 as alternating red blood cells and plasma gaps move through the detection region. Therefore, through experimental methods which …

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Phosphorylation Of Skeletal Muscle Acetyl-Coa Carboxylase By Ampk Enhances Palmitoyl-Coa Inhibition, Dustin S. Rubink Dec 2004

Phosphorylation Of Skeletal Muscle Acetyl-Coa Carboxylase By Ampk Enhances Palmitoyl-Coa Inhibition, Dustin S. Rubink

Theses and Dissertations

Acetyl-CoA carboxylase (ACC) catalyzes the formation of malnoyl-CoA, which in turn controls the rate of fatty acid metabolism. ACC beta or 2 has been shown to be localized on the mitochondria in close proximity to carnintine palmitoyl transferase 1 (CPT-1), the enzyme responsible for the influx of acyl-CoA into the matrix where beta oxidation takes place. CPT-1 is inhibited by malonyl-CoA produced by ACC. It has been well documented that AMP activated kinase (AMPK) when activated phosphorylates and inactivates ACC. ACC is controlled allosterically by citrate, which activates, and by palmitoyl-COA, which inhibits. In this study, we asked the question, …

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Mechanism Governing The Cellular Susceptibility To Secretory Phospholipase A2, Lauren Blackburn Jensen Jun 2004

Mechanism Governing The Cellular Susceptibility To Secretory Phospholipase A2, Lauren Blackburn Jensen

Theses and Dissertations

Secretory phospholipase A2 (sPLA2) is an important part of apoptosis and disposal of damaged and dying cells. However, healthy cells are not susceptible to attack by sPLA2. Recent studies have focused on membrane properties necessary to induce susceptibility in both artificial and biological membranes. Hydrolysis of phospholipids by sPLA2 requires at least two preliminary steps: first, adsorption of the enzyme to the cellular membrane, and second, movement of a phospholipid into the active site of the enzyme. We determined the effects of susceptibility on each of the two steps and determined the contributions changing the equilibrium constants have on susceptibility. …

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Effects Of Emphysema And Chronic Hypoxemia On Skeletal Muscle Oxygen Supply And Demand, John D. Lowman Jr. Jan 2004

Effects Of Emphysema And Chronic Hypoxemia On Skeletal Muscle Oxygen Supply And Demand, John D. Lowman Jr.

Theses and Dissertations

Skeletal muscle dysfunction in chronic obstructive pulmonary disease (COPD) is a condition in which peripheral skeletal muscle undergoes myopathic changes which impair muscle function, limit physical performance, and can lead to significant disability. While the etiology of the dysfunction is unknown, this study was conducted to test the hypothesis that chronic hypoxemia leads to alterations in oxygen transport and muscle function. A primary objective was to validate elastase-induced emphysema in rats as an animal model of skeletal muscle dysfunction in COPD.Arterial blood gases were used to determine the severity of hypoxemia and sodium dodecyl sulfate- polyacrylamide gel electrophoresis was used …

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Implementation And Validation Of A Real-Time Wireless Non-Invasive Physiological Monitoring In A High-G Environment, H. Aydin Akcivi Mar 2003

Implementation And Validation Of A Real-Time Wireless Non-Invasive Physiological Monitoring In A High-G Environment, H. Aydin Akcivi

Theses and Dissertations

The overall purpose of this research is to develop a system capable of real-time personal positioning and physiological monitoring. The system will be composed of a shirt having non-invasive physiological sensors, Global Positioning System (GPS) receiver, wireless data transceiver, and real-time PC-based control station. The specific purpose of this research phase was to determine the performance capabilities of a modified LifeShirt™ alone (without GPS) in a high gravitational force environment with the data being sent wirelessly in real-time. The LifeShirt™ was modified with a real time wireless transmission system.

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Vascular Cell Dysfunction And Transendothelial Migration Of Neutrophils In Preeclampsia, Courtney Elizabeth Leik Jan 2003

Vascular Cell Dysfunction And Transendothelial Migration Of Neutrophils In Preeclampsia, Courtney Elizabeth Leik

Theses and Dissertations

Oxidative stress, hyperlipidemia, neutrophil activation and endothelial cell dysfunction are characteristic of women with preeclampsia. We used in vitro experiments to test if a combination of oxidative stress and linoleic acid favors a mechanism for neutrophil transendothelial migration. We used linoleic acid because it is one of the fatty acids elevated in preeclampsia and the precursor for arachidonic acid and its inflammatory metabolites. For these studies, we developed a methodology for isolating and Culturing human vascular smooth muscle cells from placental chorionic plate arteries. Treatment of these cells with an oxidizing solution enriched with linoleic acid, but neither component alone, …

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Pilot Mental Workload Calibration, Jeremy B. Noel Mar 2001

Pilot Mental Workload Calibration, Jeremy B. Noel

Theses and Dissertations

Predicting high pilot mental workload is important to the U.S. Air Force because lives and aircraft can be lost when errors are made during periods of mental overload and task saturation. Current research efforts use psychophysiological measures such as electroencephalography, cardiac, ocular, and respiration measures in an attempt to identify and predict mental workload levels. The primary focus of this effort is the development of a calibration scheme that allows a small subset of salient psychophysiological features developed using actual flight data for one pilot on a given day to accurately classify pilot mental workload for a separate pilot on …

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Functional Characterization Of Mitogen-Dependent And Self-Perpetuating Nb2 Lymphoma Cell Lines, Charlotte Cockrell Jan 2000

Functional Characterization Of Mitogen-Dependent And Self-Perpetuating Nb2 Lymphoma Cell Lines, Charlotte Cockrell

Theses and Dissertations

This investigation involved the functional characterization of four Nb2 sub lines (Nb2-U- 17, Nb2-l l , SFJCD l , and D5) for their mitogenic and apoptotic responses to DEX ± PRL treatment. Many protein factors have been implicated to be crucial in controlling the apoptotic and mitogenic pathways. In conjunction with functional studies, an immunocytochemical investigation of four protein signals (NFKB, IKBa, STAT 5b, and the GR) was undertaken in an attempt to establish a relationship between the functional responsiveness of a given cell line and the concentration of a particular protein marker. Comparison of the functional data obtained for …

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Examination Of Signals Involved In Dexamethasone Induced Apoptosis In Nb2 Lymphoma Cells, Suhas Badarinath Jan 1999

Examination Of Signals Involved In Dexamethasone Induced Apoptosis In Nb2 Lymphoma Cells, Suhas Badarinath

Theses and Dissertations

Consistent with previous studies, we demonstrated that dexamethasone (Dex) caused cytolysis/apoptosis in log phase Nb2 lymphoma cells, while prolactin (Prl) inhibited this effect. The Nb2 model was used to investigate the mechanisms of apoptosis control with the aid of immunocytochemistry (ICC). We established with absorption the specificity of staining due to Fas, Fas Ligand, Bcl-2, and Bax antibodies (the specificity of anti-p53 could not be verified). Dex-induced cytolysis/apoptosis was detected in synchronized (G⁰/G¹) cells after 6 and 8 hours of Dex exposure. A novel, computerized technique was used to quantitate the proportion of cells immunostained for the signals of interest …

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Correlation Of Visualized Glucocorticoid Receptor And Apoptosis In Individual Clones Of Nb2 Cells, Devang M. Patel Jan 1999

Correlation Of Visualized Glucocorticoid Receptor And Apoptosis In Individual Clones Of Nb2 Cells, Devang M. Patel

Theses and Dissertations

The Nb2 lymphoma cell line is susceptible to glucocorticoid (GC)-induced apoptosis in the absence of mitogen and this effect is inhibited by the mitogen prolactin (PRL). This process is believed to be mediated by the glucocorticoid receptor (GR) and various downstream signals. The purpose of this study was to use the limiting dilution method to isolate subsets of Nb2 clones which expressed either highly enriched amounts of GR or an absence of GR and to relate the amount of GR to the magnitude of GC induced cytolysis. The presence of GR in these clones was determined by immunocytochemistry (ICC) using …

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Immunocytochemical Study Of Apoptosis Signaling In Nb2 Lymphoma Cells, Angelo P. Guanzon Jan 1998

Immunocytochemical Study Of Apoptosis Signaling In Nb2 Lymphoma Cells, Angelo P. Guanzon

Theses and Dissertations

In the absence of mitogen, administration of Dexamethasone (Dex) induces apoptosis, or programmed-cell death in the Nb2 lymphoma cell. Addition of prolactin (Prl), on the other hand, blocks this effect. As a model for apoptosis, we were able to investigate this Dex-Prl interaction by means of a morphological approach: one that could be visualized under a light microscope. This approach allowed us to achieve several aims. First, we were able to develop a method of cell quantification befitting a morphological study based upon the hemacytometer. Second, with Trypan Blue exclusion, we were able to verify Dex/Prl-responsiveness in the Nb2 cells. …

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Electrophysiological Effects Of Lysoplasmenylcholine On Rabbit Ventricular Myocytes, Ray Caldwell Jan 1997

Electrophysiological Effects Of Lysoplasmenylcholine On Rabbit Ventricular Myocytes, Ray Caldwell

Theses and Dissertations

Myocardial ischemia activates a phospholipase A2 that targets plasmalogen phospholipids and liberates 1-0-alkenyl-Iysoplasmenylcholine (LPLC) in preference to 1-0- acyl-Iysophosphatidylcholine (LPC). Although LPC is a pro arrhythmic ischemic metabolite, the effect of LPLC on cardiac electrophysiology is unknown. At the lowest doses investigated, LPLC induced spontaneous contractions in otherwise quiescent rabbit ventricular myocytes significantly faster than LPC. Spontaneous contractions developed with median times of 16.4 (n = 64), 27.4 (n = 36), and >60 min (n = 25) during exposure to 5, 2.5, and 1 JlM LPLC compared with 38.0 (n = 48) and >60 min (n = 29) for 5 …

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Spatial And Temporal Mechanisms Of Spinal Nociceptive Coding, Robert C. Coghill Jan 1991

Spatial And Temporal Mechanisms Of Spinal Nociceptive Coding, Robert C. Coghill

Theses and Dissertations

In order to better characterize spatial and temporal mechanisms of nociceptive processing in the central nervous system (CNS), the responses of rat spinal cord neuron populations to prolonged painful stimuli were examined. Metabolic mapping studies revealed that prolonged nociceptive thermal stimuli produced extensive activation in the deep dorsal horn, but minimal activation in the superficial dorsal horn. Electrophysiological investigations of neurons within these regions revealed that the responses of wide dynamic range (WDR) neurons, the predominate nociceptive neuron in the deep dorsal horn, did not habituate substantially to prolonged nociceptive stimuli. In contrast, the responses of nociceptive specific neurons, the …

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