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Full-Text Articles in Life Sciences

Fgf4 Induced Wnt5a Gradient In The Limb Bud Mediates Mesenchymal Cell Directed Migration And Division, John C. Allen Dec 2013

Fgf4 Induced Wnt5a Gradient In The Limb Bud Mediates Mesenchymal Cell Directed Migration And Division, John C. Allen

Theses and Dissertations

The AER has a vital role in directing embryonic limb development. Several models have been developed that attempt to explain how the AER directs limb development, but none of them are fully supported by existing data. I provide evidence that FGFs secreted from the AER induce a gradient of Wnt5a. I also demonstrate that limb mesenchyme grows toward increasing concentrations of Wnt5a. We hypothesize that the changing shape of the AER is critical for patterning the limb along the proximal to distal axis. To better understand the pathway through which Wnt5a elicits its effects, we have performed various genetic studies. …


Endocannabinoid-Dependent Long-Term Depression Of Ventral Tegmental Area Gaba Neurons, Jared Mark Weed Dec 2013

Endocannabinoid-Dependent Long-Term Depression Of Ventral Tegmental Area Gaba Neurons, Jared Mark Weed

Theses and Dissertations

GABA neurons in the ventral tegmental area of the midbrain are important components in the brain's reward circuit. Long term changes in this circuit occur through the process of synaptic plasticity. It has been shown that high frequency stimulation, as well as treatment with endocannabinoids, can cause GABA neurons in the ventral tegmental area to undergo long term depression, a form of synaptic plasticity that decreases excitability of cells. The present study elaborates on the mechanism whereby high frequency stimulation can result in long term depression of ventral tegmental area GABA neurons. Using the whole cell patch clamp technique in …


Involvement Of Ampk And Ap-1 Biochemical Pathways In Il-6 Regulation Of Steroidogenic Enzymes In The Adrenal Cortex, Matharage Shenali De Silva Dec 2013

Involvement Of Ampk And Ap-1 Biochemical Pathways In Il-6 Regulation Of Steroidogenic Enzymes In The Adrenal Cortex, Matharage Shenali De Silva

Theses and Dissertations

The adrenal cortex is a crucial endocrine gland in the mammalian stress response. In chronic inflammatory stress, cortisol is elevated whereas adrenal androgens are decreased. Furthermore, ACTH levels have poor correlation with the plasma cortisol in these conditions, thus suggesting that other factors are driving the stress response during chronic inflammatory stress. Interleukin-6 (IL-6), a cytokine which is released during chronic inflammatory stress, is assumed to be one such factor. Thus the biochemical pathways by which IL-6 increases cortisol release from the zona fasciculata (ZF), and decreases adrenal androgen release from the zona reticularis (ZR) were investigated. Since IL-6 activates …


Beta-Amyloid Inhibition Of Alpha 7 Nicotinic Acetylcholine Receptors And Factors That Potentially Influence The Aî²/Nachr Interaction, Christopher L. Jacobsen Jul 2013

Beta-Amyloid Inhibition Of Alpha 7 Nicotinic Acetylcholine Receptors And Factors That Potentially Influence The Aî²/Nachr Interaction, Christopher L. Jacobsen

Theses and Dissertations

Alzheimer's disease (AD) is a neurodegenerative disorder that manifests in the form of deficiencies in cognitive processes such as memory and learning. The pathological features of AD include hyperphosphorylated tau proteins that form neurofibrillary tangles as well as senile plaques composed primarily of the peptide β-amyloid (Aβ). When present in high concentrations in the brain, Aβ inhibits certain subtypes of neuronal nicotinic acetylcholine receptors (nAChRs) in the hippocampus. The effects of Aβ in the hippocampus have proven to be neurotoxic, resulting in reduced functionality of nAChRs and the subsequent death of neurons in the cholinergic pathway. The early stages of …


Susceptibility Of Apoptotic Cells To Hydrolysis By Spla2: Molecular Basis And Mechanisms Defined, Elizabeth Gibbons Jul 2013

Susceptibility Of Apoptotic Cells To Hydrolysis By Spla2: Molecular Basis And Mechanisms Defined, Elizabeth Gibbons

Theses and Dissertations

Secretory phospholipase A2 hydrolyzes phospholipids at a lipid-water interface, resulting in pro-inflammatory products being released from cell membranes. Healthy cells are resistant to cleavage by this enzyme, but apoptotic cells become susceptible to its activity. Only bilayers with certain characteristics are able to be hydrolyzed. Most recently, studies in this lab have emphasized the idea that the biophysical state of the bilayer (in terms of lipid order, spacing, and fluidity) is relevant in determining the probability of one phospholipid escaping the membrane to be hydrolyzed. Prior to this study, it had been shown that apoptotic cells undergo biophysical alterations that …


A Model For Sensory Neuron Development By Fgf And Notch: A Multifactorial Approach, Jacob Eugene Voelkel Jun 2013

A Model For Sensory Neuron Development By Fgf And Notch: A Multifactorial Approach, Jacob Eugene Voelkel

Theses and Dissertations

The ophthalmic trigeminal placode (opV) exclusively gives rise to sensory neurons. A number of signaling pathways including Wnt, PDGF, FGF, and Notch are all involved in the progression of an undifferentiated cell in the opV placode to a proneural cell in the condensing opV ganglion. However, the regulatory relationships between these signal transduction pathways are still unknown. To determine if FGF activation acts to modulate Notch signaling in the sensory neurogenesis pathway, a novel multifactorial approach was employed: FGF signaling was inhibited in individual cells and globally with simultaneous inactivation of Notch signaling in chick embryos to investigate if FGF …