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Full-Text Articles in Medicine and Health Sciences

Contrast Adaptation In The Lateral Eye Of Limulus Polyphemus, Tchoudomira Valtcheva Nov 2013

Contrast Adaptation In The Lateral Eye Of Limulus Polyphemus, Tchoudomira Valtcheva

USF Tampa Graduate Theses and Dissertations

Luminance and contrast adaptation are neuronal mechanisms that the retina applies for continuous adjustment to light sensitivity though a collection of cellular and synaptic mechanisms distributed across the retinal network, thus accommodating the wide input range of the visual system within the constricted output range of retinal ganglion cells. Luminance mean adaptation has been demonstrated in the output neurons of the invertebrate eye (eccentric cells), and the aim of the study was to investigate whether the homology in visual processing extends to luminance variance (contrast) adaptation as well. The spike trains of individual eccentric cells were recorded from live horseshoe …


Proteolytic Processing Of The Amyloid Precursor Protein During Apoptosis And Cell Cycle: Implications For Alzheimer's Disease, Tina N. Fiorelli Jan 2013

Proteolytic Processing Of The Amyloid Precursor Protein During Apoptosis And Cell Cycle: Implications For Alzheimer's Disease, Tina N. Fiorelli

USF Tampa Graduate Theses and Dissertations

Alzheimer's disease is characterized by the presence of amyloid plaques, made up primarily of Aϐ peptides, and neurofibrillary tangles, containing hyperphosphorylated tau. Aϐ is generated by sequential proteolysis of the amyloid precursor protein (APP) by beta and gamma secretases. The leading hypothesis of Alzheimer's disease pathogenesis is the amyloid cascade hypothesis, which suggests that amyloid is central to the disease process. However, tau pathology correlates more closely with cognitive dysfunction and follows a predictable anatomical course through the brain. We hypothesize that if Aϐ is upstream of tau pathology and tau pathology follows this predictable course through the brain, Aϐ …


The Role Of Molecular Chaperones In The Etiology And Treatment Of Psychiatric Diseases In The Elderly, John Clarence O'Leary Jan 2013

The Role Of Molecular Chaperones In The Etiology And Treatment Of Psychiatric Diseases In The Elderly, John Clarence O'Leary

USF Tampa Graduate Theses and Dissertations

The elderly are at increased risk for developing psychiatric diseases, which include Alzheimer's disease, depression, anxiety and suicide. The probability of multiple disease comorbidity is also increased in the elderly. At the cellular level, the loss of protein homeostasis is often at the root of disease emergence, and thus the scientific community is searching for ways to help maintain this balance. A vast group of proteins that are paramount to balancing and counterbalancing protein levels is the molecular chaperone protein group, which has evolved a tremendous variety of functions in the cell. They aid in protein trafficking, folding, receptor signaling, …


Diet-Induced Ketosis And Calorie Restriction In Mouse Models Of Alzheimer's Pathology, Milene Lara Brownlow Jan 2013

Diet-Induced Ketosis And Calorie Restriction In Mouse Models Of Alzheimer's Pathology, Milene Lara Brownlow

USF Tampa Graduate Theses and Dissertations

Dietary manipulations and their pharmacological outcomes have been increasingly studied in neurodegenerative diseases. However, a systematic comparison among different methods in validated animal models of Alzheimer's disease is made necessary due to several different approaches applied in recent studies. Moreover, despite the large body of evidence on the effects of calorie restriction (CR) and ketogenic diets (KDs) on amyloid pathology, no consistent data is available on the effects of calorie restriction, ketogenic diet or ketone supplements on tau pathology in transgenic models of AD. Moreover, the ketogenic diet used in our studies was custom made with low carbohydrate content and …


Molecular And Cellular Mechanisms Of Reelin Signaling In The Adult Hippocampus, Justin Howard Trotter Jan 2013

Molecular And Cellular Mechanisms Of Reelin Signaling In The Adult Hippocampus, Justin Howard Trotter

USF Tampa Graduate Theses and Dissertations

The Reelin signaling pathway is critical for neuronal migration during development and the function of excitatory synapses in the adult forebrain. Despite a growing body of evidence implicating impaired Reelin signaling in the pathogenesis of numerous neuropsychiatric and neurodegenerative disorders, including Schizophrenia and Alzheimer's disease, little is known still regarding the specific molecular and cellular mechanisms whereby Reelin signaling modulates the function of synapses to enable normal learning and memory. In this dissertation, we addressed these knowledge gaps by identifying mechanisms of Reelin proteolysis following synaptic potentiation (Chapter 2) and dissociated the synaptic function of Reelin signaling at excitatory (Chapter …


The Inflammatory Response Initiated By The Spleen To Ischemic Stroke, Hilary Seifert Jan 2013

The Inflammatory Response Initiated By The Spleen To Ischemic Stroke, Hilary Seifert

USF Tampa Graduate Theses and Dissertations

The peripheral immune system plays a role in delayed neural injury after stroke. This response originates from the spleen as splenectomy prior to middle cerebral artery occlusion (MCAO) in rats significantly reduces infarct volume in the brain. This research is based on the hypothesis that inhibiting the splenic response will reduce neurodegeneration after stroke. Studies in animals have implicated lymphocytes as the immune cell type that is detrimental following MCAO. Interferon gamma (IFNγ) has been identified as a pro-inflammatory cytokine that is also detrimental following stroke. IFNγ is important because it activates microglia and macrophages in a pro-inflammatory nature that …


Design, Manufacturing, And Assembly Of A Flexible Thermoelectric Device, Christopher Anthony Martinez Jan 2013

Design, Manufacturing, And Assembly Of A Flexible Thermoelectric Device, Christopher Anthony Martinez

USF Tampa Graduate Theses and Dissertations

This thesis documents the design, manufacturing, and assembly of a flexible thermoelectric device. Such a device has immediate use in haptics, medical, and athletic applications. The governing theory behind the device is explained and a one dimensional heat transfer model is developed to estimate performance. This model and consideration for the manufacturing and assembly possibilities are the drivers behind the decisions made in design choices. Once the design was finalized, manufacturing methods for the various components were explored. The system was created by etching copper patterns on a copper/polyimide laminate and screen printing solder paste onto the circuits. Thermoelectric elements …


The Effects Of Temporal Preparation On Reaction Time, Glen Robert Forester Jan 2013

The Effects Of Temporal Preparation On Reaction Time, Glen Robert Forester

USF Tampa Graduate Theses and Dissertations

When responding to external stimuli, preparation reduces Reaction Time (RT). One form of preparation known as temporal preparation results from advance knowledge about when a stimulus will appear. We used Event Related Potentials to investigate how increasing temporal preparation decreases RT during a speeded, choice RT task by manipulating temporal preparation within subjects. In order to determine which cognitive processes are speeded, the latencies of the Lateralized Readiness Potential (LRP) and P300 were examined across two levels of temporal preparation. In line with previous research the stimulus locked LRP, but not the response locked LRP, was speeded when temporal preparation …