174 research outputs found

    An Acid Alkylation of 8-Hydroxyquinoline

    Get PDF
    A thesis presented to the faculty of the School of Science and Mathematics at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by James D. Searcy on May 11, 1972

    Hydrology of small drainage areas

    Get PDF
    Realizing the need for data on small drainage areas the Missouri Highway Commission in 1947 began a cooperative project with the Water Resources Division of the United States Geological Survey which includes the establishment of small area gaging stations and recording rain gages. The purpose of this investigation is to study some of the data collected in the few years of operation of these small area stations with the aim of testing some of the hydrologic tools useful in the study of larger drainage basins to determine their applicability on small drainage basins. The relationship between the runoff of large and small drainage basins will be studied to learn how the data collected on the larger drainage basins may be used in the study of small areas. Although the records to be used in this study are too short for the purpose, it is hoped that some facts will be learned which will have application when longer term records become available for study --Introduction, pages 4-5

    LIPID SIGNALING IN BRAIN AGING AND ALZHEIMER\u27S DISEASE: PHARMACOLOGICALLY TARGETING CHOLESTEROL SYNTHESIS, TRANSPORT AND METABOLISM

    Get PDF
    The role cholesterol plays in the brain has long been underappreciated even though the brain contains a disproportionately high percentage of body cholesterol. Recent studies have found a link between the dysregulation of lipid metabolism and the risk of acquiring Alzheimer’s disease (AD) as well as a predisposition to cognitive decline. The goal of these studies was to elucidate the possible role lipid metabolism plays in pathological and normal brain aging by pharmacologically manipulating lipid metabolism and determining effects on key hippocampal biomarkers of AD and age-related cognitive decline. One series of experiments used an agonist (TO901317) to the liver X receptor (LXR) in two transgenic AD mouse models. Chronic LXR activation reduced AD associated pathology and improved cognitive performance in AD mouse models. However, long-term potentiation (LTP) was not enhanced and peripheral side effects were observed. In another series of experiments the effects of chronically inhibiting cholesterol synthesis on cognitive aging in rats was determined. Animals were treated with either of two commonly prescribed statins, simvastatin or atorvastatin. Simvastatin, the more lipophilic statin, increased LTP and reduced the duration of the afterhyperpolarization (AHP). In addition, simvastatin upregulated key genes of the cholesterol synthesis pathway in the hippocampus as revealed by microarray analyses, but was associated with impaired performance in the Morris Water Maze, a hippocampal dependent task. Atorvastatin, a less lipophilic statin, reduced the AHP, but did not affect LTP or cognitive performance. Atorvastatin modulated a very different set of genes and reduced brain cholesterol more than simvastatin. These results suggest that manipulation of cholesterol metabolism selectively modulates key aspects of AD and brain aging

    Chronic cerebral hypoperfusion alters amyloid-β peptide pools leading to cerebral amyloid angiopathy, microinfarcts and hemorrhages in Tg-SwDI mice

    Get PDF
    Cerebral hypoperfusion is an early feature of Alzheimer’s disease (AD) that influences the progression from mild cognitive impairment to dementia. Understanding the mechanism is of critical importance in the search for new effective therapies. We hypothesized that cerebral hypoperfusion promotes the accumulation of amyloid-β (Aβ) and degenerative changes in the brain and is a potential mechanism contributing to development of dementia. To address this, we studied the effects of chronic cerebral hypoperfusion induced by bilateral carotid artery stenosis on Aβ peptide pools in a transgenic mouse model of AD (transgenic mice with Swedish, Dutch and Iowa mutations in human amyloid precursor protein (APP) (Tg-SwDI)). Cerebrovascular integrity was characterized by quantifying the occurrence of microinfarcts and haemorrhages and compared with wild-type mice without Aβ. A significant increase in soluble Aβ peptides (Aβ40/42) was detected after 1 month of hypoperfusion in the parenchyma in parallel with elevated APP and APP proteolytic products. Following 3 months, a significant increase in insoluble Aβ40/42 was determined in the parenchyma and vasculature. Microinfarct load was significantly increased in the Tg-SwDI as compared with wild-type mice and further exacerbated by hypoperfusion at 1 and 3 months. In addition, the number of Tg-SwDI hypoperfused mice with haemorrhages was increased compared with hypoperfused wild-type mice. Soluble parenchymal Aβ was associated with elevated NADPH oxidase-2 (NOX2) which was exacerbated by 1-month hypoperfusion. We suggest that in response to hypoperfusion, increased Aβ production/deposition may contribute to degenerative processes by triggering oxidative stress promoting cerebrovascular disruption and the development of microinfarcts.</jats:p

    Deep Sleep and Parietal Cortex Gene Expression Changes Are Related to Cognitive Deficits with Age

    Get PDF
    BACKGROUND: Age-related cognitive deficits negatively affect quality of life and can presage serious neurodegenerative disorders. Despite sleep disruption\u27s well-recognized negative influence on cognition, and its prevalence with age, surprisingly few studies have tested sleep\u27s relationship to cognitive aging. METHODOLOGY: We measured sleep stages in young adult and aged F344 rats during inactive (enhanced sleep) and active (enhanced wake) periods. Animals were behaviorally characterized on the Morris water maze and gene expression profiles of their parietal cortices were taken. PRINCIPAL FINDINGS: Water maze performance was impaired, and inactive period deep sleep was decreased with age. However, increased deep sleep during the active period was most strongly correlated to maze performance. Transcriptional profiles were strongly associated with behavior and age, and were validated against prior studies. Bioinformatic analysis revealed increased translation and decreased myelin/neuronal pathways. CONCLUSIONS: The F344 rat appears to serve as a reasonable model for some common sleep architecture and cognitive changes seen with age in humans, including the cognitively disrupting influence of active period deep sleep. Microarray analysis suggests that the processes engaged by this sleep are consistent with its function. Thus, active period deep sleep appears temporally misaligned but mechanistically intact, leading to the following: first, aged brain tissue appears capable of generating the slow waves necessary for deep sleep, albeit at a weaker intensity than in young. Second, this activity, presented during the active period, seems disruptive rather than beneficial to cognition. Third, this active period deep sleep may be a cognitively pathologic attempt to recover age-related loss of inactive period deep sleep. Finally, therapeutic strategies aimed at reducing active period deep sleep (e.g., by promoting active period wakefulness and/or inactive period deep sleep) may be highly relevant to cognitive function in the aging community

    Effects of Long-Term Pioglitazone Treatment on Peripheral and Central Markers of Aging

    Get PDF
    BACKGROUND: Thiazolidinediones (TZDs) activate peroxisome proliferator-activated receptor gamma (PPARgamma) and are used clinically to help restore peripheral insulin sensitivity in Type 2 diabetes (T2DM). Interestingly, long-term treatment of mouse models of Alzheimer\u27s disease (AD) with TZDs also has been shown to reduce several well-established brain biomarkers of AD including inflammation, oxidative stress and Abeta accumulation. While TZD\u27s actions in AD models help to elucidate the mechanisms underlying their potentially beneficial effects in AD patients, little is known about the functional consequences of TZDs in animal models of normal aging. Because aging is a common risk factor for both AD and T2DM, we investigated whether the TZD, pioglitazone could alter brain aging under non-pathological conditions. METHODS AND FINDINGS: We used the F344 rat model of aging, and monitored behavioral, electrophysiological, and molecular variables to assess the effects of pioglitazone (PIO-Actos® a TZD) on several peripheral (blood and liver) and central (hippocampal) biomarkers of aging. Starting at 3 months or 17 months of age, male rats were treated for 4-5 months with either a control or a PIO-containing diet (final dose approximately 2.3 mg/kg body weight/day). A significant reduction in the Ca2+-dependent afterhyperpolarization was seen in the aged animals, with no significant change in long-term potentiation maintenance or learning and memory performance. Blood insulin levels were unchanged with age, but significantly reduced by PIO. Finally, a combination of microarray analyses on hippocampal tissue and serum-based multiplex cytokine assays revealed that age-dependent inflammatory increases were not reversed by PIO. CONCLUSIONS: While current research efforts continue to identify the underlying processes responsible for the progressive decline in cognitive function seen during normal aging, available medical treatments are still very limited. Because TZDs have been shown to have benefits in age-related conditions such as T2DM and AD, our study was aimed at elucidating PIO\u27s potentially beneficial actions in normal aging. Using a clinically-relevant dose and delivery method, long-term PIO treatment was able to blunt several indices of aging but apparently affected neither age-related cognitive decline nor peripheral/central age-related increases in inflammatory signaling

    Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector

    Get PDF
    The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry
    corecore