University of Kentucky

About: University of Kentucky is a education organization based out in Lexington, Kentucky, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 43933 authors who have published 92195 publications receiving 3256087 citations. The organization is also known as: UK.

Proteomic identification of nitrated proteins in Alzheimer's disease brain.

Abstract: Nitration of tyrosine in biological conditions represents a pathological event that is associated with several neurodegenerative diseases, such as amyotrophic lateral sclerosis, Parkinson’s disease and Alzheimer’s disease (AD). Increased levels of nitrated proteins have been reported in AD brain and CSF, demonstrating the potential involvement of reactive nitrogen species (RNS) in neurodegeneration associated with this disease. Reaction of NO with O � : 2 leads to formation of peroxynitrite ONOO – , which following protonation, generates cytotoxic species that oxidize and nitrate proteins. Several findings suggest an important role of protein nitration in modulating the activity of key enzymes in neurodegenerative disorders, although extensive studies on specific targets of protein nitration in disease are still missing. The present investigation represents a further step in understanding the relationship between oxidative modification of protein and neuronal death in AD. We previously applied a proteomics approach to determine specific targets of protein oxidation in AD brain, by successfully coupling immunochemical detection of protein carbonyls with two-dimensional polyacrylamide gel electrophoresis and mass spectrometry analysis. In the present study, we extend our investigation of protein oxidative modification in AD brain to targets of protein nitration. The identification of six targets of protein nitration in AD brain provides evidence to the importance of oxidative stress in the progression of this dementing disease and

Vibration Modulus of Normally Consolidated Clay

Abstract: The resonant-column technique was used to measure the vibration shear modulus of a normally consolidated kaolinite under various anisotropic states of stress. The effects of the deviatoric and isotropic components of stress, void ratio, and other secondary effects are studied. Data from these tests along with other previously published test results for other clays with different structures lead to the following conclusions: (1) The vibration shear modulus is independent of the deviatoric component of ambient stress (octahedral shear stress); (2) the vibration shear modulus decreases with increasing void ratio and Eq. 4 in the paper is a fair representation of the effect of void ratio; the effects of structure seem to be mostly accounted for by the void ratio parameter; (3) considering the isotropic component of ambient effective stress (effective octahedral normal stress), σ¯ 0 , as an independent variable, and not including the effects of void ratio and secondary time effects, the vibration shear modulus varies with σ¯ 0 to the 0.5 power; and (4) there is a secondary increase of the vibration shear modulus with time, at constant effective stress, not accounted for by changes in void ratio. This stiffness build-up is sensitive to particle disturbance and can be partially or totally destroyed by changes in effective stress. This effect may be quite important for soils in situ.

Meta-analysis: synthesizing research findings in ecology and evolution

Abstract: The growing number of empirical studies performed in ecology and evolution creates a need for quantitative summaries of research domains to generate higher-order conclusions about general trends and patterns. Recent developments In meta-analysis (the area of statistics that is designed for summarizing and analyzing multiple independent studies) have opened up new and exciting possibilities. Unlike more traditional qualitative and narrative reviews, meta-analysis allows powerful quantitative analyses of the magnitude of effects and has a high degree of objectivity because it is based on a standardized set of statistical procedures. The first pioneering applications in ecology and evolution demonstrate that meta-analysis is both tractable and powerful.

Evidence for the involvement of TNF and NF-κB in hippocampal synaptic plasticity

Abstract: The cytokine tumor necrosis factor-alpha (TNF), well-known for its roles in cellular responses to tissue injury, has recently been shown to be produced in response to physiological activity in neuronal circuits. TNF stimulates receptors in neurons linked to the activation of the transcription factor NF-kappaB, and recent findings suggest that this signaling pathway can modulate neuronal excitability and vulnerability of neurons to excitotoxicity. Because data indicate that TNF is produced, and NF-kappaB activated, under conditions associated with learning and memory, we performed experiments in the hippocampal slice preparation aimed at elucidating roles for TNF and NF-kappaB in modulating synaptic plasticity. Whereas stimulation of Schaffer collateral axons at a frequency of 1 Hz induced long-term depression (LTD) of synaptic transmission in region CA1 of wild-type mice, LTD did not occur in slices from TNF receptor knockout mice. Stimulation at 100 Hz induced long-term potentiation (LTP) in slices from both wild-type mice and mice lacking TNF receptors. Basal transmission was unaltered in mice lacking TNF receptors. Pretreatment of slices from wild-type mice with kappaB decoy DNA prevented induction of LTD and significantly reduced the magnitude of LTP. Collectively, these data suggest important roles for TNF and signaling pathways that modulate NF-kappaB activity in regulation of hippocampal synaptic plasticity.