Publications by authors named "Agnew W"

Background: American Indian and Alaskan Native individuals experience disproportionate levels of chronic health conditions such as type 2 diabetes and overweight and obesity that are influenced by dietary patterns and food choices. Understanding factors that influence healthy food choices among tribal college students can enrich education and programs that target dietary intake.

Objective: To build an understanding of factors that influence healthy food choices among tribal college students at increased risk for college attrition.

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Practical Relevance: Inappetence is a commonly encountered problem in feline medicine. Primary goals in managing the inappetent or anorectic cat are to diagnose and treat the underlying disease and reinstate adequate nutrition.

Rationale: As cats are intolerant of prolonged periods of inadequate nutritional intake, especially given their propensity to develop hepatic lipidosis, their increased requirements for amino acids, and inability to slow their rate of gluconeogenesis, symptomatic therapy and nutritional support is often required during diagnostic investigations.

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An 11-month-old neutered female weimaraner was humanely destroyed 6 days after an acute onset of neurological signs. At necropsy examination the pituitary gland was replaced by a large neoplastic mass that compressed and infiltrated the overlying hypothalamus. Small nodules were detected in the spleen, kidneys and stomach.

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Streptococcus iniae has become one the most serious aquatic pathogens in the last decade causing high losses in farmed marine and freshwater finfish in warmer regions. Although first identified in 1976 from a captive Amazon freshwater dolphin, from which it derives its name, disease outbreaks had most likely been occurring for several decades in marine aquaculture in Japan. S.

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Background: RNA metabolism, through 'combinatorial splicing', can generate enormous structural diversity in the proteome. Alternative domains may interact, however, with unpredictable phenotypic consequences, necessitating integrated RNA-level regulation of molecular composition. Splicing correlations within transcripts of single genes provide valuable clues to functional relationships among molecular domains as well as genomic targets for higher-order splicing regulation.

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We describe the regulated transcriptome of CACNA1G, a human gene for T-type Ca(v)3.1 calcium channels that is subject to extensive alternative RNA splicing. Fifteen sites of transcript variation include 2 alternative 5'-UTR promoter sites, 2 alternative 3'-UTR polyadenylation sites, and 11 sites of alternative splicing within the open reading frame.

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Highly alternatively spliced genes may provide complex targets for disease mutations. Structural changes created by missense mutations may differentially affect the activity of alternative gene products, whereas missense, silent and non-coding mutations may alter developmental regulation of splice variant expression. CACNA1H is a human gene encoding Ca(v)3.

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In order to use recorded neural activities from the brain as control signals for neuroprosthesis devices, it is important to maintain a stable interface between chronically implanted microelectrodes and neural tissue. Our previous paper introduced a method to quantify the stability of the recording microelectrodes. In this paper, the method is refined 1) by incorporating stereotypical behavioral patterns into the spike sorting program and 2) by using a classifier based on Bayes theorem for assigning the recorded action potentials to the underlying neural generators.

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The domain structure of proteins synthesized from a single gene can be remodeled during tissue development by activities at the RNA level of gene expression. The impact of higher order RNA processing on changing patterns of protein domain selection may be explored by systematically profiling single-gene transcriptomes. itpr1 is one of three mammalian genes encoding receptors for the second messenger inositol 1,4,5-trisphosphate (InsP3).

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Microelectrodes using activated iridium oxide (AIROF) charge-injection coatings have been pulsed in cat cortex at levels from near-threshold for neural excitation to the reported in vitro electrochemical charge-injection limits of AIROF. The microelectrodes were subjected to continuous biphasic current pulsing, using an 0.4V (versus Ag|AgCl) anodic bias with equal cathodal and anodal pulse widths, for periods up to 7h at a frequency of either 50Hz or 100Hz.

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Our objective is to develop neural prostheses based on an array of microelectrodes implanted into the sacral spinal cord, that will allow persons with spinal cord injuries to regain control of their bladder and bowels. For our chronic cat model, we have developed two microelectrode arrays, one type containing nine discrete activated iridium microelectrodes and the second utilizing silicon substrate probes with multiple electrode sites on each probe. Both types can elicit an increase in the pressure within the urinary bladder of more than 40-mm Hg and/or relaxation of the urethral sphincter.

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P/Q-type (Ca(v)2.1) calcium channels support a host of Ca2+-driven neuronal functions in the mammalian brain. Alternative splicing of the main alpha1A (alpha1(2.

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This study was conducted to examine the excitability changes induced in cerebral cortical neurons during prolonged microstimulation with a spatially dense microelectrodes array. The arrays of 16 iridium microelectrodes were implanted chronically into the postcruciate gyrus of cats. Neuronal responses characteristic of single pyramidal tract axons (ULRs) were recorded in the medullary pyramid.

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Alternative splicing of pre-mRNA may generate many distinct proteins from a single gene: regulation of alternative exon selection constitutes control of molecular structure downstream of transcription. Identifying natural splice variants among hundreds or thousands of theoretical alternatives, and examining the regulation of exon selection at multiple sites, may require screening many full-length cDNAs. We describe methods for preparing full-length cDNA libraries comprising the splice variants from single genes.

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The structure of CACNA1G, the gene encoding alpha1G, a human brain T Ca2+ channel alpha1 subunit, was determined by comparison of polymerase chain reaction-amplified brain cDNA and genomic sequences. The gene consists of at least 38 exons, two of them newly-identified, spanning at least 66490 basepairs of chromosome 17q22. Alternative splicing of the RNA occurs at six sites: cassette exons 14, 26, 34 and 35, an internal donor in exon 25 and protein-coding intron 38B.

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The stability of the interface between neural tissue and chronically implanted microelectrodes is very important for obtaining reliable control signals for neuroprosthetic devices. Stability is also crucial for chronic microstimulation of the cerebral cortex. However, changes of the electrode-tissue interface can be caused by a variety of mechanisms.

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We describe the evolution of axonal injury following the induction of neural damage by electrical stimulation. The sciatic nerves of cats were stimulated continuously for 8 h with charge-balanced waveforms at high intensities, 50 Hz and 2100-4500 microA, using circumneural helical electrodes. Computer-assisted morphometric and ultrastructural studies indicate that many of the damaged fibers had not regenerated by 125 days after stimulation.

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The structure of CACNA1I, the gene encoding alpha1I, a human brain T Ca2+ channel alpha1 subunit, was determined by comparison of polymerase chain reaction-amplified brain cDNA and genomic sequences. The gene consists of at least 36 exons spanning at least 115,168 basepairs of chromosome 22q12.3-13.

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Localized, long-lasting stimulation-induced depression of neuronal excitability (SIDNE) is a consequence of prolonged, high-frequency microstimulation in the central nervous system (CNS). It represents a persisting refractory state in the neurons and axons near the stimulating microelectrode, that occurs in the absence of histologically detectable tissue injury. It does not involve a change in synaptic efficacy and, in this respect, it differs from the more familiar phenomenon of long-term depression (LTD).

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We describe a computer-assisted morphometric procedure for quantifying acute axonal injury induced in peripheral nerves by prolonged electrical stimulation. The procedure is a two-phase process, with the image analysis implemented via a commercial image analysis program, followed by an automated editing of the morphometric parameters of each object identified by the image analysis software. Both phases are implemented on IBM-compatible personal computers.

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Voltage-gated rat skeletal muscle and cardiac Na+ channels are modulated by exogenous unsaturated fatty acids. Application of 1-10 microM arachidonic or oleic acids reversibly depressed Na+ channel conductance and shifted the inactivation curve to hyperpolarizing potentials. These effects were not prevented by inhibitors of lipoxygenase, cyclooxygenase, cytochrome P-450 epoxygenase, or protein kinase C.

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The opisthotonos (opt) mutation arose spontaneously in a C57BL/Ks-db2J colony and is the only known, naturally occurring allele of opt. This mutant mouse was first identified based on its ataxic and convulsive phenotype. Genetic and molecular data presented here demonstrate that the type 1 inositol 1,4,5-trisphosphate receptor (IP3R1) protein, which serves as an IP3-gated channel to release calcium from intracellular stores, is altered in the opt mutant.

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Voltage-gated K+ channels are modulated by extracellular free unsaturated fatty acids. Both increases and attenuations of K+ channels activities have been observed. We studied the effect of cis-unsaturated fatty acids on Shaker B delta6-46 and the endogenous outward rectifier K+ channels expressed in COS cell line, using the whole cell recording technique.

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Active microelectrodes were implanted for a period of 2 weeks to 3 months into the sacral spinal cord of 10 male cats in order to test the feasibility and the safety of discrete stimulation of the parasympathetic preganglionic nucleus for future clinical applications of microelectrode technology in micturition control. An array of four 50 microns-diameter iridium microelectrodes was inserted beneath the dura in each cat. At weekly intervals, bladder pressure was measured as hydrostatic pressure on an intraluminal catheter.

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The adult skeletal muscle Na+ channel mu1 possesses a highly conserved segment between subunit domains III and IV containing a consensus protein kinase C (PKC) phosphorylation site that, in the neuronal isoform, acts as a master control for "convergent" regulation by PKC and cAMP-dependent protein kinase. It lacks an approximately 200-aa segment between domains I and II though to modulate channel gating. We here demonstrate that mu1 is regulated by PKC (but not cAMP-dependent protein kinase) in a manner distinct from that observed for the neuronal isoforms, suggesting that under the same conditions muscle excitation could be uncoupled from motor neuron input.

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