179 research outputs found

    Freshwater Food Habits of Salvelinus malma (Walbaum) on Amchitka Island, Alaska

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    Stomach contents of 3,672 Dolly Varden char collected from September 1967 to November 1968 were examined to determine the food habits of this species. Of these, 3,100 (86%) had food in their stomachs. Aquatic invertebrates (Insecta and Crustacea) comprised over 90% of the diet. Food habits varied with habitat. Aquatic insects were most important in the diet of stream fish while aquatic insects and crustaceans were most important in the diet of lake fish. Food habits of lake fish were re- 1ated to lake bottom type and access to the sea. Fish in landlocked lakes fed primarily on aquatic insects, fish, and fish eggs. In lakes with access to the sea, crustaceans, followed by aquatic insects, were the major food items in those with firm bottoms adjacent to shore while aquatic insects, followed by crustaceans, were the major food items in those with muck bottoms adjacent to shore. As fish size increased, feeding activity decreased and aquatic insects became less important in the diet while crustaceans and fish became more important. During summer, feeding activity was highest for lake fish while it was highest during autumn and summer for stream fish. Aquatic insects were the dominant food item in summer while crustaceans and fish were dominant in spring and autumn. Mature and immature fish of similar size ate similar organisms. Mature fish, however, fed more sporadically prior to spawning. Feeding activity was highest during daylight hours. Dolly Varden selected larger food items, such as insects and amphipods and ignored small items such as nematodes and oligochaetes

    Damage to physicians' gloves during “routine” cardiac catheterization: An underappreciated occurrence

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    AbstractRecently, concern for the protection of health care employees and health care recipients has led to increasing awareness of transmitted infections. However, it is evident that damage of barrier methods of controlling infection can occur and go undetected. In a prospective study conducted from January 13, 1989 through February 15, 1989, 100 sequential pairs of gloves (200 gloves) worn during routine pediatric cardiac catheterizations were evaluated for punctures. A control group of 25 pairs of unused physicians' gloves was also evaluated for the presence of spontaneous leakage.In the 25 pairs of unused gloves (50 gloves), no punctures were detected, whereas in the 200 gloves worn during the catheterization procedures, punctures were found in 38 gloves or 19% (p < 0.001). When comparing the frequency of punctures with respect to the digits, 81% of the punctures were detected within the thumb and index finger of the gloves. In the majority of instances, physicians describe stopcock manipulation as the cause of the punctures. Implication of the stopcock as a possible mechanism for glove damage can be isolated to the stop mechanism on the stopcock pivot.Although surgeons' gloves are worn in many procedures besides surgery, no previous studies have defined the incidence of glove punctures during these procedures. Recommendations include a redesign of the stopcock as a protective measure and immediate change of latex surgeons' gloves whenever damage is suspected

    High-Fat Feeding Does Not Disrupt Daily Rhythms in Female Mice Because of Protection by Ovarian Hormones

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    Obesity in women is increased by the loss of circulating estrogen after menopause. Shift work, which disrupts circadian rhythms, also increases the risk for obesity. It is not known whether ovarian hormones interact with the circadian system to protect females from obesity. During high-fat feeding, male C57BL/6J mice develop profound obesity and disruption of daily rhythms. Since C57BL/6J female mice did not develop diet-induced obesity (during 8 weeks of high-fat feeding), we first determined if daily rhythms in female mice were resistant to disruption from high-fat diet. We fed female PERIOD2:LUCIFERASE mice 45% high-fat diet for 1 week and measured daily rhythms. Female mice retained robust rhythms of eating behavior and locomotor activity during high-fat feeding that were similar to chow-fed females. In addition, the phase of the liver molecular timekeeping (PER2:LUC) rhythm was not altered by high-fat feeding in females. To determine if ovarian hormones protected daily rhythms in female mice from high-fat feeding, we analyzed rhythms in ovariectomized mice. During high-fat feeding, the amplitudes of the eating behavior and locomotor activity rhythms were reduced in ovariectomized females. Liver PER2:LUC rhythms were also advanced by ~4 h by high-fat feeding, but not chow, in ovariectomized females. Together these data show circulating ovarian hormones protect the integrity of daily rhythms in female mice during high-fat feeding

    Friedman tongue position and cone beam computed tomography in patients with obstructive sleep apnea

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139112/1/lio292.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139112/2/lio292_am.pd

    Endosomal accumulation of APP in wobbler motor neurons reflects impaired vesicle trafficking: Implications for human motor neuron disease

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    Palmisano R, Golfi P, Heimann P, et al. Endosomal accumulation of APP in wobbler motor neurons reflects impaired vesicle trafficking: Implications for human motor neuron disease. BMC Neuroscience. 2011;12(1): 24.Background: The cause of sporadic amyotrophic lateral sclerosis (ALS) is largely unknown but hypotheses about disease mechanisms include oxidative stress, defective axonal transport, mitochondrial dysfunction and disrupted RNA processing. Whereas familial ALS is well represented by transgenic mutant SOD1 mouse models, the mouse mutant wobbler (WR) develops progressive motor neuron degeneration due to a point mutation in the Vps54 gene, and provides an animal model for sporadic ALS. VPS54 protein as a component of a protein complex is involved in vesicular Golgi trafficking; impaired vesicle trafficking might also be mechanistic in the pathogenesis of human ALS. Results: In motor neurons of homozygous symptomatic WR mice, a massive number of endosomal vesicles significantly enlarged (up to 3 mu m in diameter) were subjected to ultrastructural analysis and immunohistochemistry for the endosome-specific small GTPase protein Rab7 and for amyloid precursor protein (APP). Enlarged vesicles were neither detected in heterozygous WR nor in transgenic SOD1(G93A) mice; in WR motor neurons, numerous APP/Rab7-positive vesicles were observed which were mostly LC3-negative, suggesting they are not autophagosomes. Conclusions: We conclude that endosomal APP/Rab7 staining reflects impaired vesicle trafficking in WR mouse motor neurons. Based on these findings human ALS tissues were analysed for APP in enlarged vesicles and were detected in spinal cord motor neurons in six out of fourteen sporadic ALS cases. These enlarged vesicles were not detected in any of the familial ALS cases. Thus our study provides the first evidence for wobbler-like aetiologies in human ALS and suggests that the genes encoding proteins involved in vesicle trafficking should be screened for pathogenic mutations

    Acute effects of vasoactive drug treatment on brachial artery reactivity

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    AbstractObjectivesThe goal of this study was to investigate whether concomitant therapy with vasoactive medications alters the results of noninvasive assessment of endothelial function.BackgroundUltrasound assessment of brachial artery flow-mediated dilation is emerging as a useful clinical tool. The current practice of withholding cardiac medications before ultrasound studies has unknown utility and would limit the clinical use of the methodology.MethodsTo determine whether a single dose of a vasoactive drug influences brachial reactivity, we examined flow-mediated dilation and nitroglycerin-mediated dilation in 73 healthy subjects (age 27 ± 6 years). Studies were completed at baseline and 3 h after randomized treatment with a single oral dose of placebo, felodipine (5 mg), metoprolol (50 mg), or enalapril (10 mg). To determine if holding vasoactive therapy for 24 h before study yields different results than continuation of clinically prescribed medications, we examined vascular function in 72 patients (age 57 ± 10 years) with coronary artery disease. Ultrasound studies were performed 24 h after the last dose and again 3 h after patients took their clinically prescribed medications.ResultsIn healthy subjects one dose of all three drugs lowered blood pressure, and metoprolol also lowered heart rate. However, there was no significant effect of treatment on brachial artery dilation. In patients with coronary artery disease on chronic treatment, taking prescribed medications reduced blood pressure and heart rate, but had no significant effect on brachial artery dilation.ConclusionsRecent administration of commonly used nonnitrate vasoactive drugs has no significant effect on brachial reactivity. These findings suggest that current practice of withholding cardiac medications before testing endothelial function may not be necessary, making this methodology more practical for clinical use

    An Investigation into the Stability of Graphitic C3N4 as a Photocatalyst for CO2 Reduction

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    The increasing CO 2 concentration in the atmosphere exerts a significant influence on global warming and climate change. The capture and utilization of CO 2 by conversion to useful products is an area of active research. In this work, the photodriven reduction of CO 2 was investigated using graphitic carbon nitride (g-C 3 N 4 ) as a potential photocatalyst. The photocatalytic reduction of CO 2 was investigated with g-C 3 N 4 powder immobilized on a glass support in a batch gas-phase photoreactor. The experiments were carried out under UV-vis irradiation at 70 \ub0C and an initial pressure of 2.5 bar. The only gas-phase product detected during the irradiation of the g-C 3 N 4 in the presence of CO 2 was CO, and the rate of production was observed to decrease over time. Oxygen-doped g-C 3 N 4 was also tested for CO 2 reduction but had efficiency lower than that of the parent g-C 3 N 4 . Repeated cycles of photocatalytic CO 2 reduction showed a decline in the activity of the g-C 3 N 4 . In the absence of CO 2 some CO generation was also observed. Characterization of used and unused materials, using FTIR and XPS, showed an increase in the oxygen functional groups following UV-vis irradiation or thermal treatment. While others report the use of g-C 3 N 4 as a photocatalyst, this work highlights the important need for replicates and control testing to determine material stability

    Topologically non-trivial metal-organic assemblies inhibit beta(2)-microglobulin amyloidogenesis

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    Inhibiting amyloid aggregation through high-turnover dynamic interactions could be an efficient strategy that is already used by small heat-shock proteins in different biological contexts. We report the interactions of three topologically non-trivial, zinc-templated metal-organic assemblies, a [2]catenane, a trefoil knot (TK), and Borromean rings, with two β2-microglobulin (β2m) variants responsible for amyloidotic pathologies. Fast exchange and similar patterns of preferred contact surface are observed by NMR, consistent with molecular dynamics simulations. In vitro fibrillation is inhibited by each complex, whereas the zinc-free TK induces protein aggregation and does not inhibit fibrillogenesis. The metal coordination imposes structural rigidity that determines the contact area on the β2m surface depending on the complex dimensions, ensuring in vitro prevention of fibrillogenesis. Administration of TK, the best protein-contacting species, to a disease-model organism, namely a Caenorhabditis elegans mutant expressing the D76N β2m variant, confirms the bioactivity potential of the knot topology and suggests new developments

    Computational Modeling for the Activation Cycle of G-proteins by G-protein-coupled Receptors

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    In this paper, we survey five different computational modeling methods. For comparison, we use the activation cycle of G-proteins that regulate cellular signaling events downstream of G-protein-coupled receptors (GPCRs) as a driving example. Starting from an existing Ordinary Differential Equations (ODEs) model, we implement the G-protein cycle in the stochastic Pi-calculus using SPiM, as Petri-nets using Cell Illustrator, in the Kappa Language using Cellucidate, and in Bio-PEPA using the Bio-PEPA eclipse plug in. We also provide a high-level notation to abstract away from communication primitives that may be unfamiliar to the average biologist, and we show how to translate high-level programs into stochastic Pi-calculus processes and chemical reactions.Comment: In Proceedings MeCBIC 2010, arXiv:1011.005
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